Abstract Details

Title Impaired Oculomotor Control and Videonystagmogram Findings in a Case of Rhombencephalosynapsis

Topic Neuro-ophthalmology/Neuro-otology

Presentation(s) P02 - (-)

Poster/Presentation
Number 263

Objective

Background BACKGROUND: Rhombencephalosynapsis is a rare congenital abnormality characterized by dorsal fusion of the cerebellar hemispheres, fusion of dentate nuclei and superior cerebellar peduncles. Clinical presentation of rhombencephalosynapsis is very variable. Documentation and description of oculomotor findings in literature is sparse. There has been no report of video/electronystagmogram findings.

Design/Methods DESIGN/METHODS: Clinical examination, neuroradiological and neurophysiological oculomotor testing was conducted on our patient.

Results RESULTS: We report the case of a 36 year old right handed male patient who presented after head trauma due to an assault. Examination showed scanning dysarthria, saccadic eye movements, spontaneous and gaze evoked nystagmus, dysmetria and ataxia in upper and lower extremities and broad based ataxic gait with tendency to fall to either side. MRI Brain showed dorsal fusion of cerebellar folia, hypoplastic vermis and mild ventriculomegaly without significant supratentorial abnormalities consistent with mild partial rhombencephalosynapsis. Video nystagmogram showed markedly impaired static gaze holding with constant pendular cyclorotation with intrusive saccades. Nystagmus in the direction of lateralization and intrusive saccades were noted on horizontal and vertical gaze holdings. Large saccades and constant pendular horizontal shifting were noted with lateral head and body positions. Dynamic gaze holding was also markedly impaired with prolonged horizontal and downward latencies of saccades. Pursuit was also saccadic, disorganized and hypometric.

Conclusions CONCLUSIONS: Saccadic intrusions and pendular cyclorotation were the primary oculomotor abnormalities in our patient with hypoplasia of the cerebellar vermis. When combined with other observations in the patient, those ocular findings may enrich our understanding of cerebellar functions and can be helpful with clinical diagnosis.

Authors/Disclosures
Lakshmi Shankar, MD (Work) PRESENTER	Dr. Shankar has nothing to disclose.
Hongyan Li, MD, PhD, FAAN (University of Toledo Coll of Med & Life Sci - Dept of Neurology)	Dr. Li has nothing to disclose.
Frederick J. Derosier, DO (Covance, Inc)	No disclosure on file

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