Definitions - Neurological Conditions - N

Narcolepsy - a neurological condition most characterized by Excessive Daytime Sleepiness (EDS). A narcoleptic will most likely experience disturbed nocturnal sleep, which is often confused with insomnia, and disorder of REM or rapid eye movement sleep. It is one of the dyssomnias. A narcoleptic may also sleep at any random time.

Neuroacanthocytosis - a rare movement disorder marked by progressive muscle weakness and atrophy, progressive cognitive loss, chorea (involuntary twisting movements of the body), and acanthocytosis (spiked red blood cells associated with several inherited neurological disorders). Other symptoms include facial tics, uncontrolled muscle movement, instability when walking, seizures, biting of the tongue and lips, and changes in personality, comprehension, and judgment.

Neurodegeneration with Brain Iron Accumulation - (NBIA) is a rare, inherited, neurological movement disorder characterized by progressive degeneration of the nervous system. Symptoms, which vary greatly among patients and usually develop during childhood, may include slow writhing, distorting muscle contractions of the limbs, face, or trunk, choreoathetosis (involuntary, purposeless jerky muscle movements), muscle rigidity (uncontrolled tightness of the muscles), spasticity (sudden, involuntary muscle spasms), ataxia (inability to coordinate movements), confusion, disorientation, seizures, stupor, and dementia.

Neurofibromatosis - an autosomal dominant genetic disorder. It encompasses a set of distinct genetic disorders that cause tumors to grow along types of nerves and, in addition, can affect the development of non-nervous tissues such as bones and skin. The tumors can grow anywhere on or in the body.

Neuroleptic Malignant Syndrome - (NMS) is a life-threatening, neurological disorder most often caused by an adverse reaction to neuroleptic or antipsychotic drugs. It generally presents with muscle rigidity, fever, autonomic instability and cognitive changes such as delirium, and is proven on a raised creatine phosphokinase (CPK). Treatment is generally supportive.

Neurological Complications of AIDS - AIDS is primarily an immune system disorder caused by the human immunodeficiency virus (HIV), but it can also affect the nervous system. HIV does not appear to directly invade nerve cells but it jeopardizes their health and function, causing symptoms such as confusion, forgetfulness, behavioral changes, severe headaches, progressive weakness, loss of sensation in the arms and legs, stroke, cognitive motor impairment, or damage to the peripheral nerves. Other complications that can occur as a result of HIV infection or the drugs used to treat it include pain, seizures, shingles, spinal cord problems, lack of coordination, difficult or painful swallowing, anxiety disorder, depression, fever, vision loss, gait disorders, destruction of brain tissue, and coma.

Neurological Complications Of Lyme Disease - Lyme disease is caused by a bacterial organism that is transmitted to humans via the bite of an infected tick. Most people bitten by an infected tick develop a characteristic skin rash around the area of the bite. The rash may feel hot to the touch, and vary in size, shape, and color, but it will often have a "bull's eye" appearance (a red ring with a clear center). However, there are those who will not develop the rash, which makes Lyme disease hard to diagnose because its symptoms and signs mimic those of many other diseases.

Neurological Consequences of Cytomegalovirus Infection - CMV is in the same family of viruses that includes herpes simplex types 1 and 2, and the viruses that cause infectious mononucleosis (EBV), chickenpox, and shingles. A hallmark of CMV is the reappearance of symptoms throughout life, as the virus cycles through periods of dormancy and active infection.

Neurological Manifestations of Pompe Disease - Pompe disease is a rare inherited and often fatal disorder that disables the heart and muscles. It is caused by mutations in a gene that makes an enzyme called alpha-glucosidase (GAA). Normally, the body uses GAA to break down glycogen, a stored form of sugar used for energy. But in Pompe disease, mutations in the GAA gene reduce or completely eliminate this essential enzyme. Excessive amounts of glycogen accumulate everywhere in the body, but the cells of the heart and skeletal muscles are the most seriously affected.

