DEVELOPMENT AND STANDARDIZATION OFSTAGGERED SPONDAIC WORD (SSW) LIST IN

BANGLA

SAYANI BARI1, MR INDRANIL CHATTERJEE2*

1 Audiologist and Speech Language Pathologist, ICMR Project, Dept. Of ENT, North Eastern Indira Gandhi Regional Institute of Health and Medical Science, Mawdiangdiang, Shillong,

Meghalaya-793018

2 Lecturer, Ali Yavar Jung National Institute for the Hearing Handicapped, Eastern Regional Center, B.T. Road, NIOH Campus, Bonhooghly, Kolkata-700090.

*Corresponding Author

Abstract:

Staggered Spondaic (bisyllabic equal stress) Word (SSW) is a dichotic test. The Dichotic listening tests is a behavioural test battery to assess the hemispheric function, inter-hemispheric transfer of information, and development and maturation of auditory nervous system. Staggered Spondaic Word (SSW) is more sensitive for brainstem and cortical lesion. The current investigation was aimed to develop and standardize staggered spondaic word (SSW) list in Bangla for assessing the central auditory processing of native Bengali listener. In this regard 200 sets of Bangla bisyllabic words were collected where each set contained a pair of spondee words: first syllable of first spondee word and last syllable of second spondee word made another spondee word. Based upon this concept sets of the staggered spondee words were fixed. Then familiar staggered spondaic word sets had been selected and stress pattern was judged. From where finally 40 sets bisyllabic equal stress words were selected. The final SSW list was recorded in a sound recording studio by an adult female standard native Bengali speaker. Each word was fitted into a separate track and then track had been overlapped and stimulus had been modified. The developed test stimulus was standardized on 30 male and 30 female normal native Bengali listeners (18-40 years). Error scores and pattern of error had been analyzed. These were not significantly present on normal (P> 0.05).There was no significant gender effect and laterality effect on SSW test (P>0.05) on SSW test performance scores. Test- Retest reliability was obtained. The Pearson moment correlation coefficient showed there was a strongly positive correlation between test and retest trial. The standardized test was validated on six age matched native Bengali language learning disability (LLD) patients. There was a significant difference between performance on normal listeners and LLD listeners (P<0.05).

Key Words: Staggered, Spondee, Dichotic, Hemisphere, Brainstem, Cortex, Language learning disability.

INTRODUCTION

Auditory processing stated simply is “what we do with what we hear”33. It is the abstraction of meaning from an acoustic signal and the retrieval of that meaning12. According to American Speech-Language and Hearing Association (ASHA) census in the year 19962, an auditory processing disorder (APD) was defined as an observed deficiency in one or more of

the following behaviours: i) Sound localization and lateralisation ii) Auditory Discrimination iii) Auditory pattern recognition iv) Temporal aspects of Auditions, including temporal resolution, masking, integration and temporal ordering v) Auditory performance with competing acoustic signals vi) Auditory performance with degraded acoustic signals. An APD was defined more broadly a deficits in information processing specific to the auditory modality. It may be associated with difficulties in listening, speech understanding, language development and learning58. Therefore it is conceptualized purely as a deficit in processing of auditory input29. APD’s are primarily based on deficits in hierarchical processing of acoustic signal in the afferent nervous system and the evoked nerve pulses, and neural activities53. Adults with an APD complain difficulties in speech understanding especially in adverse listening conditions for instance in a room with background noise61. Other symptoms are explained like difficulties in following oral instruction, difficulties with rapid/ degraded speech and with auditory closure, inattention and distractibility5.

Auditory Processing Disorder or APD has been erroneously confused with other disorders such as dyslexia, learning disabilities, and attention deficit disorders. Fortunately, recent developments show a growing awareness of the disorder on the part of professionals, parents, educators, and the general public. Numerous sites have emerged on the internet with reference to CAPD. Clinical programs, addressing auditory processing and its disorders are being developed, focusing on interdisciplinary collaboration between speech-language pathologists, neuroscientists, neuropsychologists, and professionals and scientists in countless other disciplines. They are united in their quest to define, understand, diagnose, and treat auditory processing disorders6.

Investigators have attempted to document the heterogeneous nature of APDs by sub-grouping APD or describing the characteristics in terms of commonalities7, 33, 48. Although this may be beneficial in management, no sub-grouping system or model is universally accepted.

The Buffalo Model37 focuses on the relationship between patterns of performance on one particular test of auditory processing, and learning difficulties in children. This model contains four subtypes: (i) decoding (ii) Tolerance- Fading Memory (iii) Integration and (iv) Organization. Decoding describes individuals who “have difficulty keeping up with the flow of communication, have poor phonemic skills, are slow responders, often have articulation errors, have difficulty following directions, and have weak oral reading and spelling skills”61. Persons with tolerance-fading memory have difficulty understanding speech with competing background noise and have short-term memory problems1.

These individuals are often described as impatient and are easily over-stimulated.

They tend to have poor reading comprehension and may have handwriting difficulty. Persons with integration problems have difficulty integrating the auditory modality with other nonverbal aspects of speech such as word finding, morphological and syntactical errors, or an expressive language disorder17. Organization describes persons who have difficulty sequencing events and have sequencing errors 55. These individuals are often disorganized at home or school. Often a person will exhibit characteristics of more than one sub-type.

Auditory Processing Test

Many tests have been proposed in order to diagnose central auditory processing disorder. American Speech and Hearing Association (ASHA) CAPD taskforce in 19962

stated that assessment of APD should consist of: i) gathering information about the patient’s

history; ii) non-standardized but systematic observation of auditory behaviour; iii) several audiological test procedures (behavioural tests, possibly supplemented with electrophysiological tests); iv) Speech-Language pathology measurements. Behaviourally auditory processing disorders are based on the principle of reducing the redundancy of speech material. Accordingly, a division can be made into two categories: those that add information to the signal and those that remove information from the signal8. A test battery must stress the central auditory nervous system at various levels to identify areas of weakness. Although use of a test-battery is recommended for the diagnosis of APD33, 49 there is no statistically compelling evidence indicating which tests should be included in the battery, which tests correlate with other tests, or the cost-effectiveness of each test60. However, the authors had used Staggered Spondaic Word Test amongst the various central auditory test battery test materials to assess the same.

Staggered Spondaic Word Test

Staggered Spondaic Word (SSW) is a dichotic test30, 31. SSW test offers the diagnostician many sources of information regarding individual’s ability to respond to and cope with complex speech stimuli29. Before development of SSW the earliest speech tests for diagnosing central auditory disorder were a gradual trend to include stable materials31. ‘Stable materials’ was meant familiar speech containing considerable redundancy 13, 25, 38, 33. These materials are less likely to be affected by peripheral hearing loss except distorted speech materials. In order to challenge nervous system, complex presentation of materials came into use and therefore, primary auditory system was investigated perhaps areas of secondary auditory functions perhaps areas of secondary functions. In SSW test speech stimuli are presented in both competing and noncompeting conditions. This procedure assesses more abstract functions rather earlier developed tests for CAPD33. This test has been shown to be sensitive to brainstem and cortical lesions1.

