Abstract
Background
Fourth ventricle compression (CV4) is a cranial osteopathic manipulation technique for brain and cranial nerve function. Rib raising is an osteopathic technique that reduces rib restriction and conditions associated with sympathetic hypertonia. This study aimed to evaluate the effects of the CV4 and rib raising osteopathic techniques on autonomic nervous system activity, measured by heart rate variability, in 35 healthy individuals.
Material/Methods
The study involved 35 healthy participants, randomly divided into 2 groups. The experimental group received osteopathic therapy in the form CV4 and rib raising techniques for 30 min. The placebo group had a sham procedure performed using an ultrasound transducer for 20 min. The test of heart rate variability was conducted for 6 min, with participants in a seated position.
Results
A significant decrease in heart rate values was observed in the experimental group (P=0.012), and an increase in the standard deviation of all the rib raising intervals parameter and a decrease in the high frequency% parameter was observed in the placebo group (P=0.035, P=0.048; respectively). There were no differences in other parameters between the groups.
Conclusions
The use of the CV4 technique and rib raising technique leads to a significant decrease in heart rate, which can be interpreted as increased parasympathetic activity; however, the use of these techniques did not affect the other parameters.
Keywords: Manipulation, Osteopathic; Osteopathic Medicine; Heart Rate; Heart Rate Determination; Musculoskeletal Manipulations
Background
A decrease in parasympathetic activity, which is responsible for regenerative functions, digestive functions, and inflammation control, along with an increase in sympathetic activity is associated with the fight-or-flight response. The decrease in parasympathetic activity and increase in sympathetic activity can result in sleep disorders, disruption of brain bioelectrical function, and a reduced ability to generate theta waves. It can also significantly impact the functions of the glymphatic-lymphatic continuum, which is responsible for clearing the central nervous system of medium and large protein molecules and toxins [1,2]. Ultimately, this can increase the risk of developing neurodegenerative diseases, such as Parkinson disease, Alzheimer disease, and multiple sclerosis [1–5]. Notably, the risk of developing Alzheimer disease after the age of 50 is 50% in this group of patients [6].
In addition, Xie et al (2013) found that sympathetic arousal reduces brain interstitial fluid volume and central nervous system detoxification efficiency by more than 60%, which can consequently lead to chronic dysautonomia [7].
Therefore, it seems that early detection of symptoms of dysautonomia (increased sympathetic nervous system excitation and decreased parasympathetic nervous system excitation) and the search for effective evidence-based therapeutic interventions can make a significant contribution to inhibiting or reducing the symptoms of conditions underlying neurodegenerative changes [7].
There is no consensus in the literature as to whether the use of osteopathic techniques in the form of high velocity low amplitude manipulations performed on the cervical and thoracic parts of the spine, techniques aimed at the cranial field, or the use of rib raising techniques produce a significant effect on autonomic nervous system function [8–13]. Some of the studies conducted confirm the effectiveness of osteopathic techniques in normalizing autonomic nervous system function [9–12], while others have shown no such effect [8,13].
Given the divergent opinions on the effectiveness of osteopathic techniques, as well as their increasingly widespread use, the main objective of this study was to verify the effect of osteopathic techniques on autonomic nervous system function, as expressed by heart rate variability (HRV). HRV is a measurement of the variations in the time intervals between consecutive heartbeats. It provides insights into the functioning of the autonomic nervous system, which regulates the balance between the sympathetic and parasympathetic branches, known as the “fight-or-flight” and “rest-and-digest” responses, respectively. HRV is widely used as a noninvasive and objective tool for assessing autonomic nervous system activity and its modulation [10,14,15].
Therefore, this study aimed to evaluate the effects of the fourth ventricle compression technique (CV4) and rib raising osteopathic technique on autonomic nervous system activity measured by HRV in 35 healthy individuals. The participants voluntarily consented to participate in the study and were informed about its methodology and purpose.
HRV parameters refer to various quantitative measures derived from the analysis of HRV. These parameters provide insights into the dynamics and modulation of the heart’s autonomic nervous system activity. Some commonly used HRV parameters are time-domain parameters, frequency-domain parameters, and nonlinear parameters [16].
Time-domain parameters assess the variability time intervals between successive R-peaks on an electrocardiogram (RR intervals) over a specific time period. Examples include the following:
– Standard deviation of normal-to-normal (SDNN) intervals, which measures the overall variability of RR intervals.
