Post Cochlear Implantation Vertigo: Ictal Nystagmus and Audiovestibular Test Characteristics.

OBJECTIVE: To investigate ictal nystagmus and audiovestibular characteristics in episodic spontaneous vertigo after cochlear implantation (CI). STUDY DESIGN: Retrospective and prospective case series. PATIENTS: Twenty-one CI patients with episodic spontaneous vertigo after implantation were recruited. INTERVENTIONS: Patient-initiated home video-oculography recordings were performed during one or more attacks of vertigo, using miniature portable home video-glasses. To assess canal and otolith function, video head-impulse tests (vHITs) and vestibular-evoked myogenic potential tests were conducted. MAIN OUTCOME MEASURES: Nystagmus slow-phase velocities (SPVs), the presence of horizontal direction-changing nystagmus, and post-CI audiovestibular tests. RESULTS: Main final diagnoses were post-CI secondary endolymphatic hydrops (48%) and exacerbation of existing Ménière's disease (29%). Symptomatic patients demonstrated high-velocity horizontal ictal-nystagmus (SPV, 44.2°/s and 68.2°/s in post-CI secondary endolymphatic hydrop and Ménière's disease). Direction-changing nystagmus was observed in 80 and 75%. Two were diagnosed with presumed autoimmune inner ear disease (SPV, 6.6°/s and 172.9°/s). One patient was diagnosed with probable vestibular migraine (15.1°/s).VHIT gains were 0.80 ± 0.20 (lateral), 0.70 ± 0.17 (anterior), and 0.62 ± 0.27 (posterior) in the implanted ear, with abnormal values in 33, 35, and 35% of each canal. Bone-conducted cervical and ocular vestibular-evoked myogenic potentials were asymmetric in 52 and 29% of patients (all lateralized to the implanted ear) with mean asymmetry ratios of 51.2 and 35.7%. Reversible reduction in vHIT gain was recorded in three acutely symptomatic patients. CONCLUSION: High-velocity, direction-changing nystagmus time-locked with vertigo attacks may be observed in post-CI implant vertigo and may indicate endolymphatic hydrops. Fluctuating vHIT gain may be an additional marker of a recurrent peripheral vestibulopathy.

Impact of Cochlear Implantation on Canal and Otolith Function.

OBJECTIVE: To quantify the impact of cochlear implantation (CI) on all five vestibular end-organs and on subjective ratings of post-CI dizziness. METHODS: Seventy-two patients undergoing unilateral CI were recruited for the study. All participants completed pre- and post-CI three-dimensional video head-impulse tests (3D vHITs) to assess semicircular-canal (SC) function, air- and bone-conducted (AC and BC) cervical and ocular vestibular-evoked myogenic potentials (cVEMPs and oVEMPs) to assess otolith-function and the dizziness handicap inventory (DHI) to measure self-perceived disability. RESULTS: Nineteen percent of patients reported new or worsened dizziness postsurgery. Post-CI abnormalities (new lesions and significant deteriorations) were seen in the AC cVEMP (48%), AC oVEMP (34%), BC cVEMP (10%), and BC oVEMP (7%); and lateral (L) (17%), posterior (P) (10%), and anterior (A) (13%) SC vHITs. CI surgery was more likely to affect the AC cVEMP compared with the other tests (χ2 test, p < 0.05). Fifty percent of patients reported no dizziness pre- and postsurgery. In the implanted ear, normal pre-CI vHIT gain was preserved in lateral semicircular canal (LSC) (69%), anterior semicircular canal (ASC) (74%), and posterior semicircular canal (PSC) (67%), and normal reflex amplitudes were found in AC cVEMP (25%), AC oVEMP (20%), BC cVEMP (59%), and BC oVEMP (74%). Statistically significant decreases were observed in LSC vHIT gain, AC cVEMP amplitude, and AC oVEMP amplitude postsurgery (p < 0.05). There was a significant moderate positive correlation between change in DHI scores and the summed vestibular deficit postsurgery (r(51) = 0.38, p < 0.05). CONCLUSION: CI can impact tests that assess all five vestibular end-organs and subjective ratings of dizziness. These results support pre and post-surgical vestibular testing and assist preoperative counseling and candidate selection.

Naunton's Masking Dilemma Revisited.

