Khandalavala, Karl R.

OBJECTIVE It is uncertain which cochlear dose parameters significantly impact hearing after stereotactic radiosurgery (SRS) for sporadic vestibular schwannoma (VS). The objective of this study was to determine the impact of cochlear dose parameters on hearing outcomes for patients with serviceable hearing (SH). METHODS This was a historical cohort study performed at a single tertiary center that included patients with sporadic VS and SH who underwent single-session Gamma Knife radiosurgery treatment from 2007 to 2022. Associations of cochlear dose parameters with time to non-SH and rates of change in pure-tone average (PTA) and word recognition score (WRS) following SRS were assessed. RESULTS A total of 205 patients with SH underwent SRS for a sporadic VS. At SRS, 54 (26%) tumors were confined to the internal auditory canal and 151 (74%) extended into the cerebellopontine angle. At 2, 5, and 10 years following SRS, 62%, 37%, and 15% of patients maintained SH, respectively. The median time to non-SH was 1.8 years. The median rates of change in PTA and WRS were 6.0 dB of hearing loss per year and −6.5% per year, respectively. In a multivariable analysis, each 1-Gy increase in minimum cochlear dose was significantly associated with time to non-SH (HR 1.5, 95% CI 1.2–1.9), rate of change in PTA decibel hearing loss per year (parameter estimate [PE] 3.4, 95% CI 0.6–6.2), and rate of change in WRS percentage per year (PE −6.4, 95% CI −11.2 to −1.5). The associations of each 1-Gy increase in mean cochlear dose with hearing outcomes were only significant among patients with class B hearing (time to non-SH HR 1.3, 95% CI 1.1–1.6; rate of change in PTA PE 3.6, 95% CI 1.2–5.9; and rate of change in WRS PE −5.7, 95% CI −9.7 to −1.7). CONCLUSIONS The minimum cochlear dose impacts hearing outcomes after SRS for VS and should be considered in radiosurgical treatment planning. In this cohort, the mean cochlear dose was only associated with hearing outcomes in the subgroup of patients with class B hearing at SRS.

Objective To report the feasibility and potential utility of monitoring acoustic hearing on awake patients using intraoperative behavioral responses to threshold and suprathreshold stimuli while undergoing cochlear implantation (CI) under local anesthesia, without any form of sedation. Study Design Retrospective review of the first five cases performed by one surgeon. Setting Tertiary care academic medical center. Patients Adult patients with residual acoustic hearing undergoing CI. Interventions CI under local anesthesia, without any form of sedation. Main Outcome Measures Procedural tolerance, reliability of intraoperative pure tone threshold and suprathreshold audiometry, and correlation of intraoperative findings with early postoperative residual hearing. Results Five ears in four patients underwent CI, including three males and one female, with a median age of 61 years. Intraoperatively, patients reported reliable behavioral responses to pure tone threshold and suprathreshold stimuli and provided real-time feedback on perceived stimulus change to the surgeon just prior to, during, and immediately following electrode insertion. All patients were able to complete the operation under local anesthesia. During electrode insertion, three cases reported no change and two cases reported diminished stimulus perception that reversed with limited electrode pull back near terminal insertion. Immediate postoperative audiograms demonstrated preservation of bone conduction thresholds within 10 dB of their preoperative baseline for all cases, suggesting hearing preservation. Three-month postoperative AzBio in quiet scores were available for two patients, measuring 45% and 94%, respectively. Conclusions This report describes the feasibility of intraoperative behavioral audiometry during CI under local anesthesia, using patient feedback during electrode insertion to optimize hearing preservation surgery. Akin to other surgical subspecialties that use real-time patient feedback where objective intraoperative measures of neurofunction are imperfect, we demonstrate feasibility and potential utility of live acoustic monitoring during CI.

