Table 1.

Cognitive Deficits Associated with Essential Tremor³⁴

Box 1.

Classic Concept of Essential Tremor

Box 2.

Essential Tremor: New Findings

Box 3.

Cognition in Patients with Essential Tremor

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CME

Essential Tremor -- A Neurodegenerative Disorder Associated With Cognitive Defects?

Authors: Félix Bermejo-Pareja, MD, PhD
CME Released: 4/12/2011
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Describe cognitive and mood abnormalities in patients with essential tremor on the basis of review findings
Describe evidence for cerebellar and other pathology in patients with essential tremor on the basis of review findings
Describe recommended diagnostic workup in patients with essential tremor on the basis of review findings

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Félix Bermejo-Pareja, MD, PhD

Department of Neurology, University Hospital "Doce de Octubre," Madrid, Spain

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Heather Wood

Chief Editor, Nature Reviews Neurology

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Freelance writer and reviewer, Medscape, LLC

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Sarah Fleischman

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Prevalence and Incidence

Essential tremor is a condition that affects individuals worldwide. In studies conducted in the latter half of the 20^th century, the prevalence of essential tremor in the Western world was documented to be 0.3-4.0% in individuals over 40 years of age (males and females were shown to be affected more or less equally), with an incidence of 23.7 per 100,000 people per year reported.^[1,6,51-53] Studies conducted in the past two decades, however, indicate that the prevalence and incidence of essential tremor in the elderly population could be substantially higher than the figures reported earlier. Studies in the elderly suggest that prevalence in these patients ranges between 3.9% and 14.0%. For example, in the Neurological Disorders in Central Spain (NEDICES) study, the prevalence of essential tremor was shown to be 4.8%, but in the oldest old (over 80 years) the prevalence increased to over 6%.^[54] The incidence of essential tremor in the NEDICES study was 6.2 (95% CI 4.4-7.2) per 1,000 person-years.^[55] A recent meta-analysis showed that the prevalence of essential tremor increased with age in all studies, and could be especially high (21.7%) in the very old (95 years and over).^[56] The age of onset of essential tremor is variable: it may begin in childhood in some individuals, but the majority of patients with this condition present with tremor in the 2^nd or 6^th decades of life.^[56] The Russian neurologist Lazar Minor speculated that patients with essential tremor had above-average intelligence, longevity and fecundity but these assertions were unsupported.^[49] The hypothesis that essential tremor is an exaggeration of physiological tremor,^[2] or an attenuated form of olivopontocerebellar atrophy^[49] or PD,^[57] also seems speculative.

50-70% of essential tremor cases are estimated to be genetic in origin, and the genetic mutations in these cases are predicted to be transmitted in an autosomal dominant manner and to have variable penetrance.^[1-6]

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Diagnosis

CME Information

References

Table 1.

Box 1.

Box 2.

Box 3.

CME

Essential Tremor -- A Neurodegenerative Disorder Associated With Cognitive Defects?

Target Audience and Goal Statement

Disclosures

Author(s)

Félix Bermejo-Pareja, MD, PhD

Editor(s)

Heather Wood

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Laurie Barclay, MD

CME Reviewer(s)

Nafeez Zawahir, MD

Sarah Fleischman

Accreditation Statements

For Physicians

Instructions for Participation and Credit

Essential Tremor -- A Neurodegenerative Disorder Associated With Cognitive Defects?: Prevalence and Incidence

Prevalence and Incidence

Table of Contents

Table 1.

Box 1.

Box 2.

Box 3.

References

Faculty and Disclosures

Author(s)

Félix Bermejo-Pareja, MD, PhD

Editor(s)

Heather Wood

CME Author(s)

Laurie Barclay, MD

CME Reviewer(s)

Nafeez Zawahir, MD

Sarah Fleischman

CME

Essential Tremor -- A Neurodegenerative Disorder Associated With Cognitive Defects?

Target Audience and Goal Statement

Disclosures

Author(s)

Félix Bermejo-Pareja, MD, PhD

Editor(s)

Heather Wood

CME Author(s)

Laurie Barclay, MD

CME Reviewer(s)

Nafeez Zawahir, MD

Sarah Fleischman

Accreditation Statements

For Physicians

Instructions for Participation and Credit

Essential Tremor -- A Neurodegenerative Disorder Associated With Cognitive Defects?: Prevalence and Incidence

Prevalence and Incidence

Table of Contents