Extraordinary Speech and Language Outcomes After Auditory Brainstem Implantation: Guidance From a Case Study.

PURPOSE: Large individual differences and poor speech recognition outcomes are routinely observed in most patients who have received auditory brainstem implants (ABIs). A case report of an ABI recipient with exceptionally good speech recognition outcomes presents an opportunity to better understand the core information processing mechanisms that underlie variability and individual differences in outcomes. METHOD: A case study is reported of an adult ABI recipient (ID-006) with postlingually acquired, Neurofibromatosis Type 2 (NF2)-related hearing loss who displayed exceptional postoperative speech recognition scores. A novel battery of assessment measures was used to evaluate ID-006's auditory, cognitive, and linguistic information processing skills. RESULTS: Seventeen years following ABI activation, ID-006 scored 77.6% correct on the AzBio Sentences in quiet. On auditory processing tasks, ID-006 scored higher on tasks with meaningful sentences and much lower on tasks that relied exclusively on audibility. ID-006 also demonstrated exceptionally strong abilities on several cognitive and linguistic information processing tasks. CONCLUSIONS: Results from a novel battery of information processing tests suggest that ID-006 relies extensively on top-down predictive processing and cognitive control strategies to efficiently encode and process auditory information provided by his ABI. Results suggest that current measures of outcomes and benefits should be expanded beyond conventional speech recognition measures to include more sensitive and robust measures of speech recognition as well as neurocognitive measures such as executive function, working memory, and lexical access.

Advances in Targeted Therapy for Neurofibromatosis Type 2 (NF2)-Associated Vestibular Schwannomas.

PURPOSE OF REVIEW: Neurofibromatosis 2 (NF2) is an autosomal-dominant genetic disorder characterized by bilateral vestibular schwannomas (VS), meningiomas, ependymomas, spinal and peripheral schwannomas, optic gliomas, and juvenile cataracts. Ongoing studies provide new insight into the role of the NF2 gene and merlin in VS tumorigenesis. RECENT FINDINGS: As NF2 tumor biology becomes increasingly understood, therapeutics targeting specific molecular pathways have been developed and evaluated in preclinical and clinical studies. NF2-associated VS are a source of significant morbidity with current treatments including surgery, radiation, and observation. Currently, there are no FDA-approved medical therapies for VS, and the development of selective therapeutics is a high priority. This manuscript reviews NF2 tumor biology and current therapeutics undergoing investigation for treatment of patients with VS.

Reduction of sporadic and neurofibromatosis type 2-associated vestibular schwannoma growth in vitro and in vivo after treatment with the c-Jun N-terminal kinase inhibitor AS602801.

OBJECTIVE: Vestibular schwannomas (VSs) are benign nerve sheath tumors that result from mutation in the tumor suppressor gene NF2, with functional loss of the protein merlin. The authors have previously shown that c-Jun N-terminal kinase (JNK) is constitutively active in human VS cells and plays a central role in their survival by suppressing accumulation of mitochondrial superoxides, implicating JNK inhibitors as a potential systemic treatment for VS. Thus, the authors hypothesized that the adenosine 5'-triphosphate-competitive JNK inhibitor AS602801 would demonstrate antitumor activity in multiple VS models. METHODS: Treatment with AS602801 was tested in primary human VS cultures, human VS xenografts, and a genetic mouse model of schwannoma (Postn-Cre;Nf2flox/flox). Primary human VS cell cultures were established from freshly obtained surgical tumor specimens; treatment group media was enriched with AS602801. VS xenograft tumors were established in male athymic nude mice from freshly collected human tumor. Four weeks postimplantation, a pretreatment MRI scan was obtained, followed by 65 days of AS602801 (n = 18) or vehicle control (n = 19) treatment. Posttreatment MRI scans were used to measure final tumor volume. Tumors were then harvested. Finally, Postn-Cre;Nf2flox/flox mice were treated with AS602801 (n = 10) or a vehicle (n = 13) for 65 days. Posttreatment auditory brainstem responses were obtained. Dorsal root ganglia from Postn-Cre;Nf2flox/flox mice were then harvested. In all models, schwannoma identity was confirmed with anti-S100 staining, cell proliferation was measured with the EdU assay, and cell death was measured with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining. All protocols were approved by the local institutional review board and Institutional Animal Care and Use Committees. RESULTS: Treatment with AS602801 decreased cell proliferation and increased apoptosis in primary human VS cultures. The systemic administration of AS602801 in mice with human VS xenografts reduced tumor volume and cell proliferation. Last, the AS602801-treated Postn-Cre;Nf2flox/flox mice demonstrated decreased cell proliferation in glial cells in the dorsal root ganglia. However, AS602801 did not significantly delay hearing loss in Postn-Cre;Nf2flox/flox mice up to 3 months posttreatment. CONCLUSIONS: The data suggest that JNK inhibition with AS602801 suppresses growth of sporadic and neurofibromatosis type 2-associated VSs. As such, AS602801 is a potential systemic therapy for VS and warrants further investigation.

