Signal Transparency of Remote Microphone Technology in Pediatric Bone Conduction Device Users

INTRODUCTION

Competing noise in the environment negatively affects speech intelligibility, particularly when listening at a distance. This is especially true for children with hearing loss in classroom environments where the signal-to-noise ratio is often poor. Remote microphone technology has been shown to be highly beneficial at improving the signal-to-noise ratio in hearing device users. Children with bone conduction devices, however, often must rely on indirect transmission of the acoustic signal for commonly used classroom-based remote microphone listening (e.g., digital adaptive microphone) which may negatively affect speech intelligibility. There are no studies on the effectiveness of using a relay method of signal delivery using remote microphone technology to improve speech intelligibility in adverse listening environments in bone conduction device users.

METHODS

Nine children with irresolvable conductive hearing loss and 12 adult controls with normal hearing were included for study. Controls were bilaterally plugged to simulate conductive hearing loss. All testing was conducted using the Cochlear™ Baha® 5 standard processor coupled with either the Cochlear™ Mini Microphone 2+ digital remote microphone or the Phonak Roger™ adaptive digital remote microphone. Speech intelligibility in noise was evaluated in the (1) bone conduction device processor alone, (2) bone conduction device + personal remote microphone, and (3) bone conduction device + personal remote microphone + adaptive digital remote microphone listening conditions at -10 dB, 0 dB, and +5 dB signal-to-noise ratios.

RESULTS AND CONCLUSIONS

Speech intelligibility in noise improved significantly in the bone conduction device + personal remote microphone condition over the bone conduction device alone, demonstrating significant benefit for listening at poor signal-to-noise ratios in children with conductive hearing loss using bone conduction devices with personal remote microphone use. Experimental findings demonstrate poor signal transparency when using the relay method. Coupling of the adaptive digital remote microphone technology to the personal remote microphone negatively affects signal transparency, and no hearing in noise improvements are observed. Significant gains in speech intelligibility are consistently observed for direct streaming methods and are confirmed in adult controls. Behavioral findings are supported by objective verification of the signal transparency between the remote microphone and the bone conduction device.

Guidelines for Best Practice in the Audiological Management of Adults Using Bimodal Hearing Configurations

Clinics are treating a growing number of patients with greater amounts of residual hearing. These patients often benefit from a bimodal hearing configuration in which acoustic input from a hearing aid on 1 ear is combined with electrical stimulation from a cochlear implant on the other ear. The current guidelines aim to review the literature and provide best practice recommendations for the evaluation and treatment of individuals with bilateral sensorineural hearing loss who may benefit from bimodal hearing configurations. Specifically, the guidelines review: benefits of bimodal listening, preoperative and postoperative cochlear implant evaluation and programming, bimodal hearing aid fitting, contralateral routing of signal considerations, bimodal treatment for tinnitus, and aural rehabilitation recommendations.

Effects of Bilateral Cochlear Implantation on Binaural Listening Tasks for Younger and Older Adults

PURPOSE

This study investigated the objective and subjective benefit of a second cochlear implant (CI) on binaural listening tasks of speech understanding in noise and localization in younger and older adults. We aimed to determine if the aging population can utilize binaural cues and obtain comparable benefits from bilateral CI (BIL_CI) when compared to the younger population.

METHODS

Twenty-nine adults with severe to profound bilateral sensorineural hearing loss were included. Participants were evaluated in two conditions, better CI (BE_CI) alone and BIL_CI using AzBio and Bamford-Kowal-Bench (BKB) sentence in noise tests. Localization tasks were completed in the BIL_CI condition using a broadband stimulus, low-frequency stimuli, and high-frequency stimuli. A subjective questionnaire was administered to assess satisfaction with CI.

