Running head: ARTICLE CRITIQUE 1
Quantitative Intervention Article Critique
Allyssa Farris
The University of Akron
ARTICLE CRITIQUE 2
Quantitative Intervention Article Critique
Logemann, J. A., Rademaker, A., Pauloski, B. R., Kelly, A., Stangl-McBreen, C., Antinoja, J.,
Grande, B., Farquharson, J., Kern, M., Easterling, C., & Shaker, R. (2009). A randomized
study comparing the shaker exercise with traditional therapy: A preliminary
study. Dysphagia, 24, 403-411. doi: 10.1007/s00455-009-9217-0
Introduction
Problem Statement
Since the field of speech-language pathology began to shift focus more on the evaluation
and intervention of swallowing disorders, several studies have been completed examining the
effectiveness of the Shaker exercise. In previous studies, this intervention method has been
utilized on specific, convenience populations usually obtained from a single institution. This
study explored the next step in providing evidence to the efficacious nature of the Shaker
exercise by comparing this intervention to traditional swallowing therapy and completing a
randomized clinical trial involving participants from numerous institutions.
Significance.
Dysphagia is a fairly new disorder remediated in speech-language pathology.
Articulation and language disorders, for years, have been the bread and butter, so to speak, of
this field. As the scope of practice has extended to include the diagnoses and intervention of
swallowing disorders it has become essential for studies to evaluate the effectiveness of
intervention strategies. Evidence-based practice that combines clinical judgment, client
preferences, and research is imperative to making sound clinical decisions to support the
individual needs of each client. Further research in swallowing disorders is crucial in providing
clinicians with empirically supported, best practices to implement into their therapy sessions
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with clients who have swallowing disorders. Moreover, swallowing intervention tends to be one
less academically emphasized in undergraduate and graduate programs, only increasing the need
for empirically supported interventions to guide clinical decisions. Additionally, using a
randomized sample from multiple institutions improves the ability to generalize results found
within a study. This study compares two well-known swallowing interventions in an attempt to
illuminate the most efficacious intervention in a way that has the most ability to generalize to the
general population.
Literature Review
This study highlights a need to assess the Shaker exercise in a randomized clinical trial.
It is therefore important to understand what the Shaker exercise is and what it attempts to
alleviate. At the beginning of this article, the researchers discussed factors affecting the opening
of the upper esophageal sphincter (UES). In various studies, the hyoid was found to lift the
larynx and pull the UES open when it moves anteriorly and superiorly during a swallow. The
researchers report the Shaker exercise is based on that specific anterior, superior motion of the
hyoid that results in the contraction of numerous extrinsic laryngeal muscles. The Shaker
exercise is comprised of isometric and isotonic exercises used to strengthen these extrinsic
muscles in order to increase the size of the UES opening.
Additionally, the researchers vaguely discuss previous research related to the Shaker
exercise. The researchers reported that over the years there have been a number of studies
appraising the validity of the Shaker exercise. However, in this literature review, the researchers
only outlined two studies. One study evaluated this intervention on an elderly population;
another study assessed this intervention on a tube-fed population. In all cases expressed in this
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article, the studies resulted in a wider UES opening. The researchers provided a list of references
consisting of twenty published articles.
Client Description and Justification
Currently, there are many more than just one client on caseload at my externship
placement that could benefit from an empirically supported swallowing exercise. This semester I
am placed at a rehabilitation and long term care facility whose primary clients are those with
psychiatric disorders. Due to the nature of their illnesses, most of the clients living at this facility
are prescribed heavy antipsychotic medications to diminish many of the symptoms of
schizophrenia, bipolar disorder, and personality disorders. Unfortunately, many of the
medications prescribed negatively affect the swallowing mechanism. Because a number of these
clients are weaned on and off of medications throughout the year, many of them come and go on
the caseload. At this time, I have six swallowing clients that are seen three-five times a week
who have oropharyngeal dysphagia due to medication interference or stroke.
