Electrodiagnostic findings in syringomyelia.
Electrodiagnostic abnormalities are well known to occur in syringomyelia although the findings are nonspecific. The objective of this work was to describe different types of spontaneous electromyographic (EMG) activity and reflex responses, which may be useful and more specific than conventional findings for the electrodiagnosis of syringomyelia. We studied 43 patients with syringomyelia by four-channel surface EMG and by recording the long-latency responses to distal stimulation of the median and tibial nerves. Continuous motor unit activity (CMUA) was found in 18 patients, synchronous motor unit potentials (SMUP) in 10, respiratory synkinesis (RS) in 5, and myokymic discharges in 4. Long-latency responses (LLR) with latencies ranging from 55 to 150 ms were found in 14 patients. Patients with syringomyelia thus show a wide variation of spontaneous EMG activity. An increase in excitability of spinal motor neurons is probably the basic underlying mechanism.
Nogués
M A
MA
Department of Clinical Neurophysiology, Raúl Carrea Institute for Neurological Research (FLENI), Montañeses 2325, 1428 Buenos Aires, Argentina. mnogues@fleni.org.ar
Stålberg
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E
D000293:Adolescent; D000328:Adult; D000368:Aged; D001418:Baclofen; D002648:Child; D004568:Electrodiagnosis; D004576:Electromyography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology; D020385:Myokymia / Q000503:physiopathology; D009431:Neural Conduction / Q000502:physiology; D015656:Respiratory Mechanics / Q000502:physiology; D013595:Syringomyelia / Q000175:diagnosis* / Q000503:physiopathology
D001418:Baclofen