CLINICAL NEUROPHYSIOLOGIC FINDINGS IN PATIENTS WITH RAPIDLY PROGRESSIVE FAMILIAL PARKINSONISM AND DEMENTIA WITH PALLIDO-PONTO-NIGRAL DEGENERATION

Objective: To present clinical electrophysiologic studies performed on the pallido-ponto-nigral degeneration (PPND) family linked to chromos ome 17q21-22. Methods: Nine patients from this kindred were studied wi th 11 electroencephalograms (EEGs), 4 electroencephalographic backgrou nd frequency analysis (BFA) studies, 4 electromyographic recordings (E MGs) including nerve conduction studies (NCSs), 4 electromyographic mu ltichannel surface recordings (MSRs), one pattern visual evoked potent ial (VEP) study and one median nerve somatosensory evoked potential (S EP) study. Results: EEGs revealed normal findings early in the disease and diffuse slowing which became more prominent with disease progress ion. BFA studies demonstrated rapid decrease in mean parietal frequenc ies with disease progression. EMGs and NCSs showed no abnormalities. M SRs revealed action myoclonus and a dystonic process. Long loop reflex es were absent in resting hand muscles. VEPs and SEPs were normal. Con clusions: Clinical neurophysiologic studies were consistent with a cor tical and subcortical degenerative process. With clinical deterioratio n, there is a progressive decline in the mean parietal frequency and b ackground rhythms. Tremor studies were consistent with action myoclonu s and a dystonic process and did not show parkinsonian features of res ting tremor or agonist-antagonist cocontraction. There was no evidence of peripheral nerve involvement or slowing in central sensory pathway s. Electrophysiologic findings are characteristic for this illness. (C ) 1998 Elsevier Science Ireland Ltd. All rights reserved.