– Standard deviation of RR intervals (SDRR), which is used in the analysis of HRV. SDRR measures the overall variability of the RR intervals, which reflects the combined influence of both sympathetic and parasympathetic activities on the heart’s autonomic nervous system.
– Root mean square of successive differences (RMSSD), which reflects short-term HRV and parasympathetic activity.
– Percentage of successive RR intervals differing by more than 50 ms (pNN50), which indicates parasympathetic influence.
Frequency-domain parameters analyze the spectral power distribution of HRV signals. They provide information about the balance between sympathetic and parasympathetic activity. Examples include the following:
– Very low frequency (LF) power, which represents the lowest frequency range (usually <0.04 Hz).
– LF power, which reflects sympathetic and parasympathetic modulation (0.04–0.15 Hz).
– High frequency (HF) power, which indicates parasympathetic activity (0.15–0.4 Hz).
Nonlinear parameters capture the complexity and nonlinear properties of HRV signals. Examples include the following:
– Sample entropy, which quantifies signal irregularity and complexity.
– Poincare plot parameters (SD1 and SD2), which characterize the short-term and long-term HRV dynamics.
These 3 parameters provide valuable information about the autonomic nervous system’s influence on heart rhythm and are widely used in research and clinical settings to assess autonomic function, cardiovascular health, and stress levels.
Material and Methods
Ethics Statement
The local Ethical Committee granted permission for this research (permission number: 2/2016).
After reviewing the documentation related to the research project mentioned above, the Senate Committee on Ethics of Scientific Research concluded that it did not find any elements in the project that were inconsistent with the principles of ethical conduct of research involving humans.
The Committee acknowledged the following:
– The submitted documentation was complete and sufficiently detailed to assess ethical issues arising from the scientific research involving humans.
– The research would not violate the dignity and privacy rights of the participants.
– The necessity to obtain appropriate consent from the research participant for their participation or processing of personal data had been taken into account.
– The research did not pose a threat to the mental health and social functioning of the participants.
– Adequate supervision and documentation control were ensured throughout the study.
– The information provided to the participants about the research was sufficiently detailed and understandable.
– The project respected copyright laws.
Study Population
Inclusion criteria for the study were age 24 to 60 years and participants not currently receiving any form of rehabilitation, physiotherapy, or osteopathy.
Exclusion criteria for the study were as follows: unstable arrhythmia in the patient’s history and symptoms related to chest organs (retrosternal pain, difficulty breathing) [17], pregnancy [17], symptoms suggestive of disorders related to bowel obstruction (bloating with pain, vomiting, diarrhea) [17], smoking [13], surgical treatment in the head [13], neurological diseases [13], menstruation [8], having had physiotherapy or osteopathy treatment within the last month, regardless of the reason [8], back and peripheral joint pain, and trauma and musculoskeletal dysfunction in the last 12 months.
A total of 36 healthy volunteers met the above-mentioned criteria. Next, the study group was randomly divided into an experimental group and a placebo group.
Randomization
Thirty-six participants drew cards from a specially prepared box containing either the letter E, indicating the experimental group, or the letter P, indicating the placebo group. After drawing their card, participants reported their result to the person preparing the cards, who recorded their data and assigned them to a group. All participants signed consent forms and were given detailed documents describing the study, indications, and contraindications. None of the participants knew which group they were assigned to. The person conducting post-therapy measurements was also blinded to participants’ group assignment.
Finally, the experimental group included 17 participants (1 participant resigned from the study), while the placebo group included 18 participants. Characteristics of the participants are presented in Table 1.
Table 1.
Characteristics of the study population.
| Characteristics | Experimental (n=17) | Placebo (n=18) | p | ||
|---|---|---|---|---|---|
| Mean (SD) | Min–Max | Mean (SD) | Min–Max | ||
| Age (years) | 45.6 (10.1) | 24.0–60.0 | 42.3 (11.8) | 24.0–60.0 | 0.371 |
| Weight (kg) | 79.7 (16.6) | 48.9–102.0 | 84.1 (10.6) | 65.0–105.0 | 0.300 |
| Height (cm) | 171.1 (9.8) | 158.0–191.5 | 174.7 (10.0) | 158.0–197.0 | 0.355 |
| Body mass index (kg/m2) | 27.0 (4.5) | 17.9–34.6 | 27.5 (2.2) | 23.0–31.2 | 0.685 |
Intervention in the Experimental Group
Intervention applied in the experimental group was performed with the use of 2 techniques: (1) CV4 and (2) rib raising, which are oriented toward normalizing autonomic nervous system by lowering the heart’s contraction rate [8,18].
