Visual event-related potentials in progressive supranuclear palsy

The purpose of this study is to assess the cognitive function in early stages of progressive supranuclear palsy (PSP). Visual event-related potentials (visual ERPs) were examined in five non-demented patients with PSP and seven control subjects. ERPs were recorded using Figure (non-verbal) and Kanji (verbal) oddball paradigms. The latencies and amplitudes of N100 and P300 components were not significantly different between the PSP and control groups. However, the score of Hasegawa's dementia scale-revised (HDSR) was correlated with P300 amplitudes in the Figure task only in the PSP group. Since the P300 amplitude is related to attentional resources, changes in visual ERP induced by non-verbal stimuli might be associated with the attentional impairment even in early stages of PSP. In the Kanji task but not in the Figure task, the reaction time was prolonged in the PSP group, and positively correlated with the P300 latency in both groups. Visual verbal stimuli might be a good tool to evaluate the information processing in the early stages of PSP. Recording of visual ERP using both non-verbal and verbal stimuli could be helpful to assess a mild cognitive dysfunction in PSP.