Nervous System Diseases and Conditions

Alzheimer’s disease (AD)

A form of dementia (progressive mental deterioration) resulting from atrophy of the frontal and occipital lobes of the brain.

amnesia

Complete or partial loss of memories.

amyotrophic lateral sclerosis (ALS)

A disease marked by muscular weakness and atrophy with involuntary contractions and excessive reflexes; caused by the degeneration of motor neurons in the spinal cord and in the brain’s medulla and cortex.

anorexia nervosa

A condition involving restricted eating, fear of gaining weight, and distorted body image.

anxiety disorders

A group of mental illnesses that share the core characteristic of anxiety (excessive worry, nervousness, or uneasiness).

astrocytoma

A tumor of the neuroglial tissue.

attention-deficit/hyperactivity disorder (ADHD)

Condition in which a person is frequently distracted, is hyperactive, and displays a lack of impulse control.

aura

A subjective sensation that often occurs before a migraine or seizure.

autism spectrum disorder (ASD)

A developmental disability characterized by difficulty communicating with others and focusing beyond oneself; inability to maintain eye contact; motor activity that is repetitious; and preoccupation with small objects.

Bell’s palsy

A condition characterized by a unilateral (one-sided) paralysis of the nerves that control the facial muscles, causing one side of the face to droop.

binge-eating disorder

The most common eating disorder in the United States; characterized by compulsive overeating, including a sense of loss of control.

bipolar disorder

A mental illness characterized by alternating periods of mania (emotional "highs") and depression (emotional "lows").

brain tumor

Any intracranial mass, which may be neoplastic (a new growth), cystic (a sac containing fluid), or inflammatory (an abscess).

bulimia nervosa

An eating disorder characterized by binge eating that is followed by induced vomiting, use of laxatives, and/or excessive exercise; often abbreviated to bulimia.

cerebral aneurysm

An abnormal, localized (limited to one area) dilation of a blood vessel in the cerebrum.

cerebral contusion

A bruising in the cerebral tissue.

cerebral palsy (CP)

A disability that affects movement and muscle tone; caused by a condition in, or trauma to, the brain before birth.

cerebrovascular accident (CVA)

The death of brain tissue that occurs when an arterial blockage or arterial rupture prevents blood flow to the brain; commonly called stroke.

coma

A state of extended unconsciousness caused by a medical crisis, such as a traumatic brain injury (TBI), stroke, infection, or illness (diabetes, for example).

concussion

A traumatic brain injury (TBI) resulting from a blow to the head or violent shaking of the head and upper body; causes partial or complete loss of brain functions, which can result in memory loss, impaired coordination, difficulty with balance, and dizziness.

contusion

A bruise to the brain itself.

convulsion

A sudden, abnormal, involuntary contraction (or series of contractions) of the muscles.

delirium

A state of mental confusion and agitation characterized by disorientation of time and place, usually accompanied by hallucinations (false sensory experiences that are perceived as real) and illusions (misperceptions of environmental stimuli).

dementia

A condition of progressive mental deterioration caused by organic brain disease (that is, caused by tissue changes in the brain), which is characterized by memory loss, difficulties with language expression, and inability to perform ordinary daily activities of living.

depression

A mood disorder marked by persistent feelings of sadness, worthlessness, and lack of interest in daily activities.

developmental disabilities

Complex, long-term conditions that develop before adulthood and affect physical development, intellectual development, or both.

dyslexia

A learning disorder characterized by difficulty in recognizing and comprehending written language; affects reading and spelling abilities as well as self-expression.

eating disorders

A group of mental illnesses characterized by an unhealthy focus on weight and food.

epidural hematoma (EDH)

A mass of blood that forms between the skull and the dura mater as a result of the brain colliding against the skull, such as from a head injury or a fall.

epilepsy

A neurological disorder of the central nervous system in which the activity of the neural cells in the brain becomes disrupted, causing seizures, unusual sensations, repeated twitching of the limbs, and, occasionally, loss of consciousness.

focal seizure

Abnormal electrical activity that occurs in one or more parts of one brain hemisphere; also known as a partial seizure.

generalized anxiety disorder (GAD)

An anxiety disorder characterized by excessive worry that is not restricted to specific situations or objects; often associated with physical symptoms such as heart palpitations, chest pain, tremors, sweating, nausea, or headaches.

grand mal seizure

An epileptic seizure characterized by violent muscle contractions and loss of consciousness; also known as a tonic-clonic seizure.

