Vestibular PREHAB and gentamicin before schwannoma surgery may improve long-term postural function

Effect of vestibular loss on head-on-trunk stability in individuals with vestibular schwannoma

The vestibulo-collic reflex generates neck motor commands to produce head-on-trunk movements that are essential for stabilizing the head relative to space. Here we examined the effects of vestibular loss on head-on-trunk kinematics during voluntary behavior. Head and trunk movements were measured in individuals with vestibular schwannoma before and then 6 weeks after unilateral vestibular deafferentation via surgical resection of the tumor. Movements were recorded in 6 dimensions (i.e., 3 axes of rotation and 3 axes of translation) using small light-weight inertial measurement units while participants performed balance and gait tasks. Kinematic measures differed between individuals with vestibular schwannoma (at both time points) and healthy controls for the more challenging exercises, namely those performed in tandem position or on an unstable surface without visual input. Quantitative assessment of the vestibulo-ocular reflex (VOR) revealed a reduction in VOR gain for individuals with vestibular schwannoma compared to control subjects, that was further reduced following surgery. These findings indicated that the impairment caused by either the tumor or subsequent surgical tumor resection altered head-on-trunk kinematics in a manner that is not normalized by central compensation. In contrast, we further found that head-on-trunk kinematics in individuals with vestibular schwannoma were actually comparable before and after surgery. Thus, taken together, our results indicate that vestibular loss impacts head-on-trunk kinematics during voluntary balance and gait behaviors, and suggest that the neural mechanisms mediating adaptation alter the motion strategies even before surgery in a manner that may be maladaptive for long-term compensation.

Improved Recovery after Vestibular Schwannoma Excision with Intratympanic Gentamicin Prehabilitation

OBJECTIVE

Translabyrinthine excision of a vestibular schwannoma is associated with acute vestibular failure. Preoperative intratympanic gentamicin (ITG) injections can improve objective balance function after surgery but its clinical benefits remain to be established.

METHODS

Adult patients undergoing translabyrinthine removal of a vestibular schwannoma between January 2014 and February 2018 underwent preoperative vestibular function testing. Patients were divided in to 3 groups, those with vestibular function (VF) who received ITG injections, those with VF but did not receive ITG and those with no VF. Groups were compared according to degree of vertigo, length of stay, time to unassisted mobilization, and postoperative anti-emetic consumption.

RESULTS

Forty six patients had ITG injections (Group 1), 7 had residual VF but refused treatment (Group 2), 21 had no VF (Group 3). Group 1 had a significant improvement in vertigo over time whereas groups 2 and 3 did not. There was a statistically significant 70% decrease in time to independent mobilization between Group 1 and other groups and a 19% decrease in length of stay in Group 1 compared to other groups although this did not reach statistical significance. Two patients had injection-related complications. Group 1 used less anti-emetics than other groups but this was not statistically significant.

CONCLUSION

Preoperative intratympanic gentamicin injection with vestibular rehabilitation exercises is associated with less postoperative vertigo and earlier postoperative mobilization. There was reduced duration of hospitalization and decreased consumption of anti-emetic but not significantly so possibly because of low numbers of patients in the no treatment group.

LEVEL OF EVIDENCE

2 Laryngoscope, 2024.

The effect of intratympanic gentamicin as a prehabilitation strategy for objective and subjective vestibular function in patients undergoing microsurgery for a unilateral vestibular schwannoma

OBJECTIVE

To review the literature on intratympanic gentamicin treatment as prehabilitation for patients undergoing surgery for a unilateral vestibular schwannoma.

DATA SOURCES

A systematic literature search was conducted up to March 2023 in Pubmed, Embase, Cochrane, Web of Science, Academic Search Premier, Google Scholar and Emcare databases.

REVIEW METHODS

Articles on the effect of intratympanic gentamicin followed by vestibular schwannoma surgery were reviewed. Data on objective vestibular function and subjective outcomes were compiled in tables for analysis. Relevance and methodological quality were assessed with the methodological index for non-randomized tool.

RESULTS

A total of 281 articles were identified. After screening and exclusion of duplicates, 13 studies were reviewed for eligibility, of which 4 studies could be included in the review. The posturography test, the subjective visual horizontal test, and the optokinetic nystagmus test showed decreased vestibular function in the group of patients who received intratympanic gentamicin before microsurgery compared to the group of patients without gentamicin. Other objective tests did not show significant differences between patient groups. Subjective vestibular outcomes, as evaluated by questionnaires on quality of life and/or dizziness, did not seem to improve from intratympanic gentamicin pretreatment.

CONCLUSION

Vestibular schwannoma patients who received intratympanic gentamicin before surgical resection of the tumor performed better in the posturography test, subjective visual horizontal test, and the optokinetic nystagmus test afterwards. However, studies that also evaluated subjective outcomes such as dizziness, anxiety, depression, and balance self-confidence did not show a positive effect of intratympanic gentamicin on the vestibular complaints and symptoms.

Pre-habilitation with intratympanic gentamicin in vestibular schwannomas: a systematic review

OBJECTIVE

To assess whether pre-habilitation with intratympanic gentamicin can accelerate vestibular compensation following vestibular schwannoma resection.

METHODS

Seventeen studies were retrieved from the databases Medline, PubMed, Frontiers, Cochrane Library, Cambridge Core and ScienceDirect. Eight of the 17 studies met our criteria; the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used. Heterogeneity, risk of bias and effect on post-operative recovery were assessed.

RESULTS

Four of the eight studies showed a statistically positive effect of pre-habilitation with gentamicin on the post-operative recovery process; the remainder also reported benefits, although not statistically significant. No study reported negative effects. Limitations were linked mostly to the limited number of enrolled patients and the outcome assessment methods.

CONCLUSION

Fifty per cent of the studies found a statistically positive effect of pre-habilitation with gentamicin prior to vestibular schwannoma resection. While the results are promising, due to the limited numbers further prospective studies are required to strengthen the evidence.

Subjective perception of activity level: A prognostic factor for developing chronic dizziness after vestibular schwannoma resection?

