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

Cognitive profiles in primary progressive aphasia variants: A cross-cultural Australian and Spanish investigation

BACKGROUND

The effect of cultural differences in neurodegenerative diseases is not well understood. We aimed to investigate the cognitive profiles of English- and Spanish-speaking individuals with primary progressive aphasia (PPA).

METHODOLOGY

A comparative cross-sectional study was conducted with 461 participants: 215 participants from Australia and 246 from Spain. The Australian cohort included 131 PPA patients: 37 nonfluent PPA (nfvPPA), 49 semantic PPA (svPPA), 45 logopenic (lvPPA) and 84 healthy controls (HC); the Spanish cohort had 162 PPA: 64 nfvPPA, 31 vsPPA, 67 lvPPA, and 84 HC. All participants completed the ACE-III and other tests assessing verbal working memory, attention/executive functioning, visuospatial constructional abilities and episodic memory. A subgroup of participants underwent structural brain MRI. Cognitive performance and neuroimaging were compared between groups.

RESULTS

The most salient differences between each variant and HC were similar in the Australian and Spanish cohort. However, the Spanish cohort scored lower than the Australian cohort in most cognitive tests evaluated (ACE-III total, attention, memory and visuospatial in nfvPPA; attention, memory, and visuospatial in svPPA; and memory, language, and visuospatial in lvPPA). Differences were particularly pronounced in the visuospatial subdomain among nonfluent variant PPA. Cortical thickness analysis showed the expected regional atrophy in each PPA variant, but with no greater atrophy in the Spanish cohort.

CONCLUSION

These findings revealed an impairment in other cognitive domains beyond language in PPA. However, Spanish patients exhibited more generalized cognitive involvement despite similar demographic and neuroimaging profiles, suggesting that cultural and resilience factors may influence PPA presentations.

Musicality and social cognition in dementia: clinical and anatomical associations

Human musicality might have co-evolved with social cognition abilities, but common neuroanatomical substrates remain largely unclear. In behavioural variant frontotemporal dementia, social cognitive abilities are profoundly impaired, whereas these are typically spared in Alzheimer's disease. If musicality indeed shares a neuroanatomical basis with social cognition, it could be hypothesized that clinical and neuroanatomical associations of musicality and social cognition should differ between these causes of dementia. We recruited 73 participants from the Amsterdam Dementia Cohort (n = 30 female; aged 50-78), of whom 23 had behavioural variant frontotemporal dementia, 22 Alzheimer's disease and 28 were healthy controls. Musicality was assessed using a music-emotion recognition test, melody, tempo, accent and tuning subscores, a musicality summed score, the identification of auditory hedonic phenotypes and music emotion induction using skin conductance responses. Social cognition was assessed across multiple levels, including emotion recognition, theory of mind, socio-emotional sensitivity and understanding of social norms. We used ANCOVA to investigate subgroup differences in musicality and social cognition and linear regressions to investigate associations between musicality and social cognition. All analyses were adjusted for age, sex, musical training and mini mental state examination. Finally, we performed voxel-based morphometry analyses on T1-weighted MRI to study whether regions for musicality and social cognition overlapped anatomically. We found that patients with behavioural variant frontotemporal dementia performed worse on music-emotion recognition (all P < 0.001) and tempo recognition (all P < 0.05) compared with Alzheimer's disease and on musicality summed score (all P = 0.02) compared to controls only. Furthermore, patients with behavioural variant frontotemporal dementia had lower mean skin conductance responses during emotion-inducing music, compared to Alzheimer's disease (all P < 0.045). Worse music emotion recognition scores were associated with worse facial emotion recognition (P < 0.0001), worse theory of mind (P = 0.0005) and worse understanding of social norms (P = 0.01). Melody and tempo recognition were associated with facial emotion recognition and theory of mind, and accent recognition was associated with the theory of mind. Music emotion recognition and tempo recognition were also associated with executive functions. Worse music emotion recognition, melody recognition, tempo recognition, facial emotion recognition and theory of mind scores were all related to atrophy in the anterior temporal regions and the fusiform gyri, which play a role in multisensory integration, and worse tempo recognition was associated with atrophy of the anterior cingulate cortex. These results support the idea that musicality and social cognition may share a neurobiological basis, which may be vulnerable in behavioural variant frontotemporal dementia.

Cognitive reserve in individuals with frontotemporal dementia: a systematic review

As the literature related to cognitive reserve (CR) in individuals with frontotemporal dementia (FTD) is only emerging, a clear consensus on the relationship among CR proxies, brain status, and clinical performance has not been reached. The primary aim of this systematic review was to examine the relationship among sociobehavioral proxies of CR, brain status, and clinical performance in individuals with various types of FTD. Additionally, characteristics of patient population, sociobehavioral proxies, disease severity tools, and brain status measures used were identified. The systematic review was conducted using comprehensive search terms in Medline, PsychINFO, PubMed, and Web of Science. Eligibility criteria were for studies to include at least one CR and one brain status measure for individuals with FTD, be published in a peer-reviewed journal, and be published in English. The Newcastle-Ottawa Quality Assessment Scale was used to assess study quality and bias risk. A total of 237 titles and abstracts were screened, with 13 studies meeting inclusion criteria. Together, these studies report 1,423 participants with FTD. Based on the included studies, partial support was demonstrated for CR in individuals with FTD when education, occupation, and leisure were utilized as CR proxies. The variability in results among studies could be related to the different tools used to measure CR, brain status, and disease severity. This review provides recommendations for future studies: incorporating longitudinal designs, in depth neuropsychological testing, consistent disease duration measure, and transparant statistical output reporting.

Musical experience influences socio-emotional functioning in behavioural variant frontotemporal dementia

Objectives

On phenotypic and neuroanatomical grounds, music exposure might potentially affect the clinical expression of behavioural variant frontotemporal dementia (bvFTD). However, this has not been clarified.

Methods

14 consecutive patients with bvFTD fulfilling consensus diagnostic criteria were recruited via a specialist cognitive clinic. Earlier life musical experience, current musical listening habits and general socio-emotional behaviours were scored using a bespoke semi-quantitative musical survey and standardised functional scales, completed with the assistance of patients' primary caregivers. Associations of musical scores with behavioural scales were assessed using a linear regression model adjusted for age, sex, educational attainment and level of executive and general cognitive impairment.

Results

Greater earlier life musical experience was associated with significantly lower Cambridge Behavioural Inventory (Revised) scores (β ± SE = -17.2 ± 5.2; p = 0.01) and higher Modified Interpersonal Reactivity Index (MIRI) perspective-taking scores (β ± SE = 2.8 ± 1.1; p = 0.03), after adjusting for general cognitive ability. Number of hours each week currently spent listening to music was associated with higher MIRI empathic concern (β ± SE = 0.7 ± 0.21; p = 0.015) and MIRI total scores (β ± SE = 1.1 ± 0.34; p = 0.014).

Discussion

Musical experience in earlier life and potentially ongoing regular music listening may ameliorate socio-emotional functioning in bvFTD. Future work in larger cohorts is required to substantiate the robustness of this association, establish its mechanism and evaluate its clinical potential.