What is vestibology
Vestibology is a branch of otolaryngology specialisation, the medical field which deals with the diagnosis, therapy and rehabilitation of disorders related to balance and equilibrioception. The vestibular system is a complex sensory system of inputs and outputs, functionally linked to positive and negative feedback mechanisms between labyrinth, brain, cerebral regions, cerebellum, proprioception, and visual system.
Therefore, the vestibular apparatus is a set of functional organs supported by a system and various subsystems, which starting from the inner ear, provide information on the position of the head in space and its movements, allows the maintenance of the gaze within the environment, and retains posture, all of which are fundamental for spatial orientation.
In summary, this entire anatomical-physiological mechanism determines the perception of the body in space, and therefore the condition of equilibrium.
The disorders pertaining to vestibology are vertigo, postural instability (dizziness), and often also tinnitus, hearing loss, and migraines.
The reception and development of movement, and therefore of balance, is regulated by the labyrinth receptors and by the functionality of the joint receptors of the general proprioception through sending and processing of inputs to the vestibular nuclei of the brainstem.
For this reason, the development of physical activity focuses its manifestation through 3 basic functions:
- antigravity posture
The fundamental condition of the three functions is balance, given by active responses of the vestibular functionality, without which the other two functions cannot have correct responses and implementations. For example, it is possible to have walking deficiencies without compromising balance, however the contrary is absolutely impossible.
of the vestibular system
The labyrinth can be divided into bony and membranous, with the former being moulded onto the latter. It consists of:
- Semicircular canals (lateral, posterior, superior or anterior)
- Otolithic organs (utricle and saccule and related maculae)
VOR, VRS, OPK
These are the main reflexes devoted to the correct maintenance of balance.
The vestibular system is essentially based on two fundamental reflexes:
- Vestibulo–ocular reflex (VOR)
- Vestibulo-spinal reflex (VSR)
VOR works by stabilising the optimal vision during the movements of the head so as to stabilise the gaze and allowing the distinction of the foveal vision.
VRS coordinates and stabilises the movement of the head with the body movements and helps the head and body to remain upright.
The semicircular canals are the sensors of the angular acceleration allowing the rotation of the head.
Otoliths are sensors of linear accelerations and detect:
- head movement
- position of the head in relation to the horizon
Nystagmus has a fundamental and basic role in evaluating the balance system. Indeed, it can be artificially defined as the centre of the world and of vestibular investigations. It is a reflex movement of the eyeballs whereby it is possible to distinguish a pendular nystagmus and a saccadic nystagmus in which a slow phase and a rapid phase are recognisable. Nystagmus is not necessarily pathological, as there are various physiological ones. It is connected to the function/dysfunction of the vestibulo–ocular reflex (VOR) which allows the maintenance of the ocular visual axis directed towards a specific point in the visual field during the movements (accelerations) of the head.