RESULTS

Older age was significantly associated with poorer performance on AzBio +5 dB signal-to-noise ratio (SNR) and BKB-speech in noise (SIN); however, improvements from BE_CI to BIL_CI were observed across all ages. In the AzBio +5 condition, nearly half of all participants achieved a significant improvement from BE_CI to BIL_CI with the majority of those occurring in patients younger than 65 years of age. Conversely, the majority of participants who achieved a significant improvement in BKB-SIN were adults >65 years of age. Years of BIL_CI experience and time between implants were not associated with performance. For localization, mean absolute error increased with age for low and high narrowband noise, but not for the broadband noise. Response gain was negatively correlated with age for all localization stimuli. Neither BIL_CI listening experience nor time between implants significantly impacted localization ability. Subjectively, participants report reduction in disability with the addition of the second CI. There is no observed relationship between age or speech recognition score and satisfaction with BIL_CI.

CONCLUSION

Overall performance on binaural listening tasks was poorer in older adults than in younger adults. However, older adults were able to achieve significant benefit from the addition of a second CI, and performance on binaural tasks was not correlated with overall device satisfaction. The significance of the improvement was task and stimulus dependent but suggested a critical limit may exist for optimal performance on SIN tasks for CI users. Specifically, older adults require at least a +8 dB SNR to understand 50% of speech postoperatively; therefore, solely utilizing a fixed +5 dB SNR preoperatively to qualify CI candidates is not recommended as this test condition may introduce limitations in demonstrating CI benefit.

Instant improvement in monaural spatial hearing abilities through cognitive feedback

Several studies report that sound localization performance of acute and chronic monauralized normal-hearing listeners can improve through training. Typically, training sessions are administered daily for several days or weeks. While this intensive training is effective, it may also be that monaural localization abilities improve instantly after providing explicit top-down information about the direction dependent change in timbre and level. The aim of the present study was to investigate whether cognitive feedback (i.e., top-down information) could instantly improve sound localization in naive acutely monauralized listeners. Forty-three normal-hearing listeners (experimental group), divided over five different centers, were tested. Two control groups, consisting of, respectively, nine and eleven normal-hearing listeners, were tested in one center. Broadband sounds (0.5-20 kHz) were presented from visible loudspeakers, positioned in azimuth (- 90° to 90°). Participants in the experimental group received explicit information about the noticeable difference in timbre and the poor localization in the monauralized listening condition, resulting in an instant improvement in sound localization abilities. With subsequent roving of stimulus level (20 dB), sound localization performance deteriorated immediately. The reported improvement is related to the context of the localization test. The results provide important implications for studies investigating sound localization in a clinical setting, especially during closed-set testing, and indicate the importance of top-down information.

Portable eye-tracking as a reliable assessment of oculomotor, cognitive and reaction time function: Normative data for 18-45 year old

Eye movements measured by high precision eye-tracking technology represent a sensitive, objective, and non-invasive method to probe functional neural pathways. Oculomotor tests (e.g., saccades and smooth pursuit), tests that involve cognitive processing (e.g., antisaccade and predictive saccade), and reaction time tests have increasingly been showing utility in the diagnosis and monitoring of mild traumatic brain injury (mTBI) in research settings. Currently, the adoption of these tests into clinical practice is hampered by a lack of a normative data set. The goal of this study was to construct a normative database to be used as a reference for comparing patients' results. Oculomotor, cognitive, and reaction time tests were administered to male and female volunteers, aged 18-45, who were free of any neurological, vestibular disorders, or other head injuries. Tests were delivered using either a rotatory chair equipped with video-oculography goggles (VOG) or a portable virtual reality-like VOG goggle device with incorporated infrared eye-tracking technology. Statistical analysis revealed no effects of age on test metrics when participant data were divided into pediatric (i.e.,18-21 years, following FDA criteria) and adult (i.e., 21-45 years) groups. Gender (self-reported) had an effect on auditory reaction time, with males being faster than females. Pooled data were used to construct a normative database using 95% reference intervals (RI) with 90% confidence intervals on the upper and lower limits of the RI. The availability of these RIs readily allows clinicians to identify specific metrics that are deficient, therefore aiding in rapid triage, informing and monitoring treatment and/or rehabilitation protocols, and aiding in the return to duty/activity decision. This database is FDA cleared for use in clinical practice (K192186).

