TABLE 1.

Neurodegenerative disease. Showing typical age of onset, symptoms and primary areas of central nervous system (CNS) involvement.

Disease	Typical age of onset	Global prevalence	Symptoms	Primary area of CNS effected
Alzheimer’s	∼65, but early onset <50	∼712 per 100,000	Episodic memory deficits, apathy and depression are early symptoms. Later symptoms include impaired communication, disorientation, confusion, poor judgment, behavior changes and, ultimately, difficulty speaking, swallowing and walking	Entorhinal cortex, hippocampus, cerebral cortex
Parkinson’s	∼60, but early onset <50	∼160 per 100,000	Bradykinesia, muscle rigidity, tremors, impaired posture and balance. Non-motor disturbances such as motivation and memory	Substantia nigra
Huntington’s	∼35	∼2.7 per 100,000	Progressive chorea, cognitive decline and psychiatric disorders.	Basal ganglia and cerebral cortex
Amyotrophic lateral sclerosis	∼65	∼2.2 per 100,000	Muscle weakness and progressive paralysis, respiratory insufficiency	Brain stem, spinal cord and primary motor cortex
Prion diseases	∼60	∼0.1–0.2 per 100,000	Loss of intellect and memory, personality changes, slurred speech, loss of balance/coordination, vision problems, abnormal jerking movements, progressive cognitive impairment and mobility	Cerebral cortex