[Cortical and spinal evoked potentials in parkinsonism. Part I. Visual potentials evoked with a checkerboard pattern].

In 21 patients with parkinsonism and 20 healthy controls visual potentials evoked with checker pattern used as an alternating stimulus were studied. The left and right eye were examined separately recording visual cortical responses in the central occipital area. The analysed elements included the latency of the first highest positive wave P100 and the amplitude of the P100/N120 complex. Prolongation of the mean latency of P100 was found in patients with parkinsonism, but it was not significant statistically. No differences were found of the P100/N120 amplitude in the group with parkinsonism in relation to healthy controls. In the patients with parkinsonian syndrome (mainly of atherosclerotic origin) the mean latency of the visual potentials was longer and the amplitude was lower than in cases of Parkinson's disease. Attention is called to the high variability of the visual evoked potentials related to the clinical state and origin of the disease (parkinsonian syndrome and Parkinson's disease).