emg muscle physiol2 test

7/27/2019 EMG Muscle Physiol2 TesT

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EMG, Muscle Physiology and

Behaviour 2

Author: Jennifer Wyndham

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Images: Pearson Education

Lippincott, Williams and WilkinsLawrence Erlbaum Assoc

[email protected]

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Objectives

After this session you should be able to:

Discuss the merits of needling vs surface recordingtechniques

Discuss current research in EMG studies on selectedareas of pathophysiology:

Muscle disorders/diseaseBehaviour and emotionSpeech and stuttering


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EMG in Clinical studies, 2009-2010

Eli P et al, 2009, Chemodenervation and Nerve Blocks in the Diagnosis and Managementof Spasticity and Muscle Overactivity, PM&R, Sept, 1, 9, 842-851

Furtner M, et al., 2009, Cerebral Vasoreactivity Decreases Overnight in Study of SevereObstructive Sleep Apnoea Syndrome, Sleep Medicine, Sept,10, 8, 875-881

Kumar S, and Prasad N, 2010, Torso Muscle EMG Profile Differences Between Patients

of Back Pain and Control,Clinical Biomechanics , 25, 103-109 Meyr A et al., 2009, Epidemiological Aspects of the Surgical Correction of Structural

Forefoot Pathology, J Ankle and Foot Surgery, Sept, 48, 5, 543-551

Pomerance J, 2009, The Cost-effectiveness of Non-surgical Vs Surgical Treatment ofCarpal Tunnel Syndrome, J Hand Surgery, Sept, 34, 7, 1193-1200

Staugaard S, 2010, Threatening Faces and Social Anxiety: A literature review , ClinicalPsychology Review30, 669-690

Turker KS. 2010, Reflexes As Tools to Study Human Neuromuscular System. ClinNeurophysiol:10.1016/ j.clinph., 201, .04.019.

Waite DL, Brookman RL, Dickerson CR, 2010, On the Suitability of Using SurfaceElectrode Placements to Estimate Muscle Activity of the Rotator Cuff As Recorded byIntramuscular Electrodes, J Electromyography &Kinesiology, Sept, 20, 903-911

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EMG in Clinical studies, 2008- 2009

Chan JKK,et al.,2009, Posterior interosseous nerve palsy in rheumatoidarthritis: casereport and literature review, J of Plastic, Reconstruct & Aesthetic Surgery,62, e556 -e560

Niels OB, et al., 2009, Clinical Outcomes of Surgical Release Among Diabetic PatientsWith Carpal Tunnel Syndrome: Prospective Follow-up With Matched Controls, J HandSurgery,Sept, 34, 7, 1177-1187

Jankovic J, 2009, Treatment of Hyperkinetic Movement Disorders, The Lancet Neurology,Sept, 8, 9, 844-856

Qu, X and Nussbaum MA, 2009, Evaluation of Passive and Active Control of Balance, JBiomechanics, August, 42, 12 1850-1855

Finsterer J, 2009, Mitochondrial Disorders, Cognitive Impairment and Dementia, JNeurological Sciences, August, 283, 1 &2, 143-148

Bartolo DC and Paterson HM, 2009, Anal incontinence, Best Practice &Research ClinGastroentorolgy, August, 23, 4, 505-515

Baranowski AP, 2009, Chronic Pelvic Pain, Best Practice &Research ClinGastroentorolgy, August, 23, 4, 593-610

Alizadehkhaiyat O, et al., 2009, Assessment of Functional Recovery in Tennis Elbow, JElectromyography and Kinesiology, August, 19, 4, 631-638

Ratnovsky A et al., 2008, Mechanics of Respiratory Muscles, Respiratory Physiology &Neurobiology, April, 163, 82-89


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How is the EMG signal used in research?

EMG and Behaviour

Biofeedback studies Frontalis EMG feedback for tensionheadache.

Facial and neck EMG used in stuttering.Placebo and group situations need to be taken into account.

NB Studies can be affected by social and environmental /

situational factorsSubjects may second guess the purpose of the experiment.

