Evidence for Diabetic Encephalopathy

Abstract

Auditory brain stem responses were recorded in 20 normoacoustic long‐duration Type 1 diabetic patients (duration of diabetes 26 (range 13–46) years, age 44 (25–66) years) with peripheral neuropathy and retinopathy and in 19 sex‐matched normoacoustic short‐duration Type 1 diabetic patients (duration of diabetes 2 (0–6) years, age 23 (18–50) years) without clinical signs of neuropathy or microangiopathy. Abnormal brain stem auditory evoked responses were demonstrated in 40% of the long‐duration and in 5.3% of the short‐duration diabetic patients (p < 0.01). Interpeak latencies Jv—JI and JIII‐JI were significantly prolonged in both patient groups compared with the non‐diabetic control group (p < 0.01). Magnetic resonance imaging was performed in 16 of the long‐duration patients and in 40 age‐matched healthy volunteers on a whole body MR‐scanner. Subcortical and/or brain stem lesions with abnormally high signals were seen in 69% of the long‐duration Type 1 patients and in 12% of the healthy volunteers (p < 0.02). Neuropsychological examination including 17 tests for intelligence and cognition were performed in the 20 long‐duration Type 1 diabetic patients. The results indicated a performance close to that seen in a control group of healthy age‐matched control subjects. Our study demonstrates that a considerable proportion of long‐duration Type 1 diabetic patients suffering from retinopathy and peripheral neuropathy additionally have signs but no symptoms of central nervous system affection, diabetic encephalopathy.