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Periodic leg movements of sleep (nocturnal myoclonus): An electrophysiological study
Author(s) -
Wechsler Lawrence R.,
Stakes John W.,
Shahani Bhaghwan T.,
Busis Neil A.
Publication year - 1986
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.410190210
Subject(s) - myoclonus , nocturnal , electrophysiology , sleep (system call) , medicine , neuroscience , physical medicine and rehabilitation , psychology , computer science , operating system
Abstract Six patients with periodic leg movements of sleep (PLMS) were studied electrophysiologically. All patients had normal results on routine nerve conduction studies and electromyography. In 5 patients the blink reflex consisted of three components, and in 1 patient it consisted of four components, with two components being normal. The second component of their blink reflex did not habituate. Other abnormalities included long‐latency responses in the extremities in 2 patients, release of H‐reflexes from flexor hallucis brevis muscle in 2 patients, and an H max /M max ratio of 98% in 2 patients. One patient's median nerve somatosensory‐evoked response had a markedly enlarged P 22 wave. These electrophysiological abnormalities suggest a disorder of the central nervous system producing increased excitability of segmental reflexes. To produce increased excitability of both brainstem and spinal cord reflexes, the disorder must be operative at the pontine level or rostral to it. Since long‐latency components of blink reflexes occurred in all our patients, this may be a helpful diagnostic test when PLMS is suspected.