Pr

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Adapted Multiple Point Stimulation Method AMPS
FC Wang, O Bouquiaux, V de Pasqua A Maertens de
Noordhout, PJ Delwaide
University Department of Neurology, Liège, Belgium
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• 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)
• 10 S-MUAP are evoked at 10 distinct stimulation
  points
• NO ALTERNATION, BUT NOT APPLICABLE TO ANY
  SUBJECT OR PATIENT

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The Adapted Multiple Point Stimulation Method
AMPS (Kadrie et al. 1976 Wang Delwaide 1995)

• 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
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The Adapted Multiple Point Stimulation Method
AMPS (Kadrie et al. 1976 Wang Delwaide 1995)

• 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.

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AMPSS-MUAP selection criteria
S-MUAP have to be evoked

• With distinct thresholds
• In an all-or-nothing manner
• Without any fractionation of the compound motor
  responses to successive suprathreshold stimuli
• In an orderly and reproducible manner

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AMPS advantages

• AMPS minimises alternation
• 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 is non- invasive and painless
• AMPS is a fast procedure
• No specific collection system or software is
  required

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AMPS advantages

• AMPS minimises alternation
• 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 is non- invasive and painless
• AMPS is a fast procedure
• No specific collection system or software is
  required

8
AMPS advantages

• AMPS minimises alternation
• 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 is non- invasive and painless
• AMPS is a fast procedure
• No specific collection system or software is
  required

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AMPS advantages
A. Thenar MUNE B. Average S-MUAP size
TEST 2
TEST 1
10
AMPS advantages
1000
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AMPS advantages

• AMPS minimises alternation
• 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 is non- invasive and painless
• AMPS is a fast procedure
• No specific collection system or software is
  required

12
AMPS advantages

• AMPS minimises alternation
• 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 is non- invasive and painless
• AMPS is a fast procedure
• No specific collection system or software is
  required

13
AMPS advantages

• AMPS minimises alternation
• 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 is non- invasive and painless
• AMPS is a fast procedure
• No specific collection system or software is
  required

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AMPS disadvantages

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

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AMPS disadvantages

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

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AMPS disadvantages

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

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AMPS disadvantages

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

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Conclusion

• Techniques using the incremental stimulation

McComas initial technique
MOTOR UNIT NUMBER
AMPS
Multiple Point Stimulation