The Dizzy clinic is a recent expansion to audiological services provided at Ahmadi Hospital. The Dizzy Clinic evaluates patients with complaints of any type of dizziness. Dizziness generally refers to a feeling of spatial disorientation. Types of dizziness include vertigo, lightheadedness, and imbalance. Disorders of the nervous system, including the vestibular system, are emphasized in this clinic. Common conditions diagnosed in this clinic include: benign paroxysmal positional vertigo, vestibular neuritis (i.e., labyrinthitis), Meniere's disease, cerebellar ataxia syndromes, cerebrovascular disorders, chronic dizziness and migraine-associated dizziness.
Balance involves the overlapping function of several systems, namely, the visual system, the proprioceptive system, and the vestibular system. The central nervous system, together with these systems maintain equilibrium. In the dizzy clinic different tests and maneuvers are conducted to help evaluate the integrity systems involved, particularly the central and the peripheral vestibular system. Tests may be conducted in more than one session. Depending on the symptoms and nature of the disease, the clinician determines the appropriate tests for each patient. The steps involved in vestibular evaluation are as follows:
Detailed case- history - Clearly understanding the symptoms experienced by the patient is one of the first and most crucial steps of the evaluation. The patient is asked to fill up a questionnaire on the signs and symptoms. The audiologist sits with the patient through this as the history allows the us to distinguish the type of dizziness and to make a hypothesis about the site and type of lesion.
Hearing evaluation -The hearing evaluation, which also includes tests of differential diagnosis, help to give insight into the nature of cause of dizziness. Tests conducted are:
1) Pure tone Audiometry
2) Speech Audiometry
4) Acoustic Reflex Testing
5) Auditory Brainstem Responses
6) Otoacoustic Emissions
7) Auditory Steady State Responses
c) Specific office tests of balance- The following physical examinations are effective in evaluating the dizzy patient and give the clinician a direction into the cause and nature of dizziness and give important information for distinguishing peripheral and central vertigo. These tests include:
1) Test for spontaneous nystagmus
2) Gaze test
3) Gait stability test
4) Head shake
5) Head thrust test
6) Dynamic visual acuity
7) Romberg test
8) Fukuda Stepping test
9) Voluntary hyperventilation
Vestibular Laboratory tests – These tests are warranted to give diagnostic information as well as confirm and quantify the findings.
Video Nystagmography (VNG) - relies on the vestibulo-ocular reflex to test the peripheral vestibular function and its ability to generate efficient voluntary eye movements necessary for maintaining visual contact with the environment. It involves the use of infrared goggles to trace eye movements during visual stimulation and positional changes. It consists of the following subtests:
1) Oculomotor tests: Test eye movements that originate in the cerebellum. Abnormalities in these tests usually suggest a central neurological origin. Tests include:
a) Saccadic Tracking
b) Smooth Pusuit test
c) Optokinetic test
2) Gaze test: Records eye movements as the patient fixates on targets at different positions.
3) Spontaneous nystagmus test: Records eye movement in center gaze both with and without fixation.
4) Hyperventilation test
5) Positional and positioning tests: Test for abnormalities in the vestibular system. Positional tests are performed to determine whether the vestibular system responds normally and symmetrically to changes in head position. Tests include:
a) Static Position test
b) Dix–Hallpike test (for BPPV of posterior canal)
c) Roll Maneuver (for BPPV of lateral canal)
6) Caloric tests: Test that stimulates one side of the vestibular system at a time. The responses of each inner ear to warm and cold stimulation in the ear canal is measured and used to detect possible vestibular weakness.
Rotatory Chair Testing: The purpose of rotational testing is to determine whether or not dizziness may be due to a disorder of inner ear or brain, and particularly to determine whether or not both inner ears are impaired at the same time. It is conducted by securing the patient to a rotary chair which rotates at various speeds and directions while eye movements are recorded. There are three parts to the test:
a) Sinusoidal Harmonic Acceleration
b) Visual-Vestibular Interaction Test
c) Vestibular Ocular Reflex Suppression Test
d) Step Velocity Testing
Vestibular Evoked Myogenic Potential (VEMP) - A neurophysiological assessment technique used to determine the function of the otolithic organs (utricle and saccule) of the inner ear. It complements the information provided by caloric testing and other forms of inner ear (vestibular apparatus) testing.
Electrocochleography (ECoG) - Electrocochleography (ECOG) is a specialized test which measures the electric potentials or signals generated in the inner ear in response to sound. ECOG may be used to help diagnose whether you have any disease which may cause an accumulation of inner ear fluid, such as Ménière’s disease.
With the help of the above mentioned tests, the clinician arrives at the most appropriate diagnosis. The object of the evaluation is to separate possible causes into the categories of life threatening or benign, and to distinguish easily treatable causes from more complex causes.
In addition to diagnostic testing, we also carry out vestibular rehabilitation through counseling, various maneuvers and home exercises. Most patients diagnosed with Benign Positional Paroxysmal Vertigo (BPPV) have shown remarkable improvement using the canalith repositioning procedure with a vibrator. We also offer a multidisciplinary approach to balance disorders by combining the expertise of a competent ENT consultant and a well - experienced physiotherapist.