Capturing patients' symptom expression and spouses' cardiovascular responses continuously: The feasibility of examining a mechanism of disease risk in the home

Introduction: Spousal caregivers face increased cardiovascular risks; lab studies suggest that autonomic reactivity to patients' physical suffering may play a role. To evaluate this mechanism in daily life, our pilot study characterized the feasibility of recruiting couples for a multimethod, in-home assessment. We examined the usability of the resulting data in an effort to link spousal cardiovascular changes to patient pain expression during couples' everyday interactions. Method: For two 48-hr periods, individuals with rheumatoid arthritis (RA) and their partners wore heart monitors while audio-recordings captured couples' in-home interactions. Interbeat intervals were subsetted in 1-, 2-, and 5-min windows before and after each pain expression. Pre-post difference scores in high-frequency heart rate variability (HF-HRV) and heart rate were examined. Results: Of the 17 screened RA patients, 11 were ineligible, and 3 partners declined. The 3 participating couples completed all study activities. The resulting 288 hr of recordings were coded for patients' RA symptom expression, which varied from none to an average of 11 times daily. One couple had sufficient data for physiological analysis: Contrary to prediction, spouse HF-HRV significantly increased after patient symptom expression. Conclusions: Recruitment rates mirrored other couples studies, and enrolled couples complied with study procedures. In-home conversations were reliably coded and successfully linked to spousal ongoing cardiovascular activity. Preliminary findings highlight the importance of optimal sampling windows and suggest symptom expression as a relevant process for some spouses but not others. We offer recommendations for efficiently scaling up the method in future studies.