Table 1.

Summary of reviewed studies.

Author(s) Country	Neuromodulatory Treatment/Study Design	Group and Intervention Description	Sample Description	Assessment Points and Outcome/Process Variables	Summary of Key Findings
Siniatchkin et al. [37]   Germany	NF   Non-randomized pilot study	Groups   G1: NF treatment G2: Healthy controls G3: Waiting list   Session details   Number of sessions: 1 introductory session + 10 training sessions over 8 weeks.   Session content: -20 trials of baseline CNV recordings (reaction time paradigm), 10′ training/5′ break -30 trials of increasing SCP negativity, 15′ training/5′ break -30 trials of suppressing SCP negativity 15′ training/5′ break -15 transfer trials of increasing SCP negativity 7′ training/3′ break -15 transfer trials of suppressing SCP negativity 7′ training/3′ break	G1: n = 10 80% male Mean age = 10.5 years Dx.: Migraine without aura   G2: n = 10 70% male Mean age = 11.6 years Dx.: Healthy children   G3: n = 10 80% male Mean age = 9.9 years Dx.: Migraine without aura	Assessment points -Baseline -Post-treatment -6-month follow-up   Outcome variables -Average number of days with migraine -Duration of migraine episodes -Headache intensity -Accompanying symptoms (i.e., nausea/vomiting) -Medication intake -Amplitude of the SCPs	50% of the treatment group presented a 50% or greater reduction in the number of migraines a month after treatment. Migraine duration reductions were observed in treatment and waiting list groups. No significant changes in the waiting list group in accompanying symptoms (nausea, vomiting, intensity of migraine, or medication intake). No significant differences between the treatment group and the waiting list group in medication intake and migraine intensity. Successful suppression of SCPs’ amplitude in the treatment group.
Stokes & Lappin [38]   USA	NF   Case series	One group only   NF + pirHEG + medication   Session details   Number of sessions: 40 sessions (30 NF + 10 pirHEG/thermal feedback) Session content: -2 channels NF -Individualized protocols -5 electrode placement: T3 I T4, C3 I C4, F3 I F4, FP1 I FP2, P3 I P4 -Auditory or visual feedback	n = 13 70% female Mean age = 13.4 years Age range = 9–21 years Dx.: Migraine	Assessment points -Baseline -Follow-up (variable: from 3 months to 2 years)   Outcome variable -Average number of days with migraine	Significant decreases observed in the average number of migraine days from pre-treatment to follow-up.
Gauntlett-Gilbert et al. [53]   United Kingdom	Meditation   Case series	One group only   ACT residential pain management program   Session details   Sessions duration: 90 h over 3 weeks Session content: -Three components: physical conditioning, activity management, and psychology - Psychology topics included: - Acceptance - Defusion - Present moment contact - Values - Committed action - Self-as-context	n = 98 75% female Mean age = 15.6 years Age range = 10.8–19.0 years Dx.: Idiopathic pain, complex regional pain syndrome, back pain, abdominal pain, pain associated with hypermobility	Assessment points -Pre-treatment -Post-treatment -3-month follow-up   Outcome variables -Physical disability -Social disability -Walk distance -Sit to stand -Pain intensity -Depression -Pain-specific anxiety -Perceived psychosocial development -Pain catastrophizing -Acceptance of pain -School attendance -Number of medications -Health care use	Significant pre- to post-treatment improvements observed in physical and social disability, walking distance, pain anxiety, pain catastrophizing, pain acceptance, school attendance and medication use that were maintained at follow-up. Significant pre- to post-treatment improvements in depression and perceived psychosocial development were observed, but these improvements were not maintained at follow-up. Significant pre- to follow up decrease in health care use. No significant differences in pain intensity at post-treatment and follow-up.
