Long-Term Vestibular Outcomes in Cochlear Implant Recipients

Background: Vestibular dysfunction is likely the most common complication to cochlear implantation (CI) and may, in rare cases, result in persistent severe vertigo. Literature on long-term vestibular outcomes is scarce.Objective: This paper aims to evaluate vestibular dysfunction before and after cochlear implantation, the long-term vestibular outcomes, and follows up on previous findings of 35 consecutive adult cochlear implantations evaluated by a battery of vestibular tests.Methods: A prospective observational longitudinal cohort study was conducted on 35 CI recipients implanted between 2018 and 2019; last follow-up was conducted in 2021. At the CI work-up (T0) and two postoperative follow-ups (T1 and T2), 4 and 14 months following implantation, respectively, all patients had their vestibular function evaluated. Evaluation with a vestibular test battery, involving video head impulse test (vHIT), cervical vestibular evoked myogenic potentials (cVEMP), caloric irrigation test, and dizziness handicap inventory (DHI), were performed at all evaluations.Results: vHIT testing showed that 3 of 35 ears had abnormal vHIT gain preoperatively, which increased insignificantly to 4 of 35 at the last follow-up (p = 0.651). The mean gain in implanted ears decreased insignificantly from 0.93 to 0.89 (p = 0.164) from T0 to T2. Preoperatively, 3 CI ears had correction saccades, which increased to 11 at T2 (p = 0.017). Mean unilateral weakness increased from 19 to 40% from T0 to T2 (p < 0.005), and the total number of patients with either hypofunctioning or areflexic semicircular canals increased significantly from 7 to 17 (p < 0.005). Twenty-nine percent of CI ears showed cVEMP responses at T0, which decreased to 14% (p = 0.148) at T2. DHI total mean scores increased slightly from 10.9 to 12.8 from T0 to T1 and remained at 13.0 at T2 (p = 0.368). DHI scores worsened in 6 of 27 patients and improved in 4 of 27 subjects from T0 to T2.Conclusion: This study reports significant deterioration in vestibular function 14 months after cochlear implantation, in a wide range of vestibular tests. vHIT, caloric irrigation, and cVEMP all measured an overall worsening of vestibular function at short-term postoperative follow-up. No significant deterioration or improvement was measured at the last postoperative follow-up; thus, vestibular outcomes reached a plateau. Despite vestibular dysfunction, most of the patients report less or unchanged vestibular symptoms.

Clinical dynamic visual acuity in patients with cerebellar ataxia and vestibulopathy

Deterioration of dynamic visual acuity (DVA) as a result of impaired vestibulo-ocular reflex (VOR) has been well described in peripheral vestibulopathies, however, changes in DVA in patients with degenerative cerebellar ataxias (CA) and its relation to VOR impairment in these patients has not yet been evaluated. Our aim was to assess the alterations of DVA in CA and to evaluate its relation to vestibular function. 32 patients with CA and 3 control groups: 13 patients with unilateral and 13 with bilateral vestibulopathy and 21 age matched healthy volunteers were examined by clinical DVA test, VOR was assessed by video Head Impulse Test and caloric irrigation. The severity of ataxia in CA was assessed by Scale for the assessment and rating of ataxia (SARA). Relationship between DVA and vestibular function in CA patients was examined by linear regressions. DVA impairment was highly prevalent in CA patients (84%) and its severity did not differ between CA and bilateral vestibulopathy patients. The severity of DVA impairment in CA was linked mainly to VOR impairment and only marginally to the degree of ataxia. However, DVA impairment was present also in CA patients without significant vestibular lesion showing that central mechanisms such as impairment of central adaptation of VOR are involved. We suggest that the evaluation of DVA should be a standard part of clinical evaluation in patients with progressive CA, as this information can help to target vestibular and oculomotor rehabilitation.

VESTIBULAR TESTING IN CHILDREN WITH DIZZINESS AND BALANCE CONCERNS AFTER CONCUSSION: LABORATORY AND CLINICAL RESULTS

Background: Dizziness is the second most common symptom in people who sustain a concussion and there are few reports on vestibular laboratory findings in the concussed pediatric population. Studies to date have shown conflicting findings regarding incidence of peripheral vestibular disorders. Hypothesis/Purpose: The purpose of this study is to report vestibular laboratory and clinical examination findings in concussed youth referred to a multidisciplinary vestibular clinic. Methods: A retrospective chart review was performed for all patients (n=474) seen from August 2017 to March 2020 for a single comprehensive examination in a multidisciplinary pediatric vestibular specialty clinic. Data was extracted from the charts of patients (n=64) with a history of concussion referred because of chronic dizziness and/or imbalance. Each patient was examined by a neurotologist, physical therapist, and audiologist with specialized training in vestibular disorders. Vestibular laboratory testing performed by audiologists included video nystagmography (VNG) evaluation of oculomotor function and BPPV, rotational chair, video head impulse test (vHIT), vestibular evoked myogenic potentials (VEMPs), post-headshake nystagmus, and caloric irrigation. Physical therapy clinical examination included dynamic visual acuity testing (DVA), vestibular/oculomotor screening (VOMS), and sensory organization test (SOT). Not all tests were performed on every patient secondary to factors such as insurance coverage, patient tolerance, and young age. Results: 1 or more components of VOMS was abnormal in 30 of 53 patients examined. DVA was completed on 40 patients, 23 of which were reported as abnormal. SOT was completed on 46 patients, 18 of which demonstrated below normal composite equilibrium scores. Laboratory findings were as follows: VEMPs (n=50) were normal in all but 1 patient, vHIT (n=59), caloric irrigation (n=26), post-headshake nystagmus (n=49), and positional testing (n=55) were normal on all patients tested. Rotational chair (n=60) was performed at 4 different frequencies and revealed low gain in 3 patients. Conclusion: Vestibular laboratory examination was normal in nearly all subjects tested. These results suggest that in concussed youth with chronic dizziness and/or imbalance, laboratory vestibular test outcomes indicative of peripheral dysfunction are rare, which contradicts previous research in this population. In contrast, clinical vestibular assessment was abnormal in more than 50% of subjects examined which suggests that clinicians should use caution interpreting clinical examination findings for diagnosing peripheral vestibular dysfunction. Abnormal clinical examination findings may be indicative of central vestibular conditions such as space and motion intolerance and PPPD in chronically dizzy pediatric patients after concussion. Tables/Figures: [Table: see text][Table: see text]