I strategically chose an article that sought participants who experienced oropharyngeal
dysphagia. Luckily, the participants also experienced prolonged aspiration, which is one of the
criteria used to refer clients to the rehab team at my facility. This article was chosen to validate
or deny the efficacy of the Shaker exercise on oropharyngeal dysphagia, and to therefore help
guide my choice of intervention strategies.
Research Question
According to Logemann et al. (2009), “Our trial compared the Shaker exercise with
traditional swallowing therapy to determine if either treatment is better at reducing aspiration and
improving swallow function in patients with documented aspiration” (p. 404). This statement
does not explicitly define a hypothesis or research question; however, it does enable one to be
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inferred. From the quoted statement, the inferred research question is: Does the Shaker exercise
result in a greater reduction of aspiration and increase in swallowing function than traditional
swallowing therapy?
Methods
Participants
Demographic characteristics were expressed in a table that reported gender, race,
education level, diagnosis, and presence or absence of a feeding tube. All participants, even the
five who did not complete the study, were depicted in the table. The researchers reported, in the
results, that no significant differences were found between the two groups in respect to these
demographic characteristics. However, I saw some differences in the groups that pointed to
discrepancies in group equivalence. For example, the age ranges for the two groups were
significantly different. The group who received the Shaker intervention ranged in ages from 26-
84, while the group who received the traditional therapy ranged from 56-81. Practically
speaking those age ranges are substantially different with one group having individuals thirty
years younger than the youngest in the comparison group. Additionally the traditional group had
three more participants than the Shaker group.
According to the researchers, this study invited individuals from seven different
institutions to participate. These institutions included: Evanston Northwestern Healthcare,
Froedtert Hospital, H. Lee Moffitt Cancer Center, Northwestern University, St. Joseph’s Hospital
of Atlanta, St. Joseph Regional Medical Center, and Walter Reed Army Medical Center. The
researchers reported that all participants were randomly assigned to either the Shaker group or
the traditional therapy group. To randomly assigned and manage data collected, the research
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group utilized The American Speech Language and Hearing Association’s Communication
Sciences and Disorders Research Group. This group is located in Rockville, Maryland.
Participants were invited to join this study only after meeting a specific set of five criteria
points. The first inclusion criterion dictated the type of dysphagia, time since onset, and
causation of dysphagia. Patients were required to have oropharyngeal dysphagia of at least three
months post onset due to stroke or neck and head cancer. Some combination of post and pre
swallowing aspiration and inadequate UES opening was the second criterion used to qualify
participants. The third was residue present during videofluorography in the pyriform sinuses or
in the valleculae. Each participant needed a documented aspiration period of at least three
months. The fifth, and last, criterion was compliance to exercises and session attendance. The
19 individuals, from seven institutions, who were invited to participate in the study meet the
criteria listed above and did not meet any of the exclusion criteria which included: surgery to
extrinsic laryngeal muscles, cognitive deficits, alcoholic neuropathy, inability to carryout
exercises due to muscle atrophy, paresis, or paralysis, consumption of specific anticholinergics,
absent pharyngeal swallow, aspiration while swallowing, and neuromuscular disorders.
Participant Sampling and Limitations.
Given the previous studies completed, the researchers saw a need to evaluate the Shaker
exercise on participants from numerous institutions. The research team however did not
explicitly define the method they used for determining eligibility of institution. It is implied that
the institution where chosen at random. Vaguely describing the research sampling method leads
to discrepancies in the replication of this study and decreases the ability to generalize the results
of this study to other environments and populations.
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In order to participant in this study, patients were required to meet a list of inclusion
criteria. On this list was oropharyngeal dysphagia due to head and neck cancer or stroke.
Participants were stratified first by etiology and then randomly assigned to one of two
conditions. Each group was therefore equivalent, each having individuals from both strata.
Restricting the sample to only head and neck cancer or stroke patients dampens the ability to
generalize results to the greater population of individuals with oropharyngeal dysphagia.
However, this restriction does aid in decreasing the number of internal threats to validity.
