Dizziness is not a disease it is one of the most common symptoms of vestibular dysfunction. There are mainly two types of vestibular dysfunction central and peripheral vestibular dysfunction. Signs of vestibular dysfunction are vertigo, nystagmus, visual instability on head movement, spinning, double vision, May or may not have hearing loss or tinnitus. Due to these problem the patient feel difficulty in movements and in other activities, asymmetrical posture in sitting or standing. patients who experience dizziness report a significant disability that reduces their quality of life.
Vestibular system is consist of two parts central vestibular system and peripheral vestibular system. Peripheral part is consist of three semi-circular canals and otolith organs. The three semi-circular canals horizontal, posterior and anterior respond to angular acceleration and are right angle to one another. Semi-circular canals are filled with endolymph. Which move freely within each canal in response to the direction of the angular head rotation. The saccule and utricle make up the otolith organ which respond to the linear acceleration and the static head tilt. Three main functions of the peripheral vestibular system is stabilize visual images during head movement, maintain postural stability during head movement and providing information about the environment. In the central vestibular system brainstem processes provide primary control of many vestibular reflex. Connection with the thalamus, vestibular cortex and reticular system enable the vestibular system to aware of arousal and conscious awareness of the body and discrimination between the self and environment.
In children, vestibular function plays an important role in postural and gross motor development control. Children with congenitally profound hearing loss suffer vestibular dysfunction in both ears, and loss of postural control. Maintaining and development of postural stability is a multisystem process it does not only depend on vestibular input. Maturational changes in proprioceptive and visual, central nervous system processing, and coordination of motor output are responsible for the changes in postural skills observed through adolescence. Infants and young children are dependent on the visual system to maintain balance. As they grow older, begin to use somatosensory and vestibular information properly. Between the 3 sensory inputs in children, the vestibular system seems to be the slightest effective in postural control.
Children with early sensorineural hearing loss and bilateral vestibular dysfunction present with delayed gross motor development. These children stand and walk later than their peers. Difficulties in maintaining balance can lead to challenges in normal childhood activities e.g. riding a bicycle or hopping. Reduced ability to participate in normal play with other children may result in social isolation. In hearing impaired children vestibular dysfunction is common. It was mentioned in a study held in 2013 that 88% of hearing impaired children suffer from vestibular dysfunction. This could mainly be due to hearing and vestibular impulses pass via the vestibule-cochlear nerve. Another study in 2018, found that vestibular dysfunction to be around 50% in hearing impaired children.
Gaze stability and Brandt-Daroff exercises are two different type of exercises which are used for rehabilitation of dizziness in hearing impaired patients. A type of habituation exercise is Brandt- Daroff exercises which are easy to perform. Brandt- Daroff exercises cause the debris to get dislodged from the cupula of the posterior semi-circular canal and will no longer effect cupula during the head movements. Bandt-Daroff exercises are performed with quick head rotations while watching a visual target and sustaining focus on the visual target during head movements. Gaze stability exercises designed to improve the gaze stability. These exercises require the individual to fixate on a visual target during horizontal or vertical head movement.
