Clinical Evaluation of Patients with Vestibular Dysfunction

Abstract

Dizziness is a common reason for outpatient neurology consultation. Oftentimes, a complete workup by general practitioner, including MRI brain fails to reveal a cause. Some patients would have also undergone an ENT evaluation before approaching neurology for an answer. Such scenarios provide a challenge as well as opportunity for the neurologist to exercise their knowledge and clinical skills in arriving at a diagnosis. Conditions like 'Unspecified Vestibular Dysfunction' and 'Presbyvertigo' are often the underlying causes, which are either not recognized or misdiagnosed as BPPV, psychogenic or perceptive dizziness. This article's goal is to help understand vestibular system and diagnose vestibular dysfunction in clinical practice.

Figure 1

The Balance System. Balance as a function of vestibular system with visual and sensory inputs.

Figure 2

The real vestibular system. Impulses are carried from the horizontal semicircular canals and the otolith organs to the vestibular nuclei. Ascending and descending pathways that travel to various cranial nerve nuclei III, IV,VI are depicted here. Few fibers go directly to the cerebellum without synapsing in the vestibular nuclei. Ascending fibers travel through MLF to control ipsilateral and contralateral eye movements. Descending pathways travel to the neck and trunk through the vestibulocollic and vestibulospinal pathways to control neck and body positions to maintain balance.