Electrocochleography in Cochlear Implant Recipients: Correlating Maximum Response With Residual Hearing.

OBJECTIVES: Electrocochleography (ECochG) is increasingly recognized as a biomarker for assessing inner ear function in cochlear implant patients. This study aimed to objectively determine intraoperative cochlear microphonic (CM) amplitude patterns and correlate them with residual hearing in cochlear implant recipients, addressing the limitations in current ECochG analysis that often depends on subjective visual assessment and overlook the intracochlear measurement location. DESIGN: In this prospective study, we investigated intraoperative pure-tone ECochG following complete electrode insertion in 31 patients. We used our previously published objective analysis method to determine the maximum CM amplitude and the associated electrode position for each electrode array. Using computed tomography, we identified electrode placement and determined the corresponding tonotopic frequency using Greenwood's function. Based on this, we calculated the tonotopic shift, that is, the difference between the stimulation frequency and the estimated frequency of the electrode with the maximum CM amplitude. We evaluated the association between CM amplitude, tonotopic shift, and preoperative hearing thresholds using linear regression analysis. RESULTS: CM amplitudes showed high variance, with values ranging from -1.479 to 4.495 dBµV. We found a statistically significant negative correlation () between maximum CM amplitudes and preoperative hearing thresholds. In addition, a significant association () between the tonotopic shift and preoperative hearing thresholds was observed. Tonotopic shifts of the maximum CM amplitudes occurred predominantly toward the basal direction. CONCLUSIONS: The combination of objective signal analysis and the consideration of intracochlear measurement locations enhances the understanding of cochlear health and overcomes the obstacles of current ECochG analysis. We could show the link between intraoperative CM amplitudes, their spatial distributions, and preoperative hearing thresholds. Consequently, our findings enable automated analysis and bear the potential to enhance specificity of ECochG, reinforcing its role as an objective biomarker for cochlear health.

Prevention of nostril lacerations in endonasal drilling procedures by use of a conventional protective ear speculum.

PURPOSE: Injuries of the nasal vestibular skin caused by the rotating burr shafts can represent a tedious complication following endonasal drilling and is experienced sooner or later by every rhino-surgeon. MATERIAL AND METHODS: To protect the nasal entrance from laceration by the free rotating drill shaft we position an otology speculum in the nasal entrance. The speculum is held in place by the scrub nurse during the critical phase of bone drilling. RESULTS: Following the introduction of the ear speculum protection, we successfully treated our dacryocystostamia procedures (n = 27) and median maxillectomia procedures (n = 6) without any further soft tissue erosions. DISCUSSION: Preventive measures for injuries by endonasal drilling procedures are not reported extensively in literature. This stands in contrast to the fact that these injuries are prone to cause significant suffering as amply described in the case of nostril laceration due to nasogastric intubation or nasogastric feeding tubes. CONCLUSION: The use of a readily available, reusable ear speculum in endonasal drill application eliminated the complication of nasal entrance lacerations throughout our institution, hitherto.

Impact of COVID-19 pandemic: increase in complicated upper respiratory tract infections requiring ENT surgery?

PURPOSE: This study investigates the impact of the COVID-19 pandemic on complicated upper respiratory tract infections requiring surgical intervention in a tertiary referral center. The aim is to understand the consequences of pandemic-related measures and their subsequent relaxation on the incidence and characteristics of upper respiratory tract infection-related complications. METHODS: Patients who underwent surgery as a complication of upper respiratory tract infections between December 2014 to February 2023 were included. Demographic information, surgical procedures, microbiological findings, and clinical outcomes were assessed and analyzed comparing pre-pandemic, pandemic and post-pandemic groups. RESULTS: 321 patients were enrolled, including 105 patients (32.7%) in the pediatric population. Comparison of pre-pandemic (n = 210), pandemic (n = 46) and post-pandemic periods (n = 65) revealed a statistically significant increase in complicated otologic infections requiring surgical intervention in the post-pandemic period compared to the pandemic period (p value = 0.03). No statistically significant differences in other surgical procedures or demographic parameters were observed. A statistically significant increase in urgent ear surgery in the pediatric population between the pandemic and the post-pandemic period (p value = 0.02) was observed. Beta-hemolytic group A streptococcal infections showed a statistically significant increase in the post-pandemic period compared with the pandemic period (p value = 0.02). CONCLUSIONS: Relaxation of COVID-19-related restrictions was associated with an increase of upper respiratory tract infection-related otologic infections requiring surgical intervention with an increasing rate of beta-hemolytic group A streptococcal infections. These findings highlight the importance of considering the impact of the pandemic on upper respiratory tract infection complications and adapting management strategies accordingly.