Speech Recognition Outcomes in Adults With Slim Straight and Slim Modiolar Cochlear Implant Electrode Arrays.

OBJECTIVE: To compare differences in audiologic outcomes between slim modiolar electrode (SME) CI532 and slim lateral wall electrode (SLW) CI522 cochlear implant recipients. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary academic hospital. METHODS: Comparison of postoperative AzBio sentence scores in quiet (percentage correct) in adult cochlear implant recipients with SME or SLW matched for preoperative AzBio sentence scores in quiet and aided and unaided pure tone average. RESULTS: Patients with SLW (n = 52) and patients with SME (n = 37) had a similar mean (SD) age (62.0 [18.2] vs 62.6 [14.6] years, respectively), mean preoperative aided pure tone average (55.9 [20.4] vs 58.1 [16.4] dB; P = .59), and mean AzBio score (percentage correct, 11.1% [13.3%] vs 8.0% [11.5%]; P = .25). At last follow-up (SLW vs SME, 9.0 [2.9] vs 9.9 [2.6] months), postoperative mean AzBio scores in quiet were not significantly different (percentage correct, 70.8% [21.3%] vs 65.6% [24.5%]; P = .29), and data log usage was similar (12.9 [4.0] vs 11.3 [4.1] hours; P = .07). In patients with preoperative AzBio <10% correct, the 6-month mean AzBio scores were significantly better with SLW than SME (percentage correct, 70.6% [22.9%] vs 53.9% [30.3%]; P = .02). The intraoperative tip rollover rate was 8% for SME and 0% for SLW. CONCLUSIONS: Cochlear implantation with SLW and SME provides comparable improvement in audiologic functioning. SME does not exhibit superior speech recognition outcomes when compared with SLW.

Brigatinib causes tumor shrinkage in both NF2-deficient meningioma and schwannoma through inhibition of multiple tyrosine kinases but not ALK.

Neurofibromatosis Type 2 (NF2) is an autosomal dominant genetic syndrome caused by mutations in the NF2 tumor suppressor gene resulting in multiple schwannomas and meningiomas. There are no FDA approved therapies for these tumors and their relentless progression results in high rates of morbidity and mortality. Through a combination of high throughput screens, preclinical in vivo modeling, and evaluation of the kinome en masse, we identified actionable drug targets and efficacious experimental therapeutics for the treatment of NF2 related schwannomas and meningiomas. These efforts identified brigatinib (ALUNBRIG®), an FDA-approved inhibitor of multiple tyrosine kinases including ALK, to be a potent inhibitor of tumor growth in established NF2 deficient xenograft meningiomas and a genetically engineered murine model of spontaneous NF2 schwannomas. Surprisingly, neither meningioma nor schwannoma cells express ALK. Instead, we demonstrate that brigatinib inhibited multiple tyrosine kinases, including EphA2, Fer and focal adhesion kinase 1 (FAK1). These data demonstrate the power of the de novo unbiased approach for drug discovery and represents a major step forward in the advancement of therapeutics for the treatment of NF2 related malignancies.

