Is a Definitive Diagnosis of Cervical Possible in 2020? A Narrative Review and a Proposed Diagnostic Algorithm

Jianli Jan Wu. SAERA. School of Advanced Education Research and Accreditation

INTRODUCTION Basic science, animal and human clinical research worldwide incidence rate in adults of 15–20% has demonstrated evidence for the labyrinth and (Neuhauser, 2016) and prevalence rate of 17-30% cervical afferent influence over somatic motor (Murdin & Schilder, 2015). Common attributed control in human movement. The multi modal causes were cardiovascular and sensory integration required in this system is otological/peripheral with up to 80% of cases complex. Multiple afference inputs allow for classified as “no specific diagnosis possible” redundancy and adaptation. However, failure to (Bösner et al., 2018). Vestibular related vertigo compensate can result in clinically relevant and accounts for 1⁄4 of dizziness complaints, this functional disabilities that have social and increases with age and with a 3:1 female gender economic impact. Dizziness and vertigo are some prevalence (Neuhauser, 2016). of the most common complaints among patients Vestibular related reductions in quality of life presenting to primary care physicians, outcomes are common in addition to substantial neurologists, and otolaryngologists. These economic burdens (Agrawal et al., 2018; Bronstein symptoms are nonspecific vestibular symptoms et al., 2010; Ferrer-Peña et al., 2019; Murdin & (Bisdorff et al., 2009) and include a wide range of Schilder, 2015). Direct (healthcare related) and differential diagnosis. The following paper serves indirect (sick leave and disability) costs have to capture the current state of the literature with recently been estimated at 64,929 USD per patient regard to diagnostic considerations and presents lifetime or a lifetime societal burden of 227 billion an evidence informed clinical algorithm of what USD for the US population over 60 years of age has been historically and clinically known as (Kovacs et al., 2019). This represents a significant cervical vertigo or cervicogenic dizziness. functional and economic burden on the affected Epidemiology patient, their families and on society as a whole. The incidence of dizziness with or without neck In a study of 288 chiropractic practices in Australia, pain has been well documented in the scientific and dizziness was present in 28% of all neck pain medical literature (Ferrer-Peña et al., 2019), with a patients with 24.1% being diagnosed with SAERA – School of Advanced Education, Research and Accreditation cervicogenic vertigo (Vindigni et al., 2019). reproduction and were also observed However, there exists a paucity of quality with neck bending. epidemiological studies on specific vestibular From the outset, there existed multiple competing disorders (Murdin & Schilder, 2015). Dizziness can aetiologies of cervical vertigo: Ryan and Cope as be general manifestations of neurologic, described above with their 3 distinct mechanisms; cardiovascular, psychiatric, or vestibular Maran (1963) discussed aetiologies of arthritis, disorders. However, dizziness and neck pain can vertebral artery occlusion, stenosis of the basilar also be symptoms of other more life-threatening artery and proprioceptive connections, and; Weeks diseases. It can be part of the prodrome of arterial and Travell (1955) and Gray (1956), who reported dissections (Ohshima et al., 2019), tumours or on myofascial pain syndrome and extra- masses (Darouassi et al., 2017), or rotational labyrinthine causes of vertigo and its symptomatic vertebral artery occlusion (Bow Hunters relief with intramuscular injections of anaesthetic. Syndrome) (Zaidi et al., 2014). Nomenclature These global statistics highlight the need and Currently naming conventions of cervical vertigo benefits of prompt diagnosis of vestibular have been debated; proposed clinical aetiologies symptoms. Grill et al. (2018) commented on have expanded beyond spondylosis, and; a paucity inappropriate and insufficient diagnostic accuracy of high-powered diagnostic tests have hampered and treatment timeliness in Europe. He attributes the acceptance of this clinical entity. Cervical this to a lack of interdisciplinary collaboration, vertigo is considered a diagnosis of exclusion due insufficient knowledge of standards in diagnosis to a lack of reliable and valid diagnostic tests and and therapy and a lack of prospective multicentric its incidence in a tertiary audiology clinic was studies. reported at 17% (Somefun et al., 2010). For the Early cases and a historical view of Cervical Vertigo purpose of this essay, cervicogenic; cervical; and Cervical Vertigo as a clinical entity was first neck are all deemed to be equivalent in the described in a series of four cases by Ryan and symptomatic description of vestibular symptoms Cope (1955). In their seminal case study, they had attributed to the cervical region. There exists a isolated instances of Cervical Vertigo from patients paucity of: direct causal evidence for, and; that had 1) cervical spondylosis 2) patients treated diagnostic specificity for this diagnosis. Until such with neck traction and 3) patients that had certain time that one is formalized, the next appropriate types of neck injury. Their clinical characteristics naming convention should rely on specific observed included posterior neck pain or stiffness, symptomatic descriptors. Previously used suboccipital pain and postural vertigo. Symptom definitions of dizziness included: vertigo, disequilibrium, presyncope, or light-headedness. SAERA – School of Advanced Education, Research and Accreditation

This nomenclature is an often semantically driven of distorted self-motion during an otherwise source of much divisiveness in the medical normal head movement; (non-vertiginous) community (Stanton et al., 2007; Lystad et al., dizziness is defined as the sensation of disturbed or 2011). impaired spatial orientation without a false or Cervicogenic Vertigo, in its evolution of distorted sense of motion, and; postural symptoms nomenclature from cervical vertigo or cervical are balance symptoms related to maintenance of proprioceptive vertigo has slowly given way to postural stability, occurring only while upright cervical/cervicogenic dizziness. Recently a new (seated, standing, or walking) contrary to non-hierarchical consensus classification has been symptoms linked to changing body posture with presented by the Bárány Society towards an respect to gravity (e.g., standing up). These latter international classification of vestibular disorders symptoms are referred to as “orthostatic”. (ICVD). This classification includes: symptom On the necessity of the monumental undertaking of definitions that are purely phenomenological an ICVD, the authors note: Having structured without reference to a theory on pathophysiology criteria for diagnosis is obviously mandatory for for a particular disease; definitions that are non- disciplines which rely heavily on symptom-driven overlapping and non-hierarchical but allow one or syndromic diagnosis, such as psychiatry and more symptoms to coexist in a particular patient; headache, where often there is no histopathologic, and consideration was given in the choice of radiographic, physiologic, or other independent terminology to ease of translation to languages diagnostic standard available. However, diagnostic beyond English, given current word usage patterns standards and classification are also crucial in (Bisdorff et al., 2009). This new classification areas of medicine such as and prioritizes the future evidence informed clinical rheumatology, where, although confirmatory tests and research usage of symptom timing, duration, do exist, there is substantial overlap in clinical triggers vs inconsistent subjective descriptors features or biomarkers across syndromes (Bisdorff (Stanton et al., 2007; Caplan, 2007). Accordingly, et al., 2009, p1). vertigo and dizziness, indeed all vestibular This classification scheme is still in its infancy and symptoms, are non-hierarchical and can both be with a diagnostic conundrum that exists in used individually or concurrently as valid vestibular symptoms (vertigo or dizziness) vestibular symptom descriptors (Bisdorff et al., attributed to the cervical region, these steps cannot 2009). come fast enough. A valid and reliable operational Bisdorff et al. (2009) defined the following: definition is vital to further research, clinical (internal) vertigo is the sensation of self-motion knowledge synthesis and knowledge translation. when no self-motion is occurring or the sensation The term Cervicogenic Vestibular Symptoms is SAERA – School of Advanced Education, Research and Accreditation utilised here as an evidenced informed general combine input from: cortical; cerebellar; categorisation. oculomotor and; spinal sources, including cervical Neuroanatomical and physiological basis of . (Figure 1) The central lateral, cervicogenic vestibular symptoms medial and descending (spinal) “The brain integrates information from multiple play a prominent roll integrating cervical spine sensory modalities to generate appropriate motor afferents and coordinating efferents between output and create perceptual experiences of the various ipsi and contralateral vestibular, environment.” (Yakusheva, 2019, p21). oculomotor, cerebellar and cervical spine nuclei Spatial orientation to self and the environment is implicated in control of posture via vestibulospinal necessary for survival. The phylogenetic response tracts, the stabilization of gaze via the medial in vertebrates is a complex sensory neuro longitudinal fasciculus/ventral tegmental tract) integration mechanism involving varied and higher order self-motion and spatial interconnections of afferent and efferent signals orientation perception via ascending to/from the vestibular nuclei complex. Vision, thalamocortical tracts. proprioception and vestibular sensory systems It is important to note that faster moving stimuli is provide information about self and the ideally reliant on vestibular pathways as visual and environment. The integration of this information proprioceptive mechanism are too slow acting via central vestibular neurons encodes for accurate (Vidal, 2015; Highstein & Holstein, 2006; Hamid & effective head, eye, neck and trunk control through Sismanis, 2006; Albernaz et al., 2019). Saglam & vestibulo-mediated reflexes for spatial awareness, Lehnen (2014) also highlighted the importance of perception and coordinated movements. feedforward in addition to feedback mechanisms In addition to the primary vestibular receptors of for stabilising active and passive head movements. the labyrinth, the vestibular nuclei receive and

