Oculomotor, auditory, and vestibular responses in myotonic dystrophy
W. I. Verhagen, J. P. ter Bruggen and P. L. Huygen
Department of Neurology, Canisius-Wilhelmina Hospital Nijmegen, The Netherlands.
In 13 patients with myotonic dystrophy, oculomotor, auditory, and
vestibular tests were performed. All 13 patients showed one or more
abnormalities. There was a significant increase in the penetrance of the
separate abnormalities with age. Saccadic slowing was found in 10 patients,
in a severe form in three. Seven patients had a sensorineural high-tone
hearing loss (30 to 85 dB at 8 kHz), which was in excess of that expected
for their age, that could be attributed to myotonic dystrophy. Brain-stem
auditory evoked potentials showed a significant interwave delay of the I-V
interval (0.35 to 0.7 milliseconds). An abnormal vestibulo-ocular reflex
was found in six patients; three had vestibular hyperreflexia with
increased gain, and three had hyporeflexia with short time constants. This
study confirms that in myotonic dystrophy, sensory system involvement can
be found on both a peripheral and a central level.