The CV4 procedure is a well-known technique in the field of osteopathy. In the CV4 technique, the patient lies down, and the therapist holds the squamous part of the occipital bone, specifically its lateral angles, while manipulating the cranium into extension. The therapist maintains the extension of the cranium and waits for a motionless state. Once the cranial pulse becomes apparent, the therapist can conclude the procedure [15] (Figures 1, 2). The entire procedure lasted 30 min, and its methodology was selected based on recommendations from the literature [13]. According to the assumptions, the technique aims to stimulate the parasympathetic nervous system by affecting the vagus nerve and improving the brain’s glymphatic system [9].
Figure 1.
Position of the therapist and the patient during fourth ventricle compression technique.
Figure 2.
Alignment of the therapist’s hand during fourth ventricle compression technique.
For the rib raising technique, the participant was in a supine position on a therapy table. The therapist was in a sitting position on the participant’s left side. The therapist’s phalanges were placed near the angles of the ribs and applied pressure in the abdominal and lateral directions so that there was movement in the costovertebral joint. The pressure and the pause in its execution lasted for 5 s each. The technique was started from ribs I–IV (Figures 3, 4). After 10 cycles (pressure-break), the technique was performed on ribs V–VIII (10 cycles), followed by ribs IX–XII (10 cycles). After the entire procedure was performed 3 times on the left side, it was repeated on the right side for 3 times. The entire procedure for both sides took about 30 min. Its methodology was selected based on recommendations from the literature [11]. According to the guidelines, the technique aims to mobilize the costovertebral joint, through which it should affect the local metabolism of autonomic sympathetic ganglia and inhibit the activity of the sympathetic nervous system [11]. Osteopathic diagnosis of the ribs can assist in distinguishing between rib somatic dysfunction and referred pain originating from thoracic viscera. This differentiation is crucial for accurate diagnosis and effective management options. Previous studies have shown that osteopathic manipulative treatment is effective in alleviating pain and improving thoracic motion in patients with conditions such as costochondritis, costovertebral joint dysfunction, and post-sternotomy rib dysfunction. These findings highlight the potential benefits of osteopathic manipulative treatment in providing relief and improving function in patients with rib-related issues [19]. The rib raising technique aims to reduce rib restriction and address conditions associated with sympathetic hypertonia. This technique has been used to improve thoracic motion and relieve pain in various rib-related dysfunctions [19].
Figure 3.
Position of the therapist and the patient during the rib raising technique.
Figure 4.
Position of the therapist’s hands during rib raising technique.
Placebo Intervention in the Control Group
For the sham therapeutic technique, the participant was in a prone position on the therapy table. The examiner moved the ultrasound transducer in the thoracic region of the spine in an area 10 cm from the level of the spinous processes on both sides and in the suboccipital region. Prior to the procedure, the participant was informed that, using the ultrasound probe, the therapist would look for areas with increased tissue tension, which would be “confirmed” by the red color on the ultrasound monitor. Tissue relaxation was mimicked by a color change to green. The total intervention time was 20 min (Figure 5).
Figure 5.
Sham therapeutic technique, using ultrasound on the patient’s back.
The techniques were executed by an osteopath who has both osteopathic and physiotherapy qualifications and 14 years of clinical experience.
HRV Study Protocol
The HRV test was used to evaluate autonomic nervous system function [12,13,20]. For the study, an EEG/HRV/RSA Infiniti 8 measuring device, ProComp Infiniti encoder, and Biograph Infiniti and Physiology Suit software from Biomed Neurotechnologie were used (www.biomed.org.pl 01.06.2022) [21].
The test took place with the participant in a sitting position. Before the test, the participant was asked to sit in a chair for 5 min to calm down and get accustomed to the sitting position. After the procedure, the participant was also asked to sit for 5 min in a chair before the HRV test was conducted. The participants were instructed to breathe calmly in a way that was natural to them during the 6-min test. The participants were also asked to avoid moving the finger to which the measuring apparatus was connected. After the procedure, a certified physiotherapist for HRV testing processed the test result from artifacts.
