Advanced Regression Methods for Single-Case Designs: Studying Propranolol in the Treatment for Agitation Associated With Traumatic Brain Injury

Objective: The use of single-case designs in intervention research is discussed. Regression methods for analyzing data from these designs are considered, and an innovative use of logistic regression to analyze data from a double-blind, randomized clinical trial of propranolol for agitation among persons with traumatic brain injury (TBI) is used. Method: Double-blind, randomized clinical trial performed in an outpatient rehabilitation setting. Participants: Nine men and 4 women with TBI. Results: Logistic models indicated that propranolol was not associated with less agitation for most participants (Φ = .135; 90% exact confidence interval was −.03 < .135 < .29). Four participants displayed a significant response to propanolol. Two participants demonstrated significant improvement, and the other 2 experienced significantly more agitation in the treatment phase. Summary: Advanced regression methods can be used to analyze data from single-case designs to obtain information of clinical and statistical significance from a variety of psychological and medical treatments.