Journal Article

Atrophy in distinct corticolimbic networks in frontotemporal dementia relates to social impairments measured using the Social Impairment Rating Scale

Bickart, Kevin C, Brickhouse, Michael, Negreira, Alyson, Barrett, Lisa Feldman, Dickerson, Bradford C, Sapolsky, Daisy

2014

Overview

Patients with frontotemporal dementia (FTD) often exhibit prominent, early and progressive impairments in social behaviour. We developed the Social Impairment Rating Scale (SIRS), rated by a clinician after a structured interview, which grades the types and severity of social behavioural symptoms in seven domains. In 20 FTD patients, we used the SIRS to study the anatomic basis of social impairments. In support of hypotheses generated from a prior study of healthy adults, we found that the relative magnitude of brain atrophy in three partially dissociable corticolimbic networks anchored in the amygdala predicted the severity of distinct social impairments measured using the SIRS. Patients with the greatest atrophy in a mesolimbic, reward-related (affiliation) network exhibited the most severe socioemotional detachment, whereas patients with the greatest atrophy in an interoceptive, pain-related (aversion) network exhibited the most severe lack of social apprehension. Patients with the greatest atrophy in a perceptual network exhibited the most severe lack of awareness or understanding of others’ social and emotional behaviour. Our findings underscore observations that FTD is associated with heterogeneous social symptoms that can be understood in a refined manner by measuring impairments in component processes subserved by dissociable neural networks. Furthermore, these findings support the validity of the SIRS as an instrument to measure the social symptoms of patients with FTD. Ultimately, we hope it will be useful as a longitudinal outcome measure in natural history studies and in clinical trials of putative interventions to improve social functioning.

• Publisher: BMJ Publishing Group LTD
• Subject: Aged / Alzheimer's disease / Aphasia / Atrophy - pathology / Atrophy - psychology / Behavior / Brain Mapping / Brain research / Case-Control Studies / Cerebral Cortex - pathology / Cognition & reasoning / Dementia / Etiquette / Female / Frontotemporal Dementia - complications / Frontotemporal Dementia - pathology / Frontotemporal Dementia - psychology / Humans / Interviews / Language / Limbic System - pathology / Male / Middle Aged / Neural Pathways - pathology / Patients / Psychiatric Status Rating Scales / Quantitative psychology / Reproducibility of Results / Social Behavior Disorders - complications / Social Behavior Disorders - diagnosis / Social Behavior Disorders - pathology / Social Behavior Disorders - psychology / Social research / Studies