Sensory Alterations in Patients with Isolated Idiopathic Dystonia: An Exploratory Quantitative Sensory Testing Analysis.

Lejla Paracka,Mahmoud Abdallat,Florian Wegner,Christian Blahak,Assel Saryyeva,Matthias Karst,Dirk Dressler,Joachim K Krauss

doi:10.3389/fneur.2017.00553

Abstract

Abnormalities in the somatosensory system are increasingly being recognized in patients with dystonia. The aim of this study was to investigate whether sensory abnormalities are confined to the dystonic body segments or whether there is a wider involvement in patients with idiopathic dystonia. For this purpose, we recruited 20 patients, 8 had generalized, 5 had segmental dystonia with upper extremity involvement, and 7 had cervical dystonia. In total, there were 13 patients with upper extremity involvement. We used Quantitative Sensory Testing (QST) at the back of the hand in all patients and at the shoulder in patients with cervical dystonia. The main finding on the hand QST was impaired cold detection threshold (CDT), dynamic mechanical allodynia (DMA), and thermal sensory limen (TSL). The alterations were present on both hands, but more pronounced on the side more affected with dystonia. Patients with cervical dystonia showed a reduced CDT and hot detection threshold (HDT), enhanced TSL and DMA at the back of the hand, whereas the shoulder QST only revealed increased cold pain threshold and DMA. In summary, QST clearly shows distinct sensory abnormalities in patients with idiopathic dystonia, which may also manifest in body regions without evident dystonia. Further studies with larger groups of dystonia patients are needed to prove the consistency of these findings.

Highlights

The dystonias are a heterogenous group of movement disorders, which are defined by abnormal movements or postures [1, 2]
Patients with cervical dystonia were excluded in order to analyze more homogenously the relation of dystonia and sensory function
Our study shows that Quantitative Sensory Testing (QST) may detect subtle sensory abnormalities in patients with dystonia in absence of overt sensory deficits

Summary

Introduction

The dystonias are a heterogenous group of movement disorders, which are defined by abnormal movements or postures [1, 2]. According to the modern definition, dystonia represents a movement disorder, which is characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive movements, postures, or both. Idiopathic and inherited dystonia has been regarded as a disorder of basal ganglia activity and associated circuits. There is limited evidence of involvement of sensory systems in the pathophysiology of dystonia. Both imaging and electrophysiological studies have revealed abnormalities in sensorimotor networks [4, 5] and in cerebello-thalamo-cortical pathways [6, 7]

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