RESUMO
It is well known that the diagnostic process in amyotrophic lateral sclerosis (ALS) may be excessively prolonged, with negative consequences for the patients and their families. The ISIS study assessed the diagnostic process in 201 patients affected by ALS from 6 different countries (Argentina, Brazil, Germany, Italy, Spain and USA). The median time from onset to diagnosis ranged from 12 months in Spain to 17 months in Italy. The median time for patients to have a first consultation with a physician was 2 months (range: 1-1.5 months) and with a neurologist was 6-9 months. The median time needed for the neurologist to confirm the diagnosis was 3-6 months. Electromyography was performed on more than 90% of patients in all countries, and was requested in most cases by the neurologist. False-negative diagnoses were quite frequent (45% of cases with at least one other diagnosis evoked at any time before the ALS diagnosis) and were made by neurologists in 28% of cases, by general practitioners in 29% of cases, by orthopaedic surgeons in 26% of cases and by other specialists in 18% of cases. The reasons for misdiagnoses were: presence of other diseases to which the symptomatology was attributed, misinterpretation of examinations, and lack of familiarity with ALS.