BACKGROUND: Pure-tone audiometry is essential in diagnosing clinical hearing loss. Masking of the nontest ear is mandatory for determining accurate hearing thresholds in the presence of asymmetrical levels between the two ears and for ascertaining the presence of a conductive hearing loss. Paradoxically, over masking occurs when the intensity of the required masking noise to the contralateral ear is such that it exceeds interaural cranial attenuation by an amount sufficient to mask the test ear. Ralph F Naunton was the first to describe this phenomenon, which has since been known as "Naunton's masking dilemma." METHODS: A formula was derived mathematically to predict when Naunton's masking dilemma might occur in air and bone conduction. Review of Ralph F Naunton's primary works and related publications was performed. RESULTS: Our derived mathematical formulae predict when "Naunton's masking dilemma" may occur. During air conduction testing, a masking dilemma may occur when the sum of the air/bone gaps is greater than or equal to twice the interaural attenuation minus 15 dB (Σ ABGNTE+TE ≥ 2 × IA - 15 dB). During bone conduction testing, a masking dilemma may occur when the air-bone gap of the nontest ear is greater than or equal to the interaural attenuation minus 15 dB (ABGNTE ≥ IAAIR - 15 dB). CONCLUSION: Naunton's masking dilemma imposes a significant limitation to conventional audiometric testing. To the best of our knowledge, we think this is the first time that Naunton's masking dilemma has been represented in a simplified mathematical equation.

Improving sound localization after cochlear implantation and auditory training for the management of single-sided deafness.

OBJECTIVE: To report a successful case of cochlear implantation and auditory training for the improvement of sound localization in a patient with single-sided deafness. STUDY DESIGN: Case report and literature review. SETTING: Tertiary referral otology practice. PATIENT: Fifty-seven-year-old man receiving cochlear implantation after 8 years of unilateral sensorineural hearing loss. INTERVENTION: Initially, CROS hearing aid, then osseointegrated bone conduction system and finally cochlear implantation and auditory training. MAIN OUTCOME MEASURES: Sound localization tests. RESULT: Sound localization tests after CI and auditory training showed improvement when compared with testing performed after fitting of an osseointegrated bone conduction system. CONCLUSION: Cochlear implantation followed by 3 months of auditory training may have improved sound localization in this patient with single-sided deafness. Further case-controlled studies need to be undertaken to ascertain whether CI alone without formal auditory training will promote the same results.

Cochlear implantation in patients with bilateral severe sensorineural hearing loss after major blunt head trauma.

OBJECTIVE: To highlight issues that impact on cochlear implant candidacy and performance in individuals who have severe bilateral sensorineural hearing loss after major blunt head trauma. STUDY DESIGN: Retrospective case review. SETTING: Tertiary level neurotology center. PATIENTS: Twenty-five patients treated at our institution for severe hearing loss after blunt head trauma INTERVENTION: Assessment of cochlear implant candidacy criteria and postimplant outcomes in patients presenting with severe hearing loss after major blunt head trauma MAIN OUTCOME MEASURES: Cause of injury, pure tone audiology, open set speech perception (preimplant and postimplant), promontory stimulation, and imaging results. RESULTS: Of the 25 patients with severe hearing loss, 11 ultimately underwent cochlear implantation. Fall from a height was the most common cause of injury. Five patients experienced bilateral temporal bone fractures. Seventeen patients satisfied candidacy criteria for implantation. For those patients who did undergo cochlear implantation, the mean postimplant open set speech recognition score was 71. Issues related to cochlear implant candidacy and outcomes for implantation will be discussed. CONCLUSION: Severe hearing loss after major blunt head trauma presents a number of unique clinical challenges. A significant number of these patients are not suitable for cochlear implantation for a variety of reasons. Clinicians working in the area of cochlear implantation should be aware of the various problems that can impact on effective cochlear implantation in such patients.

Medical and noninvasive therapy for Meniere's disease.

Nonoperative therapy continues to be the mainstay of treatment of patients suffering from Meniere disease. Despite extensive research, the exact pathogenesis of Meniere disease remains elusive. The poorly understood nature of this condition has made it nearly impossible to develop treatments that are curative. Most modern treatments are aimed at controlling symptoms. This article reviews the various nonoperative treatments that have been used to treat Meniere disease historically as well as outlining the authors' clinical treatment paradigm.

Surgical management of Ludwig's angina.

BACKGROUND: Ludwig's angina (LA) is a dangerous surgical condition that can cause severe airway compromise and death. There is controversy regarding the best way to manage the airway of patients with LA. Options range from conservative management involving close observation and i.v. antibiotics to airway intervention, including tracheostomy and endotracheal intubation using fibre-optic nasoendoscopy. We present evidence supporting a role for conservative airway management in a select subset of patients. METHODS: This paper reviews 9 years' experience of treating patients with LA at Liverpool Hospital. RESULTS: Twenty-one out of 29 (72%) of our patients were treated conservatively following initial clinical assessment. One of these patients subsequently deteriorated requiring emergency intubation. Of those treated non-conservatively at initial presentation, seven patients were able to be intubated using fibre-optic nasoendoscopy and one patient required tracheostomy under local anaesthesia. CONCLUSION: A general discussion of issues related to the management of LA is presented. Based on our experience we conclude that there is a subset of patients with LA who can be managed safely with conservative management.