Gait-dependent integration of neck muscle afferent input

The Role of the Cervical Spine in Dizziness

The neck can be implicated in dizziness via several, separate, discreet mechanisms. Proprioceptive cervicogenic dizziness (CGD) is the most common and reflects the cervical spine's important role, along with visual and vestibular input, for sensorimotor control. Impaired cervical proprioception can lead to symptoms such as dizziness, unsteadiness, visual disturbances, and altered sensorimotor control, and treatment directed toward cervical musculoskeletal and sensorimotor control is efficacious to improve this in individuals with cervical musculoskeletal disorders. Despite this, CGD is difficult to diagnose. Many people present with both neck pain and dizziness, and often the onset of both follows head and neck trauma, but neither necessarily implicate the neck as the cause of dizziness. Further, people often present with mixed forms of dizziness. Thus, rather than diagnosing CGD, it might be more important to consider the potential for the neck to have no (nil, co-morbid cervical condition) or some (minor, major, or compensatory) role in dizziness. Determining the precise role of the cervical spine role in dizziness requires a skilled interview and examination for cervical musculoskeletal and related sensorimotor impairments and relevant testing of other potential causes. A combination and cluster of test outcomes in addition to comparing responses to specific tests when the cervical afferents are stimulated and not stimulated will be important. Considering the role of the neck in dizziness will allow a balanced approach in assessment and management to allow timely, effective intervention to be provided to the large number of individuals presenting with neck pain and dizziness (Supplemental Digital Content, available at: http://links.lww.com/JNPT/A484).

Balance alterations are associated with neck pain and neck muscle endurance in migraine

BACKGROUND

Migraine patients may present with both cervical and balance dysfunctions. The neck plays an important role in balance by providing substantial proprioceptive input, which is integrated in the central nervous system and influences the balance control systems. Whether balance and neck dysfunctions are associated in patients with migraine is still to be explored.

OBJECTIVES

This study aimed to assess the association between the sensory organization test of balance with neck pain features, cervical strength, endurance, and range of motion in patients with migraine.

METHODS

Sixty-five patients with migraine underwent the sensory organization test assessed with the Equitest-Neurocom® device. Maximum voluntary isometric contraction, cervical flexion and extension range of motion, and cervical flexor and extensor endurance were assessed. In addition, the features of migraine and neck pain were collected. Patients were dichotomized according to cut-off scores of balance performance and the association between outcomes were explored.

RESULTS

Patients with reduced balance performance presented a higher frequency of migraine (p = 0.035), a higher frequency of aura (p = 0.002), greater neck pain intensity (p = 0.013), and decreased endurance of cervical flexors (p = 0.010) and extensors (p < 0.0001). The total balance score was correlated with age (r = -0.33; p = 0.007), migraine frequency (r = -0.29; p = 0.021), neck pain intensity (r = -0.26; p = 0.038), and endurance of the cervical flexors (r = 0.39; p = 0.001) and extensors (r = 0.36; p = 0.001). Migraine frequency, neck pain intensity, and endurance of the cervical flexors can predict 21% of the sensory organization test variability.

CONCLUSION

Neck pain features and endurance of the cervical muscles are related to reduced balance performance in patients with migraine. These results shed light to a better understanding of balance alterations in migraine patients.

The effect of mechanical vibration-based stimulation on dynamic balance control and gait characteristics in healthy young and older adults: A systematic review of cross-sectional study

BACKGROUND

A good dynamic balance control and stable gait played an important role in the daily ambulation, especially for older adults with sensorimotor degeneration. This study aimed to systematically review the effects and potential mechanisms of mechanical vibration-based stimulation (MVBS) on dynamic balance control and gait characteristics in healthy young and older adults.

METHOD

Five bioscience and engineering databases, including MEDLINE via PubMed, CINAHL via EBSCO, Cochrane Library, Scopus, and Embase, were searched until September 4th, 2022. Studies published between 2000 and 2022 in English and Chinese involving mechanical vibration related to gait and dynamic balance were included. The procedure was followed via the preferred reporting items for systematic reviews and meta-analysis method. The methodological quality of included studies was assessed using the NIH study quality assessment tool for observational cohort and cross-sectional studies.

