A Voxel-Based Magnetic Resonance Imaging Morphometric Study of Cerebral and Cerebellar Gray Matter in Patients Under 65 Years with Essential Tremor

Abstract

BackgroundThe aim of this study was to compare the morphological changes in cerebral and cerebellar gray matter in patients with essential tremor under 60-years-of-age, with age-matched and gender-matched normal healthy volunteer control subjects, using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM) analysis.Material/MethodsA retrospective, controlled, comparative clinical study included 17 patients with essential tremor, <60 years-of-age, and 17 age-matched and gender-matched healthy volunteer control subjects, recruited between June 2010–July 2012. MRI and VBM analysis were used to compare cerebral and cerebellar gray matter density between groups. The Washington Heights–Inwood Genetic Study of Essential Tremor (WHIGET) rating scale was used to assess tremor severity in the patient group. Clinical and demographic characteristics were recorded for all study participants.ResultsMRI and VBM analysis showed significant bilateral expansion of the cerebellum, occipital fusiform cortices, right inferior temporal gyrus, and precentral lobes in patients with essential tremor (P<0.005); reduction in gray matter was found in the left parietal lobe. The region of interest (ROI) analysis showed volume enlargement in the thalamus, midbrain, and the precuneus (P<0.005). No significant correlation between changes in gray matter and changes in clinical variables, including age, gender, tremor duration, the activity of daily living (ADL) scale, the mini-mental state examination (MMSE) scale, family history, and tremor severity were found.ConclusionsPredominantly cerebellar gray matter expansion in patients less than 60 years-of-age with essential tremor might be the result of compensation for the decline in cerebellar function.

Neuroimaging and neuropathological findings in essential tremor

“…55 showed different findings, with compensatory increase of the gray matter in the cerebellum and other brain areas, 18,19 rather than atrophy showed by older studies. 55 showed different findings, with compensatory increase of the gray matter in the cerebellum and other brain areas, 18,19 rather than atrophy showed by older studies.…”

“…It could be accepted that studies, where no cerebellar signs or other neurological deficits mentioned, have used only essential tremor patients, but whether their findings could be reliable is still questionable while they had not used the new diagnostic criteria and there is a strong risk of patients with different types of tremor may have been included. Most recent studies using the new classification for tremor and the new diagnostic criteria for essential tremor showed different findings, with compensatory increase of the gray matter in the cerebellum and other brain areas, 18,19 rather than atrophy showed by older studies. [10][11][12][13][14][15] Further studies which will consider the new classification of tremor and will rigorously apply the new diagnostic criteria for essential tremor and which will categorize patient based on both clinical phenotypes and the etiology needed in order to clarify the microscopic and macroscopic changes in essential tremor.…”

Voxel-based morphometry and task functional magnetic resonance imaging in essential tremor: evidence for a disrupted brain network

“…Moreover, Bhalsing et al detected GM volume reduction covering the anterior and posterior lobules of the cerebellum bilaterally in ET associated with cognitive impairment 18 . On the other hand, several studies did not show any differences in GM cerebral and cerebellar volumes between ET patients and HC 13,[19][20][21][22] , whereas others reported increased GM volumes of the bilateral cerebellum 23,24 and right occipital fusiform gyrus 24 in ET patients. Discrepancies among studies might be attributable to patient selection reflecting, among others, less stringent diagnostic criteria for ET in the past, as well as to different MRI field strengths and heterogeneous anatomical sequences acquired in the populations 11 .…”

Impaired integrity of commissural and association fibers in essential tremor patients: Evidence from a diffusion tensor imaging study

“…Neuroimaging studies also demonstrated structural changes in grey matter regions as frontal, temporal and occipital cortex [22,[30][31][32][33], insula, precuneus [22,31], basal ganglia, red nucleus, substantia nigra and thalamus [34]. Neurodegenerative nature of the disease and a number of accompanying non-motor symptoms suggest that this neurodegeneration may also spread to white matter.…”

“…As a result, reduced purkinje cell inhibitory output and impaired fiber connections between cerebellar cortex and dentate nucleus were observed [20,21]. Functional and structural neuroimaging studies identified the involvement of cerebellar pathways [16,22,[23][24][25][26][27][28][29].…”