Functional outcome measures as clinical trial endpoints in ALS.

The topiramate study was a 12-month randomized placebo-controlled trial in patients with ALS. Follow-up evaluation of the placebo group (n = 97) constituted a well-described cohort of patients with ALS, in whom multiple outcome measures were assessed at 3-month intervals. During the 12-month study period, the decline of forced vital capacity (FVC%) and ALS functional rating scale (ALSFRS) was linear, whereas the decline of maximum voluntary isometric contraction-arm (MVIC-arm) and MVIC-grip Z scores was curvilinear. Rates of FVC% and ALFRS decline, but not of MVIC-arm or MVIC-grip, were independent predictors of survival.