FIG. 1.

Trends over time of key spinal cord injury (SCI) trial features in ClinicalTrials.gov. (A) The number of SCI trials has increased rapidly since 2000, particularly for drugs and novel intervention types including behavioral treatments. (B) Average trial enrollment (dashed line) has shown a recent increase after holding steady since 2000, while average trial duration (solid line) has fallen steadily. (C) Since 2002, there have been increases in the numbers of Phase I (Ph I), II (Ph II), and IV (Ph IV) trials, relative to Phase III (Ph II) trials. Proportions that do not total 100% exclude Phase 0 trials. (D) The age group distributions in clinical trials have consistently emphasized studies of adults and seniors. Proportions that do not total 100% exclude child-only trials.