Neuropsychological understanding of Cognitive Stimulation Therapy (CST)

Abstract

Objectives: The efficacy of Cognitive Stimulation Therapy (CST) in enhancing cognition in persons living with dementia is well established, nevertheless, its underlying mechanism is largely unknown. Knowledge of how non-pharmacological intervention causes changes will facilitate further improvement in design, and this pilot study aimed at exploring how CST may interact with brain and cognitive reserve to produce the generalized cognitive benefits Methods: We recruited 30 people living with dementia from five elderly community care and residential care facilities in Hong Kong. ADAS-Cog, Cornell Scale of Depression in Dementia (CSDD), and Holden Communication Scale (HCS) were used to assess their performance in cognition, mood and communication respectively at baseline before CST, 20 eligible participants were then recruited to the MRI part of the study. After baseline assessment, a 14-sessons CST, administered twice every week, were provided to the participants. Upon completion of CST, participants were invited back to undergo the same assessments they took at baseline. Results: Using clinical criteria defined per changes in ADAS-Cog total score, 14 (53.8%) participants with had maintained/improved cognition, including 6 (23.1%) participants showing improvement in cognitive performance. Baseline grey and white matter volume and years of work together explained 65% of cognitive gains after CST. The cognitive improvement was dissociated with neuropathological progression. Conclusions: This is a first study to explore the neuropsychological mechanisms of CST using MRI. Initial evidence support the active cognitive reserve framework by suggesting that it improves general cognition against the background of progressive neuropathology, in people who have a larger brain reserve and cognitive reserve at the time of intervention. This exploratory research provided a proof of concept of the reserve framework for understanding CST, with implication of early intervention and further research.