Clinical features of amyotrophic lateral sclerosis according to the El Escorial and Airlie House diagnostic criteria -: A population-based study

Background: The El Escorial and the revised Airlie House diagnostic criteria for amyotrophic lateral sclerosis (ALS) classify patients into categories reflecting different levels of diagnostic certainty. We conducted a prospective, population-based study of the natural course of ALS in the Republic of ireland during a 6-year period to examine the utility of these ALS diagnostic criteria. Methods: Using data from the Irish ALS Register, we studied the clinical features of all patients diagnosed as having ALS in Ireland throughout their illness. Results: Between 1993 and 1998, 388 patients were diagnosed as having ALS. Forty percent of patients reported bulbar-onset symptoms. Disease progression occurred over time: at last follow-up, 75% of all patients had bulbar signs, compared with 59% at diagnosis. When the Fl Escorial criteria were applied, more than half of patients (218 [56% ]) had definite or probable ALS at diagnosis. Of the 165 possible and suspected ALS cases at diagnosis (trial ineligible), 110 (67%) were trial eligible at last follow-up. Of the 254 patients who had died, 229 (90%) had definite or probable ALS, whereas 25 patients (10%) remained trial ineligible at death. El Escorial category at diagnosis was not a significant prognostic indicator. Use of the Airlie House criteria had no effect on the median time from symptom onset to trial eligibility (12.9 vs 12.8 months). Conclusions: The El Escorial and Airlie House diagnostic criteria are excessively restrictive. Furthermore, levels of diagnostic certainty cannot he used as prognostic indicators.