Hesse et al. [50]   USA	Meditation   Case series	One group only   MBSR   Session details   Number of sessions: 8 weekly sessions Session duration: 2 h Session content: -Homework and incentives -Welcoming and centering practice: awareness and mindfulness sound -“Food for thought”: relations of quotes or poems with their experiences -Didactic lessons: awareness of breath, heartfulness, and body scan guided meditations -Learned mindful listening, eating, and walking -Discussion of home practice -Closing mindfulness practice -Journaling prompts -Home practice -Guided meditation once per day -Daily diaries	n = 20 100% female Mean age = 14.15 years Age range = 11–16 years Dx.: Headache	Assessment points -Pre-treatment -Post-treatment   Process variables -Average number of sessions attended -Average of adherence to daily meditation -Completion rate -Helpfulness of the intervention -Perceived effect of the intervention to headache   Outcome variables -Frequency and severity of headache -Pain interference -Headache disability -Quality of life (physical, emotional, social, and school function) -Pain acceptance: activity engagement and pain willingness -Depression -Anxiety	Average number of sessions attended: 6.10 of 8 total sessions. Average of adherence to daily meditation practice: 4.69 of 6 practices per week. Number (%) who completed treatment: 15 (75%). 53% reported the treatment was helpful in coping with stress, relaxing and controlling their emotions and pain; 40% reported that it was helpful in specific ways (i.e., pain reduction); 13% reported the intervention was not as helpful as expected. 33% reported the intervention not affect their headache, 20% reported having fewer headaches, 13.3% reported having less severe headache, and 7% the headache got better. Significant pre- to post-treatment improvements were observed in depressive symptoms and pain willingness. No significant pre- to post-treatment differences were observed in frequency and severity of headache, disability, quality of life, anxiety, or activity engagement.
Jastrowski et al. [51]   USA	Meditation   Randomized pilot (i.e., very small sample size) study	Groups   G1: MBSR G2: Psycho-educational group   Session details   Number of sessions: 6 weekly sessions Session duration: 90’ Session content:   G1: -Body awareness -Basic yoga -Relaxation techniques -Body-scan meditation -Walking meditation -Appreciation of the self and respect for uniqueness -Non-judgment of thoughts -Gratitude meditation -30 min homework 6 days/week.   G2: -Cognitive-behavioral model of chronic pain (anatomy-physiology and misconceptions about pain) -Stress management -Communications skills	G1: N = 4 75% female Mean age = 15.0 years Age range = 12–17 year. Dx.: Chest pain, extremity pain, headache pain, back pain   G2: N = 2 100% female Mean age = 12.5 years Age range = 12–13 years Dx.: Abdominal pain	Assessment points -Pre-treatment -Post-treatment -4-week follow-up -12-week follow-up   Process variables -Group attendance -Participants’ expectations about the benefits of MBSR -Helpfulness of the treatments components   Outcome variables -Number of days with pain prior 2 weeks -Pain intensity -Pain duration -State and Trait Anxiety -Mindfulness self-efficacy -Quality of life (physical, emotional, social, and school functional domains) -Catastrophic thoughts -Functional disability	Average number of sessions attended: G1: 4/6 sessions G2: 3/6 sessions In general, participants had positive expectations of the proposed interventions. 75% of the participants in G1 reported expecting that MBSR would be “somewhat” to “completely helpful” at pre-treatment. At 12-week follow-up one participant reported that MBSR was “completely helpful” and another that it was “not at all helpful”. Qualitative individual analyses for outcome variables (data are missing for several participants and for different assessment points) indicate that: -Mindfulness self-efficacy increased for all participants in both groups. -Inconsistent results on the other outcomes measures.
Martin et al. [54]   USA	Meditation   Case series	One group only   ACT   Session details   Number of sessions: 3 Session duration: 2 h over 2 days Session content: -Mindfulness techniques such as mindful breathing -Home practice: ACT exercises to practice between sessions	n = 10 50% girls Mean age = 16.9 years Age range = 12–20 years Dx.: Neurofibromatosis type 1	Assessment points -Baseline -3-month follow-up   Process variables -Treatment adherence -Satisfaction with treatment (adolescent and parents)   Outcomes variables Adolescents: -Pain interference -Pain intensity -Functional disability -Pain acceptance -Pain-related anxiety -Depression -Health-related quality of life (daily, emotional and cognitive functioning, medical/physical status) -Pharmacological and non-pharmacological techniques used by to manage pain -Disease severity (completed by a nurse practitioner)   Parents -Child pain interference -Acceptance of child’s pain -Health-related quality of life (daily, emotional and cognitive functioning, medical/physical status) -Psychological distress (e.g., anxiety, depression, and somatization)	60% of the participants used mindfulness techniques at least once a week at follow-up. Average participant satisfaction with study was 3.9 on a 0–5 scale. Average parent satisfaction with treatment was 4.6 on a 0–5 scale. Significant pre-treatment to follow-up improvements in pain intensity and pain interference were observed. 60% of the participants reported a decrease of medication at follow-up, relative to pre-treatment.   Parents reported a significant pre-treatment to follow-up reduction in pain interference. No significant pre-treatment to follow-up improvements were reported in functional ability, anxiety, depression, quality of life by patient or parent reports, and acceptance of child’s pain.
