Influence of neck proprioception on vibration-induced postural sway

Does Improvement towards a Normal Cervical Sagittal Configuration Aid in the Management of Lumbosacral Radiculopathy: A Randomized Controlled Trial

A randomized controlled study with a six-month follow-up was conducted to investigate the effects of sagittal head posture correction on 3D spinal posture parameters, back and leg pain, disability, and S1 nerve root function in patients with chronic discogenic lumbosacral radiculopathy (CDLR). Participants included 80 (35 female) patients between 40 and 55 years experiencing CDLR with a definite hypolordotic cervical spine and forward head posture (FHP) and were randomly assigned a comparative treatment control group and a study group. Both groups received TENS therapy and hot packs, additionally, the study group received the Denneroll cervical traction orthotic. Interventions were applied at a frequency of 3 x per week for 10 weeks and groups were followed for an additional 6-months. Radiographic measures included cervical lordosis (CL) from C2–C7 and FHP; postural measurements included: lumbar lordosis, thoracic kyphosis, trunk inclination, lateral deviation, trunk imbalance, surface rotation, and pelvic inclination. Leg and back pain scores, Oswestry Disability Index (ODI), and H-reflex latency and amplitude were measured. Statistically significant differences between the groups at 10 weeks were found: for all postural measures, CL (p = 0.001), AHT (p = 0.002), H-reflex amplitude (p = 0.007) and latency (p = 0.001). No significant difference for back pain (p = 0.2), leg pain (p = 0.1) and ODI (p = 0.6) at 10 weeks were identified. Only the study group’s improvements were maintained at the 6-month follow up while the control groups values regressed back to baseline. At the 6-month follow-up, it was identified in the study group that improved cervical lordosis and reduction of FHP were found to have a positive impact on 3D posture parameters, leg and back pain scores, ODI, and H-reflex latency and amplitude.

Does improvement towards a normal cervical sagittal configuration aid in the management of cervical myofascial pain syndrome: a 1- year randomized controlled trial

Background

There is a growing interest concerning the understanding of and rehabilitation of the sagittal configuration of the cervical spine as a clinical outcome. However, the literature on the topic specific to conservative treatment outcomes of patients with chronic myofascial cervical pain syndrome (CMCPS) has not adequately addressed the relationship between cervical sagittal alignment and improved pain, disability and range of motion.

Methods

A randomized controlled study with a 1-year follow-up. Here, 120 (76 males) patients with chronic CMCPS and defined cervical sagittal posture abnormalities were randomly assigned to the control or an intervention group. Both groups received the Integrated neuromuscular inhibition technique (INIT); additionally, the intervention group received the denneroll cervical traction device. Alignment outcomes included two measures of sagittal posture: cervical angle (CV), and shoulder angle (SH). Patient relevant outcome measures included: neck pain intensity (NRS), neck disability (NDI), pressure pain thresholds (PPT), cervical range of motion using the CROM. Measures were assessed at three intervals: baseline, 10 weeks, and 1 year after the 10 week follow up.

Results

After 10 weeks of treatment, between group statistical analysis, showed equal improvements for both the intervention and control groups in NRS (p = 0.36) and NDI (p = 0.09). However, at 10 weeks, there were significant differences between groups favoring the intervention group for PPT (p<0.001) and all measures of CROM (p<0.001). Additionally, at 10 weeks the sagittal alignment variables showed significant differences favoring the intervention group for CV p<0.001 and SH (p<0.001) indicating improved CSA. Importantly, at the 1-year follow-up, between group analysis identified a regression back to baseline values for the control group for the non-significant group differences (NRS and NDI) at the 10-week mark. Thus, all variables were significantly different between groups favoring the intervention group at 1-year follow up: NRS (p<0.001), NDI (p<0.001), PPT p<0.001), CROM (p<0.001), CV (p<0.001), SH (p<0.001).

Conclusion

The addition of the denneroll cervical orthotic to a multimodal program positively affected CMCPS outcomes at long term follow up. We speculate the improved sagittal cervical posture alignment outcomes contributed to our findings.

Trial registration

Pan African Clinical Trial Registry Clinical Trial Registry: PACTR201801002968301, registered 11 January 2018 (retrospectively registered).

Using Balance Tests to Discriminate Between Participants With a Recent Index Lateral Ankle Sprain and Healthy Control Participants: A Cross-Sectional Study

CONTEXT

The first step to identifying factors that increase the risk of recurrent ankle sprains is to identify impairments after a first sprain and compare performance with individuals who have never sustained a sprain. Few researchers have restricted recruitment to a homogeneous group of patients with first sprains, thereby introducing the potential for confounding.

OBJECTIVE

To identify impairments that differ in participants with a recent index lateral ankle sprain versus participants with no history of ankle sprain.

DESIGN

Cross-sectional study.

