Strategic lesions in the anterior thalamic radiation and apathy in early Alzheimer's disease

Torso, Mario, Serra, Laura, Giulietti, Giovanni, Spanò, Barbara, Tuzzi, Elisa, Koch, Giacomo, Caltagirone, Carlo, Cercignani, Mara and Bozzali, Marco (2015) Strategic lesions in the anterior thalamic radiation and apathy in early Alzheimer's disease. PLoS ONE, 10 (5). e0124998. ISSN 1932-6203

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Abstract

BACKGROUND

Behavioural disorders and psychological symptoms of Dementia (BPSD) are commonly observed in Alzheimer's disease (AD), and strongly contribute to increasing patients' disability. Using voxel-lesion-symptom mapping (VLSM), we investigated the impact of white matter lesions (WMLs) on the severity of BPSD in patients with amnestic mild cognitive impairment (a-MCI).

METHODS

Thirty-one a-MCI patients (with a conversion rate to AD of 32% at 2 year follow-up) and 26 healthy controls underwent magnetic resonance imaging (MRI) examination at 3T, including T2-weighted and fluid-attenuated-inversion-recovery images, and T1-weighted volumes. In the patient group, BPSD was assessed using the Neuropsychiatric Inventory-12. After quantitative definition of WMLs, their distribution was investigated, without an a priori anatomical hypothesis, against patients' behavioural symptoms. Unbiased regional grey matter volumetrics was also used to assess the contribution of grey matter atrophy to BPSD.

RESULTS

Apathy, irritability, depression/dysphoria, anxiety and agitation were shown to be the most common symptoms in the patient sample. Despite a more widespread anatomical distribution, a-MCI patients did not differ from controls in WML volumes. VLSM revealed a strict association between the presence of lesions in the anterior thalamic radiations (ATRs) and the severity of apathy. Regional grey matter atrophy did not account for any BPSD.

CONCLUSIONS

This study indicates that damage to the ATRs is strategic for the occurrence of apathy in patients with a-MCI. Disconnection between the prefrontal cortex and the mediodorsal and anterior thalamic nuclei might represent the pathophysiological substrate for apathy, which is one of the most common psychopathological symptoms observed in dementia.

Item Type: Article
Schools and Departments: Brighton and Sussex Medical School > Neuroscience
Subjects: R Medicine > RC Internal medicine > RC0321 Neurosciences. Biological psychiatry. Neuropsychiatry > RC0346 Neurology. Diseases of the nervous system Including speech disorders
Depositing User: Patricia Butler
Date Deposited: 26 Nov 2015 20:02
Last Modified: 28 Jul 2017 23:50
URI: http://sro.sussex.ac.uk/id/eprint/54565

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