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

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

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.

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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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