The acute vestibular syndrome: prevalence of new hearing loss and its diagnostic value.

OBJECTIVES: To assess the prevalence of new hearing losses in patients with acute vestibular syndrome (AVS) and to start to evaluate its diagnostic value for the differentiation between peripheral and central causes. DESIGN: We performed a cross-sectional prospective study in AVS patients presenting to our Emergency Department (ED) from February 2015 to November 2020. All patients received an MRI, Head-impulse test, Nystagmus test and Test of skew ('HINTS'), caloric testing and a pure-tone audiometry. RESULTS: We assessed 71 AVS patients, 17 of whom had a central and 54 a peripheral cause of dizziness. 12.7% had an objective hearing loss. 'HINTS' had an accuracy of 78.9% to diagnose stroke, whereas 'HINTS' plus audiometry 73.2%. 'HINTS' sensitivity was 82.4% and specificity 77.8% compared to 'HINTS' plus audiometry showing a sensitivity of 82.4% and specificity of 70.4%. The four patients with stroke and minor stroke had all central 'HINTS'. 55% of the patients did not perceive their new unilateral hearing loss. CONCLUSIONS: We found that almost one-eighth of the AVS patients had a new onset of hearing loss and only half had self-reported it. 'HINTS' plus audiometry proved to be less accurate to diagnose a central cause than 'HINTS' alone. Audiometry offered little diagnostic accuracy to detect strokes in the ED but might be useful to objectify a new hearing loss that was underestimated in the acute phase. Complete hearing loss should be considered a red flag, as three in four patients suffered from a central cause.

To detach or not to detach the umbo in type I tympanoplasty: functional results.

PURPOSE: To compare the audiological outcomes, tympanic membrane (TM) healing rates and complication rates in patients undergoing endoscopic underlay and over-under tympanoplasty type I (TTI). METHODS: The study includes 95 patients who underwent endoscopic TTI in the period between 2018 and 2023: 56% of the patients had the underlay technique and 41% had the over-under technique. Data regarding pre- and postoperative hearing, perforation characteristics, surgical procedures, graft types and complications were retrospectively analyzed. Audiometrical assessment included air conduction (AC) and bone conduction (BC) pure tone averages (PTA) and air-bone gap (ABG), pre- and postoperatively. RESULTS: Both underlay and over-under techniques significant improved AC PTA, with a mean ABG improvements of 5.9 dB and 7.2 dB, respectively. There was no significant difference in BC PTA between pre- and post-operative, indicating no inner ear damage in both techniques. The over-under technique showed a significantly higher TM closure rate (94.4%) compared to the underlay technique (80.6%). Complications were rare, with only one case of TM lateralization requiring revision surgery. CONCLUSIONS: Endoscopic TTI is an effective treatment in improving auditory function in chronic middle ear diseases. In our cohort, the detachment of the umbo does not negatively influence the postoperative hearing results and does not increase rate of complications. Moreover, the over-under technique demonstrates superior TM closure rates, making it a valuable option for specific cases. However, future prospective studies with larger sample sizes and longer term follow-up are needed to validate these findings and provide more comprehensive insights.

