Heart Rate Variability Biofeedback for Smoking Cessation

Satisfaction and liking were assessed via self-report ratings on five items assessing satisfaction with learning the intervention, liking the intervention, breathing techniques, nicotine replacement, and recommending the intervention to friends, rated on a 0=completely disagree to 4=completely agree Likert-type scale. Higher scores on this scale are indicative of greater intervention acceptability. Mean scores obtained following the first intervention session and 3-month follow-up session are reported.

Time frame: Week 1 (i.e., treatment initiation) and Week 16 (i.e., 3-month follow-up)

Population: Of the N=10 participants who were enrolled in the study, n=9 completed this measure following their baseline appointment; n=3 attended their 3-month follow-up and provided complete data for this measure.

Number of intervention sessions attended out of 10 possible sessions.

Time frame: 7 weeks

Population: Data on both the Intent-to-treat (ITT) N=10 participants who completed the baseline session and were enrolled in the study and the n=7 who received more than one Heart Rate Variability Biofeedback Session (HRVB) and one Smoking Cessation Treatment (SCT) session (i.e. which occurred during their first intervention appointment) are reported.

Appropriateness was assessed via self-report ratings on two items assessing the intervention in terms of comprehension and fit, rated on a 0=completely disagree to 4=completely agree Likert-type scale. Higher scores on this scale are indicative of greater perceived intervention appropriateness. Mean scores obtained following the first intervention session and 3-month follow-up session are reported.

Time frame: Week 1 (i.e., treatment initiation) and Week 16 (i.e., 3-month follow-up)

Population: Of the N=10 participants who were enrolled in the study, n=9 completed this measure following their baseline appointment; n=4 attended their 3-month follow-up.

Ease of the Intervention was assessed via self-report ratings on three items assessing ease of use and fit into daily lifestyle, rated on a 0=completely disagree to 4=completely agree Likert-type scale. Higher scores on this scale are indicative of greater perceived ease of the intervention and fit into daily lifestyle. Mean scores obtained following the first intervention session and 3-month follow-up session are reported.

Time frame: Week 1 (i.e., treatment initiation) and Week 16 (i.e., 3-month follow-up)

Population: Of the N=10 participants who were enrolled in the study, n=9 completed this measure following their baseline appointment; n=4 attended their 3-month follow-up.

Effectiveness was assessed via self-report ratings on four items assessing the intervention in terms of helping them quit and manage emotional distress, rated on a 0=completely disagree to 4=completely agree Likert-type scale. Higher scores on this scale are indicative of greater perceived intervention efficacy. Mean scores obtained following the first intervention session and 3-month follow-up session are reported.

Time frame: Week 1 (i.e., treatment initiation) and Week 16 (i.e., 3-month follow-up)

Population: Of the N=10 participants who were enrolled in the study, n=9 completed this measure following their baseline appointment; n=4 attended their 3-month follow-up.

Self-reported change in emotional distress was evaluated via the 21-item, Depression, Anxiety and Stress Scale (DASS-21). The DASS-21 is composed of three self-report scales that measure the emotional states of depression, anxiety and stress. Items are rated on a Likert-type scale (0=Did not apply to me at all, to 3=Applied to me very much, or most of the time). Scores for depression, anxiety and stress are calculated by summing the scores for the relevant items. The severity ratings are as follows Depression: Normal 0-4, Mild: 5-6, Moderate: 7-10, Severe: 11-13, Extremely Severe: 14-21. Stress: Normal: 0-7, Mild: 8-9, Moderate: 10-12, Severe: 13-16, Extremely Severe: 17-21. Anxiety: Normal: 0-3, Mild: 4-5, Moderate: 6-7, Severe: 8-9, Extremely Severe: 10-21. Total scores are computed by summing the subscales. Total scores for the DASS-21 range from 0-63. For all scales, higher scores are indicative of greater emotional distress and less change in total distress symptoms over time.

Time frame: Week 0 (i.e., baseline), Week 5 (i.e., 2-weeks post-quit), Week 7 (i.e., 1-month post-quit) and Week 16 (i.e., 3-month follow-up)

Population: Of the N=10 participants who were eligible and attended their baseline session, n=6 attended their 2-weeks post-quit session, n=5 attended their 1-month post-quit session, n=4 attended 3-month follow-up session.

Cigarettes Smoked Per Day (CPD) assessed via the well established Timeline Followback calendar interview were used to measure changes in smoking behavior from Week 0 (i.e., Baseline) through Week 3 (i.e., Quit date) and Week 16 (i.e., 3-month follow-up).

Time frame: Week 0 (i.e., baseline), Week 3 (i.e., Quit Date) and Week 16 (i.e., 3-month follow-up)

Population: Of the N=10 participants who were eligible and attended the baseline session, n=7 attended their quit date and n=4 attended their 3-month follow-up session

Quit status was assessed on Quit day via self-reported abstinence and carbon monoxide analysis of breath sample (CO \<8 ppm). Given carbon monoxide analysis of breath may not be a valid indicator of cessation within the first 24 hours, we suggest interpretation of this outcome on Quit day with caution. Sustained smoking cessation was evaluated at study termination (i.e., 3-month follow-up) via self-reported abstinence, carbon monoxide analysis ( CO \<8 ppm), and salivary cotinine (\<10 ng/mL).

Time frame: Week 3 (i.e., Quit Date) and Week 16 (i.e., 3-month follow-up)

Population: Of the N=9 who were eligible and initiated treatment, n=7 attended their quit date and n=4 attended their 3-month follow-up.