There are various diseases like neurogenetic diseases such as Huntington’s disease and muscular dystrophy. Developmental disorders such as cerebral palsy. Degenerative diseases of adult life such as Parkinson’s disease and Alzheimer’s disease. Metabolic diseases such as Gaucher’s disease cerebrovascular diseases such as stroke and vascular dementia. Trauma such as spinal cord and head injury convulsive disorders such as epilepsy infectious diseases such as AIDS dementia and brain tumors etc.