THE NATURAL-HISTORY OF AMYOTROPHIC-LATERAL-SCLEROSIS

Using 42 strength and functional assessments recorded monthly, the nat ural history of amyotrophic lateral sclerosis (ALS) is described in 16 7 patients (98 men, 67 women) followed in five medical centers in the western United States. The mean age at onset was 57.4 years, and sympt oms were present for 2.64 years before study entry. Although there was a highly variable rate of decline within the group of patients, there were no differences in rate of decline by age or gender. Older patien ts and women were weaker on entry. Forty-eight patients died during th e study. The median survival was 4.0 years for the study cohort but 2. 1 years for newly diagnosed cases. Decline in pulmonary function most closely correlated with death. Our results emphasize the importance of considering clinical variability in planning clinical trials. One pos sible strategy is to identify and stratify patients by rate of decline in pulmonary function since prospectively identifying homogeneous sub groups allows investigators to substantially reduce sample size in the rapeutic trials.