Cervico-ocular coordination during neck rotation is distorted in people with whiplash-associated disorders

Reliability of Rehabilitative Musculoskeletal Sonography for Measuring the Visible Cross-Sectional Area of Suboccipital Muscles

Aims The primary aim of this study is to assess the reliability of rehabilitative sonography as a non-invasive imaging technique for measuring the visible cross-sectional area (CSA) of the deep suboccipital muscles. Objectives Objectives involve determining both the intra-rater and inter-rater reliability of sonographic measurements to ensure consistent and reproducible results across different sessions and examiners. The ultimate goal is to validate rehabilitative sonography as a reliable tool for clinical and research applications in the assessment and management of musculoskeletal (MSK) conditions involving the deep suboccipital muscles. Design and setting Seventeen participants, including nine women and eight men without neck or vertebral pain, were evaluated using MSK sonography. The visible CSA of suboccipital muscles was assessed using real-time B-mode sonography in a sitting position with a linear probe (5 cm, 7.5 MHz) aligned perpendicularly to the muscle fibers of the rectus capitis posterior minor (RCPM) in one sonogram and the obliquus capitis inferior (OCI) and rectus capitis posterior major (RCPMJ) in another. Two experienced examiners performed sonography measurements, and the procedure was repeated one hour and again one day later. Results Intra-class correlation coefficient (ICC) values for Examiner 1 were 0.84 and 0.79 for RCPM, 0.84 and 0.71 for RCPMJ, and 0.86 and 0.77 for OCI at the one-hour and one-day repetitions, respectively. ICC values for Examiner 2 were 0.86 and 0.77 for RCPM, 0.77 and 0.86 for RCPMJ, and 0.61 and 0.64 for OCI at the one-hour and one-day repetitions, respectively. Inter-rater ICC values were 0.77 for RCPM, 0.82 for RCPMJ, and 0.68 for OCI. Standard error of measurement (SEM) values for Examiner 1 were 11.63 and 13.92 mm² for RCPM, 10.30 and 7.91 mm² for RCPMJ, and 22.84 and 34.61 mm² for OCI. SEM values for Examiner 2 were 11.82 and 13.40 mm² for RCPM, 11.91 and 7.04 mm² for RCPMJ, and 39.20 and 37.73 mm² for OCI. SEM values between examiners were 13.74 mm² for RCPM, 10.36 mm² for RCPMJ, and 36.03 mm² for OCI. Conclusions These findings suggest that sonography is a reliable method for measuring the CSA of the RCPM, RCPMJ, and OCI muscles, provided that the examiners are well-trained and consistent in their techniques and that the average of three measurements is used.

Neck muscle function improves after neck exercises in individuals with whiplash-associated disorders: a case-control ultrasound study with speckle-tracking analyses

A whiplash injury can alter neck muscle function, which remains years after the injury and may explain why symptoms such as persistent pain and disability occur. There is currently limited knowledge about dynamic neck muscle function in chronic whiplash-associated disorders (WAD), and about the extent to which altered muscle function can improve after rehabilitation. Ultrasound can detect mechanical neck muscle function by measuring real-time deformation and deformation rate in the muscles. This method was used for five dorsal neck muscles in participants with chronic WAD versus matched controls in resistant neck rotation. We obtained real-time, non-invasive ultrasound measurements using speckle tracking, multivariate analyses, and mixed-design ANOVA analyses. The results showed altered deformation in the three deepest neck muscle layers, with less deformation area in the WAD group compared to controls in rotation to the most painful side at baseline. Participants in the WAD group performed three months of neck-specific exercises, resulting in improved deformation in the deep neck muscles in WAD and with a similar deformation pattern to controls, and the significant group differences ceased. We reveal new and important insights into the capability of ultrasound to diagnose altered neck muscle function and evaluate an exercise intervention.

Neck muscle activation in response to eye movement depends on sitting posture and is modified in whiplash associated disorders: Cross-sectional study

BACKGROUND

Activity of specific neck muscles is modulated by eye movement. This activity modulation is exaggerated in people with whiplash associated disorders (WAD), but it is unknown whether it is impacted by sitting posture.

