Alain S. Comtois

HEART RATE VARIABILITY MODULATION AFTER MANIPULATION IN PAIN-FREE PATIENTS VS PATIENTS IN PAIN

BACKGROUND The purpose of this study was to examine heart rate variability (HRV) in the presence or the absence of pain in the lower back, while receiving one chiropractic treatment at L5 from either a manually assisted mechanical force (Activator) or a traditional diversified technique spinal manipulation. METHODS A total of 51 participants were randomly assigned to a control (n = 11), 2 treatment, or 2 sham groups (n = 10 per group). Participants underwent an 8-minute acclimatizing period. The HRV tachygram (RR interval) data were recorded directly into a Suunto watch (model T6; FitzWright Company Ltd, Langley, British Columbia, Canada). We analyzed the 5-minute pretreatment and posttreatment intervals. The spectral analysis of the tachygram was performed with Kubios software. RESULTS All groups decreased in value except the control group that reacted in the opposite direction, when comparing the pretests and posttests for the high-frequency component. The very low frequency increased in all groups except the control group. The low frequency decreased in all groups except the sham pain-free group. The low frequency-high frequency ratio decreased in the treatment pain group by 0.46 and in the sham pain-free group by 0.26. The low frequency-high frequency ratio increase was 0.13 for the sham pain group, 0.04 for the control group, and 0.34 for the treatment pain-free group. The mean RR increased by 11.89 milliseconds in the sham pain-free group, 18.65 milliseconds in the treatment pain group, and 13.14 milliseconds in the control group. The mean RR decreased in the treatment pain-free group by 1.75 milliseconds and by 0.01 milliseconds in the sham pain group. CONCLUSION Adjusting the lumbar vertebrae affected the lumbar parasympathetic nervous system output for this group of participants. Adaptation in the parasympathetic output, reflected by changes in high frequency, low frequency, and very low frequency, may be independent of type of adjustment. Therefore, the group differences found in the modulation of the HRV would seem to be related to the presence or absence of pain. The autonomic nervous system response may be specific and sensitive to its effectors organ.

Effects of a manually assisted mechanical force on cutaneous temperature.

OBJECTIVE Digitized infrared segmental thermometry (DIST) is a tool used for measuring cutaneous temperature (CT). This project ascertains the effect of a manually assisted mechanical force producing a chiropractic adjustment in the lumbar spine after the Activator Methods Chiropractic Technique on CT during 2 different time recording periods (TRPs). METHODS Sixty-six healthy subjects (36 women and 30 men) without acute low back conditions or symptoms were recruited. Subjects were randomly divided into 2 groups based on the length of the acclimatization period (8 or 30 minutes; TRP(8) and TRP(30), respectively). In turn, each recording period group was divided into 3 subgroups (n = 11 per subgroup): treatment, sham, and control subgroups. Bilateral DIST was conducted at L-4 (TRP(30)) and L-5 (TRP(8)) using infrared cameras (Subluxation Station Insight 7000; Chiropractic Leadership Alliance, Mahwah, NJ). RESULTS Before treatment (t(-0.5)), the TRP(8) CT was significantly different between the ipsilateral and the contralateral sides for all subgroups. At 10 minutes (t(10)) after intervention, CT increased significantly (P < .05) for the treatment group but not for the sham and control groups. In contrast, there were no significant differences in the TRP(30) CT before treatment between the ipsilateral and the contralateral sides; but at t(10), CT was significantly (P < .05) greater for all 3 subgroups compared with preintervention CT. CONCLUSION Contacting the skin with the instrument with (treatment group TRP(30)) or without (sham group TRP(30)) a thrust with a sustained pressure stronger than the loading principle taught in the Activator Methods Chiropractic Technique protocol or a thrust respecting the standard loading principle (treatment group TRP(8)) of the instrument produced a CT cooling immediately after the adjustment. Furthermore, we observed that when contacting the skin with the instrument with a thrust respecting the standard loading principle (treatment group TRP(8)) of the instrument, it produced a secondary cooling at t(5) followed by a rewarming at t(10). Finally, contacting the skin with the instrument without a thrust and respecting the standard loading principle (sham TRP(8)) of the instrument did not produce a CT change.

