Evaluating an intervention to increase meaningful activity after severe traumatic brain injury: A single-case experimental design with direct inter-subject and systematic replications.

Severe traumatic brain injury (sTBI) often results in significant morbidity, with fewer than 50% returning to work and only a minority resuming leisure and social activity. Yet few effective interventions are available for non-vocational activity. The aim of the study was to develop a new goal-directed intervention, the Programme for Engagement, Participation and Activities (PEPA), and evaluate its effect. The research design was a multiple-baseline design across behaviours, with direct inter-subject and systematic replications. Seven participants with sTBI, neurobehavioural impairment including apathy, inability to work, and limited leisure/social activities were categorised into two groups. Group 1 (n = 4) had cognitive impairments but were functionally independent. Systematic replication was conducted in a further three participants (group 2) with major neurobehavioural impairments and functional disability. Generalisation measures evaluated other life domains in group 1 participants (e.g., mood, community participation). Results of the weighted average Tau-U across the tiers was significant for six out of seven participants, with large effect sizes (≥.64) for five participants. Generalisation effects extended to other domains of life. The PEPA thus shows promise as an effective intervention to increase non-vocational activity and improve mental health outcomes in people with neurobehavioural disability after sTBI. These results add to the evidence for the effectiveness of goal-directed interventions.

Revision of a method quality rating scale for single-case experimental designs and n-of-1 trials: the 15-item Risk of Bias in N-of-1 Trials (RoBiNT) Scale.

Recent literature suggests a revival of interest in single-case methodology (e.g., the randomised n-of-1 trial is now considered Level 1 evidence for treatment decision purposes by the Oxford Centre for Evidence-Based Medicine). Consequently, the availability of tools to critically appraise single-case reports is of great importance. We report on a major revision of our method quality instrument, the Single-Case Experimental Design Scale. Three changes resulted in a radically revised instrument, now entitled the Risk of Bias in N-of-1 Trials (RoBiNT) Scale: (i) item content was revised and increased to 15 items, (ii) two subscales were developed for internal validity (IV; 7 items) and external validity and interpretation (EVI; 8 items), and (iii) the scoring system was changed from a 2-point to 3-point scale to accommodate currently accepted standards. Psychometric evaluation indicated that the RoBiNT Scale showed evidence of construct (discriminative) validity. Inter-rater reliability was excellent, for pairs of both experienced and trained novice raters. Intraclass correlation coefficients of summary scores for individual (experienced) raters: ICC(TotalScore) = .90, ICC(IVSubscale) = .88, ICC(EVISubscale) = .87; individual (novice) raters: ICC(TotalScore)= .88, ICC(IVSubscale) = .87, ICC(EVISubscale) = .93; consensus ratings between experienced and novice raters (ICC(TotalScore) = .95, ICC(IVSubscale) = .93, ICC(EVISubscale) = .93. The RoBiNT Scale thus shows sound psychometric properties and provides a comprehensive yet efficient examination of important features of single-case methodology.