Setting and Limitations
The research team provided little information in regards to the setting where the
interventions took place. From the description of the interventions, it can be assumed that the
interventions took place in each institution where the patients took residency. It is unclear;
however, where in each institution (therapy room, hallway, common areas, personal room, etc.)
the intervention was conducted. When the research study’s settings are not explicitly described,
it is difficult to create replication studies used to assess the validity and reliability of the study’s
results. Additionally, it becomes difficult for clinicians to determine which settings the
intervention’s results would generalize to.
Research Design
This true experimental research study utilized a pretest-posttest control group design.
The presence of a comparison group, acting as a control group, where both conditions are
manipulated by researchers and the utilization of random selection to ensure group equivalency
makes this research study a true experimental design. The participants were stratified based on
etiology of oropharyngeal dysphagia and then randomly assigned into two therapy groups. The
ARTICLE CRITIQUE 8
study was comprised of two therapy groups; the Shaker exercise group and the traditional
therapy comparison group.
Research Design Limitations.
While the pretest administered at the commencement of this study helped ensure group
equivalency and provided baseline data to compare results to at the end of the study, the nature
of the pretest-posttest control group design leads to some limitations. In general, experimental
designs with a pretest can have issues with the pretest affecting the measurement of the
dependent variable at the posttest. For this study; however, each participant underwent a
modified barium swallow study at the beginning at end of the study. This is not the type of
evaluation that can be easily influenced by the participants; a person cannot easily influence the
trigger of their swallow to show a regression or progression of results. Moreover, the researchers
only gave one pretest at the end of the intervention period. Administering a posttest directly at
the end of the study shows immediate progress made due to the implementation of the
independent variable; however, it does not illuminate long term results. Generalizations about
the duration of time the independent variable continues to affect the dependent variable after the
independent variable has been withdrawn cannot be made without more posttests. To increase
the ability to generalize the results of this study, more posttests should’ve been conducted after
the withdrawal of the independent variable.
Implementation of Research Design
Group Descriptions and Limitations.
This experimental design used two conditions: a Shaker exercise group and a traditional
therapy group. Within the description section of these two therapies, each condition was
described. The Shaker group did three 1-minute head lefts followed by thirty consecutive
ARTICLE CRITIQUE 9
repetitions of head raises. While the description of the actual exercise is thorough, the
description did not explicitly report how many total repetitions were done and how frequently
this exercise was repeated throughout the day. The traditional therapy group did a regiment of
exercises including the super-supraglottic swallow, the Mendelsohn Maneuver, tongue base
exercises, extended yawning, and a number of tongue retraction exercises. While this
description included the number of minutes each person completed the exercises, it did not report
how many repetitions of each exercise was completed or how the five minutes were broken
down among all the exercises done in the traditional therapy group. The researchers did well in
explaining the exercises used in each therapy group; however, they did not fully report the
precise amount of time spent on each exercise each day. Additionally, the researchers disclosed
how many days a week the interventions were implemented; however, they did not say what time
of day or where the interventions occurred. Without that absolute depiction replication studies
cannot be conducted. Replication studies increase the ability to generalize the study’s results,
which provides strength to the validity of the intervention.
Data Collection.
The data collection methods used at pretest were clearly reported. Before the
introduction of the independent variable, each participant underwent a modified barium swallow
study. During this evaluation, each patient swallowed liquid barium in the amount of 3ml and
5ml. This was done twice. Additionally, each patient swallowed a single 5ml bolus of barium
pudding. The results of each participant’s videofluoroscopic study were recorded and sent out,
to a laboratory taking no other part in the study, for analyzing. The videos were masked and
reviewed by two blinded analysts. Additionally, the videos were converted to digital copies so a
computer could analyze each video for anterior and superior hyoid movement, anterior and
ARTICLE CRITIQUE 10
superior laryngeal movement, and the width of the UES viewed both anteriorly and laterally. The
presence of aspiration and the occurrence of residue within the swallowing mechanism were
monitored. At posttest, the pretest data collection methods were replicated. The researchers
evaluated each participant in the same way, using the same tools post intervention as they did
pre-intervention. Again, the researchers thoroughly described this process and the tools used to
collect data on the dependent variable.
