Do P1 and N1 evoked by the ERP task reflect primary visual processing in Parkinsons disease?
OBJECTIVES: To evaluate whether P1 and N1 evoked by ERP tasks could appropriately reflect primary visual processing in Parkinson’s disease (PD). METHODS: We recorded ERPs in 13 PD patients with duration of illness less than 5 years and 18 age-matched normal control subjects. P1 and N1 from Oz were evoked by a visual oddball and a delayed matching S1-S2 task. The effect of different events on P1 and N1 was studied. All patients were given an ECD-SPECT examination, and the SPECT images were overlaid on the 3D-MRI. The correlation of P1 or N1 to the regional cerebral blood flow (rCBF) was studied. RESULTS: P1 was not influenced by different events. There was no significant P1 differences between the PD and the normal group. N1 was significantly shorter and smaller in the patients than that in the normal group. N1 amplitude after the waveform subtraction (target-frequent) in the PD group did not show significant difference with that in the normal controls, nor with the N1 before the subtra
