Prevalence of cervical dysfunction in those referred for treatment of vertigo or dizziness

1 Introduction

The cervical spine is often an under recognized cause of patients’ symptoms of dizziness and vertigo. Many clinicians utilize a battery of tests to assess for the presence of cervicogenic dizziness/vertigo [1] The lack of a definitive singular test to determine if the cervical spine is responsible for the patients symptoms combined with how it was first described in the literature has led many authors to conclude falsely that cervicogenic dizziness and cervicogenic vertigo are diagnoses of exclusion [2].

Making the diagnosis of cervicogenic dizziness or cervicogenic vertigo is further complicated by the issue of pain. Early literature exploring cervicogenic dizziness/vertigo stated that pain must be present in the neck or occipital region in order to make the diagnosis of cervicogenic dizziness or cervicogenic vertigo [3, 4]. These previously published studies would therefore recommend clinicians rule out the possibility of someone’s symptoms be attributable to their cervical spine if the patient did not report pain in the neck or suboccipital region. Clinicians armed with these recommendations often do not assess the cervical spine for involvement in those patients who were reporting symptoms of dizziness/vertigo but did not report pain. These clinicians would therefore conduct their evaluation and treatment based around well-established protocols which focused on addressing the vestibular system as well as brain processing in the early phases of rehabilitation in the hopes of addressing the patients’ chief complaints as quickly as possible. As these treatments failed or recovery was delayed the clinician may begin to suspect cervical involvement and then screen the neck appropriately. Unfortunately, if the cervical spine is not assessed during the initial evaluation due to no reports of pain in the region, accurate assessment of the cause of the patient’s complaints will be missed and those patients who do exhibit cervical involvement will ultimately experience delays in the assessment and treatment of any cervical pathology. This would lead to poor patient outcomes and increased medical expenses.

Recently published studies have evaluated the prevalence of cervical pain or musculoskeletal pain in patients complaining of dizziness or vertigo [2, 5]. Many of these newer studies argue that pain in the cervical spine or occipital region is not necessary for the cervical spine to be the cause of the patient’s symptoms of dizziness/vertigo and even concussion [4, 6–8]. This is based on the afferent neural connection between the muscles, intervertebral discs, facet joints and connective tissues (muscle, tendon and ligaments) of the neck region to the brain [9]. These afferent nerve fibers provide important information to the brain in regards to where the neck and head is in relation to the organs within the inner ear and eyes [9]. He et al. [9] presented an excellent synopsis of this afferent input from the various sensory organs located in the cervical spine and their direct input into the vestibulospinal nucleus. They and other authors have found that the sensory organs located in the cervical region, including the facet joints, cervical discs and extensor and deep rotator muscles located in the occipital region extending down to the fifth cervical vertebra can directly cause patients to experience the symptoms of dizziness/vertigo [4, 6, 7, 9]. It can therefore be concluded that any pathology or musculoskeletal condition, which creates abhorrent afferent nerve signaling from these structures, has the ability to impact the patient’s sense of balance leading to the subjective complaints of dizziness/vertigo without necessarily causing pain. This supposition is supported by the fact that interventions designed to improve mobility in the cervical region or create a reduction afferent nerve firing from the structured located in the cervical region has the ability to reduce these symptoms. Traditional manual therapy interventions such as massage [10], mobilizations [11–14] and manipulations [15, 16] when applied to the cervical spine have been shown to be effective at reducing or eliminating the symptoms of dizziness and vertigo [11–13, 17]. These improvements are most likely due to the manual interventions directly influencing joint, muscle and connective tissue mobility [12, 16], which then modulates or reduces adherent afferent input into the vestibulospinal nucleus. These manual techniques are less invasive as compared to electrical ablation which has also been shown to also be effective in alleviating symptoms of cervicogenic dizziness [9].

Having demonstrated that mobility restrictions within the upper cervical spine are often found in patients referred to physical therapy with subjective complaints of dizziness, vertigo and concussion in another paper [7], the authors hoped to quantify the prevalence of cervical spine dysfunction in a larger prospective study. In their first paper the authors only assessed the Atlanto-axial joint. Given He et al’s [9] findings, we expanded our assessment of cervical mobility from the first through fifth cervical vertebra in those referred to physical therapy for treatment of dizziness, vertigo, BPPV and concussion.