Audiologic Improvement Following MCF Approach for Spontaneous Cerebrospinal Fluid Leaks.

OBJECTIVE: To determine the audiologic improvement after middle cranial fossa (MCF) approach to repair spontaneous cerebrospinal fluid (sCSF) leaks. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: Twenty-four consecutive patients (27 ears) with temporal bone sCSF leak over a 4-year period. Patient age, sex, ethnicity, body mass index (BMI), location of CSF leak, recurrence of CSF leak, and presence of encephalocele(s) were recorded. INTERVENTION: Audiometric testing in patients undergoing MCF repair of temporal bone sCSF leak. MAIN OUTCOME MEASURES: Comparison of preoperative and postoperative pure-tone average (PTA), air-bone gap (ABG), and word recognition score (WRS) in the sCSF leak ear. RESULTS: Out of 27 ears, 55% had multiple tegmen defects and 82% had more than or equal to 1 encephaloceles. There were no recurrent CSF leaks at a median follow up of 4 months. The mean (SD) preoperative PTA and ABG were 40.58 [15.67] and 16.44 [6.93] dB, respectively. There was significant improvement in mean PTA (10.28 [8.01] dB; p < 0.001; Cohen d = 0.95) and ABG (9.31 [7.16] dB; p < 0.001; Cohen d = 0.88) after sCSF repair. Mean WRS improved (by 3.07 [6.11] %; p = 0.024; Cohen d = 0.46) from a mean preoperative WRS of 93.16 [9.34]% to a mean postoperative WRS of 96.26 [6.49]%. CONCLUSIONS: MCF approach for repair of sCSF leaks yields significant improvement in conductive hearing loss and is highly effective in management of the entire lateral skull base where multiple bony defects are often identified.

A proteasome-resistant fragment of NIK mediates oncogenic NF-κB signaling in schwannomas.

Schwannomas are common, highly morbid and medically untreatable tumors that can arise in patients with germ line as well as somatic mutations in neurofibromatosis type 2 (NF2). These mutations most commonly result in the loss of function of the NF2-encoded protein, Merlin. Little is known about how Merlin functions endogenously as a tumor suppressor and how its loss leads to oncogenic transformation in Schwann cells (SCs). Here, we identify nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-inducing kinase (NIK) as a potential drug target driving NF-κB signaling and Merlin-deficient schwannoma genesis. Using a genomic approach to profile aberrant tumor signaling pathways, we describe multiple upregulated NF-κB signaling elements in human and murine schwannomas, leading us to identify a caspase-cleaved, proteasome-resistant NIK kinase domain fragment that amplifies pathogenic NF-κB signaling. Lentiviral-mediated transduction of this NIK fragment into normal SCs promotes proliferation, survival, and adhesion while inducing schwannoma formation in a novel in vivo orthotopic transplant model. Furthermore, we describe an NF-κB-potentiated hepatocyte growth factor (HGF) to MET proto-oncogene receptor tyrosine kinase (c-Met) autocrine feed-forward loop promoting SC proliferation. These innovative studies identify a novel signaling axis underlying schwannoma formation, revealing new and potentially druggable schwannoma vulnerabilities with future therapeutic potential.

Prevalence of Obstructive Sleep Apnea (OSA) in Spontaneous Cerebrospinal Fluid (CSF) Leaks: A Prospective Cohort Study.