Figure 1. Multimodal integration within the vestibular nuclei. Adapted from Vidal, 2015. SAERA – School of Advanced Education, Research and Accreditation

Cervical spine contributions to gaze stability: The velocity head motion (visual-vestibulo-ocular vestibulo-ocular reflex reflex). Gaze stability is the process of ensuring a still Additional neuronal inputs (Figure 1) are also image on the retina. Improved information involved in the vestibulo-ocular pathways processing and visual perceptions require the including; complementary inputs from the minimization of image movement across the retina. optokinetic and proprioceptive systems; a The vestibulo-ocular reflex and the cervico-ocular behaviourally gated inhibitory input from the reflex directly involve the cervical spine to act in premotor saccadic pathway during gaze shifts concert to maintain images on the retina during (vestibulo-ocular reflex cancellation), and; active and passive head movements. Another efference copies of the motor command (Vidal, visually mediated eye movement is the optokinetic 2015; Cullen, 2012). reflex that help to fix images on the retina and; Recent findings indicate increased vestibulo- saccades, smooth pursuit, vergence and fixation ocular reflex gain in patients with reported that fix the image on the fovea, the area of highest vestibular symptoms (Zamyslowska-Szmytke et visual acuity (Straka et al., 2005). al., 2019). Nevertheless, Grande-Alonso et al. The vestibulo-ocular reflex (encompassing (2018) to the contrary, reported that clinical rotational vestibulo-ocular reflex, translational testing of the vestibulo-ocular reflex via video head vestibulo-ocular reflex and the ocular counter roll impulse testing was found to be normal in patients reflex) is triggered by high frequency head on neck with reported vestibular symptoms. movements that stimulate the peripheral Cervical spine contributions to gaze stability: The vestibular afferents to produce equal and opposite Cervico-ocular Reflex conjugate eye movements to maintain image The cervico-ocular reflex is triggered by lower stability on the retina (Hamid & Sismanis, 2006; velocity neck on trunk movements that stimulate Vidal, 2015). The peripheral vestibular afferents the cervical spine proprioceptive afferents to are 2 sets of 3 orthogonally placed semi-circular produce equal and opposite conjugate eye canals that are sensitive to angular acceleration movements to maintain image stability on the and 1 pair of organs sensitive to linear retina. Animal studies by Neuhuber et al. (1989) accelerations. This reflex relies on the vestibular and Matsushita et al. (1995) demonstrated afferents which has a latency of 7-15ms vs the confirmed evidence of upper cervical primary visual afferents of 100ms (Albernaz et al., 2019), proprioceptive inputs to the vestibular nuclear but because the labyrinth is only tuned to complex and secondary inputs form the cervical acceleration in head movement the visually nuclei. They hypothesised that these afferents mediated reflex is integral to slow and constant SAERA – School of Advanced Education, Research and Accreditation enabled them to contact a variety of precerebellar, by Rijkaart et al. (2004) and Kasai and Zee (1978). vestibulospinal, and pre-oculomotor neurons. However, though adaptable, the presence of a It is hard to make a case for the impact of cervico- cervico-ocular reflex has proven to be highly ocular responses in typical real-life head-on variable in normal, vestibular deficient, neck/truck movements as it is difficult to ascertain presbyvertigo and traumatic subjects (Norre, the functional relevance of isolated laboratory 1987; Kelders et al. 2003; Schubert et al., 2004; generated cervico-ocular responses. In human Ischebeck et al., 2016). studies, Dorn et al. (2017) investigated if cervical Cervical spine contributions to head in space control: spine afferents would induce cervico-ocular The vestibulo-colic reflex reactions. They cited from Holzl et al. (2009) that The vestibulo-colic reflex refers to the “activation in healthy individuals, cervical spine stimulation of neck muscles induced by labyrinthine via a 3d-trunk-excursion chair would produce a (vestibular) stimulation”. It generally functions to diagnostically relevant upbeat nystagmus. Cervical stabilise the position of the head in space (Keshner, transcutaneous electrical nerve stimulation was 2009). Neurophysiological studies by Forbes et al. additionally used to disrupt sensory afferents (2014) indicated that these reflexive responses are produced confirmatory modulation of cervico- evoked regardless of the requirement of the ocular nystagmus reactions. vestibulum to maintain control of head on trunk Recent studies have reported on increases in during postural tasks. They concluded that, cervico-ocular reflex gain in whiplash trauma to “vestibulo-colic reflex coupling... suggest functions the cervical spine and with age with an associated through its closed-loop influence on head posture negative correlation with vestibulo-ocular to ensure cervical spine stabilization.” responses (Kelders, 2003; Kelders, 2005). Cervico- In fact, this short latency reflexive connection is the ocular reflexes are also increased in subjects with basis for the now over 2 decades use of the cervical nonspecific and traumatic neck pain with no vestibular-evoked myogenic potential relative differences in vestibulo-ocular reflexes neurophysiological test for otolith function. (Ischebeck et al., 2016). And the effects reported, “...are likely to represent Additionally, in labyrinthine deficient subjects, otolith-dependent vestibulo-colic and vestibulo- cervico-ocular gains: are increased (Norre, 1987; ocular reflexes, both linear and torsional.” Huygen et al., 1991); replace the vestibulo-ocular (Rosengren & Colebatch, 2018). reflex (Bronstein & Hood, 1986), and; are Like other reflexes centred around the vestibular reversible after vestibular function improvement nuclei complex, most neurons involved in the (Bronstein et al., 1995). The adaptability of the vestibulo-colic reflex are mono, di and trisynaptic cervico-ocular reflex has been further documented between: the vestibular labyrinth ( and SAERA – School of Advanced Education, Research and Accreditation semi-circular canals); neck muscles (via and functionally sensitive to muscle (stretch) vestibulospinal pathways); the length (Dutia, 1988). (adjusts the gain of the vestibulo-colic reflex), and; Happee et al. (2017), demonstrated cervico-colic somatosensory neck afferents. Responsiveness to involvement in head on trunk stabilization with velocity of head movements and polymyogenic reduction in head rotation and translation at a connections enables multiple degrees of freedom lower frequency. They concluded that the cervico- to reflexively compensate for passive and active colic reflex was responsible for intersegmental head perturbations (Keshner, 2009). stability and to prevent spinal buckling. Keshner Compensatory reticulospinal pathways also exist (2009) also documented on an increased to produce short latency vestibulo-colic contribution from the cervico-colic reflex as a behaviours in the event of vestibulospinal compensatory mechanism to maintain head in compromise (Wilson & Schor, 1999). space stability. Of note is Keshner’s (2009) Cervical spine contributions to head on trunk conclusion: postural control: The cervico-colic reflex “Thus, the does not The cervico-colic reflex is a compensatory appear to be directly implicated in response of the neck muscles that is driven by neck generating the initial head stabilizing proprioceptive inputs during motion of the body to response during functional motion. The role stabilize the head on the body. The upper cervical of the vestibular system may actually be one versus lower cervical spine segments have shown of damping the response to the mechanics of to be particularly associated with a higher level of the system and of monitoring the position of afferent input to the vestibular nuclei. This had the head and trunk in space, secondary to been demonstrated clinically and functionally by feedback from segmental proprioceptors, in Bare in 1926 (Hamid & Sismanis, 2006) and de order to minimize the sustained effects of Jong et al. in 1977. destabilization and maintain orientation in The cervico-colic or neck stretch reflex produces space.” (p. 4223-4224) patterns of neck muscle response similar to Cervico-vestibulo-sympathetic connections vestibulo-colic reflex, however at 10x less strength The past 25 years have seen an emergence of data and both the vestibulo-colic and cervico-colic relating to the existence vestibulo sympathetic reflexes “tune the head response” and diminish the connections in the so called vestibulo sympathetic duration and amplitude of head oscillations (Peng reflex of the cardiovascular system (Shortt and et al., 1999). The vestibulo and cervico-colic Ray, 1997; Kawanokuchi et al., 2001; Carter and (muscular stretch) reflexes are additive in nature Ray, 2008; Yates et al., 2014) and direct SAERA – School of Advanced Education, Research and Accreditation connections between cervical spinal and (including muscle spindle and golgi tendon) sympathetic ganglia (Zuo et al., 2014). influences sympathetic preganglionic neuronal It was reported that the vestibular systems are activity. This activity persisted in animals with connected to the sympathetic system via muscle transected brain stems suggesting an alternative sympathetic activity (muscle pump) to the non vestibular pathway for sympathetic outflow. exclusion of skin sympathetic activity (skin sweat Human clinical investigations have also proposed rate, galvanic response or blood flow). Changes extra vestibular, gravi and proprioceptive control were noted in calf blood flow and calf vascular mechanisms of the vestibulo-sympathetic reflex resistance with no change to mean arterial (Normand et al., 1997) and in patients with pressure. The authors suggest that the vestibular bilateral vestibular loss (Kuldavletova et al., 2019). system may assist the baroreflex against A hypothesized theory of developmental tuning of orthostatic challenges and blood flow regulation in posturo-cardiovascular responses involving neck dynamic exercise and that its responses are age afferent inputs in the first few months of life has dependent (Ray & Monahan, 2002). been proposed. This is in consideration of the Kawanokuchi et al. (2001) demonstrated an presence of the co-occurring neck somato-motor account of muscle sympathetic activity being reflex (tonic neck righting reflex) in human suppressed by the vestibulo-sympathetic reflex neonates (Yates et al., 1999). and more recently, studies on otolith stimulation in Blood supply an upright posture have shown a greater The brain is supplied by the internal carotid and sensitivity of the vestibulo-sympathetic reflex vertebral arteries both of which traverse the (Sauder et al., 2008). There have been observed cervical spine. Anteriorly the internal carotid and demonstrated direct and multi synaptic artery branches into anterior and middle cerebral connections from the vestibular nuclear complex arteries that form the anterior portion of the Circle to the medulla that stimulates the preganglionic of Willis. The posterior cerebral artery sympathetic neurons in animals (Holstein et al., communicates with the middle cerebral artery via 2011, Yates et al., 2014). These connections have the posterior communicating artery forming the shorter latencies and act in a complementary posterior portion of the Circle of Willis. The function to the carotid baroreceptors that are internal carotid artery and its branches supply the sensitive to reductions in blood pressure. orbital structures, tympanic cavity, optic tract, Bolton et al. (1998) investigated the role and lateral geniculate nucleus, hippocampal formation, necessity of the vestibular nuclei in the neural amygdaloid, nucleus, globus pallidus, posterior pathway that mediate the cervical-sympathetic limb and retrolentiform part of the internal capsule response. Their results indicated cervical afferents (Wilkinson, 1992). SAERA – School of Advanced Education, Research and Accreditation

