shewman - emg and cmd

8/11/2019 Shewman - EMG and CMD

1/16

Surface Electromyography (SEMG)

inCraniomandibular Dysfunction

Objective - Learn to:

1. Understand some of the implications ofthe muscular system in clinical decision making.

2. Objectively measure neuromuscular components toenhance clinical making decisions

Put EMG/Instrumentation in the Proper Context!

Copyright Todd ShewmanAll rights reserved

Readers Digest Version

Only so much time

Why was this Written?

www.noraxon.com

Clinically, the

determination of the

presence or absence of

TMD does not appear to be

enhanced by the use of

SEMG.

Klasser GD, Okesan JP.

J Am Dent Assoc. 2006

Jun;137(6):763-71.

MuShin Marking Territory

www.noraxon.com


2/16


3/16

Copyright Todd Shewman-All rights reserved

HEALTH CRITICALLY ILL

HomeostatisThe ability or tendency of anorganism or cell to maintain

internal equilibrium byadjusting its physiologic

processes.

Copyright Todd Shewman-Allrights reserved

WHY Does.Rate of Breakdown EXCEEDS the Rate of Repair?

WHY?

Whats your philosophy?

Copyright Todd ShewmanAll rights reserved

Goal of Clinicians

To increase the patientsability to adapt

NOT

rely on it!

Presentation Topics

Part I

History of SEMG in Craniomandibular Dysfunction(CMD)

Advantages and Limitations of SEMG in CMD

Part II

Basic SEMG Processing and Instrumentation Artifacts and Recording Error Sources

Troubleshooting

Normalization and its Importance

Then What?

Other technologies (Jaw Motion and Joint Sound)and how can they help us?

Overview

Craniomandibular dysfunction (CMD)

a group of disorders of the mast icatory muscles,

temporomandibular joint and associated areas. (Thilander)

Approx 60 - 70% of the general population has at least one

sign of CMD.

These include:

Pain in the preauricular region Temporomandibular Joint (TMJ),

masticatory muscles, cervical and shoulder muscles.

Limitation or deviations in mandibular ROM.

TMJ sounds during mandibular function.

Iva Alajbeg, Melita ValentiE-Peruzovi, Ivan Alajbeg, Davor Ille, Dubravka Knezovi-Zlatari, Marina Katunari


4/16

History of SEMG inCraniomandibular Dysfunction

CMD

TMD nomenclature has dominated the literature

SEMG used in classic biofeedback to promoterelaxation of orofacial muscles associated withC/TMD (Canniststraci, Gervitz)

These approaches presumed a cyclical relationshipbetween dysfunctional oral habits such as jawclenching or bruxism, aberrant biomechanicalloading of articular and periarticular structures,psychological stress, and pain. (Nicholson)

Copyright Todd Shewman-All rights reserved

Faulty Joint

and/or tooth

Position

Reflexive and

postural

responses

Muscular

Response

Faulty Joint Function

Tonic (long

term)

influences on

muscles, and

joints

Faulty Joint

Movement

Pain

Teeth Joints and Muscles?

Psychologic

Stress

History of SEMG in CMDContd

CMD patients engage in unconscious oralbehaviors that include chronic hyperactivityof masseter and temporalis muscles withlittle conscious awareness of their habit. (Flor,Glaros)

SEMG feedback techniques have been usedto assist patients with awareness andresolution of muscle hyperactivity. (Turk, Hijzen)

SEMG has been used in dental investigationsof normal and aberrant neuromuscularrelationships around the temporomandibularjoints for many years.

Historical Overview

Muscle disorders may precede TemporomandibularJoint (TMJ) problems and both disorders may coexistand often influence each other.

Schiffman EL, 1990.

Naeije M, 1986. Laskin D, 1969. Juniper R, 1984.

Current evidence demonstrates a strong relationshipbetween temporomandibular dysfunction TMD/CMD,muscle activity and dental occlusion (teethintercuspation).

