1

EMGanalysis of MUP

and IPStålberg

STÅLBERG

2 normal motor units2 normal motor units2 normal motor units2 normal motor units

STÅLBERG

MyopathyMyopathy

2

STÅLBERG

Reinnervated motor unitReinnervated motor unit

A

B

C

D

E

MU

ElectrodesElectrodes

Stålberg

ConcEMG

3

New MU over the cannula

A

B

7

4

oppositeside of nmj

end of propat tendon

slowly propSFAPrepolaristion

T

T

T

T

duration

startat nmj

phase

Stålberg

Parameters used in MUP analysisParameters used in MUP analysis

parameterparameter significancesignificance measurementmeasurement

• amplitude # fibres/0.5mm peak-peak• area # fibres/2 mm within dur• duration # fibres in 2.5 mm slope criteria• phases temp dispersion 0-cross + 1• turns “ change in dir• rise time closeness to fibre neg-pos peak• satellites extreme delay late spike• jiggle n-m transm shape stability

Stålberg,Nandedkar

This example: Multi MUP analysis

techniques to decompose a mixed signal into its constituentstechniques to decompose a mixed signal into its constituents

Decomposition;Decomposition;

Stålberg

5

Multi-MUP, result

500 uV

10 ms

NormalNormal

NeuropathyNeuropathy

MyopathyMyopathy

MultiMulti--MUP analysis in different MUP analysis in different disordersdisorders

Stålberg

ongoingreinnervation

normal

late stage

A

B

Dynamics of reinnervation

6

normal

Jiggle, ALS

Parameters to quantifyParameters to quantify

• shape of individual MUPs

• jiggle

• fullness

• recruitment (early, reduced)

• dynamic changes with time (fatigue)

Stålberg

Reference values - log amp

MUSCLENR: 26 Deltoideus

AGE

8070605040302010

log

ampl

(uV

)

4

3

2

1

sex

female

male

Total Population

Rsq = 0,0691

MUSCLENR: 26 Deltoideus

AGE

8070605040302010

log

ampl

(uV

)

4

3

2

1

sex

female

male

Total Population

Rsq = 0,0691

Stålberg

7

Summary of ref values Summary of ref values -- log amplog amp

514352424152613411228545675N =

Frontalis

Vastus lateralis

Tibialis anterior

Ext dig brevis

Gastroc med

Abductor pollicis

Flex c rad

Biceps brachii

Deltoideus

Trapezius

Triceps

Ext dig comm

Interosseus dorsalis

Mea

n +

- 2

SD

log

ampl

(uV

)

4,0

3,5

3,0

2,5

2,0514352424152613411228545675N =

Frontalis

Vastus lateralis

Tibialis anterior

Ext dig brevis

Gastroc med

Abductor pollicis

Flex c rad

Biceps brachii

Deltoideus

Trapezius

Triceps

Ext dig comm

Interosseus dorsalis

Mea

n +

- 2

SD

log

ampl

(uV

)

4,0

3,5

3,0

2,5

2,0

Muscles

Stålberg

InterferenceInterferencepatternpattern

8

EMG EMG -- interference patterninterference pattern

Normal

Myopathy

Neuropathy

1 s

1 mV

9

Interference pattern analysisin normal, neuropathic and myopathic conditions

10

envelopenss

SLIGHT MYOPTAHY

11

MODERATE NEUROGENIC

envelopenss

envelopenss

CENTRAL WEAKNESS

SLIGHT MYOPATHY (TYPE 2 ?)

envelopenss

12

MyopathyMyopathy

• spont (m) fib/psw myotonic CRD• spont (n)• MUP ↓ ampl ↓ dur• shape poly• jiggle• recruitment early• TA/FFT myopathic• fullness normal• FD ↑• jitter normal

Stålberg

Inactive neurogenicInactive neurogenic

• spont (m) • spont (n)• MUP ↑ ampl ↑ dur• shape• jiggle• recruitment late• TA/FFT neurog.• fullness ↓• FD ↑• jitter

Stålberg

Subacute neurogenicSubacute neurogenic

• spont (m) fib/psw CRD• spont (n) neuromyot myokymia• MUP ↑ ampl ↑ dur• shape poly• jiggle ↑• recruitment late• TA/FFT neurog.• fullness ↓• FD ↑• jitter ↑

Stålberg

13

Myasthenic patternMyasthenic pattern

• spont (m) (fib/psw)• spont (n)• MUP• shape• jiggle ↑• recruitment• TA/FFT• fullness• FD normal• jitter ↑

Stålberg

Central weaknessCentral weakness

• spont (m) • spont (n)• MUP normal• shape normal• jiggle normal• recruitment irregular• TA/FFT• fullness ↓• FD normal• jitter

Stålberg

Comparison of electrophysiological parameters

Parameters normal myopathy den/reinn axon loss CB central

SFEMG FD n n n n

Conv MUP n n n n

Conv IP n myo neur

Macro n n n n n

MUNE n n n n n

TMS n n n abn

Stålberg

14

Reasons for performing QEMG

• standardized way of measuring

• improved sensitivity

• new parameters

• results can be transferred– from one time to the other - follow up

– from one physician to the other

– from on lab to the other

• reliable results also from less experienced EMGers

• good for training Stålberg