Balanssinnet

Balanssinnet, or the vestibular sense, is the sensory system that provides information about head movement, head position relative to gravity, and spatial orientation. In many contexts, it is referred to as balanssinnet to denote the Swedish term for this sense.

Anatomy and physiology: The vestibular apparatus is located in the inner ear and comprises three semicircular canals that detect angular acceleration and two otolith organs—the utricle and saccule—that detect linear acceleration and head tilt. Hair cells transduce mechanical motion into neural signals carried by the vestibular nerve, part of cranial nerve VIII, to brainstem and cerebellum. The system works in concert with visual and proprioceptive inputs to form a coherent sense of balance and motion.

Functions: The vestibular system supports balance, posture, and spatial orientation. It also stabilizes gaze through the vestibulo-ocular reflex, ensuring clear vision during head movement. In daily activity, it helps coordinate movements and maintain equilibrium on varied surfaces and in dynamic tasks.

Development and plasticity: The vestibular sense develops in early life and can adapt throughout adulthood. Neuroplastic changes support compensation after unilateral or bilateral vestibular loss, especially with targeted rehabilitation that promotes recalibration of sensory inputs and motor responses.

Clinical aspects: Disorders of balanssinnet include conditions such as benign paroxysmal positional vertigo (BPPV), vestibular neuritis, labyrinthitis, Menière’s disease, and bilateral vestibulopathy. Diagnosis employs tests like caloric testing, rotary chair, video head impulse testing (vHIT), and vestibular-evoked myogenic potentials, along with clinical history and sometimes imaging.

Treatment and management: Management often centers on vestibular rehabilitation therapy (VRT) to promote adaptation and compensation. Specific maneuvers (for example, canalith repositioning for BPPV) and, when appropriate, medical or surgical interventions are used depending on the underlying condition.