N

Natural history

This term refers to what will happen if a disease remains untreated. It could become worse, remain much the same or simply get better on its own.

Nasal resonance

The quality of sound resulting from the amount of air that passes through the nose during speech.

Nasogastric tube

See feeding tubes.

Nausea

Feeling the need to vomit without necessarily doing so.

Needle electrode

A fine electrode inserted into a muscle to record its electrical activity during EMG.

Neglect

People with neglect ignore the side of their body which has been affected by the stroke and may even deny owning an affected arm or leg.They may also ignore people approaching them from that side and may not respond to people on that side.

Nerve cell

The basic functional unit of the nervous system.These specialised cells transmit chemicals and electrical impulses and so carry information from one part of the body to another.

Nerve conduction studies

A diagnostic technique involving the electrical stimulation of nerves in the limbs to measure the passage of nerve impulses along them.

Nerve fibre

A long thread that extends from a nerve cell and carries nerve impulses. Bundles of nerve fibres running together form a nerve.

Nerve root

The term used to describe a main nerve trunk as it arises from the spinal canal. It soon divides into a number of branches, some of which join with other nerve roots and go on to supply various parts of the body including muscle groups (myotomes) and specific areas of skin (dermatomes).

Neuralgic

A term used to refer to pain generated by direct stimulation of a nerve. It has distinct qualities and may be of use in diagnosing the exact site of origin of the pain.

Neurofibroma

A benign growth of nerves, usually solitary. May be multiple in neurofibromatosis. Similar to schwannoma.

Neuroleptics

Drugs which block dopamine receptors and which are used to treat severe psychiatric diseases

Neurological

Refers to conditions occurring in the nervous system, including the brain, spine and all the peripheral nerves.

Neurologist

A medical doctor who is specially trained to diagnose disorders of the brain, spinal cord and nerves, and to treat them with drugs if appropriate.

Neuromuscular

Involving the nerves and muscles.

Neuron

Another term for a nerve cell. They are the key cells in the central nervous system that produce and carry the electrical impulses or messages that translate our thoughts into actions. Their long projections or extensions are called axons.

Neuroradiologist

A doctor who is specially trained to conduct and interpret CT and MRI scans and angiograms. Sometimes, neuroradiologists are not just trained to diagnose, but also to treat using techniques such as embolisation.

Neurosurgeon

A doctor who is specially trained to diagnose and treat people with disorders of the brain, spinal cord and peripheral nerves using surgical techniques.

Neuro-transmitter

A chemical messenger used by the nerve cells.

Nervous system

The vast network of nerve cells which carries information to and from all parts of the body in order to bring about bodily activity. It is classically divided into the brain, spine and peripheral nervous system.

Nidus

The knotted tangle of blood vessels in an arteriovenous malformation. Nidus is the Latin word for nest.

Non-fluent aphasia

A form of aphasia usually resulting from damage to an area near the front of the left side of the brain and characterised by slow, halting language, often with poor sentence structure and grammatical errors but which may contain some meaningful words.

Non-invasive

A procedure that does not involve making an incision or introducing an instrument into the body for diagnosis or treatment.

Nucleus

The term used to refer to the inner part of an intervertebral disc. A high water content in youth provides support for the spine, with resistance to compression. With advancing years the water content declines, the nucleus becomes compressible and the annulus of the disc begins to bulge.

Nystagmus

Abnormal, jerky movements of the eyes.