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White Matter Correlates of Cognitive Impairment in Essential Tremor

White Matter Correlates of Cognitive Impairment in Essential Tremor BACKGROUND AND PURPOSE: Impairment of cognitive functions occurs in essential tremor, though the mechanism is largely unknown. The aim of this study was to find microstructural correlates of cognitive dysfunction seen in essential tremor by using DTI and neuropsychological assessment. MATERIALS AND METHODS: Fifty-five patients with essential tremor and 55 matched healthy controls were evaluated. Essential tremor was diagnosed by using the National Institutes of Health criteria. Subjects were assessed by using a structured neuropsychological battery. DTI data were acquired by using 3T MR imaging and were analyzed by using tract-based spatial statistics. Fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity were analyzed. RESULTS: Patients were considered cognitively impaired when the test score was 1.5 SDs below or above the mean of healthy controls (depending on the type of test) in ≥3 neuropsychological tests. Patients with cognitive impairment had significantly higher mean diffusivity, radial diffusivity, and axial diffusivity values in the bilateral frontoparietal regions. In patients with cognitive impairment, mean diffusivity, radial diffusivity, and axial diffusivity showed correlations with various neuropsychological test scores. Executive function correlated with DTI measures of the frontal white matter, cingulum, inferior superior longitudinal and uncinate fasciculi, anterior thalamic radiations, and posterior lobe of the cerebellum. Visuospatial function correlated with the right parieto-occipital lobe, whereas visual-verbal memories correlated with the anterior thalamic radiations, inferior longitudinal and uncinate fasciculi, and the posterior lobe of the cerebellum. No significant correlations were found between fractional anisotropy and any of the neuropsychological test scores. CONCLUSIONS: The present study demonstrates a correlation between neuropsychological test scores and DTI measures, suggesting a neuroanatomic basis for cognitive impairment seen in patients with essential tremor. ABBREVIATIONS: ET essential tremor ETCI ET with cognitive impairment ETNCI ET without cognitive impairment HC healthy controls TBSS tract-based spatial statistics http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png American Journal of Neuroradiology American Journal of Neuroradiology

White Matter Correlates of Cognitive Impairment in Essential Tremor

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Publisher
American Journal of Neuroradiology
Copyright
Copyright © 2015 by the American Society of Neuroradiology.
ISSN
0195-6108
eISSN
1936-959X
DOI
10.3174/ajnr.A4138
pmid
25339653
Publisher site
See Article on Publisher Site

Abstract

BACKGROUND AND PURPOSE: Impairment of cognitive functions occurs in essential tremor, though the mechanism is largely unknown. The aim of this study was to find microstructural correlates of cognitive dysfunction seen in essential tremor by using DTI and neuropsychological assessment. MATERIALS AND METHODS: Fifty-five patients with essential tremor and 55 matched healthy controls were evaluated. Essential tremor was diagnosed by using the National Institutes of Health criteria. Subjects were assessed by using a structured neuropsychological battery. DTI data were acquired by using 3T MR imaging and were analyzed by using tract-based spatial statistics. Fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity were analyzed. RESULTS: Patients were considered cognitively impaired when the test score was 1.5 SDs below or above the mean of healthy controls (depending on the type of test) in ≥3 neuropsychological tests. Patients with cognitive impairment had significantly higher mean diffusivity, radial diffusivity, and axial diffusivity values in the bilateral frontoparietal regions. In patients with cognitive impairment, mean diffusivity, radial diffusivity, and axial diffusivity showed correlations with various neuropsychological test scores. Executive function correlated with DTI measures of the frontal white matter, cingulum, inferior superior longitudinal and uncinate fasciculi, anterior thalamic radiations, and posterior lobe of the cerebellum. Visuospatial function correlated with the right parieto-occipital lobe, whereas visual-verbal memories correlated with the anterior thalamic radiations, inferior longitudinal and uncinate fasciculi, and the posterior lobe of the cerebellum. No significant correlations were found between fractional anisotropy and any of the neuropsychological test scores. CONCLUSIONS: The present study demonstrates a correlation between neuropsychological test scores and DTI measures, suggesting a neuroanatomic basis for cognitive impairment seen in patients with essential tremor. ABBREVIATIONS: ET essential tremor ETCI ET with cognitive impairment ETNCI ET without cognitive impairment HC healthy controls TBSS tract-based spatial statistics

Journal

American Journal of NeuroradiologyAmerican Journal of Neuroradiology

Published: Mar 1, 2015

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