Abstract Details

Title Pendular Hemi–See-Saw Nystagmus With Oculopalatal Tremor: Case Report and Systematic Review

Topic Neuro-ophthalmology/Neuro-otology

Presentation(s) P11 - Poster Session 11 (11:45 AM-12:45 PM)

Poster/Presentation
Number 17-008

Objective

To synthesize the evidence on HSSN and present a case with oculopalatal tremor (OPT)

Background

Hemi–see-saw nystagmus (HSSN) is an uncommon subtype, characterized by elevation and intorsion of one eye with contralateral depression and extorsion, typically in a jerk pattern. It is associated with unilateral lesions of the interstitial nucleus of Cajal and the medial longitudinal fasciculus, structures involved in the ocular tilt reaction. Although its association with OPT has been described, it is rare

Design/Methods We performed a systematic review of seven databases on HSSN, extracting data on demographics, etiology, lesion location, oculomotor findings, nystagmus pattern, outcomes, and additionally present a representative case

Results A systematic review of seven databases identified 14 reports including 35 cases. Thirteen provided complete data, with a mean age of 42.1 ± 19.7 years (range 18–69) and 53.8% male. The main etiology was ischemic stroke (53.8%), followed by AVM, AOA2, Joubert syndrome, Chiari I malformation, and cavernous malformation (7.7%). Lesions most frequently involved the bulbar/medullary region (30.8%) and mesencephalic tegmentum (15.4%). Jerk nystagmus was predominant (97.1%), and internuclear ophthalmoplegia was the most common supranuclear abnormality (65.7%). Four patients had an ocular tilt reaction, and among five with outcome data, two achieved complete resolution. Only one case of pendular HSSN with OPT has been previously reported. We describe a 30-year-old man with a pontine AVM presenting with pendular HSSN, eight-and-a-half syndrome, gaze-evoked nystagmus, ocular tilt reaction, incomplete Horner syndrome, and palatal tremor, consistent with OPT

Conclusions HSSN is an uncommon nystagmus, most often vascular and with frequent lower brainstem involvement. While HSSN usually presents as jerk, co-occurrence with OPT can shift the waveform to pendular, likely reflecting maladaptive brainstem–cerebellar oscillatory mechanisms. Larger, anatomically precise series are needed to refine structure–function correlations and prognosis

Authors/Disclosures
Fiorella E. Rivas Sarmiento, Dra PRESENTER	Dr. Rivas Sarmiento has nothing to disclose.
Jesus Daniel Gutierrez Arratia, MD	Dr. Gutierrez Arratia has nothing to disclose.
Christoper A. Alarcon Ruiz, MD (Instituto Nacional de Ciencias Neurológicas)	Dr. Alarcon Ruiz has received research support from Universidad Científica del Sur.
Tony A. Torres Inuma	Dr. Torres Inuma has nothing to disclose.
Guido E. Alban Zapata	Dr. Alban Zapata has nothing to disclose.
Justiniano O. Zea Quispe, Sr., MD (Perú)	No disclosure on file

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