CHANGES IN AUDITORY P300 EVENT-RELATED POTENTIALS AND BRAIN-STEM EVOKED-POTENTIALS IN DIABETES-MELLITUS

To investigate the influence of diabetes mellitus on higher cognitive functions electrophysiologically, we studied auditory P300 event-relat ed potentials (P300) in 40 NIDDM patients, taking into account wave I- V latencies (I-V) in auditory brainstem evoked potentials, clinical pa rameters and head MRI findings. Compared with 20 controls, diabetics h ad significantly longer P300 and I-V latencies. P300 latencies in diab etics correlated with neither I-V, HbA(1), blood glucose levels, nor d isease duration. Of the 13 diabetics investigated neuroradiologically, four had lacunar infarcts with prolonged electrophysiological values. The remaining nine had normal MRI scans, but their physiological para meters were still significantly longer than those of controls. These f indings suggest that NIDDM can independently alter higher cognitive an d the central auditory pathway functions. Our data also suggest that t hese alterations occur regardless of the recent metabolic derangement and disease duration. Cerebrovascular ischemia, if present, also appea rs to contribute in part to cognitive alterations.