Guillain-Barré syndrome (GB syndrome)

Polyneuritis (inflammation of multiple peripheral nerves) characterized by progressive muscle weakness of the extremities, which may lead to paralysis; usually occurs during or after recovery from an infectious disease.

headache (HA)

Pain that is spread out in one or more parts of the head; unconfined to a particular area of nerve distribution.

hemiplegia

Paralysis of one side of the body; also known as hemiparesis.

hemorrhagic stroke

A type of cerebrovascular accident (CVA) that occurs when a weakened blood vessel, such as an aneurysm, ruptures and bleeds into the surrounding tissue of the brain.

hydrocephalus

An accumulation of excess cerebrospinal fluid inside the ventricles of the brain, which causes cephalomegaly (enlargement of the head) and which may cause brain damage; commonly seen in young children.

intellectual disability (ID)

A condition of below-average intelligence resulting in the inability to develop skills necessary for daily living; also known as intellectual development disorder (IDD).

ischemic stroke

A type of cerebrovascular accident (CVA) that occurs when a blood vessel that supplies blood to the brain becomes occluded (blocked).

meningitis

Inflammation of the meninges.

meningocele

Congenital hernia in which the meninges protrude through an opening of the skull or spinal cord.

migraine

A headache that produces intense throbbing and pain in one area of the head and that is typically accompanied by nausea and/or vomiting and hypersensitivity to light and sound.

mood disorders

A group of mental illnesses marked by depression that may alternate with periods of elation (feelings of happiness).

multiple sclerosis (MS)

A chronic, slow-progressing disease of the central nervous system marked by development of thin, demyelinated (without myelin) glial patches called plaques.

myasthenia gravis (MG)

A disease of the skeletal muscles caused by disruption in neural communication between the muscles and the nerves; marked by severe weakness and fatigue.

myelomeningocele

A form of spina bifida (split spine) marked by protrusion of a portion of the spinal cord and the meninges through the spine.

narcolepsy

A condition characterized by an overwhelming tendency to fall asleep and sudden sleep attacks.

obsessive-compulsive disorder (OCD)

A mental illness in which irrational thoughts and fears cause one to perform repetitive actions (for example, excessive handwashing due to the fear of becoming contaminated by germs).

panic disorder (PD)

A disorder characterized by sudden, recurring attacks of intense anxiety and fear; includes physical symptoms that imitate a heart attack, as well as a general sense of loss of control.

paralysis

The temporary or permanent loss of voluntary movement (motor function).

paraplegia

A loss of voluntary movement (motor function) in the lower half of the body, including both legs; often as a result of spinal cord injury (SCI) or disease.

paresthesia

The sensation of numbness, prickling, or tingling, usually in the upper or lower extremities; caused by irritation of, or injury to, sensory nerves or nerve roots.

Parkinson’s disease (PD)

A progressive disorder of the nervous system marked by signs such as tremor, bradykinesia (slow movement), muscular rigidity, and an irregular gait.

petit mal seizure

Brief, sudden lapses of consciousness, most commonly characterized by vacant staring for 10 to 15 seconds; also known as an absence seizure.

phobia

An exaggerated fear of a specific object or situation that causes anxiety and panic.

poliomyelitis (polio)

Inflammation of the gray matter of the spinal cord; caused by a highly contagious virus.

post-traumatic stress disorder (PTSD)

A mental illness resulting from an extremely traumatic experience, illness, or injury that triggers persistent thoughts and memories of the experience.

postpartum psychosis

A rare psychiatric condition that develops within the first week after childbirth; characterized by confusion, disorientation, hallucinations, delusions, obsessive thoughts about the infant, paranoia, sleep disturbances, and/or attempts to harm the infant or self.

psychotic disorders

A group of mental illnesses characterized by loss of touch with reality, hallucinations, and delusions; also known as psychoses.

Reye’s syndrome

A rare but serious condition that results in acute encephalopathy (brain malfunction) and hepatomegaly (liver enlargement); typically seen in children under 18 years of age after a viral infection. Signs and symptoms include confusion, seizures, and loss of consciousness.

schizoaffective disorder

A chronic disorder in which a person experiences symptoms of both schizophrenia and symptoms of a mood disorder.

schizophrenia spectrum disorder

A mental illness that produces distorted thought processes and emotional perceptions; characterized by delusions, hallucinations, and/or periods of unresponsiveness.

seasonal affective disorder (SAD)

A form of depression that occurs during the fall and winter seasons as a result of less exposure to natural sunlight.

seizure

A disruption of electrical activity in the brain that produces physical and mental changes, such as convulsions, sensory disturbances, and loss of consciousness.

shingles

An eruption of a painful rash, often on the trunk (torso) of the body along a peripheral nerve; caused by the varicella-zoster virus (VZV), which also causes chickenpox.

social anxiety disorder

Anxiety disorder characterized by increased anxiety during social interactions.

somnambulism

Sleepwalking.

spina bifida

A condition in which part of the membrane covering the spinal cord protrudes through a gap in the spine; split spine.

subdural hematoma (SDH)

A mass of blood between the dura mater and the arachnoid mater of the brain; the most common type of traumatic brain injury (TBI).

substance-use disorders

Mental illnesses resulting from abusive use of substances such as drugs, alcohol, or toxins; characterized by social and personal dysfunction.

syncope

A temporary loss of consciousness due to inadequate blood flow to the brain; commonly known as fainting.

transient ischemic attack (TIA)

A brief stoppage of blood flow (ischemia) to a part of the brain; precursor to, or warning sign of, a stroke.

traumatic brain injury (TBI)

Injury as a result of a violent impact to the head.

tremor

An involuntary, repetitive trembling of the body or limbs.

unconsciousness

A lack of awareness of oneself and the inability to respond to environmental stimuli due to injury, shock, or oxygen deprivation.