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.

Assessment of Vestibular and Oculomotor Function in Patients with Vestibular Migraine: A Preliminary Study

Background: The purpose of the study is to assess the vestibular and oculomotor function in patients with vestibular migraine(VM).And we also investigate the relationship between test resultsandeffectiveness of prophylactic medication.Methods: We recruited 41 patientswith VM. They were examinedwith vestibular-evoked myogenic potentials(VEMP), video head impulse test(vHIT) and videonystagmography(VNG), including spontaneous or positional nystagmus, gaze-evoked nystagmus, smooth pursuit and caloric irrigation testing.All VM patients were treated withprophylactic medications. Theintensity of vertigo were evaluated with dizziness handicap inventory(DHI) before and after treatment. After 6 months, we evaluate the effectiveness of prophylactic medication. We analyzed the relationship between test resultsandeffectiveness of prophylactic medication.Results:In vestibular function test,71% of VM patients showed abnormal result. 20% showed abnormal air-conducted cVEMP and 42% showed abnormal air-conducted oVEMP. 32% showed abnormal vHIT and 56% showed abnormal caloric irrigation test.The abnormal rate of oVEMP was significantly higher than cVEMP (p<0.05). And the abnormal rate of caloric irrigation test was significantly higher than vHIT(p<0.05). In oculomotor function test, 42% showed pathological result. The abnormal rate of oculomotor function test was significantly lower than vestibular function test (p<0.05). After 6 months follow-up, rate of good effectiveness was significantly higher in normal vestibular function test group compared with the abnormal vestibular function test group (p<0.05). Rate of good effectiveness was no statistically significant difference between normal oculomotor function test group and abnormal oculomotor function test group (p>0.05).Conclusions: Abnormal vestibular and oculomotor function are commonly observed in VM patients. And VM patients with abnormal vestibular function have a weak effectiveness of prophylaxis medications.

Worldwide survey on laboratory testing of vestibular function

BackgroundThe function of the peripheral vestibular system can nowadays be quantified. The video head impulse test (vHIT) and caloric irrigation are used for the semicircular canals, cervical vestibular evoked myogenic potentials (cVEMP) for the sacculus, and ocular vestibular evoked myogenic potentials (oVEMP) for the utriculus. Because there is no agreement on normal and pathologic values, we performed a worldwide survey.MethodsA web-based standardized survey questionnaire was used to collect data on “reference values” and “cutoff” values. Thirty-eight centers from all continents (except Africa) replied.Results“Reference values”: vHIT: mean for the vestibulo-ocular reflex gain of the left horizontal canal 0.91 (range: 0.7–1.01) and of the left horizontal canal 0.92 (0.7–1.05); side difference 0.15 (0.25–0.3). Caloric irrigation: mean peak slow phase velocity of caloric-induced nystagmus for warm (44°C) water 18.65°/s (12–30°/s); cold (30°C) water 18.21°/s (10–25°/s). cVEMP: P13-N23 amplitude mean for the lower limit 28.67 μV (16–50 μV); upper limit 200 μV (50–350 μV). “Cutoff values”: vHIT: side difference 0.26 (0.1–0.4), bilateral vestibulopathy <0.61 (0.3–0.8); unilateral vestibulopathy (UVP) <0.68 (0.4–0.8). Caloric irrigation pathologic side difference mean 25.93% (17.7%–40%) or 12°/sec (5–30°/s); side difference UVP 26.73% (20%–40%) or 29.8°/s (5–100°/s). cVEMP: P13/N23 amplitude mean lower cutoff 32.5 μV (15–50 μV), mean upper cutoff 125 μV (50–200 μV), asymmetry 36.08 μV (20–50 μV).ConclusionThis worldwide survey showed a large variability in terms of reference and pathologic cutoff values in the 38 centers included. Therefore, standardization of how to achieve these values and agreement on which values should be used is highly warranted to guarantee a high quality of vestibular testing and interpretation of clinical and scientific results.

Diagnose und Differenzialdiagnose von peripheren und zentralen Schwindelsyndromen

The diagnosis of the various peripheral and central vestibular disorders is mainly based on the patient history (time course, type of symptoms, modulating factors, and accompanying symptoms) and a systematic clinical examination of the vestibular, ocular motor, and cerebellar systems (examination for nystagmus, head impulse test, positional maneuvers, Romberg test and examination for central ocular motor signs). The two most important laboratory tests are the “video-head impulse test” and caloric irrigation. Fortunately, the diagnosis of vestibular disorders has become easier and more precise as a result of the very clinically oriented diagnostic criteria of the Bárány Society (www.jvr-web.org/ICVD.html).