Limitations
Although the majority of the data collection section of the article was well described,
there were a couple discrepancies with who was doing the observing and data collection. For
example, the researchers did not clearly report who performed the barium swallow studies, and
their level of competency and training. Different clinicians conducting the study might have
more training and experience giving the study and therefore inadvertently affect the dependent
variable measurements. Likewise, it is unclear how many individuals observed the videos and
how their results were compared. In one section two blinded analysts were described and in a
different section it was briefly reported the observations of the analysts were compared with the
results of the clinicians. These small discrepancies would make it slightly more difficult to
replicate this study without contacting the research team to gather further, concrete descriptions
of the data collection.
Dependent variables
The dependent variables in this study were the reduction of aspiration and the general
improvement of swallowing in participants who have a documented history of aspiration. In the
most basic terms, diminishing aspiration was the dependent variable. Many measurements were
taken to show the decrease in aspiration and the increase in swallowing functions. These
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measurements include: presence or absence of aspiration and pharyngeal residue, the anterior
and superior movement of the hyoid, the anterior and superior movements of the larynx, and the
width of the UES opening.
Measurement of Dependent Variables.
The changes in the dependent variables were measured several different ways. A
modified barium swallow study was conducted pre and posttreatment. This instrument was used
to measure the occurrence of aspiration during any phase of the swallow and the presence of
residue in the swallowing mechanism. Data was collected through observations of the videos.
Two blinded analysts reviewed the tapes, as well as, the participating clinicians; however, it is
uncertain at what points in time or in what manner their observations were recorded and
compared. This data was displayed in a table using nominal level data. This measurement noted
if there was or was not a presence of aspiration before, during, or after the swallow. The videos
where then digitized where in which a computer program analyzed the elevation and movement
of the larynx, hyoid, and the opening functions of the UES. Specifically, the programs that were
listed but not described were used to measure the width of the UES opening anteriorly and
laterally, anterior and superior hyoid movements, and anterior and superior larynx movements.
The computerized analyzing program measured those components in centimeters. These ratio
level data were then displayed along with descriptive statistics in a table. Lastly, The
Performance Status Scale for Diet was used and discussed; however, the researchers do not
specifically define this scale, describe how it was used, or what data is measured.
Instrumentation and Limitations
This study utilized different instruments and observations to obtain data on the dependent
variable. The first was the equipment used for the barium swallow studies (videofluroscopic
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evaluations). No information was given on their calibration. The article notes that each
participant’s videos were saved on a protected computer. These videos were digitized and every
third image for each patient was evaluated using a computer analysis program. The researchers
do not explain the program’s name, how it works, or who tranfered the data. It is unclear that
person(s) level of involvement or knowledge of the study. The article does report that the
measurements, although it’s unclear exactly which measurements are being discussed, were
calibrated using the penny’s diameter of 1.78 cm. Previous knowledge of this calibration
instrument or measurement is assumed. Furthermore, this study reported the two individuals
evaluating the videotapes were blinded; however, the study did not explain their training or
experience level. It is assumed the analysts are competently in evaluating larynx and hyoid
movement and the UES opening. Moreover, another assumption made is that the radiologists
running the equipment during the videofluoroscopic evaluations were unbiased and consistent
across participants. While the images used for data collection were described in detail, the
researchers did not report how many radiologists were used and what information they were
given about the study and the study’s hypothesis. Due to the lack of information revealed
regarding the instrumentation used during this study, the instruments are assumed to have
collected valid and reliable measurements of the dependent variable but without more
information this cannot be substantiated.
Validity and Reliability
In an attempt to obtain reliable data, the researchers utilized two blinded analysts. These
analysts reviewed and assessed the videos of the videofluoroscopic studies. Using blinded
analysts helped maintain integrity throughout the study. Additionally, the videos they were
observing were masked. The analysts did not know which results belong to what participants or
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what intervention group. Therefore, interobserver reliability was used as a consistency measure
to help ensure reliability of the dependent variable measurements. Moreover, in the results
section of this article the observations of the participating clinicians are discussed. The
researchers reported their observations were confirmed by the research analysts, adding another
layer of reliability
Internal Threats to Validity
When evaluating this research study, there are a few potential threats to internal validity
that should be addressed. The first, attrition, is highly applicable. This study had a very limited
number of participants to begin with, far less than originally planned, and five patients were not
included in the posttreatment data tables. According to the article, two participants in the
traditional therapy group did have the final barium swallow study done at completion of the
intervention phase, while three participants in the Shaker exercise group did not have the study
completed. Consequently, this was a dropout rate of 26%. Some confidence in group
equivalency is lost with that high of a percentage of attrition. Statistical analysis were done and
briefly and ambiguously described in an attempt to combat this threat.
