Development of a next day functioning measure to assess the impact of sleep disturbance due to restless legs syndrome: the restless legs syndrome-next day impact questionnaire.

Objectives: Symptoms of Restless Legs Syndrome (RLS) affect patients' quality and duration of sleep, which can have next day sequelae detrimental to daytime performance. To date, no measure sufficiently assesses such sequelae. This study aimed to develop a new self-reported outcome measure to assess the impact of disturbed sleep due to RLS on next day functioning and to support its content validity.