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A to Z of neurological topics

In this section we feature information on a number of tests, treatments and conditions, with links for more information either within this website or on external sites where possible. If you can't find what you're looking for, you may wish to speak with one of our Helpline team who may be able to answer your questions. Send an email to [email protected] or call free on 0808 808 1000.

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    Capillary telangiectasia


    Small areas, or clusters, of abnormally dilated capillaries (small blood vessels) that are seen within otherwise normal brain tissue


    See our Vascular malformations of the brain booklet



    A flexible tube use in medical procedures.

    Cauda equina syndrome


    Cauda equina syndrome is a condition in which the bundle of nerves that sits below the spinal cord in the spinal column, often referred to as the cauda equina, is compressed. It can cause pain in the lower back or legs, numbness or weakness in the legs and groin, and can affect bowel or bladder control, as well as sexual function.



    Causalgia is an older term for what is now more often described as type 2 complex regional pain syndrome.


    See complex regional pain syndrome for more information.



    A cavernoma is a cluster of abnormal blood vessels, usually found in the brain and spine. Unlike arteriovenous malformations, cavernomas do not have well defined arteries or veins connecting to them.


    See our Vascular malformations of the brain booklet

    Cerebellar tonsils


    The cerebellar tonsils are the lowest part of the cerebellum.



    The cerebellum is the lowermost part of the brain, and plays a role in controlling balance and co-ordinating movement.

    Cerebral palsy


    A group of neurological conditions that affect muscle control, movement and co-ordination. These conditions are often caused by damage to the brain that occurs before, during or soon after birth.


    Useful links:


    Cerebrospinal fluid (CSF)


    A clear, colourless fluid that surrounds the brain and spinal cord. Its main functions are to protect the brain and to carry nutrients to the brain and remove waste.

    Cerebrospinal fluid (CSF) leak


    A cerebrospinal fluid leak occurs when there is a tear or hole in the membranes that surround the brain and spinal cord, and the fluid that surrounds these structures escapes. As a result of this leak, the overall pressure within the skull can drop (which is referred to as intracranial hypotension) and this can cause headaches as well as other neurological symptoms.


    See our Headache booklet


    Useful links:

    CSF Leak Association

    Charcot-Marie-Tooth disease


    A group of inherited conditions that affect the nerves that lie outside of the brain and spinal cord (peripheral nerves) and can cause problems with muscle control and sensation.


    Useful links:

    CMT United Kingdom

    Chiari malformation


    A medical term describing when the cerebellum, and sometimes the brainstem, extends below the foramen magnum and into the spinal canal. This can put pressure on the brain stem and spinal cord, and also disrupt the flow of cerebrospinal fluid, which can cause a wide range of symptoms including headache, dizziness, and neck pain.


    See our Chiari malformations fact sheet



    A type of tumour that can occurs in the bones in the spine and at the base of the skull.


    See our Spinal tumours booklet

    Chronic fatigue syndrome (CFS)

    (also known as myalgice encephalomyelitis or ME)


    A condition that can cause a wide range of symptoms, of which the most common is extreme tiredness or fatigue. It is not known what causes CFS/ME, but it is thought that in some cases it occurs following an infection or illness such as glandular fever or pneumonia.


    Useful links:

    ME Association

    M.E Support

    Clinical Nurse Specialist


    A Clinical Nurse Specialist (CNS) is a registered nurse who is an expert within a specialty area.



    A way of treating aneurysms by putting a small clamp around their base. This kind of procedure requires a craniotomy or open surgery.


    See our Subarachnoid haemorrhage booklet

    Cluster headache


    A recurrent type of headache that typically occurs in a cyclical pattern or in clusters, and that causes a severe pain in or around one eye on one side of the head. Other symptoms that occur with a cluster headache can include a red and watery eye, drooping and swelling of one eyelid, or a blocked or runny nostril.


    See our Headache booklet


    Useful links:

    OUCH (UK)

    CNS nurse


    See Clinical Nurse Specialist

    Cognitive behavioural therapy (CBT)


    A form of talking therapy that can help you manage your problems by changing the way you think and behave.



    A way of treating aneurysms without the need for a craniotomy or open surgery, that is performed by going through the blood vessels and inserting a coil of metal in to the aneurysm.


    See our Coiling of brain aneurysms fact sheet

    Colloid cyst


    A type of tumour/fluid filled sac that is found in the brain, but that is often found incidentally as they can be asymptomatic.

    Complementary therapies


    Non-mainstream types of medicine and treatment that are used alongside conventional medical treatments.


    Useful links:

    Hypnotherapy directory

    Therapy directory

    Complex regional pain syndrome (CRPS)


    Complex regional pain syndrome is a condition in which someone experiences severe ongoing pain in a limb or specific part of the body, which most often occurs following an injury.


    Useful links:




    A temporary injury to the brain that can be a consequence of a minor head injury. A concussion can cause headaches, dizziness, nausea and vomiting, and can also cause someone to be confused or have memory problems for a short period of time.



    This term refers to something, such as a condition, that has been present since birth. However, it may not become apparent until later in life and may be found incidentally.



    As a medical term, continence generally refers to the ability of a person to control, or ‘hold back,’ functions of the bladder and the bowels.


    Useful links:

    Bladder and Bowel Foundation

    Counselling and psychotherapy


    Useful links:

    It’s good to talk

    UK & Ireland Directory of Counselling and Psychotherapy

    Counselling Directory



    A person trained to give guidance on personal or psychological problems.



    An operation in which an opening is made in the skull.


    See our Craniotomy fact sheet

    Creutzfeldt-Jakob disease (CJD)


    A degenerative brain disease that is most commonly caused by an infectious protein called a prion.


    Useful links:

    CJD Support Network

    National CJD Surveillance Unit

    CSF leak


    See Cerebrospinal (CSF) fluid leak

    CT scan


    A CT scan is a Computerised Tomography scan. It is a special type of X-ray that uses a scanner and computer equipment to take cross-sectional pictures of the brain or spine.


    See our Brain and Spine scans fact sheet

    CTA scan


    A CTA scan is a Computerised Tomography Angiography (CTA) scan. It is a special type of X-ray that involves injecting a special dye in to the bloodstream, and uses a scanner and computer equipment to take cross-sectional pictures of specific blood vessels