Alzheimer's) or voluntary motion (in movement disorders).
Cerebral palsy: a condition that affects muscle control and movement. It is usually caused by an injury or infection to the brain before, during, or after birth. It may also be due to lack or shortage of oxygen in the fetus brain, genetic problem, or other abnormal brain development. Children diagnosed with cerebral palsy often have difficulties in controlling muscles and movements as they grow and develop.
Cerebrovascular disease: the result of disease in the arteries and blood vessels in the brain which can cause blockage of food and oxygen supply to parts of the brain, leading to stroke.
Creutzfeldt–Jakob disease (CJD) (mad cow disease): a fatal neurodegenerative disease often with a lifetime of less than one year. Early symptoms include dementia, change of personality, and hallucinations [24]. The symptoms of CJD are caused by the progressive death of the brain's nerve cells, which is associated with the build-up of abnormal prion protein molecules forming amyloids [25].
Dementia (Alzheimer's, mild cognitive impairment): a worldwide problem which affects women more than men, and is the result of a number of brain diseases and abnormalities which lead to deterioration of memory, consciousness, and consequently physical disability and early death of the brain. It may also cause behavioural change, confusion and disorientation, delusion and hallucination, communication problems, problems in judging speed and distances, and even craving for particular foods. Alzheimer's is the most common dementia type but there are other dementias, including vascular dementia, dementia with Lewy bodies, and frontotemporal dementia. Research has shown that dementia causes loss of communication between brain cells and brain zones [17, 26].
Depression: a common mental disorder that causes people to experience depressed mood, loss of interest or pleasure, feelings of guilt or low self-worth, disturbed sleep or appetite, low energy, and poor concentration. It is different from feeling down or sad and affects people of every age. A person experiencing depression often has intense emotions of anxiety, hopelessness, negativity, and helplessness, and the feelings stay with them for a long time [24].
Encephalomyelitis: inflammation of the brain or spinal cord which can be the result of various diseases such as viral disease, mosquito bite, AIDS, or syndromes.
Encephalopathy: various brain disorders, and also reflects structural and anatomical defects in the brain.
Hydrocephalus: a condition in which there is an abnormal accumulation of cerebrospinal fluid in the brain [27]. This typically causes increased pressure inside the skull. Hydrocephalus can be due to birth defect or because of an injury in older age. In babies there may be a rapid increase in head size. Other symptoms may include vomiting, sleepiness, seizures, and downward pointing of the eyes. Older people may have headaches, double vision, poor balance, urinary incontinence, personality changes, or mental impairment.
Huntington's disease (after George Huntington 1872 – also known as Huntington's chorea): an inherited brain disorder which causes death of brain cells [28]. It starts with occasional mood swings or mental abilities [28]. It is followed with lack of coordination and unsteady movement [29]. As the disease advances, uncoordinated, jerky body movements become more apparent [28]. The physical abilities gradually worsen until movement coordination becomes severe and the person is unable to walk [28, 29]. Mental abilities generally decline into dementia [30]. The specific symptoms vary somewhat between people [28]. The disease symptoms usually begin between 30 and 50 years of age but can start at any age [30, 31].
Idiopathic intracranial hypertension: a neurological condition of unknown cause, with symptoms very similar to those of a brain tumour, defined by increased intracranial pressure around the brain without the presence of tumour or disease.
Meningitis: an inflammation of the meninges (the protective membranes that cover the brain and spinal cord) caused by an infection. The inflammation can cause damage to the brain and spinal cord. Acute bacterial meningitis is rapidly developing inflammation of the tissue layers and of the fluid-filled space between the meninges (subarachnoid space) when it is caused by bacteria.
Migraine: affects approximately 15% of the population. It is a primary headache disorder characterised by recurrent headaches mostly severe [32]. Typically, the headaches affect one side of the head, are pulsating in nature, and last for 2 to 72 hours [32]. The symptoms can be nausea, vomiting, and sensitivity to light, sound, or smell [33]. The pain is generally made worse by physical activity [34]. Up to one-third of people have an aura: typically a short period of visual disturbance which announces the onset of headache in advance [34]. Occasionally, an aura can occur with little or no headache after that [35]. Migraines are believed to be due to a mixture of environmental and genetic factors [36].
Multiple sclerosis (MS): a disease affecting or damaging the myelin which is the covering layer of nerve cells in the brain or spinal cord [37]. This damage disrupts communication between cells in the nervous system resulting in many signs and symptoms, including physical, mental, and sometimes psychiatric problems [38–40]. Double-vision, blindness of one eye, muscle weakness, trouble with sensation, and trouble with coordination are the specific symptoms [37]. MS is a degenerative disease and gradually goes to complexity. Brain MS is more severe. Although the actual cause is not clear, the underlying mechanism is thought to be either destruction of the immune system or failure of the myelin-producing cells.
Paralysis: the inability to move a part of the body temporarily or permanently. In almost all cases, paralysis is due to nerve damage, not to an injury to the affected region. Often an injury in the middle or lower regions of the spinal cord is likely to disrupt function below the injury, including the ability to move the feet or feel sensations, even though the actual structures are completely healthy. In this situation, the brain is unable to relay a signal to an area of the body due to injuries to the brain. However, in some cases the brain is able to sense touch and other sensations in the body, but is unable to effectively relay a response due to injuries in the spinal cord.
Parkinson's: a degenerative brain disorder. The cause is generally unknown but believed to be genetic or due to environmental factors [41]. Physiologically, the dopamine generators of the brain fail in generating sufficient dopamine as the result of death of cells in the substantia nigra in the midbrain region [42]. Diagnosis of typical cases is mainly based on symptoms such as tremor, rigidity, slowness of movement, difficulty in walking, dementia, depression, and anxiety.
Pick's disease: a rare form of dementia and similar to Alzheimer's, except that it often affects only certain brain zones. It has unknown causes and people with Pick's disease have abnormal substances (called Pick bodies and Pick cells) inside nerve cells in the damaged areas of the brain.
Seizure and epileptic seizure;: a temporary loss of control often, but not always, accompanied by convulsions, unconsciousness, or both. Most common types are epileptic seizures, or seizures, are caused by sudden abnormal electrical discharges in the brain. An epileptic seizure, also known as an epileptic fit, seizure, or fit, manifests itself in the form of a brief episode of signs or symptoms due to abnormal excessive or synchronous neuronal activity in the brain [43]. The outward effect can vary from uncontrolled jerking movement (tonic–clonic seizure) to something as subtle as a momentary loss of awareness (absence seizure). Diseases of the brain characterised by an enduring predisposition to generate epileptic seizures are collectively called epilepsy [44]. On the other hand, for nonepileptic seizures the brain activity remains normal. Nonepileptic seizures have no identifiable physical cause, but they are believed to be physical reactions to psychological stress, change of emotions, in some cases due to tumour in the brain, or as symptoms of hypertension.
Brain tumour: a growth of cells in the brain that multiplies in an abnormal, uncontrollable way. Brain tumours can be malignant, slow growing, or benign. The most common brain tumour is a glioma, which has different types including astrocytomas, glioblastomas, oligodendrogliomas, mixed gliomas, and ependymomas. Some grow slowly while others grow more quickly.
Meningioma: a common brain tumour. It starts in the meninges, the tissue covering the brain and spinal cord, and is usually benign. A lymphoma is a cancer of the lymphatic system. It rarely starts in the brain. An acoustic