[Clinical significance of cervico-ocular reactions]

The Bárány Society position on 'Cervical Dizziness'

This paper describes the Bárány Society Classification OverSight Committee (COSC) position on Cervical Dizziness, sometimes referred to as Cervical Vertigo. This involved an initial review by a group of experts across a broad range of fields, and then subsequent review by the Bárány Society COSC. Based upon the so far published literature, the Bárány Society COSC takes the view that the evidence supporting a mechanistic link between an illusory sensation of self-motion (i.e. vertigo - spinning or otherwise) and neck pathology and/or symptoms of neck pain - either by affecting the cervical vertebrae, soft tissue structures or cervical nerve roots - is lacking. When a combined head and neck movement triggers an illusory sensation of spinning, there is either an underlying common vestibular condition such as migraine or BPPV or less commonly a central vestibular condition including, when acute in onset, dangerous conditions (e.g. a dissection of the vertebral artery with posterior circulation stroke and, exceedingly rarely, a vertebral artery compression syndrome). The Committee notes, that migraine, including vestibular migraine, is by far, the commonest cause for the combination of neck pain and vestibular symptoms. The committee also notes that since head movement aggravates symptoms in almost any vestibular condition, the common finding of increased neck muscle tension in vestibular patients, may be linked as both cause and effect, to reduced head movements. Additionally, there are theoretical mechanisms, which have not been explored, whereby cervical pain may promote vaso-vagal, cardio-inhibitory reflexes and hence by presyncopal mechanisms, elicit   transient   disorientation and/or imbalance. The committee accepts that further research is required to answer the question as to whether those rare cases in which neck muscle spasm is associated with a vague sense of spatial disorientation and/or imbalance, is indeed linked to impaired neck proprioception. Future studies should ideally be placebo controlled and double-blinded where possible, with strict inclusion and exclusion criteria that aim for high specificity at the cost of sensitivity. To facilitate further studies in "cervical dizziness/vertigo", we provide a narrative view of the important confounds investigators should consider when designing controlled mechanistic and therapeutic studies. Hence, currently, the Bárány COSC refrains from proposing any preliminary diagnostic criteria for clinical use outside a research study. This position may change as new research evidence is provided.

Tonic Investigation Concept of Cervico-vestibular Muscle Afferents

Introduction Interdisciplinary research has contributed greatly to an improved understanding of the vestibular system. To date, however, very little research has focused on the vestibular system's somatosensory afferents. To ensure the diagnostic quality of vestibular somatosensory afferent data, especially the extra cranial afferents, stimulation of the vestibular balance system has to be precluded.

Objective Sophisticated movements require intra- and extra cranial vestibular receptors. The study's objective is to evaluate an investigation concept for cervico-vestibular afferents with respect to clinical feasibility.

Methods A dedicated chair was constructed, permitting three-dimensional trunk excursions, during which the volunteer's head remains fixed. Whether or not a cervicotonic provocation nystagmus (c-PN) can be induced with static trunk excursion is to be evaluated and if this can be influenced by cervical monophasic transcutaneous electrical nerve stimulation (c-TENS) with a randomized test group. 3D-video-oculography (VOG) was used to record any change in cervico-ocular examination parameters. The occurring nystagmuses were evaluated visually due to the small caliber of nystagmus amplitudes in healthy volunteers.

Results The results demonstrate: no influence of placebo-controlled c-TENS on the spontaneous nystagmus; a significant increase of the vertical nystagmus on the 3D-trunk-excursion chair in static trunk flexion with cervical provocation in all young healthy volunteers (n = 49); and a significant difference between vertical and horizontal nystagmuses during static trunk excursion after placebo-controlled c-TENS, except for the horizontal nystagmus during trunk torsion.

Conclusion We hope this cervicotonic investigation concept on the 3D trunk-excursion chair will contribute to new diagnostic and therapeutic perspectives on cervical pathologies in vestibular head-to-trunk alignment.

[Medicolegal assessment of post-traumatic vertigo]

Post-traumatic vertigo refers to a group of different disorders which occur following trauma, mainly closed head injury and whiplash injury of the cervical spine. Aside from headaches, vertigo is the most common symptom in this group of patients. In general, there are two main groups of patients with post-traumatic vertigo: those with documented vestibular dysfunctions and those without. The most common post-traumatic vestibular disorders are benign paroxysmal positioning vertigo, labyrinthine concussion, canal dehiscence and otolithic lesions. Some of these disorders are characterized by spontaneous improvement or recovery over weeks or months and some may also be treated effectively. A number of patients, however, develop phobic postural vertigo requiring psychiatric or psychosomatic exploration.

Benign paroxysmal positional vertigo following whiplash injury: a myth or a reality?

OBJECTIVE

The aim of the study was to evaluate the true incidence, diagnosis, and treatment of benign paroxysmal positional vertigo (BPPV) arising after whiplash injury and to distinguish this type of posttraumatic vertigo from other types of dizziness complained after trauma.

