Cross-modal plasticity in children with cochlear implant: converging evidence from EEG and functional near-infrared spectroscopy.

Over the first years of life, the brain undergoes substantial organization in response to environmental stimulation. In a silent world, it may promote vision by (i) recruiting resources from the auditory cortex and (ii) making the visual cortex more efficient. It is unclear when such changes occur and how adaptive they are, questions that children with cochlear implants can help address. Here, we examined 7-18 years old children: 50 had cochlear implants, with delayed or age-appropriate language abilities, and 25 had typical hearing and language. High-density electroencephalography and functional near-infrared spectroscopy were used to evaluate cortical responses to a low-level visual task. Evidence for a 'weaker visual cortex response' and 'less synchronized or less inhibitory activity of auditory association areas' in the implanted children with language delays suggests that cross-modal reorganization can be maladaptive and does not necessarily strengthen the dominant visual sense.

Dynamic networks differentiate the language ability of children with cochlear implants.

Background: Cochlear implantation (CI) in prelingually deafened children has been shown to be an effective intervention for developing language and reading skill. However, there is a substantial proportion of the children receiving CI who struggle with language and reading. The current study-one of the first to implement electrical source imaging in CI population was designed to identify the neural underpinnings in two groups of CI children with good and poor language and reading skill. Methods: Data using high density electroencephalography (EEG) under a resting state condition was obtained from 75 children, 50 with CIs having good (HL) or poor language skills (LL) and 25 normal hearing (NH) children. We identified coherent sources using dynamic imaging of coherent sources (DICS) and their effective connectivity computing time-frequency causality estimation based on temporal partial directed coherence (TPDC) in the two CI groups compared to a cohort of age and gender matched NH children. Findings: Sources with higher coherence amplitude were observed in three frequency bands (alpha, beta and gamma) for the CI groups when compared to normal hearing children. The two groups of CI children with good (HL) and poor (LL) language ability exhibited not only different cortical and subcortical source profiles but also distinct effective connectivity between them. Additionally, a support vector machine (SVM) algorithm using these sources and their connectivity patterns for each CI group across the three frequency bands was able to predict the language and reading scores with high accuracy. Interpretation: Increased coherence in the CI groups suggest overall that the oscillatory activity in some brain areas become more strongly coupled compared to the NH group. Moreover, the different sources and their connectivity patterns and their association to language and reading skill in both groups, suggest a compensatory adaptation that either facilitated or impeded language and reading development. The neural differences in the two groups of CI children may reflect potential biomarkers for predicting outcome success in CI children.

Auditory evoked response to an oddball paradigm in children wearing cochlear implants.

OBJECTIVE: Although children with cochlear implants (CI) achieve remarkable success with their device, considerable variability remains in individual outcomes. Here, we explored whether auditory evoked potentials recorded during an oddball paradigm could provide useful markers of auditory processing in this pediatric population. METHODS: High-density electroencephalography (EEG) was recorded in 75 children listening to standard and odd noise stimuli: 25 had normal hearing (NH) and 50 wore a CI, divided between high language (HL) and low language (LL) abilities. Three metrics were extracted: the first negative and second positive components of the standard waveform (N1-P2 complex) close to the vertex, the mismatch negativity (MMN) around Fz and the late positive component (P3) around Pz of the difference waveform. RESULTS: While children with CIs generally exhibited a well-formed N1-P2 complex, those with language delays typically lacked reliable MMN and P3 components. But many children with CIs with age-appropriate skills showed MMN and P3 responses similar to those of NH children. Moreover, larger and earlier P3 (but not MMN) was linked to better literacy skills. CONCLUSIONS: Auditory evoked responses differentiated children with CIs based on their good or poor skills with language and literacy. SIGNIFICANCE: This short paradigm could eventually serve as a clinical tool for tracking the developmental outcomes of implanted children.

Real-time measurement of stapes motion and intracochlear pressure during blast exposure.