Ruskin et al. [52]   Canada	Meditation   Pilot uncontrolled clinical study	One group only   MBSR   Session details   Number sessions: 8 Session duration: 2 h Session content (meditation exercises): -Bringing comfort to pain -Kindness to pain -Body scan -Mindful eating -Breathing meditation -Mountain meditation -Loving kindness -Gratitude -Home practice: 5 min daily	n = 16 100% girls Mean age = 5.75 years Age range = 13–17 years Dx.: Neurophatic pain, musculoskeletal pain, abdominal pain, mixed pain, headache	Assessment points -Baseline -Post-treatment   Process variables -Completion rate -Sessions attendance -Recommendation of treatment to others -Importance of learning and practice mindfulness -Confidence in using mindfulness -Helplessness of the intervention (i.e., to cope with pain, negative emotions and to be more kind with themselves) -Favorite activities of the treatment	Completion rate: 81% Average sessions attendance was 6.4 out of 8 sessions. All participants would recommend the intervention. Average importance of learning and practice mindfulness rated as 4.17 out of 5. Average confidence in use mindfulness rated as 4 out of 5. MBSR rated as being useful to cope with pain and negative emotions and for being more kind with themselves (average rating = 3.67 out of 5). Favorite activities of the treatment included: experiential exercises, meeting others with similar life experiences, group discussions, and learning new techniques to cope with pain. Areas of improvement noted: need of more specific and immediate techniques for managing pain flare-ups, need of more time to share pain stories with other participant, and difficulties with getting to the hospital after a school day.
Anbar &Zoughbi [64]   USA	Hypnosis   Case series	One group only   Hypnosis   Session details   Number of sessions: Mean of 2 sessions of hypnosis in clinic with a mean of 3.8 sessions (range 1–16)	n = 30 56.6% female Mean age = 15 years Age range: 10–18 years Dx.: Headache	Assessment points -Baseline -Post-treatment -Follow-up (time not specified)   Outcome variables -Headache frequency -Headache pain intensity	96% of the participants reported pre- to post-treatment decreases in headache frequency and intensity. Pre- to post-treatment improvements were maintained at follow-up for 65% of the sample.
Galini, Shaoul & Mogilner [62]   Israel	Hypnosis   Case series	One group only   Hypnosis   Session details   Number of sessions: 1	n = 20 75% female Age range = 11–18 years Dx.: Chronic recurrent functional abdominal pain	Assessment points -Baseline -Post-treatment   Outcome variables -Pain intensity -Pain frequency	70% of the participants reported pre- to post-treatment improvements in pain intensity and pain frequency.
Kohen & Zajac [63]   USA	Hypnosis   Case series	One group only   Hypnosis   Session details   Number of sessions: 3 to 4	n = 144 66% female Mean age = 11.0 years Age range = 5–15 years Dx.: Headache	Assessment points -Baseline -Post-treatment   Outcome variables -Headache frequency -Headache pain intensity -Headache duration	88% of the participants reported a decrease in headache frequency (from 4.5 to 1.4/week), 87% a decrease in headache pain intensity (10.3 to 4.7 in a 12-point scale), and 26% experienced a resolution in their headache. Headache duration decreased from 23.6 to 3.0 h, on average.
Olness et al. [70]   USA	Hypnosis   Randomized controlled trial	Groups   G1: Placebo-placebo-hypnosis G2: Propranolol-placebo-hypnosis G3: Placebo-propranolol-hypnosis   Session details   Number of sessions: 3 during 12 weeks, 10-week placebo or drug treatment period.	G1: n = 9 44.4% female Mean age = 8.4 years Age range = 6–12 years Dx.: Migraine   G2: n = 11 18.2% female Mean age = 9.6 years Age range = 6–12 years Dx.: Migraine   G3: n = 8 62.5% female/male Mean age = 9.6 years Age range = 6–12 years Dx.: Migraine	Assessment points -Baseline -Post-treatment   Outcome variables -Headache frequency -Headache pain intensity	Participants in the hypnosis group reported a significantly greater pre- to post-treatment decrease in headache frequency relative to control group, but no significant differences were found regarding pain intensity.