Occlusal variables influence natural masticatory musclefunction and thus affect the temporomandibular joint.(Bjork et al)

Still no standard definition! Chasing a disorder?

To Share - Why Im Here

www.noraxon.com www.noraxon.com

Occlusal features can

affect the electrical

signals recordings of

masticatory muscles.Francesca Trovato, Bruno Orlando, Mario Bosco

Occlusal features and masticatory muscles activity. A

review of electromyographic studies Stomatologija,

Baltic Dental and Maxillofacial Journal, 2009, Vol.

11, No. 1


5/16

..is the study of muscle functionthrough the inquiry of the electrical

signal the muscles emanate.

Basmajian&DeLuca, Muscles Alive 1985, page 1

Electromyography...

What is it? Origin of the EMG Signal

From: Kumar/Mital 1996, p. 61, 64

Muscle FibersNervous system command produces a muscleaction potential on the muscle membranes

Muscle Contraction / Muscular Work

SEMG = A window

into components of

this physiologic

process

What Is Surface Electromyography SEMG?

SurfaceElectromyography

(SEMG) is the recordingof the algebraic sum of

voltages associated withmuscle action potentials

within their detectionzone from the skinsurface. (Basmajian)

SEMG Advantages

The subject is free to assume any position

Perform any functional movement that isdesired.

Recordings can be made from most any skinsurface. (e.g. extra/intraorally, pelvic floor)

Muscle activity is easily evaluated wheredynamometers would be impractical. (e.g.facial muscles).

Surface recordings are non-invasive andpainless.

Where Can Electrodes be Placed?

www.noraxon.com


6/16

SEMG Advantages (Contd)

Recordings are extremely sensitive to:

1. Muscle activity at rest2. Small changes in muscle activity

3. Low levels of muscle activity

4. To forceful contractions.

Within certain limits, the activity of particularmuscles or muscle groups can be distinguishedand quantified.

Set up is relatively quick and uncomplicated.

SEMG Limitations

Individual motor units cannot be reliablydiscriminated with SEMG

Electrical activity of deep muscles may not beisolated

SEMG can NOT diagnose neuropathologies

Is Surface ElectromyographyReliable/ Reproducible?

Amplitude:Castroflorio T, 2005, Bigland and Lippold, 1954; Goldensohn, 1966; Lloyd, 1971; Mitani and

Yamashita, 1972; Molin, 1972; Moss, 1974; Ahlgren, 1975; Milner-Brown and Stein, 1975;

Moller, 1975; Mitani and Yamashita, 1978; Hermens et al., 1986; Kydd et al., 1986; Burdette

and Gale, 1987; Christensen, 1 989; Neill, 1989; Van Eijden, et al., 1990; Dean et al., 1992

Frequency Analysis:

Barker GR, Wastell DG, Duxbury AJ. Spectral analysis of the masseter and anteriortemporalis: an assessment of reliability for use in the clinical situation. J Oral Rehabil.1989 May;16(3):309-13.

Thomas NR: The effect of TENS on the EMG mean power frequency. In: Bergamini M,

ed. Pathophysiology of Head and Neck M usculoskeletal Disorders. Front Oral Physiol

Basel: karger; 1990;162-170.

Buxbaum J, Mylinski N, Parente FR. Surface EMG reliability using spectral analysis. J

Oral Rehabil. 1996 Nov;23(11):771-5.

Test-Retest Reliability

Komi and Buskirk

- Inserted electrodes - .62

- Surface electrodes - .88

Statistical results confirmed that

Surface electrodes are more reliablethan intramuscular on day to day

investigations

Giroux B, Lamontagne M. Electromy Clin Neurophysiol 1990 Nov 30(7):397-405

What Do We Do Now?

Movements are observed

Relevant muscles are palpated

Limiting

Subjective Purely Qualitative May predispose the clinician to a false diagnosis if derived

from palpation alone. Paesani D, 1992.