During presentation of SSW, for each test item a couple of spondaic words are presented with staggered onset, one to each ear. There are three separate sequential events: i) the first half of the first spondaic word (monosyllabic word) is presented in isolation to one ear ii) followed by the second half of the first spondaic word (monosyllabic word) to the same ear simultaneously with the first half of the second spondaic word (monosyllabic word) in the other ear iii) followed by the second half of the second spondaic word (monosyllabic word) in that ear. The first event with the monosyllable in the first ear is a noncompeting event (NC); the second event with different monosyllables in each ear is the competing event i.e., right competing (RC) and left competing (LC); the third event with monosyllable in the second ear is also a noncompeting event (NC). The spondaic words are familiar words. When the noncompeting segments of each item are combined, they also form familiar, spondaic words58. There are 40 sets of spondee words that mean total 80 spondees. Spondees are presented at 50dBSL threshold with reference to three frequency average as pure tone average. The participant is asked to repeat both the spondees. The following figure (Figure: 1.) shows right Noncompeting (RNC) - Up; right competing (RC) - stairs; left competing (LC) -down; left non competing (LNC) - town.

Figure-1: The Block diagram of Staggered Spondaic Word presentation

Substitutions, omission, and additions and incorrect repetition are considered as error response. At the end of the test the total numbers of error response are noted down for each condition. The total no. of errors in every condition is listed down. From each error score Raw SSW (R-SSW) % scores are obtained. Corrected SSW (C-SSW) % scores are obtained by subtracting discrimination loss at peripheral level. Discrimination Loss is the difference between when 100% and the % of word of a phonetically balanced (PB) list that a listener repeat correctly when a list is presented at an intensity level that is so high that further increase in intensity will not increase the articulation28. Adjusted SSW score (A-SSW) % is obtained from the response biases are like ear effect, order effect, response reversal, pattern effect. Response bias refers to any one of a number of unlikely responses that persist in patients test performance. Usually it is presumed that a normal cooperative subject will make random errors when the items are presented right ear first or left ear first. If the subject makes consistent errors when the left ear was leading then this is a type of response bias called ear effect. Therefore, ear effect, is a type of response bias, represents a tendency to make more errors on items when the right- ear is first (REF) than when the left is first (LEF) or vice versa. If the score of ear effect is more than five than it will be said that ear effect is said to be present significantly. Order effect is a type of response bias where the participants have a tendency to make more errors on the 1st spondee than on 2nd spondee or vice versa per item. If the error score will be more than five, the order effect is said to be considered as significantly present. When the participant repeats 2nd spondee word instead of 1st spondee, the reversal response is said to be considered. Two different configurations of error will be exhibited if for the right ear first items as opposed to the left ear first item.

In Indian context SSW was developed and standardized in Kannada language known as staggered paired word test50. In Kannada language as there were lacks of bisyllabic spondee word hence paired words were used.

NEED OF THE STUDY

Any lesion at the level of central auditory system disrupts auditory processing skills5. As consequences, the whole communication process gets affected. Therefore, the areas related to communication like academic background, social interaction and vocations are also got affected1. The result can affect the individual potentiality. Hence, such conditions have to be identified as early as possible and appropriate remediation strategies must be provided. Sometimes, various subtle changes in neural structure may not be detectable even by the sophisticated radiological/ neurological techniques. Such conditions may include various

degenerative disease (particularly in the initial stages), biochemical alterations of the brain and a host of minimum neurological deficits 18.

There are very few tests available in Indian Languages regarding CAPD. Language is an important issue for developing and standardization of a test battery. It has an important influence on the outcomes in the tests which are linguistically loaded. Very few tests have been standardized in Indian population. Population specific criteria are crucial for interpretation of the results obtained from such tests because the normative differs in different populations. There is a need for developing assessment and remediation tools which are not appropriately and unduly influenced by western thought, practice and materials.

Near about 230 million total speakers speak Bangla24. Bangla is the very primary spoken language in Bangladesh and second most spoken language in India69. Inspite of having such a wide use of Bangla language no such work have been reported in the area of Auditory Processing skills among native Bangla speakers.

SSW has been preferred because the dichotic technique in SSW test appears to be highly sensitive to the presence of lesions in many parts of the central nervous systems. The test is particularly powerful when all of its qualitative and quantitative indicators are used. The raw score and the corrected score of SSW are the quantitative indicators, where as the response biases give the most sensitive localizing information of qualitative indicators. Corrected SSW score helps in neutralizing peripheral hearing distortion. The particular response bias pattern has also diagnostic significance in indicating various sites of brain dysfunction. This test has been used in conjunction with competing environment sound for the purpose of improving the prediction of involved hemisphere. On average the time required to administer the test is approximately 10 minutes as compared to other tests.

SSW test has been standardized and developed first in English language30, 31 in order to diagnose central auditory processing disorder. Then SSW has been developed and standardized in Spanish language54 and French version56 and Australian SSW 72. In Indian context SSW test is available in Kannada known as Staggered paired word test50. In fact, there is no specific data for SSW in Bangla language.

Hence, an attempt has been made in order to develop and standardize staggered spondaic word list in Bangla which would serve as a test for assessing auditory processing skills. Thus, the present study attempts to investigate the auditory perception abilities for Staggered Spondaic Word among adult native Bangla speakers.

METHODOLOGY

Participants

The participants were categorized among two groups: I. 60 participant including 30 males (Mean age-26.3; Standard Deviation- 4.96) and 30

females (Mean age-22.63; Standard Deviation-3.19) with age range 18-40 years.II. Six diagnosed Language Learning Disability (LLD) patients with age range 18-40

years (Mean age- 23.67; SD-1.21 ;)

Inclusion Criteria for the Group-I:

The selected participants were native Bengali speaker. All the participants were right handed. Right-handedness was confirmed by administering the Edinburgh Handedness Inventory51, which is a simple 10-item questionnaire that provides a quantitative assessment of handedness. Individuals selected for the present study scored ≤ 20 on the questionnaire to ensure the subjects right-handedness. The participants had hearing sensitivity within normal limits i.e., 25dBHL at pure tone thresholds at octave frequencies 250-8000 Hz. All the individuals should have word discrimination score (WDS) more than 90%. All participants had normal otoscopy findings comprised of a clear external ear canal, a healthy tympanic membrane, and no sign of structural anomalies. Ear, Nose and Throat (ENT) specialist opined the same as well. Tympanometry results were within normal limits, and all individuals were health during testing with no complain of illness which might affect the performance of hearing speech. Minimum qualification should be higher secondary education and these participants should have Bangla as first and English as second language. Misarticulation, Dysarthria or any neurological impairment, Cognitive impairment, Language Learning Disability were excluded from Group-I Participants.

Inclusion Criteria for the Group-II:

The selected participants from this group were also native Bengali speaker, right handed, normal hearing, normal otoscopic findings, normal tympanometric findings and minimum qualification was higher secondary education with Bangla as fist language and English as second language. Individual having Dysarthria or other neurological or cognitive impairment were excluded from the study. But there was an exceptional finding for participant-1 of Group-II.