Statistical Analysis
The statistical analysis was conducted using Statistica 13.3 (StatSoft, Poland). The Shapiro-Wilk test was used for the assessment of the distribution of variables. Data are presented as mean and standard deviation for somatic parameters (age, weight, height, body mass index), and median, minimum, maximum, and first and third quartiles for parameters of heart rate (HR) variables (SBP, DBP, HR, HRV, SDRR, LF%, HF%, HRV LF/HF). The Wilcoxon signed-rank test was conducted to examine the differences in parameters of HR variables before and after the intervention. The Mann-Whitney U test was used to compare the groups before and after the intervention. The statistical significance was set at P<0.05.
The power of the test was calculated using G*Power 3.1.9.7 (Dusseldorf, Germany). The post-hoc power analysis for the t statistic of 2 dependent groups for HR values in the experimental group was 0.81 (n=35, M1=77.5, M2=73.2, SD1=10.5, SD2=8.8, ES=0.44).
Results
Pre-Intervention Group Comparison
Table 2 shows the SBP, DBP, and HRV parameters before the study in the experimental and placebo groups (Table 2). Before the study, no statistically significant differences were observed in the measured parameters between the groups.
Table 2.
The systolic and diastolic blood pressure and heart rate variability parameters in experimental and placebo groups before the intervention.
| Parameter | Group | Median | Min | 1st Qu | 3rd Qu | Max | p |
|---|---|---|---|---|---|---|---|
| SBP | Experimental | 120.0 | 100.0 | 110.0 | 125.0 | 150.0 | 0.321 |
| Placebo | 120.0 | 110.0 | 120.0 | 135.0 | 140.0 | ||
| DBP | Experimental | 80.0 | 60.0 | 75.0 | 80.0 | 100.0 | 0.459 |
| Placebo | 80.0 | 70.0 | 80.0 | 90.0 | 90.0 | ||
| HR | Experimental | 78.0 | 65.0 | 70.0 | 80.0 | 100.0 | 0.276 |
| Placebo | 72.5 | 60.0 | 65.0 | 80.0 | 100.0 | ||
| HRV (Hz) | Experimental | 0.07 | 0.02 | 0.05 | 0.14 | 0.23 | 0.869 |
| Placebo | 0.07 | 0.02 | 0.06 | 0.12 | 0.19 | ||
| SDRR | Experimental | 44.85 | 17.61 | 25.37 | 53.73 | 104.24 | 0.960 |
| Placebo | 32.56 | 19.57 | 28.85 | 48.85 | 106.57 | ||
| LF% | Experimental | 33.82 | 13.84 | 26.50 | 53.10 | 74.40 | 0.882 |
| Placebo | 36.25 | 21.92 | 29.45 | 46.21 | 64.10 | ||
| HF% | Experimental | 29.43 | 13.00 | 23.86 | 41.33 | 76.80 | 0.934 |
| Placebo | 29.76 | 7.48 | 23.52 | 46.91 | 72.84 | ||
| HRV LF/HF | Experimental | 1.16 | 0.20 | 0.72 | 2.71 | 5.14 | 0.830 |
| Placebo | 1.43 | 0.51 | 0.68 | 1.92 | 4.91 |
SBP – systolic blood pressure; DBP – diastolic blood pressure; HR – heart rate; HRV – heart rate variability; SDRR – standard deviation of all the RR intervals; LF% – low frequency; HF% – high frequency; HRV LF/HF – heart rate variability low frequency/high frequency.
Pre- and Post-Intervention Comparison of Results
A significant decrease in HR values was observed in the experimental group (P=0.012), and significant changes in the parameter SDRR and HF% power mean were observed in the placebo group (P=0.035, P=0.048; respectively) (Table 3). However, it should be noted that the standard deviations of all the RR interval parameters is more suitable for 24-h measurements and may not be reliable for short-term measurements. The HF% parameter, which reflects vagus nerve tone, increased in the experimental group (from 29.43 to 36.40), although the change was not statistically significant.
Table 3.
