Disorders of Balance - Pathophysiology
Vertigo - Subjective sensation of movement
- will occur where there is a mismatch of sensory input, i.e. between vestibular + visual data. e.g after acute labyrinthitis with loss of function of 1 perpheral vestibular system. The vestibular data is suggestive of rotation and the eyes are therefore moved via the vestibulo-ocular reflex causing a sensation of the visual environment moving.Nystagmus - Involuntary eye movements due to a variety of causes:-
ocular
vestibular
neurological
congenital
hysterical Vestibular nystagmus - is usually horizontal or rotational and results from an ‘imbalance’ between the paired peripheral vestibular systems causing inappropriate eye movements.
There are 2 phases:-
slow phase – as the eyes deviate to one side.
fast phase – is the corrective movement, this results in beating movements of the eyes.
Disorders of balance occur when there is either a mismatch of sensory input (due to malfunction of 1 system relative to the others) or inadequate sensory or central function