Participant –I was having hearing sensitivity within normal limits as per pure tone audiometry but as per speech audiometry very poor WDS, which was a symptom of Auditory Neuropathy Spectrum Disorder (ANSD). So for further confirmation he was referred for Otoacoustic emission (OAE) and auditory brainstem response (ABR) assessment. The Transient- Evoked OAE and The Distortion Product OAE showed bilaterally PASS indicative of outer hair cells were functioning normally and hearing sensitivities were expected to be within 30dBHL (tested in ERO.SCAN TM OAE). But as per ABR peak-V was not obtained up to 95dBnHL bilaterally having click rate 11.1 and 39.3, indicative of hearing problem at Central level rather Peripheral level (tested in Nicolet® and TECA® Supplies and Accessories ABR). So, these findings were strongly support the diagnosis of ANSD.

Instrumentations

An otoscope (Heine Beta ® 200) was used for ear external ear examination. The participants were tested in a double room Audiological testing suite at the Department of Audiology, in AYJNIHH, ERC using the MAICO MA 53 Dual Channel Diagnostic Audiometer. The stimulus (both pure tones and speech) were delivered monoaurally through the Telephonic TDH-39 supra-aural headphones. Prior to data collection, the equipment was calibrated using ANSI S3.6-2004 specifications. The earphones were calibrated using a Bruel & Kjaer (type 2235) sound level meter. Calibrated Immittance (GSI 38) meter was used to assess the status of middle ear. A Samsung laptop (Model no. RV411) with Pratt- 5.2.01 and adobe audition version 3.0 software were used for sound recording and sound monitoring

respectively. Nuendo (version 4.0) software was used for sound editing at sound recording studio. The recorded sound was burned into a CD by Nero Express. Recorded material was played by a Sony CD player (Model No. D-88). The responses of the individuals were recorded by a Sony digital tape recorder (Model No. -ICD-PX720).

Test Environment

A two room setup audiometric room was used. The environmental state of the test room was met with the current American National Standard Institute for background noise (ANSI S3.1-1999, R2003).

Procedure

Development of Test Material:

200 sets of Bangla bisyllabic words were collected from the corpus of news papers, story books, magazines, periodicals, and text books of West Bengal Board of Secondary Education and West Bengal Council of Higher Secondary Education. Each set of word contained a pair of bisyllabic words and its staggered bisyllabic words. No rhyming and reduplication words were included.

The each sets of words were distributed among ten adult professional native Bengali speakers to judge the familiarity by five point familiarity rating scale which was consisted of 1- unfamiliar, 2- doubtful, 3-not very familiar, 4- familiar, and 5- most familiar. For each set, its two bisyllabic words were rated along with its staggered word. For each set, each bisyllabic words and its staggered bisyllabic word was rated minimum 3 or more than 3, was considered as a familiar bisyllabic word set. In this way familiar word sets were extracted from the word set which were rated by at least nine individuals out of 10 individuals. In this way total 144 familiar word sets had been selected based upon frequency distribution.

Homogeneous stress pattern was formulated based on two intercorrelated measures: a) the each set of familiar Bangla bisyllabic word along with its staggered bisyllabic words were distributed among two linguists. In standard Bangla language stress is predominantly at initial syllable. Bangla words are virtually all trochaic; the primary stress falls on initial syllable of the word, while secondary stress falls on thereafter the odd-numbered syllable. However, in words borrowed from Sanskrit, the root syllable has a stress, out of harmony with the situation with native Bangla words16. In any case, Word-stress does not alter the meaning of a word, and is always subsidiary to sentence-stress16. Thus, apart from linguistic view in Bangla language, true spondee words are not available. Therefore, compound words in Bangla were taken into considerations because, the process of compounding make several words into a single system of accentuation. Thus, the uniformity in accentuation becomes responsible for bringing ease in pronunciation of compounds, which is hardly available in sentences21. Therefore, out of 144 familiar sets 60 sets of familiar Bangla compound words were selected by the linguists. b) The talker had presented the bisyllabic words with equal stress on both the syllable. Pratt (Version-5.2.01) software was for recording and visual analysis of stress pattern by means of frequency, intensity and duration analysis. After visual analysis finally total two staggered spondaic word (SSW) lists were made. Each list contained 20 sets of SSWs. Two word lists were added in order to make it randomly 40 sets of SSWs and four practice items were also added30, 31. Figures 2, 3 and 4 are exemplifying visual

analysis of symmetries in each syllable of three spondees. Thus, the two measures, one by the linguists and other by the Pratt Software (version 5.2.01) were strongly correlated at P=0.05.

Figure- 2: Pratt window for the word /d̪inkhɔn/ in English it means ‘Particular time of a day’

Figure- 3: Pratt window for the word /kɑlrɑt̪/ in English it means ‘One of the post-weeding Rituals in Bengali Community’

Figure-4: Pratt window for the word / d̪inrɑt̪/ in English it means ‘day-night’

Recording Parameter

The final SSW list was recorded in a sound recording studio. An adult female standard native Bengali speaker was considered as the speaker. The stimulus was recorded into the computer containing Praat (version-5.2.01) and Adobe Audition (version 3.0) software. The speaker was asked to speak at her best quality and instructed to maintain equal stress in each syllable with equal loudness during recording of the whole wordlists. The microphone was placed at a distance of six inches away from the mouth. The signal was digitized at sampling rate 44100Hz using 16 bit analogue to digital (A-D) and digital to analogue (D-A) converter housed within a computer. Each word was recorded in a separate file and then edited by Nuendo software version-4. Each word for a particular set was fitted into a separate track and then overlapped at last syllable of the first word and the first syllable of the second word. From this overlapped manner, sound output was simultaneously presented in both ears at second time sequence. Whereas, at first and third time sequence, the first syllable of first word and last syllable of second word in each set was presented into right ear first and left ear first in alternating manner. Figure-5 describes the overlapped spectral envelop of two spondaic words. The overlapping of competing two words was done perceptually30, 31. The recorded words were carried to edit the noise and the hiss reduction filter by Nuendo software. For some stimuli amplitudes were balanced by Adobe Audition version 3.0 and Nuendo software. Inter stimulus duration was five seconds along with carrier phrase before each stimulus27. After editing the complete prepared stimuli, it was burned into a digital versatile disc (DVD) at a bit rate of 16.

Figure-5: The overlapped spectral envelop of two spondees in two separate track.

Standardization of the newly developed test:

As per test protocol 500Hz, 1 KHz, 2 KHz, frequencies average pure tone threshold and word discrimination errors were recorded and percentage of scores for correct responses were obtained.

Staggered Spondaic Word Test: A list consisting 40 pairs of item was presented by a Sony CD player (Model no. - D-88). The CD player was connected with the dual channel MAICO MA 53 audiometer. The stimuli were presented at 50dBSL with reference to pure tone average15. Each individual heard the whole list along with four practice items. Therefore, individual heard for practice items 16 monosyllable and 160 monosyllables for test items.

Each item was introduced by the carrier phrase, /ɑpn̪i proʃt̪ut̪ ɑtʃʰen̪ t̪o? /. In English it means “Are you ready?” Items were arranged in this way so that the ear getting the first word was alternated.