PARASPINAL CUTANEOUS TEMPERATURE MODIFICATION AFTER SPINAL MANIPULATION AT L5

OBJECTIVE The purpose of this study was to investigate local paraspinal cutaneous temperature (CT) modifications after spinal manipulative therapy at L5. METHODS Twenty subjects with acute low back symptoms were randomly assigned to either a treatment or a sham group (n = 10 per group). Subjects underwent an 8-minute acclimatizing period. Temperature was measured bilaterally with infrared cameras at the L5 level. In the treatment group, a traditional chiropractic manipulation (lumbar roll technique with a pisiform contact on the ipsilateral mamillary of L5) was delivered, whereas with the sham group, the same technique was used, but no thrust was applied. Cutaneous temperature control measurements were taken 2 minutes before (t(-2)) and immediately after the intervention (t(0)) and at 1, 3, 5, and 10 minutes postintervention (t(1), t(3), t(5), and t(10), respectively). RESULTS At t(0), CT in the treatment group on the treatment side (ipsilateral side) warmed up by 0.2 degrees F, whereas in the sham group, there were no significant temperature modifications on either side. At t(3) relative to t(0), CT in the treatment group on the treatment side warmed by approximately 0.6 degrees F, whereas the contralateral side (nontreatment side) cooled. In the treatment group, significant differences were noted between sides (F = 13.36, P = .002, P = .932) and sides x times (F = 2.97, P = .016, P = .838). CONCLUSION The effects of a lumbar spine manipulation appear noticeable by changes in paraspinal CT measurements at the level of L5. However, the meaning and mechanisms of CT modifications at L5 are still being investigated.

The metabolically healthy but obese postmenopausal woman presents a favourable heart rate variability profile.

Abstract Objective. The purpose of this study was to investigate the heart rate variability (HRV) profile in obese women displaying the metabolically healthy but obese (MHO) phenotype. Design. We studied 47 obese, sedentary postmenopausal women. Subjects were classified as MHO or at risk based on insulin resistance as assessed with the homeostatic model assessment (HOMA) index. Subjects were divided into tertiles according to HOMA values. Subjects in the lower tertile were categorised as MHO while subjects in the upper 2 tertiles represented at risk subjects. Outcome measures were heart rate variability factors (RR intervals, SDNN, LF, HF, pNN50, RMSSD), body temperature, body composition (DEXA) and a lipid profile as well as glucose and insulin. Results. MHO individuals had significantly lower resting heart rate, body temperature, lean body mass as well as fasting insulin and HOMA levels compared to at risk subjects (p < 0.05). In addition, RR intervals, SDNN and LF were significantly higher in MHO individuals (p < 0.05). Moreover, stepwise regression analysis showed that SDNN was an independent predictor of the variation in HOMA in our cohort. Conclusion. Results of the present study indicate that postmenopausal women displaying the MHO phenotype present a favourable HRV profile. Therefore, higher HRV could be associated, at least in part, in the protective profile of MHO individuals.

Inflammatory response following a short-term course of chiropractic treatment in subjects with and without chronic low back pain☆

OBJECTIVE Inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP) have not been evaluated in response to a short course of lumbar spinal manipulation. The purpose of this study is to observe the responses of inflammatory markers (IL-6 and CRP) after a series of 9 chiropractic spinal manipulations. METHODS Twenty-one participants were assigned to a treatment or a control group. Only the treatment group received 9 chiropractic interventions. Pre- and postintervention measures were recorded for blood samples for detection of proinflammatory cytokines IL-6 and CRP. RESULTS Mediators of inflammation (IL-6 and high-sensitivity CRP) were modified by the intervention received in the treatment group, and the effect size demonstrated a tendency toward the control group values. CONCLUSION A total of 9 chiropractic lower back manipulations caused the mediators of inflammation to present a normalization response in individuals suffering from chronic low back pain.

Consistency of cutaneous thermal scanning measures using prone and standing protocols: a pilot study.

OBJECTIVE The goal of this pilot study was to measure paraspinal cutaneous temperature (PCT) in the prone vs standing position. METHODS Ten symptom-free participants were evaluated. Paraspinal cutaneous temperature was recorded. Subjects were acclimated to the treatment room in a prone position for 8 minutes before the PCT was measured. After the prone PCT reading, patients stood. A standing PCT measurement was then taken. RESULTS Paraspinal cutaneous temperature was marginally warmer when subjects were standing vs prone (PCT difference, 0.25 degrees C +/- 0.64 degrees C and 0.62 degrees C +/- 0.67 degrees C for left and right sides, respectively). The right and left side differential was the same in the prone and standing positions. There was a positive Pearson correlation (0.802-0.803; P < .000) between the standing and prone positions for both left and right sides. CONCLUSION There are no differences between the prone or standing PCT measures if symptom-free subjects are given 8 minutes to acclimate before recording PCT measures.

