Biomarkers demonstrate increased consumption, but not abuse, of ethanol in essential tremor

Essential Tremor - A Cerebellar Driven Disorder?

Abnormal tremors are the most common of all movement disorders. In this review we focus on the role of the cerebellum in Essential Tremor, a highly debilitating but poorly treated movement disorder. We propose a variety of mechanisms driving abnormal burst firing of deep cerebellar nuclei neurons as a key initiator of tremorgenesis in Essential Tremor. Targetting these mechanisms may generate more effective treatments for Essential Tremor.

Effects of chronic alcohol consumption on long-term outcomes of thalamic deep brain stimulation for essential tremor

The prevalence of essential tremor (ET) is about 4% above 40years of age. Chronic alcohol consumption is present in around 20% of patients with ET. Our objective was to identify whether chronic alcohol consumption was associated with a negative effect on tremor outcome after thalamic deep brain stimulation (DBS) in ET patients. We conducted a retrospective chart review, from January 2005 to December 2012, from which 23 patients who had ventral intermediate nucleus (Vim)-DBS surgery for ET were identified. Seven patients had a positive history of chronic alcohol consumption. We defined as chronic alcohol users those patients with a habit of drinking alcohol every day in order to suppress tremor. In the overall group of 23 patients, there was a reduction in the median tremor score from 8 pre-operatively, to 1 post-operatively (p<0.0001). The alcohol consumers group experienced a reduction in the median tremor score from 6 pre-operatively to 0 post-operatively (p=0.03). The non-alcohol consumers group had a reduction in the median tremor score from 8 pre-operatively to 1.7 post-operatively (p<0.0001). Both groups of patients experienced significant benefit from thalamic DBS. A larger study may reveal statistically significant differences between subgroups.

The potential of LINGO-1 as a therapeutic target for essential tremor

INTRODUCTION

LINGO-1 is a negative regulator of neuronal survival, oligodendrocyte differentiation and axonal outgrowth and regeneration, because it interacts with diverse growth factor receptors blocking or inhibiting their action. Consistent findings obtained in vitro and in animal models suggest that anti-LINGO-1 therapy may be useful in neurodegenerative disorders such as multiple sclerosis (MS), Parkinson's disease or essential tremor (ET). Moreover, genetic and pathological evidence provide a robust link between LINGO-1 and ET.

AREAS COVERED

In this review, we present an overview of current knowledge on findings linking LINGO-1 and ET, with a special focus on genetic linkage, we include an overview of LINGO1 gene variations according to the 1000 genomes catalog, and we identify potential gene areas where common changes occur because, as well as the risk developing ET, LINGO1 genetic changes may influence the response to anti-LINGO-1 therapy.

EXPERT OPINION

The goal of anti-LINGO-1 therapy in neurodegenerative diseases is to ease the brakes of neuronal growth and recovery. An anti-LINGO-1 antibody is under clinical trials for MS patients. Before planning trials with ET patients, refinement on the genetic link between LINGO1 and ET, and a detailed genetic and phenotypic assessment of ET patients to be enrolled, should be carried out.

Semi-quantitative data on ethanol consumption in 354 ET cases and 370 controls

The notion that there is an association between essential tremor (ET) and higher ethanol consumption has crept into the literature; however, the data are limited and conflicted. A total of 354 ET cases and 370 matched controls were enrolled in a clinical-epidemiological study. Average current daily ethanol consumption was estimated using the Willett Semi-quantitative Food Frequency Questionnaire. The proportion of cases and controls who drank any ethanol was similar: 66.7% vs. 64.1%, p=0.46, as was the proportion who reported heavy ethanol consumption: 4.0% vs. 3.5%, p=0.74. The average daily ethanol intake was numerically higher in cases than controls (7.99 ± 12.39 [median=3.03] vs. 6.55 ± 10.62 [median=1.80] g), but this difference did not reach significance (p=0.15). Among cases, there was no correlation between average daily ethanol intake and tremor severity (r=0.008, p=0.88). These data, on more than 700 enrollees, do not support any sizable differences between ET cases and controls in terms of average daily ethanol consumption or ethanol overuse. The absence of a correlation in cases between ethanol consumption and tremor severity goes against the hypothesis that ET patients are self-medicating to a significant degree.