Muscular fatigue and decremental response to repetitive nerve stimulation in X-linked spinobulbar muscular atrophy.
OBJECTIVE
We report decremental responses to repetitive nerve stimulation (RNS) in 11 patients diagnosed with X-linked spinobulbar muscular atrophy (X-SBMA).


METHODS
The compound muscle action potential (CMAP) of the right abductor digiti minimi (ADM) and trapezius (TZ) in response to a 3-Hz stimulation of the ulnar nerve at the wrist and accessory nerve at the neck were recorded by surface electrodes.


RESULTS
A decremental response to RNS was observed in 90.9% of the TZ muscle and 27.2% in the ADM muscle of patients with X-SBMA.


CONCLUSIONS
These electrophysiological features of X-SBMA are considered to be useful for diagnosis of X-SBMA. Furthermore, the waning phenomena that mostly appeared in the TZ muscle and increment of CMAP in RNS after the exercise also suggest a unique manifestation in X-SBMA.
Inoue
K
K
Department of Neurology, Kawasaki Medical School, Okayama, Japan. kenin_04@yahoo.co.jp
Hemmi
S
S
Miyaishi
M
M
Kutoku
Y
Y
Murakami
T
T
Kurokawa
K
K
Sunada
Y
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055534:Bulbo-Spinal Atrophy, X-Linked / Q000175:diagnosis* / Q000503:physiopathology*; D004558:Electric Stimulation / Q000379:methods*; D004568:Electrodiagnosis / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue / Q000502:physiology*