The influence of culture and cognitive reserve on the clinical presentation of behavioural-variant frontotemporal dementia.

Characterisation of the clinical profile of behavioural-variant frontotemporal dementia (bvFTD) has predominantly been based on Western samples. Some small studies have suggested that the clinical profile may differ in culturally and linguistically diverse populations. Additionally, there is evidence that patients from non-English speaking backgrounds may have more cognitive reserve, allowing them to tolerate more disease pathology before clinical symptoms emerge. This study aims to characterise the clinical profiles of patients with bvFTD from culturally diverse backgrounds. BvFTD patients were classified as Australian-born (Australian) or Culturally and Linguistically Diverse-English-speaking (CALD-English) and Culturally and Linguistically Diverse-Language Other Than English (CALD-LOTE). Clinical features, cognitive test performance and cognitive reserve were compared between groups. Voxel-based morphometry was used to examine the neural correlates of cognitive reserve. 107 patients with bvFTD (53 Australian, 36 CALD-English, 18 CALD-LOTE) and 51 controls were included. Analysis of neuropsychiatric features revealed more elation in Australian patients compared to CALD-English patients, with trends for CALD-LOTE patients to report more irritability. CALD-LOTE patients also had higher cognitive reserve and showed relatively greater verbal than non-verbal cognitive impairment. Neuroimaging analyses revealed that higher cognitive reserve was associated with lower integrity in the frontal-temporal regions associated with typical disease pathology in bvFTD. Our findings support the hypothesis that cognitive reserve may delay early cognitive decline in culturally and linguistically diverse patients, although these patients may still show poor verbal performance due to cultural testing biases. Clinically, these results highlight the need to consider cultural and linguistic background to inform the assessment of dementia.