Introduction

A vestibular schwannoma (VS) resection causes an acute unilateral vestibular deafferentation resulting in acute postoperative symptoms. Despite the expected resolution of most of the symptoms, due to central vestibular compensation, more than one out of four patients develop chronic dizziness. Several predictive factors, such as age and tumor size, have been suggested. Despite its potential effect on the process of central vestibular compensation, the level of physical activity after VS resection was not yet considered. Therefore, the association between the level of physical activity and chronic dizziness after VS resection will be investigated.

Methods

This retrospective cohort study included 66 patients who underwent a retro-sigmoid VS resection between October 2001 and February 2007. Patients were assessed before surgery and at 9 weeks and 6 months postoperatively. At 9 weeks, patients were asked to report their level of physical activity (PA) during the past week by using a visual analogue scale and their balance performance was assessed by four standing balance conditions with eyes closed and the Timed Up and Go test (TUG). Based on the Dizziness Handicap Inventory (DHI) score at 6 months, patients were divided in a chronic dizziness group (DHI > 30) and non-chronic dizziness group (DHI-score ≤ 30). Age, sex, Koos classification, preoperative vestibular function, treatment group, balance performance, and level of PA were compared between both groups and used as independent variables in linear regression analyses with the DHI score at 6 months as dependent variable.

Results

The chronic dizzy patients revealed to have significantly lower levels of PA (p < 0.001) and worse static and dynamic balance performance (p = 0.023 and p = 0.041, respectively) 9 weeks after surgery. After elimination, the multiple regression analysis resulted in a model with two variables (PA level, TUG) which significantly predicted the DHI score (F_2,42 = 6.581; R² = 0.239; p = 0.003).

Conclusion

This study revealed associations between (1) the level of PA and balance performance in the subacute phase and (2) chronic dizziness after VS resection. Assessment of the level of PA and balance performance during the subacute phase, which can be performed in a non-invasive and non-time-consuming way, might therefore provide prognostic information after VS resection.

Rehabilitation of Individuals With Cancer

The survival rate of cancer is increasing as treatment improves. As patients with cancer now live longer, impairments may arise that impact quality of life (QOL) and function. Therefore, a focus on QOL is often as important as survival. An interdisciplinary team can achieve goal-oriented and patient-centered rehabilitation, which can optimize function and QOL, and minimize impairments, restrictions, and activity limitations. In most cases, cancer patients must be active participants in therapy and exhibit carryover. Patients with cancer often have impairments that include fatigue, pain, brain fog, impaired cognition, paresis, mood disorders, difficulty with activities of daily living (ADL), bowel/bladder/sexual dysfunction, and bone and soft tissue involvement. Adaptive equipment, exercise, and ADL training can mitigate restrictions on activity. The trajectory and phase of the disease along the continuum of cancer care may influence the goals of rehabilitation in that time window. QOL is often influenced by participation in vocational, recreational, and home-based activities. A holistic perspective should include an analysis of distress, socioeconomic barriers, and transportation limitations when addressing issues.

Vestibular Rehabilitation for Peripheral Vestibular Hypofunction: An Updated Clinical Practice Guideline From the Academy of Neurologic Physical Therapy of the American Physical Therapy Association

Background:

Uncompensated vestibular hypofunction can result in symptoms of dizziness, imbalance, and/or oscillopsia, gaze and gait instability, and impaired navigation and spatial orientation; thus, may negatively impact an individual's quality of life, ability to perform activities of daily living, drive, and work. It is estimated that one-third of adults in the United States have vestibular dysfunction and the incidence increases with age. There is strong evidence supporting vestibular physical therapy for reducing symptoms, improving gaze and postural stability, and improving function in individuals with vestibular hypofunction. The purpose of this revised clinical practice guideline is to improve quality of care and outcomes for individuals with acute, subacute, and chronic unilateral and bilateral vestibular hypofunction by providing evidence-based recommendations regarding appropriate exercises.

Methods:

These guidelines are a revision of the 2016 guidelines and involved a systematic review of the literature published since 2015 through June 2020 across 6 databases. Article types included meta-analyses, systematic reviews, randomized controlled trials, cohort studies, case-control series, and case series for human subjects, published in English. Sixty-seven articles were identified as relevant to this clinical practice guideline and critically appraised for level of evidence.

Results:

Based on strong evidence, clinicians should offer vestibular rehabilitation to adults with unilateral and bilateral vestibular hypofunction who present with impairments, activity limitations, and participation restrictions related to the vestibular deficit. Based on strong evidence and a preponderance of harm over benefit, clinicians should not include voluntary saccadic or smooth-pursuit eye movements in isolation (ie, without head movement) to promote gaze stability. Based on moderate to strong evidence, clinicians may offer specific exercise techniques to target identified activity limitations and participation restrictions, including virtual reality or augmented sensory feedback. Based on strong evidence and in consideration of patient preference, clinicians should offer supervised vestibular rehabilitation. Based on moderate to weak evidence, clinicians may prescribe weekly clinic visits plus a home exercise program of gaze stabilization exercises consisting of a minimum of: (1) 3 times per day for a total of at least 12 minutes daily for individuals with acute/subacute unilateral vestibular hypofunction; (2) 3 to 5 times per day for a total of at least 20 minutes daily for 4 to 6 weeks for individuals with chronic unilateral vestibular hypofunction; (3) 3 to 5 times per day for a total of 20 to 40 minutes daily for approximately 5 to 7 weeks for individuals with bilateral vestibular hypofunction. Based on moderate evidence, clinicians may prescribe static and dynamic balance exercises for a minimum of 20 minutes daily for at least 4 to 6 weeks for individuals with chronic unilateral vestibular hypofunction and, based on expert opinion, for a minimum of 6 to 9 weeks for individuals with bilateral vestibular hypofunction. Based on moderate evidence, clinicians may use achievement of primary goals, resolution of symptoms, normalized balance and vestibular function, or plateau in progress as reasons for stopping therapy. Based on moderate to strong evidence, clinicians may evaluate factors, including time from onset of symptoms, comorbidities, cognitive function, and use of medication that could modify rehabilitation outcomes.