RESULTS

A total of 41 cross-sectional studies met the inclusion criteria and were included in this study. Eight studies were good-quality while 26 were moderate-quality and 7 were poor-quality. There were six categories of MVBS at various frequencies and amplitudes utilized in included studies, including plantar vibration, focal muscle vibration, Achilles tendon vibration, vestibular vibration, cervical vibration, and vibration on nail of hallux.

SIGNIFICANCE

Different types of MVBS targeting different sensory systems affected the dynamic balance control and gait characteristics differently. MVBS could be used to provide improvement or perturbation to specific sensory systems, to induce different sensory reweight strategies during gait.

Effectiveness of therapeutic massage for improving motor symptoms in Parkinson's disease: A systematic review and meta-analysis

Background

Parkinson's disease (PD) causes movement disorders [called motor symptoms (MS)], and motor dysfunction poses a great barrier to the quality of life. Although pharmacological therapy like levodopa can relieve the symptoms, it can also cause complications, such as psychosis, nausea, and dyskinesia. A therapy with more minor side effects is needed for PD. Therapeutic massages are the most commonly used forms of complementary and alternative medicine (CAM), but no systematic review and meta-analysis have focused on the efficacy of massage on PD.

Objective

To evaluate the quality of evidence and efficacy of therapeutic massage for improving MS in PD.

Methods

We independently searched four electronic databases, including Chinese National Knowledge Infrastructure (CNKI), MEDLINE/PubMed, Embase, and Cochrane Library, for randomized controlled trials (RCTs) about therapeutic massage and other available manual therapies improving MS in PD from January 1, 2012, to December 31, 2021 (recent 10 years). The main outcome measures were total effectiveness and the Unified Parkinson's Disease Rating Scale (UPDRS), including UPDRS total, II, and III. For the statistical analysis, the risk ratio, standard mean difference, and 95% confidence interval (CI) were used to calculate effect sizes between groups. To determine heterogeneity, statistical index I² was used.

Results

A total of 363 PD participants in seven RCTs and one randomized pilot-control study were included in this meta-analysis. The total effectiveness showed that therapeutic massage was more effective than the intervention of the control group for improving MS [ratio risk (RR): 1.33, 95% CI (1.14–1.55), p = 0.0002]. The UPDRS-III scores showed that massage improves motor function more than the control group [SMD = −0.46, 95% CI (−0.67, −0.24), p < 0.00001]. But we found that massage performed no better than the control group in improving daily life activities [SMD = −0.15, 95% CI (−0.40, 0.10), p = 0.23].

Conclusion

Therapeutic massage was effective in improving MS in PD. It is suggested to be an appropriate form of CAM in treating PD.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=323182, identifier: CRD42022323182.

Effects of tandem walk and cognitive and motor dual- tasks on gait speed in individuals with chronic idiopathic neck pain: a preliminary study

Introduction: Gait impairment has been associated with neck pain. It is relevant to understand the possible influence of narrow-based walk and an attention-demanding secondary task on gait performance in neck pain.Purpose: To investigate the effects of tandem walk and cognitive and motor dual-tasks on gait speed in persons with chronic idiopathic neck pain (CINP) compared with controls.Methods: A cross-sectional study. Thirty participants with CINP and 30 asymptomatic controls participated in the study. Gait speed was assessed using a timed 10-m walk test at a comfortable pace under four conditions: (1) comfortable walk (as reference); (2) tandem walk (single task); (3) cognitive dual-task walking; and (4) motor dual-task walking. Dual-task interference was calculated.Results: There was no difference in comfortable gait speed between groups (p= 0.40). The CINP group had slower gait speed during the tandem walk than controls (p= 0.02). The dual-task interference on gait speed was not different between groups (p = 0.67 for cognitive, p = 0.93 for motor).Conclusion: Participants with CINP had impaired gait stability during tandem walk. An attention-demanding secondary task did not influence gait speed in individuals with CINP compared to controls. The study suggests that tandem walk could be considered as an assessment tool and part of rehabilitation for neck pain.