OBJECTIVE

This study investigated; (i) whether activity of cervical muscles differs with spinal posture; (ii) whether the effect of eye gaze direction (horizontal/vertical) on neck muscle activity differs between postures, and (iii) whether these effects differ between individuals with and without WAD.

METHODS

In three seated postures (normal relaxed, head forward, sit tall) electromyography (EMG) was recorded right obliquus capitis inferior (OI), multifidus (MF), splenius capitis (SP) and left sternocleidomastoid (SCM) with fine-wire and surface electrodes in ten healthy controls and nine with WAD. Electro-oculography recorded eye movements.

RESULTS

In controls, EMG was less for extensor muscles in Sit Tall than Head Forward, but higher in SCM. Only SC EMG modulated with eye movement. When WAD participants adopted similar sitting postures several responses were different; compared to Normal Relaxed posture OI EMG was less in Head Forward; MF EMG was less in Sit Tall; and SC was less in Head Forward and Sit Tall. Neck muscles in WAD were generally more sensitive to eye movement, except SC which did not modulate.

CONCLUSIONS

These finding support the hypothesis that neck muscle activity is influenced by spinal posture and eye movement. In WAD, this relationship is distorted and the response to eye movement is increased.

SIGNIFICANCE

These observations have potential implications for clinical management of individuals with WAD.

Deep and superficial cervical muscles respond differently to unstable motor skill tasks

Biomechanical modelling and physiological studies suggest that various spinal muscle layers differ in their contribution to spine movement and stiffness. This study aimed to investigate the activation of deep and superficial muscles in stable and unstable task conditions. Nine healthy participants performed a task of controlling a metal ball on a plate fixed to the head in seated position. In unstable tasks, visual feedback was provided by mirrors to move the ball to the centre of the plate by small head movements and maintain the position for 3 s. Task difficulty was adjusted in a stepwise progression of difficulty using five surfaces with materials of decreasing resistance. In the stable condition, the ball was fixed to the plate's centre. EMG was recorded with surface (sternocleidomastoid, anterior scalenes, upper trapezius) and fine-wire electrodes (rectus capitis posterior major, obliquus inferior, multifidus, semispinalis cervicis, splenius capitis). The outcome variable was root mean square (RMS) EMG during the part of the task when the ball was maintained in the centre position. Results revealed greater cervical muscle activity in the unstable than stable conditions (p < 0.001, η_p² = 0.746). Control of deep and superficial cervical muscles differed (p = 0.003, η_p² = 0.354). Deep cervical muscle activity was greater with unstable tasks, but did not differ with task difficulty. In contrast, superficial cervical muscle activity increased in a stepwise manner with increasing challenge. These results support the notion that the central nervous system uses different strategies for control of deep versus superficial muscle layers of the cervical spine in association with instability.

Smooth Pursuit Eye-Movement Abnormalities Associated With Cervical Spine Whiplash: A Scientific Review and Case Report

Whiplash injuries may disrupt normal cervical afferent and efferent projections. Oculomotor abnormalities have been reported in chronic whiplash cases, but there is limited knowledge of their presence in acute whiplash and how acute assessment may target early intervention. We present a literature review and case study of a 22-year-old female presenting with an acute concussion and whiplash secondary to a high-speed motor vehicle collision. Smooth pursuit eye-movement abnormalities were observed in relative cervical rotation in the setting of clinical examination of cervicogenic dysfunction. Treatment was focused on cervical manual therapy. While concussive symptoms resolved after seven days, eye-tracking showed a mild improvement and continued to exist in relationship with cervicogenic dysfunction. After completing physical therapy twice weekly for two weeks and in-home exercises, clinical signs and symptoms of whiplash-associated cervicogenic dysfunction and abnormal smooth pursuit eye-movement resolved across all cervical positions. This case highlights the need for ocular-motor impairment assessment following acute whiplash, specifically during cervical rotation. Early intervention should focus on cervical manual therapy and may be important in supporting altered cervical afferents causing oculomotor dysfunctions following acute whiplash.