Discussion:

Recent evidence supports the original recommendations from the 2016 guidelines. There is strong evidence that vestibular physical therapy provides a clear and substantial benefit to individuals with unilateral and bilateral vestibular hypofunction.

Limitations:

The focus of the guideline was on peripheral vestibular hypofunction; thus, the recommendations of the guideline may not apply to individuals with central vestibular disorders. One criterion for study inclusion was that vestibular hypofunction was determined based on objective vestibular function tests. This guideline may not apply to individuals who report symptoms of dizziness, imbalance, and/or oscillopsia without a diagnosis of vestibular hypofunction.

Disclaimer:

These recommendations are intended as a guide to optimize rehabilitation outcomes for individuals undergoing vestibular physical therapy. The contents of this guideline were developed with support from the American Physical Therapy Association and the Academy of Neurologic Physical Therapy using a rigorous review process. The authors declared no conflict of interest and maintained editorial independence.

Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A369).

Pre-habilitation Before Vestibular Schwannoma Surgery-Impact of Intratympanal Gentamicin Application on the Vestibulo-Ocular Reflex

Background: Patients with vestibular schwannoma that show residual peripheral-vestibular function before surgery may experience sudden and substantial vestibular loss of function after surgical resection. To alleviate the sudden loss of peripheral-vestibular function after vestibular-schwannoma (VS) resection, pre-surgical intratympanic gentamicin application was proposed. Objective: We hypothesized that this approach allows for a controlled reduction of peripheral-vestibular function before surgery but that resulting peripheral-vestibular deficits may be canal-specific with anterior-canal sparing as observed previously in systemic gentamicin application. Methods: Thirty-four patients (age-range = 27-70 y) with unilateral VS (size = 2-50 mm) were included in this retrospective single-center trial. The angular vestibulo-ocular reflex (aVOR) was quantified before and after (29.7 ± 18.7 d, mean ± 1SD) a single or two sequential intratympanic gentamicin applications by use of video-head-impulse testing. Both aVOR gains, cumulative saccadic amplitudes, and overall aVOR function were retrieved. Statistical analysis was done using a generalized linear model. Results: At baseline, loss of function of the horizontal (20/34) and posterior (21/34) canal was significantly (p < 0.001) more frequent than that of the anterior canal (5/34). After gentamicin application, loss of function of the horizontal (32/34) or posterior (31/34) canal remained significantly (p ≤ 0.003) more frequent than that of the anterior canal (18/34). For all ipsilesional canals, significant aVOR-gain reductions and cumulative-saccadic-amplitude increases were noted after gentamicin. For the horizontal canal, loss of function was significantly larger (increase in cumulative-saccadic-amplitude: 1.6 ± 2.0 vs. 0.8 ± 1.2, p = 0.007) or showed a trend to larger changes (decrease in aVOR-gain: 0.24 ± 0.22 vs. 0.13 ± 0.29, p = 0.069) than for the anterior canal. Conclusions: Intratympanic gentamicin application resulted in a substantial reduction in peripheral-vestibular function in all three ipsilesional canals. Relative sparing of anterior-canal function noted at baseline was preserved after gentamicin treatment. Thus, pre-surgical intratympanic gentamicin is a suitable preparatory procedure for reducing the drop in peripheral-vestibular function after VS-resection. The reasons for relative sparing of the anterior canal remain unclear.

Assessment of visual sensation, psychiatric profile and quality of life following vestibular schwannoma surgery in patients prehabituated by chemical vestibular ablation

AIMS

Preoperative chemical vestibular ablation can reduce vestibular symptoms in patients who have gone through vestibular schwannoma resection. The goal of this study was to determine whether chemical vestibular prehabituation influences the patients' post-operative perception of visual stimulation, mental status and quality of life. We also tried to find out whether increases of optokinetic nystagmus, measured by routine electronystagmography, correlate with subjective symptoms.

METHODS

We preoperatively administered (2 months prior to surgery) 0.5 - 1.0 mL of 40 mg/mL nonbuffered gentamicin in three intratympanic instillations in 11 patients. Head impulse and caloric tests confirmed reduction of vestibular function in all patients. The control group consisted of 21 patients. Quality of life in both groups was evaluated using the Glasgow Benefit Inventory, the Glasgow Health Status Inventory and the Dizziness Handicap Inventory questionnaires. Visual symptoms and optokinetic sensation were evaluated using a specific questionnaire developed by our team and by measuring gains preoperatively and postoperatively in both groups using routine electronystagmography. The psychological profile was evaluated using the Zung Self-Rating Depression Scale and the Generalised Anxiety Disorder Assessment questionnaires.

RESULTS

There were no statistically significant differences between both groups with regards to the results of the questionnaires. Patients who received preoperative gentamicin were less sensitive to visual stimulation (P<0.10) and many of them had a significantly higher gain in the optokinetic nystagmus than the control group in the preoperative stage.

CONCLUSION

Pre-treatment with gentamicin helps to lower anxiety levels in patients and improves their general postoperative status. Pre-treated patients are also less sensitive to optokinetic stimulation.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03638310.

Benefits of pre-labyrinthectomy intratympanic gentamicin: contralateral vestibular responses

OBJECTIVE

To determine the impact of pre-operative intratympanic gentamicin injection on the recovery of patients undergoing translabyrinthine resection of vestibular schwannomas.

METHODS

This prospective, case-control pilot study included eight patients undergoing surgical labyrinthectomy, divided into two groups: four patients who received pre-operative intratympanic gentamicin and four patients who did not. The post-operative six-canal video head impulse test responses and length of in-patient stay were assessed.

RESULTS

The average length of stay was shorter for patients who received intratympanic gentamicin (6.75 days; range, 6-7 days) than for those who did not (9.5 days; range, 8-11 days) (p = 0.0073). Additionally, the gentamicin group had normal post-operative video head impulse test responses in the contralateral ear, while the non-gentamicin group did not.