A diagram of the time sequence was shown in Figure-6. It can be seen that each ear receives stimulation in isolation as well as in competition with other. For example there are total two paired words /d̪ɔʃd̪ik/ means ‘ten-sides’, / hin̪d͡ʒɔn̪/ means ‘guilt-feeler’. /d̪ɔʃ/ means ‘ten’ in English, is heard as a right non competing (R-NC) condition while /d̪ik/ means ‘side’ is hard in right competing (RC) and simultaneously /hin/̪ means ‘absent’ is hard in left competing (LC) conditions. Finally, /d͡ʒɔn̪/ means ‘individual’ is hard as left non competing (LNC) condition. The words were paired in such a way that the non competing words formed yet a third meaningful familiar spondee word as /d̪ɔʃd͡ʒɔn̪/ means ‘ten-individuals’. As illustrated, the ear stimulated first changes from item to item. Therefore, the second item was presented at left ear first. The two paired of spondaic words were /d̪ɔrbeʃ/ means ‘name of a sweet in Bengal’ and /ʃɔrkɑr/ means ‘government’. The word in LNC condition /d̪ɔr/ means ‘corridor’ , in LC condition / beʃ / means ‘dress’, in RC condition /ʃɔr/ means ‘layer of milk’ and in RNC condition /kɑr/ means ‘whom’ were presented. The third spondee was /d̪ɔrkɑr/ means ‘needed’. Attempt was done during construction of the items. Subjects were required to repeat both the spondee words, and a time gap of five seconds was allowed between each item for the participant to respond.

Figure-6: The time sequences of SSW items.

The test was administered as 50dB above the pure tone average. Four practice items were used before the test stimuli. If the subject failed consistently three times on practice session he was not taken up for the study.

Scoring: SSW scoring was done based on calculating no. of errors which was included incorrect repetition, substitution, omission, addition. Each half of the spondaic error would carry one mark. The participant had to respond by repeating the test items in the same order as they hard them. The response was monitored and recorded on a score sheet. An example of a score sheet is abbreviated on Table-1 by giving the practice items.

A: Right Noncompeting (RNC), B: Right Competing (RC), C: Left Competing (LC), D: Left Non Competing (LNC), E: Left Non Competing (LNC), F: Left Competing (LC), G: Right Competing (RC), H: Right Noncompeting (RNC). A, B, C, D, E, F, G, and H, these are called cardinal numbers; ‘Rev’ stands for reversal response. So, there are total eight cardinal numbers. Here, /phɑ̃kt̪ɑɬ/ means ‘absent of rhythm’ and /rɔʃhin/ means ‘dry’. Again /d̪eɓrɑd͡ʒ/ means ‘king of Angel and /monʃok/ means ‘mentally sad’.

Table-1: Example of SSW list illustrating the practice items

A B C D Reversal

Wrong

E F G H Reversal

Wrong

1 d̪ɔʃ d̪ik

hin

d͡ʒ ɔn

2 d̪ɔr beʃ ʃɔr kɑr

3 phɑ̃k

t̪ɑɬ rɔʃ hin

4 d̪eɓ

rɑd͡ʒ

roɠ

 ʃok

There are total 40 test items with four monosyllabic words in each item. Each word has been considered. If an item was said (regardless of order) it was correct. Nothing was done for this item. If a word was not responded by any reason, a horizontal line was drawn through it. To indicate error on the printed word of the score sheet, the person’s utterances was noted for substitution, addition and distortion. If the items were said in incorrect sequence, 1-4 numbers were used below the printed words. For example most common error in sequence was 3, 4, 1, and 2. No number was used for omission word. For entire correct items a dot (.) was entered into the wrong column. If there were errors in the item number of error was put into the wrong column.

Items were totalled in five ways:

i) Total monosyllable missed: The total percentage of correct responses indicate an individual’s overall success on this test. There were 160 possible errors for each condition.

ii) Right ear non-competing errors (R-NC): These monosyllables were hard in the right ear when there were no stimulus in the left ear. There were 40 possible errors.

iii) Left ear non-competing errors (L-NC): These monosyllables were hard in the left ear when there were no stimuli into the right ear. There were 40 possible errors.

iv) Right ear competing errors (R-C): These monosyllabic words were hard in the right ear where simultaneously a monosyllable was hard in left ear. There 40 possible errors.

v) Left ear competing errors (L-C): These words were hard in the left ear while simultaneously a monosyllable was hard in right ear. There were 40 possible errors on this.

In this way Raw-SSW (R-SSW) scores were calculated in each condition. Table-2 is representation of R-SSW % calculation.

Table-2: The R-SSW score calculation

R-SSWConditions RNC RC LC LNCTotal Errors

(TE)TE TE TE TE

Multiplier × 2.5 × 2.5 × 2.5 × 2.5R-SSW %

ScoreEar RE LE

R-SSW % errorTotal

From R-SSW% Error Corrected SSW (C-SSW) was calculated by subtracting discrimination loss. Discrimination loss was calculated from Word Discrimination Score (WDS). By subtracting obtained discrimination scores from the total discrimination scores. Table-3 is showing C-SSW % error calculation. For Group-I participants R-SSW scores and C-SSW scores were obtained.

Table-3: The C-SSW Score calculation

C-SSWEnter the R-SSW % error

Conditions RNC RC LC LNCR-SSW % error-discrimination

loss- - - -

C- SSW % ErrorEar RE LE

C-SSW % ErrorTotal

Test-Retest reliability has been measured after one week of first time testing by randomly selecting five males and five females participants from the Group-I.

The concomitant validity is an extent to which a cause and an effect occur together in the way predicted by the hypothesis under consideration43. SSW lists in Bangla was validated

in six diagnosed native Bengali language learning disability (LLD) (Group-II) having age range 18-40yrs (Mean-24; Standard deviation- 1.2). Pure tone average, immittance test, Speech Recognition Threshold and Word Discrimination Scores (WDS) were administered. Discrimination losses in each participant were also measured with reference to WDS. Standardized SSW list was administrated at 50dBSL (ref: three frequency pure tone average). Responses were recorded in the digital tape recorder. R-SSW score, Corrected SSW (C-SSW) score, Adjusted SSW (A-SSW) score were measured along with response biases.

Response Bias (RB) was originally thought to be idiosyncratic responses, but later it was found in people with brain lesions, that RBs were consistent with their site-of-lesion (Katz, 1984). The similar patterns were seen in those with CAPD having no history of brain damage. RBs were calculated in order to get Adjusted SSW (A-SSW) score. Therefore, A-SSW score was calculated in clinical population. There are four types of response biases:

Ear Effect: An ear effect, a type of response bias, represents a tendency to make more errors on items when the right-ear is first (REF) than when the left ear is first (LEF) or vice versa. When the score of ear effect was more than the cut off value it would be said that ear effect would present significantly. If REF is significantly greater it is referred to as Ear effect High/Low (REF has Higher). If LEF is significantly greater it is Ear effect Low/High (LEF is greater). Also in scoring with High/Low, REF minus LEF gives positive value, and with Low/High, REF minus LEF gives negative value. If sum of errors of even number columns minus sum of errors of odd numbers columns score would greater than the standardize value than ear effect would considered significantly present.

Order Effect: Order effect is a type of response bias where the participants have a tendency to make more errors on the 1st spondee than on 2nd spondee or vice versa. If the error score will be more than five, the order effect would be considered as significant. If 1st spondee has more errors than the 2nd it is Order Effect High/Low (first spondee more errors than second spondee) and vice versa. Order Effect High/Low when subtracted gives a positive value because the 1st spondee has more errors than the 2nd. Table-4 is showing calculation of order effect. If sum of errors of first spondee minus sum of errors of second spondee would be greater than the standardized value, order effect would be considered significant.

