Diagnoses behind patients with hard-to-classify tremor and normal DaT-SPECT: a clinical follow up study.

Manuel Menã©Ndez-Gonzã¡Lez,Francisco Tavares,Josã© M Salas-Pacheco,Nahla Zeidan,Oscar Arias-Carriã³N

doi:10.3389/fnagi.2014.00056

Abstract

The [123I]ioflupane—a dopamine transporter radioligand—SPECT (DaT-SPECT) has proven to be useful in the differential diagnosis of tremor. Here, we investigate the diagnoses behind patients with hard-to-classify tremor and normal DaT-SPECT. Therefore, 30 patients with tremor and normal DaT-SPECT were followed up for 2 years. In 18 cases we were able to make a diagnosis. The residual 12 patients underwent a second DaT-SPECT, were then followed for additional 12 months and thereafter the diagnosis was reconsidered again. The final diagnoses included cases of essential tremor, dystonic tremor, multisystem atrophy, vascular parkinsonism, progressive supranuclear palsy, corticobasal degeneration, fragile X–associated tremor ataxia syndrome, psychogenic parkinsonism, iatrogenic parkinsonism and Parkinson's disease. However, for 6 patients the diagnosis remained uncertain. Larger series are needed to better establish the relative frequency of the different conditions behind these cases.

Highlights

IntroductionRhythmic, oscillatory movement of a body part
Tremor is an involuntary, rhythmic, oscillatory movement of a body part
The acronym SWEDDs (Schneider et al, 2007), relatively recent in usage, arose from the clinical trial literature for Parkinson’s disease, in which patients were imaged with 18F-dopa PET or DaT-SPECT in order to monitor disease progression, revealing that a substantial proportion of clinically diagnosed cases of Parkinson’s disease had normal SCANS (4–15%) and were designated as SWEDDs (Schneider et al, 2007; Bajaj et al, 2012)

Summary

Introduction

Rhythmic, oscillatory movement of a body part. It is the most common movement disorder encountered in clinical practice. There is no diagnostic standard to distinguish among common types of tremor, which can make the evaluation challenging. History and physical examination can provide a great deal of certainty in diagnosis. Some cases showing more than one type of tremor or associating other signs and symptoms are specially difficult. Establishing the underlying cause is important because prognosis and specific treatment plans vary considerably

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Conclusion