Cognitive Rehabilitation in Alzheimer's Disease - A Conceptual and Methodological Review

Within the last 20 years, several standardized cognitive trainings have been developed aiming at the delay of cognitive decline in older people who are at risk of Alzheimer's Disease (AD) or in mild stages of dementia. The transfer of cognitive training effects into activities of daily living was very limited in most previous studies. Therefore, multimodal Cognitive Rehabilitation approaches have been designed that aim to improve the activities of daily living. These approaches also attempt to integrate the patient's psychopathological and behavioral status as well as social relationships into the treatment plan. Contrary to other approaches, CR mainly focuses on compensation rather than restoration of impaired functionality. In this review, we define CR conceptually, and derive specific criteria to evaluate current CR approaches for individuals with mild cognitive impairment (MCI) and AD dementia. In addition, we perform a critical, methodical analysis of available CR studies, reviewing their short- and long-term treatment effects. Findings suggest that CR approaches improve memory performance and competence of activity of daily living (ADL) in mildly cognitively impaired subjects (MCI), when compensatory, integrative, as well as interactive elements and domain specificity are taken into account. Interactive and individual aspects also appear to be relevant to sustain long-term effects. In AD dementia, similar results emerged, although with smaller effect sizes. The efficacy of individualized CR approaches was comparable with theory-based, manual-guided concepts as long as promoting interaction was part of the treatment. So far, only few randomized controlled studies of sufficient sample size are available. Future systematic efficacy studies need to consider precisely defined outcome variables. This is necessary before one can draw conclusions of how CR can be used for secondary prevention of AD dementia as well as AD treatment.