A pilot study on the evaluation of eye, head, and trunk coordination in subjects with chronic whiplash during a target-tracking task - A driving context approach

BACKGROUND

Motor vehicle accidents (MVA) are the most common causes of whiplash injuries. Difficulties with driving and changes in driving behavior are reported by subjects with chronic whiplash associated disorders (WAD). Proper eye and head coordination is required for driving tasks. Disturbances of eye and head coordination were found in these subjects with chronic WAD.

OBJECTIVES

The objective of this pilot study is to evaluate eye, head and trunk coordination in subjects with chronic WAD due to MVA and healthy controls during a target-tracking task using a functionally oriented approach in the context of driving.

DESIGN

Cross-sectional.

METHOD

The subjects performed target tracking tasks that reproduced eye and head movements required while driving. Head and trunk motion was captured using a motion capture system and eye movement was captured with an eye-tracker. Response time, time to target, and eye, head, and trunk contribution of movement were measured.

RESULTS/FINDINGS

Subjects with chronic WAD presented delayed response time and time to reach the targets with both eyes and head compared to the control group, and tended to compensate the lack of neck motion with increased eye motion.

CONCLUSIONS

This study shows indications of impairments of eye and head coordination in chronic WAD due to MVA when compared to healthy subjects. These alterations may have implications for driving safety.

Cervical Rotator Muscle Activity With Eye Movement at Different Speeds is Distorted in Whiplash

BACKGROUND

People with whiplash-associated disorders (WADs) report difficulty with quick head movements and cervicoocular dysfunction. Changes in coordination between eye movement and neck muscle activity may be involved.

OBJECTIVE

To examine whether activity of superficial and deep neck muscles increases with eye movement when the head is held in a fixed position, whether this differs between directions and speed of eye movement, and whether this is modified in WAD.

DESIGN

Convenience case series with unmatched controls.

SETTING

Research laboratory.

PARTICIPANTS

Nine individuals with chronic WAD grade II and 11 pain-free controls.

METHODS

Electromyography (EMG) was recorded from muscles that could act to rotate the neck to the right (right obliquus capitis inferior [OI], multifidus [MF], splenius capitis [SC], and left sternocleidomastoid [SCM]) with intramuscular or surface electrodes in 9 WAD participants and 11 pain-free controls. Eyes were rotated without head movement to track slow and medium-speed targets to the right or left, and as fast as possible (FP).

MAIN OUTCOME MEASUREMENTS

Amplitude of EMG.

RESULTS

In controls, SCM and SC EMG increased with right gaze (all P's < .03). EMG of the deep OI muscle increased in both directions (P < .001). WAD involved counterintuitive greater activity of SCM with left rotation across speeds of eye movement (SC with slow movement, P < .036), decreased OI EMG with gaze left (P < .019), and no change in MF EMG (P < .6) in either gaze direction. For FP tasks, EMG of all muscles was greater than slower speeds in controls (all P's < .0001), but not WAD (all P's > .33).

CONCLUSIONS

Coordination between neck muscle activity and eye movements with increasing speed is modified in WAD. Contrasting changes are present in deep and superficial neck muscles with implications for neck function that may explain some common WAD symptoms.

LEVEL OF EVIDENCE

IV.

Effects of deep cervical flexor training on impaired physiological functions associated with chronic neck pain: a systematic review

Background

Neck pain is a major health issue with high rates of recurrence. It presents with a variety of altered sensorimotor functions. Exercise is a cornerstone of rehabilitation and many training methods are used. Exercise is evaluated in most randomized controlled trials on its pain relieving effects. No review has assessed the effect of exercise on the altered physiological functions or determined if there are differential effects of particular training methods. This review investigated the effects of deep cervical flexor (DCF) training, a training method commonly used for patients with neck pain, and compared it to other training methods or no training on outcomes of cervical neuromuscular function, muscle size, kinematics and kinetics.

