The natural history of drop attacks.

We grouped 108 patients with drop attacks, according to potential mechanisms based on predominant associated medical conditions, as follows: unknown, 69 (64%); cardiac, 13 (12%); cerebrovascular insufficiency, 9 (8%); combined cardiac and cerebrovascular disease, 8 (7%); seizures, 5 (5%); vestibular, 3 (3%); and psychogenic, 1 (1%). Fifty-four percent of the patients received no treatment, but similar percentages of treated (82%) and untreated (84%) patients were symptom-free at follow-up. The stroke rate in the overall group, approximately 0.5% per year, was not significantly different from that in a normal age- and sex-matched population. The favorable long-term outcome in drop attack patients with unrevealing medical and neurologic workups suggests that treatment is unwarranted for an isolated drop attack.