OBJECTIVE: To determine the prevalence of obstructive sleep apnea (OSA) in a prospective cohort of patients with spontaneous CSF (sCSF) leaks of the temporal bone. STUDY DESIGN: Prospective cohort study. SETTING: Tertiary referral center. PATIENTS: Consecutive sCSF leak patients (21) over a 3-year period. Four patients presented with a history of OSA and 17 patients were prospectively offered polysomnogram (PSG) testing during the initial clinic encounter. INTERVENTION: Level I PSG. MAIN OUTCOME MEASURES: Patient characteristics (age, sex, body mass index), apnea hypopnea index (AHI), presence of snoring, and presence of hypoxia (oxygen saturation <88% for >5 min). OSA was defined as mild (AHI ≥5 and <15/h), moderate (AHI ≥15 and <30/h), and severe (AHI ≥30/h). RESULTS: The prevalence of OSA in sCSF leak patients is 83.3%. PSG studies were performed on 18 of the 21 patients. There were 15 women and 6 men with an average age (standard deviation) of 56.3 (11.2) years and an average body mass index of 35.3 (7.7) kg/m. Objectively, the AHI ranged from mild to severe (range = 5.7-92, median = 19.8). Snoring was present in 61% of patients and hypoxia was present in 39% of patients. sCSF leak patients with OSA were significantly older than sCSF leak patients without OSA (56.7 [8.3] versus 42.7 [14.5] yr, p = 0.03). CONCLUSIONS: OSA is highly prevalent among patients with sCSF leaks. All patients with sCSF leaks should undergo formal PSG testing. Future studies are needed to determine the role of OSA in the development of sCSF leaks.

Traditional and systems biology based drug discovery for the rare tumor syndrome neurofibromatosis type 2.

Neurofibromatosis 2 (NF2) is a rare tumor suppressor syndrome that manifests with multiple schwannomas and meningiomas. There are no effective drug therapies for these benign tumors and conventional therapies have limited efficacy. Various model systems have been created and several drug targets have been implicated in NF2-driven tumorigenesis based on known effects of the absence of merlin, the product of the NF2 gene. We tested priority compounds based on known biology with traditional dose-concentration studies in meningioma and schwann cell systems. Concurrently, we studied functional kinome and gene expression in these cells pre- and post-treatment to determine merlin deficient molecular phenotypes. Cell viability results showed that three agents (GSK2126458, Panobinostat, CUDC-907) had the greatest activity across schwannoma and meningioma cell systems, but merlin status did not significantly influence response. In vivo, drug effect was tumor specific with meningioma, but not schwannoma, showing response to GSK2126458 and Panobinostat. In culture, changes in both the transcriptome and kinome in response to treatment clustered predominantly based on tumor type. However, there were differences in both gene expression and functional kinome at baseline between meningioma and schwannoma cell systems that may form the basis for future selective therapies. This work has created an openly accessible resource (www.synapse.org/SynodosNF2) of fully characterized isogenic schwannoma and meningioma cell systems as well as a rich data source of kinome and transcriptome data from these assay systems before and after treatment that enables single and combination drug discovery based on molecular phenotype.

Chemopreventative celecoxib fails to prevent schwannoma formation or sensorineural hearing loss in genetically engineered murine model of neurofibromatosis type 2.

Mutations in the tumor suppressor gene NF2 lead to Neurofibromatosis type 2 (NF2), a tumor predisposition syndrome characterized by the development of schwannomas, including bilateral vestibular schwannomas with complete penetrance. Recent work has implicated the importance of COX-2 in schwannoma growth. Using a genetically engineered murine model of NF2, we demonstrate that selective inhibition of COX-2 with celecoxib fails to prevent the spontaneous development of schwannomas or sensorineural hearing loss in vivo, despite elevated expression levels of COX-2 in Nf2-deficient tumor tissue. These results suggest that COX-2 is nonessential to schwannomagenesis and that the proposed tumor suppressive effects of NSAIDs on schwannomas may occur through COX-2 independent mechanisms.

Outpatient management of cholesteatoma with canal wall reconstruction tympanomastoidectomy.

