[Use of the "N of 1" method for determining therapeutic choice: first experiences]

The "N of 1" study is a randomized, placebo-controlled, cross over study of a single drug in a single patient, which can be particularly useful when physicians are faced with chronic, stable diseases and/or complex treatments. We applied this model in 2 patients with neurological disorders. In the first case (a movement disorder) the N of 1 trial allowed us (and the patient!) to conclude that only one drug was really needed to control the disease. In the second case (a painful neuropathy) we could avoid using a potentially useful, but toxic drug, which turned out to be no more effective than placebo. We suggest that the "N of 1" trial model should be frequently applied in general as in well as in neurological practice.