An actigraph is a portable device that measures movement, usually of the non-dominant wrist, to estimate rest-activity patterns and sleep-wake cycles. The use of actigraphy has grown over the past decade. Actigraphy has gained favor in the sleep community for the evaluation of insomnia and circadian rhythm disorders, and the device has become an important research tool. As sleep disorders are common in neurological patient populations, the use of actigraphy has increased in the clinical evaluation of neurological patients, particularly in patients with dementia, head trauma and autistic spectrum disorders. At the same time, actigraphy has grown as a clinical research instrument in neurological patient populations.