nystagmus
Pronunciation: ni-STAG-mus
Involuntary rhythmic eye movements that can indicate vestibular, cerebellar, or brainstem dysfunction.
Full Definition
Nystagmus is a neurological sign characterized by involuntary, rhythmic oscillations of the eyes that can be horizontal, vertical, or rotatory in direction. It results from dysfunction in the neural pathways that control eye movement and can indicate problems with the vestibular system, cerebellum, brainstem, or central nervous system. Nystagmus is classified as physiological (normal response to certain stimuli), pathological (indicating disease), congenital, or acquired. In clinical examination, the direction, amplitude, frequency, and whether it's present in primary gaze or only with certain eye movements provides important diagnostic information about the underlying neurological condition.
Usage
Usage note: Specify direction (horizontal/vertical/rotatory) and whether present in primary gaze or only with eye movement.
In Context
- "Horizontal nystagmus was observed on lateral gaze, suggesting a peripheral vestibular lesion." — dizziness evaluation
- "The patient's downbeat nystagmus in primary position indicated a likely cervicomedullary junction abnormality." — neuro-ophthalmology consultation