Correlation between masseter muscle palpation and its

electromyographic activity was very low. Biasotto et al

Manual Muscle Testing is an alternativewith some degree of quantification (0-5)

Techniques are:

Unpopular for TMJ region.

Insensitive to small changes

in tension.

Insensitive to muscle activitynear resting levels.

Unable to monitor between

synergists and antagonists

Insensitive to muscle activity

patterns during dynamic

functional activities.


7/16

Limited to static /small window ofmoments in time. When teeth are

together, or close together.

Does not reveal informationregarding muscle activity. Or

muscle Dynamically.

Tends to be bulky and mayinfluence natural path of closure.

Intraoral/occlusal pressure distributiontechnology can be used to measure

resultant occlusal forces andcontact(s) with greater accuracy

Jaw Kinematics DevicesDocumentation of kinematic movement and velocity

Limited in terms of quantification of muscle activity at rest,during movement, and timing of specific muscle groups.

Joint Vibration/Sounds

www.noraxon.com

Imaging techniques

(e.g. X-rays) are used toevaluate:

Osseous and dentalstructures

Disease

Alignment of the jaw,skull, and neck area

Help to determineskeletal anomalies andasymmetries

Limited to static situations, fixed postures and do not

provide information regarding muscle activity.

SEMGUsed to assess the magnitude and timing of overall

muscle contraction.

Examines the ensemble of motor events that subserve

useful activity. E.G. Posture, clenching, swallow.

Functional muscle activity.

What does Surface

Electromyography (SEMG) Offer?

SEMG offers a window to the movementsystem that cannot be replicated by any other

means.

Glenn Kasman MS PT

Philosophical, Scientific and Clinical

View


8/16

SEMG and CMD

SEMG activity associated with occlusal and CMDdysfunction has been investigated, compared

to normal subjects and, expressed in terms of:

Baseline/Postural amplitude

Asymmetry

Timing

Mandibular elevator ratios (synergists)

Ferrario VF, Sforza C, MianiA Jr, DAddona A, Barbini E. J OralRehabil. 20:271-280;1993.

Visser A, McCarrollRS, OostingJ, Naeije M. J Oral Rehabil1994 Jan;21(1):67-76

Ferrario VF, Sforza C, Colombo A, Ciusa V. J Oral Rehabil. 2000 Jan;27(1):33-40.

Abekura H, KotaniH, Tokuyama H, Hamada T. J OralRehabil 1995 Sep;22(9):699-704

Naeije M, McCarroll RS, Weijs WA. J OralRehabil1989 Jan;16(1):63-70

Cline Bodr, Say Hack Ta, Marie Agnes Giroux-Met ges and Alain Woda. Pain Volume 116, Issues 1-2, July 2005, Pages 33-41.

When to Consider SEMG in the

CMD patient

Start With

Clinical Exam

www.noraxon.com

When to Consider SEMGin the CMD Patient

When to Consider SEMG in theCMD Patient

SEMG Evaluation is indicated

if:

Functional limitations and disability are clearlyidentified.

Neuromuscular impairments are a suspectedcomponent.

Serious medical or psychologic pathology isunlikely, or, is concurrently being addressed by acare provider.

Information regarding muscle activity is likely toassist with insight into the case and have an impacton treatment planning.

Common Recording Sites 4-8 Generally used:

Temporalis Anterior

Masseter

Suprahyoid

Sternocleidomastoid

Temporalis Posterior

Cervical Paraspinals (C4)

Upper Trapezius

What Muscles Should be Measured?


9/16

QUESTIONS, COMMENTS, DISCUSSION

SEMG Instrumentation

The Boring andNecessary

Information

Understand theresearch

To UnderstandClinical information

www.noraxon.com

ISEK Proceedings 2006

Quality of reporting EMG studies inevaluating masticatory muscles is poor!!

Appropriate report and use of EMGtechnique is necessary to provide more

accurate results and conclusions.