The vertebrobasilar arterial system provides for physiological framework for self-motion both the peripheral and central auditory vestibular perception (Goldberg & Cullen 2011; Cullen 2012). system. The labyrinth is supplied by the Efference copy, as defined by von Holst and labyrinthine artery, a branch of the anterior Mittelstaedt in 1950 for the opto-motor response inferior cerebellar artery (AICA). There is no in flies, is a negative copy of a motor command. It is redundancy to the labyrinthine artery and its identical to the principle of corollary discharge supplied structures are sensitive to minimal defined by Roger Sperry in 1950 while studying the disruptions (Hamid & Sismanis, 2006). Occlusion opto-motor response in fish (Binder et al., 2019). of the anterior inferior cerebellar artery can cause Efference copy and corollary discharge are part of total deafness and loss of vestibular function the Reafference Principle that describes how a however one of its branches, posterior vestibular sensory system can cope with self-induced (i.e., artery has many collaterals and disruptions to its “re-afferent”) sensory input. If the efference copy supply may not lead to total loss of saccular and and re-afferent signal are of equal magnitude, the posterior and lateral canal function. subtraction of the efference copy from the The posterior inferior cerebellar arteries branch reafference will cancel the sensory input signal off the vertebral arteries to supply the inferior (Bridgeman & Stark, 1991). This removes conflict cerebellar hemispheres, the dorsolateral medulla between self-movement perception and external and the inferior aspects of the vestibular nuclear sensory input. complex. The basilar artery is the primary artery of In her paper, Cullen (2012), attempts to answer the the pons (Wilkinson, 1992). question of, “How is the processing of self- motion Stenosis, dissection and occlusion of any arterial information adjusted to meet the needs of specific vessels can lead to loss of function, infarct and tasks?” She presents a scheme (Figure 2) to ultimately cell death in the supplied structures. demonstrate the interaction of reafferent Efference copy/corollary discharge as a functional information, other extra vestibular proprioceptive pathophysiological framework information and direct vestibular afferents In a more global systems view, altered concluding that this sensory integration takes proprioceptive input has been regarded as the place early in processing by comparator foremost mechanism for cervicogenic vestibular mechanisms in the cerebellum to allow for symptoms that is grounded in anatomy and accurate motor output and upstream spatial physiology (Karlberg et al., 1996; Magnusson & perception. Vestibular reafference has also been Malmstrom, 2016; Dieterich & Brandt, 2015). utilized as a pathophysiological framework for Efference copy/corollary discharge has been symptoms associated with vestibular presented as a direct or indirect functional neuro- incongruence (Brandt & Huppert, 2016). SAERA – School of Advanced Education, Research and Accreditation

In light of the profound interconnected elements narrative review attempts to identify key between cervico-vestibular connections and diagnostic tests that rule-in Cervicogenic potential pathophysiological mechanisms, this Vestibular Symptoms.

Figure 2. Neural mechanism for the attenuation of vestibular reafference

HYPOTHESIS AND OBJECTIVES As evidenced in the literature to date, there is interplay between the cervical spine and the substantial functional patient, and economic vestibular system. As of the date of the initial societal impact to vestibular symptoms. In search, it has not been clinically possible to 1950, the scientific community was definitively rule-in the diagnosis of cervical introduced to an alternative source of vertigo and its confirmation has only been vestibular symptoms that arose from the possible after excluding all other potential cervical spine. Since then, anatomical, differential diagnoses. neurobiological, neurophysiological and This research paper seeks to answer the neurophysiological studies have theorised, clinical question, “Is a definitive diagnosis of investigated and confirmed the coordinated SAERA – School of Advanced Education, Research and Accreditation cervical vertigo possible in 2020?”. The the current state of the science on objectives are as follows: Cervicogenic Vestibular Symptoms. An online i. To review the current literature for Medline (Ovid) database (ALL 1946 to diagnosis of Cervicogenic Vestibular January 29, 2020) search was conducted on Symptoms; October 12, 2019 and updated on January 30, ii. To investigate updates in aetiology, patient 2020. The keywords utilised were “cervic*” characteristics, and diagnostic criteria of and including “dizz*” or “vertig”. Wildcards Cervicogenic Vestibular Symptoms; were used to capture all iterations of the key iii. To identify sufficiently powerful diagnostic words. Proximity and Boolean operators were tests to rule-in Cervicogenic Vestibular also utilised. All searches were limited to the Symptoms, English language and peer reviewed iii. In the absence of adequately powered publications. Concussion and whiplash tests, to propose a new evidenced informed associated disorders were excluded from the clinical algorithm, and; search to achieve a great degree of specificity. iv. To establish considerations for future Hand searching for treatment and other non- research investigations. diagnosis related studies were found and excluded. METHODOLOGY The results were exported to Mendeley This is a narrative review of the current reference manager for further review and literature. The primary aim is to review the assessment. diagnosis of Cervicogenic Vertigo: its historical concepts; basic science foundations, Table 1 Inclusion and Exclusion Criteria for and; current theories. This will serve as the Article Selection. foundation for our investigation of the most Inclusion Exclusion promising diagnostic tests, patient characteristics and diagnostic criteria for the English Language Concussion creation of a clinical decision-making Peer-reviewed Whiplash algorithm. publications Search strategy The primary question of this research was “Do Treatment sufficiently powerful diagnostic tests to rule- in Cervicogenic Vestibular Symptoms exist?” Secondarily, this research sought to identify SAERA – School of Advanced Education, Research and Accreditation

