Relationship between incidental cerebral infarction and event related potential in patients with diabetes mellitus

Abstract

To evaluate the influences of incidental cerebral infarction and white matter lesions on cognitive function in patients with diabetes mellitus, we measured the event related potential (P300), number of incidental cerebral infarctions and T₂value of the frontal periventricular white matter using magnetic resonance imaging. The subjects comprised three groups : non-insulin dependent diabetes mellitus (NIDDM) cases without dementia or any history of cerebrovascular disease (the DM group : N =50); NIDDM cases with cerebrovascular disease (the DMCVD group : N =18); and normal controls (the NC group : N =23). The DM group was further subgrouped according to the number of incidental cerebral infarctions, as follows : those with no infarction (incidental cerebral infarction, ICI-0 group), a single infarction (ICI-1 group), and multiple infarctions (ICI-2 group). More foci of incidental cerebral infarctions were observed in the DMCVD group than in the DM group. Increases in the T₂value of the white matter and the P300 latency were closely correlated with the number of foci. In the DM group, Hasegawa's dementia scale (HDS) and mini-mental state examinations (MMS) were normal. However, an increased P300 latency suggested impaired cognitive function. These results indicate that the impairment of cognitive function in DM patients was caused not only by diabetic encephalopathy but also by incidental cerebral infarction.