Table-4: The calculation of order effect

Order Effect1 2 3 4

(A+E) (B+F) (C+G) (D+H)Total

1st SpondeeTotal

2nd SpondeeSignificant Not Significant

Reversal Response: When the words of the item are repeated out of sequence and there is not more than one error it is a Reversal Response. The most common reversal is saying the second spondee first that is shown as 3, 4, 1, 2 below the printed words on score sheet.

Type-A Pattern: The eight Cardinal Numbers were considered on score sheet. For example errors for columns F vs. B were compared. The larger of the two columns were chosen and if it was ‘F’. Then from the remaining columns the one with the largest number of errors were chosen and if it was ‘X’. If F minus X is > the normal limit it is a Type-A pattern. The diagnostic significance of Ear/Order Effects were ignored if Type-A significant.

When highly positive C-SSW score were obtained and response biases were present, the Adjusted SSW score were obtained by lowering the C-SSW score by the magnitude of response bias. A-SSW score calculation has been shown on Table-5.

Table-5: The calculation of adjusted score

A-SSWEnter least Biased Score

Condition RNC RC LC LNCLeast biased errors (LBE)

LBE LBE LBE LBE

Multiplier ×5.0 ×5.0 ×5.0 ×5.0Least Biased

% error-WDS %

Error- - - -

A-SSW % ErrorEar RE LE

A-SSW % ErrorTotal

In the current investigation A-SSW score were not taken into consideration as this study did not intake participants having known site of lesion.

Statistical Analysis

The raw data was subjected to statistical analysis. Mean and standard deviation were calculated by using Statistical Package for Social Science (SPSS) Software (Version- 16.0). For hypotheses testing, R (Version- i386 3.0.1) software was used. One sample Wilcoxon sign rank test was performed for the judgement of pattern effects, reversal, ear and order effect because the outcomes of the distributions were not known. Two sample paired t test was performed to judge the gender effect and laterality effect where outcomes were assumed to be normally distributed. ‘Welch two sample t test’ was performed to estimate the difference of performance scores between normal and language learning disables where unequal sample sizes were present between the two variables under study.

RESULT

The results for the present study were explained under the following headings:

Development of the test material Standardization of test materials Test retest reliability Validity

Development of the test material

200 sets of Bangla bisyllabic words had been selected then these had been rated as familiar staggered spondaic words set based upon frequency distribution.

Figure-7:‘Box Plot’ for frequency distribution of next 1-200 sets based upon each sets minimum, maximum, 1st quartile and 3rd quartile value. ‘X’ Axis represents frequency distributions in average by means of Sets Minimum (S_MIN), Maximum (S_MAX), 1st Quartile (S_Q1) and Third Quartile ((S_Q3) Values with respect to Set No.’s in ‘Y’ Axis.

For the selected sets the frequency distribution lay within 7 to 15. These are the minimum and maximum value respectively and Box Plots upper whisker and Lower Whisker value. The Out liar values sets were also taken as familiar sets but below lower whisker values sets were not taken as a Familiar Sets.

Figure-8:‘Box plot’ of Selected Sets based upon frequency distributions. ‘X’ Axis represents frequency distributions in average by means of Sets Minimum (S_MIN), Maximum (S_MAX), 1st Quartile (S_Q1) and Third Quartile (S_Q3) Values with respect to Set No.’s in ‘Y’ Axis

Then from these selected sets stress pattern had been judged both qualitatively by experienced linguists and quantitatively by Pratt software in terms of frequency, intensity and time. Finally, 40 sets of staggered spondaic words had been selected.

Standardization of test materials

The first objective of the study was to study the performance of normal native Bengali Listeners on SSW and to establish the mean of the corrected SSW scores for the same. Table- 6 would representative of the normative of the C-SSW error scores of males and females.

Table: 6 Descriptive Statistics of average C-SSW error scores for 30 Normal Native Bengali Female and 30 Normal Native Bengali Male listeners

Gender N Minimum Maximum Mean Standard

Deviations

Female 30 1 29 12.83 8.76

Male 30 1 31 16.03 7.49

The table-6 represented mean C-SSW error scores of female was 12.83, and the standard deviation was 8.76 and mean C-SSW error scores of male was 16.03, and standard deviation was 7.49.

Next major concerns were to investigate pattern effects, ear effects, order effects and response reversals on normal listeners and to obtain the normative beyond that cut off value where pattern effect, ear effects, order effects and response reversal were significantly

present. In this concern of pattern effect, ear effect, order effect and reversal the responses were not normally distributed. As response’s distributions patterns were not known, exponential distribution was followed for each pattern of error response. In this regards it had been tested that for pattern effect the error score difference between ‘F’ (one of the eight cardinal number) versus ‘X’ (the next lesser value of the previous cardinal number, F) column value was ‘five’ as the value covers 95% confidence interval. Hence, the normative for pattern effect was ‘five’. Different error scores between right ear (first) and left ear (first) the cut off value ‘six’ covered a 95% confidence interval. Hence, the normative for ear effect was ‘six’. The error score difference between first spondee and second spondee the cut off value 12 covers 95% confidence interval. Hence, the normative for order effect was 12. The cut off value for reversal response was ‘two’ covers 95% confidence interval. Hence the normative for reversal was ‘two’.

Table- 7: “One sample Wilcoxon sign rank test” for Response errors of SSW test on normal listeners.

Participants Response Errors Wilcoxon statistic

P value. Interpretation

Normal60 (30 male and

30 female) native Bengali

Listeners

Pattern Effect 2.5 1 1>.05, Pattern Effect was not

present significantly

across normal participants.

Ear Effect 12 1 1>.05, Ear Effect was not

present significantly

across normal participants

Order Effect 0 1 1>.05, Order Effect was not

present significantly

across normal participants

Reversal 58.5 1 1>.05, Reversal Responses was

not present significantly

across normal participants

Hypotheses were computed regarding the objective was there would not be significant pattern effect, ear effect, order effect and reversal effect observed on SSW performance of normal native Bengali listeners. In order to prove the hypothesis as the responses were not distributed normally and distribution patterns were unknown non parametric test was performed for each condition that is one sample Wilcoxon sign rank test. Here Null

hypothesis for pattern effect was µ=5 (Pattern effect would not present significantly) against alternative hypothesis was µ> 5 (Pattern effect would be present significantly). Null hypothesis for ear effect was µ=6 (Ear effect would not present significantly) against alternative hypothesis was µ> 6 (Ear effect would be present significantly). Null hypothesis for order effect was µ=12 (Order effect would not be present significantly) against alternative hypothesis was µ>12 (Order effect would be present significantly). Null hypothesis for reversal response was µ=2 (Reversal responses would not present significantly) against alternative hypothesis was µ>2 (Reversal responses would be present significantly).

The next major concern was to investigate gender effect, whether the SSW scores would be significant between male versus female. The responses were assumed to be normally distributed. Hence, paired t-test was performed to draw the inference between gender differences.

Table: 8- “Paired t-test” and Comparison between C-SSW scores of Adult Male and Female normal native Bengali listeners:

t df P value

Interpretation

Adult male - Adult female

/-1.33/= 1.33

29 0.1935 0.1935> 0.05; Performance scores of Adult males and performance scores of adult females would not differ significantly.

