W. P. R. Gibson

Variation in speech perception scores among children with cochlear implants.

Objective The objective of this study was to identify common factors affecting speech perception scores in children with cochlear implants. Design Speech perception data for 167 implanted children were collected at two cochlear implant centres in Melbourne and Sydney. The data comprised audition-alone scores on open-set word and sentence tests. Children were selected on the basis that they had a Nucleus 22-electrode cochlear implant. The average age of the children was 5 yr. Information was also collected about 12 factors that may have influenced speech perception scores for each child. Analysis of covariance was used to identify factors that significantly affected speech perception scores. Pearson pairwise correlation coefficients were also calculated for all factors analyzed. Results The analyses in this study identified factors that accounted for 51%, 34%, and 45% of the variance in phoneme, word and sentence perception scores. Scores decreased by 1.4 to 2.4% per year of profound deafness prior to implantation. Children who normally use oral communication scored significantly higher than children normally using sign or simultaneous oral and sign communication. Children implanted in Sydney scored higher on average than children implanted in Melbourne. Conclusions The results show that a significant part of the variation in speech perception scores is systematically related to audiological and environmental factors for each child. The reasons for significant differences between children using different communication modes or from different clinics were not identified.

Grading of endolymphatic hydrops using magnetic resonance imaging

Conclusion: Grading of endolymphatic hydrops in the vestibule and the cochlea using magnetic resonance imaging (MRI) is proposed (2008 Nagoya scale). Objective: To standardize the evaluation of endolymphatic hydrops in both the vestibule and the cochlea using MRI. Patients and methods: The endolymphatic space was evaluated after intratympanic gadolinium injection using three-dimensional fluid attenuated (3D-FLAIR) MRI and three-dimensional real inversion recovery (3D-real IR) MRI. Results: A simple three-stage grading system was acceptable for hydrops in both the vestibule and the cochlea: none, mild, and significant. In the vestibule, the grading was determined by the ratio of the area of endolymphatic space to the vestibular fluid space (sum of the endolymphatic and perilymphatic spaces). Patients with no hydrops have a ratio of one-third or less, those with mild hydrops have between one-third and a half, and those with significant hydrops have a ratio of more than 50%. In the cochlea, patients classified as having no hydrops show no displacement of Reissners membrane; those with mild hydrops show displacement of Reissners membrane but the area of the endolymphatic space does not exceed the area of the scala vestibuli; and in those with significant hydrops the area of the endolymphatic space exceeds the area of the scala vestibuli.

Predicting cochlear implant outcomes in children with auditory neuropathy.

Objective: To examine the outcome of cochlear implantation in children with auditory neuropathy (AN) and cochlear nerve deficiency (Group A). Results are compared with a cohort of children with AN and normal cochlear nerves (Group B). Study Design: Retrospective cohort study. Setting: The Sydney Cochlear Implant Centre and the Childrens Hospital at Westmead. Patients: Children younger than 15 years with bilateral profound sensorineural hearing loss and the diagnosis of AN confirmed on electrophysiologic testing. All children underwent cochlear implantation with Nucleus 24 cochlear implants from 1997 to 2006. Interventions: Magnetic resonance imaging was examined for deficiency of the vestibulocochlear nerve. Brain and inner ear abnormalities were recorded. Cochlear implant outcomes and demographic variables were compared. Main Outcome Measures: Melbourne speech perception score (MSPS) at 1 year and implant evoked electric auditory brainstem response (EABR). Results: Group A performed significantly worse on both parameters than Group B. In Group A, median MSPS was 1, compared with a median score of 4 in Group B (z = −3.010; p = 0.003). EABR was abnormal in 13 of 15 (87%) children in Group A, compared with 9 of 39 (23%) in Group B. Children in both groups with abnormal EABR had significantly worse MSPS (z = −2.780; p = 0.005). Fourteen of 15 children with cochlear nerve deficiency had associated inner ear abnormalities. Conclusion: Children with AN can have associated cochlear nerve deficiency. These patients have worse speech perception scores at 1 year post cochlear implantation, higher rates of abnormal EABR, and more associated inner ear abnormalities than children with AN and normal cochlear nerves.