Primary search history RESULTS 1. ((cervic* adj3 (dizz* or vertig*)) not Clinical aetiology (whiplash or concussion)).mp. [mp=title, Cervical Spondylosis is a common and abstract, original title, name of substance pervasive finding in the reporting of clinical word, subject heading word, floating sub- aetiologies for cervical vertigo (Takahashi, heading word, keyword heading word, 2018; Zheng et al., 2019; Li et al., 2014; Wang organism supplementary concept word, et al., 2011; Yang et al., 2018; Yang et al., protocol supplementary concept word, rare 2017). disease supplementary concept word, unique In a retrospective study, Takahashi (2018) identifier, synonyms], Results: 250 reviewed over 1000 patient visits in a 15- 2. Limit 1 to English language, Results: 149 month period that had a chief complaint of 3. Hand Screen, Results: 125 dizziness. In these patients, over 90% were 4. Hand Screen to exclude treatment, Results: found to have cervicogenic general dizziness 63 and their mean age was 62. In addition, 91% Data extraction and analysis of those that underwent cervical spine MRI The data was synthesised and aggregated into had comorbid cervical spinal canal stenosis; general themes of: clinical aetiologies; patient 80% was able to recall an abnormal cervical characteristics; diagnostic criteria; and spine load; and, occupational and prolonged diagnostic tests. No further exclusions were cervical spine postures were frequent made based on publication types to ensure a triggers. wide breadth of available data. Additional Zheng et al. (2019) investigated imaging reference and citation searches were differences of patients with cervical conducted for completeness and spondylosis with cervical vertigo. This was a confirmation. Background themes include: retrospective study of a group of 31 patients epidemiology; historical cases; vestibular with concomitant cervical vertigo and nomenclature; and, neuroanatomical and spondylosis (myelopathy, radiculopathy and pathophysiological basis for cervicogenic mixed) that underwent total disc replacement vestibular symptoms. surgery. The surgery resulted in the successful reduction of vertigo with the most reduction seen in cases where a herniated disc was the source of compression. This was followed by a more modest reduction in cases SAERA – School of Advanced Education, Research and Accreditation where an osteophyte was the source of degeneration and pain (Wang et al., 2011; Li compression. It was hypothesized that the et al., 2019). results were due to the stimulation of In an observational study of cervical vertigo sympathetic fibres located within the subjects with and without pain, Morinka posterior longitudinal ligament and a (2009) attributed the significant findings of network of sensory fibres around the increased psychiatric dysfunction, orthostatic degenerated cervical disc. hypotension and brainstem dysfunction to Yang et al. (2017) recently suggested that recurrent and chronic pain influence on the Ruffini corpuscles (a type is implicated in the limbic system. Musculoskeletal disease was pathogenesis of cervicogenic vertigo. In their found as a common comorbidity in cervical study, degenerated cervical discs were noted vertigo with: arthritic deformity of the knee to contain an increase in number and joints; head and neck; and, cervical ingrowth of Ruffini corpuscles. Ruffini spondylosis being the most commonly corpuscles are mechanoreceptors that are observed. thought to be sensitised in the presence of Similarly, experimentally acutely induced inflammatory mediators to contribute to cervical pain led to impaired sensorimotor aberrant proprioceptive signals. These control during and after the pain had waned. findings were associated with the incidence of This was also accompanied by dizziness vertigo in the patients with cervical (Malmstrom et al., 2013). spondylosis along with the comorbid Specific to the anatomy of the cervical spine: presence of free nerve endings (pain). In a vascular insufficiency related to the patency follow-up clinical study, Yang et al. (2018), through the paired vertebral and carotid confirmed their histopathological findings in arteries, and; sympathetic deregulation of a group of patients that showed marked cardiovascular control involving the cervico- dizziness and pain relief with surgery vestibular-sympathetic reflexes are (anterior cervical discectomy and fusion) in additional potentially contributing comparison to conservative care controls. mechanisms to vestibular symptoms. The human posterior longitudinal ligament Since 1950, there now exists a proposed has been found to contain sympathetic post organisational framework that provides an ganglionic nerve fibres (Li et al., 2014). Recent explanation of how extra vestibular sensory studies provide support to the hypothesis that (muscle spindle afferents from the eye or irritation to sympathetic nerves contribute to cervical spine) information and direct symptoms of vertigo in patients with cervical vestibular afferents can interact to allow for SAERA – School of Advanced Education, Research and Accreditation adaptation in the event of an efference copy expectation of a gradual onset of vestibular and internal model mismatch (no cancellation symptoms aggravated by neck pain and signal). This theory has subsequently been movements rather than head movements. implicated as a basis for the proprioceptive Wrisley et al. (2000) also reported that the theory of cervical vertigo (Brandt & Huppert, symptoms of cervicogenic dizziness were 2016) in the generation of cervicogenic associated with injury or other cervical spine vestibular symptoms. Cullen (2012) has also disease but their onset may be immediate or implicated this model as an explanation of gradual from days to years following injury. motor learning and plasticity. These symptoms are typically episodic lasting Symptoms and patient characteristics from minutes to hours and are increased with A systematic review conducted by Knapstad neck movements or neck pain and decreased et al., (2019) consolidates the clinical with treatments that relieve neck pain. Table characteristics of patients with cervicogenic 2 lists other clinical characteristics that have dizziness despite methodological variability identified. of the included studies. They reported an