Neck muscle vibration produces diverse responses in balance and gait speed between individuals with and without neck pain

BACKGROUND

Neck muscle vibration can influence cervical proprioception and sensorimotor function. It is hypothesized to affect motor performance differently in persons with and without neck pain.

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To clarify the extent to which vibration-induced motor responses of neck muscles affect static standing balance and gait speed in persons with and without neck pain.

METHODS

Thirty participants with chronic neck pain and 30 healthy controls were recruited. Balance and gait were measured before and after 30 s of suboccipital neck muscle vibration. Balance was measured in a confortable stance with eyes closed using a swaymeter and gait using the timed 10 m walk test.

RESULTS

At baseline, neck pain participants had greater postural sway, particularly in the anterior-posterior direction and slower gait speed than healthy controls (p < 0.001). Immediately after vibration, neck pain participants displayed decreased postural sway, and increased gait speed (p < 0.001). Healthy controls had increased postural sway and decreased gait speed (p < 0.001).

CONCLUSION

Neck muscle vibration improved standing balance and gait speed in participants with neck pain but reduced performance in healthy controls. The study supports the importance of cervical proprioceptive information in postural control. Use of vibration could be considered neck pain patients' rehabilitation.

Disturbance of neck proprioception and feed-forward motor control following static neck flexion in healthy young adults

The highly complex proprioceptive system provides neuromuscular control of the mobile cervical spine. Static neck flexion can induce the elongation of posterior tissues and altered afferent input from the mechanoreceptors. The purpose of this study was to examine the effect of prolonged static neck flexion on neck proprioception and anticipatory postural adjustments. Thirty-eight healthy participants (20 females and 18 males) between the ages of 20-35 years with no history of neck, low back, and shoulder pain enrolled in this study. Neck proprioception and anticipatory muscle activity were tested before and after 10-min static neck flexion. For assessment of neck proprioception, each participant was asked to perform 10 trials of the cervicocephalic relocation test to the neutral head position after active neck rotation to the left and right sides. Anticipatory postural adjustments were evaluated during a rapid arm flexion test. Following the flexion, the absolute and variable errors in head repositioning significantly increased (p < 0.05). The results also showed that there was a significant delay in the onset of myoelectric activity of the cervical erector spinae muscles after flexion (p = 0.001). The results of this study suggested that a 10-min static flexion can lead to changes in the neck proprioception and feed-forward control due to mechanical and neuromuscular changes in the viscoelastic cervical spine structures. These changes in sensory-motor control may be a risk factor for neck pain and injury.

Effectiveness of Anma massage therapy in alleviating physical symptoms in outpatients with Parkinson's disease: a before-after study

We aimed to confirm the physical effects of a single Anma massage session and continuous Anma massage therapy for outpatients with Parkinson's disease (PD). Twenty-one PD outpatients (mean age, 64.43 ± 8.39 [SD] years; Hoehn and Yahr stage I-IV) received a single 40-min Anma massage session involving upper and lower limb exercises and some subsequently received seven weekly Anma massage sessions. After a single session, visual analogue scale scores were significantly lower for muscle stiffness, movement difficulties, pain, and fatigue; gait speed and pegboard test time were significantly shortened; stride length was significantly lengthened; and shoulder flexion and abduction were significantly improved. No significant changes occurred in controls. After continuous sessions, we found general improvements in the same outcomes. In conclusion, Anma massage might effectively alleviate various physical PD symptoms; furthermore, because it is given through clothing, Anma massage is accessible for PD patients with movement difficulties.

