Differentiating between right-lateralised semantic dementia and behavioural-variant frontotemporal dementia: an examination of clinical characteristics and emotion processing

Jody Kamminga; Fiona Kumfor; James R Burrell; Olivier Piguet; John R Hodges; Muireann Irish

doi:10.1136/jnnp-2014-309120

Differentiating between right-lateralised semantic dementia and behavioural-variant frontotemporal dementia: an examination of clinical characteristics and emotion processing

J Neurol Neurosurg Psychiatry. 2015 Oct;86(10):1082-8. doi: 10.1136/jnnp-2014-309120. Epub 2014 Dec 15.

Authors

Jody Kamminga¹, Fiona Kumfor², James R Burrell², Olivier Piguet², John R Hodges², Muireann Irish³

Affiliations

¹ Neuroscience Research Australia, Sydney, New South Wales, Australia School of Psychology, University of New South Wales, Sydney, New South Wales, Australia.
² Neuroscience Research Australia, Sydney, New South Wales, Australia School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, New South Wales, Australia.
³ Neuroscience Research Australia, Sydney, New South Wales, Australia School of Psychology, University of New South Wales, Sydney, New South Wales, Australia Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, New South Wales, Australia.

PMID: 25511791
DOI: 10.1136/jnnp-2014-309120

Abstract

Background and purpose: Right-lateralised semantic dementia (right SD) and behavioural-variant frontotemporal dementia (bvFTD) appear clinically similar, despite different patterns of underlying brain changes. This study aimed to elucidate distinguishing clinical and cognitive features in right SD versus bvFTD, emphasising emotion processing and its associated neural correlates.

Methods: 12 patients with right SD and 19 patients with bvFTD were recruited. Clinical features were documented. All patients were assessed on standardised neuropsychological tests and a facial emotion processing battery. Performance was compared to 20 age-matched and education-matched controls. Grey matter intensity was related to emotion processing performance using whole-brain voxel-based morphometry analysis.

Results: Patients with right SD exhibited disproportionate language dysfunction, prosopagnosia and a suggestion of increased obsessive personality/behavioural changes versus patients with bvFTD. In contrast, patients with bvFTD demonstrated pronounced deficits in attention/working memory, increased apathy and greater executive dysfunction, compared to patients with right SD. Decreased empathy, disinhibition and diet changes were common to both dementia subtypes. Emotion processing deficits were present in both FTD syndromes but were associated with divergent patterns of brain atrophy. In right SD, emotion processing dysfunction was associated with predominantly right medial and lateral temporal integrity, compared to mainly left temporal, inferior frontal and orbitofrontal and right frontal gyrus integrity in bvFTD.

Conclusions: This study demonstrates comparable deficits in facial emotion processing in right SD and bvFTD, in keeping with their similar clinical profiles. These deficits are attributable to divergent neural substrates in each patient group, namely, right lateralised regions in right SD, versus predominantly left lateralised regions in bvFTD.

Keywords: DEMENTIA; FRONTAL LOBE; MRI; NEUROPSYCHOLOGY.

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Publication types

Comparative Study
Research Support, Non-U.S. Gov't

MeSH terms

Aged
Atrophy
Brain / pathology
Cognition
Dementia / diagnosis*
Dementia / psychology*
Diagnosis, Differential
Emotions*
Face
Female
Frontotemporal Dementia / diagnosis*
Frontotemporal Dementia / psychology*
Functional Laterality
Gray Matter / pathology
Humans
Magnetic Resonance Imaging
Male
Middle Aged
Neuropsychological Tests
Social Perception