PATIENTS OR OTHER PARTICIPANTS

We recruited a sample of convenience from May 2010 to April 2013 that included 70 volunteers (age = 27.4 ± 8.3 years, height = 168.7 ± 9.5 cm, mass = 65.0 ± 12.5 kg) serving as controls and 30 volunteers (age = 31.1 ± 13.3 years, height = 168.3 ± 9.1 cm, mass = 67.3 ± 13.7 kg) with index ankle sprains.

MAIN OUTCOME MEASURE(S)

We collected demographic and physical performance variables, including ankle-joint range of motion, balance (time to balance after perturbation, Star Excursion Balance Test, foot lifts during single-legged stance, demi-pointe balance test), proprioception, motor planning, inversion-eversion peak power, and timed stair tests. Discriminant analysis was conducted to determine the relationship between explanatory variables and sprain status. Sequential discriminant analysis was performed to identify the most relevant variables that explained the greatest variance.

RESULTS

The average time since the sprain was 3.5 ± 1.5 months. The model, including all variables, correctly predicted a sprain status of 77% (n = 23) of the sprain group and 80% (n = 56) of the control group and explained 40% of the variance between groups ([Formula: see text] = 42.16, P = .03). Backward stepwise discriminant analysis revealed associations between sprain status and only 2 tests: Star Excursion Balance Test in the anterior direction and foot lifts during single-legged stance ([Formula: see text] = 15.2, P = .001). These 2 tests explained 15% of the between-groups variance and correctly predicted group membership of 63% (n = 19) of the sprain group and 69% (n = 48) of the control group.

CONCLUSIONS

Balance impairments were associated with a recent first ankle sprain, but proprioception, motor control, power, and function were not.

The effect of adding forward head posture corrective exercises in the management of lumbosacral radiculopathy: a randomized controlled study

OBJECTIVE

The purpose of this study was to determine the immediate and long-term effects of a multimodal program, with the addition of forward head posture correction, in patients with chronic discogenic lumbosacral radiculopathy.

METHODS

This randomized clinical study included 154 adult patients (54 females) who experienced chronic discogenic lumbosacral radiculopathy and had forward head posture. One group received a functional restoration program, and the experimental group received forward head posture corrective exercises. Primary outcomes were the Oswestry Disability Index (ODI). Secondary outcomes included the anterior head translation, lumbar lordosis, thoracic kyphosis, trunk inclination, lateral deviation, trunk imbalance, surface rotation, pelvic inclination, leg and back pain scores, and H-reflex latency and amplitude. Patients were assessed at 3 intervals (pretreatment, 10-week posttreatment, and 2-year follow-up).

RESULTS

A general linear model with repeated measures indicated a significant group × time effect in favor of the experimental group on the measures of ODI (F = 89.7; P < .0005), anterior head translation (F = 23.6; P < .0005), H-reflex amplitude (F = 151.4; P < .0005), H-reflex latency (F = 99.2; P < .0005), back pain (F = 140.8; P < .0005), and leg pain (F = 72; P < .0005). After 10 weeks, the results revealed an insignificant difference between the groups for ODI (P = .08), back pain (P = .29), leg pain (P = .019), H-reflex amplitude (P = .09), and H-reflex latency (P = .098). At the 2-year follow-up, there were significant differences between the groups for all variables adopted for this study (P < .05).

CONCLUSIONS

The addition of forward head posture correction to a functional restoration program seemed to positively affect disability, 3-dimensional spinal posture parameters, back and leg pain, and S1 nerve root function of patients with chronic discogenic lumbosacral radiculopathy.

Estimate of body motion during voluntary body sway movements

Balance control can be interpreted as a combination of state feedback control with optimal state estimation. In this framework, state estimation uses an internal model of body and sensor dynamics to process sensory information and determine body orientation. The aim of this study was to assess the ability of the brain to create accurate state estimation when the congruence between sensory information was altered. Participants stood upright on a force platform with a monitor directly in front of them at eye level displaying their center of pressure (CP) position in real-time. When a target appeared on the monitor, participants had to move their CP as fast and as accurately as possible within the target. Voluntary balance pointing movements were made with the head either straight or rotated about the trunk, and mapping directions of the CP were changed on the basis of experimental conditions. Manipulating the sensory information congruency caused less accurate state estimation of the body motion leading to larger signed and absolute angular errors and a greater area of the final CP position were measured. These results suggest that performing head-centered to trunk-centered sensorimotor transformation reduces the accuracy in the state estimation of body motion during a balance pointing task.

A longitudinal study of balance in migraineurs

CONCLUSION

Balance in migraineurs, even in those without vestibular symptoms, deteriorates slightly over 1 year in the most challenging test conditions, when measured with posturography.

OBJECTIVE

To discover by a longitudinal study of a group of migraineurs and their controls, whether the well-known, mild imbalance found on posturography in migraineurs is static or progressive.