Objectives: The postoperative wound infection rate for canal wall reconstruction (CWR) tympanomastoidectomy with mastoid obliteration in the treatment of chronic otitis media with cholesteatoma has been reported to be 3.6%. Postoperative administration of 24-48 hours of intravenous antibiotics has been recommended. We aim to determine the infection rate of CWR with postoperative outpatient oral antibiotics. Study Design: Institutional review board-approved retrospective case review. Setting: Tertiary referral center. Patients: Retrospective review of consecutive patients who underwent CWR tympanomastoidectomy with mastoid obliteration at a single institution from 2014 to 2016. Main Outcome Measure: Patient characteristics (age, sex) were calculated. Rate of postoperative complications and infections within 1 month of surgery were calculated. Comparison to previous published infection rates with postoperative intravenous antibiotics. Results: 51 patients underwent CWR followed by outpatient oral antibiotics with a mean age of 25.9 years (16 patients were less than 10 years old). There were no postoperative wound infections. Outpatient antibiotics showed non-inferiority to IV antibiotic historic controls (0% vs. 3.6%; 95% confidence interval [CI], 0-6.09%; p = 0.03). One patient had small postoperative wound dehiscence with CSF leak that was managed conservatively. One patient developed Clostridium difficile colitis on postoperative day 2. Conclusions: The infection rate after CWR tympanomastoidectomy with use of outpatient antibiotics is low and is non-inferior to a historic cohort treated with inpatient intravenous antibiotics. A larger randomized controlled trial is warranted. Level of Evidence: 4.

A murine model of neurofibromatosis type 2 that accurately phenocopies human schwannoma formation.

Neurofibromatosis type 2 (NF2) is an autosomal dominant genetic disorder resulting from germline mutations in the NF2 gene. Bilateral vestibular schwannomas, tumors on cranial nerve VIII, are pathognomonic for NF2 disease. Furthermore, schwannomas also commonly develop in other cranial nerves, dorsal root ganglia and peripheral nerves. These tumors are a major cause of morbidity and mortality, and medical therapies to treat them are limited. Animal models that accurately recapitulate the full anatomical spectrum of human NF2-related schwannomas, including the characteristic functional deficits in hearing and balance associated with cranial nerve VIII tumors, would allow systematic evaluation of experimental therapeutics prior to clinical use. Here, we present a genetically engineered NF2 mouse model generated through excision of the Nf2 gene driven by Cre expression under control of a tissue-restricted 3.9kbPeriostin promoter element. By 10 months of age, 100% of Postn-Cre; Nf2(flox/flox) mice develop spinal, peripheral and cranial nerve tumors histologically identical to human schwannomas. In addition, the development of cranial nerve VIII tumors correlates with functional impairments in hearing and balance, as measured by auditory brainstem response and vestibular testing. Overall, the Postn-Cre; Nf2(flox/flox) tumor model provides a novel tool for future mechanistic and therapeutic studies of NF2-associated schwannomas.

AR42, a novel histone deacetylase inhibitor, as a potential therapy for vestibular schwannomas and meningiomas.

Neurofibromatosis type 2 (NF2) is an autosomal-dominant disease that results in the formation of bilateral vestibular schwannomas (VSs) and multiple meningiomas. Treatment options for NF2-associated tumors are limited, and to date, no medical therapies are FDA approved. The ideal chemotherapeutic agent would inhibit both VS and meningiomas simultaneously. The objectives of this study are (1) to test the efficacy of AR42, a novel histone deacetylase inhibitor, to inhibit VS and meningioma growth and (2) to investigate this drug's mechanisms of action. Primary cultures of human VS and meningioma cells were established. Nf2-deficient mouse schwannoma and benign human meningioma Ben-Men-1 cells were also cultured. Cells were treated with AR42, and the drug's effects on proliferation and the cell cycle were analyzed using a methanethiosulfonate assay and flow cytometry, respectively. Human phospho-kinase arrays and Western blots were used to evaluate the effects of AR42 on intracellular signaling. The in vivo efficacy of AR42 was investigated using schwannoma xenografts. Tumor volumes were quantified using high-field, volumetric MRI, and molecular target analysis was performed using immunohistochemistry. AR42 inhibited the growth of primary human VS and Nf2-deficient mouse schwannoma cells with a half maximal inhibitory concentration (IC(50)) of 500 nM and 250-350 nM, respectively. AR42 also inhibited primary meningioma cells and the benign meningioma cell line, Ben-Men-1, with IC(50) values of 1.5 µM and 1.0 µM, respectively. AR42 treatment induced cell-cycle arrest at G(2) and apoptosis in both VS and meningioma cells. Also, AR42 exposure decreased phosphorylated Akt in schwannoma and meningioma cells. In vivo treatment with AR42 inhibited the growth of schwannoma xenografts, induced apoptosis, and decreased Akt activation. The potent growth inhibitory activity of AR42 in schwannoma and meningioma cells suggests that AR42 should be further evaluated as a potential treatment for NF2-associated tumors.

