Semantic memory impairment in dementia: A cross-cultural adaptation study.

BACKGROUND

Semantic memory deficits are frequently encountered in dementia and distinct patterns of semantic impairment characterize the subtypes of dementia. Life course and cultural experiences significantly influence semantic memory. Hence, there is a need to assess semantic memory using culturally appropriate tests, to aid accurate diagnosis of dementia and facilitate cross-cultural collaborative research.

AIMS

In this prospective study, we adapted and validated the Cambridge Semantic Memory (CSM) test battery to the Indian cultural context and studied the patterns of semantic memory impairment across dementia subtypes.

METHODS

The CSM battery was modified using standard methods and by incorporating culturally appropriate changes and new semantic categories relevant to India. The adapted Indian Semantic Memory (ISM) test battery was administered to a cohort of 121 subjects, consisting of controls and dementia: Alzheimer's disease (AD), progressive non-fluent aphasia (PNFA), semantic dementia (SD), and behavioral variant fronto-temporal dementia (BvFTD). Profile of semantic memory performance across groups was examined.

RESULTS

The ISM battery was found to be a valid measure of semantic memory. The novel semantic categories of gods/religious icons, vegetables, and food items added value to the diagnostic process. Distinct semantic memory profiles in SD, PNFA, AD, and BvFTD were demonstrated.

CONCLUSIONS

The cultural adaptation of a semantic memory battery for the Indian context provided sensitive evidence of semantic memory impairment in dementia and its subtypes. The clinical and research application of the ISM battery will enhance diagnostic evaluation that can aid in early and accurate identification of deficits and devising intervention strategies and enable research across cultures.