Here, the null hypothesis was there were no significant difference on SSW test performance between male and female against alternative hypothesis was there was significant difference on SSW performance between male and female. Table-8 clearly depicted that the alternative hypothesis is rejected at α=0.05 level of significance (95% confidence level). t calculated value is -1.33. The modulus of that negative value should take i.e., positive value was considered. Therefore, t calculated value was 1.33, lesser than t tabulated value that was 2.0452 at degree of freedom (df) 29. As, tcal 1.33< ttab 2.0452 and also p > 0.05 hence, alternative hypothesis was rejected. Therefore, Performance scores of Adult males and performance scores of adult females would not differ significantly.

Then laterality effect was investigated, whether right ear performance and left ear performance would differ significantly or not. Responses were assumed to be normally distributed. Hence, paired sample t-test was performed to draw the inferences regarding laterality effect.

Here, the null hypothesis was there were no significant difference on SSW test performance between right ear and left ear of normal native Bengali listeners against alternative hypothesis was there was significant difference on SSW performance between right ear and left ear. Table-9 clearly depicted that the alternative hypothesis was rejected at α=0.05 level of significance (95% confidence level). t calculated value was 1.080. Therefore, t calculated value was 1.33 is lesser than t tabulated value that was 2.0010 at degree of freedom (df) 59. As, tcal 1.080< ttab 2.0010 and also p > 0.05 hence, alternative hypothesis was rejected. Therefore, Performance error scores of right ear and left ear of normal native Bengali Listeners would not differ significantly.

Table: 9- Paired Samples Test for Laterality Effect on SSW test of Right Ear Performance Error Scores and Left Ear Performance error Scores of Normal Native Bengali Listeners.

t df P Value InterpretationRight Ear

Performance Error Scores and Left Ear Performance

error Scores of Normal Native

Bengali Listeners

1.080 59 0.284 0.284>0.05;There would no

significant difference

between error scores of right ear and left ear performance

The typical errors on the performance of the SSW test of normal native Bengali listeners had been investigated. It represented here in the total sets of SSW words in which sets the participants performed well and in which sets they made more errors. Figure 8 represents a ‘Box Plot’ of the typical sets of words with respect to mean of errors in each item. Each set had separate mean which also varied individual to individual. But the values lied within a range. Therefore, based upon mean, maximum error score, minimum error score, 1st quartile and 3rd quartile value of all candidates in each set were distributed in the ‘Box Plot’.

Figure: 8- the Box Plot with respect to participants means quartile deviations with respect to each set.

The Box plot represented more errors on Set no.-1, 2, 3, 7, 10, 12, 15, 20, 23, and 24. The figure represented that all candidates’ performance error in each set ranged within lower and upper whisker but at set no. 3 one participant’s error response lied at extreme outlier value that is greater than to upper outer fence.

The SSW test was administered to 18 participants (9 males and 9 females) randomly selected from the original sample for second time, one week after the first test to measure the test retest reliability. The results were compared with the results obtained during the first test. For male, the Pearson moment correlation coefficient (r) was 0.88 and for female 0.92 suggested that there was a strongly positive correlation between test and retest trials. However, variation was observed in terms of the individual items on which errors were seen. This later findings probably indicated that individual made committed errors randomly on the test though his/her total errors score was constant.

SSW lists in Bangla were validated on six diagnosed native Bengali language learning disability (LLD) having age range 18-40yrs (Mean-24; Standard deviations- 1.2). Mean of C-SSW percentage was 54 and standard deviation was 3.30. In the validation the main objective was to investigate the performance of C-SSW error scores of normal native Bengali listeners as compared to performance of language learning disability listeners would significantly differ or not. Welch Two Sample t-test was performed as responses were assumed to be normally distributed and unequal sample size between two variables.

Table: 10 -“Welch Two Sample t-test” to compare the performance of C-SSW scores of normal native Bengali listeners and Language Learning Disability Listeners.

t df P Value Interpretation

Normal native Bengali listeners and Language Learning Disability Listeners

2.5706 5.062 0.03251 0.03<0.05; Performance scores of Normal native Bengali listeners and Language Learning Disability Listeners differed significantly

Table- 10 clearly depicted that the alternative hypothesis is accepted at α = 0.05 level of significance (95% confidence level), since p value is less than 0.05 (p < 0.05). Thus, the error scores obtained by disordered participants on the developed test were comparatively better than those obtained by the normal participants.

The final concern was to investigate response biases (pattern effect, ear effect, order effect and reversal) on Language learning disability participants. Response biases could not be judged on disorder population in order to present very less sample size and in presence of tie rank exact P value could not be obtained although the pattern of distributions were unknown. Hence, inferences could not be drawn regarding response biases of disorder population. A-SSW score was not taken into consideration as any site of lesion patient was not taken to judge the performance of SSW test in Bangla.

DISCUSSION

Bangla language is rich in rhyming and reduplicated words. Therefore, the performer might guess the word and the outcome might be over estimated. The more that one is

acquainted with the stimulus, the more readily one recognizes it (Lyregaard, 1997). Familiarity of a word depending upon listener’s exposure to that which in turns approximated by the frequency of occurrence of that word materials (e.g., literature, magazines). The most familiar words by means more high frequency words. Familiarity was also explained based on the effect of intelligibility. Prior knowledge of test vocabulary yields the threshold of the participants67. As the spondaic words were presented in staggered onset both in competing and in non competing situation, participants were likely to be missed out the competing word. Hence, familiar sets were taken rather familiarity weightage based on most familiar and most unfamiliar were excluded. Katz also had paired the familiar spondaic words through this assumption to increase the likelihood of the subject’s missing one or both competing words31. In Bangla language it is difficult to get bisyllabic words have equal stress on both syllables. In standard Bangla language, stress is predominantly present at initial syllable of the word16, while secondary stress often falls on all odd numbered syllable16 thereafter, giving syllable string such as /ʃɔm-bɔɽ-dho-ni-o/ ‘cultivation’, where boldface represents primary and secondary stress. The first syllable carries the greatest stress, with the third carrying a somewhat weaker stress, and all following odd-numbered syllables carrying very weak stress. However, when words were borrowed from Sanskrit, the root syllable has stress, out of harmony with the situation with native Bangla words16. Adding prefixes to the root word typically shift the stress to the left; for example while the word / ʃɔmbhɔb/ means ‘possible’ carries the primary stress on the first syllable /ʃɔm/, adding the negative prefix /ɔ/ creates /ɔʃɔmbhɔb/ means ‘impossible’, where as the primary stress is now on the newly added first syllable /ɔ/. In any case, Word stress does not alter the meaning of a word, and always subsidiary to sentence-stress16. Thus it is cleared that in Bangla language true spondee words are not available. The talker has to present bisyllabic word with equal stress on both the syllable in defining spondee words. Linguist has considered compound word as bisyllabic word having equal stress perceptually because process of compounding brings several words into a single system of accentuation. Thus, the uniformity in accentuation becomes responsible for bringing ease in pronunciation of compounds, which is hardly available in sentences21. Judgement of homogeneous stress pattern was judged through spectrograph70. They had judged acoustic properties of speech stimuli especially for spondee words in order to measure auditory thresholds. They judged pressure waveform, variation of sound pressure that occurs with time and intensity level of steady state speech signal having highly variable sound pressure level.

