For functional abdominal pain, especially in children, biofeedback (heart-rate variability, hand warming, breathing) has produced good results in two small randomised trials and several clinical series: pain falls clearly, often within about ten sessions. For rumination syndrome, biofeedback-guided diaphragmatic breathing has become the reference treatment. Trials remain small, and the new studies since 2022 have not yet delivered the large trial that is needed.
AAPB2Possibly efficaciousNeuroLogic3Probably efficacioushigher vs AAPB
Level 3. AAPB holds Level 2 for want of randomised trials of HRV biofeedback, but its own base contains two randomised trials against a medical control in independent groups: Humphreys 2000 (n = 47 children with recurrent abdominal pain, three treatment arms including thermal biofeedback, all superior to fibre alone with no difference between them) and Schurman 2010 (n = 20, biofeedback-assisted relaxation added to standard medical care vs standard care alone in paediatric functional dyspepsia; clear improvement in the biofeedback arm, none in the medical arm). Added to these are the uncontrolled HRV series of Sowder 2010 (n = 20, large effect, pain reduction mediated by restored vagal tone) and Stern 2014 (clinical replication series, improvement in every patient) and, for rumination, Barba 2016's placebo-controlled trial (n = 23) of biofeedback-guided diaphragmatic breathing, now the treatment of choice (Halland 2018). AAPB rates the same paediatric literature Level 3; we align the two. The 2022-2026 window adds nothing decisive: Chakraborty 2026 (n = 85 adults with upper abdominal pain, consumer respiratory device vs written instructions, pain reduced in both arms with no between-group difference) and Pereira 2025's scoping review (four heterogeneous HRV studies, two positive, two null).
In short
Clinical reading
AAPB Level 2; NeuroLogic Level 3. AAPB holds Level 2 for want of randomised HRV-biofeedback trials, but it contains two randomised trials against a medical control in independent groups (Humphreys 2000, Schurman 2010), HRV series with mediation by vagal tone (Sowder 2010, Stern 2014) and a placebo-controlled trial for rumination (Barba 2016); AAPB rates the same paediatric literature Level 3. Functional abdominal pain is a functional gastrointestinal disorder; the label 'recurrent abdominal pain' is not a standardised diagnosis, which muddies the literature.
Protocols
Resonance-frequency HRV aimed at restoring vagal tone (Lehrer protocol, 6-10 sessions, daily practice), thermal biofeedback, multimodal assisted relaxation (EMG, temperature, EDA, respiration); for rumination, diaphragmatic breathing guided by abdominal EMG.
Limits
No stable diagnostic definition, small samples (20-47), unblinded ratings, variable outcome measures; no adequately powered randomised trial of HRV biofeedback; the only in-scope 2022-2026 trial rests on a consumer device; the adult literature outside rumination is thin.
Study base
Small literature: two randomised trials, two HRV series, one placebo-controlled rumination trial. 2022-2026 base: 29 publications indexed in the archive, 27 of which concern anorectal biofeedback (constipation, faecal incontinence), outside the AAPB rating's scope; 2 in scope (one trial, one scoping review).
Brendan's perspective
AAPB holds level 2 for want of randomised HRV trials, then lists two randomised trials against a medical control: Humphreys 2000 and Schurman 2010. AAPB already rates the same paediatric literature level 3. I have aligned the two, which is bookkeeping rather than enthusiasm. Sowder 2010 and Stern 2014 are uncontrolled series, but pain reduction mediated by restored vagal tone is the kind of mechanism I want to see stated out loud. For rumination, Barba 2016 makes biofeedback-guided diaphragmatic breathing the obvious first move. Referrals for abdominal pain are not common in my practice; when they arrive it is resonance-frequency HRV, six to ten sessions, and the daily home practice is where the result actually comes from. What the literature will not give you is scale: samples of twenty to forty-seven, unblinded child and parent report, no adequately powered trial. Tell the family this is a well-tolerated skill with modest, honest support, not a cure.
Sowder et al. (2010) Restoration of vagal tone: A possible mechanism for functional abdominal pain doi:10.1007/s10484-010-9128-8
Humphreys & Gevirtz (2000) Treatment of recurrent abdominal pain: Components analysis of four treatment protocols doi:10.1097/00005176-200007000-00011
Schurman et al. (2010) A pilot study to assess the efficacy of biofeedback-assisted relaxation training as an adjunct treatment for pediatric functional dyspepsia associated with duodenal eosinophilia doi:10.1093/jpepsy/jsq010
Stern, Guiles & Gevirtz (2014) HRV biofeedback for pediatric irritable bowel syndrome and functional abdominal pain: A clinical replication series doi:10.1007/s10484-014-9261-x
Pereira et al. (2025) The effects of heart rate variability biofeedback on functional gastrointestinal disorders: a scoping review doi:10.3389/fphys.2025.1511391