Methods

Web of Science, Scopus, CINAHL, PubMed were searched from inception until January 2018. Twelve randomized controlled trials were included that compared DCF training as sole intervention to other training or no interventions in persons with neck pain. The Cochrane Risk of Bias tool was used to assess the method quality. All outcome measures were analysed descriptively and meta-analyses were performed for measures evaluated in three or more studies.

Results

DCF training was compared to cervical endurance, strength, proprioception and mobility training, muscle stretching, and no intervention control groups. Physiological outcome measures included neuromuscular co-ordination (craniocervical flexion test), functional tasks, muscle fatigability, muscle size, kinematics (joint position sense, posture and range of motion) and kinetics (strength, endurance and contraction accuracy). Strong evidence was found for effectiveness of DCF training on neuromuscular coordination, but it had no or small effects on strength and endurance at higher loads. DCF training improved head and cervical posture, while evidence was limited or contradictory for other measures.

Conclusions

DCF training can successfully address impaired neuromuscular coordination, but not cervical flexor strength and endurance at higher contraction intensities. A multimodal training regime is proposed when the aim is to specifically address various impaired physiological functions associated with neck pain.

Temporomandibular disorder and comorbid neck pain: facts and hypotheses regarding pain-induced and rehabilitation-induced motor activity changes

According to the "pain adaptation model", temporomandibular disorder (TMD)-related pain induces a paradoxical activity of masticatory muscles: an agonistic hypoactivity during jaw closing and an antagonistic activity during jaw opening (agonist/antagonist co-activation). However, this model suffers several weaknesses; notably, it does not explain all types of neck muscle activities in neck pain (NP), which is a very prevalent TMD comorbid condition. In NP, neck muscle antagonistic activity is increased, and agonistic activity is decreased as postulated by the pain adaptation model. However, synergistic and compensatory activity may occur and agonistic activity may be unchanged or even increased as postulated within the "vicious cycle theory". Thus, both theories would apply partly as outlined currently in musculoskeletal disorders (MSD). Besides pain, psychological stress may also induce motor dysfunction in TMD and NP. In NP, rehabilitation may increase agonistic activity and decrease compensatory activity and antagonistic activity, thus inducing a switch from agonist/antagonist co-activation towards reciprocal inhibition. Thus, rehabilitation-induced motor activity changes constitute a new research field that should improve MSD therapeutics. Additionally, immature tongue function (so-called infantile swallow) might be connected to TMD where low agonistic activity of masticatory muscles would be compensated by facial muscle hyperactivity during oropharyngeal phase of deglutition.

The influence of cervical movement on eye stabilization reflexes: a randomized trial

To investigate the influence of the amount of cervical movement on the cervico-ocular reflex (COR) and vestibulo-ocular reflex (VOR) in healthy individuals. Eye stabilization reflexes, especially the COR, are changed in neck pain patients. In healthy humans, the strength of the VOR and the COR are inversely related. In a cross-over trial the amplitude of the COR and VOR (measured with a rotational chair with eye tracking device) and the active cervical range of motion (CROM) was measured in 20 healthy participants (mean age 24.7). The parameters were tested before and after two different interventions (hyperkinesia: 20 min of extensive active neck movement; and hypokinesia: 60 min of wearing a stiff neck collar). In an additional replication experiment the effect of prolonged (120 min) hypokinesia on the eye reflexes were tested in 11 individuals. The COR did not change after 60 min of hypokinesia, but did increase after prolonged hypokinesia (median change 0.220; IQR 0.168, p = 0.017). The VOR increased after 60 min of hypokinesia (median change 0.155, IQR 0.26, p = 0.003), but this increase was gone after 120 min of hypokinesia. Both reflexes were unaffected by cervical hyperkinesia. Diminished neck movements influences both the COR and VOR, although on a different time scale. However, increased neck movements do not affect the reflexes. These findings suggest that diminished neck movements could cause the increased COR in patients with neck complaints.

