association between visual evoked potential and disease severity, disease duration and visual hallucination in patients with idiopathic parkinsonism

background: parkinson's disease (pd) is a neurodegenerative disorder impairing motor, verbal and other abilities. visual evoked potential (vep) assessment is a useful method for analysis of visual system and its function. the present study was designed in order to evaluate whether vep changes are associated with pd. m aterials and methods: in the present study, 100 subjects encompassing 40 patients with idiopathic parkinson’s disease (idiopathic pd) and 60 aged-matched controls were selected and assigned into case and control groups, respectively. vep analysis was conducted in either group and the results were compared. r es ults: in the present study, 16 patients (40%) showed prolonged p100 latency. p100 latency in the case group was significantly longer than in controls. p100 amplitude was significantly higher in case group than control. there were no significant association between prolonged vep and sex and diseases duration, in the participants. also from our participants who suffer from visual hallucination, p100 latency was significantly longer than in the controls.  there was a significant association between prolonged p100 latency and severity of disease in the case group. c onclusion: we suggest that prolonged vep latencies and amplitude are associated with pd and might be associated with a predisposition for visual hallucinations.