Single-Subject Design: Experimental Designs for Research and for Clinical Practice

Background: The individual variability among people presenting motor impairments often leads to the difficulty to obtain an adequate sample size in the conduction of trials in physiotherapy. Furthermore, in clinical practice, it is often difficult to recognize the relationship between the administration of a treatment and its expected results. Psychological and educational sciences often use single-subject design (SSD) studies to explore behaviours under experimental conditions. This study design allows to test the relationship between an independent variable, the treatment, and a dependent variable, the main outcome of interest. The purpose of this work is to present researchers and clinicians the methodology of the SSD studies and their application in physiotherapy both in research context and everyday practice [1].