VEP AND ERP ABNORMALITIES IN CHILDREN AND ADOLESCENTS WITH PREPUBERTAL ONSET OF INSULIN-DEPENDENT DIABETES-MELLITUS

Visual evoked sensory (VEP) and event-related potentials (ERP) were as sessed in 29 adolescents viith insulin-dependent diabetes mellitus (ID DM) and in 29 controls matched for age and gender. Data were compared with clinical and psychometric measures, age at onset, duration of dis ease, and metabolic control. Analysis revealed no latency differences for the first cortical VEP component (P50) but a steadily increasing l atency delay for subsequent VEP (N80, P100, N150, P200) and ERP compon ents (P300) in the IDDM group compared to healthy controls. IDDM subje cts showed highly significant latency prolongations (p<0.001) for P100 , N150 and P200 and P300 compared with healthy controls. A pathologica l VEP/ERP latency delay of more than 3 SD above the reference value ra nge tvas observed in 21 IDDM patients (72.4 %). Psyche metric outcome measures in IDDM subjects showed no significant performance deficits o n the Raven SPMs relative to non-diabetic controls. In contrast to VEP and ERP anomalies, which were highly interrelated, there was no tende ncy for neurophysiological and psychometric abnormalities to be contem porarily present. Neither electrophysiological nor psychometric measur es were correlated with age at onset, IDDM duration, quality of metabo lic control, or the presence of peripheral neuropathy. These findings give evidence that 1) higher cognitive functions are frequently affect ed in adolescents even with prepubertal IDDM onset, 2) neurophysiologi cal ERP analysis seems to detect minor neurocognitive restrictions, pr esently not affecting psychometric outcome, 3) altered neurophysiologi cal parameters were present in more than 70% of IDDM subjects studied, and 4) functional CNS disturbances affecting neurocognition are appar ently not correlated with metabolic parameters previously thought to b e important predictors of CNS outcome, suggesting the presence of mult ifactorial influences affecting neurocognition in IDDM subjects.