Fatal case of tumor-associated hemorrhage in a large vestibular schwannoma.

Vestibular schwannomas are benign neoplasms that arise from Schwann cells of the eighth cranial nerve. Most manifest clinically with tinnitus, unilateral sensorineural hearing loss, and dysequilibrium secondary to compression of the vestibulocochlear nerve; major adverse events such as intratumoral hemorrhage causing acute neurologic deterioration are rare. We report the case of a 69-year-old man with a large vestibular schwannoma who required anticoagulation for several medical comorbidities. The patient began having progressively worsening neurologic symptoms, including facial nerve paralysis and dysequilibrium, which confined him to a wheelchair. After presentation, the patient was admitted to the hospital. Several days after alteration of his anticoagulation therapy in preparation for surgery, he developed intracranial hemorrhage. Attempts were made to stabilize the patient, including posterior fossa craniectomy and evacuation of hematoma; however, the intracranial hemorrhage ultimately resulted in a fatal outcome. During this procedure, a biopsy specimen was obtained, showing benign vestibular schwannoma. The literature for intratumoral hemorrhage into vestibular schwannoma and the pathologic findings in our case are reviewed.

Regulation of smooth muscle-specific gene expression by homeodomain proteins, Hoxa10 and Hoxb8.

Smooth muscle cells arise from different populations of precursor cells during embryonic development. The mechanisms that specify the smooth muscle cell phenotype in each of these populations of cells are largely unknown. In many tissues and organs, homeodomain transcription factors play a key role in directing cell specification. However, little is known about how these proteins regulate smooth muscle differentiation. Using degenerate reverse transcription-PCR coupled to cDNA library screening we identified two homeodomain proteins, Hoxa10 and Hoxb8, which are expressed in adult mouse smooth muscle tissues. All three of the previously described transcripts of the Hoxa10 gene, Hoxa10-1, Hoxa10-2, and Hoxa10-3, were identified. Hoxa10-1 directly activated the smooth muscle-specific telokin promoter but did not activate the SM22alpha, smooth muscle alpha-actin, or smooth muscle myosin heavy chain promoters. Small interfering RNA-mediated knock-down of Hoxa10-1 demonstrated that Hoxa10-1 is required for high levels of telokin expression in smooth muscle cells from uterus and colon. On the other hand, Hoxb8 inhibited the activity of the telokin, SM22alpha, and smooth muscle alpha-actin promoters. Cotransfection of Hoxa10-1 together with Hoxa10-2 or Hoxb8 suggested that Hoxa10-2 and Hoxb8 act as competitive inhibitors of Hoxa10-1. Results from gel mobility shift assays demonstrated that Hoxa10-1, Hoxa10-2, and Hoxb8 bind directly to multiple sites in the telokin promoter. Mutational analysis of telokin promoter reporter genes demonstrated that the three homeodomain protein binding sites located between -80 and -75, +2 and +6, and +14 and +17 were required for maximal promoter activation by Hoxa10-1 and maximal inhibition by Hoxb8. Together these data demonstrate that the genes encoding smooth muscle-restricted proteins are direct transcriptional targets of clustered homeodomain proteins and that different homeodomain proteins have distinct effects on the promoters of these genes.