Introduction
Methods
Identification and selection of studies
Inclusion and exclusion criteria
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Participants: current smokers, smoking more than 10 tobacco cigarettes per day
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Intervention: biofeedback and/or neurofeedback
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Control groups: no training, sham or other training, non-smokers, no control group
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Outcomes: effects on smoking rates, smoking behavior, biofeedback/neurofeedback training measures
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Study design: prospective, controlled and uncontrolled studies
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Language limitations: published in English or German
Quality assessment
Results
Study selection
Risk of bias
Study | Downs and Black checklist items | Results | |||||||||||||||||||||||||||
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Reporting | External validity | Internal validity—bias | Internal validity—confounding (selection bias) | Power | |||||||||||||||||||||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | Total | Quality level | |
Pandria et al. 2018 [14] | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 21 | Good |
Bu et al. 2019 [15] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 0 | 23 | Good |
Griffith et al. 1983 [16] | 1 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 11 | Poor |
Intervention
Biofeedback studies
Study | Study sample | Study design Controls/comparators | Intervention/assessment | Results |
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Pandria et al. 2018 [14] | N = 27 (mean age: 50.52 ± 12.364 a, males:females = 9:18) | Pretest-posttest | BF: 5 skin temperature training sessions of 30 min. | ↓ Fagerström Test in males (p = 0.024) |
Median cig./d: 20 (r: 12.5–60) | No controls | Assessment: Baseline evaluation (session 1 and 2) and posttraining evaluation (sessions 3 and 4): clinical, behavioral, and electrophysiological evaluation | ↓ General Health Test in males (p = 0.031) | |
Mean smoking dependence: 358.5 ± 152.95 months | Questionnaires: Fagerström Test for Nicotine Dependence, Motivation, Contemplation Ladder, Minnesota Nicotine Withdrawal Scale, Beck Depression Inventory, State-Trait Anxiety Inventory, General Health Test, Rosenberg Self-Esteem Scale, World Health Organization Quality of Life-Brief | No change of CO levels after BF (p = 0.6) | ||
↓ Number of participants with moderate nicotine dependence decreased from 11 to 10 | ||||
↓ Number of participants with high nicotine dependence decreased 11 to 8 | ||||
EEG: Slight ↑ outflow of left vlPFC (p = 0.065), slight ↑ outflow of right TPC (p = 0.059) | ||||
Females: ↑ outflow of right TPC (p = 0.028) | ||||
Males: left mPFC (p = 0.003) and left PCU (p = 0.005) | ||||
Reduced daily cigarettes: not reported | ||||
Ratio of smokers who quit: not reported | ||||
Bu et al. 2019 [15] | N = 60 (age: 18–40a, males) | RCT | NFB: 2 training sessions of 1 h, interval: 1–2 days | Effects on event-related potential correlates of cigarette craving: |
Cig./d: > 10 for 2 years or more | Real-NFB group (n = 28) vs. yoked-NFB group (n = 25): brain activity pattern of matched participants | No smoking 2 h prior to training sessions | Real-NFB group: ↓ in craving-related P300 amplitudes compared with the yoked-NFB group (group-time interaction effect: p = 0.028) | |
Visit 1: Baseline evaluation: clinical and behavioral assessment (TCQ, craving-related P300) | Short-term effects on cigarette craving: | |||
Visit 2 + 3: 2 NFB training sessions: smoking cue reactivity task (smoking-related images and neutral images) | Craving (TCQ): real-NFB group ↓ craving score from pre-NFB to post-NFB (p = 0.00021) | |||
Visit 4: Post-training behavioral session | Long-term effects on smoking behavior: | |||
Visit 5: Follow-up session | Real-NFB group: ↓ cig./day compared to the yoked-NFG | |||
Assessment: P300 pre-NFB and post-NFB | ↓ cig./d at follow-up: 1 week (30.6%), 1 month (38.2%), 4 months (27.4%) | |||
TCQ: Cig. craving at pre-NFB (before 1. training session) and post-NFB (after 2. training session) | Yoked-NFB group: ↓ cig./d at follow-up: 1 week (14%), 1 month (13.7%), 4 months (5.9%) | |||
Interview: cig./day | Group differences were significant at 1 week (p = 0.01), 1 month (p < 0.005), 4 month (p = 0.03) | |||
Cig./d at baseline, 1 week, 1 month, 4 months after final neurofeedback visit | Ratio of smokers who quit: not reported | |||
Griffith and Crossman 1983 [16] | N = 6 (age: not reported, males) | Pretest-Posttest | NFB, 8 daily 30 min sessions: | During smoking a cig.: ↑ 4–8 Hz activity (n = 4) |
Moderate or heavy smokers (16–24 or > 35 cig./d) | No controls | No smoking 1 h prior toNFB | ↓ 8–12 Hz activity (n = 6), ↑ HR (n = 5) | |
Phases: | Immediately after smoking a cig.: no consistent brain wave change, ↑ HR (n = 5), ↓ skin temperature (n = 4) | |||
A1: Baseline | NFB: ↑ time spent producing 8–12 Hz compared to baseline levels (n = 4) | |||
B: Smoking a cigarette | Fadeout: participants (n = 2) able to produce 8–12 Hz activity levels for higher percentage of time without audible feedback at the end of the fadeout phase had quitted smoking at 6‑month follow-up, the other participants reduced daily cigarettes to 12–61% (n = 4) | |||
A2: Baseline | ||||
C: NFB: learn to produce occipital 8–12 Hz (alpha waves) in EEG, music feedback, eyes open | ||||
D: Fadeout: training to produce 8–12 Hz without audible feedback over 8 sessions | ||||
Assessment: | ||||
Occipital EEG, HR, hand skin temperature, blood pressure, behavioral data (Smoker’s Self-Testing Kit, General Background Questionnaire, smoking frequency inside and outside the experimental setting) |