Emotion regulation in prolonged grief disorder in later life: Protocol and rationale for a longitudinal neuroimaging study.

Bereavement is a near-universal experience in late life, yet only some older adults develop prolonged grief disorder (PGD). While most transition from acute grief (AG) to integrated (adaptive) grief, the neurobiological substrates underlying divergent trajectories are unclear. Emotion regulation dysfunction is hypothesized to play a central role in PGD pathogenesis, but longitudinal neuroimaging data in bereaved adults are lacking. This study aims to identify functional brain circuit measures of emotional regulation that predict pathological versus adaptive grief trajectories, aligning with the Research Domain Criteria (RDoc) framework for the Negative Valence System (Loss) construct. This single-site, 1-year longitudinal study aims to enroll 170 adults aged 50-89 years: 115 with AG and 55 age- and gender-equated non-bereaved participants. Participants will complete comprehensive psychiatric, neuropsychological, and psychosocial assessments, alongside neuroimaging both at study baseline and after 12 months. Functional neuroimaging includes resting-state fMRI, a face-shape matching task probing emotion processing, and a stop-signal task probing inhibitory control. Functional neuroimaging data are acquired using a harmonized Human Connectome Project protocol on a GE Signa Premier 3T MRI scanner. We present a comprehensive overview of the eligibility criteria, clinical study procedures, and neuroimaging protocol. Baseline findings from 103 AG and 40 non-bereaved participants thus far enrolled show that the groups are demographically matched and provide high-quality neuroimaging data and robust task performance. This study is among the first longitudinal neuroimaging investigations of AG in older adults and may identify early biomarkers of PGD risk, potentially guiding precision prevention and intervention strategies for bereaved older adults.