In this study the erroraneous raw SSW score was given less importance. Because, the raw SSW error score might be contaminated by peripheral distortion31. But the test aimed to quantify the patient’s difficulty at the central level. As a consequence, the corrected SSW score would be able to judge the performance at central level by reducing the peripheral distortion, might present within the raw error score.

However, from the present investigation total mean C-SSW error score for male was 16.03% and in female 12.83%. There was a supportive findings incorporated by the preparation of SSW tape using 24 sets of Spondaic words to standardize in Indian population on 60 normal hearing Indian listeners (30 male and 30 female, age range 16-29 years). The mean C-SSW error score of this investigation were for 15.25% in females and 13.27% for males15. In this investigation knowledge of 1st language and 2nd language exposures were not taken into consideration. But an important fact that for a learning process, the listener’s selected input structure should be transferred and remodelled as they progress in the development of their linguistic knowledge across the languages. Therefore in the process of production, the transfer process is involved of the learner’s retrieval of this knowledge and in

their effort to bridge those gaps linguistically based on their knowledge which cannot be side-stepped by avoidance 39. In the current investigation the participants educational background of where had till XIIth standard Bangla as 1st language and English as 2nd language. But at graduate level participants had English as first language and Bangla as second language. Therefore as per previous explanation of learning the error score might vary with respect to present status of linguistic knowledge where as the materials were collected from magazine, news papers.

During the qualitative analysis the normative was found for ‘pattern effect’ was ‘five’ was supported by Katz’s study31 where pattern effect was not found significantly on normal individuals. Pattern effects represented the highest amount of mistakes occurring in the second word, both when the test began in the left ear as well as in the right ear respectively52. Qualitatively pattern effect represents the integration disorder. As per Buffalo model37 on SSW test, patter effect might have significantly present in which the left competing condition for the left-ear-first items was significantly poorer than any other columns (especially in right-handed individuals). The lesion involved for pattern effect was tumor in Corpus Callosum 36.

The normative found for ‘Ear Effect’ was ‘six’. Ear performance was generally a more accurate indicator of central auditory function that either the SSW conditions or total score31. Defective performance in one ear suggested the dysfunction in contralateral hemisphere. However, ear effect were absent in normal listeners on SSW test. There was another investigation done on 86 normal listeners where mean C-SSW was consistent with Katz’s findings31 and also there were no prevalent Ear effect3. So present study finding were consistent with these supportive studies.

The normative for ‘order effect’ was ‘12’ which was quite greater in the current investigation rather the English SSW word test31 where it was ‘five’. In English language when spondaic words were paired it did not follow any phonetic content31. Through acoustic analysis the physical properties of spondees along with its homogeneity was judged 70. In Bangla language there was no true spondaic words; attempt had to be made in order to produce stress in both the syllable. Therefore, when the two words were paired, as these did not follow phonetic content, the acoustic properties of these two spondaic words might vary with respect to homogeneity in terms of frequency, intensity and time. As their physical properties of these two spondaic words might differ the outcome also might differ in terms of detectability and intelligibility. If the spondaic words were homogeneous with respect to recognition, then each word would become recognizable. Also familiarity is an important factor in determining degree of intelligibility. Better performance is achieved when the performer knows the stimulus materials for which he/she is listening67. There were two steps of familiarity measures. The first was how familiar the individual is in general with the target word i.e., the more the listener uses the target word, the more familiar with it. The second was whether or not the listener knew that the target word was a member of the same set of test items. Based upon this concept it might be judged that Bangla SSW words were rated based upon each set where each set consisted of two paired bisyllabic words and its staggered bisyllabic words. Therefore, each paired word set each bisyllabic word might have different familiarity levels. Suppose, one word was rated most familiar another word was rated doubtful. Therefore, for that particular set in between two paired spondaic words itself heterogeneous. Again, the single syllable of words was presented in competing manner that was on complex situation. For these reasons the score might differ. In English language, in order to make SSW EC-list and ED-list spondees were taken and paired where each spondaic

word had separate familiarity31. But in Bangla language, an average familiarity of the each set was computed including all words, rather separate word in the set. Therefore, heterogeneity in terms of acoustic properties of two paired spondee words and familiarity the score between 1st spondee and 2nd spondee error score might have more difference. If 1st spondee had more errors than the 2nd it was Order High/Low (first spondee more errors than second spondee) and vice versa. Order Effect High/Low was that when subtraction might give a positive value because the 1st spondee might have more errors than the 2nd 52. According to Buffalo model37

qualitatively order effect High/Low represents tolerance fading memory and Low/High represents decoding function. Tolerance Fading Memory signs were associated with anterior portion of the brain 23, 41; therefore, the connection among them might be anatomical. Anatomically, phonemic decoding of speech was uniquely associated with the auditory cortex of the brain. The middle-posterior portion of the superior temporal lobe was responsible for phonemic discrimination, phonemic memory, and phonemic synthesis-analysis40, 41. In the current investigation order effect would not differ significantly among normal listeners. The result of the current investigation was supported by Katz’s findings31 and Arnst study3.

Reversal response revealed the phoneme sequencing. Reversal might present as one or might be absent31. Present investigation finding regarding reversal response was supported by Arnst study3. According to Buffalo model37qualitatively it analysed the phoneme organization. Auditory sequencing error lesion is located in fronto-temporal and fronto-temporo-parietal regions41, 23.

The findings regarding gender effect was supported by Chandrasekhar’s study15. A part from findings of dichotic listening test there was an investigation to establish the normative on adults and children10. In adult’s score there was no significant difference between genders. So, the current investigation finding was supported by this study finding regarding gender effect on dichotic test.

The findings regarding laterality effect was supported by Katz’s study31. There was

another SSW test which was developed in French version 56 French version of SSW had also got similar findings like this investigation. The SSW is essentially free from laterality effect caused by the hemispheric dominance in terms of speech 56.

In the current investigation few typical error were observed. When Katz finalized the 40 items clinical version of SSW list EC 31, he found that in some sets the rate of error was high for normal and also they appeared relatively unfamiliar. Participants had greater difficulty on some items. Probably this was either due to the improbable nature of these words appearing on a test such as these, or indeed the words might not be appeared in the vocabulary of the subjects 68. Familiar word retrieves faster 22 and less familiar word become fade out 57.

3 24 2 1 20 15 27 40 11 5 21 38 19 34 13 6 37 28 31 80

5

10

15

20

25

30

35

40

45

50

45444341

38

29

2420

171615151414131211109 8 86 6 6 5 5 4 4 3 3 3 2 2 2 1 1 1 1 0 0

Total Error

Set Number

No.

of E

rror

s per

Item

Figure: 9- Item wise total error in descending order.

However, these responses would be explained since they probably differ qualitatively from other types of responses. These typical responses probably indicated that prior knowledge of lexical, semantic and syntactic rules of the language, which has influenced their performance. The SSW items were probable ‘complex linguistic context’ since the listener would be getting speech stimuli in a time sequence which staggered the words that were being presented. Hence, the performance in this complex linguistic context might be influenced by the abstractions of the linguistic rules on the part of the listener. Top-down processing of language 20, 46 had confronted with the recipient’s former knowledge and expectations facilitate comprehension and made influences on target stimuli. Any act of perception is intimately tied up with perceiver’s background i.e., the anterior experience, their memory and their attitudes 44. Again the typical error pattern might occur due to presence of heterogeneity in terms of dissimilar acoustic properties of two paired words70. Same thing might be explained by ‘Analysis by Synthesis’ model63. This model represented a process of specifying an unknown sign in terms of the best match selection from a standard inventory; it might be possible to explain these unique error responses observed in the normal Bengali listeners in the present investigation.