Bone Conduction: Benefits and Limitations of Surgical and Nonsurgical Devices

Bone conduction devices (BCDs) are a well-established and effective treatment solution for children with conductive and mixed hearing loss. Evidence indicates that early intervention through BCDs can improve hearing, speech, and language, and developmental outcomes. BCDs overcome several limitations associated with traditional hearing aids, and in many cases offer children an alternative to more invasive surgical management. Despite these benefits, children with conductive hearing loss are often subject to delays in intervention. In addition, interventional challenges and technological limitations of BCDs prevent widespread adoption and acceptance, particularly in early childhood.

Normative data for ages 18-45 for ocular motor and vestibular testing using eye tracking

OBJECTIVE

Eye tracking technology has been employed in assessing ocular motor and vestibular function following vestibular and neurologic conditions, including traumatic brain injury (TBI). Assessments include tests that provide visual and motion (rotation) stimuli while recording horizontal, vertical, and torsional eye movements. While some of these tests have shown diagnostic promise in previous studies, their use in clinical practice is limited by the lack of normative data. The goal of this study was to construct normative reference ranges to be used when comparing patients' results.

METHODS

Optokinetic response, subjective visual horizontal and vertical, and rotation tests were administered to male and female volunteers, ages 18-45, who were free from neurological, vestibular disorders, or other head injuries. Tests were administered using either a rotatory chair or a portable virtual reality-like goggle equipped with video-oculography.

RESULTS

Reference values for eye movements in response to different patterns of stimuli were analyzed from 290 to 449 participants. Analysis of gender (self-reported) or age when grouped as pediatric (late adolescent; 18-21 years of age) and adult (21-45 years of age) revealed no effects on the test metrics. Data were pooled and presented for each test metric as the 95% reference interval (RI) with 90% confidence intervals (CI) on upper and lower limits of the RI.

CONCLUSIONS

This normative database can serve as a tool to aid in diagnosis, treatment, and/or rehabilitation protocols for vestibular and neurological conditions, including mild TBI (mTBI). This database has been cleared by the FDA for use in clinical practice (K192186).

LEVEL OF EVIDENCE

2b.

Audiology Practices in the Preoperative Evaluation and Management of Adult Cochlear Implant Candidates

Importance

Currently, no clear guidelines exist regarding clinical testing methods for identifying adult cochlear implant (CI) candidates. Indications provided by the US Food and Drug Administration, Medicare, and private insurers are ambiguous concerning test materials and the level and mode of test presentation. This could lead to wide variability in clinical assessment and, potentially, unequal access to CIs for individuals with clinically significant hearing loss.

Objective

To examine the preoperative testing methods used by audiologists in evaluating adult CI candidates across the United States.

Design, Setting, and Participants

A survey assessing audiology practice patterns was created using a Research Electronic Data Capture system hosted at the University of Miami. A link to a survey (65 questions in multiple-choice or rank-order format was distributed electronically along with a request for completion to members of the American Cochlear Implant Alliance and to the Institute for Cochlear Implant Training forum. Responses were collected from January 17 to June 4, 2018. Participation was limited to audiologists who evaluate adult CI candidates, and respondents who do not provide adult CI care were excluded. Collected demographic information included work setting, years of experience, and highest level of education attained.

Main Outcomes and Measures

Percentages, medians, and interquartile ranges were from aggregated responses concerning hearing aid verification methods; testing methods, materials, and practices; nonauditory factors that might affect CI candidacy; audiology practice patterns; and expanded indications for CIs.

Results

Anonymized surveys were returned by 99 respondents; because surveys were available electronically, the number of audiologists who viewed the survey but did not respond was not available. Seven respondents identified themselves as pediatric specialists and were excluded, resulting in a total of 92 surveys available for analysis (denominators vary because respondents could complete the survey without answering all questions). Seventy percent of respondents (51 of 72) were doctors of audiology, and nearly 50% (33 of 74) were employed at universities and academic centers performing more than 50 CIs per year. When assessing adult candidacy for implant, most respondents reported using test materials from the Minimum Speech Test Battery: 96% (51 of 53), using AzBio sentences in quiet; 89% (47 of 53), AzBio sentences in noise; and 100% (53 of 53), the consonant-vowel nucleus-consonant, monosyllabic words test. However, these tests were applied inconsistently, with 39 of 53 respondents (74%) reporting use of a sound pressure level scale and the other 14 (26%) a hearing level scale at various decibel levels, and with some using a single signal-to-noise ratio and others using multiple ratios for sound-in-noise tests. Respondents' definitions of the best aided listening condition for assessing implant candidates also varied widely. Among the nonauditory factors ranked most important for assessing CI candidacy were patient's level of cognition and expectations of CI; yet, few respondents reported including cognitive or psychological tests in the assessment protocol.