METHODS

Posturographic measures of sway under incrementally more challenging conditions (up to eyes closed standing on a foam surface with the head extended) using the modified clinical test of sensory interaction on balance, limits of stability test, and tandem gait tests in a group of 19 migraineurs and 19 age- and gender-matched controls, all of whom who had been tested over 1 year before.

RESULTS

After 1 year migraineurs showed a slight but statistically significant deterioration: in postural sway especially, when measured with eyes closed standing on a foam surface with the head extended backwards; in reaction time; and in maximal excursion on the limits of the stability test; and perhaps in walk speed and step width on the tandem walk test.

Artificial vestibular feedback in conditions of a modified body scheme

Subjects standing in the dark on a rigid immobile support maintained a vertical posture, which was destabilized by vibrostimulation of both Achilles tendons. Feedback was created via the vestibular pathway using transmastoid galvanic stimulation. Changes in the current in the feedback envelope were made using a linear function based on the amplitude and rate of head displacement. Changes in the body scheme were produced using rotation of the head relative to the trunk, rotation of the trunk with the relative head position fixed, and simultaneous rotation of the head and trunk. The result of these manipulations was that the head could be rotated through essentially 90 degrees relative to the feet. In addition, rotation of one foot relative to the other through 90 degrees was used. Artificial feedback damped head oscillations induced by vibration, but only those in the vertical plane passing through the interaural axis of the head. It is suggested that changes in the vectorial characteristics of vestibular responses and the results of applying artificial feedback on the background of modified orientation of the head relative to the feet may be associated with substitution of the ensembles of vestibular hair sets providing the dominant signals in the responses of vestibulospinal neurons.

Reflex control of the spine and posture: a review of the literature from a chiropractic perspective

OBJECTIVE

This review details the anatomy and interactions of the postural and somatosensory reflexes. We attempt to identify the important role the nervous system plays in maintaining reflex control of the spine and posture. We also review, illustrate, and discuss how the human vertebral column develops, functions, and adapts to Earth's gravity in an upright position. We identify functional characteristics of the postural reflexes by reporting previous observations of subjects during periods of microgravity or weightlessness.

BACKGROUND

Historically, chiropractic has centered around the concept that the nervous system controls and regulates all other bodily systems; and that disruption to normal nervous system function can contribute to a wide variety of common ailments. Surprisingly, the chiropractic literature has paid relatively little attention to the importance of neurological regulation of static upright human posture. With so much information available on how posture may affect health and function, we felt it important to review the neuroanatomical structures and pathways responsible for maintaining the spine and posture. Maintenance of static upright posture is regulated by the nervous system through the various postural reflexes. Hence, from a chiropractic standpoint, it is clinically beneficial to understand how the individual postural reflexes work, as it may explain some of the clinical presentations seen in chiropractic practice.

METHOD

We performed a manual search for available relevant textbooks, and a computer search of the MEDLINE, MANTIS, and Index to Chiropractic Literature databases from 1970 to present, using the following key words and phrases: "posture," "ocular," "vestibular," "cervical facet joint," "afferent," "vestibulocollic," "cervicocollic," "postural reflexes," "spaceflight," "microgravity," "weightlessness," "gravity," "posture," and "postural." Studies were selected if they specifically tested any or all of the postural reflexes either in Earth's gravity or in microgravitational environments. Studies testing the function of each postural component, as well as those discussing postural reflex interactions, were also included in this review.

DISCUSSION

It is quite apparent from the indexed literature we searched that posture is largely maintained by reflexive, involuntary control. While reflexive components for postural control are found in skin and joint receptors, somatic graviceptors, and baroreceptors throughout the body, much of the reflexive postural control mechanisms are housed, or occur, within the head and neck region primarily. We suggest that the postural reflexes may function in a hierarchical fashion. This hierarchy may well be based on the gravity-dependent or gravity-independent nature of each postural reflex. Some or all of these postural reflexes may contribute to the development of a postural body scheme, a conceptual internal representation of the external environment under normal gravity. This model may be the framework through which the postural reflexes anticipate and adapt to new gravitational environments.

CONCLUSION

Visual and vestibular input, as well as joint and soft tissue mechanoreceptors, are major players in the regulation of static upright posture. Each of these input sources detects and responds to specific types of postural stimulus and perturbations, and each region has specific pathways by which it communicates with other postural reflexes, as well as higher central nervous system structures. This review of the postural reflex structures and mechanisms adds to the growing body of posture rehabilitation literature relating specifically to chiropractic treatment. Chiropractic interest in these reflexes may enhance the ability of chiropractic physicians to treat and correct global spine and posture disorders. With the knowledge and understanding of these postural reflexes, chiropractors can evaluate spinal configurations not only from a segmental perspective, but can also determine how spinal dysfunction may be the ultimate consequence of maintaining an upright posture in the presence of other postural deficits. These perspectives need to be explored in more detail.