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 criteri a for amyotrophic lateral sclerosis (ALS) classify patients into categories reflecting different levels of diagnostic certainty. We conducted a prospe ctive, 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 diagn ostic criteria. Methods: Using data from the Irish ALS Register, we studied the clinical fe atures 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 progressi on occurred over time: at last follow-up, 75% of all patients had bulbar si gns, compared with 59% at diagnosis. When the Fl Escorial criteria were app lied, more than half of patients (218 [56% ]) had definite or probable ALS at diagnosis. Of the 165 possible and suspected ALS cases at diagnosis (tri al 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 Hou se criteria had no effect on the median time from symptom onset to trial el igibility (12.9 vs 12.8 months). Conclusions: The El Escorial and Airlie House diagnostic criteria are exces sively restrictive. Furthermore, levels of diagnostic certainty cannot he u sed as prognostic indicators.