Conclusions and Relevance

Findings of this study reveal considerable variability in preoperative testing methods and practices across health care professionals assessing adult candidates for CI. This lack of standardization in the delivery of care may increase the risk for health care inequities, specifically in access to care for adults with clinically significant hearing loss.

Comparisons of performance in pediatric bone conduction implant recipients using remote microphone technology

OBJECTIVES

For children with hearing loss, remote microphone (RM) technology can significantly improve access to speech in environments with poor signal-to-noise ratios (SNRs), such as classrooms. Yet, this has never been studied in bone conduction device (BCD) users, a common treatment for children with irresolvable conductive hearing loss resulting from anatomical malformations of the outer ear. The objective of this study was to investigate the benefits of RM technology on speech perception in noise in pediatric BCD users with Microtia/Atresia. A secondary aim was to assess parent and child perceptions of RM technology before and after exposure to RM technology.

METHODS

Participants included 10 pediatric bone conduction implant users with unilateral conductive hearing loss ages 7-17 years, and their guardians. Speech perception in noise for soft and moderate inputs was assessed with and without RM technology. Guardians actively observed the child's hearing performance with and without the RM and were asked to complete a questionnaire assessing their perceptions about their child's performance. Children were also administered the questionnaire prior to and immediately following exposure to the RM technology.

RESULTS

Participants showed improved speech understanding in noise for both soft and moderate speech inputs when using the RM with their BCD compared to their BCD alone. Questionnaire results indicated good parent-child agreement. Further, significant improvements were reported for child understanding speech, parent hearing domains after exposure to the RM. No significant differences were noted for ease of use/likability.

CONCLUSIONS

Significant hearing in noise benefits were observed with RM technology for children using BCDs. Consistent with objective findings, children reported improved speech understanding with the RM. Improved parental perceptions of hearing benefit following exposure to the RM suggests that active participation may serve as an effective strategy to help improve parent understanding of the benefits of RM technology for their child.

Oculomotor, vestibular, reaction time and cognitive eye-tracking mild traumatic brain injury assessment

Objective

Can oculomotor, vestibular, reaction time and cognitive eye-tracking tests (OVRT-C) assess mild traumatic brain injury?

Background

OVRT-C tests using eye tracking technology have been employed in our previous studies for assessing mild traumatic brain injury (mTBI). Here we present a composite Concussion Assessment algorithm that incorporates these findings.

Design/Methods

Concussion Assessment algorithm was based on a data analysis from 406 males and females 18–45 years old. The subjects included 106 patients diagnosed with mTBI and 300 healthy controls. Diagnosis of mTBI was made using accepted medical practice. The participants were tested with a battery of OVRT-C tests delivered on the I-Portal Neuro Otologic Test Center (Dx NOTC) device (Neurolign Technology). A logistic regression model was used to derive the algorithm using a random sample of 70% of the data-set and validated on the remaining 30% of the data-set. Device test-retest reliability and inter-rater variability were assessed in a separate study in healthy control volunteers, ages 19–43 (n = 30). Subjects were tested with OVRT-C tests using the Dx100 which is equivalent to the NOTC. Test-retest reliability was assessed using Intraclass Correlation Coefficient (ICC) and Cronbach's alpha; testers and devices influence were assessed using a random effect regression model.

Results

Test-retest reliability of OVRT-C tests using eye tracking technology was acceptable (ICC >0.6 for all variables). The Concussion assessment algorithm was based on six OVRT-C tests. In the validation data Concussion Assessment algorithm was able to separate concussed versus controls with a sensitivity of 78.6% and specificity of 72.3%.

