Eye movement abnormalities in essential tremor

Abstract

Essential tremor (ET) is the most prevalent movement disorder, characterized mainly by an action tremor of the arms. Only a few studies published as yet have assessed oculomotor abnormalities in ET and their results are unequivocal. The aim of this study was to assess the oculomotor abnormalities in ET patients compared with the control group and to find the relationship between oculomotor abnormalities and clinical features of ET patients. We studied 50 ET patients and 42 matched by age and gender healthy controls. Saccadometer Advanced (Ober Consulting, Poland) was used to investigate reflexive, pace-induced and cued saccades and conventional electrooculography for evaluation of smooth pursuit and fixation. The severity of the tremor was assessed by the Clinical Rating Scale for Tremor. Significant differences between ET patients and controls were found for the incidence of reflexive saccades dysmetria and deficit of smooth pursuit. Reflexive saccades dysmetria was more frequent in patients in the second and third phase of ET compared to the first phase. The reflexive saccades latency increase was correlated with severity of the tremor. In conclusion, oculomotor abnormalities were significantly more common in ET patients than in healthy subjects. The most common oculomotor disturbances in ET were reflexive saccades dysmetria and slowing of smooth pursuit. The frequency of reflexive saccades dysmetria increased with progression of ET. The reflexive saccades latency increase was related to the severity of tremor.

Essential tremor: the most common form of cerebellar degeneration?

“…Of additional interest is that these oculomotor abnormalities were particularly evident among those ET patients who also exhibited intention tremor [76], which as noted above canonically has been viewed as a sign of cerebellar dysfunction. The presence of sub-clinical eye movement abnormalities in ET patients has been confirmed in several additional studies [77,78]. Second, several studies have revealed abnormalities in limb motor behavior in ET [79][80][81][82][83].…”

Essential tremor: diagnosis and management

“…A case-control study of 50 patients with essential tremor reported that the latency of reflexive saccades was associated with severity of tremor. Additionally, an increased incidence of dysmetria was seen during reflexive saccades in patients with more severe disease 57…”

Percepção Visual no Tremor Essencial: Uma Revisão Sistemática

“…Estudos que avaliaram o rastreamento ocular indicaram a possibilidade de existência de 1 início sacádico (Helmchen et al, 2003;Wójcik-Pędziwiatr et al, 2016). Observou-se também que a espessura foveal medida pela Tomografia de Coerência Óptica (OCT) pode ser um biomarcador promissor para TE e DdP (Satue et al, 2016;Sharifi et al, 2014).…”