A part from test retest reliability there was strongly positive correlation. This finding was supported by Chandrasekhar study15 However, variation was seen in terms of the individual items on which errors were seen. This later findings probably indicated that individual made committed errors randomly on the test though his/her total errors score was constant. In the supported study also scores were consistent but the item errors were varied. This study was also performed on Indian context.

A test’s validity varies according to the purpose for which its results are used and the types of individuals tested. The mean C-SSW error score was 54% and standard deviation was 3.30 for Bengali Language learning disability listener. This value should not be taken as a norm of Adult language learning disability because the sample size was so less and heterogeneous in terms of variability like first patient was diagnosed as auditory neuropathy,

others were diagnosed as dyslexia in terms language learning disability but whether it was dysphonetic or dysedietic were not ruled out. The chief characteristic of dyslexia in adulthood is difficulty with reading. A dyslexic adult may be slightly slow in reading but otherwise competent. The chief characteristics of dyslexia in adulthood are usually weaknesses in auditory short-term memory (working memory) and visual processing skills47. There was an experimental short form of SSW test on 40 learning disability subjects including male and female with age range 7-11 years along with age matched peers 73. The normative obtained for learning disabled subject at 7 years 25.16% with standard deviation 10.50%, at 8years 25.6% and standard deviation 10.50%, at 9 years 15.58% with standard deviation 10.50 %, at 10 years 8.21 % with standard deviation 10.50% and at 11yrs 13.25% with standard deviation 10.50%. Although the normative values did not support the current investigation but the e study had also mentioned that when they were considering individual score the error scores were more with respect to the normative in presence of wide range of standard deviations. In this point of view individual scores would be discussed along with response biases.

Table: 11- The individual performance of six adult LLD patients on SSW test

Patient’s Serial No.

C-SSW Score

Pattern Effect

Ear Effect Order Effect Reversal

1. 113 Insignificant Significant Significant Absent

2. 46 Insignificant Insignificant Insignificant Absent

3. 23 Significant Insignificant Insignificant Absent

4. 25 Significant Insignificant Insignificant Significant

5. 52 Insignificant Insignificant Significant Significant

6. 65 Significant Insignificant Insignificant Insignificant

It was discussed that LLD subject no. 1 had been diagnosed as Auditory Neuropathy Spectrum Disorder. A rare but severe form of CAPD called auditory neuropathy74. Individuals with auditory neuropathy have normal cochlear function, usually identified by otoacoustic emission tests, but have abnormal auditory brainstem responses. Therefore, the C-SSW error score has matched with the statement. The client was also having significantly ear effect (High/Low) and order effect (Low/High). Both of the findings related to ear and order effect suggestive of affected decoding function with respect to Buffalo Model 37. Anatomically, phonemic decoding of speech is uniquely associated with the auditory cortex of the brain. The middle-posterior portion of the superior temporal lobe was responsible for phonemic discrimination, phonemic memory, and phonemic synthesis-analysis40, 41. Lesions to this region of the brain demonstrated large error peaks on the SSW test in the contralateral ear 30, as well as significantly greater number of errors at the end items compared to the beginning (i.e., Order Effect low/high) 71, 45.  The indicator might be associated with slow processing, as seen in those with auditory decoding problems. Similar findings were noted in other types of speech analyses 11, 64.

Pattern effect was significant for LLD subject 3, 4 and 6. Qualitatively pattern effects represented the integration function as per Buffalo Model 37. The lesion associated to pattern

effect is corpus callosum 35. Pattern effect was commonly seen in those with severe reading and/or spelling problems and who are sometimes labelled Dyslexic34.

LLD subject 5 had significant order effect (High/Low) along with significant numbers of reversal responses. Therefore, qualitatively these were the indication of tolerance fading memory as well as organization problem as per Buffalo Model 37.  The word "tolerance" refers to understanding speech in noise and "fading memory" refers to auditory short-term or working memory. "Various" related characteristics such as attention66 are also combined into the TFM category. These appeared to be no functional connection between these factors. However, blocking out noise, short-term/working auditory memory, attention, and other TFM signs are associated with anterior portion of the brain23, 40 therefore, the connection among them might be anatomical. Order Effect high/low is associated with limited short-term memory (a primacy error) 34.

LLD subject 2 had only increased C-SSW error score might be in presence of dysphonetic dyslexia where other response biases were absent significantly. The poor readers have difficulty detecting rapidly presented acoustic changes as complex condition 64 14, 26, 19.

The final major concern was whether the performance of C-SSW scores differs significantly between normal and language learning disability listeners. The performance of normal listeners and language learning disability listeners would differ significantly. The finding was supported by Young’s study73. It was an experimental short form of SSW test on 40 learning disability subjects including male and female with age range 7-11 years along with age matched peers. In the study normal age matched control group and experimental group performance differed significantly. Another study was performed in 93 normally achieving children and 97 children referred to a learning disabilities clinic9. All subjects were 8-11 years of age. The SSW test was found to differentiate between the normally achieving children and those experiencing classroom learning difficulties. Further, it was found that the performance of the normally achieving group was generally better than current test norms would imply. 

Therefore, from the current investigation for experimental group individual performance could compared both qualitatively and quantitavely. But statistically qualitative responses could not be judged on disorder population in order to presence very less sample size and in presence of tie rank exact P value could not be obtained although the pattern of distributions was unknown. Hence, inferences could not be drawn regarding response biases of disorder population. Further study by increasing sample size will be able to draw a conclusion regarding the facts.

In the current investigation A-SSW was not taken into consideration because, any site of lesion cases was not taken where hemispheric asymmetry might be observed along with problem in central auditory processing.

CONCLUSION

The SSW is an efficient, reliable and valid tool to be used among native Bengali speakers between the age ranges of 18-40 Years in order to detect Central Auditory Processing Disorder. The test may also provide qualitative informations about the presence of central non auditory dysfunction. It may also be included as a part of routine speech test to differentiate cochlear and retrocochlear pathology. Same study can be used for development of speech perception research materials. It will further enrich the field of Audiology.

Limitations of the Study

1. Less number of sample sizes in order to establish a normative and to validate disorder population such as Learning Disability.

2. To develop a more valid tool few heterogeneous stimulus pattern may be excluded from the final list.

3. Qualitative analysis is not inferential into the study to establish disorder norms.

Future Directions

1. Measurement procedure of adjusted score in SSW test may be further studied to confirm the site of lesion and the amount of (C) APD.

2. SSW test material may be further developed and standardized in other Indian languages.

3. The study may be incorporated to see the therapeutic improvement in adverse listening condition for (C) APD and that may formulate a prognostic matrix.

4. SSW test performance in normal listeners and in different (C) APD subjects may be further validated with the help of f-MRI or other advanced radiological studies can pinpoint the site of lesion.

5. Practice effect study on SSW test may be further documented as an evidence of understanding of adaptive learning.

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