Ana H. Kim

Analysis of speech perception outcomes among patients receiving cochlear implants with auditory neuropathy spectrum disorder.

Objective Cochlear implantation (CI) is currently the main device option for children with auditory neuropathy spectrum disorder (ANSD) who receive minimal benefit from conventional amplification. This study examines potential prognostic factors associated with post-CI speech performance in this population. Study Design Retrospective chart review. Setting Academic center. Patients ANSD patients without inner ear abnormalities implanted with unilateral or bilateral CI between 1998 and 2010. Intervention CI and speech perception testing. Main Outcome Measure Post-CI speech perception testing at 50 dBHL. “Good” performers were defined as patients with greater than 70% speech perception and “poor” performers less than 70%. Medical comorbidity, educational information, and social history were gathered. Results Twenty-seven patients met inclusion criteria. Mean age at diagnosis, first CI, and second CI in good performers were 2.5 ± 3.4, 3.4 ± 3.6, and 3.8 ± 1.6 years, respectively, compared with 9.7 ± 7.8, 14.8 ± 12.9, and 8.9 ± 3.5 in poor performers. Mean speech perception after first and second implantation for good performers trended at 85% and 90%, respectively, compared with 36% and 73% in poor performers. Better pre-CI PTA correlated with better post-CI speech perception. Patients with bilateral CI demonstrated better speech perception outcomes compared with unilateral CI use. Poor performers had later age of implantation, lower socioeconomic status, and lack of family support compared with good performers. Conclusion ANSD patients who do not benefit from conventional amplification do well when implanted at a young age with proper access to education and habilitation training. Medical, social, and economic information may be helpful in predicting positive outcomes.

A new comprehensive cochlear implant questionnaire for measuring quality of life after sequential bilateral cochlear implantation.

Objective To develop a comprehensive cochlear implant questionnaire (CCIQ) as a tool for assessing changes in quality of life (QoL) after receiving a second cochlear implant (CI2) and to correlate the QoL with speech perception changes after CI2. Study Design Retrospective case series with planned data collection. Setting Academic cochlear implant center. Patients Ninety-eight English-speaking adults who received CI2 between 2000 and 2011. Intervention CCIQ is a 28-item, 5-point Likert-scale questionnaire that assesses the physical and psychosocial benefits of CI2. Main Outcome Measures Test-retest reliability and Cronbach’s alpha internal consistency were used to assess the reliability of the CCIQ. Speech perception was tested using CNC and HINT. Results Fifty-four patients completed the CCIQ, and 26 were retested. Respondents reported a subjective improvement in all domains. Test-retest reliability was satisfactory, with 64% of items achieving an intraclass correlation coefficient of greater than 0.6. Internal consistency reliability was excellent for the overall measure and was satisfactory for 6 of 9 subdomains. Speech perception data were available for 22 patients. Average CNC scores improved 13 ± 16%, and HINT scores improved 42 ± 16%. No statistically significant correlation was found between QoL scores and audiometric data or duration of CI2 use. Conclusion Our preliminary data indicate that this CCIQ is a promising tool in assessing QoL specific to CI2 patients. Overall, patients reported improved QoL, independent of speech perception scores. Further refinements of the questionnaire with larger patient numbers are needed to strengthen the CCIQ.

Dexamethasone’s Effect in the Retrocochlear Auditory Centers of a Noise-Induced Hearing Loss Mouse Model

