Neuroanatomical profiles of personality change in frontotemporal lobar degeneration

Abstract

Background: The neurobiological basis of personality is poorly understood. Frontotemporal lobar degeneration (FTLD) frequently presents with complex behavioural changes, and therefore potentially provides a disease model in which to investigate brain substrates of personality.

Aims: To assess neuroanatomical correlates of personality change in a cohort of individuals with FTLD using voxel-based morphometry (VBM).

Method: Thirty consecutive individuals fulfilling consensus criteria for FTLD were assessed. Each participant's carer completed a Big Five Inventory (BFI) questionnaire on five key personality traits; for each trait, a change score was derived based on current compared with estimated premorbid characteristics. All participants underwent volumetric brain magnetic resonance imaging. A VBM analysis was implemented regressing change score for each trait against regional grey matter volume across the FTLD group.

Results: The FTLD group showed a significant decline in extraversion, agreeableness, conscientiousness and openness and an increase in neuroticism. Change in particular personality traits was associated with overlapping profiles of grey matter loss in more anterior cortical areas and relative preservation of grey matter in more posterior areas; the most robust neuroanatomical correlate was identified for reduced conscientiousness in the region of the posterior superior temporal gyrus.

Conclusions: Quantitative measures of personality change in FTLD can be correlated with changes in regional grey matter. The neuroanatomical profiles for particular personality traits overlap brain circuits previously implicated in aspects of social cognition and suggest that dysfunction at the level of distributed cortical networks underpins personality change in FTLD.

Fig. 1

Personality trait scores in participants with frontotemporal lobar degeneration (present and premorbid) and controls. (a) Behavioural variant frontotemporal dementia subgroup; (b) progressive non-fluent aphasia subgroup; (c) semantic dementia subgroup; (d) control group. BFI, Big Five Inventory; E, extraversion; A, agreeableness; C, conscientiousness; N, neuroticism; O, openness.

Fig. 2

Personality change data in participants with frontotemporal lobar degeneration and controls. BFI, Big Five Inventory; E, extraversion; A, agreeableness; C, conscientiousness; N, neuroticism; O, openness.

Fig. 3

Voxel-based morphometry correlates of personality change in frontotemporal lobar degeneration (FTLD). See Fig. DS1 for a colour version of this figure. For each personality trait, panels show statistical parametric maps of associated grey matter loss (GM loss) or relative grey matter preservation (GM). Maps have been rendered on the mean T -weighted normalised brain image for the FTLD group; the left hemisphere is presented on the left. For display purposes, maps are thresholded at P<0.001 uncorrected for all results. T-scores of grey matter change are coded as indicated on the colour bar (lower left). T-scores of grey matter change are coded as indicated on the greyscale bar (lower left).