Additionally, history could have also been an internal threat to validity present in this
study. It is assumes, although no specifically noted, that the individuals participating in this
study traveled to and from the clinics involved in the study. Therefore, events occurring in their
homes between the pretest and posttest measures of the dependent variable could have affected
the data collected. The researchers collected data on the amount of time the participants
practiced strategies outside of the clinics. The Shaker group practiced a median of 792 minutes
while the traditional group practiced a median of 1079 minutes. Even such slight differences can
affect how the participants respond to the independent variable.
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Instrumentation is another internal threat to validity that might have been present. Many
different methods of data collection were used during this study. Radiologist, either with or
without the presence of participating speech pathologists, completed the barium swallow studies.
It was not reported if the machinery used was recently and appropriately calibrated before each
series of testing occurred. They attempted to combat this threat by ensuring each participant’s
video expressed a certain number of images showing anatomical structures during the swallow.
Additionally, a computer program was used to measure the distance of movement of the UES
opening, the larynx, and the hyoid. While the article discussed the measurements of every third
picture being calibrated, no context is given. It is not clear what that calibration is referring to
and what impact that makes on this internal threat to validity.
External Threats to Validity
It is difficult to evaluate internal threats to validity without discussing external threats to
validity; there are a few potential threats to internal validity present in this study. Novelty is one
possible threat to external validity. This study was conducted in a fairly short time frame which
helped to combat history and maturation; however, it can contribute to the novelty effect
meaning the dependent variable measurements were a result of a new intervention. Additionally,
more potential external threats to validity include: experimenter, interaction of history and
treatment, and the interaction of time and measurement of the dependent variable. At each
institution that participated in the study, a speech pathologist implemented the two interventions.
The subtle differences in each clinician might have affected how the participants responded to
the independent variable. This study attempted to combat this threat by explicitly training the
therapists in each intervention. As previously discussed, events occurring outside the clinic may
ARTICLE CRITIQUE 15
impact how each participant responds to the independent variable. The short duration of the
study naturally attempted to combat this threat; however, the implementation of more posttests
would have addressed this threat as well as the interaction of time and the dependent variable
measurement. Measurements of the dependent variable were taken only directly following the
end of the interventions. This greatly limits the ability to determine the long term effects of the
independent variables. More posttests could have more confidently shown the effects of the
independent variable over time.
Results
The majority of the results are clearly displayed in tables. The nominal level data used to denote
the presence or absence of aspiration is represented in the article’s second table. In the table, the
number of participants who demonstrated aspiration before, during, or after the swallow for each
intervention group was shown. The same format was used to show oral and pharyngeal residue
in all participants for both intervention groups. The physical representation of the data collected
was clear and apparent. The ambiguous results relate to the Performance Status Diet Scale that
was used to measure residue in the oral cavity and pharyngeal cavity. The researchers did not
explicitly describe this scale, the exact data obtained from this measurement, or the implications
of the data found from this measurement.
Descriptive Statistics
Descriptive statistics were used to report six measurements within the larynx. These
behaviors were used to evaluate how each condition impacted the participants’ abilities to
swallow. The graph displayed each of the six behaviors, the size of the movement measured in
centimeters for both pre and posttests, the standard deviation, as well as, the mean of the
movement distance. The mean and standard deviation are the descriptive statistics reported as
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measurements of the dependent variable. These statistics are appropriate given the ratio data
level used to describe these behaviors.
