Background: Mild cognitive impairment (MCI) has been suggested to represent a prodromal stage of dementia and confers a high risk for conversion to Alzheimer´s disease (AD). In this study, we examined the predictive value of depressive symptoms and neuropsychological variables on conversion of MCI to AD.
Methods: Our sample consisted of 260 MCI patients seen at the Psychiatric Memory Clinic of Innsbruck between 2005 and 2015. Neuropsychological and clincal data of the baseline and at least one follow-up visit were collected retrospectively. Depression was assessed using the Geriatric Depression Scale (GDS). Univariate and logistic regression analyses were performed.
Results: Of the 260 patients (mean age 71.5±7.7 years) 83 (32%) converted to AD within a mean follow-up time of 3.2± 2.2 years. The univariate ananlysis showed higher age and GDS score and lower MMSE, verbal memory, Boston naming and Clox I test scores at baseline in converting MCI compared to stable MCI patients. However, logistic regression analysis revealed solely depression, MMSE and verbal memory scores as significant predictors of imminent conversion from MCI to AD.
Conclusion: Our results support the previously reported predictive value of deficits in verbal memory and lower MMSE scores in the progression of AD. In addition, we found a strong negative influence of depression on MCI patients before imminent conversion to AD. These results emphasise the importance of depressive symptoms in early stages of AD and their possible impact on conversion from MCI to dementia stage.