Comparison of Paraspinal Cutaneous Temperature Measurements Between Subjects With and Without Chronic Low Back Pain

OBJECTIVE The purpose of this study was to evaluate the effects of chiropractic manipulative treatment on paraspinal cutaneous temperature (PCT) for subjects with chronic low back pain and compare these PCT findings to subjects without chronic low back pain. METHODS Two groups were created, a symptomatic treatment group (subjects with chronic low back pain, n = 11, 7 males, 4 females) and an asymptomatic, nontreatment group (asymptomatic subjects, n = 10, 6 males, 4 females). Outcomes included the modified Oswestry questionnaire and PCT measurements in the prone position after an 8-minute acclimation period. The treatment group received 9 chiropractic spinal instrument-based manipulative treatments over 2 weeks. Reevaluation was done 2 weeks after the initial evaluation for both groups. RESULTS The preintervention Oswestry results (29.8% ± 11.8%) for the treatment group were higher than the asymptomatic group (10.2% ± 10.6%). The postintervention Oswestry results for the treatment group were 14.20 % ± 11.5%. The resulting Cohens effect size of the spinal manipulation on the Oswestry evaluation is 0.58. The preintervention PCT showed higher temperature for the nontreatment group compared with the treatment group. Comparing the levels associated with low back pain, the nontreatment group PCT was stable, varying from 0.01°C to 0.02°C, whereas the treatment group PCT varied from 0.10°C to 0.18°C. The treatment group postintervention PCT showed an increase in temperature after the 9 visits; however, this did not reach the values of the asymptomatic group. CONCLUSION The PCT readings for subjects with chronic low back pain were lower than the asymptomatic, nontreatment group. The PCT temperature of the treatment group increased after 9 treatments.

Cardiorespiratory demand and rate of perceived exertion during overground walking with a robotic exoskeleton in long-term manual wheelchair users with chronic spinal cord injury: A cross-sectional study

BACKGROUND Many wheelchair users adopt a sedentary lifestyle, which results in progressive physical deconditioning with increased risk of musculoskeletal, cardiovascular and endocrine/metabolic morbidity and mortality. Engaging in a walking program with an overground robotic exoskeleton may be an effective strategy for mitigating these potential negative health consequences and optimizing fitness in this population. However, additional research is warranted to inform the development of adapted physical activity programs incorporating this technology. OBJECTIVES To determine cardiorespiratory demands during sitting, standing and overground walking with a robotic exoskeleton and to verify whether such overground walking results in at least moderate-intensity physical exercise. METHODS We enrolled 13 long-term wheelchair users with complete motor spinal cord injury in a walking program with an overground robotic exoskeleton. Cardiorespiratory measures and rate of perceived exertion (RPE) were recorded by using a portable gas analyzer system during sitting, standing and four 10m walking tasks with the robotic exoskeleton. Each participant also performed an arm crank ergometer test to determine maximal cardiorespiratory ability (i.e., peak heart rate and O2 uptake [HRpeak, VO2peak]). RESULTS Cardiorespiratory measures increased by a range of 9%-35% from sitting to standing and further increased by 22%-52% from standing to walking with the robotic exoskeleton. During walking, median oxygen cost (O2Walking), relative HR (%HRpeak), relative O2 consumption (%VO2peak) and respiratory exchange ratio (RER) reached 0.29mL/kg/m, 82.9%, 41.8% and 0.9, respectively, whereas median RPE reached 3.2/10. O2Walking was moderately influenced by total number of sessions and steps taken with the robotic exoskeleton since the start of the walking program. CONCLUSION Overground walking with the robotic exoskeleton over a short distance allowed wheelchair users to achieve a moderate-intensity level of exercise. Hence, an overground locomotor training program with a robotic exoskeleton may have cardiorespiratory health benefits in the population studied.

Intra and Inter Examiner Reliability Study for the Characteristics of Evaluation of the SA201

Introduction: There is no published account of the reliability of the percussion technology on human participants. Our goal was to measure the reliability of the instrument’s analysis protocol on an inert substance and on human participants with expert and novice evaluators. Method: 15 participants were evaluated by six evaluators, three experienced and three novices. Results: No participants were excluded from the analysis, based on the NDI, ODI and BMI. Even if the global result from the durometer testing were surprising in their range, the effect size score for the pre and post value on the durometer indicate very good reliability. Conclusion: The intra-evaluator reliability is very good when testing on the durometer but less predominant when evaluating the participant. In addition a novice chiropractor can use the instrument with a certain degree of ability that will develop over time if he uses this technology on a regular basis.