Thus use dummy electrodes; recording in both social and on-social contexts etc to minimise the problem

Motor Performance and Reaction Time (RT)

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Davis (1940) recorded EMG from forearm extensor muscles whilesubjects waited for a signal requiring a response. Muscle tension

began 200-400 msec after the signal. RT was faster the higher the

initial muscle tension was.

RT was quicker and muscle tension higher for regular foreperiods vs irregular periods.

Kennedy and Travis (1948) looking at tracking from the frontalismuscle showed that RT became slower with low levels of tension

and faster when tension level was high.

Non involved muscles show low EMG activity. This has been linkedwith decreases in HR (Cardiac-somatic concept).


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EMG and Tracking

Tracking - movement of a control to indicate a moving target. i.e.

Video games and pilots.

Efficient tracking is related to moderate to high EMG level. Lowmuscular tension (indication of drowsiness) or very high (over

exertion or fatigue) are associated with less efficient performance.

Practice improves tracking. Simple repetition without fatigueimproves performance.

Motivation facilitates performance. Fatigue hinders it (Eason andWhite). Fatigue causes integrated EMG levels to increase but

muscle efficiency to decrease.

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EMG and Speech

Oral EMGs occur during thinking (not confined to the larynx). Speech

muscles are separate. (Goldstein (1972) review of the literature).

muscle activity accompanies all cognitive phenomena, even though EMG

may be of small magnitude McGuigan (1973) .

Sub vocalisation during reading limits reading rate to 150 words/m.Hardyck et al., (1966) found 17/50 subjects were sub vocalisers.

Audio EMG feedback of the laryngeal muscles * - within 30 min. all were

able to read with EMG at resting levels.

Reductions in reading fatigue occurred.

McGuigan (1973) in a contrasting view suggested that higher levels of oralEMG in children and less proficient adults enhances comprehension levels,

and reduces distractions in a noisy environment.


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Marieb, Pearson education

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Involved in speech

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EMG and Emotion

Facial EMG

Schwartz and colleagues (1970s) found

different muscles are responsible fordifferent facial expressions

Muscles

corrugators: knit the browstriangularis: depress the mouthzygomatic: responsible for smilesUsing pleasant or unpleasant imagining.Fridlund and Cacioppo (1986)

presented guidelines for electrodeplacements in facial EMG research.

RHS of brain is active in spontaneousemotional response ie LHS muscles

showed increased activity.

This is contralateral control - RHS motorcortex is more active Andreassi, 2007


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EMG and Emotion (cont)

Individuals exposed to happy and angry pictures of facial expressionsshowed different responses. Happy picture increased zygomatic activity and

angry faces elicited elevated corrugator activity (Dimber (1982).

Further, measures of mood and EMG showed that feelings of elation anddepression were elicited in 70% of subjects. Elation increased zygomatic

activity and depression increased corrugator (Sirota and Schwartz,1982).

It has been hypothesised that the facial muscles play a role as a feedback

system for the experience of emotion. Original proposal by Darwin that facial

expressions are biologically pre-wired and consistent between individuals.

Gender difference. Women show more pronounced EMG response in the

zygomatic and corrugator muscles. Females are more facially expressive

than males (Dimberg 1997).

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Anger In and Out

Is there a difference in those who outwardly express anger vs. those

who internalise?

Jancke (1996) measured frontalis, corrugator, orbicularis oculi

(below the eye) and zygomatic EMG.

All subjects were asked to complete an IQ test.

Control group was given neutral feedback thanking them forentering the study.

Experimental group were told their score was too low and nopayment would be given.

Subjects who expressed anger outwardly had higher frontalis andcorrugator activity.

EMG displays serve a social communication purpose rather thanreflecting felt emotions.


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EMG during Mental Activity

Operant Conditioning of EMG

Hayes (1975) used EMG auditory feedback of muscle tension Grp 1.

Vs Controls:

Active or passive relaxation, Grp 2. No assistance group (told to be relaxed as possible) Grp 3. Non contingent feedback in the form of a random tone Grp 4.