Postoperative Impedance-Based Estimation of Cochlear Implant Electrode Insertion Depth.

OBJECTIVES: Reliable determination of cochlear implant electrode positions shows promise for clinical applications, including anatomy-based fitting of audio processors or monitoring of electrode migration during follow-up. Currently, electrode positioning is measured using radiography. The primary objective of this study is to extend and validate an impedance-based method for estimating electrode insertion depths, which could serve as a radiation-free and cost-effective alternative to radiography. The secondary objective is to evaluate the reliability of the estimation method in the postoperative follow-up over several months. DESIGN: The ground truth insertion depths were measured from postoperative computed tomography scans obtained from the records of 56 cases with an identical lateral wall electrode array. For each of these cases, impedance telemetry records were retrieved starting from the day of implantation up to a maximum observation period of 60 mo. Based on these recordings, the linear and angular electrode insertion depths were estimated using a phenomenological model. The estimates obtained were compared with the ground truth values to calculate the accuracy of the model. RESULTS: Analysis of the long-term recordings using a linear mixed-effects model showed that postoperative tissue resistances remained stable throughout the follow-up period, except for the two most basal electrodes, which increased significantly over time (electrode 11: ~10 Ω/year, electrode 12: ~30 Ω/year). Inferred phenomenological models from early and late impedance telemetry recordings were not different. The insertion depth of all electrodes was estimated with an absolute error of 0.9 mm ± 0.6 mm or 22° ± 18° angle (mean ± SD). CONCLUSIONS: Insertion depth estimations of the model were reliable over time when comparing two postoperative computed tomography scans of the same ear. Our results confirm that the impedance-based position estimation method can be applied to postoperative impedance telemetry recordings. Future work needs to address extracochlear electrode detection to increase the performance of the method.

Clinical impact of manual scoring of peripheral arterial tonometry in patients with sleep apnea.

PURPOSE: The objective was to analyze the clinical implications of manual scoring of sleep studies using peripheral arterial tonometry (PAT) and to compare the manual and automated scoring algorithms. METHODS: Patients with suspected sleep-disordered breathing underwent sleep studies using PAT. The recordings were analyzed using a validated automated computer-based scoring and a novel manual scoring algorithm. The two methods were compared regarding sleep stages and respiratory events. RESULTS: Recordings of 130 patients were compared. The sleep stages and time were not significantly different between the scoring methods. PAT-derived apnea-hypopnea index (pAHI) was on average 8.4 events/h lower in the manually scored data (27.5±17.4/h vs.19.1±15.2/h, p<0.001). The OSA severity classification decreased in 66 (51%) of 130 recordings. A similar effect was found for the PAT-derived respiratory disturbance index with a reduction from 31.2±16.5/h to 21.7±14.4/h (p<0.001), for automated and manual scoring, respectively. A lower pAHI for manual scoring was found in all body positions and sleep stages and was independent of gender and body mass index. The absolute difference of pAHI increased with sleep apnea severity, while the relative difference decreased. Pearson's correlation coefficient between pAHI and oxygen desaturation index (ODI) significantly improved from 0.89 to 0.94 with manual scoring (p<0.001). CONCLUSIONS: Manual scoring results in a lower pAHI while improving the correlation to ODI. With manual scoring, the OSA category decreases in a clinically relevant proportion of patients. Sleep stages and time do not change significantly with manual scoring. In the authors' opinion, manual oversight is recommended if clinical decisions are likely to change.

Performance with a new bone conduction implant audio processor in patients with single-sided deafness.

