We read with great interest the recent excellent article by Czaplinski et al1 concerning slower disease progression and prolonged survival with amyotrophic lateral sclerosis (ALS). The authors point out the possibility that the disease course has changed over time to be less aggressive.
We also analyzed the diagnostic interval and clinical course through hospital records for 147 patients with ALS between 1990 and 2005. Patients with ALS were divided into 2 groups. The historical group was defined as 117 patients diagnosed according to criteria from the World Federation of Neurology2 for definite or probable ALS up to 2000. The contemporary group consisted of 30 patients diagnosed by revised criteria3 for definite, probable, or “probable laboratory supported” ALS from 2001 to 2005. Despite the revised criteria, including electromyogram examination,3 our data suggested that the mean diagnostic interval in the contemporary group was longer, 13.3 months vs 12.3 months in the historical group. A similar pattern of diagnostic delay in patients of Czaplinski et al1 showed 12.9 months in the historical group and 14.2 months in the contemporary group. How do we explain the prolongation of diagnostic interval in contemporary patients? A delay in referring patients to neurologists may explain a possible cause. The rate of bulbar onset in our patients was 44% in the historical group and 29% in the contemporary group. Those results are similar to those found by Czaplinski et al1 for initial symptoms in bulbar muscles (20.1% in the historical group vs 10.7% in the contemporary group). Although bulbar ALS has a poor prognosis compared with limb-onset ALS, the authors indicate a slower progression in contemporary patients with a Cox proportional hazards multivariate model adjusted for age, sex, diagnostic delay, and site of onset.
Kano OI, Arasaki K, Ikeda K, Iwasaki Y. Slower Disease Progression and Prolonged Survival in Contemporary Patients With Amyotrophic Lateral Sclerosis. Arch Neurol. 2007;64(3):458-459. doi:10.1001/archneur.64.3.458-b