Comparison of systolic and diastolic blood pressure and HRV parameters before and after intervention in the experimental and placebo groups.
| Parameter | Median | Min | 1st Qu | 3rd Qu | Max | p | |
|---|---|---|---|---|---|---|---|
| Experimental group | |||||||
| SBP | Before | 120.0 | 100.0 | 110.0 | 125.0 | 150.0 | 0.136 |
| After | 120.0 | 90.0 | 110.0 | 120.0 | 140.0 | ||
| DBP | Before | 80.0 | 60.0 | 75.0 | 80.0 | 100.0 | 0.103 |
| After | 80.0 | 60.0 | 75.0 | 80.0 | 90.0 | ||
| HR | Before | 78.0 | 65.0 | 70.0 | 80.0 | 100.0 | 0.012 |
| After | 70.0 | 60.0 | 70.0 | 75.0 | 95.0 | ||
| HRV (Hz) | Before | 0.07 | 0.02 | 0.05 | 0.14 | 0.23 | 0.185 |
| After | 0.11 | 0.03 | 0.10 | 0.14 | 0.29 | ||
| SDRR | Before | 44.85 | 17.61 | 25.37 | 53.73 | 104.24 | 0.084 |
| After | 51.56 | 23.55 | 33.99 | 64.09 | 113.77 | ||
| LF% | Before | 33.82 | 13.84 | 26.50 | 53.10 | 74.40 | 0.435 |
| After | 38.33 | 14.54 | 26.59 | 57.75 | 92.52 | ||
| HF% | Before | 29.43 | 13.00 | 23.86 | 41.33 | 76.80 | 0.906 |
| After | 36.40 | 4.94 | 15.35 | 51.17 | 77.75 | ||
| HRV LF/HF | Before | 1.16 | 0.20 | 0.72 | 2.71 | 5.14 | 0.723 |
| After | 1.03 | 0.18 | 0.56 | 1.90 | 16.19 | ||
| Placebo group | |||||||
| SBP | Before | 120.0 | 110.0 | 120.0 | 135.0 | 140.0 | 0.180 |
| After | 120.0 | 110.0 | 120.0 | 130.0 | 140.0 | ||
| DBP | Before | 80.0 | 70.0 | 80.0 | 90.0 | 90.0 | 0.180 |
| After | 80.0 | 70.0 | 80.0 | 90.0 | 95.0 | ||
| HR | Before | 72.5 | 60.0 | 65.0 | 80.0 | 100.0 | 0.686 |
| After | 75.0 | 60.0 | 65.0 | 75.0 | 100.0 | ||
| HRV (Hz) | Before | 0.07 | 0.02 | 0.06 | 0.12 | 0.19 | 0.856 |
| After | 0.10 | 0.02 | 0.06 | 0.12 | 0.20 | ||
| SDRR | Before | 32.56 | 19.57 | 28.85 | 48.85 | 106.57 | 0.035 |
| After | 41.03 | 12.67 | 30.86 | 53.26 | 145.54 | ||
| LF% | Before | 36.25 | 21.92 | 29.45 | 46.21 | 64.10 | 0.306 |
| After | 39.29 | 23.73 | 28.91 | 57.91 | 39.29 | ||
| HF% | Before | 29.76 | 7.48 | 23.52 | 46.91 | 72.84 | 0.048 |
| After | 23.14 | 5.60 | 15.84 | 39.22 | 78.32 | ||
| HRV LF/HF | Before | 1.43 | 0.51 | 0.68 | 1.92 | 4.91 | 0.778 |
| After | 1.97 | 0.11 | 0.96 | 3.58 | 15.33 | ||
SBP – systolic blood pressure; DBP – diastolic blood pressure; HR – heart rate; HRV – heart rate variability, SDRR – standard deviation of all the RR intervals; LF% – low frequency; HF% – high frequency; HRV LF/HF – heart rate variability low frequency/high frequency. Significant difference marked in bold.
Post-Intervention Results Compared Between Groups
After the intervention, there were no differences between the experimental and placebo groups (Table 4). Although the largest change was observed in the HF% parameter between the experimental group (36.40%) and placebo group (23.14%), the difference was not statistically significant (P=0.111).
Table 4.
Comparison of systolic and diastolic blood pressure and HRV parameters in experimental and placebo groups after intervention.
