Patient Information

Electroencephalography (EEG): A series of small non-invasive electrodes are attached to your head to measure the brain’s electrical signals. The technician will inform you during set-up what is required during the test but, for most of the time, you will be lying with your eyes closed and as relaxed as possible (even asleep).

Prolonged EEG: The same electrodes are attached as for a routine EEG but his recording is extended for a further 3-4 hour period. The head electrodes are attached to a portable recorder so you will be able to move around, although the best recording is obtained while you are seated quietly. Please bring along suitable reading matter so that you can occupy your time during this EEG recording.

Sleep-deprived EEG: This recording is performed following sleep-deprivation for a 24 hour period. Please note that you must not sleep the night before the test; you must avoid using any stimulants such as caffeine, alcohol and nicotine to help you stay awake; and you must not drive to or from our rooms (and someone should come with you if public transport is used). 

Event-related potentials (P300): Electrodes are placed on your head to measure cognitive processes while you listen through headphones and concentrate on certain sounds. You do need to be alert and able to concentrate throughout this test.

Cognitive testing: This test sequence measured memory and cognitive function. The computerised tests ask you to tap a screen in response to a series of questions. You are also asked to complete a series of tasks from a small booklet.

Perimetry:  A simple and fast test of your peripheral visual field where you press a button whenever you see a light turn on.

Visual evoked responses (VER): A visual stimulus (checkerboard pattern) stimulates the optic nerves and a response is recorded on computer via 6 electrodes placed on your head. You must remain alert throughout the test to prevent a false reading.

Nerve conduction studies (NCS): These are electrophysiological studies, usually of the arms or legs, where electrical stimulation of selected nerves measure the responses of the motor and sensory nerve fibres.

Thermal sensory analysis (TSA): A flat plate or thermode, which changes temperature, will be strapped to your skin and you will be asked to indicate (with a push-button) when you feel the temperature changing. This test measure the sensitivity of these receptors and the small nerve fibres supplying them.

Somatosensory evoked potentials (SSEP): Selected nerves are stimulated to detect any slowing in conduction in the nerve pathways. Non-invasive electrodes will be attached to your head to measure when the nerve responses reach the brain.  Only a slight electrical tapping sensation will be felt when each nerve is stimulated electrically.

Vestibulocochlear evoked potentials: These tests include the studies listed below.

Audiometry & Tympanometry: general hearing tests

Brainstem auditory responses (BAER): Clicking sounds via headphones stimulate the auditory nerves. Electrodes are placed behind the ears and on the head to record responses from the auditory nerves while you are relaxed and lying quietly. 

Vestibular evoked potentials (VEMP): Measures the response of the balance system from small electrodes are placed over muscles of the neck or face after clicking sounds are heard through headphones or after light taps on the forehead.

Vestibular function testing (VFT): These tests include the 4 sets of tests which are listed below:

Audiometry & Tympanometry: general hearing tests

Brainstem auditory responses (BAER): Clicking sounds via headphones stimulate the auditory nerves. Electrodes are placed behind the ears and on the head to record responses from the auditory nerves while you are relaxed and lying quietly

Vestibular evoked potentials (VEMP): Measures the response of the balance system from small electrodes are placed over muscles of the neck or face after clicking sounds are heard through headphones or after light taps on the forehead.

Video Head Impluse Testing (vHIT): 
the patient wears a pair of light weight tightly fitting goggles with a silvered mirror which reflects the image of the patient’s eye into a very small camera. The patient fixates on a target while the technician gives the patients head very quick horizontal and vertical head rotations at a very small angle of about 10-20 degrees. The small sensor on the googles measures the head and eye movement. This test is used in the assessment of patients with complaints of dizziness, disequilibrium and vertigo. SPECIAL INSTRUCTIONS: Please DO NOT wear any eye makeup ESPECIALLY MASCARA for this test.