The EMG biofeedback group achieved greater degrees of muscle relaxation

than either of the relaxation groups and much greater than either of thecontrols.

However, lowering EMG level in one muscle (eg frontalis) does not generaliseto other muscles.

But, can show classical conditioning (recording EMG from the masseter andforearm muscles) in exp. Grp, with conditioned stimulus (CS) an audio tone,

and an unconditioned stimulus (UCS) a different tone vs control Grp whichonly gets CS. Exp grp shows larger EMG to the CS than the control grp

indicating conditioning of the muscle being recorded

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EMG and Sleep

A review of the EMG literature during sleep and dreaming, Goldstein (1972), indicated that the

onset of dreaming is marked by a reduction in neck and head EMG activity.

EMGs decrease towards their lowest level 5 min before the onset of REM

sleep. The lowest level of EMG was during REM sleep.

Chin EMG is superior to lip EMG for identifying REM sleep.

EMGs of apnoea victims show that they have a decrease or completedisappearance of activity in the muscles of the throat and upper airways

compared to normal controls. This leads to obstructed airways

Different rhythms in daily muscle tone in short sleepers (SSP) vs Longsleepers (LSP) ie different waking levels in muscle tone on EMG during a

computer task

SSP showed greater EMG activity in the morning , but not eveningcompared with LSP - appears that long sleepers peak later in the day than

short sleepers!


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EMG Gradients

EMG has been shown to increase progressively from the beginning tothe end of a task for both mental and physical activities (tracking). The

increase is termed EMG gradients

The slope of the gradient is related to level of motivation, the steeperthe slope, the higher the motivation.

Bartoshuk (1955) reported that for mirror tracing the gradient slopewas related to speed and accuracy.

Incentive level raised EMG gradient. Svebak and Murgatroyd (1985) found that serious-minded subjects

had steeper gradients than playful persons (video car-racing

simulation).

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EMG and Respiratory Muscles

EMG can detect abnormal muscle electrical activity in diseases / conditions,e.g. musculardystrophy, muscle inflammation, peripheral nerve damage,myasthenia gravis etc

Incidence of respiratory muscle disorders (due to obesity orlung disease)e.g. COPD, asthma, chronic bronchitis is .

Dysfunction of respiratorymuscles may lead to respiratory failure wheremuscles cannot sustain work of normal quiet breathing.

High airway resistance, lung hyperinflation, in COPD, forcerespiratory.muscles to increase their work in breathing.

Breathing at abnormally high lung volume causes the inspiratory muscles tooperate at non-optimal lengths, reducing their maximal contractile forces.

Thus, the muscles are required to generate higherforces with each breath -small changes in breathingpattern or demand in exercisewould inducefatigue of the respiratory muscles

Ref: Ratnovsky A, et al., 2008


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EMG and Respiratory Muscles (cont)

EMG cangive information on level ofmuscle performance / activity withdifferent respiratory tasks andat different lung volumes thus enablesdifferentiation between different respiratory muscles.

Measurements of EMG signals from thediaphragm during inspirationrevealed peak values approx 50V during quiet breathing, and maximalvalues approx 150V as inspiration effort increases

EMG also useful for assessing respiratory muscle endurance and fatigueafter muscle trainingor exercise. Respiratory muscle fatigue isrelated tochange in the power spectrum i.e. EMG measured

Another indicator for muscle fatigue is areduction in ratio between theEMG powers in high frequency band to that in the low frequency band (H/Lratio)

Inspiratory loads higher than 50% of maximal diaphragmatic pressure leadto diaphragmatic fatigue"

Ref: Ratnovsky A, et al., 2008"

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EMG and Muscle Disorders

Repetitive Strain Injury

Repetitive movement has been known to be associated with thedevelopment of repetitive motion disorders (RMDs), a chronic overusecondition affecting muscles, nerves, joint leading to inflammation and /or

pain (Fuller et al., 2008)

Repetitive arm movements constitute a major facet of several workplacetasks (e.g. manufacturing, assembly line work, services) as well as many

sporting and leisure activities

During sustained maximal contraction, fatigue (reduced functionalcapacity) is observed as a decline in force output

The effects of fatigue on a muscles output show as compression of thepower spectrum towards lower frequencies in an EMG due to reduced

motoneuronal excitation


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EMG and Muscle Disorders

Repetitive Strain Injury (cont)

Other studies have shown increases in measures of the EMG amplitude(e.g. root-mean-square (RMS) value) concomitant to decreases in thefrequency characteristics with fatigue development during submaximal

contractions.