Conclusions

OVRT-C tests delivered on I-Portal devices are repeatable and reliable. The assessment can identify mTBI subjects within an acute time post-injury with high sensitivity and specificity. The results support the use of this eye tracking device as well as the assessment to aid in the diagnosis of mTBI for patients 18–45 year old.

Nonsurgical Management of Single-Sided Deafness: Contralateral Routing of Signal

In recent years, an increasing research effort has been directed toward remediation of single-sided deafness. Contralateral routing of signal (CROS) is the longest standing rehabilitation solution for individuals with single-sided deafness. The primary goal of CROS technology is to transfer the signal received at the deaf ear to the better hearing ear, thereby reducing the impact of the acoustic head-shadow. This allows for individuals with single-sided deafness to regain access to sounds located at the deaf ear. The hearing deficits associated with single-sided deafness are often debilitating. While surgical management of single-sided deafness is on the rise, CROS hearing aids offer a nonsurgical option to compensate for some of the deficits that occur when a listener is limited to a single ear. Limitations of early CROS devices resulted in poor adoption and acceptance in those with single-sided deafness. Following significant advances in both design and technology, the acceptance of CROS devices has increased in recent years. This paper reviews relevant literature in CROS application for the management of single-sided deafness. Technological advances, benefits, limitations, and clinical considerations are also reviewed in this article.

Acute findings in an acquired neurosensory dysfunction

Background

In the Autumn of 2016, diplomatic personnel residing in Havana began to present with symptoms of dizziness, ear pain, and tinnitus that emerged after perception of high frequency noise and/or a pressure sensation. Understanding the acute symptoms of this disorder is important for better defining the disorder and developing optimal diagnostic, preventive, and treatment algorithms.

Objectives

To define the presenting symptoms in a cohort of patients in the acute time period after perceiving a noise/pressure exposure in Havana.

Design/Settings/Participants

Review of 25 symptomatic individuals who reported a localized sensation of noise/pressure and 10 asymptomatic individuals (roommates of those affected) who did not experience the sound/pressure.

Results

Immediately after the exposure, the majority of individuals reported intense ear pain in one or both ears and experienced tinnitus. All of the individuals noticed unsteadiness and features of cognitive impairment. On presentation to our center, dizziness (92%) and cognitive complaints (56%) were the most common symptoms. Formal testing revealed that 100% of individuals had an otolithic abnormality and evidence of cognitive dysfunction.

Conclusion and Relevance

This study focuses on the acute presentation of a phenomenon in which symptoms emerge after perception of a localized noise/pressure and in which the acute symptomology includes the universal nature of vestibular injuries and select cognitive deficits. The findings presented in this acute group of patients begin to provide a better picture of the initial injury pattern seen after this exposure and may allow for more accurate diagnosis of this disorder in future cases.

Level of Evidence

Retrospective review

Evaluation of multisensory responses (oculomotor, vestibular, and reaction time) in 3, 8 and 15 days after mild traumatic brain injury

Background

Despite the prevalence of mild traumatic brain injury (mTBI, concussion) in a wide range of occupational, sport, and military settings, accurate diagnosis and optimal treatment of concussive injuries are delayed by several challenging obstacles. Ability to measure the multisensory functional integrity of numerous neuroanatomical pathways with multiple tasks (oculomotor, vestibular and reaction time) can capture impairments of brain function.

Methods

106 mTBI patients and 300 control subjects were tested in the vestibular labs at 2 military hospitals. Patients were tested 3 times at average 2.5, 8.5 and 15.8 days post-injury. All patients completed a health history questionnaire, a dizziness handicap index (DHI), a functional gait index (FGI), and Trail Making Tests (TMTs) and were assessed by a battery of tests with video-oculography (I-Portal VOG) comprised of a head mounted, high speed eye tracking system on a rotary chair device (I-Portal Neuro-Otologic Test Center). The individuals in the study performed multiple tests including saccades, antisaccade, pursuit tracking, nystagmus, optokinetic, vestibular motion, and reaction time.

Results

No single test was sufficiently predictive to have separation between controls and mTBI subjects but results from a computer controlled rotational head impulse test (crHIT), antisaccade and predictive saccade were highly correlated with mTBI for the first test session. Longitudinally, for example, 74% of patients in session 1, 56% in session 2% and 51% in session 3 had in crHIT gain or absolute asymmetry above 95% of the respective control's distribution.

