Neurophysiology

The department has particular expertise in paediatric neurophysiology (EEG).

This test records the electrical activity in the brain and it is used to:

·         differentiate between types of seizures and to add support to a diagnosis of epilepsy

·         assist in the classification of epilepsies and syndromes

·         detect or confirm photosensitivity

·         detect non-convulsive status epilepticus

·         monitor status epilepticus

·         assess state in coma

·         assess confusional states

·         confirm ‘classic’ sporadic CJD

·         assess the early stages of vascular events (when a CT scan appears normal).

For the test small contacts are placed on the scalp; the test is painless and there are no after effects. On average it will take between 45 minutes and one and a half hours. During the test patients may be asked to do some deep breathing or to look at a flashing light. Often the appointment is arranged so that the patient will fall asleep during the recording, which may give additional information to aid diagnosis.

EPs (Evoked Potentials)

These tests measure the brain’s responses to particular stimuli. They are

used to investigate:

·         multiple sclerosis

·         auditory nerve lesions

·         optic pathway lesions

·         central nervous system dysfunction in peripheral disorders

·         integrity of visual pathways

The tests are painless and there are no after effects. They take about an hour at the most for adults but may take longer for babies.

The visual EPs involve a patient looking at a checkerboard pattern or a flashing light on a screen and are used to test the speed and shape of responses in the nerves from the eyes. Patients who wear glasses should bring them along to the test.

The auditory EPs require the patient to wear a pair of earphones. A rapid clicking noise produces tiny signals in the nerve from the ear.

The somato-sensory EPs involve applying small pulses to the wrist. These can be felt but do not hurt. The signals travelling along the nerves of the arm to the brain are measured by contacts on the collarbone, neck and scalp. Sometimes this test is done on the leg. Patients are advised to wear loose open-necked clothing for this test.

EMG (Electromyography) and NCS (Nerve conduction studies)

These tests are used in the evaluation of muscle and large myelinated nerve fibre function. They are used to:

·         confirm or exclude CTS, or other nerve entrapments

·         identify radiculopathies

·         confirm or exclude neuropathies

·         diagnose Motor Neurone Disease

·         identify myopathies

·         assess post-traumatic injury/recovery

Preparation