Studies of the mechanisms of low-force muscle fatigue, indicateselective fatigue of low-threshold motor units during sustained wrist

extensions and changes in physiological parameters (interleukin-6,

muscle lactate, K+, local tissue oxygenation, total haemoglobin) at theneuromuscular junction of the trapezius muscle during low-load

repetitive arm tasks.

In addition, gender differences in various aspects of the fatigueresponse mechanisms (e.g. endurance time, strategies of muscleadaptation) have been documented recently

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EMG and NeuroMuscular Disorders

Myasthenia Gravis

Autoimmune disease caused by anantibody- mediated loss of acetylcholinereceptors at the neuromuscular junctionand thus loss of communicationbetween motor neuron and muscle.

Peak incidence between age 20-30 yrs,3X more common in women. In later lifemore men affected then women

Weakness and fatigue with sustainedmuscle effort. Eye and periorbitalmuscle most commonly affected - ptosis(drooping upper eyelid) and diplopia(double vision).

Also weakness in muscles for chewing,swallowing, and limb movements - morepronounced in proximal than distal partsThus difficult climbing stairs and liftingobjects.

Ptosis in R eyelid


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Myasthenia Gravis (cont)

Lower facial muscles and thus speech impaired later in thedisease. Myasthenia crisis (due to stress, illness pregnancy, post

surgery) when weakness severe enough to compromise

ventilation- need artificial ventilation

Muscle weakness can be detected by single fibre-electromyography (EMG)

This detects delayed or failed neuromuscular transmission inmuscle fibres supplied by a single nerve fibre.

This can be confirmed by an immunoassay test to detect thepresence of acetylcholine receptor antibodies in the blood

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Parkinsons Diseases

Parkinsons Disease is a degenerativedisorder of basal ganglia function

Specifically degeneration of the dopamineproducing fibres in the substantia nigra

Results in variable combinations of tremor,rigidity and bradykinesia (hypokinesis)

Bradykinesia characterised by slowness ininitiating and performing movement, difficultyin sudden unexpected stopping of voluntarymovements

Patients lean forward to maintain their centreof gravity

Use surface EMG signals to discriminateParkinson tremor from essential tremor

ET is a relatively benign diseasewith thetremor being the main symptom

Also used for diagnosis when hypokinesisfirst appears


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Parkinson's Recent research indicates a genetic

component in early onset form ofParkinson's

Theory that auto-oxidation ofcatecholamines, such as dopamine, duringmelanin synthesis injures neurons in thesubstantia nigra.

Increasing evidence that diseasedevelopment may be due to accumulationof these toxic metabolites that the neuronscannot render harmless

Latter due to disruption of the mitochondrialelectron transport system which usuallyinactivate these metabolites

Those with family history have mutations inthe Park1 and sometimesPark2gene.Latter is rare

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Low Back Pain and Pelvic Floor Muscle tone

Low back pain (LBP) is one of the most common conditionsaffecting allpopulation, worldwide

Ranked first as a cause ofdisability and inability to work in the USA - highprevalence rate results in high associatedeconomic and social costs

The overall mechanical stabilityof the spinal column, especially in dynamicconditions andunder heavy loads, is provided by the spinal column and theprecisely coordinated surrounding muscles

Australian longitudinal study on women found those with pre-existingincontinence, gastrointestinal problems and breathing disorders were morelikely todevelop LBP than women without such problems.

This wasa result of changes in control of the trunkmuscles followinginvolvement with incontinence, respiratory and gastrointestinal problems.