Objective Examine prophylactic effects of dexamethasone (Dex) in retrocochlear auditory centers in a noise-induced hearing loss (NIHL) mouse model. Study Design Prospective animal study. Setting Academic research center. Subjects and Methods Thirty-two mice were divided into control, untreated, saline (2 and 10 µL), and Dex (2 and 10 µL) groups. Dex was applied intratympanically (IT) prior to 110 to 120 dB noise over 6 hours. Auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) were performed at 1 day, 1 week, 1 month, and 2 months. Retrocochlear neuronal cells were labeled with FluoroGold and counted. Hair cells of the organ of Corti were labeled with fluorescein isothiocyanate-conjugated phalloidin and counted. Results Auditory brainstem response thresholds of untreated NIHL, 2 and 10 µL IT saline, and 2 and 10 µL IT Dex were 21.7 ± 2.9 dB, 20 ± 0 dB, 20 ± 5 dB, 18.3 ± 2.9 dB, and 18.3 ± 2.9 dB, respectively. At 1-day post NIHL, all groups demonstrated profound hearing loss. At 2 weeks, 2 and 10 µL Dex thresholds improved to 47.5 ± 3.5 dB and 48.8 ± 18.9 dB, respectively, whereas the untreated and saline groups remained unchanged. Mean cell counts in the cochlear nucleus (CN), superior olivary complex (SOC), and lateral lemniscus (LL) of control mice were 1483 ± 190, 2807 ± 67, and 112 ± 20, respectively. After acoustic trauma, the untreated, saline, and 2 µL Dex groups yielded decreased neuronal counts in the SOC. In contrast, the 10 µL Dex group had 1883 ± 186 (CN), 2774 ± 182 (SOC), and 166 ± 18 (LL). There was sporadic hair cell loss for all traumatized groups. Conclusion Our NIHL mouse model demonstrated dose-dependent Dex pretreatment otoprotection against NIHL with preservation of retrocochlear auditory neurons.

Connexin 43 and hearing: Possible implications for retrocochlear auditory processing

To examine the relationship between hearing and connexin 43, a dominant gap junctional protein in the central nervous system.

Specific targeting of retrocochlear auditory pathway for optimal pharmacotherapy delivery using a mouse model.

Hypothesis Optimal pharmacotherapy entails a safe delivery method that specifically targets auditory structure(s) of interest. A retrocochlear neuronal tracer may enable comparison of various pharmacotherapy delivery methods and localization of the drug along the auditory pathway. Background Sensorineural hearing loss (SNHL) can involve cochlear hair cell or neural cell death, which often is accompanied by secondary degeneration of central auditory neurons. Targeting the precise location of nerve degeneration is important for treatment success. To be clinically relevant, the method of drug delivery must be safe and reliable while being maximally absorbed by the relevant inner ear structures of interest. Methods We compared 3 methods of FluoroGold (FG) delivery, a retrograde neuronal tracer, in delineating the retrocochlear auditory pathway using a normal-hearing strain of CBA mice. FG was delivered either intratympanic (IT), intracochlear (IC), or through the round window (RW). Five days after FG injection, mice were sacrificed for cell counts in the cochlear nucleus (CN), superior olivary complex (SOC), and the lateral lemniscus (LL). Results Although neurons in the CN and SOC were abundantly labeled by FG in all 3 injection methods, the IT method was the most reproducible and specific. The average cells for the CN, SOC, and LL were 851 ± 121, 2629 ± 367, and 112 ± 30, respectively. Accurate cell counts could not be established for the IC and RW injection methods because of nonspecific cell staining. Only 1 of the 5 IC-injected mice had specific labeling along the retrocochlear auditory pathway. Cell counts for the single mouse with specific IC staining in the CN, SOC, and LL were 177, 1839, and 56, respectively. Similarly, 2 of the 5 RW-injected mice had specific labeling, whereas the rest were nonspecific. The average cell counts for the 2 mice with specific labeling in the CN, SOC, and LL was 723.5 ± 580.0, 2173.5 ± 998.0, and 131.5 ± 8.0, respectively. Conclusion The IT injection method resulted in reproducible, specific staining of neuronal cells along the retrocochlear auditory pathway compared with the RW or IC route of delivery.

Normative data for rotational chair stratified by age

The purpose of this study is to examine the range of vestibulo‐ocular reflex (VOR) gain on rotary chair (RC) testing in subjects without ear and vestibular problems stratified by age and gender.