CONCLUSION

Pre-operative intratympanic gentamicin improves the recovery following vestibular schwannoma resection, eliminating, as per the video head impulse test, the impact of labyrinthectomy on the contralateral labyrinth.

Different Visual Weighting due to Fast or Slow Vestibular Deafferentation: Before and after Schwannoma Surgery

Background

Feedback postural control depends upon information from somatosensation, vision, and the vestibular system that are weighted depending on their relative importance within the central nervous system. Following loss of any sensory component, the weighting changes, e.g., when suffering a vestibular loss, the most common notion is that patients become more dependent on visual cues for maintaining postural control. Dizziness and disequilibrium are common after surgery in schwannoma patients, which could be due to interpretation of the remaining sensory systems involved in feedback-dependent postural control and spatial orientation.

Objective

To compare visual dependency in spatial orientation and postural control in patients suffering from unilateral vestibular loss within different time frames.

Methods

Patients scheduled for schwannoma surgery: group 1 (n = 27) with no vestibular function prior to surgery (lost through years), group 2 (n = 12) with remaining vestibular function at the time of surgery (fast deafferentation), and group 3 (n = 18) with remaining function that was lost through gentamicin installations in the middle ear (slow deafferentation). All patients performed vibratory posturography and rod and frame investigation before surgery and 6 months after surgery.

Results

Postural control improved after surgery in patients that suffered a slow deafferentation (groups 1 and 3) (p < 0.001). Patients that suffered fast loss of remaining vestibular function (group 2) became less visual field dependent after surgery (p ≤ 0.035) and were less able to maintain stability compared with group 1 (p = 0.010) and group 3 (p = 0.010).

Conclusions

The nature and time course of vestibular deafferentation influence the weighting of remaining sensory systems in order to maintain postural control and spatial orientation.

Calibrating balance perturbation using electrical stimulation of the vestibular system

BACKGROUND

Supra-threshold galvanic vestibular stimulation (GVS) can be used to challenge the balance control system by disrupting vestibular inputs. The goal of this study was to propose an objective method to assess variability across subjects in the minimum safe GVS level that causes maximum balance degradation. New method: Thirteen healthy young subjects stood on a compliant foam surface with their eyes closed and tried to maintain a stable upright stance. Variables related to the stability of the trunk and whole body were quantified to characterize the relationship between postural responses and GVS at amplitudes from 0 to 4.5 mA in 0.5 mA increments. The relationship between decrements in postural responses and GVS was linear up to a minimum GVS level (called KNEE). An increase in the stimulation level above that did not lead to any further degradation of balance performance. The KNEE was determined by iteratively performing linear fits to the performance measure at different stimulation levels.

RESULTS

There were individual differences in KNEE; it was in the range of 1-2.5 mA across subjects. GVS caused an average performance decrement of 27-99% across six variables at the KNEE level compared to a no-stimulus condition. Comparison to existing methods: We propose a method to consistently attain the maximum level of impairment across subjects using the minimum current intensity, to minimize all types of adverse effects usually observed at high intensities.

CONCLUSIONS

Individual differences in the disruption of posture control in response to GVS have important implications for testing and training paradigms.

Vestibulo-Ocular Reflex Stabilization after Vestibular Schwannoma Surgery: A Story Told by Saccades

OBJECTIVE

To evaluate vestibular compensation via measurement of the vestibulo-ocular reflex (VOR) following vestibular schwannoma surgery and its relationship with changes in saccades strategy after surgery.

PATIENTS

Thirty-six consecutive patients with vestibular schwannomas, without brainstem compression, underwent surgical resection. Patients were recruited from University Hospital of Salamanca, Spain.

METHODS

We assessed the age, sex, tumor size, degree of canalicular weakness, and preoperative video head impulse test (gain and saccade organization measured with PR score). Gain and saccade organization were compared with postoperative values at discharge and also at 1, 3, and 6 months. PR scores are a measure of the scatter of refixation saccades.

RESULTS

Patients with normal preoperative caloric function had higher PR scores (saccades were scattered) following surgery compared to patients with significant preoperative canal paresis (p < 0.05). VOR gain and the presence of covert/overt saccades preoperatively did not influence the PR score (p > 0.05), but a group of patients with very low VOR gain (<0.45) and covert/overt saccades before surgery had lower PR scores after surgery. The differences after 6 months were not significant.

CONCLUSION

Patients with more severe vestibular dysfunction before vestibular schwannoma surgery show significantly faster vestibular compensation following surgery, manifested by changes in VOR gain and PR score. The scatter of compensatory saccades (as measured by the PR score) may be a surrogate early marker of clinical recovery, given its relationship to the Dizziness Handicap Inventory.

Vestibular Rehabilitation for Peripheral Vestibular Hypofunction: An Evidence-Based Clinical Practice Guideline: FROM THE AMERICAN PHYSICAL THERAPY ASSOCIATION NEUROLOGY SECTION

BACKGROUND

Uncompensated vestibular hypofunction results in postural instability, visual blurring with head movement, and subjective complaints of dizziness and/or imbalance. We sought to answer the question, "Is vestibular exercise effective at enhancing recovery of function in people with peripheral (unilateral or bilateral) vestibular hypofunction?"

METHODS

A systematic review of the literature was performed in 5 databases published after 1985 and 5 additional sources for relevant publications were searched. Article types included meta-analyses, systematic reviews, randomized controlled trials, cohort studies, case control series, and case series for human subjects, published in English. One hundred thirty-five articles were identified as relevant to this clinical practice guideline.

