Isolated vocal tremor as a focal phenotype of essential tremor: a retrospective case review.

Amar Patel,Steven J Frucht

doi:10.1186/s40734-015-0016-5

Amar Patel, Steven J Frucht

Open Access

https://doi.org/10.1186/s40734-015-0016-5

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Abstract

BackgroundEssential tremor (ET) is a common condition associated with significant physical and psychosocial disability. “Classic” ET is a clinical syndrome of action tremor in the upper limbs and less commonly the head, jaw, voice, trunk, or lower limbs. Current diagnostic criteria for ET exclude isolated vocal tremor (IVT). Failure to recognize IVT as a form of ET may contribute to misdiagnosis and missed opportunities for treatment.MethodsWe conducted a retrospective review of cases referred for voice disturbance. Patients with a primary diagnosis of vocal tremor were included while those with a diagnosis of spasmodic dysphonia where excluded.Results19 cases of vocal tremor were identified, of which 17 patients (89%) were female. The average age of vocal symptom onset was 64 (SD 8.0) and patients had been symptomatic an average of 6 years (SD 4) at their initial visit. 8 patients had IVT while 11 also had evidence of subtle head or limb tremor. 8 patients (42%) had a family history of ET, with vocal tremor specifically identified in 5 of those cases (26%). 11 patients (58%) noted transient tremor improvement after alcohol consumption. Primidone and propranolol were the most common medications prescribed to these patients prior to consultation. 7 patients were given a trial of 1 gm of sodium oxybate in the office as part of a clinical trial, with at least mild improvement in vocal tremor noted by qualitative assessment.ConclusionsET may present as vocal tremor with little or no associated limb tremor. It may be a more common manifestation of ET in women. A family history of tremor and improvement in tremor after consuming alcohol can often be elicited on history. We propose that IVT may be part of the spectrum of ET.Electronic supplementary materialThe online version of this article (doi:10.1186/s40734-015-0016-5) contains supplementary material, which is available to authorized users.

Highlights

Essential tremor (ET) is a common condition associated with significant physical and psychosocial disability
E.g. dystonia, must be excluded, and traditionally vocal tremor is recognized as a feature of ET in anywhere from 10 to 25% of cases, isolated vocal tremor (IVT), defined as tremor of the voice in the absence of other observable tremor, does not meet current criteria for ET [7]
We propose that the phenomenologic characteristics of isolated vocal tremor (IVT) are consistent with its inclusion as a focal form of ET; and where both vocal and limb

Summary

Introduction

Essential tremor (ET) is a common condition associated with significant physical and psychosocial disability. ET has been defined by the Movement Disorder Society Consensus Statement on Tremor as a “bilateral, largely symmetric postural or kinetic tremor involving hands and forearms that is visible and persistent” [5]. These criteria were based on Tremor Investigation Group guidelines which included duration of illness as a major criterion [6]. E.g. dystonia, must be excluded, and traditionally vocal tremor is recognized as a feature of ET in anywhere from 10 to 25% of cases, isolated vocal tremor (IVT), defined as tremor of the voice in the absence of other observable tremor, does not meet current criteria for ET [7]. Voice tremor has classically been considered a secondary feature of ET which does not occur without upper limb tremor

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