Cognitive functioning and brain MRI in patients with type 1 and type 2 diabetes mellitus: a comparative study

BACKGROUND/AIMS: Diabetes mellitus (DM) may affect the central nervous system, resulting in cognitive impairments. It has been suggested that cognitive impairments are more pronounced in DM2 than in DM1, but studies that directly compare the effects of these 2 types of DM on cognition are lacking. METHODS: Forty patients with DM1 (mean duration: 34 years) were compared with 40 age- and education-matched patients who were known to have DM2 (mean duration: 7 years). Extensive neuropsychological assessment focussed on abstract reasoning, memory, attention and executive function, visuoconstruction and information processing speed. Psychological well-being was measured and brain MRIs were obtained. RESULTS: No systematic between-group differences were observed in neuropsychological measures or levels of psychological well-being. DM2 patients showed significantly more deep white matter lesions and cortical atrophy on MRI (p < 0.01). CONCLUSION: DM1 patients with more than 30 years of DM have a similar cognitive profile and better MRI ratings than age- and education-matched DM2 patients with only 7 years of DM.