Does Cognitive Stimulation Therapy show similar efficacy in individuals with mild-to-moderate dementia from varying etiologies? An examination comparing its effectiveness in Alzheimer's disease and vascular dementia.

Objective: The effectiveness of the Cognitive Stimulation Therapy (CST) is well-documented. Nevertheless, the question of whether specific subgroups of individuals with dementia are more or less likely to benefit from this cognitive stimulation intervention remains unaddressed. Here, we directly compared the effectiveness of the Italian CST (CST-IT), delivered in a previous multicenter controlled clinical trial, across two distinct cohorts of individuals clinically diagnosed with Alzheimer's Disease (AD, = 30) and vascular dementia (VaD, = 27) in the mild-to-moderate stage.

Method: The impact of dementia subtype (AD vs VaD) on immediate (at intervention completion) benefits of CST-IT in general cognitive functioning, communicative abilities, mood, behavior and perceived quality of life was evaluated through linear mixed effects models. The frequency and severity of neuropsychiatric symptoms at baseline was inserted as a covariate due to the different behavioral profile in the two groups. Exploratory analyses also investigated the potential differential effect of dementia subtype on long-term benefits (three months after intervention).

Results: The CST-IT determined comparable immediate, clinically significant improvements in general cognition and communicative abilities. Dementia subtype influenced short-term benefits in depressive symptoms (with a greater decrease in AD patients) and quality of life (no significant impact in AD, and a small improvement in VaD). Such effects depended on diagnosis-related differences in neuropsychiatric symptoms. At long-term, benefits persisted in general cognition (though depending on the outcome considered). Improvements in narratives were seen in VaD, whereas communicative abilities in AD returned to baseline. Post-intervention gains in depressive symptoms persisted in AD, but not in VaD, although benefits in quality of life remained stable in the latter.

Conclusions: Different mechanisms of neuropsychological change after CST-IT were hypothesized for the different forms of dementia, particularly with respect to crucial outcomes such as language, mood and quality of life, with implications toward the delivery of such psychosocial intervention in clinical contexts.