PURPOSE: The SAMBA 2 BB audio processor for the BONEBRIDGE bone conduction implant features a new automatic listening environment detection to focus on target speech and to reduce interfering speech and background noises. The aim of this study was to evaluate the audiological benefit of the SAMBA 2 BB (AP2) and to compare it with its predecessor SAMBA BB (AP1). METHODS: Prospective within-subject comparison study. We compared the aided sound field hearing thresholds, speech understanding in quiet (Freiburg monosyllables), and speech understanding in noise (Oldenburg sentence test) with the AP1 and AP2. Each audio processor was worn for 2 weeks before assessment and seven users with single-sided sensorineural deafness (SSD) participated in the study. For speech understanding in noise, two complex noise scenarios with multiple noise sources including single talker interfering speech were used. The first scenario included speech presented from the front (S0NMIX), while in the second scenario speech was presented from the side of the implanted ear (SIPSINMIX). In addition, subjective evaluation using the SSQ12, APSQ, and the BBSS questionnaires was performed. RESULTS: We found improved speech understanding in quiet with the AP2 compared to the AP1 aided condition (on average + 17%, p = 0.007). In both noise scenarios, the AP2 lead to improved speech reception thresholds by 1.2 dB (S0NMIX, p = 0.032) and 2.1 dB (SIPSINMIX, p = 0.048) compared to the AP1. The questionnaires revealed no statistically significant differences, except an improved APSQ usability score with the AP2. CONCLUSION: Clinicians can expect that patients with SSD will benefit from the SAMBA 2 BB by improved speech understanding in both quiet and in complex noise scenarios, when compared to the older SAMBA BB.

Variability of the retrotympanum and its association with mastoid pneumatization in cholesteatoma patients.

PURPOSE: This study aimed to investigate the variability of the retrotympanum in patients undergoing surgical treatment for cholesteatoma. METHODS: We included 59 ears of patients undergoing middle ear surgery for cholesteatoma who had preoperative computed tomography scans. A retrospective analysis of the medical records was conducted. The sinus tympani (ST), subtympanic sinus (STS) and facial recess (FR) were classified into types A-C based on the relationship of their extension to the facial nerve. The mastoid and petrous apex were assessed and categorized as normal pneumatized or sclerotic. RESULTS: Type A extension was the most frequently found in all sinuses (ST 64%, FR 77%, STS 69%), Type B extension was found more often in ST (34%) and STS (24%) than in FR (15%). A very deep extension was found only rarely (ST 2%, FR 8%, STS 7%). A sclerotic mastoid was found in 67% of cases. Those cases showed a statistically significant difference regarding retrotympanum pneumatization when compared with normal mastoid. CONCLUSION: The most frequent variant of retrotympanic pneumatization in relation to the facial nerve was type A in all subsites in cholesteatoma patients. The variability among patients with cholesteatoma is different to previously published results in healthy subjects. Moreover, the pneumatization of the retrotympanum is associated with mastoid pneumatization.

Taste Alteration in External Auditory Canal Cholesteatoma: Indicator of Impending N VII Affection.

INTRODUCTION: External auditory canal cholesteatoma (EACC) is a rare disease, with an estimated incidence of approximately 1:1,000 adult and 1.6:1,000 pediatric otologic patients. Systematic studies of chronic ear disease and taste alteration prior to surgery are rare; in fact, there are no such studies for EACCs. Therefore, we describe chorda tympani nerve (CTN) dysfunction and the related clinical consequences in EACC patients. METHODS/STUDY DESIGN: Between 1992 and 2021, we retrospectively analyzed the symptoms, signs, and radiological and intraoperative descriptions of CTN involvement in 73 patients. Liquid taste tests and, since 2009, Taste StripsTM as well as an olfactory screening test (Smell DiskettesTM) have been performed for all symptomatic patients and, when feasible, all other EACC patients. RESULTS: Ten of 73 patients complained subjectively of dysfunction, and 8 showed abnormal taste test results. Four patients complained of olfactory dysfunction (3 cases with pathological taste tests). Gustatory dysfunction was most frequent in radiogenic EACC cases (n = 4), followed by postoperative EACC (n = 3). Two postoperative patients were asymptomatic despite abnormal test results. Rarely, patients with idiopathic (n = 2) and posttraumatic (n = 1) EACC showed acute taste dysfunction that was confirmed in each with abnormal test results. DISCUSSION/CONCLUSION: CTN dysfunction often developed asymptomatically in chronic ears, except for idiopathic and posttraumatic EACCs under previous healthy middle ear conditions. Taste disturbance is not a cardinal symptom of EACC, but objective testing suggests that up to one out of 10 EACC patients with advanced disease may experience regional gustatory dysfunction prior to surgery. Especially in context of a new and acute presentation, regional taste dysfunction may alert the clinician of potential progressive EACC invasion and danger to the facial nerve.

