White matter microstructural changes are related to cognitive dysfunction in essential tremor

Abstract

Diffusion tensor imaging (DTI) studies have detected white matter microstructural changes in essential tremor (ET). However, it is still unclear whether these changes are related to cognitive deficits, which have been described in ET patients. DTI-derived fractional anisotropy, mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity measures were compared between 23 ET patients and 23 age-, gender-, and education-matched healthy individuals, using whole-brain tract-based spatial statistics. Correlations of white matter changes with scores obtained from a detailed neuropsychological assessment were subsequently examined. ET patients demonstrated increases in MD in the bilateral posterior corona radiata, bilateral superior longitudinal fasciculus, bilateral fornix (cres)/stria terminalis, genu and splenium of the corpus callosum, bilateral anterior and posterior limbs of internal capsule, bilateral retrolenticular region part of internal capsule, and left posterior thalamic radiation. Except for the genu of the corpus callosum, an increase in AD values was also found in these same tracts. Furthermore, increased MD and AD values in different white matter areas was negatively correlated with performance on language and verbal memory and positively with visuospatial ability. These correlations suggest that white matter changes might be involved in the pathogenesis of cognitive deficits in ET.

Microstructural abnormalities in callosal fibers and their relationship with cognitive function in schizophrenia: A tract‐specific analysis study

“…To our knowledge, there is no study reported relationship of AD value with cognitive function in schizophrenia. The studies on patients with essential tremor showed positive correlation between the AD value and cognitive function (Julian et al, ; Bhalsing et al, ). Same as these previous studies on essential tremor, our SZ group showed significant relationship of increased AD with better attention scores, while AD value in the SZ group was significantly increased compared to the HC group.…”

Microstructural Alterations in Asymptomatic and Symptomatic Patients with Spinocerebellar Ataxia Type 3: A Tract-Based Spatial Statistics Study

“…The posterior thalamic radiation is also related to cognition in some way. Previous researchers have revealed that posterior thalamic radiation damage was related to cognition in essential tremor ( 54 ) and may also be associated with intellectual performance ( 55 ).…”

Mind the gaps: What we don't know about cognitive impairment in essential tremor

“…Though it is not impossible for memory deficits (or language and spatial deficits) to reflect the distal effects of cerebellar compromise on hippocampal, temporal and parietal regions respectively, such cognitive deficits might be explained more parsimoniously by direct deterioration of these regions, such as that which may occur early in the course of Alzheimer's disease [44][45][46]. Consistent with a neuropathological model of cognitive impairment in ET that extends beyond the cerebellum, diffusion tensor imaging (DTI) studies have shown that the integrity of white matter microstructure is compromised throughout the brain [47], resting state imaging has revealed altered functional connectivity throughout the cerebral cortex [48] [49], and structural MRI has shown smaller cerebral cortical gray matter volume [50]. In at least a subset of ET cases, therefore, there appears to be a neurodegenerative process occurring outside of the cerebellum at a higher rate than that which is seen in age matched controls [47,51].…”