Auditory neuropathy : An update

Objectives: To describe the round window electrocochleography (RWECochG) and electric auditory brainstem responses (EABR) in ears affected by auditory neuropathy (AN), and to determine if these electrophysiological tests can predict the outcome following cochlear implant surgery. Methods: A longitudinal study of all pediatric cochlear implant patients between 1994 and 2005 was undertaken. Speech perception outcomes after cochlear implantation and electrophysiological data were collected prospectively and analyzed. Some otoacoustic emissions (OAE) data were collected retrospectively during the neonatal period. All subjects were tested using round window electrocochleography (RWEcochG), auditory brainstem responses (ABR), and implant-evoked electric auditory brainstem responses (EABR). The auditory neuropathy (AN) group consisted of 39 children (78 ears) which had present OAE and absent or grossly abnormal ABR (a broad N1 component only). Results: All 78 ears from the 39 AN children showed large cochlear microphonics (CM) and an abnormal positive potential (APP) using RW ECochG. A further 21 children showed large CM and APP but had not been tested for OAE. In total, 60 children were discovered to have APP among 435 pediatric patients who received a cochlear implant. Electrically evoked ABR (EABR) from the implanted ear were normal in 45 and abnormal in 15. 46 age matched patients without large CM and APP were used as a control group. Two year postimplant scores (Melbourne categories) were: 6.27 (APP and normal EABR), 2.25 (APP and abnormal EABR) and 5.37 (control group). Mann-Whitney U Test for nonparametric data was used to test for significant difference at significance level p < 0.005 (two tailed). The APP ears which provided normal EABR had significantly better outcomes after cochlear implantation than APP ears which had abnormal EABR. Furthermore, the APP ears which provided normal EABR performed significantly better after cochlear implant surgery than the control group of patients with no OAE, appropriate ABR results and normal EABR. Conclusions: Ears affected by AN provide large CM and APP on RW ECochG. The presence of normal EABR may indicate a significantly better outcome after cochlear implant surgery than for those APP ears which had abnormal or absent EABR. Based on these findings it is suggested that the presence of APP and/ or OAE in 75% of the ears which have absent or abnormal ABR may not indicate a pathological condition affecting the auditory nerve or synapse but only survival of outer hair cells despite extensive loss of inner hair cells.

Transtympanic Electrocochleography During Glycerol Dehydration

Thirteen patients with Menieres disorder were tested using transtympanic electrocochleography during glycerol dehydration. The most common finding was a decrease in the negative summating potential and this appeared to be a more sensitive indicator of changes occurring in the cochlea than pure tone audiometry and speech discrimination. A pathophysiological explanation for this observation is offered and the possibility of using this decrease in the negative summating potential as a pointer to the prognosis of endolymphatic sac surgery is discussed.

The vestibular evoked-potential profile of Ménière’s disease

OBJECTIVE To define the ocular and cervical vestibular evoked myogenic potential (oVEMP and cVEMP) profile in Ménières Disease (MD), we studied air-conducted (AC) sound and bone-conducted vibration (BCV)-evoked responses in 77 patients and 35 controls. METHODS oVEMPs were recorded from unrectified infra-orbital surface electromyography (EMG) during upward gaze. cVEMPs were recorded from rectified and unrectified sternocleidomastoid EMG during head elevation against gravity. Responses to AC clicks delivered via headphones and BC forehead taps delivered with a mini-shaker (bone-conduction vibrator) and a triggered tendon-hammer were recorded. RESULTS In clinically definite unilateral MD (n=60), the prevalence of unilateral VEMP abnormalities was 50.0%, 10.2% and 11.9% for click, minitap and tendon-hammer evoked oVEMPs, 40.0%, 22.8% and 10.7% for click, minitap and tendon-hammer evoked cVEMPs. The most commonly observed profile was abnormality to AC stimulation alone (33.3%), followed by abnormalities to both AC and BCV stimuli (26.7%). Isolated abnormalities to BCV stimuli were rare (5%) and limited to the minitap cVEMP. The prevalence of abnormalities for each of the AC VEMPs was significantly higher than for any one BCV VEMP. For click cVEMP, click oVEMP and minitap cVEMP, average Reflex Asymmetry Ratios (AR) were significantly higher in MD compared with controls. Test results for AC cVEMP, AC oVEMP, minitap cVEMP and caloric asymmetry were significantly correlated with hearing loss. CONCLUSIONS Predominance of abnormalities in oVEMP and cVEMP responses to AC sound is characteristic of MD and indicative of saccular involvement. SIGNIFICANCE This pattern of VEMP abnormalities may enable separation of Ménières disease from other peripheral vestibulopathies.

Pediatric cochlear implants: additional disabilities prevalence, risk factors, and effect on language outcomes.