Neurological Sequelae Of Lupus - is a disorder of the immune system. Normally, the immune system protects the body against invading infections and cancers. In lupus, the immune system is over-active and produces increased amounts of abnormal antibodies that attack the body's tissues and organs. Lupus can affect many parts of the body, including the joints, skin, kidneys, lungs, heart, nervous system, and blood vessels.

Neuromyelitis Optica or Devic's disease - an autoimmune, inflammatory disorder in which a person's own immune system attacks the optic nerves and spinal cord. This produces an inflammation of the optic nerve (optic neuritis) and the spinal cord (myelitis). Although inflammation may also affect the brain, the lesions are different to those observed in the related condition multiple sclerosis. Spinal cord lesions lead to varying degrees of weakness or paralysis in the legs or arms, loss of sensation, and/or bladder and bowel dysfunction. Devic's disease is a rare disorder which resembles multiple sclerosis (MS) in several ways.

Neuromyotonia - also known as Isaacs' Syndrome, is spontaneous muscular activity resulting from repetitive motor unit action potentials of peripheral origin.

Neuronal Ceroid Lipofuscinosis - (NCL, also known as Batten Disease) is the general name for a family of at least eight genetically separate neurodegenerative disorders that result from excessive accumlation of lipopigments (lipofuscin) in the body's tissues. These lipopigments are made up of fats and proteins. Their name comes from the technical word lipo, which is short for "lipid" or fat, and from the term pigment, used because they take on a greenish-yellow color when viewed under an ultraviolet light microscope. The lipopigments build up in cells of the brain and the eye as well as in skin, muscle, and many other tissues.

Neuronal Migration Disorders - (NMDs) are a group of birth defects caused by the abnormal migration of neurons in the developing brain and nervous system.

Neuropathy - Hereditary - a group of inherited disorders of the peripheral nervous system. Within the group there are 4 subcategories of disorders, including hereditary motor and sensory neuropathy, hereditary sensory neuropathy, hereditary motor neuropathy, and hereditary sensory and autonomic neuropathy. Symptoms of these disorders vary and may include numbness and tingling in the feet and hands, muscle weakness (especially in the distal muscles), scoliosis, thin lower legs, foot deformities, insensitivity to pain, and autonomic symptoms such as impaired sweating, postural hypotension, and skin blotching.

Neurosarcoidosis - refers to sarcoidosis, a condition of unknown cause featuring granulomas in various tissues, involving the central nervous system (brain and spinal cord). It can have many manifestations, but abnormalities of the cranial nerves (a group of twelve nerves supplying the head and neck area) are the most common. It may develop acutely, subacutely, and chronically.

Neurotoxicity - occurs when the exposure to natural or manmade toxic substances, which are called neurotoxins, alters the normal activity of the nervous system. This can eventually disrupt or even kill neurons, key cells that transmit and process signals in the brain and other parts of the nervous system. Neurotoxicity can result from exposure to substances used in chemotherapy, radiation treatment, drug therapies and organ transplants, as well as exposure to heavy metals such as lead and mercury, certain foods and food additives, pesticides, industrial and/or cleaning solvents, cosmetics, and some naturally occurring substances.

Nevus Cavernosus - or cavernous angioma, vascular malformation composed of sinusoidal vessels without a large feeding artery; can be multiple, especially if inherited as an autosomal-dominant trait.

Niemann-Pick Disease - an autosomal recessive disorder affecting lipid metabolism (the breakdown and use of fats and cholesterol in the body), in a way which causes harmful amounts of lipids to accumulate in the spleen, liver, lungs, bone marrow, and brain.

Normal Pressure Hydrocephalus - (NPH) is an abnormal increase of cerebrospinal fluid (CSF) in the brain's ventricles, or cavities. It occurs if the normal flow of CSF throughout the brain and spinal cord is blocked in some way. This causes the ventricles to enlarge, putting pressure on the brain.