Effects of Biofeedback in Patients With Acute Cerebral Infarction

Study protocol Participants who provided signed consent were randomly assigned to HRVBF intervention or control group. They underwent baseline measurements of demographics, psychological distress, cognitive impairment, ADL capabilities, and autonomic function. Random numbers from the Bernoulli distribution were calculated using the Excel BINOMDIST function, and concealed in an opaque envelope, until participants' baseline measurements were completed. The HRVBF group received four, one-on-one bedside biofeedback training sessions (20-minutes a day for 4 days), and practiced on their own (10-minutes twice a day) using a FDA-regulated, hand-held mobile biofeedback device (StressEraser, Helico Inc., New York, NY, USA).26 The control group received usual care. Afterwards, all participants were telephoned bi-weekly and encouraged to practice slow breathing (HRVBF group) or to perform self-care (control group) for three months. psychological distress, cognitive impairment, ADL capabilities, and autonomic function (represented by HRV) were re-assessed at one, and 3-months after the intervention, by an independent investigator blinded to group assignment. HRVBF intervention protocol The HRVBF protocol was modified from Lehrer's HRV biofeedback manual.20 A noninvasive visual biofeedback system (NeXus-10 with BioTrace+, Mind Media B.V., Netherlands) and a laptop computer were used for the intervention. Participants in the HRVBF group received four, one-on-one bedside training sessions (20-minutes a day for 4 days). The first session (Day 1) was focused on teaching patients to breath slowly (6-8 breaths-per-minute) and to extend their expiratory phase using pursed-lip breathing. Also, respiration sensors for tracking breathing pace were introduced. The second session (day 2) was focused on teaching patients diaphragmatic breathing in conjunction with pursed-lip breathing, and to use respiratory sensors to pace breathing (6 breaths a minute). The third and fourth sessions (days 3 and 4) were focused on reviewing diaphragmatic breathing, pursed-lip breathing, and teaching patients to breathe in-phase with their heart rate changes. Additionally, participants were encouraged to practice slow diaphragmatic and pursed-lip breathing, on their own, with the aid of the hand-held biofeedback device, for 10 minutes, twice-a-day, during the 4-day training period.