[Vestibular compensation : basic principles and clinical significance]

Vertigo Associated With Cochlear Implant Surgery: Correlation With Vertigo Diagnostic Result, Electrode Carrier, and Insertion Angle

Objective: Vertigo is a common side effect of cochlear implant (CI) treatment. This prospective study examines the incidence of postoperative vertigo over time and aims to analyze influencing factors such as electrode design and insertion angle (IA). Study Design and Setting: This is a prospective study which has been conducted at a tertiary referral center (academic hospital). Patients: A total of 29 adults were enrolled and received a unilateral CI using one of six different electrode carriers, which were categorized into "structure-preserving" (I), "potentially structure-preserving" (II), and "not structure-preserving" (III). Intervention: Subjective vertigo was assessed by questionnaires at five different time-points before up to 6 months after surgery. The participants were divided into four groups depending on the time of the presence of vertigo before and after surgery. Preoperatively and at 6 months postoperatively, a comprehensive vertigo diagnosis consisting of Romberg test, Unterberger test, subjective visual vertical, optokinetic test, video head impulse test, and caloric irrigation test was performed. In addition, the IA was determined, and the patients were divided in two groups (<430°; ≥430°). Main Outcome Measures: The incidence of vertigo after CI surgery (group 1) was reported, as well as the correlation of subjective vertigo with electrode array categories (I-III) and IA. Results: Among the participants, 45.8% experienced new vertigo after implantation. Based on the questionnaire data, a vestibular origin was suspected in 72.7%. The results did not show a significant correlation with subjective vertigo for any of the performed tests. In group 1 with postoperative vertigo, 18% of patients showed conspicuous results in a quantitative analysis of caloric irrigation test despite the fact that the category I or II electrodes were implanted, which are suitable for structure preservation. Average IA was 404° for the overall group and 409° for group 1. There was no statistically significant correlation between IA and perceived vertigo. Conclusions: Though vertigo after CI surgery seems to be a common complication, the test battery used here could not objectify the symptoms. Further studies should clarify whether this is due to the multifactorial cause of vertigo or to the lack of sensitivity of the tests currently in use. The proof of reduced probability for vertigo when using atraumatic electrode carrier was not successful, nor was the proof of a negative influence of the insertion depth.

[Vestibular neuritis - prevalence of inpatient cases in Germany]

INTRODUCTION

The vestibular neuropathy (VN) is a frequently diagnosed, acute peripheral vestibular form of vertigo. Typical symptoms are spinning vertigo, ipsilateral tendency to fall with standing and gait insecurity, and vegetative side effects. Epidemiological studies of VN in the general population are rare and the little existing literature varies in results.

MATERIAL AND METHODS

All inpatient VN cases in Germany from 2000 to 2017 were evaluated. The data used was provided by the German Federal Statistical Office. In addition to the annual number of cases, information about age at diagnosis, gender and length of stay were evaluated.

RESULTS

Between 2000-2017, 401 242 inpatient cases with VN were reported in Germany. This translates into a prevalence of 36.7 cases/100 000 individuals in 2017. During the examined 17 years the number of cases with VN in Germany increased by approximately 180 %. Across all years evaluated, VN was observed more often among women than among men. The length of stay decreased continuously by a total of 3.3 days during the observation period.

DISCUSSION

In 2017, the observed prevalence of VN cases in Germany was 36.7 hospital cases/100 000 individuals. Literature shows a prevalence of non-hospitalized VN cases of 162/100 000 individuals in 2015. Even when taking into account an inaccuracy due to a possible bias, these numbers add up to a much higher prevalence of VN cases than described previously in the literature. The continuous increase in cases with VN in Germany may be associated with demographic changes in age structure and a related higher morbidity.

Objective evaluation of neck muscle tension and static balance in patients with chronic dizziness

CONCLUSION

Increase in the average value of bilateral neck muscle tension (ANT) indicates the increase in neck muscle tension to stabilize static posture resulting from vestibular compensation. Asymmetry of neck muscle tension was closely related to postural imbalance.

OBJECTIVE

Patients with dizziness often complain of neck symptoms with stiff neck. This study was conducted to clarify the pathophysiological mechanism of neck symptoms in patients with dizziness.

METHODS

We objectively measured bilateral trapezius muscle tension in patients with chronic dizziness and determined its relationship with static postural perturbation. The study included 26 patients with chronic dizziness caused by unilateral vestibular deficit and 24 healthy controls. The tension of bilateral trapezius muscles was objectively measured using a neck muscle tension meter. ANT and the ratio (right/left) of the bilateral neck muscle tension (RNT) were calculated. Static posturography was performed to measure total length of path (LNG).

RESULTS

ANT was negatively correlated to LNG under the eyes closed (EC) condition only in the case of the patients (r = -0.44, p < 0.05). In the case of both the controls and the patients with a unilateral vestibular deficit, RNT was positively correlated to LNG under the EC condition.

Influence of cervical spine stabilization via Stiff Neck on the postural system in healthy patients: compensation or decompensation of the postural system?

Functional and structural disorders of the cervical spine are often regarded as the cause of non-specific vertigo. Pathogenetically, disorders of proprioceptive connections between neck muscles and vestibular cores as well as the proprioceptors in the cervical facette joints are presumed. According to a study by Hülse and Hölzl (HNO 48:295-301, 1), after manual therapeutic intervention in patients with functional disorders of the cervical spine 50% of the probands stated a significant reduction of their vertigo. This was backed up in posturography, which documented an improvement in vestibulospinal reactions. To date, the effects of artificial as well as surgical stabilization of the cervical spine on the balance system have not been explored yet. In a first pilot study, we examined the influence of artificial stabilization of the cervical spine via cervical collar Stiff Neck, manufactured by Ambu/Perfit ACE] on the balance system of 20 healthy probands. For this purpose, a posturography (Balance Master Systems, NeuroCom, Clackamas, OR, USA) was applied to 20 healthy probands (10 males, 10 females) with a mean age of 35 years who had no prior spine pathology. Posturography was analyzed under static and dynamic test situations with and without Stiff Neck cervical collar. The results were compared statistically to the Wilcoxon test. In the static test situation of the modified clinical test of sensory interaction on balance, a significantly improved standing stability occurred. In none of the dynamic tests did fixation of the cervical spine by Stiff Neck cuff lead to a measurable impairment of the movement coordination. All probands felt subjectively more stable when wearing the Stiff Neck. In healthy probands, a fixation of the cervical spine leads to a stabilization of the postural balance situation. This fixation seems to be helpful in compensating the malfunction of other components of balance information. In a next step, this same model of analysis is applied to patients with cervical instability. Standing stability and movement coordination before and after cervical fusion are being explored.