Evoked potentials in Parkinson’s disease
Diagnosis of Parkinson’s disease ist not yet possible with neurophysiological methods. Therefore we investigated the median somatosensory and visually evoked potentials (SEP and VEP) to single and double stimulation, VEP using a special stimulation technique. Also we investigated the peripheral autonomic surface potentials (PASP) and motor evoked potentials (MEP) employing spinal and transcranial stimulation.
In Parkinson’s disease the absolute and relative refractory periods of cortical N 1 peak of SEP did not differ from that of normal subjects. After single stimulation the cortical N 20 latencies were only delayed in 2 of 17 cases. In 8 of 10 cases central conduction time was normal. The SEP peaks of brain stem were also normal and there was no correlation between symptomatology and SEP results.
The data of motor evoked potentials (MEP) demonstrated in all patients a normal central motor conduction time of 5.0 ms. In 3 of 10 patients PASP’s were delayed but not reduced. In 30% of patients the VEP data showed a significant delay of P 2 latency, often independently of clinical status or age. But there were no more P 2 alterations after special visual stimulation techniques.
KeywordsRefractory Period Motor Evoke Potential Conduction Time Somatosensory Evoke Potential Sympathetic Skin Response
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