Changes in morphologyand altered postural activity of the trunk musclesincludingmuscles of respiration and continence (providemechanical supportto the spine and pelvis) shownto be related to the development andoccurrence of LBP


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EMG and NeuroMuscular DisordersLow Back Pain and Pelvic Floor Muscle tone

EMG of co-activationpattern of the pelvic floor and abdominal muscles (needle EMG forthe abdominals &surface EMG for pelvic floor muscles (PFM)), found

- that theabdominals contract in response to a pelvic floor contractioncommand

- that the pelvic floor contracts in response toboth a hollowing and bracing abdominalcommand.

Thus pelvic floor can befacilitated by co-activating the abdominals and vice versa. Also,increasing abdominal muscle EMG activity resulted inincreasing EMG activity in PFM

PFMexercises were beneficial in improving PFM strength andendurance. PFM exerciseplus physiotherapy have a similar effect, BUT is not superior to routine physiotherapy forpatients with chronic LBP (Mohseni-Bandpei MA, 2010).

However, other studies indicate that improvement in abdominal strength and tone andresulting good posture does aid in reducing back pain.

Further, 78% of women with LBP reportedurinary incontinence i.e. LBPis a risk factorfor urinary incontinence

Various studies indicate that exercise of the abdominal muscles as well as the PFM to bebeneficial in maintaining PFM coordination, support,endurance, and strength and as wellas aiding in control of incontinence.

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Rheumatoid Arthritis

Chronic inflammatory disorderthat primarilyaffects the synovial joints.

Symptoms include the loss ofextension of thedigits, or dropped finger, this may be caused

by loss normal muscle function associated with

subluxation of the ulna,and of extensortendons over hand joints, and dislocation of the

metacarpophalangeal joints (MCPJs),

Posterior interosseous nerve (PIN) palsy, witha loss of digital extension, is a rare neurologicalcomplication of rheumatoid arthritis (RA). It

may be caused bynerve entrapment, vasculitisor drug toxicity.

The diagnosis of PIN palsy may be confirmedby electrophysiological studies which include

EMG.

The EMG results help determine treatmentoptions- medical/drug therapy or surgery"


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EMG and Behaviour and Emotion

The threatening facial expression isconsidered an ancient sign ofthreat inhuman evolutionary history

A mental disorder that seems especiallyrelevant in relation to threatening facesissocial phobia.

Socially anxious individuals are particularlyconcernedwith humiliating or embarrassingthemselves when under the scrutinyofothers

A threateningfacial expression can be asign of disapproval and rejection, and mighttherefore function as an anxiety-provokingcue in people for whomapproval isespecially important

People with social phobia formnegativeassumptions about how other people seethem, and theseassumptions cause aparticular attentiveness to threateningenvironmental cues

Facial EMG measures the valencedimension or strength of emotions"

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EMG and Behaviour and Emotion

Hypothesis that abiological predisposition to react to emotional faces willmanifestitself in a type offacial mimicry that can be measured with EMG.

Morespecifically, the large facial muscles, Zygomaticus major (controlssmiling), and Corrugator supercilii (controls frowning), should show

increased activation in response to happy and angry faces respectively.

Some studies have found increased Corrugator activity(frowning) to angryfaces in high, compared to low, socially anxiousparticipants whereas others

found no group differences in response to angry faces

Importantly, the studies which found aneffect specific to the angry faces,used long (100 ms) exposure durations, whileotherspresented their stimuliuntil participant response. This difference inexposure duration appears to becrucial.

Higher levels ofsocial anxiety within their clinical population correlated withmorepronounced avoidance of angry faces, compared to patients withlowerlevels of social anxiety.


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EMG and Stuttering

The neurophysiological processing of speech fluencydepends on the stabilityof temporal coordinationbetween motor execution and the performed cognitiveprocessing."

Developmental stuttering is a communicationdisorderthat begins in earlychildhood, (between 3 - 6 years)characterized byinvoluntary disruptions in thefluency of verbalexpression."