Conclusion

These results suggest that vestibular, oculomotor and reaction time tests using can provide an objective and reliable method of capturing and quantifying abnormal response in patients with mTBI. In addition, this type of testing can be used to monitor the recovery process.

The use of oculomotor, vestibular, and reaction time tests to assess mild traumatic brain injury (mTBI) over time

Objectives

The objective of this work is to examine the outcomes of a set of objective measures for evaluating individuals with minor traumatic brain injury (mTBI) over the sub‐acute time period. These methods involve tests of oculomotor, vestibular, and reaction time functions. This work expands upon published work examining these test results at the time of presentation.

Study Design

This study is a prospective age‐ and sex‐matched controlled study.

Materials and Methods

The subject group was composed of 106 individuals with mTBI and 300 age‐ and sex‐matched controls without a history of mTBI. All individuals agreeing to participate in the study underwent a battery of oculomotor, vestibular, and reaction time tests (OVRT). Those subjects with mTBI underwent these tests at presentation (within 6 days of injury) and 1 and 2weeks post injury. These outcomes were compared to each other over time as well as to results from the controls that underwent 1 test session.

Results

Six measures from 5 tests can classify the control and mTBI during Session 1 with a true positive rate (sensitivity) of 84.9% and true negative rate (specificity) of 97.0%. Patterns of abnormalities changed over time in the mTBI group and overall normalized in a subset of individuals at the third (final) testing session.

Conclusions

We describe an objective and effective second generation testing algorithm for diagnosing and following the prognosis of mTBI/concussion. This testing paradigm will allow investigators to institute better treatments and provide more accurate return to activity advice.

Level of Evidence

3

Oculomotor, Vestibular, and Reaction Time Tests in Mild Traumatic Brain Injury

Objective

Mild traumatic brain injury is a major public health issue and is a particular concern in sports. One of the most difficult issues with respect to mild traumatic brain injury involves the diagnosis of the disorder. Typically, diagnosis is made by a constellation of physical exam findings. However, in order to best manage mild traumatic brain injury, it is critically important to develop objective tests that substantiate the diagnosis. With objective tests the disorder can be better characterized, more accurately diagnosed, and studied more effectively. In addition, prevention and treatments can be applied where necessary.

Methods

Two cohorts each of fifty subjects with mild traumatic brain injury and one hundred controls were evaluated with a battery of oculomotor, vestibular and reaction time related tests applied to a population of individuals with mild traumatic brain injury as compared to controls.

Results

We demonstrated pattern differences between the two groups and showed how three of these tests yield an 89% sensitivity and 95% specificity for confirming a current diagnosis of mild traumatic brain injury.

Interpretation

These results help better characterize the oculomotor, vestibular, and reaction time differences between those the mild traumatic brain injury and non-affected individuals. This characterization will allow for the development of more effective point of care neurologic diagnostic techniques and allow for more targeted treatment which may allow for quicker return to normal activity.

Utricular paresis and semicircular canal hyperactivity: a distinct otolith syndrome

CONCLUSIONS

Although combined utricular and canal paresis has been described previously, this is the first report of canal hyperactivity associated with utricular hypofunction. Unsteadiness and swaying were the most common symptoms, and patients with shorter duration of symptoms also had positional vertigo. We propose that this syndrome is a variant of utricular dysfunction and should be considered in the differential diagnosis of peripheral vestibular disorders.

OBJECTIVE

To describe a syndrome of instability associated with utricular dysfunction and hyperactive caloric responses.

METHODS

The study comprised 11 consecutive patients exhibiting abnormalities of the eccentric subjective visual vertical test (e-SVV) and high responses during the caloric test of the videonystagmography (VNG). We carried out a review of symptoms, physical examination, and vestibular tests.