Mouse Model to Study the Effect of Noise-Induced Hearing Loss on the Retrocochlear Auditory Neurons

Objectives: To create a noise-induced hearing loss (NIHL) mouse model to examine its effect on neuronal cells in the cochlear nucleus (CN), superior olivary complex (SOC), and lateral lemniscus (LL). Methods: Three month old CBA male mice were exposed to 110-120dB noise over 6 hours. Auditory brainstem response (ABR) tested at 1-day, 1-week, 1-month, and 2-months after acoustic trauma (AT) confirmed profound hearing loss. Distortion product otoacoustic emission (DPOAE) remained present after AT. FluoroGold (FG) was injected through the right tympanic membrane for retrocochlear neuronal staining. Results: The average click ABR threshold shifts were 55dB, 55dB, 45dB, and 48dB after 1-day, 1-week, 1-month, and 2-months post-AT, respectively. The average tonal ABR threshold shifts from 8-28 kHz were 51dB, 50.5dB, 49.8dB, and 43.8dB after 1-day, 1-week, 1-month, and 2-months, respectively. DPOAE signals from 12-28 kHz were present at higher thresholds (14.3dB, 12.7dB, 13dB, and 17dB after 1-day, 1-week, 1-month, and 2-months, respectively) after the NIHL. The average neuronal cell counts in the CN, SOC, LL, and contralateral SOC in deafened mice were 1390 ± 404, 2083 ± 190, 104 ± 21, and 163 ± 27, respectively; compared to 1483 ± 190, 2807 ± 67, 112 ± 20, and 208 ± 23, respectively, in control mice. The SOC yielded the only statistically significant difference between the two groups (P < 0.05). Conclusions: A reliable NIHL mouse model has been established. At 2-months post-deafening, we found significant decrease in neuronal cells in the SOC. This model serves as a tool to further investigate protective pharmacotherapy against NIHL.

Primary Middle Ear Meningioma and Dural/ Ophthalmic Artery Aneurysm

Primary Middle Ear Meningioma and Dural/ Ophthalmic Artery Aneurysm Meningiomas are the second most common brain tumor. Though most are found intracranially, a few exhibit extracranial extension. Even fewer meningiomas are found extracranially without an intracranial component. We present a case of a 50 year old woman diagnosed with meningioma of the middle ear. Concurrent dural and ophthalmic artery aneurysms were also found on imaging.

Assessing Quality of Life in Bilateral Cochlear Implants

Objective: 1) Validate a newly developed Comprehensive Cochlear Implant Questionnaire (CCIQ) as a tool for assessing changes in quality of life after receiving a second cochlear implant (CI) in the contralateral ear. 2) Correlate speech perception changes after the second CI with quality of life. Method: CCIQ is a 28-item, 5-point Likert-scale questionnaire that assesses physical and psychosocial benefits of CI. This was administered to patients who received bilateral CI at our center. Test-retest reliability and Cronbach’s alpha were used to validate the CCIQ. Speech perception was tested using CNC, HINT, and AZBio. Results: We identified 103 adult bilateral CI patients from 2004 to 2011. Of 58 respondents, 21 completed a retest CCIQ. Test-retest reliability was satisfactory, with 60% of items greater than 0.6. Coefficients for 6 of the 9 subdomains exceeded 0.6. Data suggest that internal consistency was acceptable (>0.7) for domains speech perception in quiet and noise, localization, and music, and good (>0.80) for subdomain vestibular effects. Descriptive statistics for speech perception on CNC were 62.4 ± 22.5% and 70.5 ± 18.4% using one versus bilateral CI, respectively. HINT scores were 68.0 ± 36.8% and 83.7 ± 15.4%, and AZBio 63.5 ± 34.6% and 91.6 ± 8.6%. Conclusion: Early CCIQ data indicate this as a promising measure in assessing quality of life specific to bilateral CI patients. Overall, patients reported improved quality of life. Quantitative data on speech perception demonstrate increased trend in audiometric scores after the second CI. However, further testing is needed to strengthen these findings.