Digital image enhancement may improve sensitivity of cholesteatoma detection during endoscopic ear surgery.

OBJECTIVES: This study investigates the possible benefits and limitations of the digital image enhancement systems provided by Storz Professional Image Enhancement System (SPIES) during endoscopic ear surgery (EES) for cholesteatoma. An increased detection of cholesteatoma residuals during the final steps of endoscopic surgery using DIE technology was hypothesized. DESIGN: Cross-sectional study. SETTING: Tertiary referral hospital. METHODS: A total of 10 questionnaires of 18 intraoperative pictures with equal numbers of cholesteatoma and non-cholesteatoma images, each presented in three different image-enhancing modalities (Clara, Spectra A, Spectra B), were generated. Fifty-one experienced ear surgeons participated to the survey and were randomly assigned to a questionnaire and completed it at two time points. The experts were asked to rate for each picture whether cholesteatoma was present or not. The answers were compared with the histopathological reports. RESULTS: Clara showed the highest accuracy in cholesteatoma detection, followed by Spectra A and lastly Spectra B. In contrast, Spectra B showed the highest sensitivity and Clara the highest specificity, while Spectra A was placed in the middle for both values. Using the Spectra B modality, most responses agreed across the two time points. Ear surgeons assessed the usefulness, as well as preference among image modalities for cholesteatoma surgery, in the following order: Clara, Spectra B, Spectra A. CONCLUSION: Digital enhancement technologies are applicable to EES. After complete cholesteatoma removal, Spectra B showed the highest sensitivity in the detection of cholesteatoma residuals as compared with Clara and Spectra A. Thus, Spectra B may be recommended to avoid missing any cholesteatoma residuals during EES.

Assessment of jugular bulb variability based on 3D surface models: quantitative measurements and surgical implications.

PURPOSE: High-riding jugular bulbs (JBs) among other anatomical variations can limit surgical access during lateral skull base surgery or middle ear surgery and must be carefully assessed preoperatively. We reconstruct 3D surface models to evaluate recent JB classification systems and assess the variability in the JB and surrounding structures. METHODS: 3D surface models were reconstructed from 46 temporal bones from computed tomography scans. Two independent raters visually assessed the height of the JB in the 3D models. Distances between the round window and the JB dome were measured to evaluate the spacing of this area. Additional distances between landmarks on surrounding structures were measured and statistically analyzed to describe the anatomical variability between and within subjects. RESULTS: The visual classification revealed that 30% of the specimens had no JB, 63% a low JB, and 7% a high-riding JB. The measured mean distance from the round window to the jugular bulb ranges between 3.22 ± 0.97 mm and 10.34 ± 1.41 mm. The distance measurement (error rate 5%) was more accurate than the visual classification (error rate 15%). The variability of the JB was higher than for the surrounding structures. No systematic laterality was found for any structure. CONCLUSION: Qualitative analysis in 3D models can contribute to a better spatial orientation in the lateral skull base and, thereby, have important implications during planning of middle ear and lateral skull base surgery.

Signal Alteration of the Inner Ear on High-Resolution Three-Dimensional Constructive Interference in Steady State Sequence in Patients with Ménière's Disease and Labyrinthitis.

