Single-subject Experimental Designs as a Useful Tool for Demonstrating Intervention Effects in Neurorehabilitation : Part 3. Interpretation of the Results and Recommendations

In neurorehabilitation research, each experimental design has inherent limitations, which means that not all aspects of this field can be validated against universal standards. Due to the unique needs of patients with neurological impairments, single-subject experimental design (SSED) is especially suited to neurorehabilitation studies. Thus, this study highlights the importance of reorienting experimental research methodologies in neurorehabilitation toward the extended application of SSED. While there is an ongoing debate on how best to analyze SSED data, visual analysis remains the standard approach. However, developing a scientific framework solely from visual data can limit the generalizability of findings. Recently, quantitative approaches, such as statistical analysis and clinical significance assessments for SSED data, have been introduced to improve the validity and reliability of findings. Furthermore, systematic reviews and meta-analyses that include well-conducted SSED studies have gained recognition as valuable methods for producing evidence on neurorehabilitation interventions, thereby enhancing the clinical relevance and applicability of SSED research. Therefore, high-quality SSED studies, alongside rigorous data collection methods, should be integrated into all neurorehabilitation-related fields. This study aims to advocate for quantitative approaches to enhance both interpretation of results and the practical application of SSED research in neurorehabilitation.