Neurophysiology

​What is neurophysiology?

Neurophysiology involves the recording of electrical responses in the brain or nervous system. It includes tests such as electroencephalograph (EEG), nerve conduction studies, evoked potentials and electromyography.

These diagnostic tests may be used for conditions such as epilepsy, seizures, sleep disorders, stroke, brain tumours and peripheral neuropathies.

 

​Referrals

Neurophysiology services are available to adults, children and neonates and are provided at Gosford and Wyong Hospitals. Some tests are only performed at Gosford Hospital.

To be referred to this service as an outpatient (this means that you are not currently a patient in the hospital) you will need a referral from your GP or specialist doctor.

If further testing is required a neurologist from the neurophysiology team will co-ordinate.

Contact us

Contact the neurophysiology reception on 4320 3277 Monday to Friday 8am to 4.30pm for any enquiries including questions relating to the tests.

Fax 4320 2262.

Getting here

Gosford Hospital

Neurophysiology is located in the diagnostic services department close to the hospital's main reception. At the main entrance turn left around the reception and the diagnostic services department is straight ahead.

Wyong Hospital

Neurophysiology is located with the cardiac diagnostics service close to the hospital's main entrance. At the main reception take the first corridor to the right and neurophysiology is located at the first door on your left.

What is an EEG?

An electroencephalograph (EEG) is a medical test that records and measures the electrical activity in the brain. EEGs can assist in the diagnosis of several conditions including epilepsy, sleep disorders, stroke and brain tumours.

The procedure consists of placing small metal electrodes on the scalp and recording the electrical activity in the brain. The results of the test are read by a neurologist.  

There are a number of different EEGs including a routine EEG, a sleep deprived EEG, a pro-longed EEG (usually takes 3 hours) and telemetry monitoring. Multiple sleep latency testing (MSLT) is also undertaken.  The MSLT tests for excessive daytime sleepiness by measuring how quickly you fall asleep during the day.

What is a routine EEG?

A routine EEG is the standard EEG that is requested by most doctors. It involves placing small metal electrodes on the scalp and taking a 20 minute recording of the electrical activity in the brain. From start to finish the whole process usually lasts about 45 to 60 minutes.  

What is a "sleep deprived" EEG?

A sleep deprived EEG is measured in the same way as a routine EEG however the recording time is longer at one hour plus you will be asked to stay awake for 24 hours prior to the test. You are able to sleep during the EEG.

If the test is to be performed on a child you will be advised how to prepare your child and adjust their sleep pattern prior to the test dependent on their age.

Sleep deprived EEGs may be used if a standard EEG has been inconclusive or if the specialist requests further investigation.

Prolonged EEGs and telemetry monitoring

It is not always possible to capture an episode, seizures and abnormalities using a standard or sleep deprived EEG. For some patients a neurologist will request a prolonged EEG and telemetry monitoring.

A prolonged EEG lasts for 3 hours while telemetry monitoring usually occurs over a few days.

How to prepare for an EEG

Before a routine EEG

  • wash and dry your hair the night before the test
  • do not use hair products
  • take your routine medication prior to the test and when required and eat a good meal prior to testing.

Before a "sleep deprived" EEG

  • wash and dry your hair the night before the test
  • do not use hair products
  • take your routine medication prior to the test and when required
  • patients 13 years and above are to stay awake the night before the test
  • patients aged 5 to 12 years are to have 4 hours sleep only - going to bed 3 hours later and waking 3 hours earlier
  • for children younger than 5 years contact the neurophysiology reception for instructions
  • do not consume any caffeine prior to the sleep deprived EEG - this includes, coffee, tea, chocolate, any cola drinks or energy drinks of any sort but do eat a good breakfast.
  • adult patients are asked that someone else drive them to and from the test.

Before prolonged and telemetry monitoring

Please contact the neurophysiologist receptionist for instructions concerning these tests.

During the EEG

You will be seated in a comfy reclining chair throughout the test. A technician who will conduct the EEG will mark and measure your head with a special pencil to identify where the electrodes will be placed.

Over 20 small metal electrodes will be stuck to your head using a special paste (that will wash out). The recording will then commence for the duration required depending on the test type (20 minutes for a standard EEG).

Halfway through the routine EEG the technician will ask you to perform some light hyperventilation for three minutes.

Your eyes remain closed for most of the testing however, towards the end of the test the technician will ask you to open and close your eyes while a strobe light is flashed in your eyes.

After the test

Once the EEG is complete the electrodes are removed from your scalp which is wiped to wash off any excess paste. Any paste remaining in the hair will wash out when you wash your hair as normal.

Results of the test will be sent to the doctor who requested the EEG.

Nerve conduction study

A nerve conduction study is a test that gives doctors information on how well and how fast your nerves send electrical impulses. This study is used to test a variety of different problems with the peripheral nervous system. The peripheral nervous system includes all the nerves in your body apart from those in your brain and spinal cord. The brain and spinal cord nerves make up the central nervous system.

A nerve conduction study consists of placing several recording electrodes on your skin over specific nerves to record the electrical response from the nerve. Nerve conduction studies are performed at Gosford Hospital.

How to prepare for a nerve conduction study

Avoid putting moisturiser on prior to the test. If you are taking blood thinners or have a cardiac defibrillator or pacemaker let the technician know.

No other pre-test preparation is required.

Electromyography

Electromyography is used to test for evidence of muscle disease by inserting a small electrode into the muscle and recording the electrical activity.

An electromyography test may also be performed as part of the nerve conduction study.

Evoked potentials

Evoked potentials test the electrical activity of a single nerve pathway for evidence of disease or obstruction along the pathway.

Evoked potentials performed at Gosford Hospital are:

  • Visual evoked potentials (VEP) that record the activity of the optic nerve and involve the patient looking at patterns.
  • Brain auditory evoked potentials (BAEP) test the auditory stimulation of the auditory nerve and involve listening to sounds.

Somato-sensory stimulation (SSEP) records the electrical stimulation of the upper and lower limbs (arms and legs).