Van Tilburg et al. [66]   USA	Hypnosis   Randomized controlled trial	Groups   G1: Standard medical care + listening to recorded hypnotic sessions G2: Standard medical care   Session details (G1)   Number of sessions: 3 biweekly sessions, including 1 booster session + 3 daily sessions. Treatment period: 2 months Session content: Listen to tape with self-exercises ≥5 days/week.	G1: n = 19   G2: n = 15 71% female Age range = 6–16 years Dx: Functional Abdominal Pain	Assessment points -Baseline -Post-treatment   Outcome variables -Pain intensity -Composite score of quality of life (physical, emotional, social, and school functional domains) -School absenteeism -Medication use	Participants in the hypnosis group reported significantly greater pre- to post-treatment improvements in pain intensity and perceived “health related quality of life” than participants in the control group. No significant differences between the hypnosis and control groups were observed in school absenteeism or medication use.
Vlieger et al. [67] Vlieger et al. [68] * Netherlands	Hypnosis   Randomized controlled trial	Groups   G1: Hypnosis G2: Standard medical care + supportive therapy   Session details   Number of sessions: 6 Session duration: 50’over a 3-month period for the G1. Six 30’ session over a 3-month period for the G2.	G1: n = 27 67% female   G2: n = 22 86% female Mean age = 13.2 years Age range = 8–18 years Dx.: Irritable bowel syndrome, functional abdominal pain	Assessment points -Pre-treatment -Post-treatment -1-year follow-up -5-year follow-up   Outcome variables -Pain intensity -Pain frequency (days per month) -General improvement -School absenteeism	Participants in the hypnosis group reported significantly greater pre- to post-treatment improvements in pain intensity and frequency. Participants in the hypnosis group reported significantly greater general pain improvement at 1-year and 5-year follow up. No significant differences between the hypnosis and control groups were observed in school absenteeism at a 5-year follow-up.
Weydert et al. [69]   USA	Hypnosis   Randomized controlled trial	Groups G1: Standard medical care + 4 hypnosis sessions G2: Standard medical care + breathing techniques   Session details Number of sessions: 4 weekly sessions Session content: G1: Progressive relaxation + guided imagery. Listen to tape with self-exercises twice a day. G2: Learning three breathing techniques.	G1: n = 14 77% female Mean age = 11.0 years Dx.: Abdominal pain   G2: n = 8 50% female Mean age = 11.1 years Dx.: Abdominal pain	Assessment points -Pre-treatment -Post-treatment -1-month follow up   Outcome variables -Pain frequency -School absenteeism	Participants in the hypnosis group reported significantly greater pre- to post-treatment improvements in pain frequency that were maintained at 1-month follow up. Participants in the hypnosis group reported significantly greater pre- to post-treatment improvements in school absenteeism that were maintained at 1-month follow up.
Zeltzer et al. [65]   USA	Hypnosis   Case series	One group only Hypnosis   Session details Number of sessions: 6 weekly sessions Session content: acupuncture combined with 20′ of hypnotic sessions.	n = 31 61% female Mean age = 13 years Age range = 6–18 years Dx.: Headache, abdominal pain associated with irritable bowel syndrome, fibromyalgia, complex regional pain syndrome, juvenile rheumatoid arthritis, myofascial back and chest pain	Assessment points -Pre-treatment -Post-treatment   Outcome variables -Average pain intensity -Current pain intensity -Pain interference in functioning -Anxiety -Depression	Children: Participants reported significantly greater pre- to post-treatment improvements in current and average pain intensity; 42.5% of children reported a decrease in current pain. Participants reported significantly greater pre- to post-treatment improvements in pain interference in functioning. Participants reported significantly greater pre- to post-treatment improvements in anxiety (50% of children reported decrease). No significant changes were reported in depression.   Parents: Parents reported significantly greater pre- to post-treatment improvements in current and average pain intensity as well as pain interference in functioning.

* This publication reports on the five-year follow-up of the sample. Data from there participants of the control group are missing; NF: Neurofeedback; SCP: Slow Cortical Potentials; pirHEG: passive infrared hemoencephalography; CNV: Contingent Negative Variation; ACT: Acceptance and Commitment Therapy; MBSR: Mindfulness-based stress reduction; T: temporal area; C: central area; F: frontal area; FP: prefrontal area; P: parietal area; G: group; n: number of participants; Dx.: Diagnosis.