RESUMO
OBJECTIVE: Interpersonal synchronization is increasingly studied as a biomarker of empathy, therapeutic alliance, and treatment outcome. However, most studies average data over sessions, leaving associations between synchrony and actual interactions largely unexplored. We aim to showcase a novel approach examining synchronization during specific micro-processes: Innovative Moments (IM) as markers of exceptions to clients' problematic patterns of meaning. METHODS: Electrodermal activity was recorded over 15 sessions of a psychodynamic psychotherapy single case. Moment-to-moment patient-therapist synchrony was calculated using the Adaptive Matching Interpolated Correlations (AMICo) algorithm. The Innovative Moments Coding System was utilized to identify IMs within session transcripts with precise timing. Monte-Carlo permutation tests were conducted to examine the association between physiological synchrony and IM Levels of increasing complexity (Levels 1-3). RESULTS: Higher-than-random synchronization emerged during Level 3 IMs (p = 0.046; d = 0.21) but not in lower Levels. Post-hoc qualitative analyses linked high synchrony to sub-processes of Level 3 IMs, such as positive contrasts and attributions for change. CONCLUSION: Our findings show it is possible to link moment-by-moment physiological co-regulation to theoretically identified meaning-making processes. While generalization of these observations is undue, this work demonstrates a robust and promising application of a multimodal approach to investigating psychotherapy, providing insights into both the clinical case and the theoretical model adopted.