Alterations in the Mechanical Response of Deep Dorsal Neck Muscles in Individuals Experiencing Whiplash-Associated Disorders Compared to Healthy Controls: An Ultrasound Study

OBJECTIVE

The aim of this study was to investigate and compare the mechanical responses of dorsal neck muscles in individuals with whiplash-associated disorders (WAD) versus healthy individuals.

DESIGN

This study included 36 individuals with WAD (26 women and 10 men) and 36 healthy controls (26 women and 10 men). Ultrasound imaging with speckle tracking was used to measure deformation and deformation rate in five dorsal neck muscles during a neck extension task.

RESULTS

Compared with controls, individuals with WAD showed higher deformations of the semispinalis cervicis (P = 0.02) and multifidus (P = 0.002) muscles and higher deformation rates (P = 0.03 and 0.0001, respectively). Among individuals with WAD, multifidus deformation and deformation rate were significantly associated with pain, disability, and fatigue (r = 0.31-0.46, P = 0.0001-0.01).

CONCLUSIONS

These findings indicate that the mechanical responses of the deep dorsal neck muscles differ between individuals with WAD and healthy controls, possibly reflecting that these muscles use altered strategies while performing a neck extension task. This finding provides new insight into neck muscles pathology in patients with chronic WAD and may help improve rehabilitation programs.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) Summarize the mechanical responses of dorsal neck muscles during loading of the neck muscles via an extension task in individuals with chronic whiplash associated disorders and healthy volunteers; (2) Differentiate mechanical responses between five dorsal neck muscles while loading the neck via an extension task; and (3) Describe the relationships between the mechanical responses of the dorsal neck muscles with the patients' perception of neck pain, disability, and fatigue.

LEVEL

Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 0.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Dizziness, Unsteadiness, Visual Disturbances, and Sensorimotor Control in Traumatic Neck Pain

Synopsis There is considerable evidence to support the importance of cervical afferent dysfunction in the development of dizziness, unsteadiness, visual disturbances, altered balance, and altered eye and head movement control following neck trauma, especially in those with persistent symptoms. However, there are other possible causes for these symptoms, and secondary adaptive changes should also be considered in differential diagnosis. Understanding the nature of these symptoms and differential diagnosis of their potential origin is important for rehabilitation. In addition to symptoms, the evaluation of potential impairments (altered cervical joint position and movement sense, static and dynamic balance, and ocular mobility and coordination) should become an essential part of the routine assessment of those with traumatic neck pain, including those with concomitant injuries such as concussion and vestibular or visual pathology or deficits. Once adequately assessed, appropriate tailored management should be implemented. Research to further assist differential diagnosis and to understand the most important contributing factors associated with abnormal cervical afferent input and subsequent disturbances to the sensorimotor control system, as well as the most efficacious management of such symptoms and impairments, is important for the future. J Orthop Sports Phys Ther 2017;47(7):492-502. Epub 16 Jun 2017. doi:10.2519/jospt.2017.7052.

Cervical spine reposition errors after cervical flexion and extension

BACKGROUND

Upright head and neck position has been frequently applied as baseline for diagnosis of neck problems. However, the variance of the position after cervical motions has never been demonstrated. Thus, it is unclear if the baseline position varies evenly across the cervical joints. The purpose was to assess reposition errors of upright cervical spine.

METHODS

Cervical reposition errors were measured in twenty healthy subjects (6 females) using video-fluoroscopy. Two flexion movements were performed with a 20 s interval, the same was repeated for extension, with an interval of 5 min between flexion and extension movements. Cervical joint positions were assessed with anatomical landmarks and external markers in a Matlab program. Reposition errors were extracted in degrees (initial position minus reposition) as constant errors (CEs) and absolute errors (AEs).

RESULTS

Twelve of twenty-eight CEs (7 joints times 4 repositions) exceeded the minimal detectable change (MDC), while all AEs exceeded the MDC. Averaged AEs across the cervical joints were larger after 5 min' intervals compared to 20 s intervals (p < 0.05).

