Recognition memory for unfamiliar faces in Parkinson's disease: behavioral and electrophysiologic measures

We analyzed event-related potentials (ERPs) and behavioral measurements during a recognition memory task in 15 normal elderly subjects and 15 patients with Parkinson's disease (PD). To elicit ERPs unfamiliar faces were repeated immediately after initial presentation (at lag 0), after one intervening face (at lag 1) or at lag 3. Compared to normal controls, PD patients showed decreased accuracy in recognizing new unfamiliar faces. P170 latency and amplitude were similar between both groups. ERP amplitude between 300 and 500 ms after the stimulus in control subjects showed a positive shift (ERP repetition effect) for lag 0 at all sites and for lag 1 and 3 repetitions at the Fz site, while effects in the PD group were not noted at any site, even for the lag 0 repetition. ERP waveforms for the first presentation of faces in PD patients showed a significant positive shift compared to normal controls. These data suggest intact perception but impaired recognition memory for unfamiliar faces in PD. In addition, recognition memory deficits in PD may result from impairment of comparison of structural representations of presented faces with stored representations of faces known to the observer.