2 Methods

This study was approved by the Johnson & Wales University IRB #210401. All subjects read and signed the informed consent form prior to being enrolled in the study. Patients (n = 100) referred to physical therapy center with a diagnosis of dizziness, vertigo, BPPV or concussion were asked to participate in the research study. Eighteen refused or did not match the inclusion criteria for the study, leaving 82 patients to be included in the study. After reading and signing the appropriate consent documentation the authors examined all 82. Testing included direct assessment of Atlanto-axial mobility via the seated cervical flexion rotation test [SeatFRT] [7] and the supine cervical flexion rotation test [SupFRT] [18]. Joint mobility assessments were then performed starting C2-C3 joints extending downward to the level of C4-C5 vertebra. At the conclusion of the research phase of the physical therapy evaluation the results of this manual assessment were combined with other findings from the evaluation and where the shared with the patient. The authors then shared the results of their findings with the patients’ referring provider so that the appropriate information was being relayed to all concerned parties. A physical therapy treatment program then commenced as deemed appropriate by the evaluating clinician and agreed upon by the patient. No subjects dropped out of the study after signing the consent documentation and there were no unexpected or adverse reactions.

3 Results

Eighty-two subjects took part in the study 58 female (70.7%) and 24 male (29.3%) with a mean age of 54.3±16.4 years took part in this study. Their average height was 64.8±3.9 inches and their weight 179.4±40 lbs. SupFRT was positive for upper cervical involvement in 73.2% of the subjects. The SeatFRT was found to be positive for upper cervical involvement in 74.4% of subjects. Cervical spine posterior to anterior mobility testing from the junction of C2-C3 to C4-C5 noted restrictions in joint mobility in 59 (72%) of subjects. It should be noted that mobility restrictions were noted at 2 cervical joint levels in 34.1%, 3 levels in 17.1% and 4 or more levels in 20.7% of subjects. A chart review indicated that none of the referring providers reported that they had identified or suspected cervical involvement in any of the patients referred for physical therapy evaluation and treatment. Evidenced based examinations procedures identified upper cervical (Atlanto-axial) involvement in up to 74.4% of the patients, while cervical involvement between C2-C3 and C5-C6 was found in n = 59 (72%) of the patients referred for physical therapy. Referral statistics by provider and diagnosis are located in Table 1. Table 2 describes the prevalence of cervical mobility restrictions by referring diagnosis.

This study found a higher number of women, 70.7%, were referred to physical therapy with complaints of dizziness/vertigo as compared to men. This is the second and much larger study conducted by the authors which describes prospectively the prevalence, up to 74.4% with evidence of Atlanto-Axial mobility restrictions. It is the first to report that 72% displayed cervical mobility restrictions from C2-C3 to C4-C5 in those patients referred to physical therapy with a diagnosis of dizziness, vertigo, BPPV or concussion. It is the first to comprehensively report on mobility restrictions extending from the Atlanto-axial joint down to the fifth cervical vertebrae in patients referred to physical therapy with the targeted diagnoses. The authors previously used the gold standard manual assessment of upper cervical mobility the [SupFRT] [18] and compared it to a similar test that performed the maneuver in the seated position, the seated cervical flexion and rotation test [SeatFRT] [7]. Their previous study found that 56.5% of the patient referred to physical therapy displayed a positive SupFRT while 60.9% demonstrated decreased mobility with the SeatFRT [7]. In both studies, the SeatFRT identified a greater number of subjects with upper cervical mobility restrictions as compared to the SupFRT. This disparity, despite both tests being statistically identical, may be due to the fact that the SeatFRT is performed with the cervical spine loaded due to gravity while gravity is presumed to be lessened when the subject is lying supine and the head is passively flexed during the SupFRT maneuver by the clinician. Perhaps the weight bearing nature of the SeatFRT influences joint mobility greater than the relatively unweighted SupFRT and allows it to be slightly more sensitive to mobility restrictions. Future research and computer modeling should be conducted to determine if in fact it is the weight of the head pressing down on the neck compressing the joints and tissues is responsible for this difference. Future researchers may want to compare the two tests using advanced diagnostic devices such functional MRI or fluoroscopy to determine the exact cause of this and if one is more clinically relevant than the other.