Objective To determine the prevalence of additional disabilities in a pediatric cochlear population, to identify medical and radiologic conditions associated with additional disabilities, and to identify the effect of additional disabilities on speech perception and language at 12 months postoperatively. Study Design Retrospective case review. Setting Tertiary referral center and cochlear implant program. Patients Records were reviewed for children 0 to 16 years old inclusive, who had cochlear implant–related operations over a 12-month period. Interventions Diagnostic and rehabilitative. Main Outcome Measures Additional disabilities prevalence; medical history and radiologic abnormalities; and the effect on Categories of Auditory Performance (CAP) score at 12 months postoperatively. Results Eighty-eight children having 96 operations were identified. The overall prevalence of additional disabilities (including developmental delay, cerebral palsy, visual impairment, autism and attention deficit disorder) was 33%. The main conditions associated with additional disabilities were syndromes and chromosomal abnormalities (87%), jaundice (86%), prematurity (62%), cytomegalovirus (60%), and inner ear abnormalities including cochlea nerve hypoplasia or aplasia (75%) and semicircular canal anomalies (56%). At 12 months postoperatively, almost all (96%) of the children without additional disabilities had a CAP score of 5 or greater (speech), compared with 52% of children with additional disabilities. Children with developmental delay had a median CAP score of 4, at 12 months compared with 6 for those without developmental delay. Conclusion Additional disabilities are prevalent in approximately a third of pediatric cochlear implant patients. Additional disabilities significantly affect the outcomes of cochlear implants.

Meniere's Disease: The Incidence of Hydrops in the Contralateral Asymptomatic Ear

Objective: This study analyzes the incidence of endolymphatic hydrops in the asymptomatic contralateral ear of patients with classic Menieres disease.

Evidence for surviving outer hair cell function in congenitally deaf ears

Objective/Hypothesis: The hypotheses of the study were that congenital hearing impairment in infants can result from the isolated loss of inner hair cells of the cochlea and that this is shown by the presence of abnormal positive summating potentials on round window electrocochleography. The objectives were to establish the proportion of infants with hearing loss affected, the nature of the cochlear lesion, and its etiology. And to highlight the important implications for otoacoustic emissions testing and universal neonatal screening. Study Design: A prospectively conducted consecutive cohort study with supplemental review of notes was performed. Methods: Four hundred sixty‐four children underwent round window electrocochleography and auditory brainstem response testing under general anesthesia to assess suspected hearing loss. The presence of abnormal positive potentials was recorded. Otoacoustic emissions data were collected separately and retrospectively. Results: Three hundred forty‐two children had significant bilateral congenital hearing loss. All results were from hearing‐impaired children. Abnormal positive potentials were recorded in 73 of 342 children (21%). Eighty‐three percent of children with otoacoustic emissions also had abnormal positive potentials, but only 14% of children without otoacoustic emissions had abnormal positive potentials (P < .001). In the neonatal intensive care unit setting, 43% of infants were found to have abnormal positive potentials, whereas only 10% had abnormal positive potentials if not in the neonatal intensive care unit setting (P < .001). Abnormal positive potentials were present in 63% of infants born before 30 weeks gestation and in 14% of infants born at term (P < .001). Abnormal positive potentials were identified in 57% of infants with documented hypoxia and 11% of children with no episodes (P < .001). Otoacoustic emissions were present in 48% of infants from the neonatal intensive care unit, despite their hearing loss. Conclusion: Both otoacoustic emissions and abnormal positive potentials may originate from outer hair cell activity following inner hair cell loss. This may occur in more than 40% of hearing‐impaired children in the neonatal intensive care unit setting. Chronic hypoxia is the most likely cause. Otoacoustic emissions testing may not be a suitable screening tool for such infants.

A comparison of two methods of using transtympanic electrocochleography for the diagnosis of Meniere's disease: click summating potential/action potential ratio measurements and tone burst summating potential measurements

Conclusion: Transtympanic electrocochleography (TT ECochG) is helpful for the confirmation of Menieres disease using tone burst stimuli to measure the amplitude of the frequency specific summating potentials (SP) but not when using the click evoked summating potential versus action potential ratio (SP/AP). Objectives: To evaluate the effectiveness of TT ECochG as a means of confirming the clinical diagnosis of Menieres disease. Patients and methods: A total of 2717 patients were referred for TT ECochG between August 1998 and September 2008. Each patient was assessed prospectively on clinical grounds according to the AAOHNS criteria and a scale devised by the author. A Menieres group and a non-Menieres group were determined and the TT ECochG results were compared between the groups that had similar hearing levels for the particular stimulus employed. Results: Click SP/AP measurements did not significantly differentiate between populations of Menieres ears and non-Menieres ears. Tone burst SP amplitude measurements were significantly different between the populations, especially using frequencies at 500 Hz, 1 kHz, and 2 kHz.