Categorization Program Effectiveness and Influential Factors: A Retrospective Multiple Case Study

Research Objectives: 1. To evaluate the effectiveness of the Categorization Program (CP) in enhancing cognitive functions among patients with moderate-severe TBI at the chronic phase of recovery.
2. To assess the impact of single nucleotide polymorphisms and polygenic risk score (PRS), on cognitive rehabilitation outcomes in TBI patients.
2. To investigate the relationship between demographic and clinical factors and cognitive recovery post-TBI.

Design: This retrospective multiple case study utilized data from the Brain Rehab Project, focusing on moderate to severe TBI patients. A case-by-case analysis was performed, constructing narratives for each participant. Following this, a cross-case analysis was conducted, systematically comparing and contrasting these individual narratives to identify common themes, differences, and patterns among the cases. This comparative analysis helped to enhance our understanding of the intervention's efficacy, highlighting which elements have an impact on recovery.

Setting: The setting included multiple sources: acute injury data from Nicosia General Hospital's ICU, genetic data from Biobank Cyprus, and cognitive assessments within a controlled research environment (pre- and post-intervention). The CP was administered using a hybrid model with in person and online sessions allowing for a flexible yet structured rehabilitation process.

Participants: Eight adult participants (aged 18-64) diagnosed with moderate to severe TBI at least one year prior to the study were selected. Exclusion criteria encompassed pre-existing CNS disorders, learning disabilities, significant psychiatric disorders, active substance abuse, and non-native Greek speakers.

Interventions: The CP conducted over 12-16 weeks with two sessions per week.

Main Outcome Measures: - Global Outcome (Glasgow Outcome Scale-Extended)
- Verbal Memory (Auditory Verbal Learning Test and Logical Memory Test)
- Visual Memory (Rey Complex Figure Test)
- Executive Functioning (Trail Making Tests, Digit Span, Visual Span)
- Verbal Fluency and Retrieval (Verbal Fluency Test)
- Emotional Function (Beck Depression Inventory-II)

Results: - Younger age at injury, and higher educational level were significant predictors of better cognitive recovery across various domains.
- APOE polymorphism (rs429358) correlated with poorer verbal memory outcomes.
- The CP was effective in improving cognitive functions in all participants. However, there was variability in the outcomes influenced by genetic, clinical, and demographic factors.

Conclusions: The study underscores the complex interplay between genetic, demographic, and clinical factors in cognitive recovery post-TBI. It highlights the potential of targeted cognitive rehabilitation programs, like the CP, in facilitating significant improvements in cognitive functions among TBI patients, emphasizing the need for personalized rehabilitation strategies.

Author(s) Disclosures: The authors declare no conflicts of interest related to this study.