Table 2 Description of eight studies included in a systematic review on the effect of spinal manipulation on ‘brain function’, comparing spinal manipulation to an inactive control
1st author Yr Ref | Design | Type of study subjects | Number of study subjects (males/females) | -Age (range) -Mean | -Type of spinal manipulation -Type of control | How was cerebral activity measured? | When was cerebral activity measured? | Clinical outcomes assessed (measurement tool and time of assessment) |
|---|---|---|---|---|---|---|---|---|
Kelly 2000 [16] | Randomized controlled trial | Healthy: volunteer chiropractic students with evidence of upper cervical “subluxation”. | 36 (9 / 9) intervention group / (11 / 7) control group | -20-37 (both groups) -24 (both groups) | -Toggle (X1) -Control: 2 min of resting | Mental rotation reaction-time task | Before After: exact time unknown | None |
Dishman 2002 [17] | Non-randomized controlled trial | Healthy: healthy college students, volunteers | 24 (? /?) (repartition in each group not reported) | -? /? -25 intervention group / 27 control group | -HVLA L5-S1 (X1) -Control: side posture positioning without lower limb flexion, truncal torque, or manual contact | MEP amplitudes | Before After: -immediately (20 to 120 s) -5 min −10 min | None |
Dishman 2008a [18] | Randomized controlled trial | Healthy: healthy chiropractic students, volunteers | 72 (21 / 5) intervention group / (15 / 8) control 1 / (14 /9) control 2 | -? (3 groups, said to be between their 20s and 30s) -? (3 groups) | -HVLA L5-S1 (X1) -Control 1: L5-S1 preloading -Control 2: side posture positioning | MEP amplitudes | Before (10 MEP recorded during 100 s) After: immediately (10 MEP recorded during 100 s) | None |
Fryer 2012 [16] | Crossover controlled trial (order of interventions randomized) | Healthy: healthy university students, volunteers | 14 (10 / 4) | -18-50 -23 | -HVLA L5-S1 (X2 to 4) -Control: bilateral side-posture positioning without truncal torque, or manual contact | MEP latencies and amplitudes Silent periods | Before After: exact time unknown (according to the Discussion approximately 10 min after) | None |
Ogura 2011 [19] | Crossover controlled trial (order of interventions “counterbalanced”) | Symptomatic: volunteers, recruited at the local university, with mechanical cervical pain and shoulder stiffness. | 12 (12 / 0) | -21–40 -28 | -Instrumentally assisted manipulation (location and nb of spinal levels adjusted unknown) -Control: 20 min of resting | Regional cerebral metabolic rate (rate of glucose consumption) | No before measurementAfter: between 35 to 55 min post- intervention or resting | -Stress Response Scale (immediately after interventions) -European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (immediately after interventions) -Pain intensity (visual analogue scale) (before and immediately after spinal manipulation, not before- after-20 min of resting) |
Inami 2017 [8] | Crossover controlled trial (order of interventions randomized) | Symptomatic: volunteers (unclear origin – probably the same as Ogura et al. 2011) with mechanical cervical pain and shoulder stiffness. | 21 (21 / 0) | -? -26 | -Instrumentally assisted manipulation (where needed, anywhere at the spine, sacroiliac joints and/or scapulae, mean of 8 per subject) -Control: 20 min of resting | Regional cerebral metabolic rate (rate of glucose consumption) | No before measurement After: between 35 min to 1.05 h. post-intervention or resting | Pain intensity (visual analogue scale) (before and immediately after spinal manipulation, and before and after 20 min of resting, only for 9/21 subjects) |
Haavik-Taylor 2007aa [20] | Crossover controlled trial (order of interventions randomized) | “Subclinical neck/spinal pain”: volunteers (unknown origin) with a history of recurring neck pain or stiffness and with evidence of cervical spinal dysfunction, pain free at the time of the study. | 13 (5 / 8) | -22-45 -31 | -HVLA cervical (X2 to 3 per subject) -Control 1: passive head movement without loading and thrust -Control 2: nothing | MEP amplitudes CSP durations | Before After: -within 0–10 min -within 10–20 min -within 20–30 min | None |
Haavik-Taylor 2010b [21] | Crossover controlled trial (order of interventions randomized) | “Subclinical neck/spinal pain”: student and university staff members, volunteers, with reoccurring neck problems and evidence of cervical spine dysfunction, pain free at the time of the study. | 11 (4 / 7) | -22-40 -29 | -HVLA cervical (nb unknown, may be at several levels) + 20 min of typing task -Control: 20 min of typing task only | SEP MU/M + U peak ratios: -P14-N18 complex -Parietal N20 (N20-P25 complex) -Frontal N30 (P22-N30 complex) | Before After: exact time unclear (said to be immediately after HVLA+ 20 min of typing task or after 20 min typing task only, but also said to be within 25 min post interventions, i.e. possibly within 45 min after spinal manipulation) | None |