Clin EEG Neurosci. 2004 Apr;35(2):84-7
Niedermeyer E, Goldszmidt A, Ryan D.
Division of Neurology, Department of Internal Medicine, The Sinai Hospital, Baltimore, Maryland, USA.
Rolandic mu rhythm is usually limited to brief stretches of 0.5 to 2 sec duration.
Two observations of status-like enhancement of mu rhythm have prompted this report.
In both cases, 4-hour EEG-Video-Monitoring was used.
Clinically, the reported cases differed considerably.
Case 1 showed nearly continuous mu activity associated with general motionlessness: akinesia/amimia but without rigidity, caused by frontal lobe impairment due to multiple sclerosis.
In Case 2, an impressive mu-status started in drowsiness and was presumably attributable to levitiracetam (which had rendered seizure-free the patient's formerly severe case of temporal lobe epilepsy).
Mu rhythm status, thus far, is an unknown EEG entity.
It can be caused by impaired fronto-motor input and may also constitute a medication-effect (levitiracetam).