A role for functional classification in the early identification of prognostic factors in ALS

The aim of this study was to determine if the interval between onset of symptoms to initial electrodiagnostic studies indicates disease progression in amyotrophic lateral sclerosis (ALS). Fifty consecutive patients referred to our neurophysiology laboratory with clinical evidence of ALS were divided into two groups by outcome scores on the ALS Functional Rating Scale (ALSFRS) using 26 as a cut-off. Our results, which showed a median of four months (range 2-24 months) duration to initial electrodiagnostics for Group I (ALSFRS scores below 26) versus 10 months (range 1-24 months) for Group II (p = 0.02), suggest this measure is a marker of disease progression in ALS.