The effect of Heart Rate Variability Feedback to improve heart-brain function after spinal cord injury - The Spinal cord injury, Mind and HeART or (SMART) study

This study comprises a randomised controlled trial that involves the use of a neuro-cardiac self-regulation intervention (heart rate variability feedback, HRV-F). The trial consists of a parallel randomised two-arm controlled trial (HRV-F compared to a no treatment control) with up to 60 in each group, and assessed at baseline, immediate post HRV-F (i.e. approximately 10 weeks), and 6 and 12-month post baseline. Intervention protocol to be used in the trial involves HRV-F. HRV-F involves a participant’s heart rate variability and breathing delivered in a dynamic feedback form on standard laptops utilising specialised HRV feedback software (Procomp 2, Thought Technology Ltd; TGA approved: 119650). The goal is for the participant to learn to regulate their HRV and breathing patterns, called resonance frequency breathing, that is, slow relaxed diaphragmatic breathing around 3-7 breaths per minute that has a regulating effect on the autonomic nervous system, so that respiratory sinus arrhythmia and baroreflex gain are maximised. This is taught by training participants in slow breathing and supplying visual/auditory feedback of HRV activity related to their breathing. The HRV-F intervention protocol to be trialled consists of up to 10 training sessions over a period of at least 10 weeks. The ten training sessions will involve a mixture of face-to-face formal sessions (2 hours duration each) in the research lab as well as online/telephone sessions (at home sessions, up to 1-hour duration). Sessions will include: (1) introduction to HRV-F and slow breathing techniques (2) determination of participant’s resonance frequency breathing (3) HRV-F supervised practice, and (4) education about autonomic balance and health and transfer of HRV-F skills to everyday life and stressful contexts. Home-based training will involve daily homework related to the skills learned in the face-to-face formal HRV-F sessions in the clinic will be assigned and a diary used by participants to log homework activities. Homework activities will include: (1) tasks such as controlled and paced breathing as taught in the face-to face sessions (2) measuring HRV using HRV phone-based apps each day (3) psychological self-management strategies such as self-monitoring of mood, anxiety, breath/heart rate, pain/fatigue and sleep, and (4) visualisation strategies to enhance their self-regulation of HRV and breathing. A portable single finger sensor/chest strap (or a wristwatch) will be connected to the participant’s smartphone, with exportable biometric data measurement that will be sent to the research team after each session. These data will also be used to monitor adherence at home and elsewhere as applicable. Experienced health professionals trained in the strategies to be used will deliver training sessions. The homework activities and diary have been designed specifically for the RCT. Participants will be encouraged to apply the intervention skills as needed in their daily lives. Follow-up telephone sessions on a monthly basis will occur up to 12 months post entry into the trial, in which participants are rung by the research team and their progress discussed.