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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


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

  • Authors: Félix Bermejo-Pareja, MD, PhD
  • CME Released: 4/12/2011
  • Valid for credit through: 4/12/2012
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Target Audience and Goal Statement

This activity is intended for primary care clinicians, family practitioners, and other health professionals caring for patients with benign essential tremor.

The goal of this activity is to review the evidence that essential tremor may be a slowly progressive neurodegenerative disorder.

Upon completion of this activity, participants will be able to:

  1. Describe cognitive and mood abnormalities in patients with essential tremor on the basis of review findings
  2. Describe evidence for cerebellar and other pathology in patients with essential tremor on the basis of review findings
  3. 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


    Disclosure: Félix Bermejo-Pareja, MD, PhD, has disclosed no relevant financial relationships.


  • Heather Wood

    Chief Editor, Nature Reviews Neurology


    Disclosure: Heather Wood has disclosed no relevant financial relationships.

CME Author(s)

  • Laurie Barclay, MD

    Freelance writer and reviewer, Medscape, LLC


    Disclosure: Laurie Barclay, MD, has disclosed no relevant financial relationships.

CME Reviewer(s)

  • Nafeez Zawahir, MD

    CME Clinical Director, Medscape, LLC


    Disclosure: Nafeez Zawahir, MD, has disclosed no relevant financial relationships.

  • Sarah Fleischman

    CME Program Manager, Medscape, LLC


    Disclosure: Sarah Fleischman has disclosed no relevant financial relationships.

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



At the end of the 20th century, essential tremor was considered to be a monosymptomatic condition that was distinct from other disorders associated with tremor, such as dystonia, PD and myoclonus.[13,57] This classic concept of essential tremor maintained that the condition was not caused by structural changes within the CNS.[10] In the past decade, however, this concept has been challenged. Studies indicate that many patients with essential tremor also experience subtle neurological deficits that are considered to result from cerebellar dysfunction, such as tandem gait ataxia, bradykinesia, and dysfunctional hand-eye coordination and ocular movements, among others.

Within the past decade, patients with essential tremor have also been shown to experience cognitive impairments and mood disorders (mainly depression). The cognitive deficits are typically mild, and are a common feature of this condition. The observations that both essential tremor and the cognitive deficits associated with this disorder are typically progressive, patients with this condition have an increased risk of dementia,[36,37] and the majority of essential tremor cases have evidence of cerebellar pathology has changed the concept of essential tremor completely. In fact, it might be more appropriate to consider essential tremor to be a neurodegenerative disorder.

Most cases of essential tremor probably occur as a result of cerebellar pathology (Purkinje cell loss and degeneration with evidence of 'torpedos' and gliosis). In a subgroup of patients, however, the condition might be caused by brainstem pathology, including locus coeruleus nuclei cell loss associated with Lewy body inclusions.[44] Neuroimaging studies have shown that cerebellar dysfunction is evident in some patients with essential tremor. In such situations, the mild cognitive and mood disorders could be manifestations of subclinical CCAS, and could result from damage to neural networks that require coordinated activity in the cerebellum, the sensorimotor cerebral cortex, and the dorsolateral prefrontal, parietal-temporal and limbic cortices.[109-111] The knowledge acquired during the past decade needs further evidence from clinical and basic neuroscience studies before essential tremor can be classified as a neurodegenerative cerebellar disorder.