2. 57EMG: Myasthenia?
Patient with bilat ptosis but no arm or leg weakness. RNS in nasalis and deltoid normal.
SFEMG in orb oculi and frontalis normal.
1. Ocular MG
2. Generalized MG
3. Myopathy
4. Bell palsy
Normal SFEMg findings are strong indications that symptoms are NOT MG. In this case, it may be
a myopathy, often with very little of jitter abnormalities
3. 57EMG: Myasthenia?
Patient with bilat ptosis but no arm or leg weakness. RNS in nasalis and deltoid normal.
SFEMG in orb oculi and frontalis normal.
1. Ocular MG
2. Generalized MG
3. Myopathy
4. Bell palsy
Normal SFEMg findings are strong indications that symptoms are NOT MG. In this case, it may be
a myopathy, often with very little of jitter abnormalities
4. Q 40. Which is the optimal time for maximal voluntary
activation in RNS tests in MG and LEM respectively?
1
5. Q 40. Which is the optimal time for maximal voluntary
activation in RNS tests in MG and LEM respectively?
45-60 sec to provoke MG exhaustion
10 sec to see LEM facilitation
1
6. RNS
• Is the head moving when you perform correctly RNS from trapezius
muscle (stim behind the sternocleid muscles)? NO, move stim
• Is it normal to have some degree of “biting” when you perform RNS
of the nasalis muscle? If not, what to do?
No, direct stim of masseter muscle, move stim
1
7. RNS
• Is the head moving when you perform correctly RNS from trapezius
muscle (stim behind the sternocleid muscles)? NO, move stim
• Is it normal to have some degree of “biting” when you perform RNS
of the nasalis muscle? If not, what to do?
No, direct stim of masseter muscle, move stim
1
8. Q 43. Tests of LEM?
The important finding is strong facilitation (> 60% amplitude
increase)
This is accomplished by
1. 10 sec voluntary activation
or
2. Stim 20 (-50) Hz for 1 sec. Note, the facilitation should be
assessed from the amplitude obtained after first single
stimulus after the train.
(during the train the muscle is shortening, which changes the
amplitude by up to 40%)
8
9. Q 43. Tests of LEM
The important finding is strong facilitation (> 60% amplitude
increase)
This is accomplished by
1. 10 sec voluntary activation
or
2. Stim 20 (-50) Hz for 1 sec. Note, the facilitation should be
assessed from the amplitude obtained after first single
stimulus after the train.
(during the train the muscle is shortening, which changes the
amplitude by up to 43%)
9
