Neurophysiological Study of Alzheimer’s Disease and Diabetes Mellitus Type 2 Patients. Is there a Common Link?

Abstract

Introduction:  Recent studies have shown that insulin resistance and deficiency, a marker of Diabetes mellitus type 2 (DM), interact with beta amyloid and tau protein phosphorylation, which are the basic neuropathological hallmarks of Alzheimer’s Disease (AD). Based on these results, it was recently proposed that AD might be considered as ‘Diabetes type 3’. Aim of the current study is to assess the cognitive function of DM patients and Mild cognitive impairment (MCI) patients with neurophysiological and neuropsychological measures and seek possible correlations. Methods: The study participants were divided into two groups: group 1 and group 2. Group 1 consisted of 24 DM patients (7 men, 17 women; age 70.6±6.5 (mean ± SD) years; age range 55-86 years. Group 2 consisted of 16 MCI patients  age 72.61±7.42 (mean ± SD)years; age range 58-89 years)   age-matched (t-value=1.06,  p=0.30) and gender matched (χ2=0.084,  p=0.772) with group 1 patients. All patients were assessed with auditory event-related potentials (AERPs) and neuropsychological tests, which include MMSE, MOCA, IADL, and HAMILTON depression scale. Latencies and amplitudes of the major AERP waves (N200, P300 and Slow Wave) were determined, Results: No statistically significant difference was observed in the AERP characteristics and the performance of the patients in the neuropsychological tests between the two groups (p>0.05). Conclusions: From the results of the current study, it appears that the higher cognitive functions of DM patients as assessed with ERPs and neuropsychological tests are affected in a similar way with that of MCI patients; a finding which supports the existence of common pathophysiological mechanisms between the two diseases.