Ocular Flutter Associated with a Thalamic Lesion

Seo, Man Wook

Abstract

Ocular flutter is a rare, horizontal eye movement disorder characterized by rapid saccadic oscillations. Previous reports have presented a relationship between ocular flutter syndrome and many conditions/diseases. However, it is surprising that there have been few reported cases in which there has been a clear anatomically localized lesion linked to ocular flutter. So the pathophysiological basis for ocular flutter syndrome is not understood yet. We have recently experienced a case of ocular flutter syndrome where the ocular flutter was associated with dysmetria, dysdiadochokinesia, kinetic predominant tremor, and ataxia. The prodromal symptoms, self-limited illness course and cerebrospinal fluid (CSF) pleocytosis of our case suggest an infectious aetiology for this syndrome. Although most of the sequelae of infectious diseases represent more diffuse involvement of the nervous system, the predominant cerebellar symptoms and signs associated with ocular flutter imply that the single responsible lesion of the present case might have been related to the cerebellum-associated neural circuits. Brain single photon emission computed tomography (SPECT) in the present case showed perfusion decrease in the left thalamus. The present case suggests that the cerebellar output circuit (dorsal vermis-fastigial nucleus-vestibular nucleus-thalamus-cortex) might be related to the occurrence of ocular flutter. The description of this case may improve the understanding of the pathological mechanisms of ocular flutter syndrome.