RESULTS/DISCUSSION

Based on strong evidence and a preponderance of benefit over harm, clinicians should offer vestibular rehabilitation to persons with unilateral and bilateral vestibular hypofunction with impairments and functional limitations related to the vestibular deficit. Based on strong evidence and a preponderance of harm over benefit, clinicians should not include voluntary saccadic or smooth-pursuit eye movements in isolation (ie, without head movement) as specific exercises for gaze stability. Based on moderate evidence, clinicians may offer specific exercise techniques to target identified impairments or functional limitations. Based on moderate evidence and in consideration of patient preference, clinicians may provide supervised vestibular rehabilitation. Based on expert opinion extrapolated from the evidence, clinicians may prescribe a minimum of 3 times per day for the performance of gaze stability exercises as 1 component of a home exercise program. Based on expert opinion extrapolated from the evidence (range of supervised visits: 2-38 weeks, mean = 10 weeks), clinicians may consider providing adequate supervised vestibular rehabilitation sessions for the patient to understand the goals of the program and how to manage and progress themselves independently. As a general guide, persons without significant comorbidities that affect mobility and with acute or subacute unilateral vestibular hypofunction may need once a week supervised sessions for 2 to 3 weeks; persons with chronic unilateral vestibular hypofunction may need once a week sessions for 4 to 6 weeks; and persons with bilateral vestibular hypofunction may need once a week sessions for 8 to 12 weeks. In addition to supervised sessions, patients are provided a daily home exercise program.

DISCLAIMER

These recommendations are intended as a guide for physical therapists and clinicians to optimize rehabilitation outcomes for persons with peripheral vestibular hypofunction undergoing vestibular rehabilitation.Video Abstract available for more insights from the author (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A124).

Vertigo Perception and Quality of Life in Patients after Surgical Treatment of Vestibular Schwannoma with Pretreatment Prehabituation by Chemical Vestibular Ablation

Surgical removal of vestibular schwannoma causes acute vestibular symptoms, including postoperative vertigo and oscillopsia due to nystagmus. In general, the dominant symptom postoperatively is vertigo. Preoperative chemical vestibular ablation can reduce vestibular symptoms postoperatively. We used 1.0 mL of 40 mg/mL nonbuffered gentamicin in three intratympanic installations over 2 days, 2 months preoperatively in 10 patients. Reduction of vestibular function was measured by the head impulse test and the caloric test. Reduction of vestibular function was found in all gentamicin patient groups. After gentamicin vestibular ablation, patients underwent home vestibular exercising for two months. The control group consisted of 10 patients who underwent only home vestibular training two months preoperatively. Postoperative rates of recovery and vertigo in both groups were evaluated with the Glasgow Benefit Inventory (GBI), the Glasgow Health Status Inventory (GHSI), and the Dizziness Handicap Inventory questionnaires, as well as survey of visual symptoms by specific questionnaire developed by us. There were no statistically significant differences between both groups with regard to the results of questionnaires. Patients who received preoperative gentamicin were more resilient to optokinetic and optic flow stimulation (p < 0.05). This trial is registered with clinical study registration number NCT02963896.

The Neurovestibular Challenges of Astronauts and Balance Patients: Some Past Countermeasures and Two Alternative Approaches to Elicitation, Assessment and Mitigation

Astronauts and vestibular patients face analogous challenges to orientation function due to adaptive exogenous (weightlessness-induced) or endogenous (pathology-induced) alterations in the processing of acceleration stimuli. Given some neurovestibular similarities between these challenges, both affected groups may benefit from shared research approaches and adaptation measurement/improvement strategies. This article reviews various past strategies and introduces two plausible ground-based approaches, the first of which is a method for eliciting and assessing vestibular adaptation-induced imbalance. Second, we review a strategy for mitigating imbalance associated with vestibular pathology and fostering readaptation. In discussing the first strategy (for imbalance assessment), we review a pilot study wherein imbalance was elicited (among healthy subjects) via an adaptive challenge that caused a temporary/reversible disruption. The surrogate vestibular deficit was caused by a brief period of movement-induced adaptation to an altered (rotating) gravitoinertial frame of reference. This elicited adaptation and caused imbalance when head movements were made after reentry into the normal (non-rotating) frame of reference. We also review a strategy for fall mitigation, viz., a prototype tactile sway feedback device for aiding balance/recovery after disruptions caused by vestibular pathology. We introduce the device and review a preliminary exploration of its effectiveness in aiding clinical balance rehabilitation (discussing the implications for healthy astronauts). Both strategies reviewed in this article represent cross-disciplinary research spin-offs: the ground-based vestibular challenge and tactile cueing display were derived from aeromedical research to benefit military aviators suffering from flight simulator-relevant aftereffects or inflight spatial disorientation, respectively. These strategies merit further evaluation using clinical and astronaut populations.

A Patient-Assessed Morbidity to Evaluate Outcome in Surgically Treated Vestibular Schwannomas

OBJECTIVE

Outcome after treatment of vestibular schwannomas can be evaluated by health providers as mortality, recurrence, performance, and morbidity. Because mortality and recurrence are rare events, evaluation has to focus on performance and morbidity. The latter has mostly been reported by health providers. In the present study, we validate 2 new scales for patient-assessed performance and morbidity in comparison with different outcome tools, such as quality of life (QOL) (European Quality of Life-5 dimensions [EQ-5D]), facial nerve score, and work capacity.

METHODS

There were 167 total patients in a retrospective (n = 90) and prospective (n = 50) cohort of surgically treated vestibular schwannomas. A new patient-assessed morbidity score (paMS), a patient-assessed Karnofsky score (paKPS), the patient-assessed QOL (EQ-5D) score, work capacity, and the House-Brackmann facial nerve score were used as outcome measures. Analysis of paMS components and their relation to other outcomes was done as uni- and multivariate analysis.

RESULTS

All outcome instruments, except EQ-5D and paKPS, showed a significant decrease postoperatively. Only the facial nerve score (House-Brackmann facial nerve score) differed significantly between the retrospective and prospective cohorts. Out of the 16 components of the paMS, hearing dysfunction, tear dysfunction, balance dysfunction, and eye irritation were most often reported. Both paMS and EQ-5D correlated significantly with work capacity.

CONCLUSIONS

Standard QOL and performance instruments may not be sufficiently sensitive or specific to measure outcome at the cohort level after surgical treatment of vestibular schwannomas. A morbidity score may yield more detailed information on symptoms that can be relevant for rehabilitation and occupational training after surgery.