RESULTS

There was no gender predilection or obvious etiology. The patients' main complaint included instability with linear symptoms (i.e., tilting, rocking, and swaying), with positional vertigo as a secondary symptom. Oculomotor testing, visual fixation index, and brain MRI were normal, excluding a central nervous system disorder. VNG was essentially normal except for hyperactive responses during the caloric testing in all patients. Abnormal e-SVV was found in 10 patients unilaterally and bilaterally in 1 patient. Abnormal oVEMP was found in seven of seven patients, further supporting a utricular site of lesion.

Utricular Dysfunction in Refractory Benign Paroxysmal Positional Vertigo

Objective

To determine the prevalence of otolith dysfunction in patients with refractory benign paroxysmal positional vertigo (BPPV).

Study Design

Unmatched case control.

Setting

Tertiary care institution.

Subjects and Methods

Patients included were diagnosed with BPPV, failed initial in-office canalith repositioning maneuvers (CRMs), and completed vestibular testing and vestibular rehabilitation (n = 40). Refractory BPPV (n = 19) was defined in patients whose symptoms did not resolve despite vestibular rehabilitation. These patients were compared with a control group of those with nonrefractory BPPV (n = 21) for results of a caloric test, cervical vestibular evoked myogenic potential (cVEMP), and subjective visual vertical (SVV).

Results

Forty-six of 251 patients failed initial treatment with in-office CRM. Forty patients met inclusion criteria. There was no significant difference between the cases (refractory BPPV) (n = 19) and controls (nonrefractory BPPV) (n = 21) in terms of age, duration of symptoms, laterality of BPPV, and BPPV symptoms. There was no difference in the prevalence of caloric weakness and cVEMP abnormalities ( P > .05), with odds ratios (ORs [95% confidence interval (CI)]) of having abnormal results among cases vs controls of 1.1818 (0.3329-4.1954) and 4.3846 (0.7627-25.2048), for caloric and cVEMP, respectively. Abnormal eccentric SVV was more prevalent in refractory BPPV cases (58%) than in controls (14%) ( P < .0072). The OR (95% CI) of having abnormal SVV was 8.25 (1.7967-37.8822) higher among patients with refractory BPPV than those with nonrefractory BPPV.

Conclusion

Patients with refractory BPPV are more likely to have abnormal eccentric SVV and thus underlying utricular dysfunction. This finding is important to take into account when designing rehabilitation strategies for patients with BPPV who fail CRM.

Head-shaking nystagmus predicts greater disability in unilateral peripheral vestibulopathy

OBJECTIVES

The objective of this study was to determine the association of the bedside test of head-shaking nystagmus (HSN) with patients' self-perceived dizziness handicap as well as this test's sensitivity and specificity in unilateral peripheral vestibular hypofunction.

STUDY DESIGN

A retrospective case-control study was performed.

SETTING

The study was held at an academic, tertiary referral center.

METHODS

Fifty-three adult patients with unilateral peripheral hypofunction defined by the caloric test of the videonystagmography with documented bedside HSN and who had completed questionnaires of self-perceived dizziness handicap were included. The sensitivity and specificity of the bedside HSN in patients and 10 healthy controls in diagnosing unilateral vestibular hypofunction defined by videonystagmographic caloric testing and by abnormal gain and symmetry of the vestibular-ocular reflex by rotary chair testing were determined. Scores of the screening test of the Dizziness Handicap Index and Functional Level Scale questionnaires were taken.

RESULTS

When using the caloric irrigation test as the reference standard for unilateral vestibular hypofunction, the sensitivity, specificity, and positive predictive value of the bedside HSN were 31%, 96%, and 97%, respectively. When comparing with results of rotational chair testing (vestibular-ocular reflex gain and symmetry), the sensitivity of the HSN test increases to 71%. Patients with positive bedside HSN had higher scores (greater self-perceived dizziness handicap) of the Dizziness Handicap Index (P = .049) and higher (worse) scores of the Functional Level Scale (P = .0377) than those with negative bedside HSN (Wilcoxon rank test).

CONCLUSIONS

Greater perceived handicap was correlated with a positive bedside HSN in patients with unilateral peripheral vestibulopathy. The HSN has sufficient sensitivity to be used as screening test of uncompensated vestibulopathy in this series. However, a negative HSN alone does not rule out the diagnosis of peripheral vestibular dysfunction.