Background Behavioural changes in amyotrophic lateral sclerosis (ALS) are heterogeneous. The study aim was to identify the behavioural profiles of non-demented patients with ALS and their neuroimaging correlates and to elucidate if they are comparable to those reported in studies of the behavioural-variant of frontotemporal dementia (bvFTD).
Methods Behavioural changes of 102 non-demented patients with ALS were assessed through the Frontal Behavioural Inventory (FBI), a 24-item scale assessing different behavioural modifications, mainly chosen from the core clinical features of FTD. Principal component analysis (PCA) was used to detect distinct clusters of behavioural changes based on FBI subscores. The cortical thinning related to each behavioural profile was analysed in 29 patients with ALS. Cronbach’s α was used to test the reliability of bvFTD-related FBI clustering in our cohort.
Results Sixty patients with ALS had FBI score≥1. PCA identified three phenotypic clusters loading on disinhibited/hostile, dysexecutive and apathetic FBI subscores. Imaging analyses revealed that the thinning of bilateral orbitofrontal cortex was related to apathy, the right frontotemporal and cingular cortex to the disinhibited/hostile profile and the left precuneus cortex to the dysexecutive behaviours. The bvFTD-associated aggressive profile reliably applied to our cohort.
Conclusions In non-demented patients with ALS, different behavioural profiles could be identified. The right frontotemporal and cingular cortex thinning was the hallmark of the behavioural profile mostly overlapping that described in bvFTD. Our findings provide the unbiased identification of determinants relevant for a novel stratification of patients with ALS based on their behavioural impairment, which might be useful as proxy of cognitive decline.
- amyotrophic lateral sclerosis
- frontotemporal dementia
- cortical thickness
- principal component analysis
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Contributors MC, EDB and VEC collected data. VEC acquired and analysed neuroimaging data. MC designed the study and performed statistical analyses. MC, SFC and GL gave important intellectual content in data interpretation. MC, EDB and VEC wrote a draft of the manuscript. SFC and GL revised the final version of the manuscript for intellectual content.
Funding The study was financed by institutional funding (IRCCS Foundation ‘Carlo Besta’ Neurological Institute, Ricerca Corrente, Italian Ministry of Health), Fondazione Regionale per la Ricerca Biomedica (FRRB) Regione Lombardia and Fondazione Italiana di Ricerca per la SLA—Sclerosi Laterale Amiotrofica (AriSLA).
Competing interests None declared.
Patient consent Not required.
Ethics approval Institutional Board.
Provenance and peer review Not commissioned; externally peer reviewed.
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