Table 2 Studies that have identified clinical features of cervicogenic vestibular symptoms.

Study Title Author Clinical Features

Cervical vertigo; Brandt & Bronstein, Most common symptom 2001; descriptors of Evaluation of paraclinical tests in the diagnosis of L'Heureux-Lebeau et al., “drunkenness” or “light- cervicogenic dizziness 2014 headedness’”

Chronic neck pain and vertigo: Is a true balance Yahia et al., 2009; Concurrent headache disorder present?

Manual therapy with and without vestibular Lytsad et al., 2011; rehabilitation for cervicogenic dizziness: A systematic review;

Cervicogenic dizziness: A review of diagnosis and Wrisley et al., 2000 treatment

Cervical vertigo; Brandt & Bronstein, Cervical trauma and 2001; spasm Evaluation of paraclinical tests in the diagnosis of L'Heureux-Lebeau et al., cervicogenic dizziness 2014 SAERA – School of Advanced Education, Research and Accreditation

Utility of a brief assessment tool developed from Reid et al., 2017 Cervical Stiffness the Dizziness Handicap Inventory to screen for Cervicogenic dizziness: A case control study

Cervicogenic dizziness - musculoskeletal findings Malmstrom et al., 2007 Cervical spine and muscle before and after treatment and long-term outcome tenderness and tightness

Cervical vertigo; Brandt & Bronstein, Limited cervical spine 2001; range of motion Chronic neck pain and vertigo: Is a true balance Yahia et al., 2009; disorder present?

Diagnostic route of cervicogenic dizziness: Micarelli et al., 2019 usefulness of posturography, objective and subjective testing implementation and their correlation

Chronic neck pain and vertigo: Is a true balance Yahia et al., 2009 Symptoms of impaired disorder present? balance

Cervical vertigo; Brant & Bronstein, 1991; Pain on palpation to upper cervical spine Cervicogenic dizziness - musculoskeletal findings Malmstrom et al., 2007; before and after treatment and long-term outcome;

Evaluation of paraclinical tests in the diagnosis of L'Heureux-Lebeau et al., cervicogenic dizziness 2014