Blast-induced auditory injury is primarily caused by exposure to an overwhelming amount of energy transmitted into the external auditory canal, the middle ear, and then the cochlea. Quantification of this energy requires real-time measurement of stapes footplate (SFP) motion and intracochlear pressure in the scala vestibuli (Psv). To date, SFP and Psv have not been measured simultaneously during blast exposure, but a dual-laser experimental approach for detecting the movement of the SFP was reported by Jiang et al. (2021). In this study, we have incorporated the measurement of Psv with SFP motion and developed a novel approach to quantitatively measure the energy flux entering the cochlea during blast exposure. Five fresh human cadaveric temporal bones (TBs) were used in this study. A mastoidectomy and facial recess approach were performed to identify the SFP, followed by a cochleostomy into the scala vestibuli (SV). The TB was mounted to the "head block", a fixture to simulate a real human skull, with two pressure sensors - one inserted into the SV (Psv) and another in the ear canal near the tympanic membrane (P1). The TB was exposed to the blast overpressure (P0) around 4 psi or 28 kPa. Two laser Doppler vibrometers (LDVs) were used to measure the movements of the SFP and TB (as a reference). The LDVs, P1, and Psv signals were triggered by P0 and recorded simultaneously. The results include peak values for Psv of 100.8 ± 51.6 kPa (mean ± SD) and for SFP displacement of 72.6 ± 56.4 µm, which are consistent with published experimental results and finite element modeling data. Most of the P0 input energy flux into the cochlea occurred within 2 ms and resulted in 10-70 µJ total energy entering the cochlea. Although the middle ear pressure gain was close to that measured under acoustic stimulus conditions, the nonlinear behavior of the middle ear was observed from the elevated cochlear input impedance. For the first time, SFP movement and intracochlear pressure Psv have been successfully measured simultaneously during blast exposure. This study provides a new methodology and experimental data for determining the energy flux entering the cochlea during a blast, which serves as an injury index for quantifying blast-induced auditory damage.

Primary Dural Repair Using Titanium Microclips Following Lateral Skull Base Surgery.

Objective Standard techniques for primary dural repair following lateral skull base surgery are both technically challenging and time consuming without the potential for primary dural repair. Inadequate closure may result in postoperative cerebrospinal fluid (CSF) leak infectious sequalae. Traditional methods of dural repair rely on secondary obliteration of the CSF fistula. We hypothesized that the use of nonpenetrating titanium microclips may serve as a useful adjunct in primary dural repair or the establishment of an immobile repair layer following lateral skull base surgery. Methods Here, we report a novel technique for primary dural repair using nonpenetrating titanium microclips as an adjunct to standard techniques in a series of six patients with lateral skull base pathologies. Results A total of six consecutive lateral skull base tumor patients with titanium microclip dural reconstruction were included in our case series. Lateral skull base pathologies represented in this group included two jugular foramen schwannomas, one vestibular schwannoma, one petroclival meningioma, one glomus jugulare paraganglioma, and one jugular foramen chordoid meningioma. Conclusion To our knowledge, this is the first report on the use of microclips in repairing dural defects following lateral skull base surgery. Surgical outcomes for this small case series suggest that dural repair of the later skull base with nonpenetrating titanium microclips is a useful adjunct in dural repair following lateral skull base surgery.

Factors Associated with Speech-Recognition Performance in School-Aged Children with Cochlear Implants and Early Auditory-Verbal Intervention.

BACKGROUND: Considerable variability exists in the speech recognition abilities achieved by children with cochlear implants (CIs) due to varying demographic and performance variables including language abilities. PURPOSE: This article examines the factors associated with speech recognition performance of school-aged children with CIs who were grouped by language ability. RESEARCH DESIGN: This is a single-center cross-sectional study with repeated measures for subjects across two language groups. STUDY SAMPLE: Participants included two groups of school-aged children, ages 7 to 17 years, who received unilateral or bilateral CIs by 4 years of age. The High Language group (N = 26) had age-appropriate spoken-language abilities, and the Low Language group (N = 24) had delays in their spoken-language abilities. DATA COLLECTION AND ANALYSIS: Group comparisons were conducted to examine the impact of demographic characteristics on word recognition in quiet and sentence recognition in quiet and noise. RESULTS: Speech recognition in quiet and noise was significantly poorer in the Low Language compared with the High Language group. Greater hours of implant use and better adherence to auditory-verbal (AV) therapy appointments were associated with higher speech recognition in quiet and noise. CONCLUSION: To ensure maximal speech recognition in children with low-language outcomes, professionals should develop strategies to ensure that families support full-time CI use and have the means to consistently attend AV appointments.

Impact and Cost Effectiveness of Videonystagmography.

