2. The original McComas technique (1971) The original McComas technique (1971) 10 S-MUAP are evoked at one single point of stimulation ALTERNATION The Multiple Point Stimulation method (Doherty & Brown, 1993) The Multiple Point Stimulation method (Doherty & Brown, 1993) 10 S-MUAP are evoked at 10 distinct stimulation points NO ALTERNATION, BUT NOT APPLICABLE TO ANY SUBJECT OR PATIENT

3. Incremental Stimulation (McComas 1971) - percutaneous nerve stimulation - short stimulation duration (50 µs) - weak intensity gradually increased by increments of 0.1 to 0.5 mA Individual and sequential activation of motor axons The Adapted Multiple Point Stimulation Method: AMPS (Kadrie et al. 1976; Wang & Delwaide 1995)

4. The mean motor unit size is estimated by the evocation of 10 S-MUAP by using incremental stimulation in distinct points of the median nerve between the wrist and elbow. The mean motor unit size is estimated by the evocation of 10 S-MUAP by using incremental stimulation in distinct points of the median nerve between the wrist and elbow. At each stimulation point, two or three S-MUAP are successively evoked and the compound motor response is selected only if S-MUAP are free of alternation. At each stimulation point, two or three S-MUAP are successively evoked and the compound motor response is selected only if S-MUAP are free of alternation.

5. AMPS:S-MUAP selection criteria With distinct thresholds With distinct thresholds In an all-or-nothing manner In an all-or-nothing manner Without any fractionation of the compound motor responses to successive suprathreshold stimuli Without any fractionation of the compound motor responses to successive suprathreshold stimuli In an orderly and reproducible manner In an orderly and reproducible manner S-MUAP have to be evoked

6. AMPS advantages AMPS minimises alternation AMPS minimises alternation Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS is non- invasive and painless AMPS is non- invasive and painless AMPS is a fast procedure AMPS is a fast procedure No specific collection system or software is required No specific collection system or software is required

7. AMPS minimises alternation AMPS minimises alternation Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS is non- invasive and painless AMPS is non- invasive and painless AMPS is a fast procedure AMPS is a fast procedure No specific collection system or software is required No specific collection system or software is required AMPS advantages

8. AMPS minimises alternation AMPS minimises alternation Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS is non- invasive and painless AMPS is non- invasive and painless AMPS is a fast procedure AMPS is a fast procedure No specific collection system or software is required No specific collection system or software is required AMPS advantages

9. TEST 1 TEST 2 40100200 40 100 200 r = 0.83 CV = 9.5% µV.ms µV.ms 100 400 r = 0.95 CV = 10.4% MU 70 70 100 400 MU A. Thenar MUNEB. Average S-MUAP size

10. AMPS advantages 1000 1000 r = 0.83 P < 0.001 F-response method AMPS 50100 50 100 MU MU

11. AMPS minimises alternation AMPS minimises alternation Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS is non- invasive and painless AMPS is non- invasive and painless AMPS is a fast procedure AMPS is a fast procedure No specific collection system or software is required No specific collection system or software is required AMPS advantages

12. AMPS minimises alternation AMPS minimises alternation Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS is non- invasive and painless AMPS is non- invasive and painless AMPS is a fast procedure AMPS is a fast procedure No specific collection system or software is required No specific collection system or software is required AMPS advantages

13. AMPS minimises alternation AMPS minimises alternation Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? Incremental stimulation avoids any significant motor unit selection bias ? Erlanger and Gasser ? AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS results are reproducible (CV = 10%) and fit well with those obtained, in the same population, using an other estimation method: the F- response technique. AMPS is non- invasive and painless AMPS is non- invasive and painless AMPS is a fast procedure AMPS is a fast procedure No specific collection system or software is required No specific collection system or software is required AMPS advantages

14. AMPS disadvantages AMPS is not a hands - off technique AMPS is not a hands - off technique The same S-MUAP recorded twice from two different stimulation points The same S-MUAP recorded twice from two different stimulation points A subjective bias in recognition of new S-MUAP is possible A subjective bias in recognition of new S-MUAP is possible AMPS is not applicable to study proximal or deep muscles AMPS is not applicable to study proximal or deep muscles

15. AMPS disadvantages AMPS is not a hands - off technique AMPS is not a hands - off technique The same S-MUAP recorded twice from two different stimulation points The same S-MUAP recorded twice from two different stimulation points A subjective bias in recognition of new S-MUAP is possible A subjective bias in recognition of new S-MUAP is possible AMPS is not applicable to study proximal or deep muscles AMPS is not applicable to study proximal or deep muscles

16. AMPS disadvantages AMPS is not a hands - off technique AMPS is not a hands - off technique The same S-MUAP recorded twice from two different stimulation points The same S-MUAP recorded twice from two different stimulation points A subjective bias in recognition of new S-MUAP is possible A subjective bias in recognition of new S-MUAP is possible AMPS is not applicable to study proximal or deep muscles AMPS is not applicable to study proximal or deep muscles

17. AMPS disadvantages AMPS is not a hands - off technique AMPS is not a hands - off technique The same S-MUAP recorded twice from two different stimulation points The same S-MUAP recorded twice from two different stimulation points A subjective bias in recognition of new S-MUAP is possible A subjective bias in recognition of new S-MUAP is possible AMPS is not applicable to study proximal or deep muscles AMPS is not applicable to study proximal or deep muscles

18. Techniques using the incremental stimulation Techniques using the incremental stimulation Multiple Point Stimulation McComas initial technique AMPS MOTORUNITNUMBER