INTRODUCTION: The aim of this study is to evaluate signal alteration in the inner ear using three-dimensional (3D)-constructive interference in steady state (CISS) sequence in patients with Ménière's disease and labyrinthitis and its correlation with clinical and audiological parameters. METHODS: The medical records of the department of otorhinolaryngology were searched for patients with Ménière's disease or labyrinthitis who underwent MRI with 3D-CISS sequence. Blinded analysis of these patients and of MRI from control subjects without middle or inner ear symptoms was performed to detect any signal asymmetry of the inner ear structures. The results were correlated with clinical symptoms and results of audiological and vestibular tests. RESULTS: Fifty-eight patients with definite Ménière's disease and 5 patients with labyrinthitis as well as 41 control exams were included. A separate analysis was performed for patients with probable Ménière's disease (n = 68). A total of 172 3D-CISS sequences were analyzed by 2 blinded independent neuroradiologists. A CISS-hypointense signal of the inner ear structures was found in 3 patients with definite Ménière's disease (5.2%), in 4 patients with probable Ménière's disease (5.9%), and 2 patients with labyrinthitis (40%). No CISS hypointensity was found in the control group. Although no significant difference in symptoms or audiological test results was found between patients with and without this signal change, the side of hypointensity was frequently correlated with the symptomatic side and with hearing impairment. DISCUSSION/CONCLUSION: CISS hypointensity of the inner ear structures was evident in patients with clinical conditions other than vestibular schwannoma - more frequently in labyrinthitis than in Ménière's disease. This signal alteration was frequently encountered on the same symptomatic side as that of the pathological audiology tests, but it is not a predictor for hearing or vestibular impairment.

The effect of internet telephony and a cochlear implant accessory on mobile phone speech comprehension in cochlear implant users.

PURPOSE: In individuals with severe hearing loss, mobile phone communication is limited despite treatment with a cochlear implant (CI). The goal of this study is to identify the best communication practice for CI users by comparing speech comprehension of conventional mobile phone (GSM) calls, Voice over Internet Protocol (VoIP) calls, and the application of a wireless phone clip (WPC) accessory. METHODS: This study included 13 individuals (mean age 47.1  ± 17.3 years) with at least one CI. Frequency response and objective voice quality were tested for each device, transmission mode and the WPC. We measured speech comprehension using a smartphone for a GSM call with and without WPC as well as VoIP-calls with and without WPC at different levels of white background noise. RESULTS: Frequency responses of the WPC were limited (< 4 kHz); however, speech comprehension in a noisy environment was significantly improved compared to GSM. Speech comprehension was improved by 9-27% utilizing VoIP or WPC compared to GSM. WPC was superior in noisy environments (80 dB SPL broadband noise) compared to GSM. At lower background noise levels (50, 60, 70 dB SPL broadband noise), VoIP resulted in improved speech comprehension with and without WPC. Speech comprehension scores did not correlate with objective voice quality measurements. CONCLUSION: Speech comprehension was best with VoIP alone; however, accessories such as a WPC provide additional improvement in the presence of background noise. Mobile phone calls utilizing VoIP technology, with or without a WPC accessory, result in superior speech comprehension compared to GSM.

Using a cochlear implant processor as contralateral routing of signals device in unilateral cochlear implant recipients.

PURPOSE: In unilateral cochlear implant (CI) recipients, a contralateral routing of signals (CROS) device enables to receive auditory information from the unaided side. This study investigates the feasibility as well as subjective and objective benefits of using a CI processor as a CROS device in unilateral CI recipients. METHODS: This is a single-center, prospective cohort study. First, we tested the directionality of the CROS processor in an acoustic chamber. Second, we examined the difference of speech perception in quiet and in noise in ten unilateral CI recipients with and without the CROS processor. Third, subjective ratings with the CROS processor were evaluated according to the Client Oriented Scale of Improvement Questionnaire. RESULTS: There was a time delay between the two devices of 3 ms. Connection of the CROS processor led to a summation effect of 3 dB as well as a more constant amplification along all azimuths. Speech perception in quiet showed an increased word recognition score at 50 dB (mean improvement 7%). In noise, the head shadow effect could be mitigated with significant gain in speech perception (mean improvement 8.4 dB). This advantage was reversed in unfavorable listening situations, where the CROS device considerably amplified the noise (mean: - 4.8 dB). Subjectively, patients who did not normally wear a hearing aid on the non-CI side were satisfied with the CROS device. CONCLUSIONS: The connection and synchronization of a CI processor as a CROS device is technically feasible and the signal processing strategies of the device can be exploited. In contra-laterally unaided patients, a subjective benefit can be achieved when wearing the CROS processor.