Peripheral Vestibular System Disease in Vestibular Schwannomas: A Human Temporal Bone Study

INTRODUCTION

Dizziness is a common symptom in patients with vestibulo-cochlear schwannoma (VS), and several recent studies have identified this symptom as the single most important concerning the quality of life. Clinical and histological observations regarding hearing loss have suggested that this may be caused by both cochlear and retrocochlear mechanisms. Multiple mechanisms may also be at play in the case of dizziness, which may broaden perspectives of therapeutic approach. This study presents a systematic and detailed assessment of vestibular histopathology in temporal bones from patients with VS.

METHODS

Retrospective analysis of vestibular system histopathology in temporal bones from 17 patients with unilateral VS. The material was obtained from The Copenhagen Temporal Bone Collection.

RESULTS

Vestibular schwannomas were associated with atrophy of the vestibular ganglion, loss of fiber density of the peripheral vestibular nerve branches, and atrophy of the neuroepithelium of the vestibular end organs. In cases with small tumors, peripheral disease occurred only in the tissue structures innervated by the specific nerve from which the tumor originated.

CONCLUSION

Vestibular schwannomas are associated with distinctive disease of the peripheral vestibular tissue structures, suggesting anterograde degeneration and that dizziness in these patients may be caused by deficient peripheral vestibular nerve fibers, neurons, and end organs. In smaller tumors, a highly localized disease occurs, which opens perspectives of differentiated clinical assessment and subsequent, targeted therapy.

Current concepts and future approaches to vestibular rehabilitation

Over the last decades methods of vestibular rehabilitation to enhance adaptation to vestibular loss, habituation to changing sensory conditions, and sensory reweighting in the compensation process have been developed. However, the use of these techniques still depends to a large part on the educational background of the therapist. Individualized assessment of deficits and specific therapeutic programs for different disorders are sparse. Currently, vestibular rehabilitation is often used in an unspecific way in dizzy patients irrespective of the clinical findings. When predicting the future of vestibular rehabilitation, it is tempting to foretell advances in technology for assessment and treatment only, but the current intense exchange between clinicians and basic scientists also predicts advances in truly understanding the complex interactions between the peripheral senses and central adaptation mechanisms. More research is needed to develop reliable techniques to measure sensory dependence and to learn how this knowledge can be best used--by playing off the patient's sensory strength or working on the weakness. To be able using the emerging concepts, the neuro-otological community must strive to educate physicians, physiotherapists and nurses to perform the correct examinations for assessment of individual deficits and to look for factors that might impede rehabilitation.

[Rehabilitation of facial palsy and vertigo in patients with vestibular schwannoma]

BACKGROUND

Facial palsy and vertigo, as symptoms of vestibular schwannoma (VS) or consequences of its therapy, have a significant impact on patients' quality of life.

OBJECTIVE

This review analyzed current literature on the topic and deduced recommendations for rehabilitation of facial palsy and vertigo.

METHODS

The present review describes a PubMed-based search of the literature of the past 10 years.

RESULTS

There is no evidence-based drug therapy for the treatment of acute facial palsy after VS surgery. Several surgical procedures for facial nerve reconstruction, muscle transfer, and static techniques have been established. Physiotherapeutic movement therapy, optimally with biofeedback, seems to improve facial function in patients with post-paralytic syndrome. Botulinum toxin injections are the method of choice for synkinesis treatment. For treatment of acute and chronic vertigo in patients with VS, the same antivertiginous drugs as for other vertigo patients are used. If the patient shows retained vestibular stimulation function, preoperative intratympanic gentamycin therapy followed by compensation training is a promising approach to decreasing postoperative vertigo. Good vestibular rehabilitation comprises intensive and regular movement training, preferably with real-time feedback and therapy control.

CONCLUSION

There are several conservative, surgical, or combined conservative-surgical treatment options for individualized facial nerve rehabilitation of VS patients, as confirmed by clinical studies. In cases of acute vertigo, standard antivertiginous pharmacotherapy is indicated. In cases of acute and also of chronic vertigo, intensive balance and movement training relieves complaints.

Prediction of Balance Compensation After Vestibular Schwannoma Surgery

Background Balance compensation after vestibular schwannoma (VS) surgery is under the influence of specific preoperative patient and tumor characteristics. Objective To prospectively identify potential prognostic factors for balance recovery, we compared the respective influence of these preoperative characteristics on balance compensation after VS surgery. Methods In 50 patients scheduled for VS surgical ablation, we measured postural control before surgery (BS), 8 (AS8) days after, and 90 (AS90) days after surgery. Based on factors found previously in the literature, we evaluated age, body mass index and preoperative physical activity (PA), tumor grade, vestibular status, and preference for visual cues to control balance as potential prognostic factors using stepwise multiple regression models. Results An asymmetric vestibular function was the sole significant explanatory factor for impaired balance performance BS, whereas the preoperative PA alone significantly contributed to higher performance at AS8. An evaluation of patients' balance recovery over time showed that PA and vestibular status were the 2 significant predictive factors for short-term postural compensation (BS to AS8), whereas none of these preoperative factors was significantly predictive for medium-term postoperative postural recovery (AS8 to AS90). Conclusions We identified specific preoperative patient and vestibular function characteristics that may predict postoperative balance recovery after VS surgery. Better preoperative characterization of these factors in each patient could inform more personalized presurgical and postsurgical management, leading to a better, more rapid balance recovery, earlier return to normal daily activities and work, improved quality of life, and reduced medical and societal costs.

Chronic balance disorders after acoustic neuroma surgery: assessment of gravitational vertical perception

CONCLUSION

The head tilt response (HTR) test performed in a group of patients with chronic dizziness after acoustic neuroma surgery showed alterations in the gravitational vertical perception (GV).

OBJECTIVE

The assessment of the accuracy in the GV through the HTR test in patients with long-term balance disorders after acoustic neuroma surgery.

METHODS

The HTR was performed in two groups of patients that had undergone acoustic neuroma surgery: six uncompensated patients (UPs) who maintained vestibular symptoms 1 year after surgery and two compensated patients (CPs) without vestibular symptoms. Twelve healthy control adults were also tested (control group, CG). Three parameters were measured in the HTR test: steady-state error (SSE), rise time (TRS), and mean energy of the error signal per step (MEE).