Diagnostic screening Thompson-Harvey and Hain, (2019) created a The Dizziness Handicap Inventory (DHI) is a 41-question survey based on questions from 25-question self-reported questionnaire the Dizziness Handicap Inventory and the utilised to quantify the impact of dizziness on Neck disability Index. They found that these physical, emotional and functional aspects of questions failed to show differences between daily life. Reid et al. (2017) conducted a case- patients with cervical vertigo from vestibular controlled study of cervicogenic dizziness and or patients. They concluded that, general dizziness patients. Using the DHI, they there is substantial overlap in the symptoms attempted to distinguish the 2 dizziness reported by subjects with cervical vertigo and populations and report on the 3 questions those with other vestibular disease or that had the most discriminative ability. A migraine. score of 9 or more on these 3 questions accurately classified the cervicogenic SAERA – School of Advanced Education, Research and Accreditation dizziness group. These questions are: does in any 1 position; the dynamic balance looking up increase your problem; do quick evaluation revealed no differences between movements of your head increase your groups; the sensitivity and specificity for the problem, and; because of your problem, are Cervical Torsion Test was higher than the you afraid to leave your home without having Smooth Pursuit Neck Torsion Test protocol. In someone with you. The authors do note some terms of test discrimination between the overlap of 2 questions with a previous study Cervicogenic Dizziness and Benign on the DHI to identify patients with Benign Paroxysmal Positional Vertigo groups, higher Paroxysmal Positional Vertigo. discriminating ability was found with a Diagnostic tests combination of the Cervical Relocation Test Clinical physical examinations and para- and the Cervical Torsion Test. L’Heureux- clinical diagnostic tests are performed to Lebeau et al’s protocol regarding these two improve diagnostic uncertainty regarding significant tests are as follows: reported symptomology captured during the 1. The Cervical Relocation Test: The Clinical History and Interview and to rule in or subject is seated in a darkened room with a out various differential diagnoses. laser pointer attached to the top of their head. L’Heureux-Lebeau et al. (2014) investigated With their eyes closed the subject is asked to the diagnostic value of: bring their head to and from any cervical Videonystagmography in various cervical spine position back to centre. The variation movements (Smooth Pursuit Neck Torsion (joint position error) in degrees to the centre Test and Cervical Torsion Test); the Cervical point is recorded. L'Heureux-Lebeau et al. Relocation Test; and, a dynamic balance (2014) report a joint position error of 4.5 evaluation (timed 10 metre walk with head degrees as diagnostic. turns). They compared the performance of 2. The Cervical Torsion Test: The subject these tests between a Cervicogenic Dizziness is seated with ocular fixation removed and group (clinical diagnosed via exclusion of eye movements measured. The head is fixed differential diagnosis, associated dizziness by the examiner and the body is turned to with neck pain and cervical spine various degrees of rotation: 90 degrees pain/trauma/disease) and Benign (L’Heureux-Lebeau et al., 2014); 45-90 Paroxysmal Positional Vertigo group. They degrees (Treleaven et al., 2019). The positions arrived at these conclusions: The Cervical are held for a time as eye movements Relocation Test was more specific and (nystagmus) are recorded. L’Heureux-Lebeau sensitive when a 4.5-degree error was made SAERA – School of Advanced Education, Research and Accreditation et al. (2014) report a more than 2 degrees per rotate their body on a swivel chair. Symptoms second nystagmus as diagnostic. provocation in this manner is thought to be Other tests being investigated for the attributed to the cervical spine. A rotation en diagnosis of Cervicogenic Vestibular bloc manoeuvre that is thought to stimulate Symptoms are posturography and its variants the vestibular receptors in isolation has (Karlberg et al., 1996; Wrisley et al., 2000; recently been reported (Reiley et al., 2017). Micarelli et al., 2019) and the Head-Neck Normative data for clinical tests are essential Differentiation Test (Treleaven et al., 2019). to establish quantitative criteria to ensure 1. Static and dynamic posturography accurate diagnosis. Based on the emergence studies typically involve a force platform of evidence for the utility of para-clinical tests where sway and centre of pressure is especially in combination (L'Heureux-Lebeau recorded in eyes open or closed conditions. et al., 2014) and the lack of resource The more comprehensive sensory availability for advanced testing in a clinical organization test involves static environment, Treleaven et al., (2019) posturography in a virtual field with the attempted to identify normative qualitative addition of 4 more dynamic conditions: eyes responses of the Cervical Torsion Test and the opened on sway referenced visual surround; Head-Neck Differentiation Test. eyes open and closed on a sway referenced Treleaven et al., (2019), reports 35(23%) support surface and eyes open on a sway participants experienced symptoms in referenced support surface and surround. response to 1 or more of the 6 test conditions. Scoring and analysis can identify ankle or hip Most of these tested experienced their contributions to balance and the relative symptoms during the Head-Neck impairments of the vestibular, proprioceptive Differentiation Test. The specificity for or visual systems in balance. torsion component in the Cervical Torsion 2. The Head-Neck Differentiation Test is Test was 98.64% and a combined specificity a clinical test that attempts to separate the for both tests was 100%. This represented the vestibular and cervical spine contributions to ability of the tests to successfully rule out the patient’s subjective symptoms. The Cervicogenic Dizziness because those who patient is asked to rotate just their head and experienced symptoms identified qualitative their symptoms are recorded. If symptoms descriptors unlike those of Cervicogenic are provoked by this manoeuvre, it is thought Dizziness patients. They conclude that further to come from vestibular sources. Second, with studies are warranted to investigate the patient's head stabilised, they are asked to subjective symptoms in the target SAERA – School of Advanced Education, Research and Accreditation

(Cervicogenic Dizziness) population was not considered essential for the (Treleaven et al., 2019). diagnosis…” (p10). Diagnostic criteria As the current clinical consensus is to treat In their 2019 systematic review, Knapstad et Cervicogenic Vestibular Symptoms as a al. concluded that the diagnostic criterion of diagnosis of exclusion, the diagnostic Cervicogenic Dizziness was, “based on the inclusion criteria reported in the available patient simultaneously reporting neck pain studies are highly variable and dependant on and dizziness as well as the exclusion of other the study authors. Table 3 outlines some neurological or neuro-otological disorders. utilised diagnostic criteria and their study The distinction between vertigo and dizziness authors.

Table 3. Commonly used diagnostic criteria in the study of cervicogenic vestibular symptoms

Study Title Source Criteria

Clinical characteristics in patients with cervicogenic Knapstad et al., 2019; Vestibular symptoms dizziness: A systematic review; correlated with neck Cervicogenic dizziness: A review of diagnosis and Wrisley et al., 2000 pain treatment

Evaluation of paraclinical tests in the diagnosis of L'Heureux‐Lebeau et al., Temporal association cervicogenic dizziness 2014 to trauma

Cervicogenic dizziness: A review of diagnosis and Wrisley et al., 2000; An ex juvantibus treatment; confirmation of the diagnosis The conundrum of cervicogenic dizziness Magnusson & Malmstrom 2016

Cervical vertigo--reality or fiction? Brandt, 1996; Exclusion of other vestibular and The conundrum of cervicogenic dizziness; Magnusson & Malmstrom, competing disorders 2016; Cervicogenic dizziness: A review of diagnosis and Wrisley et al., 2000; treatment; Yahia et al., 2009;

Chronic neck pain and vertigo: Is a true balance L'Heureux‐Lebeau et al., disorder present? 2014;

Evaluation of paraclinical tests in the diagnosis of Reid et al., 2017; cervicogenic dizziness;

SAERA – School of Advanced Education, Research and Accreditation

Utility of a brief assessment tool developed from the Dizziness Handicap Inventory to screen for Grande-Alonso et al., 2018 Cervicogenic dizziness: A case control study;

Biobehavioural analysis of the vestibular system and posture control in patients with cervicogenic dizziness. A cross-sectional study

DISCUSSION

Diagnosing a non-specific entity overall outcome. This is arguably the most The process of arriving at a defined medical important clinical process involved in the diagnosis is an iterative one. The process is management of health conditions, and is the ideally subject to multiple rounds of weakest aspect of validating Cervicogenic refinement towards minimizing diagnostic Vestibular Symptoms. Essential elements that uncertainty and maximizing certainty. factor into the diagnostic process include a Multiple clinical diagnoses (Differential valid aetiology that has evidential support of Diagnoses) are not unheard of and even the basic and clinical sciences, identifiable less precise ‘Clinical Impression’ is commonly symptoms and patient characteristics, used in the diagnostic process. adequately powered diagnostic tests and Towards improving diagnosis in health care, quantifiable criteria that must be met for the Committee on Diagnostic Error in Health inclusion. Care (n.d.) concluded that “the diagnostic Aetiology process is a complex, patient-centred, There is convincing anatomical, physiological collaborative activity that involves and clinical support for labyrinth and cervical information gathering and clinical reasoning afferent contribution to somato-motor with the goal of determining a patient's health control, human spatial perception, movement problem. This process occurs over time, and locomotion. Of late, there has been a within the context of a larger health care work relative abundance of scientific investigations system that influences the diagnostic process. in the subset of spondylotic patients that (para. 3)” present with vestibular symptoms: a Ultimately the accuracy of this clinical proprioceptive network of: diagnostic process improves patient mechanoreceptors in degenerated discs expectation, therapeutic intervention and (Yang et al, 2017; Yang et al, 2018); SAERA – School of Advanced Education, Research and Accreditation

