Neurological disorders are diseases of the brain, spine and the nerves that connect them. Neurological damage is damage that's occurred to the nervous system, including the brain, spinal cord and nerves, whether through injury, infection or disease. This type of damage can cause problems with everything from moving and speaking to swallowing and breathing, as well as changes in memory, mood and sensory perception. The development of the human brain begins during pregnancy and continues through infancy, childhood and adolescence. Most brain cells are formed before birth but the trillions of connections between these nerve cells (neurons) are not developed until infancy. There are more than 600 diseases of the nervous system, such as brain tumors, epilepsy, Parkinson's disease and stroke as well as less familiar ones such as front temporal dementia. It is any disorder of the body nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakness, poor coordination, loss of sensation, seizures, confusion, pain and altered levels of consciousness. There are many recognized neurological disorders, some relatively common, but many rare. They may be assessed by neurological examination, and studied and treated within the specialities of neurology and clinical neuropsychology. Neurological disorders and their sequelae are currently estimated to affect as many as a billion people worldwide. These disorders are found among all age groups and in all geographical regions.For many of the neurological disorders there are inexpensive but effective interventions that could be applied on a large scale through primary care. Neurological disorders are wide ranging. They have various causes, complications and outcomes. Many result in additional needs requiring life-long management.