Research Review By Dr. Demetry Assimakopoulos©

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Date Posted:

November 2018

Study Title:

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

Authors:

Treleaven J

Author's Affiliations:

Neck Pain and Whiplash Research Group, Division of Physiotherapy, School of Health and Rehabilitation Sciences, University of Queensland, Australia.

Publication Information:

Journal of Orthopedic and Sports Physical Therapy 2017; 47(7): 492-502.

Background Information:

Neck pain, headache, dizziness, unsteadiness, visual disturbance, postural instability and altered head and eye movements are just some of the plethora of possible signs and symptoms patients report after neck trauma (including concussion in some cases!). Their presence and coexistence can certainly vary! Understanding the etiology of such disturbances can allow practitioners to more accurately assess and treat these ancillary clinical features that may impede an individual patient’s recovery. Research to date has investigated several suspected causes of these signs and symptoms in neck trauma patients and chief among them is altered sensorimotor control or integration (1). Bearing this in mind, the author of this clinical commentary sought to discuss the evidence surrounding sensorimotor disturbance in the context of neck pain, including its clinical assessment, differential diagnosis, predictors of poor recovery and implications for management.

Summary:

The sensorimotor control system coordinates inputs from the visual, vestibular and proprioceptive systems, cervical spine and central nervous system (CNS) to control head movement, eye movement and postural stability (2). It is theorized that damage or impairment to these individual sub-components is possible after trauma like whiplash. Animal and human models have demonstrated sensorimotor control impairment from relatively low force incidents and direct blows to the head (i.e. there can certainly be some overlap with concussion). Cervical spine afferents provide important input to multiple systems and are involved in several reflexes that affect movement control of the eye and head as well as postural stability.

Disturbances in sensorimotor control after neck trauma are mediated primarily by altered cervical input. Apart from the trauma itself, the factors associated with trauma such as inflammation, functional impairment, changes in muscle morphology, pain and psychological distress may alter cervical afferents or CNS representation (that is, the message itself as well as how that message may be perceived centrally). These factors can then alter cervical reflex connections to the visual and vestibular systems, resulting in secondary disturbances (3). It is theorized that immediate changes in cervical input following neck trauma are common causes of dizziness, visual disturbances and unsteadiness.

Symptoms:

Symptoms of cervicogenic dizziness and unsteadiness are often present in patients following neck trauma, particularly in those with persistent neck pain. True vertigo is rarely reported (which implies “spinning” or a sensation of motion due to an impairment in vestibular function), making ‘cevicogenic dizziness’ the preferred diagnostic term. Cervicogenic dizziness is typically described by patients as unsteadiness and/or light-headedness and can be associated with balance loss or falls (4). Aggravated neck pain, headache or neck-related movements/activities typically exacerbate symptoms (4, 5).

Whiplash and idiopathic neck pain can also present with visual symptoms, typically described as needing to concentrate to read, visual fatigue, difficulty judging distance and light sensitivity (6). These symptoms are also commonly experienced by patients with post-concussive syndrome, who also describe losing their location on a page, ineffective reading speed and even double vision. Other symptoms which overlap between traumatic neck pain and post-concussive syndrome are headache, poor concentration and fatigue. These descriptions raise the possibility of neck trauma occurring alongside head trauma (most concussions involve trauma to the neck, right?), leading to the potential of overlapping symptomatology. It should be noted that true double vision is common in vertebrobasilar insufficiency and is not commonly reported alongside a history of traumatic neck pain (hence, it is worth asking patients specifically about double vision!).

Assessing Cervical Proprioception:

Joint position sense (JPS) is described as the ability to relocate the natural head position without the assistance of vision (7). Greater amounts of joint position sense error are demonstrable in individuals with idiopathic moderate-to-severe neck pain, whiplash and associated disability (8, 9). Patients with persistent WAD and dizziness symptoms tend to have greater JPS error amounts than those without dizziness, suggesting that these symptoms may be secondary to greater aberrant cervical afferent input.

To test for joint position error (and by extension, some degree of vestibular function), the cervical joint position error in neck torsion test was developed. For this test, a laser is placed on the sternum and projected onto a target 90 cm away. The head is held by the practitioner, while the patient actively rotates the trunk as far as possible and then returns to the starting position as accurately as possible with their vision occluded. The difference in degrees between the starting and ending positions is considered the joint position error. While this test has promise in differential diagnosis, further research is required before it can be reliably utilized clinically. Interestingly, errors in joint position have not only been demonstrated in the cervical spine, but also in the shoulder and elbow in some patients with neck pain.

