Abstract
Twenty-two patients (16 affected by parkinsonian syndromes, 6 by other neurological diseases) and 12 age-matched controls were examined. Short-latency somatosensory evoked potentials were recorded from 30 scalp electrodes in the 45-52 msec following separate left and right median nerve stimulation at the wrist. Bit-colour maps were generated on a 4096 pixel matrix via quadratic interpolation. Peak latencies and amplitudes of the parietal, central and frontal components were evaluated. Moreover, the amplitude ratios between parietal and frontal components on the same hemiscalp and between peaks on homologous right and left scalp districts were taken into account. The unique significant difference between parkinsonians and controls was represented by a depressed frontal N30 wave. This peak was absent in 3 and reduced in 7 out of 16 parkinsonians, with an overall abnormality rate of 47% of the examined arms. Average maps pooling data of parkinsonians and controls confirmed the presence of reduced evoked activity for the whole duration of wave N30 on those mid- and parasgittal frontal districts where this peak is maximally represented in normals. A similar abnormality was found in 1 of the 6 non-parkinsonian neurological patients suffering from a meningioma of the falx compressing the left supplementary motor area. Possible pathophysiology of such wave N30 abnormalities in parkinsonians is discussed.
Original language | English |
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Pages (from-to) | 277-289 |
Number of pages | 13 |
Journal | Electroencephalography and Clinical Neurophysiology - Evoked Potentials |
Volume | 74 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1989 |
Keywords
- Bit-colour maps
- Parkinson disease
- Somatosensory evoked potentials
- Supplementary motor area
ASJC Scopus subject areas
- Clinical Neurology
- Neuroscience(all)