Table 9 Results from three studies included in a systematic review on the effect of spinal manipulation on ‘brain function’, comparing spinal manipulation to a sham intervention
1st Author Year Ref | Type of study subjects | Outcome variable | Was a statistically significant difference between groups observed? | Was there a relationship between brain changes and any clinical outcome? | Time of assessment | Quality classification |
|---|---|---|---|---|---|---|
Sparks 2017 [9] | Symptomatic (mechanical neck pain < of 6 weeks of duration) | Blood oxygenation-level dependent signal (in response to noxious stimuli) | Yes (p < .05) Statistically significant increase of activation in the insular and sensorimotor cortices post-SM compared to control; and in the anterior and posterior cingulate, supplementary motor area, and precentral gyrus post-control compared to SM | Pain intensity assessed but no relationship tested | Immediately after | Acceptable |
Lelic 2016 [14] | “Subclinical neck/spinal pain” | N30 somatosensory evoked potential peak amplitudes | Yes (significant post-intervention difference between-groups reported but without inclusion of the corresponding p-value and mention of the statistical threshold for significance) Statistically significant decrease post-SM (p = .02) but no statistically significant changes post-control (p = .4) | No clinical outcome included | Not reported | Medium |
Baarbé 2018 [15] | Cerebellar inhibition | Yes (p < .001) Statistically significant reduce post-SM compared to control | No clinical outcome included | Unclear (according to Fig. 1 immediately after the motor acquisition task, i.e. about 20 min after intervention) | Medium |