The N200 abnormalities of auditory event-related potentials in patients with panic disorder.

Cognitive impairment in patients with panic disorder (PD) has been studied using event-related potentials (ERPs). However, previous studies obtained ERP data only at a few scalp sites, and seldom investigated N200 measurements from the difference waveforms. In the present study, auditory ERPs were recorded at 16 scalp sites during an active discrimination task of oddball paradigm. Fourteen PD patients (8 with agoraphobia; 6 without agoraphobia) were compared with 14 sex- and age-matched control subjects. For the nontarget waveforms, P2 amplitude was reduced in PD patients. For the target waveforms, a topographical difference between female PD patients and female controls was found for N200 amplitude, which attenuated in female PD patients over the parietal area. Two subcomponents of N200, N2a and N2b, were measured from the difference waveforms. A significant group difference was found for N2b amplitude, which reduced in PD patients compared with unaffected control subjects. It is suggested that N2b reduction reflects an abnormally controlled processing of stimulus information in PD.