OBJECTIVE: Videonystagmography (VNG) is a commonly ordered test to evaluate patients with vestibular complaints. To date, there are no evidence-based guidelines for evaluating patients presenting with vestibular symptoms. This study evaluates the cost effectiveness of VNG and the impact of VNG findings on patient management. METHODS: Patient charts were reviewed from 3 institutions to collect the pre- and post-VNG ICD-9/10 diagnosis and treatment plan. VNG findings were recorded to calculate the incidence of abnormal findings and the incidence of change in diagnosis and/or treatment plan. The cost effectiveness of VNG was estimated based on these calculations. RESULTS: A total of 120 patient charts were reviewed. 69/120 (57.5%; 95% CI: 48.2%-66.5%) patients had abnormal findings on their VNG. A change in diagnosis was noted in 24/120 (20.0%; 95% CI: 13.3%-28.3%) patients. A change in treatment plan was noted in 62/120 (51.7%; 95% CI: 42.4%-60.9%) patients, and 11/120 (9.2%; 95% CI: 4.7%-15.8%) had a change in diagnosis that led to change in treatment plan. Using the average Medicare reimbursement for VNG, the cost effectiveness analysis showed a cost of $869.57 per VNG with abnormal findings and a cost of $5454.55 per VNG that lead to a change in diagnosis and treatment plan. CONCLUSIONS: VNG findings may not result in changes in clinical diagnosis. However, VNG is impactful at influencing treatment plan changes. VNG results are beneficial for counseling patients, guiding treatment plans, and managing patient expectations. When there is a clear indication, VNG testing can be cost effective in managing patients presenting with vestibular symptoms.

Temporal Bone and Cerebellopontine Angle Epidermoid Resulting in Facial Nerve Paralysis: Resection and Facial Nerve Coaptation.

Objectives Demonstrate the utilization of a transcochlear approach for resection of an epidermoid involving the temporal bone and cerebellopontine angle (CPA) with end-to-end facial nerve coaptation. Designs Single case-based operative video. Setting Tertiary center with dedicated skull base team. Participants The patient is a 50-year-old left handed male with a history of a remote left Bell's palsy, left sudden sensorineural hearing loss, and a rapidly progressive facial nerve paralysis. His balance was impaired, and his videonystagmography showed a significant left sided peripheral vestibular weakness. Computed tomography (CT) scan showed an erosive lesion of his left temporal bone involving the cochlea and semicircular canals, and magnetic resonance imaging (MRI) showed a T2 hyperintense lesion with restricted diffusion and no enhancement on postcontrast T1 sequences. Main Outcome Measures Gross total resection of the epidermoid, recovery of facial nerve function, balance improvement. Results The patient underwent resection via a transcochlear approach. The tumor involved the epitympanum and eroded the semicircular canals, vestibule, and basal turn of the cochlea. Gross total tumor resection was attained. The facial nerve was isolated in the mastoid and tympanic segments, traced proximally to the geniculate ganglion, and then into the internal auditory canal (IAC). The nerve was discontinuous in the distal IAC and a reactive neuroma was resected. The facial nerve was mobilized and an end-to-end coaptation was performed in the CPA using a collagen tubule. The 3-month postoperative MRI showed no residual or recurrent disease. His postoperative balance was improved. Partial facial nerve recovery is not expected prior to 9 to 12 months. The link to the video can be found at: https://youtu.be/C6N8qPwBt2Y .

Microvascular Decompression and Nervus Intermedius Sectioning for the Treatment of Geniculate Neuralgia.

Objectives Demonstrate the surgical treatment of geniculate neuralgia via microvascular decompression and nervus intermedius sectioning. Designs Single case-based operative video. Setting Tertiary center with dedicated skull base team. Participants The patient is a 62-year-old female with a history of deep right-sided otalgia consistent with geniculate neuralgia. She failed appropriate medical treatment. Her magnetic resonance imaging (MRI) showed an ectatic vertebrobasilar system as well as an anterior inferior cerebellar artery (AICA) loop causing compression of the VII/VIII nerve complex in the cerebellopontine angle. Main Outcome Measures Resolution of right-sided otalgia. Results The patient underwent retrosigmoid craniotomy with microvascular decompression of the VII/VIII nerve complex and nervus intermedius sectioning. Intraoperatively, the patient was noted to have an ectatic vertebral artery and AICA that were compressing the root entry zone of the VII/VIII nerve complex. Microvascular decompression was performed of both the vertebral artery and AICA with Teflon. The nervus intermedius was sharply sectioned. The patient's postoperative course was uneventful with no complications. She continues to have resolution of her right sided otalgia at 6 months postoperatively. The link to the video can be found at: https://youtu.be/uRb_QfrINSk .

