Is Huntington's disease associated with deficits in theory of mind?

Authors

  • C. M. Eddy,

    Corresponding author
    1. School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
    • Department of Neuropsychiatry, BMSHFT The Barberry National Centre for Mental Health, Birmingham, UK
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  • S. Sira Mahalingappa,

    1. Department of Neuropsychiatry, BMSHFT The Barberry National Centre for Mental Health, Birmingham, UK
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  • H. E. Rickards

    1. Department of Neuropsychiatry, BMSHFT The Barberry National Centre for Mental Health, Birmingham, UK
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Dr. C. M. Eddy, Department of Neuropsychiatry, The Barberry National Centre for Mental Health, Birmingham and Solihull Mental Health NHS Foundation Trust, 25 Vincent Drive, Edgbaston, Birmingham B15 2FG, UK

Tel.: 0121 301 2290

Fax: 0121 301 2327

e-mail: clare.eddy@bsmhft.nhs.uk

Abstract

Objectives

People with Huntington's disease (HD) can exhibit interpersonal difficulties and deficits in recognizing emotional facial expressions. We investigated whether individuals with HD exhibit impairments in the understanding of other people's mental states, an aspect of Theory of Mind (ToM).

Materials and methods

Sixteen patients with HD and sixteen healthy controls completed two ToM tasks. One task involved recognising socially inappropriate behaviour and the other task required participants to judge complex mental states from photographs of people's eyes alone. To assess relationships between executive function and ToM, participants completed measures of verbal fluency, working memory and inhibition. The Problem Behaviours Assessment-short form (Neuropsychiatry Neuropsychol Behav Neurol, 14, 2001and 219) was completed twice using information from patients and their close relatives (where possible) to identify relationships between ToM impairment and behavioural problems.

Results

Patients with HD made significantly more errors on ToM tasks than controls, exhibiting difficulties in judging the social appropriateness of story character's behaviour and problems inferring complex mental states from photographs of people's eyes. Patients with HD also exhibited executive dysfunction. However, there was little evidence that executive impairments were related to ToM deficits. No correlations were apparent between problem behaviours and ToM errors.

Conclusions

HD is associated with deficits in ToM. Furthermore, some of patients' ToM difficulties appear independent of executive dysfunction.

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