Akademik Veri Yönetim Sistemi
Cerrahpasa Tip Dergisi, cilt.27, sa.2, ss.78-84, 1996 (Scopus, TRDizin)
Background and Design. - In idiopathic Parkinson's disease (PD), dopamine deficiency involves also the multisynaptic visual pathways resulting in a delay of visual evoked potentials' (VEPs) P100 latency. In this study, VEPs were recorded in 34 patients (63 eyes) with PD and in 8 healthy controls (12 eyes) using a reversing checkerboard pattern stimulus with different spatial frequencies and the effect of levodopa (LD) therapy, disease duration and severity on VEPs were investigated. Patients on LD treatment were divided into two subgroups according to their daily doses of LD (=<400 mg> and =<300 mg>). Results. - The P100 latency of. PD patients was found to be longer (124.03 ± 19.7 msec) than that of controls (113.9 ± 15.7 msec) (p<0.05) only when visual angle of 9.6 degrees/sec and pattern of small size were used. Patients without LD treatment (n=7) showed slightly more delayed VEPs than those on LD (n=27) (p>0.05), but this delay was significant when compared with the control group (p<0.02). Our data showed that PD patients on LD treatment were older than tended to have a mean stage of PD of Hoehn-Yahr scale and a longer disease duration than patients without treatment (p<0.05, p<0.05 and p<0.001 respectively). PD patients on LD with => 400 mg daily dose showed more prolonged VEP latencies than those of lower LD doses (p<0.02). We observed similar results of delayed VEPs with =>300 mg vs <300 mg daily doses of LD (p<0.01). VEPs latencies were not statistically different with regard to duration of LD therapy (shorter than 1.5 year vs longer), age of disease onset (before vs after 55 years), stage and staging of PD according to Hoehn-Yahr scale. Conclusions. - VEPs latencies were significantly delayed in patients with PD than controls. The beneficial effect of LD treatment on VEPs in PD has been reported previously, but according to our results this effect was significant only with lower doses of LD. Higher doses of LD resulted in a marked delay in VEPs contradicting with the clinical improvement.