Inner ear disorders.

OBJECTIVES: To present a framework for the diagnosis and treatment of inner ear disorders, with an emphasis on problems common to neuro-rehabilitation.

INTRODUCTION: Disorders of the inner ear can cause hearing loss, tinnitus, vertigo and imbalance. Hearing loss can be conductive, sensorineural, or mixed; conductive hearing loss arises from the ear canal or middle ear, while sensorineural hearing loss arises from the inner ear or auditory nerve. Vertigo is a hallucination of motion, and is the cardinal symptom of vestibular system disease. It should be differentiated from other causes of dizziness: gait imbalance, disequilibrium, lightheadedness (pre-syncope). Vertigo can be caused by problems in the inner ear or central nervous system.

METHODS: The diagnosis of inner ear disorders begins with a targeted physical examination. The initial work-up of hearing loss is made by audiometry, and vertigo by electronystagmography (ENG). Supplemental tests and MRI are obtained when clinically indicated.

RESULTS: The clinical pattern and duration of vertigo are the most important clinical features in the diagnosis. Common inner ear causes of vertigo include: vestibular neuritis (sudden, unilateral vestibular loss), Meniere's disease (episodic vertigo), benign paroxysmal positional vertigo (BPPV), and bilateral vestibular loss. Common central nervous system causes of vertigo include: post concussion syndrome, cervical vertigo, vestibular migraine, cerebrovascular disease, and acoustic neuroma.

CONCLUSION: A basic knowledge of vestibular physiology, coupled with a understanding of common vestibular syndromes, will lead to correct diagnosis and treatment in most cases.