sympathetic post ganglionic fibres in the The APA Dictionary of Psychology (Retrieved posterior longitudinal ligaments (Li et al, January 21, 2020) defines preafference as: a 2014); and, muscle spindles in deep cervical central brain process in which the muscles (Cullen, 2012) link the clinical somatosensory area is primed to expect the symptoms of pain and cervicogenic vestibular particular sensory inputs that are predicted symptoms in the cervical spondylosis as the consequence of an intended motor population. This potentially establishes action. The concept of preafference applied to another line of evidence that the Cervicogenic cervicogenic vestibular symptoms is a novel Vestibular patient may just be a subset of explanation of how inappropriate those with degenerative changes that affect sensorimotor learning may occur in the the biomechanics and morphology of the presence of dysfunctional and cervical spine structures. inappropriately learned patterns of Additionally, there exists a theoretical basis movement. It can be suggested that for the functional role of several cervical previously learned movements based on structures in the generation of vestibular sensory afferents serve as a foundation for symptoms in the global population. In improved speed of movement generation, general: disruptions, injury and other timing, sequencing and output. This process pathology of the associated blood supply, of motor learning has a role in acquiring new neurological pathways, receptors or movement skills, refining already acquired processing centres can cause vertigo, ones and more importantly may be essential dizziness, unsteadiness and other vestibular in the generation of the internal model. symptoms (de Jong et al., 1977; Albernaz et al., As somatosensation fluctuates as a result of 2019) Proprioceptive, pain, vascular, continued cervical spine degeneration, sympathetically mediated, central vestibular, trauma or pain, pre-efference will always carotid body dysfunction, spondylosis and result in an ever-changing internal model. It arthropathies have previously been can be supposed that the somatosensory area suggested as potential explanatory will never be able to predict relatively quick mechanisms of cervicogenic vestibular changes in the expected sensory inputs. This symptoms. However, fracture, ligamentous presents until now, an unmentioned concept instability, vestibular, visually mediated and of how sensory mismatches between the other differential aetiologies must also be predicted consequence of dysfunctional neck considered as competing diagnosis that also movements in the somatosensory areas for result in vestibular symptoms. self-motion and spatial orientation SAERA – School of Advanced Education, Research and Accreditation

perception can lead to a self-sustaining 1954 and Gordon in 1954 to experimentally pattern of chronic vestibular isolate the components of postural induced symptomatology. These concepts of pre- cervical vertigo. In contrast, Brandt and efference, efference copy and internal model Bronstein (2001) eloquently reasoned that helps to unify the multifactorial aetiology “The perception of head rotation is mediated associated with the complex clinical diagnosis by vestibular, proprioceptive, or visual of cervicogenic vestibular symptoms. receptors. Vertigo should therefore be Patient symptoms and characteristics induced by stimulation of any of these Efforts to quantify key patient characteristics systems.” And that it is “virtually impossible” in higher quality studies have been hampered to have a selective postural test for neck by variability in diagnostic criteria and poor function. methodology (Knapstad et al, 2019; A recent case-controlled study (L’Heureux- Treleaven et al, 2019). However there have Lebeau et al, 2014) was identified that been recent advancements in the ability to attempted to quantify para-clinical tests in the screen potential cases (Thomson-Harvey & diagnosis of cervicogenic dizziness. Para- Hain, 2019; Reid et al, 2017). In the absence of clinical tests are categorised so because they viable clinical diagnostic tests, the require specialised equipment that may not identification of key clinical characteristics be feasible in a strict primary care or via subjective interviews or questionnaires rehabilitation clinical setting due to technical are necessary for screening patients for or logistical considerations. No other higher further paraclinical diagnostic testing. quality studies of clinical or paraclinical Diagnostic tests diagnostic tests were identified in this research review. In consideration that is a near impossibility to There is currently no established reliable isolate neck and head movements in real clinical test for the entity of cervicogenic world conditions, Ryan and Cope (1959), vestibular symptoms and in addition there makes historical mention of: De Kleijn’s are often better-established clinical diagnoses plaster cast; Tait and McNally’s tilt table and; to explain these symptoms. The diagnostic Nylen’s posture table as experimental process attempts to identify key patient attempts to isolate cervical spine motion. characteristics of a condition in order to rule Ryan and Cope (1959) themselves utilized a a particular diagnosis in or out. At present, the “collar test” involving a plaster collar and a entity of cervicogenic vestibular symptoms modified version of the protocols established cannot be diagnostically ruled in (Treleaven by Dix and Hallpike in 1952, Cawthorne in SAERA – School of Advanced Education, Research and Accreditation

et al, 2019; Yacovino & Hain, 2013). This more serious differential diagnosis and places inability to rule cervicogenic vestibular more importance on the diagnostic process as symptoms in as a diagnosis subsequently a whole. A non-exhaustive list of differential requires one to rule out all competing diagnoses to rule out before ruling in diagnosis and thus making cervicogenic Cervicogenic Vestibular Symptoms appears in vestibular symptoms a diagnosis of exclusion. Table 4. A diagnosis of exclusion demands a higher level of clinical diagnostic fortitude to rule out

Table 4. Differential diagnosis for Cervicogenic Vestibular Symptoms.

Cervical spine fracture/ligamentous instability

Cerebrovascular disorder ● infarct ● haemorrhage ● dissection ● occlusion ● /transient ischemic attack

Neurological ● cord compression syndromes ● cerebral herniation

Central vestibular disease ● tumour/mass effect ● ● hereditary ataxia ● vestibular migraine ● cerebellar atrophy ● axon damage (concussion)

Peripheral vestibular disease ● benign paroxysmal positional vertigo ● Meniere’s disease ● ● neuronitis ● infection ● tumour/mass effect ● persistent postural-perceptual dizziness ● otosclerosis ● bone dysplasia ● labyrinth concussion SAERA – School of Advanced Education, Research and Accreditation

Ototoxicity/alcohol/nutrient deficiency

Orthostatic hypotension

Autoimmune, metabolic, endocrine disease

Functional and psychiatric vestibulopathy

Adapted from Chan, 2009; Wrisley et al., 2000; Albernaz et al., 2019; Reiley 2017, and; Girasoli et al., 2018.

