mmHg, 95% CI -5.77 to 3.72, I2 = 0%, p = 0.67, 83 subjects). No effect was noted on diastolic blood pressure during either period (mean difference − 0.07 mmHg, 95% CI -3.09 to 2.94, I2 = 0%, p = 0.96, 83 subjects; mean difference 0.32 mmHg, 95% CI -2.49 to 3.14, I2 = 0%, p = 0.82, 83 subjects). One study noted no effect on arterial blood pressure; 2 studies noted significantly increased systolic blood pressure compared to sham (no pooled analysis). • Outcome – Heart Rate Variability: Low quality evidence (1 study) indicates no effect on heart rate variability. • Outcome – Respiratory Rate: Very low quality evidence (3 studies) indicates a significant increase in respiratory rate compared to sham. No pooled analysis was possible. 2. Atypical mobilization technique vs. sham • Outcome – Alpha amylase activity: Very low quality evidence (1 study) indicates a significant decrease in sympathetic activity in the salivary glands within 10 minutes of treatment. 3. Spinal SNAGs/mobilization with movement vs. sham • Outcome – Skin Conductance: Low quality evidence (4 studies) indicates no effect on skin conductance in the intervention period or post-intervention period. Pooled analysis (2 studies) found no effect in the intervention (mean difference 4.62, CI 95% -2.31 to 11.55, I2 = 0%, p = 0.19, 2 studies, 60 subjects) or post-intervention (mean difference 3.99, CI 95% -3.47 to 11.44, I2 = 0%, p = 0.29, 2 studies, 60 subjects) periods. • Outcome – Skin Temperature: Very low quality evidence (2 studies) indicates no effect on skin temperature. No pooled analysis was possible. 3.1. Peripheral SNAGs/mobilization with movement vs. sham • Outcome – Skin Conductance: Very low quality evidence (1 study) suggests a significant increase in skin conduct-ance compared with sham. • Outcomes – Skin Temperature, Blood Flow: Very low quality evidence (1 study) indicates a significant increase or decrease in skin temperature and blood flow compared to sham. • Outcomes – Heart Rate/Blood Pressure: Very low quality evidence (1 study) suggest an increase in heart rate and blood pressure when compared with sham. 4. HVLA vs. sham • Outcome – Heart Rate Variability: Low quality evidence (4 studies) indicated no effect on heart rate variability. • Outcome – Heart Rate: Very low quality evidence (3 stud-ies) found no effect on heart rate immediately after treat-ment (mean difference − 1.67 bpm, 95% CI -5.33 to 1.98, I2 = 1%, p = 0.37, 3 studies). • Outcome – Blood Pressure: Very low quality evidence (1 study) found no effect on blood pressure immediately, 10 min and 24 hr after treatment. • Outcome: Pupil Diameter: Low quality evidence (1 study) found no acute effect on pupillary control within 5 min of treatment. • Outcome – Plasma concentrations of epinephrine and norepinephrine: Low quality evidence (1 study) found no effect on sympathoadrenal activity. • Outcome – Oxy-hemoglobin concentration: Very low quality evidence (1 study) found no effect on muscle sympathetic nerve activity immediately, 5 min or 30 mins after treatment. Clinical Application & Conclusions The authors conclude that one type of joint manipulative therapy – mobilizations with oscillatory movements – prob-ably produce effects on skin sympathetic nerve activity. This finding, however, has limited clinical relevance. The remain-ing interventions (SNAGs, HVLA) have no acute effect on the studied markers of ANS activity. They suggest that future research consider findings over longer follow-up periods and in patients with chronic pain. It is worth remembering that this study included ONLY studies that employed a sham control comparison. This is the best way to study these effects, but as a result some papers wouldn’t have made ‘the cut’. COMMENT: This is an area where unfortunately, the claims of some practitioners are outpacing our science. This relationship is interesting and the fact is, some clinical outcomes cannot be explained at this point via the existing research. There is much more work to do and I think this will be a burgeoning area in coming years.... The main thing to address, in my opinion, is the length of treatment intervention in these studies. (Many papers in this area employ only one, or just a few, treatments.) Changes in the ANS likely take time to manifest and then logically would take time to reverse. We simply need more research in this area.... 24 Canadian Chiropractor December 2019 CC_Kosim_April19_CSA.indd 1 2019-03-06 10:07 AM www.canadianchiropractor.ca
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