METHODS

This was a retrospective study comprising patients referred to our center after whiplash injury. The patients were evaluated with neurotologic examination including bedside and instrumental tests. A Dizziness Handicap Inventory evaluating the symptoms of patients was submitted before and after treatment and was evaluated. The BPPV patients were separately evaluated from those with cervicogenic vertigo, and a comparison between our data about idiopathic BPPV was done.

RESULTS

Eighteen patients of whiplash who had BPPV were evaluated. The mean age was 38.2 years. BPPV was the cause of vertigo in 33.9% of total whiplash patients. In 16 cases, the posterior semicircular canal was involved; the lateral semicircular canal was involved in 2 cases. The instrumental neurotologic assessment did not show any alteration of either vestibulospinal reflexes or dynamic ocular movements. Duration of symptoms before treatment ranged from 3 to 26 days. A total of 55.5% of patients had relief from their symptoms after first repositioning maneuver. The Dizziness Handicap Inventory score improved in all patients treated with repositioning maneuvers, but no difference emerged with idiopathic BPPV data.

CONCLUSION

BPPV after whiplash injury could be unveiled with a simple bedside examination of peripheral vestibular system, and a treatment could be done in the same session. The diagnosis of posttraumatic BPPV is not different from the idiopathic form, but the treatment may require more maneuvers to achieve satisfactory results.

Analysis of visually guided eye movements in subjects after whiplash injury

OBJECTIVE

The aims of present research were to analyze the visually guided eye movements of subjects suffering from the consequences of whiplash injury and the possibility to differentiate patients from feigning subject. We analyzed the role of video-nystagmography for clinical and forensic aspects.

METHODS

It was a prospective case-control study. Detailed history was taken and patients were thoroughly investigated. Smooth pursuit and saccadic eye movements were assessed in 33 patients affected by imbalance following a whiplash injury. A control group of 20 subjects was also evaluated. All tests were executed in neutral neck position and after left and right trunk rotation.

RESULTS

The t-test, applied to all parameters showed that difference of the parameter between the groups was not statistically significant.

CONCLUSION

The visually guided eye movement evaluation does not seem to offer a clinically relevant method to differentiate patients suffering from the effects of whiplash injury from normal subjects.

[Cervicoproprioceptive provocation of horizontal and vertical nystagmus in test subjects]

BACKGROUND

The cervico-ocular reflex (COR) has been confirmed in numerous animal experiments. On the other hand, its clinical assessment is disputed. Anteflexion and retroflexion of the head are among the main movements of the atlanto-occipital joint. We investigated whether these head movements produce neck proprioceptive stimulation in the vestibular system.

SUBJECTS AND METHOD

We investigated 50 students under the experimental conditions of strictly cervical provocation. The trunk was rotated, anteflexed, and retroflexed into its end positions for 60 s under video-oculographic control without changing the head-space relationship. During the cervical provocation, horizontal, vertical, or rotational nystagmus within a time window of 5-30 s after the start of the provocation was detected as a target parameter.

RESULTS

The results showed that, compared to the baseline, there was a significant increase in vertical and horizontal nystagmus after the cervical provocation. The horizontal nystagmus reaction, rather than the vertical, was increased significantly by the maximum trunk rotation. In addition, we found a significant amount of vertical rather than horizontal nystagmus under trunk flexion provocation.

CONCLUSION

Under cervical provocation of test subjects, we were able to elicit horizontal and vertical nystagmus (upbeat nystagmus) via cervico-ocular roots. Due to a neck proprioceptive activation of the vestibular system we interpret our result as a "cervico-tonic provocation nystagmus".

The cervico-ocular reflex is increased in whiplash injury patients

Whiplash-associated disorders (WAD) are a major problem in the Western world, which put a formidable financial burden on modern society and which evoke an emerging debate on the true nature of their origin. To date there is no generally accepted test that allows us to diagnose WAD objectively. Because whiplash injury causes dysfunction of proprioception in the neck, we investigated the characteristics of the cervico-ocular reflex (COR) of presumptive WAD patients. These patients and age-matched healthy controls were rotated at different stimulus peak velocities in the dark while their head was fixed in space. The gain values of the COR were significantly increased in the patient population at a wide range of stimulus peak velocities with maximum difference at the lower frequencies (p = 0.037, ANOVA). Hence, although larger numbers of patients should be measured, the COR gain appears to be a parameter that may permit an objective diagnosis of WAD.

Hyperactive VOR and hyperventilation after whiplash injury

Otoneurological and respiratory tests were performed on 32 patients after whiplash injury caused by a rear-end car collision. Oculomotor and cervico-ocular test results were generally normal. In a significantly large number of case, the vestibulo-ocular reflex (VOR) was hyperactive (n = 17; 53%) and the respiratory test results were typical of the hyperventilation syndrome (HVS) (n = 12; 38%). Hyperactive VOR and the HVS occurred significantly more often in combination (n = 7; 22%) than could be accounted for by combined false positivity. Most of the significant findings were due to high relative frequencies in the women. The hyperactive VOR might have been the result of plastic adaptation to limited head mobility secondary to neck pain. Behavioural and emotional distress might offer alternative explanations for both the hyperactive VOR and HVS.