Cognitive stimulation therapy (CST): neuropsychological mechanisms of change.

BACKGROUND Cognitive stimulation therapy (CST) is an evidence-based psychosocial intervention for people with dementia consisting of 14 group sessions aiming to stimulate various areas of cognition. This study examined the effects of CST on specific cognitive domains and explored the neuropsychological processes underpinning any effects. METHODS A total of 34 participants with mild to moderate dementia were included. A one-group pretest-posttest design was used. Participants completed a battery of neuropsychological tests in the week before and after the manualised seven-week CST programme. RESULTS There were significant improvement pre- to post-CST group on measures of delayed verbal recall (WMS III logical memory subtest - delayed), visual memory (WMS III visual reproduction subtest - delayed), orientation (WMS III information and orientation subscale), and auditory comprehension (Token Test). There were no significant changes on measures of naming (Boston Naming Test-2), attention (Trail Making Test A/Digit Span), executive function (DKEFS verbal fluency/Trail Making Test B), praxis (WMS III visual reproduction - immediate) or on a general cognitive screen (MMSE). CONCLUSIONS Memory, comprehension of syntax, and orientation appear to be the cognitive domains most impacted by CST. One hypothesis is that the language-based nature of CST enhances neural pathways responsible for processing of syntax, possibly also aiding verbal recall. Another is that the reduction in negative self-stereotypes due to the de-stigmatising effect of CST may impact on language and memory, domains that are the primary focus of CST. Further research is required to substantiate these hypotheses.