Effect Size and Limitations
This study did not explicitly report any effect sizes. Given the data provided in the
tables, a clinician could independently determine the effect sizes; however, the researchers did
not clearly provide them. Effect size describes the magnitude of the change seen on the
dependent variable as a result of the intervention introduced. This magnitude provides insight to
the practical significance associated with the implementation of the independent variable. The
researchers did not clearly state the effect size, and therefore does not provide a clearly defined
practical significance. The absence of this information begs to question whether the researchers
did not explicitly state it due to an unfavorable or small overall effect size.
Statistical Significance
This study utilized many different measurements of statistical analysis. The Fisher’s
exact test was used to compare patient characteristics of both groups, the Wilcoxon Rank Sum
Test was used to compare minutes practiced and change in diet, and the McNemar’s test was
used to compare dichotomous results between groups. The researchers did not explain the tests
used, the results from the measurements, or why those measurements were chosen. Additionally,
the article reported that the ANOVA was used to analyze the barium swallow studies, and t tests
were used to analyze pre and post treatment measurements within groups and between groups. A
prevalent limitation of the reporting of the statistical significance is the vaguely described tests
used to analyze the data. The researchers relied heavily on assumptions during the description of
this section.
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In terms of aspiration and residue, little to no statistical significance was found within
groups and between groups. As the graph below demonstrates, the only significant difference
between groups was the aspiration at post-swallow with a p-value of .028; however, the p-value
for the traditional group could not be tested thus calling into question the validity of this
difference measurement. Additionally, for swallowing the idea significance value would be less
than .02. Total oral and pharyngeal residue measured pre and post treatment displayed no
statistical significance between groups or within groups.
While referring to the hyoid, UES opening, and larynx measurements, a few increases
were noted in the traditional therapy group. The superior laryngeal movement with a p-value of
.009, the superior hyoid movement with a p-value of .044, and the anterior laryngeal movement
with a p-value of 0.026 demonstrate a significant difference if using the general communication
disorders standard of .05 to show significance. However, if using the dysphagia standard of .02,
only one value truly shows significance. Both therapies showed statistical significance of the
UES opening width; the Shaker’s p-value being .015 and the traditional therapy’s p-value being
.023. Aside from post-swallow aspiration, no statistical significance was determined between
groups for any of the dependent variable measurements.
Behavior Measured Shaker Exercises (p values) Traditional Therapy (p values) P Value
Between
Groups
Aspiration-
Preswallow
.32; not significant .32; not significant 0.99; not
significant
Aspiration-
Intraswallow
.32; not significant .32; not significant 0.99; not
significant
Aspiration-
Postswallow
0.08; not significant No Test 0.028; significant
Aspiration-Any 0.08; not significant No Test 0.028; significant
Width of UES
Opening-Lateral
3ml liquid: 0.09; not significant
5ml liquid: 0.23; not significant
3ml paste: 0.015; significant
3ml liquid: 0.74; not significant
5ml liquid: 0.33; not significant
3ml paste: 0.023; significant
.60
.67
.22
Anterior Hyoid
Movement
3ml liquid: .91; not significant
5ml liquid: .45 not significant
3ml paste: .34 not significant
3ml liquid: .75; not significant
5ml liquid: .40; not significant
3ml paste: .20; not significant
.12
.67
.056
Superior Hyoid 3ml liquid: .81; not significant 3ml liquid: .99; not significant .88
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Movement 5ml liquid: .25; not significant
3ml paste: .59; not significant
5ml liquid: .12; not significant
3ml paste: .044; not significant
.98
.55
Anterior Larynx
Movement
3ml liquid: .64; not significant
5ml liquid: no test
3ml paste: .87; not significant
3ml liquid: 0.026; significant
5ml liquid: no test
3ml paste: .30; not significant
.40
No test
.12
Superior Larynx
Movement
3ml liquid: .73; not significant
5ml liquid: no test
3ml paste: .49; not significant
3ml liquid: .55; not significant
5ml liquid: no test
3ml paste: .009; significant
.65
No test
.84
Width of UES
Opening-Anterior
3ml liquid: .52; not significant
5ml liquid: no test
3ml paste: no test
3ml liquid: .32; not significant
5ml liquid: no test
3 ml paste: no test
.75
No test
No test
Confidence of Findings
While evaluating this article, a few limitations of this study were found. Firstly, the
frequency of exercises completed within each condition was not clearly described, creating a
problem with replication and therefore the ability to generalize the results found. Secondly, the
statistical analysis section of this article relied heavily on substantial knowledge of statistical
measurements. This entire section of the article was ambiguous and unclear. Additionally,
attrition of participants was significant, which impacted the confident level of the results found.