Quality of Reporting Masticatory MuscleElectromyography

Because of the general poor quality of reportingof the analyzed studies, findings of studies

using surface electromyography ofmasticatory muscles should be interpreted

with caution.OLIVO, 2007

Basic EMG Processing

EMG is a Random BIPOLAR Signal

www.noraxon.com

Differential

Amplifier

Display

Unit

Depolarisation wave

Electrodes

T1 T2 T3 T4 T5

+ - + - + - + - + -

Potential differencebetween electrodes

Differential

Amplifier

Display

Unit

Depolarisation wave

Electrodes

T1 T2 T3 T4 T5

+ - + - + - + - + -

Potential differencebetween electrodes

Basic EMG Processing

RAW EMG signal Alternating current .Needs to be made positive formeaningful calculation.

Rectification The RAW signalnegatives made positive.

RMS Root mean square -Reflectsmean power of the signal - mostcommon.

Moving Average - estimator of theamplitude behavior. Relates toinformation about the area under theselected signal epoch /window

Raw

Rectified

Smoothing

RMS -50ms

Moving Average

Smoothing - 50ms


10/16


11/16

Hardware Notch FilterEliminates designated frequencies successively

Filtered Out

~30%

Notch Filter

Filtered Out

~30%

Effect of notch Filter on Amplitude

Without and with Notch Filter

Hardware notch filters are not recommended(ISEK, SENIAM, Soderberg, Konrad, Raez, Robertson)

Was there a Notch Filter??

Read More than just the Outcome

What was the sampling Rate?

What was the bandpass filter?

Was there a Notch Filter

Was there amplification (by how much)?

Electrode placement preparation?

Electrode Type?

Inter Electrode distance?

www.noraxon.com

Knowing limitations is JUST as important

as outcome of data!

Troubleshooting Basics

www.noraxon.com

SEMG curves should be linked tovoluntary movement/recruitment.

Be suspicious of major amplitudedeviations not appear linked to

patient behavior.

Be alert for any rhythmicwaveform activity (e.g. respiration

or heart-rate artifact).

Common ArtifactsStable Baseline- Raw Data

www.noraxon.com


12/16

Common ArtifactsStable Baseline - RMS

www.noraxon.com

50/60 Hz Hum/Noise

Wall power/ground noise results in

increased baseline noise (50/60 Hznoise.

Often another device (old buildings)causes this problem.

Ground all devices.

Change the power plug.

Avoid multiple plug connectors andcable drums for the EMG amplifier.

Telemetry EMG device - Oftenbypasses this issue.

www.noraxon.com

Undesired Movement Artifact

Generally not as much of an issuewith CMD unless more extensive

evaluation.

1. blink of the eyes is oftenseen from the temporalis

anterior

2. Involuntary swallow from thesuprahyoidsite.

Not considered noise, this typeof artifact is generally reduced

through proper patient

instructions.

www.noraxon.com

Poor Electrode or Lead

Contact

Generally resolved bycleaning the electrodesite and replacing the

electrode

Ensuring a proper leadcontact to the electrodeand instrumentation.

Other possibilities

include patient cable orhardware damage.

www.noraxon.com

Electrode bridging

Poor lead contact

Heart Rate Artifact

Cervical paraspinal andtrapezius sites.

Biological artifact

Often cannot be avoided.

Reduced by:

Good skin preparation

Modified position of theground electrode.

State-of-the-art signalprocessing routines canclean these bursts withoutdestroying the regular EMGcharacteristics.

www.noraxon.com

Sternocleidomastoid With ECG Artifact

www.noraxon.com


13/16


14/16

Absolute microvolt values should not be comparedacross manufacturers!

Different:

Electrode characteristics

Sampling characteristics

Frequency bandpass filters

Microvolt amplitude quantification methods

Other processing characteristics

www.noraxon.com

Absolute amplitude values cannot be compared acrosssubjects and days!

Different: Adipose characteristics across subjects

Skin impedance characteristics

Unintended variations in electrode placement

Fascial thickness

Example:

10 uV from the same muscle between 2 people does not mean the samething!