The inclusion of additional cervical levels which He et al. [9] demonstrated have direct afferent input into the vestibulospinal nucleus [9] may account for the increased percentage of subjects demonstrating cervical mobility restrictions as compared to the authors’ first study. Identifying the overall high prevalence, n = 59 (72%), of cervical mobility restrictions at the C2 to C5 level in those referred to physical therapy with the diagnosis of dizziness/vertigo, or concussion does not imply causation. It simply indicates that there are regions of the cervical spine, which are not moving normally. This in turn is postulated to create abhorrent afferent input into the vestibulospinal nucleus, which may be leading to the patient’s subjective complaints of dizziness and vertigo. What this high prevalence does indicate however, is that there is now ample evidence suggesting that physical therapists and other medical providers should assess for cervical spine mobility restriction from the Atlanto-axial joint downward to C5 vertebra much earlier in the examination process. In this manner, any mobility restriction in the region and be identified and addressed in the rehabilitation process in order to quickly and safely reduce abhorrent afferent input which may be causing the patient’s symptoms of dizziness, vertigo or concussion.

Future randomized controls studies should be used to clearly define whether cervical mobility restrictions can cause symptoms associated with dizziness, vertigo, concussion or post-concussion syndrome. Treleaven et al’s [19] article would suggest that future studies also include the cervical torsion test and the cervical differentiation tests. As they appear to offer a useful clinical examination of cervical involvement in these patients. It is unfortunate that we were unable to include the cervical torsion test nor the cervical differentiation test into this current study as we feel it would have enabled us to definitively state cervical causation in our subjects rather than just prevalence. The need for early identification and treatment of the cervical spine in these patients is especially important when one considers the number of articles which have reported improvements in those diagnosed with dizziness, vertigo, concussion and post-concussion syndrome when cervical mobility is improved or restored [12–14, 16, 17, 20, 21]. The authors are currently attempting to develop an ethical approach to a randomized controlled trial to determine the efficacy of identifying cervical mobility restrictions using the techniques described in this study and the recommendations of Treleaven et al. [19] and utilizing manual interventions in the initial few weeks versus standard vestibular therapy care in order to identify causation and treatment prioritization.

While this is the first prospective study to explore cervicogenic involvement in those referred to physical therapy with a diagnosis of dizziness, vertigo, BPPV or Concussion on such a large scale, a retrospective study of 1,000 subjects determined that 89% of their symptoms could be attributed to cervicogenic dizziness [22]. This higher percentage of subjects who the authors attributed the cervical spine to be the cause of their symptoms may be due to the fact that in that this study utilized degenerative findings seen in diagnostic imaging as a positive indicator of cervical involvement [22] and the current study did not.

While a limited number of subjects who took part in this study were referred with a diagnosis of concussion. 90% demonstrated cervical mobility restrictions. This percentage is similar to another published study of subjects with concussion, in which the authors reported a similarly high prevalence of cervical impairments 82.9% [23] as compared to our 90%. This study used a similar set of assessments, SupFRT and joint mobility assessments, to identify the presence of cervical involvement [23]. A third study of 72 individuals post mild traumatic brain injury found in 73% of subjects how continued to report symptoms between 1 and 6 months post injury [8]. With cervical involvement now being reported in multiple studies and at or above 73% in subjects diagnosed with concussion, the importance of assessing cervical mobility in those with a suspected concussion should be clear [8]. The authors recommended that cervical spine mobility be assessed and addressed as early as possible in those suffering from an apparent concussion or presenting with concussive like symptoms as the neck is often involved. Future research should determine which diagnostic tests could efficaciously and comfortably employed early in the assessment of those diagnosed with concussion so that any impairments found can be quickly addressed.