RESULTS

The UP group showed higher values for the TRS and MEE parameters compared with the CG (p < 0.05) when performing the HTR test to the side of the lesion and to the contralateral side, while the SSE only showed significant higher values when the patient estimated the GV towards the side of the lesion. The two patients in the CP group did not have differences in the three parameters assessed when compared with the CG.

[Video head impulse test or caloric irrigation? Contemporary diagnostic tests for vestibular schwannoma]

The video head impulse test (vHIT) is a new method for investigating vestibular function that is currently poorly studied in terms of its value for clinical diagnosis in otolaryngology. Both the caloric irrigation and vHIT serve to evaluate the horizontal vestibulo-ocular reflex. In the present study, caloric irrigation and vHIT were compared in 46 patients with vestibular schwannoma. Caloric irrigation exhibits a higher sensitivity than vHIT (72% versus 41%) and both tests show only a moderate correlation. Tumor size and hearing level was significantly correlated with caloric abnormalities but not with vHIT findings. Since caloric irrigation and vHIT measure the hVOR in low and high frequency ranges, respectively, these tests have to be considered complementary and are valuable in both diagnostics and therapeutic decisions.

Surgery of the ear and the lateral skull base: pitfalls and complications

Surgery of the ear and the lateral skull base is a fascinating, yet challenging field in otorhinolaryngology. A thorough knowledge of the associated complications and pitfalls is indispensable for the surgeon, not only to provide the best possible care to his patients, but also to further improve his surgical skills. Following a summary about general aspects in pre-, intra-and postoperative care of patients with disorders of the ear/lateral skull base, this article covers the most common pitfalls and complications in stapes surgery, cochlear implantation and surgery of vestibular schwannomas and jugulotympanal paragangliomas. Based on these exemplary procedures, basic "dos and don'ts" of skull base surgery are explained, which the reader can easily transfer to other disorders. Special emphasis is laid on functional aspects, such as hearing, balance and facial nerve function. Furthermore, the topics of infection, bleeding, skull base defects, quality of life and indication for revision surgery are discussed. An open communication about complications and pitfalls in ear/lateral skull base surgery among surgeons is a prerequisite for the further advancement of this fascinating field in ENT surgery. This article is meant to be a contribution to this process.

The vestibulo-ocular reflex and subjective balance after vestibular schwannoma surgery

OBJECTIVES/HYPOTHESIS

To evaluate the vestibulo-ocular reflex and its relationship with subjective balance in a long-term follow-up after vestibular schwannoma surgery.

STUDY DESIGN

Retrospective cohorts study in a tertiary referral hospital. Forty-nine consecutive patients on which vestibular schwannoma surgery was performed at least 1 year before.

METHODS

Patients are classified in accordance with the morphology of the vestibulo-ocular reflex (VOR) into two groups: Group A, in which covert and overt saccades always occur in an organized fashion; and group B, in which covert and overt saccades randomly occur during head impulse and once finished. We evaluate the presence of covert and overt saccades and the morphology of the VOR measured by the video head impulse test (vHIT) and its relationship with subjective balance measured by Dizziness Handicap Inventory (DHI).

RESULTS

The group B patients returned a higher score in total DHI and all three subscales without any predominant subscale (P = 0,0002; t test). Group B patients were older than those in group A (P = 0,024; t test). No differences were found in sex distribution, tumor size, or side or time interval after surgery. Regarding the unaffected side, overt saccades were found to be more frequent in group B patients (P = 0.05; X(2)).

CONCLUSIONS

Long-term follow-up after vestibular schwannoma surgery has shown that 22% of the patients display a particular abnormality in the VOR because refixation saccades occur in a random fashion after elicitation of the reflex in the HIT test. These patients report the higher level of vestibular disability and handicap.

LEVEL OF EVIDENCE

2b.

Update on new medicinal applications of gentamicin: evidence-based review

Gentamicin (GM) was discovered in 1963 and was introduced into parenteral usage in 1971. Since then, GM has been widely used in medicinal applications. The Food and Drug Administration of the United States approved the routine prescription of GM to treat the following infectious disorders: infection due to Klebsiella pneumoniae, Escherichia coli, Serratia marcescens, Citrobacter spp., Enterobacteriaceae spp., Pseudomonas spp.; Staphylococcus infectious disease; bacterial meningitis; bacterial sepsis of newborns; bacterial septicemia; infection of the eye, bone, skin and/or subcutaneous tissue; infective endocarditis; peritoneal dialysis-associated peritonitis due to Pseudomonas and other gram-negative organisms; peritonitis due to gastrointestinal tract infections; respiratory tract infections; and urinary tract infectious disease. GM is an old antibiotic and is used widely beyond its FDA-labeled indications as follows: actinomycotic infection; Staphylococcus saprophyticus bacteremia with pyelonephritis; appendicitis; cystic fibrosis; diverticulitis; adjunct regimen for febrile neutropenia; female genital infection; uterine infection; postnatal infection; necrotizing enterocolitis in fetus or newborn; osteomyelitis; pelvic inflammatory disease; plague; gonorrhea; tularemia; prophylaxis of post-cholecystectomy infection, transrectal prostate biopsy, and post-tympanostomy-related infection; malignant otitis externa; and intratympanically or transtympanically for Ménière's disease. GM is also used in combination regimens, such as with beta-lactam antibiotics to treat mixed infection and with bacteriophage to treat Staphylococcus aureus infections. It is also added to medical materials, such as GM-loaded cement spacers for osteomyelitis and prosthetic joint-associated infections. Overall, there are many medicinal applications for GM. To reduce the development of GM-resistant bacteria and to maintain its effectiveness, GM should be used only to treat or prevent infections that are proven or strongly suspected as being caused by susceptible bacteria. In the future, we believe that GM will be used more widely in combination therapy and applied to medical materials for clinical applications. A definitive, appropriately powered study of this antibiotic and its clinical applications is now required, especially in terms of its effectiveness, safety, and cost.

