Alzheimer’s disease and Type 2 Diabetes Mellitus: Similar Memory and Executive Functions Impairments?

Alzheimer´s disease (AD) accounts for more than half of all the cases of dementia. T2DM is a highly prevalent chronic metabolic condition among older adults, and is considered a risk factor to develop AD and other types of dementia. Currently, the incidence of both, AD and type 2 Diabetes Mellitus (T2DM) is a major public health problem in developed countries. Given the similarities between the metabolic and vascular changes occurring in the brain of diabetic patients and in AD patients, a relevant question is whether a series of main cognitive abilities, including episodic memory, working memory and executive functions are similarly impaired in AD and T2DM patients. Recent research has shown a clear dissociation between implicit and explicit memory. Results have shown intact implicit memory in both clinical groups, similar to that of healthy older adults, and impaired episodic (explicit) memory in both groups of patients, especially in ADs. At the same time, visuospatial and verbal working memory (updating and maintenance of information assessed with n-back tasks) showed significant declines in AD and T2DM but larger in ADs. Executive control assessed with the Wisconsin Card Sorting Test (WCST) showed similar declines in both groups of patients. Neuropsychologists and clinicians need to take into account the decline of long-term episodic memory and executive control processes in T2DM for their negative impact on treatment management. At the same time, the spared implicit memory of AD and T2DM patients could be used to support rehabilitation.