Endovascular treatment of a temporal bone pseudoaneurysm presenting as bloody otorrhea.

Objective This case report is designed to illustrate an uncommon presentation of osteoradionecrosis (ORN) of the temporal bone and a treatment method for bloody otorrhea from a pseudoaneurysm of the internal carotid artery (ICA). Design This is a single patient case report Setting University of Missouri-Columbia Hospital and Clinics. Participants The report describes a patient with a history of hypopharyngeal squamous cell carcinoma (SCCA) who was previously treated with chemoradiation therapy and salvage bilateral neck dissections and then presented in a delayed fashion with profuse, episodic bloody otorrhea. Computed tomography (CT) was consistent with ORN of the temporal bone. The patient underwent emergent cerebral angiography. A pseudoaneurysm of the cervicopetrous ICA was confirmed to be the source of the patient's bloody otorrhea. The lesion was treated by endovascular sacrifice of the ICA using the two-catheter coiling technique. Results The patient had no neurologic sequelae or further bleeding after treatment. Conclusions Bloody otorrhea is an uncommon presentation of ORN. Sacrifice of the internal carotid can be considered as a treatment when the source is pseudoaneurysmal.

Utilization of preoperative cerebrospinal fluid drain in skull base surgery.

OBJECTIVE: Retrospectively assess the efficacy of lumbar cerebrospinal fluid (CSF) drainage placed preoperatively in skull base operations in decreasing the incidence of postoperative CSF fistula. METHODS: A retrospective review of 150 patients undergoing a posterior fossa craniotomy from 1989 to 2000 was conducted. Patients were divided into those receiving preoperative lumbar drains and those that did not. The rates of postoperative CSF leakage were compared between the two groups. Patient data were analyzed to determine if there were other comorbidities affecting the postoperative incidence of CSF leakage such as smoking, diabetes, or hypertension. RESULTS: Between 1989 and 1994, 25/72 (35%) patients with no preoperative lumbar drain had a postoperative CSF leak. From 1995 to 2000, 9/78 (12%) patients with a preoperative lumbar drain had a CSF leak. This was a 23% decreased incidence of postoperative CSF leakage and a significant decrease in the probability (p < 0.001) of CSF leakage in patients treated with a preoperative lumbar drain. The comorbidities of diabetes, smoking, or hypertension did not increase the probability of a CSF leak (p = 0.43). CONCLUSIONS: A preoperatively placed lumbar drain can significantly lower the rate of postoperative CSF leakage after skull base surgery. The drain is a well-tolerated adjunct to dural closure and helps increase surgical exposure of the posterior fossa. The comorbidities of diabetes, smoking, or hypertension do not contribute to an increased rate of CSF leakage.dagger Lyal Leibrock M.D., F.A.C.S. is Deceased.

Decreased nasal mucosal sensitivity in older subjects.

BACKGROUND: The sensitivity of the human nasal cavity mucosa to touch is not well understood. The site of receptors and mode of action responsible for the sensation of the nasal airflow is a topic of controversy. Previous studies have suggested that the skin-lined nasal vestibule is more sensitive to airflow than the mucosa of the nasal cavity. A possible decline in nasal sensitivity to airflow in older subjects has not been studied. METHODS: The threshold of the mucosal sensitivity to jets of air was assessed in 76 subjects with healthy nasal cavities. A total of 141 nostrils were tested, 67 in younger patients and 74 in older patients. RESULTS: Statistically significant (p < 0.001) increases in thresholds were found for all points tested for older patients compared with the younger patients. In general, the more sensitive locations were in the nasal vestibule. The nasal cavity mucosa in the inferior meatus was slightly more sensitive than the middle meatus. CONCLUSION: We have measured the threshold to touch (air jet sensitivity) in nine places in each of 141 nasal cavities and determined that the variability and sensitivity of these measurements among people varies by age and the distance from the nostril. Older subjects were found to have a higher threshold for the sensation of airflow, and the nasal vestibule was found to be more sensitive than the rest of the nasal cavity mucosa with the inferior meatus slightly more sensitive then the middle meatus.