Revision canal-wall down surgery: comparison of surgical outcomes with three different techniques.

OBJECTIVE: This study aimed to analyze the role of the endoscope in revision canal-wall down (CWD) tympanomastoid surgery and compare its use to the more traditional microscopic approach. Moreover, we aim to investigate functional outcomes of revision surgeries in a cohort of two tertiary reference centers. METHODS: A total of 103 patients undergoing revision surgery after previous CWD tympanomastoidectomy were included in the present study and divided in three groups according to the surgical technique used: endoscope exclusive (n = 22), combined (n = 35) and microscope exclusive (n = 46). Data regarding surgical indications, pre-operative clinical and audiological assessments, intraoperative findings and surgical considerations were extracted. During follow-up, data regarding anatomic and audiologic outcomes were collected and persistence or recurrence of the disease assessed. RESULTS: The most frequent sites of cholesteatoma recurrence or persistence was the anterior epitympanum. There was a statistically significant ABG improvement of - 6.02 dB HL (95% CI - 8.87 to - 3.16, p < 0.001) between pre-operative and postoperative ABG, without significant effect of surgical technique. During follow-up, no significant differences regarding disease or otorrhea control were observed. Duration of surgery and hospitalization was shorter in the endoscopic cohort without statistical significance. Intra- and postoperative complications were lower in the endoscopic group. CONCLUSION: Revision CWD surgery can take advantage of the endoscope as a minimally invasive exclusive or adjunct tool to traditional microscopic procedures. Outcome measures of endoscopic revision CWD surgery showed anatomic and functional results comparable to those of the microscopic group. The complication rate, the duration of surgery and hospitalization were favorable in the endoscopic group.

Automated alternate cover test for 'HINTS' assessment: a validation study.

OBJECTIVE: The alternate cover test (ACT) in patients with acute vestibular syndrome is part of the 'HINTS' battery test. Although quantitative, the ACT is highly dependent on the examiner's experience and could theoretically vary greatly between examiners. In this study, we sought to validate an automated video-oculography (VOG) system based on eye tracking and dedicated glasses. METHODS: We artificially induced a vertical strabismus to simulate a skew deviation on ten healthy subjects, aged from 26 to 66, using different press-on Fresnel prisms on one eye while recording eye position with VOG of the contralateral eye. We then compared the system's performance to that of a blinded trained orthoptist using conventional, semi-quantitative method of skew measurement known as the alternate prism cover test (APCT) as a gold standard. RESULTS: We found a significant correlation between the reference APCT and the Skew VOG (Pearson's R2 = 0.606, p < 0.05). There was a good agreement between the two tests (intraclass correlation coefficient 0.852, 95 CI 0.728-0.917, p < 0.001). The overall accuracy of the VOG was estimated at 80.53% with an error rate of 19.46%. There was no significant difference in VOG skew estimations compared with the gold standard except for very small skews. CONCLUSIONS: VOG offers an objective and quantitative skew measurement and proved to be accurate in measuring vertical eye misalignment compared to the ACT with prisms. Precision was moderate, which mandates a sufficient number of tests per subject.

Influence of head orientation and implantation site of a novel transcutaneous bone conduction implant on MRI metal artifact reduction sequence.