CONCLUSIONS

This is the first study to demonstrate single joint reposition errors of the cervical spine. The cervical spine returns to the upright positions with a 2° average absolute difference after cervical flexion and extension movements in healthy adults.

Evaluation of eye, head and trunk coordination during target tracking tasks

This study tested the feasibility of a method to synchronise and to evaluate eye, head and trunk movement patterns during target tracking tasks performed by 10 subjects. A projected central target was randomly repositioned at 40° and 70° of rotation to the left and right. Subjects were instructed to change gaze as quickly as possible. Head and trunk motion was measured using a motion analysis system, and eye movement was measured using an eye-tracker; all data were synchronised. For healthy subjects, the eye moved faster than the head, there was no trunk movement and the head moved more than the eye to reach further displaced targets. The method tested was feasible, and it could be used to evaluate eye, head and trunk movement patterns of subjects with injuries such as whiplash and concussions. Practitioner Summary: Studies of eye, head and trunk movements using synchronised methods are needed. We tested the feasibility of a method to synchronise and evaluate eye, head and trunk movement patterns. The method tested was feasible, and it could be used to evaluate movement patterns of subjects with injuries such as whiplash.

Eye movements in patients with Whiplash Associated Disorders: a systematic review

Background

Many people with Whiplash Associated Disorders (WAD) report problems with vision, some of which may be due to impaired eye movements. Better understanding of such impaired eye movements could improve diagnostics and treatment strategies.

This systematic review surveys the current evidence on changes in eye movements of patients with WAD and explains how the oculomotor system is tested.

Methods

Nine electronic data bases were searched for relevant articles from inception until September 2015. All studies which investigated eye movements in patients with WAD and included a healthy control group were screened for inclusion. Qualifying studies were retrieved and independently assessed for methodological quality using the Methodology Checklists provided by the Scottish Intercollegiate Guidelines Network.

Results

Fourteen studies out of 833 unique hits were included. Ten studies reported impaired eye movements in patients with WAD and in four studies no differences compared to healthy controls were found. Different methods of eye movement examination were used in the ten studies: in five studies, the smooth pursuit neck torsion test was positive, in two more the velocity and stability of head movements during eye-coordination tasks were decreased, and in another three studies the cervico-ocular reflex was elevated.

Conclusions

Overall the reviewed studies show deficits in eye movement in patients with WAD, but studies and results are varied. When comparing the results of the 14 relevant publications, one should realise that there are significant differences in test set-up and patient population. In the majority of studies patients show altered compensatory eye movements and smooth pursuit movements which may impair the coordination of head and eyes.

Changes in Dorsal Neck Muscle Function in Individuals with Chronic Whiplash-Associated Disorders: A Real-Time Ultrasound Case-Control Study

Impaired neck muscle function leads to disability in individuals with chronic whiplash-associated disorder (WAD), but diagnostic tools are lacking. In this study, deformations and deformation rates were investigated in five dorsal neck muscles during 10 arm elevations by ultrasonography with speckle tracking analyses. Forty individuals with chronic WAD (28 women and 12 men, mean age = 37 y) and 40 healthy controls matched for age and sex were included. The WAD group had higher deformation rates in the multifidus muscle during the first (p < 0.04) and 10th (only women, p < 0.01) arm elevations compared with the control group. Linear relationships between the neck muscles for deformation rate (controls: R(2) = 0.24-0.82, WAD: R(2) = 0.05-0.74) and deformation of the deepest muscles (controls: R(2) = 0.61-0.32, WAD: R(2) = 0.15-0.01) were stronger for women in the control group versus women with WAD, indicating there is altered interplay between dorsal neck muscles in chronic WAD.

