For many neurologic disorders there are no national studies from which reliable prevalence estimates can be made. Without these estimates the impact of a given disorder may be unknown. Using data from the 1980 National Ambulatory Care Survey, of the US National Center for Health Statistics, estimates of the use of officebased physician services for individuals with transient ischemic attack, Parkinson's disease or epilepsy were made. There were 700,000 office visits for these disorders. The vast majority, over 60%, were to general practitioners and internists. After adjusting the general population data for visits to physicians specialising in obstetrics and gynaecology, differences in patient demographics, diagnostic services performed, and therapies initiated or continued were noted. Generally, given the nature of the conditions being studied, the differences were expected. Using data from the National Health Care Expenditures Survey, it is estimated that each of the study diseases, except for tests, treatments etc., cost the US society $21 million for office visits.