Selective impairment of the rapid eye movements in myotonic dystrophy

Sung-Hee Kim; Jin-Sung Park

doi:10.14253/acn.2019.21.2.94

Journal List > Ann Clin Neurophysiol > v.21(2) > 1130242

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Kim and Park: Selective impairment of the rapid eye movements in myotonic dystrophy

Case Report

Ann Clin Neurophysiol 2017;21(2):94-97.

Published online: 5 January 2017

DOI: https://doi.org/10.14253/acn.2019.21.2.94

Selective impairment of the rapid eye movements in myotonic dystrophy

Sung-Hee Kim

, Jin-Sung Park

Department of Neurology, Kyungpook National University Chilgok Hospital, School of Medicine, Kyungpook National University, Daegu, Korea

Correspondence to Sung-Hee Kim Department of Neurology, Kyungpook National University Chilgok Hospital, School of Medicine, Kyungpook National University, 807 Hoguk-ro, Buk-gu, Daegu 41404, Korea Tel: +82-53-200-2168 Fax: +82-53-200-2029 E-mail: lossheaven9@gmail.com

Received 10 August 201827 September 2018 Accepted 26 October 2018

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

초록

The patients with myotonic dystrophy (MD) show ocular motor abnormalities including stra-bismus, vergence deficits, and inaccurate or slow saccades. Two theories have been proposed to explain the oculomotor deficits in MD. The central theory attributes the defects of eye movements of MD to the involvement of the central nervous system while the muscular theory attributes to dystrophic changes of the extraocular muscles. A 58-year-old woman with MD showed selective slowing of horizontal saccades and reduced peak velocities for both horizontal canals in head impulse tests, while smooth-pursuit eye movements and vertical head impulse responses were normal. This case suggests that the extraocular muscles-as a final common pathway of the voluntary saccade and reflexive vestibular eye movements-may better explain the defective rapid eye movements observed in MD.

Keywords: Head impulse test, Myotonic dystrophy, Saccades

REFERENCES

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Fig. 1.

A 58-year-old woman with myotonic dystrophy showed slowing and hypometria of horizontal saccades (A). The amplitudes and velocities of the vertical saccades were intact, although anticipatory eye movements were frequently observed (B). Smooth pursuit was normal in both horizontal directions (C) and in the upward direction (D). Video head impulse tests revealed decreased peak velocities for bilateral horizontal canals without catch-up saccades, but pre-served responses for the vertical canals (E). Upward deflection indicated rightward eye motion in the horizontal plane and upward eye motion in the vertical plane. S, seconds; HC, horizontal canal; AC, anterior canal; PC, posterior canal.

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