Use of sequential medical trials in rehabilitation research

Although randomized, clinical trial designs represent the pinnacle of resea rch excellence, they are often difficult to implement in natural or clinica l settings. An alternative approach to analysis of data collected during re habilitation research is the sequential medical trial design. In a sequenti al medical trial, subjects are serially recruited and the results are conti nuously analyzed. The use of preconstructed sequential charts remove the ne ed for clinicians to perform complicated statistical analyses and allow an immediate visual indication of the direction the results are taking. Benefi ts of sequential medical trials are as follows: as soon as enough data are collected to show treatment preference, the trial is stopped; a trial that is showing no beneficial or even harmful effects can be quickly terminated; fewer subjects are needed (without loss of statistical power); features su ch as randomization, blinding, and cross-over designs can be included; the design suits the serial nature of rehabilitation practice. Limitations to s equential medical trials are that in simple designs extraneous factors cann ot be controlled for and that multiple dependent variables are difficult to assess. This article discusses the theory behind the sequential medical tr ial design and outlines how to plan a sequential medical trial, recruit sub jects, construct and use a simple sequential chart, and analyze and interpr et the results. Examples of sequential medical trials used in rehabilitatio n research are presented. It is hoped that this article will increase the e xposure of this useful design and result in greater use of sequential medic al trials by rehabilitation professionals.