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Abstract
Background A proportion of patients with behavioural variant frontotemporal dementia (bvFTD) develop amyotrophic lateral sclerosis (ALS). It is currently unknown whether the behavioural and cognitive syndrome in bvFTD with ALS (ALS-FTD) is indistinguishable from that of bvFTD alone.
Methods A retrospective cohort of 241 patients with clinical diagnoses of bvFTD (n=185) or ALS-FTD (n=56) was examined with respect to behavioural, cognitive and neuropsychiatric symptoms. Features were rated as present or absent based on information recorded from clinical interviews and detailed neuropsychological assessment.
Results A number of behavioural and affective changes were reported more frequently in bvFTD than ALS-FTD: social disinhibition (p<0.001), inertia (p<0.001), loss of sympathy and empathy (p=0.008), repetitive behaviours (p<0.001) and dietary changes (p<0.001). Warmth of affect demonstrated in the clinic setting was reported more often in ALS-FTD than bvFTD (p<0.001). Executive impairments occurred equally in both groups. Language impairments were more common in ALS-FTD than bvFTD: agrammatism (p<0.017) and impaired sentence comprehension (p<0.036). Psychotic features were relatively rare and did not distinguish the groups.
Conclusions Our findings suggest differences between bvFTD and ALS-FTD. In particular, while changes in social behaviour are prominent in bvFTD alone, there may be a comparatively greater degree of language impairment in ALS-FTD. Prospective exploration of the pattern of differences between these groups will be essential. Identification of a distinct neuropsychological phenotype in ALS-FTD may have clinical implications for early diagnosis, disease management and care planning and theoretical implications for our understanding of the relationship between ALS and FTD.
- amyotrophic lateral sclerosis
- frontotemporal dementia
- aphasia
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Footnotes
Contributors JAS: study design, data acquisition and analysis and drafting of the manuscript. JCT: study design, acquisition/co-rating of data, interpretation, critical review, revision and approval of the manuscript. MJ: acquisition of clinical data, revision, critical review and approval of the manuscript. JMH, AMTR, TL and DN: acquisition of clinical data, critical review and approval of the manuscript. DMAM: analysis and interpretation of pathological data, critical review and approval of the manuscript. JSS: conception and design, acquisition of clinical data, revision and approval of the manuscript.
Funding JAS is funded by the Motor Neurone Disease Association through a PhD Studentship award. The Manchester brain donation scheme and work of the Manchester Brain Bank is supported by the Alzheimer’s Research UK and the Alzheimer’s Society through the Brains for Dementia Research Initiative.
Competing interests None declared.
Patient consent This is a retrospective study which used clinical data from patients who had previously attended the clinic. All participants have previously consented to the storage and use of their data in future research studies via the ‘Clinical data in research into degenerative brain disease’ study (Rec ref. 09/H0906/53+5).
Ethics approval Ethical approval was obtained from the Newcastle and Tyneside Ethics committee ‘Clinical data in research into degenerative brain disease’ Rec ref. 09/H0906/53+5, and ‘Manchester Brain Bank’ Rec ref. 09/H0906/52+5.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Requests for data sharing should be made in writing to the corresponding author. Requests will be considered individually at departmental research/clinical governance meetings.