Postural control in response to an external perturbation: effect of altered proprioceptive information

The purpose of the study was to investigate the role of altered proprioception on anticipatory (APAs) and compensatory (CPAs) postural adjustments and their interaction. Nine healthy adults were exposed to external perturbations induced at the shoulder level while standing with intact or altered proprioception induced by bilateral Achilles tendon vibration. Visual information was altered (eyes open or closed) in both the conditions. Electrical activity of eight trunk and leg muscles and center of pressure (COP) displacements were recorded and quantified within the time intervals typical for APAs and CPAs. The results showed that when proprioceptive information was altered in eyes-open conditions, anticipatory muscle activity was delayed. Moreover, altered proprioceptive information resulted in smaller magnitudes of compensatory muscle activity as well as smaller COP displacements after the perturbation in both eyes-open and eyes-closed conditions. The outcome of the study provides information on the interaction between APAs and CPAs in the presence of altered proprioception.

Avaliação dos distúrbios do controle sensório-motor em pessoas com dor cervical mecânica: uma revisão

INTRODUÇÃO: A dor cervical mecânica é problema comum na população em geral e engloba a dor cervical aguda, as lesões em chicote, as disfunções cervicais e a dor cervical-ombro. A limitação da amplitude de movimento, a sensação de aumento da tensão muscular, a cefaleia, a braquialgia, a vertigem e outros sinais e sintomas são manifestações comuns e podem ser agravados por movimentos ou pela manutenção de posturas da coluna cervical. Estudos recentes mostram comprometimento no controle sensório-motor em pessoas com dor cervical manifestando-se por alterações da cinestesia cervical com dificuldade no reconhecimento da posição da cabeça, do movimento dos olhos e do equilíbrio. OBJETIVOS: Descrever, com base na revisão da literatura, as manifestações e os métodos de avaliação dos distúrbios sensório-motores relacionados à dor cervical mecânica. MÉTODOS: Para a revisão foram utilizadas as bases de dados de literatura científica indexada no período de 1965 a 2009. Considerou-se para a inclusão os artigos que abordassem a dor cervical mecânica e os distúrbios da propriocepção cervical, da coordenação dos movimentos dos olhos e do equilíbrio. Não houve restrição quanto à língua de publicação. O processo de seleção foi realizado por dois examinadores independentes, considerando a evidência científica em ordem decrescente, havendo preferência para as meta-análises e os estudos randomizados controlados. RESULTADOS: Dos 119 artigos encontrados, 69 preenchiam os critérios de inclusão. DISCUSSÃO: A presença de alterações dos músculos e das articulações cervicais, o processo de envelhecimento e a presença de dor cervical são descritos como fatores que alteram o sistema somatossensorial cervical e devem ser considerados também como perpetuantes. CONCLUSÃO: As alterações dos sistemas visual, do equilíbrio e proprioceptivo não podem ser desprezadas e devem ser consideradas durante a avaliação fisioterapêutica dos distúrbios cervicais, visto que existe uma integração entre os sistemas.

Sensorimotor function and dizziness in neck pain: implications for assessment and management

SYNOPSIS

The term sensorimotor describes all the afferent, efferent, and central integration and processing components involved in maintaining stability in the postural control system through intrinsic motor-control properties. The scope of this paper is to highlight the sensorimotor deficits that can arise from altered cervical afferent input. From a clinical orthopaedic perspective, the peripheral mechanoreceptors are the most important in functional joint stability; but in the cervical region they are also important for postural stability, as well as head and eye movement control. Consequently, conventional musculoskeletal intervention approaches may be sufficient only for patients with neck pain and minimal sensorimotor proprioceptive disturbances. Clinical experience and research indicates that significant sensorimotor cervical proprioceptive disturbances might be an important factor in the maintenance, recurrence, or progression of various symptoms in some patients with neck pain. In these cases, more specific and novel treatment methods are needed which progressively address neck position and movement sense, as well as cervicogenic oculomotor disturbances, postural stability, and cervicogenic dizziness. In this commentary we review the most relevant theoretical and practical knowledge on this matter and implications for clinical assessment and management, and we propose future directions for research.

LEVEL OF EVIDENCE

Level 5.

Rehabilitation program for traumatic chronic cervical pain associated with unsteadiness: a single case study

BACKGROUND

Neck problems are often recurring or chronic. After pain, unsteadiness and balance problems are among the most frequent symptoms reported by chronic neck pain (CNP) patients. Altered sensorimotor control of the cervical spine and sensorimotor integration problems affecting postural control have been observed in CNP patients. Very few data are available regarding the post-intervention effects of rehabilitation programs on postural control in CNP.