10 uV from the temporalis anterior in one person probably does NOTmean the same thing as 10 uV from the temporalis anterior in another

person.

www.noraxon.com

What can we do about it?

Normalize!

www.noraxon.com

Normalization Procedure

First, a standardized isometric procedure (e.g. functional clench) i sidentified and performed for a defined period, (e.g. such as 2-3

seconds). Clench convenient and standard part of CMD protocol.

www.noraxon.com

Maximal Clench Values:

Right Temporalis Anterior

(RTA) 207uV

Left Temporalis Anterior (LTA)

164uV

Right Masseter (RMAS)

180uV

Left Masseter (LMAS) 217uV

SEMG activity is then averaged for a fixed period during the peak values (e.g. peak 500-1000ms of

a 2 second contraction). Thismean becomes the normalization reference value for the muscle.


The evaluation task of clinical interest is performed. The clinical task meanis divided by the MVIC meanand multiplied by 100 to complete the

calculation.

www.noraxon.com


First, a standardized isometric procedure (e.g. functionalclench) is identified and performed for a defined period,(e.g. such as 2-3 seconds). Clench convenient and

standard part of CMD protocol.

SEMG activity is then averaged for a fixed period duringthe peak values (e.g. peak 500-1000ms of a 2 second

contraction). This meanbecomes the normalizationreference value for the muscle.

The evaluation task of clinical interest is performed. The

clinical task mean is divided by the MVIC meanandmultiplied by 100 to complete the calculation.

www.noraxon.com


15/16

Normalized Comparisons for Symmetry

For symmetry documentation, activity of onemuscle is compared with that of itscontralateral partner. (E.G. Left/RightMasseter)

Muscle activity among homologous pairs isexpected to be simultaneously symmetric for

bilateral simultaneous symmetricalmovements (e.g. mandibular depression andelevation).

Reciprocally symmetric SEMG activitypatterns are expected for reciprocallysymmetric movements (e.g. left and thenright lateral excursions).

www.noraxon.com

R L


www.noraxon.com

Does R L ?


Percent difference in peak or average

activity produced during a movement.

Example:

Peak or avge activity = 40.7 uV on left

Peak or avge activity = 83.1uV on right

Right side -left side/right side x 100

High side Low Side/High side x 100

Example: Asymmetry during a functional clench.

83.1 - 40.7 83.1 x 100 = 51% Rt > Lt.

www.noraxon.com

High Side - Low Side High Side X 100 = Percent Asymmetry

83.1uV - 40.7 uV 83.1uV x 100 = 51% Asymmetry Rt. > Lt.

Asymmetry Index

Using standard asymmetry (15%) evidence held up for Rightside TMD patients. Left side did not (~10% asymmetry).

Combined ~170uV (Pain group Control Group ~279uV).What was resting activity?

Resting for pain group would have to be less than ~3uVacross all sites.

Non-Pain group ~ 6uV

Take Home Message Never rely on ONE piece of data!

www.noraxon.com

U. Santana-Mora Changes in EMG activity during clenchingin chronic pain patients

with unilateraltemporomandibular disorders. Journal of Electromyography and Kinesiology 19 (2009) e543e549

Qualitative Analysis

Is the muscle active?

Quickly answered with yes or no.

Ensure quality of the SEMG baseline allows a clearidentification of active SEMG.

Knowledge of the instrumentation must be known to the user.

Noise may be interpreted as increased activity. Post movement, a healthy subject tends to exhibit prompt

return to baseline levels.

If activity remains elevated, this can be qualitatively describedas a delay in returning to original baseline levels.

www.noraxon.com

Qualitative Analysis Baseline Values

Baseline values from non-postural muscles should be relati velyclose to the internal noise levels of the instrumentation.

Limits uV values to wi thin the same session (assumingelectrodes are not removed and replaced).

Relative microvolt (uV) values may be expressed as long asthey are not compared across sessions and subjects.

Timing parameters (when it turns on/off)

www.noraxon.com


16/16

shewman - emg and cmd

Documents