Eye movement abnormalities in essential tremor.
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.
Department of Neurology, The John Paul II Hospital, Krakow, Poland.
Magdalena
M
Wójcik-Pędziwiatr
Department of Neurology, Medical University of Silesia, Katowice, Poland.
Klaudia
K
Plinta
Department of Neurology, Central Clinical Hospital of Medical Academy, Katowice, Poland.
Agnieszka
A
Krzak-Kubica
Department of Otolaryngology, Jagiellonian University Medical College, Krakow, Poland.
Katarzyna
K
Zajdel
Laboratory of Psychophysiology, Nencki Institute of Experimental Biology, Polish Academy of Science, Warsaw, Poland.
Marcel
M
Falkiewicz
Institute of Biocybernotechnic and Biomedical Engineering, Polish Academy of Science, Poznan, Poland.
Jacek
J
Dylak
Institute of Biocybernotechnic and Biomedical Engineering, Polish Academy of Science, Poznan, Poland.
Jan
J
Ober
Department of Neurology, Jagiellonian University Medical College, Krakow, Poland.
Andrzej
A
Szczudlik
Department of Neurology, Medical University of Silesia, Katowice, Poland.
Monika
M
Rudzińska
electrooculography; saccades; smooth pursuit