Cervical Movement Accuracy is another measure of neck proprioception and movement control. Several studies (10, 11) demonstrated poorer dynamic and stationary accuracy in tracing a computer-generated movement pattern with the head in traumatic and idiopathic neck pain patients compared to controls. This sort of testing also requires further study.

Vertical Alignment Perception can also be impaired in traumatic or even chronic neck pain patients. This refers to a patient’s ability to identify true vertical using a rod and frame system. At this time, more research is needed to clarify the role of this test.

Assessing Balance:

Several studies have demonstrated postural instability and static balance impairment in traumatic neck pain sufferers, particularly when they also suffer from concomitant dizziness. Balance disturbances have also been related to neck muscle fatigue in whiplash patients (a potentially useful target for rehab?) (12). Deficits have been documented in several testing conditions, including comfortable standing, narrow and tandem stances, but especially when vision is occluded. Sway is usually increased in the AP direction, which is indicative of somatosensory impairment, although other compensations such as stiffening and even less sway have been observed in those with idiopathic neck pain. Such balance disturbances are thought to be secondary to cervical afferent dysfunction rather than vestibular dysfunction (13).

Dynamic and functional balance impairments have also been observed and documented using step tests, 10-m walking, tandem walking and stair walking. Delayed corrective responses to destabilizing perturbations while sitting and stepping in place have also been demonstrated in those with persistent whiplash, but signs may be more apparent in those with traumatic neck pain, with and without concussion. Patients with concomitant concussive symptoms tend to have more extreme balance deficits, possibly suggesting combined cervical/vestibular deficit in this population.

Assessing Eye Movement Control:

Several studies have demonstrated that alterations in eye tracking/motion, gaze stability, eye-head coordination, vergence, saccades and ocular reflex activity are associated with traumatic neck pain, and are theorized to be present in vestibular and CNS disorders as a result of abnormal cervical spinal afferent input (14-16).

Some studies evaluating neck torsion have demonstrated disturbed sensorimotor control secondary to changes in cervical afferent input. Smooth pursuit with neck torsion has also been linked to cervical afferent disturbance. Clinicians must note, however, that smooth-pursuit abnormalities in the neutral neck position or saccadic eye movement may reflect CNS impairment, particularly in some severe cases of persistent pain following neck trauma (17). Furthermore, some medications and psychological conditions can influence eye movement control.

Ambient visual system damage is suspected in cases of demonstrable convergence and accommodation insufficiency and eye alignment malfunction. This may be important because the ambient visual system is integral for spatial orientation. The majority of these studies showing oculomotor deficit have been conducted in concussion patients and conclude that their findings are potentially related to impairments in cortical and subcortical function.

Cervico-ocular reflex (COR) dysfunction has been demonstrated in whiplash and idiopathic neck pain patients, which supports the theory that cervical afferent disturbances are the cause of these deficits.

Some studies have also demonstrated that dizziness and signs of sensorimotor control disturbance may be indicative of poorer prognosis with traumatic neck pain (18). This implies that assessment, differential diagnosis and management of sensorimotor control disturbance may be important, particularly in the context of chronicity prevention. Given this evidence, cervical joint position, movement sense, balance, and oculomotor and coordination disturbances should be routinely investigated in all patients with traumatic neck pain, regardless of symptoms. While some reported symptoms are likely secondary to altered cervical afferent input to the sensorimotor control system, there is potential for other causes in some patients, thus requiring thorough investigation of other possible differential diagnoses.

Clinical Application & Conclusions:

Differential Diagnosis and suggested management of sensorimotor disturbances in those with traumatic neck pain:

Cervicogenic Dizziness (CD) is typically episodic, described by the patient as “unsteadiness” or “light-headedness”, and lasts minutes-to-hours. It additionally should have a close relationship to neck pain and be triggered by specific neck movements or positions. The suggested cause is abnormal cervical afferent input. Relief of neck pain typically relieves symptoms. CD may also be associated with blurred vision and nausea. The primary objective findings are cervical musculoskeletal impairments, JPE < 4.5 degrees, increased sway, balanced neck torsion, positive smooth pursuit neck torsion testing and a positive trunk-head coordination test. Treatment should be targeted to the cervical spine and sensorimotor system. EDITOR’S NOTE: cervicogenic dizziness should be treated as a diagnosis of exclusion, after you have ruled out more severe causes of dizziness.

Symptoms of vertebral artery injury are typically described as episodic fainting and vertiginous dizziness lasting several seconds (patients will often report severe headache and/or neck pain as well). Symptoms are provoked by sustained neck extension and/or rotation and are relieved by bringing the neck back to neutral. Associated symptoms include dysarthria, hemiparesis, dysesthesia, diplopia, dysphagia, drop attacks, nystagmus, nausea, numbness and vertebral insufficiency. VBI tests may be positive (they are generally not considered useful, however), but more likely objective findings include unilateral severe headache and transient neurological disturbances related to VA function. Referral to a neurologist and/or emergency department for further evaluation is absolutely necessary.

