The auditory P300 component of ERPs elicited during the oddball paradigm in type 2 diabetic patients

Background: There is increasing interest in the impact of diabetes mellitus on cognitive functioning. Several studies found evidence of decreased cognitive performance in type 2 diabetics (T2DM). Since the P300 component of event-related potentials (ERPs) provides valuable information concerning cognition, we studied this component of ERPs in T2DM. Methods: Auditory P300 event-related potentials (P300) were elicited in 43 T2DM patients and 29 age and sex-matched healthy volunteers by use of the auditory oddball paradigm, taking into account the age of the subjects, disease duration and the metabolic control. Results: Compared with controls, diabetics had significantly longer P300 latencies (F= 5.05, p= 0.026) and lower P300 amplitudes both in Cz and Pz electrode positions (F= 8.01, p= 0.005 and F= 13.67, p= 0.000 respectively). In addition, a significant inverse correlation between P300 latency and amplitude was observed in diabetics both in Cz and Pz electrode positions (r= -0.43, p= 0.003 and r= -0.39, p= 0.01 respectively), whereas essentially no relationship between amplitude and latency was observed for the control group. N200 and P300 latencies and the reduction in their amplitudes in Cz and Pz leads were not related to either disease duration or metabolic control. Conclusions: The observed electrophysiological abnormalities may reflect impairment of information processing and working memory, possibly associated with an accelerated ageing process. Our findings suggest that surface-recorded ERPs may be useful for detecting and monitoring the changes in brain function associated with diabetes mellitus.