Hypothesized that stuttering may be due to a number of factors:

- atemporal disruption of the simultaneous and successive programming ofmuscular movements;

- anerror in sequencing the normal motor commandsthat leads to a delay inproduction of the sound;

- ananticipatory, apprehensive, hypertonic avoidancereaction an extraneousmuscle activity];"- the result of a deficiency in speech motor skill suchas a disorder in thecoordination of different musclesystems (respiratory, articulatory or laryngeal)or slower retrieval of speech motor plans."

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EMG and Stuttering

The most typical core behaviors arerepetitions of sounds or syllables andarticulatoryfixation, resulting in blocks or prolongations ofsounds.

Stutterers showed significantly higherEMG levels in the lower orbicularis orismuscle at thetime of speech onset and during speech productionthan non-stutterers.

However, studies focusing on EMG of the lipmuscles are controversial, andother studies have providedevidence that stuttering is not associated withunusually high levels of muscle activity in lip muscles."

The study by de Felicio et al.,(2007) was performed on the upperand lowerlip muscles in order to compare individuals who stutter and fluent speakerswith respectto electromyographic activity in speech and non-speech tasks."

Note: Stuttering is recognizedto have a genetic component (supported bytwin and adoption studies) - approximately half ofall stutterers have a familyhistory of the disorder,However, the exact mode oftransmissionare notknown"


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EMG and Stuttering

EMG study on stuttering noted:

1. the activity of the upperlip muscle was significantly lower in the stutterersgroup than in the control group in some clinicalconditions analyzed;

2. therewas no differencein the lower lip activity between stutterersandcontrols and

3. the results do not confirmthat subjects who stutter present higher levelsofmuscle activity in lip muscles than fluentspeakers.

Findings, including the rest activity, do notconfirm the view of stuttering as ahypertonic avoidance reactionor as an extraneous muscle activity

Also no evidence that stutterers, during fluent speech, presentan increasein the activity of the lower lip musclecompared to non-stutterers[14]."

In fact, the abnormal aspect of the EMG that hasbeen observed in subjectswho stutter is tremor inorofacial and laryngealmusclesduring disfluencies

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References:

Burke D, 2010, Whither Needle EMG, Clinical Neurophysiology, Editorial, 121 (2010)1373-1375

de FelicioCM, Rodrigues RL, Freitas G, Vitti M, Hallak Regalo SC, 2007, InternationalJournal of Pediatric Otorhinolaryngology(2007)71, 1187 - 1192

Fuglsang-Frederiksen A, 2006, The role of different EMG methods in evaluatingmyopathy,Clin Neurophysiol, 117, 1173-89.

Hossen A, Muthuraman M, Raethjen J, Deuschlc G, Heuteb U, 2010, Discrimination ofParkinsonian Tremor From Essential Tremor by Implementationof a Wavelet-based Soft-decision Technique on EMG and Accelerometer Signals, Biomedical Signal

Processing and Control, 5, 181-

188 DiscriminationofParkinsoniantremorfromessentialtremorbyimplementationofawavelet-

basedsoft-decisiontechniqueonEMGandaccelerometersignals" Mohseni-Bandpei MA, Rahmani, N, Behtash H, Karimloo M, 2010, The Effect of Pelvic -

floor Muscle Exercise on WomenWith Chronic Non-specific Low Back Pain, Journal ofBodywork & Movement Therapies, In Press

Ratnovsky A, Elad D, Halpern P, 2008, Mechanics of Respiratory Muscles, RespiratoryPhysiology & Neurobiology163, 82-89


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References:

Texts: Andreassi, JL, 2007, Psychophysiology 5th edition, (Ch 10 and 3),

Lawrence Erlbaum Assoc, Mahwah, New Jersey

Bear MF, Connors BW and Paradiso MA, 2007, Neuroscience 3rd edition,Lippincott, Williams & Wilkins, Wolter Kluwers, Philadelphia, (Ch 13)

Marieb E, Human Anatomy and Physiology, current edition Porth CM, Pathophysiology: Concepts of Altered Halth States, Lippincott,

Williams & Wilkins, Wolter Kluwers, Philadelphia, current edition

emg muscle physiol2 test

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