![]() ![]() Clinical eye movement examination revealed frequent but irregular involuntary bursts of large to‐and‐fro horizontal saccades, responsible for oscillopsia. Cranial nerve examination was normal and deep tendon reflexes were all present. There was no motor or sensory deficit, no tremor and no limb ataxia. ![]() On neurological admission, the patient was able to stand but showed a clear truncal ataxia with a tendency to lean to the right. No previous symptoms of febrile infectious disease were reported. In order to account for this systematic directional bias, we propose that dysfunction of vermal pause neurons may be involved in the pathophysiology of ocular flutter, as experimental data have shown that these cells exhibit a marked directional selectivity.Ī 35‐year‐old man with no previous medical history experienced a rapid onset of dizziness, motion induced nausea and blurred vision, 3 weeks after returning from Africa. The most striking feature was that saccadic oscillations systematically started with a rightward saccade, a characteristic that cannot be explained by current models. Here, we report the case of a patient with an atypical ocular flutter not previously described in the literature. 4 More recently, instability in positive feedback loops involving EBN and IBN has been hypothesised as the critical factor responsible for saccadic oscillations, as may be observed in normal subjects. Earlier hypotheses ascribed saccadic oscillations to impaired OPN function. 2, 3 Its physiopathology remains unclear although it is currently accepted that it probably results from a dysfunction of brainstem oculomotor structures involved in saccade generation: excitatory burst neurons (EBN), inhibitory burst neurons (IBN) and omnipause neurons (OPN) that keep EBN and IBN silent, except immediately before and during saccade execution. 1 It is generally superimposed on normal oculomotor behaviour and its occurrence may be favoured by various events, such as blinks, the triggering of normal saccades or optokinetic stimulation. Ocular flutter is an abnormal eye movement consisting of repetitive, irregular, involuntary bursts of horizontal saccades without an intersaccadic interval. ![]()
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