[Pathologic nystagmus and related phenomena. A review]

Area of Science:

• Ophthalmology
• Neurology
• Vestibular Science

Context:

• Pathological nystagmus encompasses a range of involuntary eye movements.
• Differentiating between peripheral and central vestibular nystagmus is crucial for diagnosis.
• Nystagmus can be spontaneous, positional, or gaze-evoked, each with distinct characteristics.

Purpose:

• To categorize and describe the various types of pathological nystagmus.
• To highlight key differentiating features, such as fixation inhibition and waveform characteristics.
• To provide an overview of related ocular motility disorders.

Summary:

• Peripheral vestibular nystagmus, often rotatory, is typically inhibited by fixation, unlike central nystagmus.
• Spontaneous congenital nystagmus is distinguished by its duration, waveforms, and frequency.
• Positional nystagmus includes static and paroxysmal types, with benign paroxysmal positional nystagmus being common.
• Gaze-evoked nystagmus can be symmetrical, often drug-induced, and includes dissociated, rebound, and gaze-paretic forms.
• Associated phenomena include ocular flutter, opsoclonus, and ocular myoclonus.

Impact:

• Facilitates accurate diagnosis and classification of nystagmus subtypes.
• Informs clinical decision-making for patients with involuntary eye movements.
• Enhances understanding of the complex mechanisms underlying vestibular and ocular motor disorders.