Emotion processing deficits distinguish pure amyotrophic lateral sclerosis from frontotemporal dementia

Abstract

Amyotrophic lateral sclerosis (ALS) is a multisystem disease that overlaps with frontotemporal dementia (FTD). Although FTD patients exhibit prominent deficits in emotion perception and social cognition, these domains have received relatively little attention in ALS. Moreover, direct comparisons between ALS and FTD on emotion processing tasks remain lacking. Twenty-nine patients with ALS (16 with coexisting FTD (FTD-ALS) and 13 without dementia), 25 behavioural variant FTD patients and 30 healthy controls completed neuropsychological and emotion tasks (Ekman Caricatures and the TASIT). Both ALS and FTD patient groups showed significant deficits on the emotion tasks compared to controls. After dividing ALS patients into those with and without FTD, only the patients with coexisting FTD (FTD-ALS) were impaired. FTD-ALS and FTD patient groups displayed similar levels of impairment, even after controlling for measures of general cognition, and demonstrated similar profiles across different types of emotions. We conclude that patients with FTD-ALS and FTD show similar, significant impairments in emotional processing. By contrast, ALS patients without dementia exhibit preserved emotion processing. Performance on emotion processing tasks may provide a useful clinical tool in identifying those with early FTD-ALS.

Key words::

• Emotion
• cognitive impairment
• frontotemporal dementia
• ALS-FTD

Acknowledgements

We thank all our patients and carers who participated in this study, as well as the multidisciplinary teams of Motor Neurone Disease clinics (Prince of Wales Hospital and St. Joseph's Hospital) and The Motor Neurone Disease Association of New South Wales.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Study funding was supported by the Australian Research Council Federation Fellowship (J. R. Hodges) and the ARC Centre of Excellence in Cognition and its Disorders. O. Piguet is supported by a National Health and Medical Research Council Clinical Career Development Fellowship. P. Lillo was a recipient of a CONICYT Scholarship provided by the Government of Chile. M. Kiernan and J.R. Hodges are in receipt of National Health and Medical Research Project and Program Grant funding.