The limitations found weigh on my confidence level of this study’s findings.
In general, even given the limitations, I am fairly confident the results found truly
demonstrated the effects of the independent variables on the dependent variable due to the
study’s attempts to control extraneous variables and combat internal and external threats to
validity. Moreover, I am fairly confident this study fulfilled the requirements of a true
experimental research design and attempted to compare two swallowing therapies using valid
and reliable implementation and instrumentation. The questions remaining about the data
collection process could be easily found by contacting any member of the research team. This
study utilized many avoidance techniques to combat internal and external threats to validity. To
protect the validity and integrity of the study, a stratifying sample procedure was used in
conjunction with random assignment to ensure initial group equivalency, the clinicians were
trained and presumably highly competent in each intervention to ensure each participant received
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the same intervention, the two analysts were blinded and reviewed masked video recordings to
decrease the possible influence of biased observers, and the two conditions were explicitly
described which increased the likelihood of replication.
Conclusion
Guiding Practice
Practicing speech language pathologists could use this article to guide their practices in a
number of ways. Three out of five participants who finished the study in the Shaker group had
no post-swallow aspiration at post intervention testing when post-swallow aspiration was present
at pretesting. The number of participants was greatly smaller than researchers anticipated and
the p-value of these measurements were not shown to have statistical significance. However,
given that three out of five individuals no longer aspirated after swallowing in the post
intervention assessment, I would say the practical significance is evident. In contrast, no
improvements to post swallow aspiration were shown in the traditional therapy group.
Therefore, this article could guide clinicians towards further research of the Shaker exercise for
the remediation of post-swallow aspiration.
Likewise, the traditional therapy techniques demonstrated increases from pretesting to
post testing in regards to superior and anterior laryngeal movement and superior hyoid
movement. While the p-value for all three of these measurements do not specifically display
statistical significance for dysphagia (less than .02), they do make a compelling argument for the
effectiveness of traditional therapy as opposed to the Shaker exercise which showed no statistical
significance on these three measurements. Given a client with minimal elevation and forward
movement of the larynx, this article could point a clinician in the direction of finding and
evaluating more research on traditional therapy and its effectiveness.
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Evidence-Based Practice
According to author Timothy Meline (2010), evidence-based practice is a process
intended to provide clients with the best quality interventions through examining and comparing
three main components. These components include current, relevant scientific evidence, clinical
experience, and client preferences. It is essential to the process that each of these components is
taken into account before making clinical decisions or recommendations (Meline, 2010).
To examine the scientific evidence, a component of evidence-based practice, the table in
the Gillam and Gillam (2006) article that discusses critical appraisal questions related to
randomized clinical trials (level 1 evidence) can be used. The first two questions inquire about
random assignment and the presence of a control group. In this study, the participants were
randomly assigned to one of two conditions, a Shaker exercise treatment group and a traditional
therapy comparison group. The third question relates to the participants and the information
disclosed about all participants within the study. This study displayed the demographics of the
participants in a graph. All the participants demonstrated a history, of at least three months, of
aspiration. Many of the clients on caseload are on diet modifications due to overt or silent
aspiration. The sample used in this study were stratified based on the etiology of their aspiration;
once stratified, the participants were randomly assigned to ensure initial group equivalency. A
minor concern related to initial group equivalency was a discrepancy in the number of
participants in each group. At the study’s start, 11 patients were in the traditional group and 8 in
the Shaker group. After the loss of five participants, 9 ended in the traditional group and 5 in the
Shaker group. The next two questions relate to blinding procedures and reliable measurements
of the dependent variable. The analysts who reported the results were blinded and the videotapes
themselves were masked. Additionally, the observations of the clinicians implementing the
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independent variables were compared with the observations of the two blinded analysts,
providing interobserver reliability. The researchers providing explicit training to at least the
clinicians implementing the interventions and the pretest measurement procedure was identically
replicated for posttest data collection. The problem lies with the lack of statistical significance
shown and the absence of practical significance. The majority of p-values reported,
demonstrating a difference in pre and post test results, were not less than .02; most of the results
were not even less than .05, the general standard for communication disorders. The only p-
values that fit these criteria were for the width of the UES opening in both groups, and the
superior and anterior larynx movements and superior hyoid movement in the traditional therapy
group. The researchers did not provide practical significance through the reporting of the effect
size. Most of the answers to the critical appraisal questions regarding this study were yes.