Benign Paroxysmal Positional Vertigo (BPPV) is typically described as discrete attacks of vertiginous dizziness lasting seconds (patient normally feels like they are spinning). Symptoms are typically provoked by rolling in bed, looking up or lying down, and subside by staying in the provoking position (that is, the vertigo will habituate when movement stops). BPPV vertigo may also be accompanied by nausea and/or vomiting. The Dix-Hallpike or head roll maneuvers are typically used for confirmation, while the Epley (preferably) and BBQ roll maneuvers can be used for treatment. The suggested cause is endolymph debris.

Perilymph Fistulae (PF) are described as episodic or constant vertigo, disequilibrium and motion intolerance. Symptoms are exacerbated by visual challenges, increased intracranial or atmospheric pressure (i.e. blowing nose) and loud noises, and relieved by rest and activity avoidance. Associated symptoms include unilateral tinnitus, aural pressure and hearing loss. The purported cause is leaking of perilymph fluid into the middle ear. PF is confirmed by positive pressure and Valsalva tests. Referral to ear-nose-throat (ENT) and surgery are indicated.

Peripheral Vestibular (PV) issues are typically described as constant unsteadiness, episodic vertigo, and motion intolerance lasting seconds to minutes. Symptoms are aggravated by head positions or movement, and relieved by keeping the head/body still (BPPV would fit into this category). Associated symptoms include nausea, vomiting, hearing loss, Tinnitus, and ear fullness (the presence of the latter three would shift us from a BPPV differential into Meniere’s or vestibular neuronitis/labyrinthitis). Vestibular rehabilitation, central adaptation habituation, and cervical sensorimotor and MSK rehab are indicated, as well as medical intervention depending on the specific diagnosis.

Central Vestibular (CV) issues are described by disequilibrium and motion intolerance. Relieving factors are uncertain. Associated symptoms include nausea, imbalance and CNS signs from brain stem and cerebellar dysfunction. CV is confirmed by the presence of spontaneous or gaze-evoked nystagmus, oculomotor deficits and ataxia. Suggested treatments include tailored oculomotor, vestibular, balance and gait rehabilitation and/or tailored sensorimotor and cervical MSK interventions.

A psychological etiology of sensorimotor disturbances is described by variable frequency/duration of floating, rocking and fullness in the head. Symptoms are exacerbated by stress, anxiety and hyperventilation, and relieved by relaxation. Associated symptoms include heart palpitations, chest tightness and a ‘lump in the throat’. The suggested causes are secondary to anxiety and stress. Treatments should include meditation, mindfulness, stress management, and tailored sensorimotor and cervical MSK rehabilitation.

Implications for Management:

Management of the abovementioned disturbances is likely to be multimodal. The primary and secondary adaptive changes in the sensorimotor control system must be addressed and tailored to the individual patient. There may be tremendous overlap in conventional management. There is often a need to address the cervical MSK impairments when neck pain is associated with vestibular pathology or generalized dizziness.

Multiple studies have demonstrated improvement in dizziness and/or sensorimotor control in those with traumatic neck pain following manual treatment to the cervical spine. Correction of cervical afferent input is likely the reason for symptomatic improvement (this requires more research, however). Acupuncture has been shown to improve cervical JPS, dizziness and standing balance, while manual therapy has demonstrated improvement in dizziness and JPS. Cervical muscle endurance training has been shown to improve balance in whiplash patients.

Some evidence demonstrates that treatment programs emphasizing gaze stability, eye-head coordination, and/or head-on-trunk relocation have led to improvements not only in sensorimotor impairments but also neck pain and/or perceived disability in patients with traumatic neck pain. Vestibular rehab has been shown to improve symptoms of concussion, and improved dizziness and balance in WAD patients.

Studies including both eye-head coupling and coordination exercises as part of a multimodal approach have demonstrated improvement in neck pain, JPS and postural stability in traumatic neck pain and chronic whiplash. A patient-tailored sensorimotor approach, with exercises aimed to improve identified deficits in cervical joint position, movement sense, oculomotor function, and static and dynamic balance may be the best practice and is clinically recommended. Use of a similar combination of cervical MSK and vestibular interventions with or without vision therapy has been suggested for those with concussion and associated neck trauma. Regardless, this area of investigation is in its infancy and requires more research.