How to uncover the covert saccade during the head impulse test

OBJECTIVE

The appearance of "covert" saccades in the head impulse test in patients with vestibular loss may lead to diagnostic misinterpretations. Here, we demonstrate a procedure that can convert covert eye saccades to overt when performing the head impulse test.

PATIENTS

Patients with known vestibular deficits that have covert saccades during head impulse test.

INTERVENTION

Diagnostic: random and sudden changes of the amplitude (degree of head turn) when performing the head impulse test.

MAIN OUTCOME MEASURE

Evaluation of bedside test with video recording and registration from video head impulse test (v-HIT).

RESULTS

A video recording and registration from v-HIT that demonstrate the covert saccades of a subject and how the overt saccade is uncovered by changing the amplitude of the head impulse. Five cases are briefly presented.

CONCLUSION

By performing the head impulse test with random amplitudes, overt saccades may become detectable and advance accuracy in bedside diagnosis of vestibular deficits.

Impact of pre-operative regular physical activity on balance control compensation after vestibular schwannoma surgery

Vestibular compensation after unilateral vestibular deafferentation is modulated by certain individual characteristics, such as pre-operative visual neurosensory preference or vestibular pattern. Physical activity (PA) allows the implementation of new sensorimotor and behavioral strategies leading to an improvement of balance control. This study aimed to evaluate the effect of the level of PA before surgery on balance compensatory mechanisms in patients after vestibular schwannoma (VS) surgery. Thirty patients with VS, 15 considered as regularly physically active and 15 as sedentary participated in this study, including an evaluation of gaze control by videonystagmography and postural control by a sensory organization test. Patients considered as physically active before surgery presented the best pattern of postural compensation, with the classical decrease in postural performances at short term (i.e. eight days) and the increase in postural performances at middle and long terms (i.e. 90 and 180 days, respectively) after surgery. For the sedentary patients, the consequences of surgery were more difficult to manage at short term, even though this did not prevent the ability to compensate well later on. Pre-operative practice of PA promotes the neuroplasticity of neural networks involved in motor learning, which allows to benefit of physical therapy more rapidly and efficiently.

Challenges and opportunities in managing the dizzy older adult

Balance disorders are common in elderly people, not only resulting in distressing sensations but also leading to reduced activity levels and quality of life. It has been estimated that 30% of elderly patients experience a balance disorder. Managing these disorders is a substantial challenge for patients and their caregivers and physicians. Moreover, abnormalities in balance are associated with falls, a major cause of morbidity and mortality for elderly people. Management is complicated by the inherent difficulties in assessing the generic complaint of dizziness, as well as the likelihood of multiple, often nonvestibular causes. The authors of this mini-seminar review both vestibular and nonvestibular causes of balance disorders in elderly people, emphasizing practical therapeutic maneuvers that can be used.

Vestibular rehabilitation of older adults with dizziness

The role of rehabilitation for treatment of older adults with dizziness and balance disorders is reviewed. Theories related to functional recovery from peripheral and central vestibular disorders are presented. Suggestions on which older adults might benefit from vestibular rehabilitation therapy are presented. Promising innovative rehabilitation strategies and technologies that might enhance recovery of the older adult with balance dysfunction are discussed.

Early vestibular physical therapy rehabilitation for Meniere's disease

Meniere disease includes symptoms of fluctuating hearing loss, tinnitus, and subjective ear fullness accompanied by episodic vertigo. Along with these symptoms, patients with chronic Meniere often develop symptoms of disequilibrium and unsteadiness that extend beyond the episodic attacks and contribute to the total disability and reduced quality of life attributed to the disease. Vestibular rehabilitation physical therapy has been used only after vestibular ablation has stabilized the vestibular loss, and for patients stably managed on medical therapy who exhibit no fluctuation in symptoms. This article reviews the data substantiating current applications of vestibular therapy, including improvements in subjective and objective balance outcome measures, and explores the possible extension of vestibular rehabilitation to treatment of patients exhibiting continued fluctuating vestibular loss.

Audiovestibular factors influencing quality of life in patients with conservatively managed sporadic vestibular schwannoma

OBJECTIVES

To measure the health-related quality of life (QoL) of patients undergoing conservative management of a vestibular schwannoma and to identify audiovestibular factors that influence health-related QoL.

STUDY DESIGN

Cross-sectional case-control study.

INTERVENTION

Adult patients undergoing conservative management of a sporadic vestibular schwannoma were identified from a prospectively updated database. Each patient was asked to complete a series of questionnaires, including the Short Form 36 health-related QoL instrument, the Hearing Handicap Inventory, the Tinnitus Handicap Inventory, and the Dizziness Handicap Inventory. The QoL data obtained were compared with UK normal data. Multiple linear regression was performed to identify audiovestibular factors influencing QoL.

PATIENTS

Of 241 patients still undergoing conservative management, 165 completed the questionnaires. The mean age was 66.6 years. Mean duration of follow-up was 5.7 years.

RESULTS

Physical component summary scores were significantly lower than those of the normal population. Mental component summary scores were significantly above the normal population. Regression analysis showed that dizziness handicap score and age were strong predictors of physical component summary (both p < 0.0001). Dizziness handicap score and tinnitus handicap score were significant predictors of mental component summary (p = 0.0004 and p = 0.027 respectively). However, the model only explained a small amount of the data, suggesting that there may be other factors influencing QoL.

CONCLUSION

Dizziness is the most significant audiovestibular predictor of QoL in patients with vestibular schwannomas. Tinnitus also has an impact on mental QoL. Hearing loss does not seem to influence QoL. Other factors such as illness perception may have an important role to play in determining QoL.

New methods for diagnosis and treatment of vestibular diseases

Dizziness and vertigo are common complaints, with a lifetime prevalence of over 30%. This review provides a brief summary of the recent diagnostic and therapeutic advances in the field of neuro-otology. A special focus is placed on the clinical usefulness of vestibular tests. While these have markedly improved over the years, treatment options for vestibular disorders still remain limited. Available therapies for selected vestibular diseases are discussed.