CASE PRESENTATION

This is a case study of a traumatic CNP patient (a 45-year old female) with postural unsteadiness who participated in an 8-week rehabilitation program combining therapeutic exercises with spinal manipulative therapy. Pre-intervention data revealed that the postural control system was challenged when postural control sensory inputs were altered, particularly during the head-extended-backward condition. Post-intervention centre of pressure measurements indicated a drastic reduction in postural sway during trials with changes in neck orientation.

CONCLUSION

This case report indicates that an 8-week rehabilitation program combining therapeutic exercises with spinal manipulative therapy may have had an effect on improvement of postural control in a trauma CNP patient with unsteadiness. These results warrant further studies to investigate the relationships between pain amelioration, sensorimotor control of the cervical spine, muscle fitness and postural steadiness.

The influence of neck pain on balance and gait parameters in community-dwelling elders

Neck pain has been shown to be associated with balance disturbances. Balance and gait speed are also known to decline with ageing. The aim of this study was to determine whether the presence of neck pain was associated with a decline in postural stability and gait speed over and above what is expected with normal ageing. Twenty female subjects with idiopathic neck pain and 20 healthy female controls aged between 65 and 82 years were studied. Subjects performed balance tests on a computerised force plate under conditions of eyes open, eyes closed on firm and soft surfaces in comfortable and narrow stance. Sway energy and root mean square (RMS) amplitude of sway were measured. Subjects also undertook a Timed Ten Metre Walk Test, with and without head turning. There were trends for the elderly group with neck pain to have poorer balance than the healthy controls across most balance conditions, although differences were significant only in the following tests; comfortable stance--eyes closed on a firm surface (p=0.02), eyes open on a soft surface (p=0.01); narrow stance--eyes open on a firm surface (p=0.02). In the Timed Ten meter Walk Test, elderly subjects with neck pain had a slower self-selected gait speed (p=0.02) and cadence (p=0.04) in the head turn condition, as well as a longer gait cycle duration both with (p=0.00) and without head turns (p=0.04). The results of this study suggest that neck pain in the elderly may contribute to some disturbance in balance and gait parameters over and above that which occurs with normal ageing.

Standing balance: A comparison between idiopathic and whiplash-induced neck pain

Disturbances of balance have been found both in patients with whiplash-associated disorders and idiopathic neck pain. This study directly compared balance between these groups to determine if neck pain precipitated by trauma resulted in greater or different balance impairments. The study was a comparative, observational design. Thirty subjects with whiplash, 30 with idiopathic neck pain and 30 healthy controls, took part in the study. Subjects performed balance tests in comfortable, narrow and tandem stances. Balance disturbances (sway energy and/or root mean squared (RMS) amplitude) were evident in several tests between subjects with neck pain and controls. Direct comparison between the neck pain groups revealed that the whiplash group had significantly greater sway energy and RMS amplitude than the idiopathic group in comfortable stance tests on a soft surface (F > 4.4, p < 0.04). Further, the whiplash group had greater RMS, but significantly less sway energy than the idiopathic group in most narrow stance tests in the anterior posterior direction F > 5.8, p < 0.02). Both neck pain groups were also significantly less able to complete the eyes closed, tandem test compared to control subjects. In conclusion, the study has found that balance deficits exist in both subjects with whiplash-associated disorders and idiopathic neck pain compared to controls; however, differences in balance strategies may exist between the neck pain groups. Overall, subjects who have experienced trauma appear to have greater balance disturbances.