Considerable evidence exists to support the importance of cervical afferent dysfunction in the development of dizziness, unsteadiness, visual disturbances and altered balance. It has also been demonstrated that eye and head movement control is impaired following neck trauma. This variability in etiology and symptomatology implies that a thorough evaluation is required to identify primary and secondary causes, and to implement tailored treatments. Sensorimotor evaluations should be included as a component of routine assessment and management in those with traumatic neck pain, including those with concussion, vestibular system damage and visual pathology/deficits.

Study Methods:

This article was a clinical commentary. As such, no search strategy or statistical analysis were described.

Study Strengths / Weaknesses:

This commentary was incredibly thorough and discussed a variety of biomedical differential diagnoses and their associated findings. However, the paper did not provide thorough “how-to” instructions on best practices for clinically identifying these issues. Also, while comprehensive, the author did not delineate which specific manual therapy or vestibular/sensorimotor rehabilitation strategies are indicated to manage different clinical syndromes (perhaps a lot to ask in one paper, but it would have been nice!). Additionally, they only touched upon the notion of psychological/psychogenic causes of dizziness and sensorimotor dysfunction. It is arguable that identification of such psychological comorbidities that are generally poorly understood by most clinicians could impair recovery. More effort must be made to educate practitioners on the relevance and diagnosis in this area.

Additional References:

  1. Treleaven J. Sensorimotor disturbances in neck disorders affecting postural stability, head and eye movement control. Man Ther 2008; 13: 2-11.
  2. Baloh R & Halmagyi G. Disorders of the Vestibular System. New York, NY: Oxford University Press; 1996.
  3. Solarino B, Coppola F, Di Vella G, et al. Vestibular evoked myogenic poten¬tials (VEMPs) in whiplash injury: a prospective study. Acta Otolaryngol 2009; 129: 976-981.
  4. Treleaven J, Jull G & Sterling M. Dizziness and un¬steadiness following whiplash injury: character¬istic features and relationship with cervical joint position error. J Rehabil Med 2003; 35: 36-43.
  5. Treleaven J & Takasaki H. Characteristics of visual disturbances reported by subjects with neck pain. Man Ther 2014; 19: 203-207.
  6. Revel M, Andre-Deshays C & Minguet M. Cervi¬cocephalic kinesthetic sensibility in patients with cervical pain. Arch Phys Med Rehabil 1991; 72: 288-291.
  7. de Vries J, Ischebeck BK & Voogt LP, et al. Joint position sense error in people with neck pain: a systematic review. Man Ther 2015; 20: 736-744.
  8. Sterling M, Jull G, Vicenzino B et al. Development of motor system dysfunction following whiplash injury. Pain 2003; 103: 65-73.
  9. Kristjansson E, Hardardottir L, Asmundardottir M, et al. A new clinical test for cervi¬cocephalic kinesthetic sensibility: “The Fly”. Arch Phys Med Rehabil 2004; 85: 490-495.
  10. Kristjansson E & Oddsdottir GL. “The Fly”: a new clinical assessment and treatment method for deficits of movement control in the cervi¬cal spine: reliability and validity. Spine 2010; 35: E1298-E1305.
  11. Stapley PJ, Beretta MV, Dalla Toffola E, et al. Neck muscle fatigue and postural control in patients with whiplash injury. Clin Neurophysiol. 2006; 117: 610-622.
  12. Treleaven J, LowChoy N, Darnell R, et al. Comparison of sen¬sorimotor disturbance between subjects with persistent whiplash-associated disorder and subjects with vestibular pathology associated with acoustic neuroma. Arch Phys Med Rehabil 2008; 89: 522-530.
  13. Heikkilä HV & Wenngren BI. Cervicocephalic kinesthetic sensibility, active range of cervical motion, and oculomotor function in patients with whiplash injury. Arch Phys Med Rehabil 1998; 79: 1089-1094.
  14. Mosimann UP, Müri RM, Felblinger J, et al. Saccadic eye movement disturbances in whip¬lash patients with persistent complaints. Brain 2000; 123(4): 828-835.
  15. Treleaven J, Jull G & Lowchoy N. Smooth pur¬suit neck torsion test in whiplash-associated disorders: relationship to self-reports of neck pain and disability, dizziness and anxiety. J Rehabil Med 2005; 37: 219-223.
  16. Wenngren BI, Pettersson K, Löwenhielm G, et al. Eye motility and auditory brainstem response dysfunction after whiplash injury. Acta Otolaryngol 2002; 122: 276-283.
  17. Cobo EP, Mesquida ME, Fanegas EP, et al. What factors have influence on persistence of neck pain after a whiplash? Spine 2010; 35: E338-E343.
  18. Hildingsson C & Toolanen G. Outcome after soft-tissue injury of the cervical spine. A pro¬spective study of 93 car-accident victims. Acta Orthop Scand 1990; 61: 357-359.