| Parameter | Group | Median | Min | 1st Qu | 3rd Qu | Max | p |
|---|---|---|---|---|---|---|---|
| SBP | Experimental | 120.0 | 90.0 | 110.0 | 120.0 | 140.0 | 0.134 |
| Placebo | 120.0 | 110.0 | 120.0 | 130.0 | 140.0 | ||
| DBP | Experimental | 80.0 | 60.0 | 75.0 | 80.0 | 90.0 | 0.133 |
| Placebo | 80.0 | 70.0 | 80.0 | 90.0 | 95.0 | ||
| HR | Experimental | 70.0 | 60.0 | 70.0 | 75.0 | 95.0 | 0.817 |
| Placebo | 75.0 | 60.0 | 65.0 | 75.0 | 100.0 | ||
| HRV (Hz) | Experimental | 0.11 | 0.03 | 0.10 | 0.14 | 0.29 | 0.181 |
| Placebo | 0.10 | 0.02 | 0.06 | 0.12 | 0.20 | ||
| SDRR | Experimental | 51.56 | 23.55 | 33.99 | 64.09 | 113.77 | 0.283 |
| Placebo | 41.03 | 12.67 | 30.86 | 53.26 | 145.54 | ||
| LF% | Experimental | 38.33 | 14.54 | 26.59 | 57.75 | 92.52 | 0.987 |
| Placebo | 39.29 | 23.73 | 28.91 | 57.91 | 39.29 | ||
| HF% | Experimental | 36.40 | 4.94 | 15.35 | 51.17 | 77.75 | 0.347 |
| Placebo | 23.14 | 5.60 | 15.84 | 39.22 | 78.32 | ||
| HRV LF/HF | Experimental | 1.03 | 0.18 | 0.56 | 1.90 | 16.19 | 0.262 |
| Placebo | 1.97 | 0.11 | 0.96 | 3.58 | 15.33 |
SBP – systolic blood pressure; DBP – diastolic blood pressure; HR – heart rate; HRV – heart rate variability; SDRR – standard deviation of all the RR intervals; LF% – low frequency; HF% – high frequency; HRV LF/HF – heart rate variability low frequency/high frequency.
Discussion
The purpose of this study was to assess autonomic nervous system activity through the measurement of HRV using the CV4 and rib raising techniques. Our findings suggest that the CV4 and rib rising techniques had a noticeable effect on only 1 HRV-related parameter, namely the HR, which was decreased after intervention. This could be interpreted as a positive impact on the parasympathetic nervous system. On the other hand, the placebo group showed a significant increase in the parameter SDRR (from 32.56 to 41.03, P=0,035), indicating greater variability in sinus rhythm, while the experimental group showed a non-statistically significant increase in this parameter (from 44.85 to 51.56, P=0.084).
It is worth noting that the parameter SDRR may not be reliable with short measurements and is more suitable for 24-h measurements [22]. Moreover, in the placebo group, a significant decrease in the HF% mean power parameter was observed, from 29.76 to 23.12. This decrease in the parameter indicates a reduction in the effect of the vagus nerve on the sinus node, leading to a decrease in HRV, increase in sympathetic nervous system excitation, and decrease in parasympathetic nervous system excitation. On the other hand, the experimental group showed an increase in the HF% mean power parameter (from 29.43 to 36.40), although the change was not statistically significant. This suggests a potential beneficial effect of the CV4 and rib raising techniques on the parasympathetic nervous system, as indicated by the increase in the HF% mean power parameter.
Currently, there is no consensus on whether osteopathic manual techniques can significantly affect autonomic nervous system function, nor has it been determined what the potential duration of the therapeutic effect might be. It seems that one of the possible limitations of such verification was the use of only a single treatment procedure in most studies to date, which, as the authors point out, may have led to the application of too weak of a stimulus to induce a significant change in the parameters determining autonomic nervous system function [14].
Henderson et al (2010) demonstrated the effect of the rib raising technique on the autonomic nervous system (increasing parasympathetic activity) by its increasing salivary alpha-amylase levels, an important indicator for assessing parasympathetic nervous system activity [11]. Giles et al (2013) demonstrated the effect of performing “soft tissue” and “suboccipital decompression” techniques on greater variability in HRV and thus increased parasympathetic activity [10]. Curi et al (2017) demonstrated the effect of the CV4 technique on reducing blood pressure and increasing HRV [9]. Mauro (2017), on the other hand, showed a significant effect of osteopathic cranial techniques freely chosen by the osteopath and narrowed to the craniosacral area, as compared with simply applying the hand to the same area in participants, after an acute stressor, on increasing HRV and decreasing salivary cortisol levels [12]. Cardaso et al (2015) and Milnes and Moran (2007), however, showed no effect of the CV4 technique on HRV [8,13]. Cardoso et al (2015) conducted a randomized control trial to evaluate the effects of the CV4 technique on various physiological parameters. The findings of the study indicated that the CV4 technique did not have any significant impact on plasmatic catecholamine levels, blood pressure, or HR. Therefore, the authors suggested that additional studies are needed to provide more comprehensive insights into the potential benefits and applications of the CV4 technique in these areas [8].
