Cortical mechanisms mediating asterixis.
We describe a patient with chronic renal failure who suffered multifocal action-induced jerks. Electromyography (EMG) recorded the typical silence of asterixis. Back-averaging the EEG activity preceding the EMG silent periods in the forearm showed a biphasic wave antedating the asterixis by 23 ms. Somatosensory evoked potentials (SEPs) after median nerve stimulation were pathologically enlarged on both hemispheres. Brain-mapping of the biphasic wave preceding asterixis and the giant SEPs indicated a common origin in the sensorimotor cortex. This observation provides further documentation of a cortical origin for some types of asterixis in humans.
Artieda
J
J
Department of Neurology, Clinica Universitaria, University of Navarra, Pamplona, Spain.
Muruzabal
J
J
Larumbe
R
R
García de Casasola
C
C
Obeso
J A
JA
D001931:Brain Mapping / Q000295:instrumentation; D002540:Cerebral Cortex / Q000503:physiopathology*; D004569:Electroencephalography / Q000295:instrumentation*; D004576:Electromyography / Q000295:instrumentation*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000503:physiopathology*; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology; D009207:Myoclonus / Q000503:physiopathology; D009468:Neuromuscular Diseases / Q000503:physiopathology*; D011187:Posture / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013003:Somatosensory Cortex / Q000503:physiopathology