Sensorimotor disturbances in neck disorders affecting postural stability, head and eye movement control

The receptors in the cervical spine have important connections to the vestibular and visual apparatus as well as several areas of the central nervous system. Dysfunction of the cervical receptors in neck disorders can alter afferent input subsequently changing the integration, timing and tuning of sensorimotor control. Measurable changes in cervical joint position sense, eye movement control and postural stability and reports of dizziness and unsteadiness by patients with neck disorders can be related to such alterations to sensorimotor control. It is advocated that assessment and management of abnormal cervical somatosensory input and sensorimotor control in neck pain patients is as important as considering lower limb proprioceptive retraining following an ankle or knee injury. Afferent information from the cervical receptors can be altered via a number of mechanisms such as trauma, functional impairment of the receptors, changes in muscle spindle sensitivity and the vast effects of pain at many levels of the nervous system. Recommendations for clinical assessment and management of such sensorimotor control disturbances in neck disorders are presented based on the evidence available to date.

Stance- and Locomotion-Dependent Processing of Vibration-Induced Proprioceptive Inflow From Multiple Muscles in Humans

We performed a whole-body mapping study of the effect of unilateral muscle vibration, eliciting spindle Ia firing, on the control of standing and walking in humans. During quiet stance, vibration applied to various muscles of the trunk-neck system and of the lower limb elicited a significant tilt in whole body postural orientation. The direction of vibration-induced postural tilt was consistent with a response compensatory for the illusory lengthening of the stimulated muscles. During walking, trunk-neck muscle vibration induced ample deviations of the locomotor trajectory toward the side opposite to the stimulation site. In contrast, no significant modifications of the locomotor trajectory could be detected when vibrating various muscles of the lower as well as upper limb. The absence of correlation between the effects of muscle vibration during walking and standing dismisses the possibility that vibration-induced postural changes can account for the observed deviations of the locomotor trajectory during walking. We conclude that the dissimilar effects of trunk-neck and lower limb muscle vibration during walking and standing reflect a general sensory-motor plan, whereby muscle Ia input is processed according to both the performed task and the body segment from which the sensory inflow arises.

Coordinated modulation of locomotor muscle synergies constructs straight-ahead and curvilinear walking in humans

We describe the muscle synergies accompanying steering of walking along curved trajectories, in order to analyze the simultaneous control of progression and balance-threatening emerging forces. For this purpose, we bilaterally recorded in ten subjects the electromyograms (EMGs) of a representative sample of leg and trunk muscles (n=16) during continuous walking along one straight and two curved trajectories at natural speed. Curvilinear locomotion involved a graded, limb-dependent modulation of amplitude and timing of activity of the muscles of the legs and trunk. The turn-related modulation of the motor pattern was highly coordinated amongst muscles and body sides. For all muscles, linear relationships were detected between the spatial and temporal features of muscle EMG activity. The largest modulation of EMG was observed in gastrocnemius medialis and lateralis muscles, which showed opposite changes in timing and amplitude during curve-walking. Moreover, amplitude and timing characteristics of muscle activities were significantly correlated with the spatial and temporal gait adaptations that are associated with curvilinear locomotion. The present results reveal that fine-modulation of the muscle synergies underlying straight-ahead locomotion is enough to generate the adequate propulsive forces to steer walking and maintain balance. These findings suggest that the turn-related command operates by modulation of the phase relationships between the tightly coupled neuronal assemblies that drive motor neuron activity during walking. This would produce the invariant templates for locomotion kinematics that are at the base of human navigation in space.

Postural responses and spatial orientation to neck proprioceptive and vestibular inputs during locomotion in young and older adults

Both vestibular and neck proprioceptive inputs contribute towards maintaining a walking trajectory. We investigated how aging alters neck proprioceptive and vestibular interaction for preserving equilibrium and spatial orientation during locomotion. Young and healthy elderly were exposed to two sensory manipulations as they walked, eyes closed, to a target located straight ahead: (1) right side dorsal neck muscle vibration (Vib), and (2) Vib + transmastoidal galvanic vestibular stimulation (Vib + GVS). The maximum path deviation, average frontal centre of mass velocity and average trunk roll were evaluated. Trunk yaw rotation was computed at every metre of the path. We observed that directional responses to neck muscle stimulation were very sensitive to the reference frame generated by vestibular information. The attenuation of path deviation in older adults can be attributed to a reduced sensitivity of the neck proprioceptive system rather than the vestibular system.