Repetitive hypoglossal nerve stimulation in myasthenia gravis.
OBJECTIVE
To assess the diagnostic efficacy of repetitive nerve stimulation (RNS) of the hypoglossal nerve in patients with myasthenia gravis (MG) and bulbar symptoms (dysphagia, dysarthria).


METHODS
Twenty patients with MG and 25 normal controls had RNS of the hypoglossal nerve. All patients also had single fibre electromyography (SFEMG) of the orbicularis oculi and RNS with recordings of the nasalis, trapezius and abductor pollicis brevis muscles.


RESULTS
All patients had positive SFEMG studies. Nine patients with bulbar symptoms had positive hypoglossal RNS, including 3 with negative RNS recordings in other muscles. Eleven patients with no bulbar symptoms showed negative hypoglossal RNS, including two with positive RNS recordings from other muscles.


CONCLUSIONS
Abnormal RNS of the hypoglossal nerve correlates well with bulbar dysfunction and further characterises the extent of neuromuscular transmission defect in MG patients.
Department of Neurology, Singapore General Hospital, Outram Road, Singapore 169608, Singapore. gnrlyl@sgh.com.sg
Y L
YL
Lo
T H
TH
Leoh
Y E
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Tan
M L
ML
Foo
Y F
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Dan
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Ratnagopal
D000328:Adult; D000368:Aged; D003680:Deglutition Disorders / Q000150:complications / Q000503:physiopathology; D004558:Electric Stimulation; D004576:Electromyography / Q000379:methods; D005154:Facial Nerve; D005260:Female; D006801:Humans; D007002:Hypoglossal Nerve / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation; D009157:Myasthenia Gravis / Q000150:complications / Q000503:physiopathology*; D009412:Nerve Fibers / Q000502:physiology; D009469:Neuromuscular Junction; D009801:Oculomotor Muscles / Q000294:innervation