According to Gillam and Gillam (2006), the more yes answers provided in this appraisal process,
the more assured clinicians can be that a study is reliable and high quality. That being said, the
lack of practical significance reported and the minimal statistical significance found doesn’t yield
great confidence in either of the two interventions.
The other two components of evidence-based practice are clinical experience and client
preference. Since August, numerous residents have shown positive results in their swallowing
from both intervention strategies. The quickest results seen at this facility for oropharyngeal
dysphagia have been when using the two interventions, traditional therapy and the Shaker
exercise, concurrently. Unfortunately, patients at this facility have to be sent out to receive
barium swallow studies, which occurs infrequently, leaving the measurements of signs and
symptoms of dysphagia to be measured by bedside assessments, meal analysis, and checklists
usually reported by observations alone. As for client preference at this facility, I have found that
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the only real preference is in relation to the diet modifications. The majority of clients at this
facility do not want their oral intake, especially coffee, altered in any way regardless of the
ramifications. The most frequent complaint received by the rehabilitation team is the aversion to
the exercises that are most straining such as the interdental swallow (Valsalva exercise).
After careful analysis and consideration, this study alone does not confidently
demonstrate support for the Shaker exercise being an evidence-based practice. While I am fairly
confident in the results found based on the research design and implementation, the results did
not prove the effectiveness in reducing aspiration of either intervention group. This is the first
randomized clinical trial comparing these two interventions. Given the amount of research on
the Shaker exercise and traditional maneuvers available to reference and the thoughtful design of
this study, supplementary randomized clinical trials could be completed to further investigate the
effectiveness of traditional therapy and the Shaker exercise on improving oropharyngeal
dysphagia. However, given the results seen in the rehabilitation facility, the goals of the clients
to return to a normal consistency diet, and the improvements (UES opening, hyoid movement,
larynx movement) found by this study (and the lack of regression/worsening), these two
swallowing interventions could be trialed in practice and monitored for efficacy.
Further Research Needed
Past research studies have shown the Shaker exercise to have resulted in an increased
UES opening. This clinical trial also demonstrated a statistical significance in the measurement
of the UES opening width from pretest to post-test; however, only five participants were given
post pre and post tests. Another randomized clinically trial should be completed, replicating this
study’s research design, with a greater number of participants to add another level of validity and
reliability to the results found. Additionally, further randomized clinical trials should be
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completed to evaluate the Shaker exercise’s effectiveness at reducing aspiration. This study’s
results were not statistically significant; however, three out of the five showed no post swallow
aspiration at the time of post test. Narrowing the dependent variable to be measured and
explicitly defining the implementation of the independent variable should be focused on in any
replication studies of this nature. Lastly, replicating this study utilizing a different sample of
participants from the dysphagia population would help generalize results to individuals who have
oropharyngeal dysphagia due to other etiologies besides cancer and stroke. Including individuals
who have dysphagia due to neurological conditions, laryngeal trauma, or medication interference
would be helpful in the generalization of results.
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References
Gillam, S. L., & Gillam, R. B. (2006). Making evidence-based decisions about child language
intervention in schools. Language, Speech, and Hearing Services in Schools, 37, 304-
315.
Meline, T. (2010). A research primer for communication sciences and disorders. (pp. 49-69).
Boston, MA: Pearson Education, Inc.