While advances have been made in the field by pathology, and; (3) the elimination of other combining existing diagnostic tests to causes of dizziness. improve overall test power, the apparent lack of As noted previously, there exists in studies a consistency in laboratory and clinical cervico- great variety with respect to their diagnostic vestibular-ocular data and patient presentations criteria. This methodological variability will only reviewed in this research report implies an improve with common definition, nomenclature inherent adaptability in the cervico-vestibular and a method of specific diagnosis. In the absence system. This may serve to explain the of any sufficiently powerful diagnostic tests, we unreliability of subjective symptom reporting, must be reliant on diagnosis ex juvantibus patient characteristics and the resulting (Magnusson & Malmstrom, 2016). This is variability in diagnostic test results. considered a top-down approach where temporal Diagnostic criteria association of dizziness and neck pain and the Higher quality sensitive and specific diagnostic amelioration of dizziness or other vestibular tests that allow for the diagnosis of cervicogenic symptoms is observed with treatment of the vestibular symptoms have been “elusive” and associated cervical spine dysfunction. increase the challenge of diagnosis. In order to Reliable and valid diagnostic tests are vital in the guide clinical diagnosis and research, the establishment of diagnostic criteria. diagnosis of cervicogenic dizziness is suggested Paradoxically, in order to adequately validate by the utilising criteria. Wrisley (2000) proposed diagnostic tests and further scientific inquiry, the following criteria: (1) a close temporal reliable and valid diagnostic criteria is also vital relationship between neck pain and symptoms of to methodologically sound studies. dizziness, including time of onset and occurrence of episodes; (2) a previous neck injury or SAERA – School of Advanced Education, Research and Accreditation

Proposing a new diagnostic algorithm Due to the lack of evidence for sufficiently I propose the following algorithm based on the powerful diagnostic tests (Knapstad et al, 2019); most recent evidence. This new clinical algorithm no systematic review has been successfully allows for a logical progression through the 3 attempted regarding the diagnosis of this clinical most common patient clinical characteristics and entity. In its place several authors have suggested the upholding of the medical principle of clinical decision-making algorithms to best guide “primum non nocere” by ruling out immediate the clinical diagnosis of this condition (Wrisley et life-threatening diagnosis. al, 2000; Reiley et al 2017).

Chief complaint of vestibular Neck pain and neck movements associated with History of temporaly associated neck pain or symptoms vestibular symtoms pathology

Rule out RED flags

concurrent headache YES, vestibular NO, cericogenic disorder and/or dizziness unlikely cervicogenic dizziness likely Rule out migraine or other Rule out all other primary/secondary Rule out other potential differential headache vestibular and other diagnosis differential NO, rule out other diagnoses vestibular disorder and/or cervicogenic dizziness Modified DHI>9

Cervical relocation test (4.5 degrees or greater) and Dix-Halpike cervical torsion test (nystagmus >2 degrees/sec) with or without positive head/neck differentation test Positive test

NO, rule out other YES to at least 1 of: describes symtoms as NO or no reported symptoms with head vestibular disorder and/or "drunkenness" or "lightheadedness"; decreased C- neck differentation test and torsion cervicogenic dizziness spine ROM; pain on C-spin palpation; confirmed component of cervical torsion test. cervical spine degenerative joint or disc disease Cervicogenic dizziness unlikely.

YES, Posterior canal Reevaluate differential BPPV Cervicogenic Trial of care to diagnoses vestibular symptoms confirm diagnosis highly likely

Figure 3: Proposed clinical algorithm for cervicogenic vestibular symptoms. SAERA – School of Advanced Education, Research and Accreditation

In addition: the inclusion of newer screening consistency and add statistical power. Third, tools that have shown potential to research in promising clinical and paraclinical discriminate between competing diagnosis tests (Cervical Neck Torsion, Head-Neck (BPPV or Cervicogenic Vestibular Symptoms); Differential Test, Cervical Repositioning and combining Cervical Relocation and Torsion posturography) also needs consistency in its Tests to improve diagnostic power, and; methodologies to establish clinical validity. identifying specific patient symptom This may also serve as a method to establish descriptors and comorbidities differentiates and measure the adaptive capacity of the this from previously published algorithms. It cervical spine in relation to the onset of will undoubtedly require further verification vestibular symptoms. Fourth, new evidence and validation. suggests that it is reasonable to attribute cervical spondylosis as a primary factor or To date, this is the only clinical algorithm to patient characteristic in the incidence of take into account the most recent scientific cervicogenic vestibular symptoms. The discoveries. I expect that this will improve the necessary level of degenerative change to discrimination and identification of patients evoke vestibular symptoms and a way to that present with Cervicogenic Vestibular objectively measure these levels in the Symptoms. Ultimately, the overall utility of general cervicogenic vestibular population is the presented algorithm will be subject to yet to be established. validity and reliability of the new inclusions. Retrospective analysis of this algorithm on a CONCLUSION large enough cohort of “confirmed” cases of A newly proposed etiological framework Cervicogenic Vestibular Symptoms would based on pre-afference and efference copy serve to add further validation. should help to organize and drive future basic Future research considerations science and top-down clinical research, Future studies must prioritize the following although questions still remain regarding the considerations. First, inconsistencies should potentially etiologic but often coincidental be reduced with regard to patient findings of vestibular symptoms and neck characteristics for improved internal validity dysfunction or headache. Indeed, a bottom-up and the ability to pool subjects in systematic approach highlights fallacy in building an reviews. Second, a common diagnostic etiologic mechanism on the supposed cervico- criterion is considered high priority for future ocular responses. The balance of evidence research to improve methodological suggests that diagnosis of vestibular SAERA – School of Advanced Education, Research and Accreditation

symptoms attributed to the cervical spine 3. Albernaz, P. L. M., Zuma e Maia, F., Carmona, S., Cal, R. V. R., & Zalazar, G. (2019). The New cannot be definitively made. As such, the Neurotology. Springer International covenant between patient and physician Publishing. https://doi.org/10.1007/978-3- dictates implicitly, that priority is placed on 030-11283-7 4. Bisdorff, A., Von Brevern, M., Lempert, T., the health and safety of the patient. In the case Newman-Toker, D. E., Bertholon, P., Bronstein, of a patient presenting with vestibular A., Kingma, H., Antonio Lopez Escamez, J., Magnusson, M., Minor, L. B., As Pérez, N., symptoms and distinct or associated neck Perrin, P., Suzuki, M., Waterston, J., & Yagi, T. dysfunction, any course of care should rule (2009). Classification of 5. vestibular symptoms: Towards an out the causes with life threatening and international classification of vestibular severe consequences. A course of care for the disorders. Journal of Vestibular Research, 19, relatively minor cervical spine dysfunction 1–13. https://doi.org/10.3233/VES-2009- 0343 and associated vestibular symptoms can then 6. Bolton, P. S., Kerman, I. A., Woodring, S. F., & be implemented. Ultimately, while the Yates, B. J. (1998). Influences of neck afferents on sympathetic and respiratory nerve activity. etiological basis of this diagnosis is important, Brain Research Bulletin, 47(5), 413–419. the reality of its clinical diagnostic relevance https://doi.org/10.1016/S0361- 9230(98)00094-X is likely inconsequential as the management 7. Bösner, S., Schwarm, S., Grevenrath, P., of neck dysfunction (pain, proprioceptive or Schmidt, L., Hörner, K., Beidatsch, D., Bergmann, M., Viniol, A., Becker, A., & otherwise) with or without associated Haasenritter, J. (2018). Prevalence, aetiologies vestibular symptoms is equivalent in either and prognosis of the symptom dizziness in case. Cervicogenic vestibular symptoms primary care – a systematic review. BMC Family Practice, 19(1), 33. remain a diagnosis of exclusion as we await https://doi.org/10.1186/s12875-017-0695- scientific and clinical studies performed with 0 8. Brandt, T. (1996). Cervical vertigo--reality or sufficiently higher levels of rigor. fiction? Audiology & Neuro-Otology, 1(4), 187– 196. 9. Brandt, T., & Bronstein, A. M. (2001). Cervical

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