E

Echocardiogram

This test uses sound waves or ultrasound to look at the structure of the heart. It is the same sort of machine which doctors use to look at babies in the womb.

EEG

The EEG (electroencephalogram) is a recording of the natural electrical activity of the brain. It involves placing small recording electrodes on the scalp and is completely painless and harmless. The analysis of the EEG can be very helpful in diagnosing various neurological diseases including
epilepsy and CJD.

Electrocardiogram (ECG)

This test measures the electrical impulses in the heart and indicates to the doctor whether the heart is healthy or not.

Electrode

Small cup-like metal discs placed on the scalp with a special paste to record the EEG or evoked potentials, or flexible stick-on discs or felt pads soaked in salt solution used to record the signals produced by stimulation of nerves for nerve conduction studies.

Electroencephalogram (EEG)

A procedure in which brain waves are recorded using electrodes which are stuck to the scalp.

Electromyography (EMG)

This is a test of the electrical activity of the nerves and muscles in the arms and legs.

Electrophysiology

A means of testing the function of nerves by electrical stimulation, recording responses from the skin and the muscles.

Encephalitis

Inflammation of the brain, usually caused by a viral infection. 
Read more information about encephalitis

Encephalopathy

Any disease or disorder affecting the brain.

Endolymphatic hydrops

The build-up of pressure in the inner ear that causes the vertigo attacks in Ménière’s disease.
Read more information about Ménière’s disease

ENG

An electro-nystagmogram is a recording of the eye movements during visual and rotating chair tests and is used to assess a person’s balance systems. The balance organs control the movement of the eyes and when
the balance organs or centres are damaged there can be nystagmus - an abnormal jerkiness of the eyes.

ENT

Medical field specialising in disorders of the ear, nose and throat.

Epidemic

This term is used for a disease that for most of the time is rare in the community, but that suddenly spreads to large numbers of people.

Epidemiological study

This is the study of disease as it affects groups of people or populations (as opposed to individuals).

Epidural

The name given to the space just outside the membranes which enclose the spinal cord and the nerves in the spinal canal. Injections into this space are sometimes used to provide pain relief by numbing nerves as they pass down the spine.

Epilepsy

Disorder of brain function usually characterised by recurrent attacks of unconsciousness (fits or seizures).
Read more information about epilepsy

Epileptic fit (seizure)

A sudden and short-lived electrical disturbance in the brain which often, but by no means always, causes abnormal shaking movements and a brief loss of consciousness.
Read more information about epilepsy

Epileptiform activity

Abnormal electrical signals seen in the EEG which are commonly associated with epilepsy. These include spikes, spike and wave and sharp waves.

Ergotamine

A drug extracted from a mould growing on rye which has been a mainstay of headache treatment for many years.

ESR (Erythrocyte Sedimentation Rate)

A blood test which often gives a general clue that a person is unwell. It is
abnormal, for example, in people with inflammatory disease of the arteries.

Evoked potentials

Electrical responses produced in the nervous system by stimulation of the eyes (visual evoked potentials), ears (auditory evoked responses) or sensory nerves in the limbs (somatosensory evoked potentials).

Expectant

Expectant management means that natural recovery is anticipated without specific medical treatment.

Expressive aphasia

See Non-fluent Aphasia.