PURPOSE: The use of magnetic resonance imaging (MRI) is often limited in patients with auditory implants because of the presence of metallic components and magnets. The aim of this study was to evaluate the clinical usefulness of a customized MRI sequence for metal artifact suppression in patients with BONEBRIDGETM BCI 602 implants (MED-EL, Innsbruck, Austria), the successor of the BCI 601 model. METHODS: Using our in-house developed and customized metal artifact reduction sequence (SEMAC-VAT WARP), MRI artifacts were evaluated qualitatively and quantitatively. MRI sequences were performed with and without artifact reduction on two whole head specimens with and without the BCI 602 implant. In addition, the influence of two different implantation sites (mastoid versus retrosigmoid) and head orientation on artifact presence was investigated. RESULTS: Artifact volume was reduced by more than the 50%. Results were comparable with those obtained with the BCI 601, showing no significant differences in the dimensions of artifacts caused by the implant. CONCLUSION: SEMAC-VAT WARP was once more proved to be efficient at reducing metal artifacts on MR images. The dimensions of artifacts associated with the BCI 602 are not smaller than those caused by the BCI 601.

Bruns' nystagmus revisited: A sign of stroke in patients with the acute vestibular syndrome.

OBJECTIVE: Gaze-evoked nystagmus (GEN) is a central sign in patients with the acute vestibular syndrome (AVS); however, discriminating between a pathological and a physiologic GEN is a challenge. Here we evaluate GEN in patients with AVS. METHODS: In this prospective cross-sectional study, we used video-oculography (VOG) to compare GEN in the light (target at 15° eccentric) in 64 healthy subjects with 47 patients seen in the emergency department (ED) who had AVS; 35 with vestibular neuritis and 12 with stroke. All patients with an initial non-diagnostic MRI received a confirmatory, delayed MRI as a reference standard in detecting stroke. RESULTS: Healthy subjects with GEN had a time constant of centripetal drift >18 s. VOG identified pathologic GEN (time constant ≤ 18 s) in 33% of patients with vestibular strokes, specificity was 100%, accuracy was 83%. Results were equivalent to examination by a clinical expert. As expected, since all patients with GEN had a SN in straight-ahead position, they showed the pattern of a Bruns' nystagmus. CONCLUSIONS: One third of patients with AVS due to central vestibular strokes had a spontaneous SN in straight-ahead gaze and a pathological GEN, producing the pattern of a Bruns' nystagmus with a shift of the null position. The localization of the side of the lesion based on the null was not consistent, presumably because the circuits underlying gaze-holding are widespread in the brainstem and cerebellum. Nevertheless, automated quantification of GEN with VOG was specific, and accurately identified patients in the ED with AVS due to strokes.

Impaired fixation suppression of horizontal vestibular nystagmus during smooth pursuit: pathophysiology and clinical implications.

BACKGROUND AND PURPOSE: A peripheral spontaneous nystagmus (SN) is typically enhanced or revealed by removing fixation. Conversely, failure of fixation suppression of SN is usually a sign of a central disorder. Based on Luebke and Robinson (Vision Res 1988, vol. 28 (8), pp. 941-946), who suggested that the normal fixation mechanism is disengaged during pursuit, it is hypothesized that vertical tracking in the light would bring out or enhance a horizontal SN. METHODS: Eighteen patients with acute vestibular neuritis were studied. Eye movements were recorded using video-oculography at straight-ahead gaze with and without visual fixation, and during smooth pursuit. The slow-phase velocity and the fixation suppression indices of nystagmus (relative to SN in darkness) were compared in each condition. RESULTS: During vertical tracking, the slow-phase velocity of horizontal SN with eyes near straight-ahead gaze was significantly higher (median 2.7°/s) than under static visual fixation (median 1.2°/s). Likewise, the fixation index was significantly higher (worse suppression) during pursuit (median 48%) than during fixation (median 26%). A release of SN was also suggested during horizontal pursuit, if one assumes superposition of SN on a normal and symmetrical pursuit capability.