A 1-Diopter Vertical Prism Induces a Decrease of Head Rotation: A Pilot Investigation

Clinical studies in non-specific chronic arthralgia and back pain seem to indicate an association between vertical heterophoria (VH - latent vertical retinal misalignment) and asymmetrical head rotation. Such clinical observations suggest a link between VH and head rotation, but this was never tested. The purpose of this study was to simulate a VH in healthy subjects and examine its influence on the amplitude of active head rotation during 3D motion capture in upright stance. Subjects were asked to rotate their head three times from the straight ahead position and then to the right, back to straight ahead, to the left, and back to the straight ahead again. Three randomized conditions were run: normal viewing, with a 1-diopter prism base down on the dominant eye, or the non-dominant eye. The most important finding is that the experimental VH whichever the eye with the prism induces a significant decrease in the mean angle of head rotation compared to the normal viewing condition. This decrease was significant for rotation to the left. We suggest that the prism-induced VH modifies the reference posture and thereby affects head rotation; further studies are needed to confirm this effect and to extend to other types of dynamic activities.

Novel insights into the interplay between ventral neck muscles in individuals with whiplash-associated disorders

Chronic whiplash-associated disorder (WAD) is common after whiplash injury, with considerable personal, social, and economic burden. Despite decades of research, factors responsible for continuing pain and disability are largely unknown, and diagnostic tools are lacking. Here, we report a novel model of mechanical ventral neck muscle function recorded from non-invasive, real-time, ultrasound measurements. We calculated the deformation area and deformation rate in 23 individuals with persistent WAD and compared them to 23 sex- and age-matched controls. Multivariate statistics were used to analyse interactions between ventral neck muscles, revealing different interplay between muscles in individuals with WAD and healthy controls. Although the cause and effect relation cannot be established from this data, for the first time, we reveal a novel method capable of detecting different neck muscle interplay in people with WAD. This non-invasive method stands to make a major breakthrough in the assessment and diagnosis of people following a whiplash trauma.

Temporal Co-Variation between Eye Lens Accommodation and Trapezius Muscle Activity during a Dynamic Near-Far Visual Task

Near work is associated with increased activity in the neck and shoulder muscles, but the underlying mechanism is still unknown. This study was designed to determine whether a dynamic change in focus, alternating between a nearby and a more distant visual target, produces a direct parallel change in trapezius muscle activity. Fourteen healthy controls and 12 patients with a history of visual and neck/shoulder symptoms performed a Near-Far visual task under three different viewing conditions; one neutral condition with no trial lenses, one condition with negative trial lenses to create increased accommodation, and one condition with positive trial lenses to create decreased accommodation. Eye lens accommodation and trapezius muscle activity were continuously recorded. The trapezius muscle activity was significantly higher during Near than during Far focusing periods for both groups within the neutral viewing condition, and there was a significant co-variation in time between accommodation and trapezius muscle activity within the neutral and positive viewing conditions for the control group. In conclusion, these results reveal a connection between Near focusing and increased muscle activity during dynamic changes in focus between a nearby and a far target. A direct link, from the accommodation/vergence system to the trapezius muscles cannot be ruled out, but the connection may also be explained by an increased need for eye-neck (head) stabilization when focusing on a nearby target as compared to a more distant target.

Clinical and symptomatological reflections: the fascial system

Every body structure is wrapped in connective tissue, or fascia, creating a structural continuity that gives form and function to every tissue and organ. Currently, there is still little information on the functions and interactions between the fascial continuum and the body system; unfortunately, in medical literature there are few texts explaining how fascial stasis or altered movement of the various connective layers can generate a clinical problem. Certainly, the fascia plays a significant role in conveying mechanical tension, in order to control an inflammatory environment. The fascial continuum is essential for transmitting muscle force, for correct motor coordination, and for preserving the organs in their site; the fascia is a vital instrument that enables the individual to communicate and live independently. This article considers what the literature offers on symptoms related to the fascial system, trying to connect the existing information on the continuity of the connective tissue and symptoms that are not always clearly defined. In our opinion, knowing and understanding this complex system of fascial layers is essential for the clinician and other health practitioners in finding the best treatment strategy for the patient.