In the second phase of this epidemiological survey, a board-certified sleep neurologist (P.R.C.) will provisionally move to Atahualpa to examine all persons who screened as suspected cases of having a sleep disorder (in one or more of the field instruments used). In addition, a random sample of 2% of individuals who were considered negative during the screening phase (matched by age and gender to suspected cases) will also undergo a specialized examination to assess possible false negative cases during the survey. Neurologists will be blinded as to whether the individual was positive or negative during the screening phase. All these persons will be evaluated with a unified sleep history focusing on sleep-related symptoms, associated nocturnal symptoms, time during the sleep period that symptoms occur, daytime functioning, sleep schedule, and the use of sleep medications; in addition, a complete physical and neurological examination will be performed. For persons with suspected restless legs syndrome, questions will be directed to assess frequency and severity of symptoms, age of symptoms onset, and family history of restless legs syndrome. In additions, mimics of this condition will be ruled out (leg cramps, positional discomfort, fibromyalgia, arthritis, neuropathies, claudication, etc).