In a study conducted by Arienti et al (2020), 32 healthy individuals were divided into a CV4 group, rib raising group, and placebo group, and HRV parameters and skin conductance were measured. The rib raising technique group showed a significant decrease in LF/HF ratio (P<0.001) and LF (P<0.001), and an increase in HF (P<0.001). The CV4 technique group showed a significant reduction of the LF/HF ratio (P<0.001), significant decrease in LF (P<0.001), and significant increase in HF. The researchers suggest that both techniques have a beneficial effect on the autonomic nervous system by increasing parasympathetic dominance [23].
Abenavoli et al (2020) conducted a pilot study on 90 participants, who were divided into 3 groups: an experimental group, in which the CV4 technique was performed, a sham group, and a control group. Salivary alpha-amylase levels were measured before, immediately after, and 30 min after the intervention. A significant increase in salivary alpha-amylase level was found immediately after the CV4 technique was performed (P=0.05), with a significant difference from the control group, but no significant difference from the sham group [24].
The systematic review conducted by Amoroso Borges et al (2018) aimed to evaluate the impact of these manual therapy approaches on HRV. Through a comprehensive analysis of relevant studies, the authors found that spinal manipulation and myofascial techniques had positive effects on HRV. These interventions were associated with increased parasympathetic activity and improved autonomic balance, indicating potential benefits for cardiovascular health and stress reduction. The findings of their systematic review support the use of spinal manipulation and myofascial techniques as valuable strategies in promoting HRV and overall autonomic function [25].
HRV is a commonly used parameter in studies investigating the effects of therapeutic techniques on autonomic nervous system function [8–10,12,13,20]. Time parameters, such as the SDRR parameter, and frequency parameters, such as HF%, LF%, and HRV LF/HF, are often analyzed. The SDRR parameter reflects the time between heartbeats, with a larger value indicating greater HRV and thus better autonomic control. The LF parameter is associated with sympathetic nervous system activity and depends on arterial baroreceptor reactivity, with a higher value indicating greater sympathetic activity. The HF parameter reflects parasympathetic system activity and corresponds to respiratory irregularity resulting from increased vagus nerve inhibition of the sinus node during expiration; a higher value indicates greater parasympathetic activity and thus greater HRV. Low HF levels can be linked to anxiety, stress, panic, and worry [22]. A high LF/HF ratio score indicates sympathetic nervous system dominance, while a low score indicates parasympathetic nervous system dominance [16,21,22].
Limitations of the Study
One limitation of the study was the use of only 1 treatment session, which may have had insufficient stimulation needed to change parameters related to the autonomic nervous system. Another limitation was the treatment time, which may have been too short to affect the autonomic nervous system. However, the techniques used were based on recommendations from the literature [9–12], and therefore we concluded it was necessary to verify the therapeutic procedures as they are used in clinical practice and research. It is also worth noting that the level of participants’ physical activity was not considered. Therefore, in further studies, this factor should be included.
Clinical Relevance of the Study
The clinical value of the study was the use of techniques commonly used in clinical practice [9–12]. In addition, these techniques are often used in research studies, and the evaluation of their effects on the autonomic nervous system varies [8–13]. This study has shown that these techniques may have the slight effect of increasing parasympathetic nervous system activity. However, caution should be exercised in such an evaluation, owing to the fact that the observed changes involved only one of the parameters assessed (HR).
It is important to note that the HRV parameter we used in the study has limitations, as there are no established norms for each specific parameter. Additionally, it should be noted that our study was conducted on a small group of healthy individuals, and we observed only 1 indicator of autonomic activity (HR). Therefore, it would be valuable to conduct further research with a larger sample size and more specific analysis of autonomic nervous system indicators.
Conclusions
The application of the CV4 and rib raising techniques results in a noteworthy decrease in HR, indicating an increase in parasympathetic activity. Nonetheless, as most of the evaluated parameters were not affected, it is essential to conduct additional research to confirm the effects of osteopathic techniques on autonomic nervous system function.
There is a possibility that the combination of 2 techniques, instead of performing them separately, had a negative impact on the study results and did not affect the other parameters of HRV.
Footnotes
Conflict of interest: None declared
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Declaration of Figures’ Authenticity
All figures submitted have been created by the authors who confirm that the images are original with no duplication and have not been previously published in whole or in part.
Financial support: None declared
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