AbstractObjectiveStereotactic radiosurgery (SRS) is increasingly used for small‐to‐medium‐sized sporadic vestibular schwannoma (VS) and is associated with good tumor control and low‐risk of adverse radiation‐associated events. The exact mechanism of VS tumor control is unknown but may relate to microvascular hyalinization and resultant tumoral ischemia. This study examined associations of microvascular risk factors with outcomes following SRS.DesignHistorical cohort of patients who underwent SRS for sporadic VS from 2000 to 2022.SettingTertiary academic center.MethodsAssociations of microvascular risk factors with tumor control and complications were evaluated using Cox proportional hazards regression.ResultsIn total 749 patients were studied, 31% with a history of smoking, 38% obesity, 19% hypertension, 8% diabetes, 3% peripheral vascular disease, and 2% history of coronary bypass. Regarding tumor control, no factor was associated with salvage treatment following SRS (n = 42). Hypertension (hazard ratio [HR] 2.81; P = .02) and coronary bypass (HR 6.91; P = .002) were significantly associated with developing facial nerve paresis (n = 22). No significant associations with new facial spasms (n = 53) were identified. Lastly, 191 of 294 patients with serviceable hearing at SRS progressed to nonserviceable hearing at a median 2.0 years (interquartile range: 1.0‐5.0). After multivariable adjustment for age and ipsilateral hearing status, the HR for the association of smoking history with time to nonserviceable hearing was 1.46 (95% confidence interval 1.04‐2.04; P = .03).ConclusionWe demonstrate that hypertension and history of coronary bypass may be associated with development of facial nerve weakness, while smoking may be associated with accelerated hearing loss in patients undergoing SRS for sporadic VS. These data may help guide patient counseling and inform decision‐making regarding treatment.

Objective To describe outcomes of patients with sporadic vestibular schwannoma (VS) who underwent repeat stereotactic radiosurgery (SRS) after primary SRS failure. Study Design Multi-institutional historical cohort study. Setting Five tertiary care referral centers. Patients Adults ≥18 years old with sporadic VS. Intervention Primary and repeat treatment with SRS. Main Outcome Measure Microsurgery-free survival after repeat SRS. Results Across institutions, 32 patients underwent repeat SRS after primary SRS. Most patients (74%) had tumors with cerebellopontine angle extension at primary SRS (median size, 13.5 mm [interquartile range, 7.5–18.8] mm). After primary SRS, patients underwent repeat SRS at a median of 4.8 years (interquartile range, 3.2–5.7 yr). For treatment modality, 30 (94%) patients received gamma knife for primary treatment and 31 (97%) patients received gamma knife as their repeat treatment. Median tumor volume increased from 0.970 cm3 at primary SRS to 2.200 cm3 at repeat SRS. Facial nerve function worsened in two patients after primary SRS and in two patients after repeat SRS. There were no instances of intracranial complications after repeat SRS. Microsurgery-free survival rates (95% confidence interval; number still at risk) at 1, 3, and 5 years after repeat SRS were 97% (90–100%, 24), 84% (71–100%, 13), and 68% (48–96%, 6), respectively. There was one occurrence of malignancy diagnosed after repeat radiosurgery. Conclusion Overall, repeat SRS for sporadic VS has comparable risk profile, but lower rates of tumor control, compared with primary SRS.

Objective To examine patient preference after stapedotomy versus cochlear implantation in a unique case of a patient with symmetrical profound mixed hearing loss and similar postoperative speech perception improvement. Patients An adult patient with bilateral symmetrical far advanced otosclerosis, with profound mixed hearing loss. Intervention Stapedotomy in the left ear, cochlear implantation in the right ear. Main Outcome Measure Performance on behavioral audiometry, and subjective report of hearing and intervention preference. Results A patient successfully underwent left stapedotomy and subsequent cochlear implantation on the right side, per patient preference. Preoperative audiometric characteristics were similar between ears (pure-tone average [PTA] [R: 114; L: 113 dB]; word recognition score [WRS]: 22%). Postprocedural audiometry demonstrated significant improvement after stapedotomy (PTA: 59 dB, WRS: 75%) and from cochlear implant (PTA: 20 dB, WRS: 60%). The patient subjectively reported a preference for the cochlear implant ear despite having substantial gains from stapedotomy. A nuanced discussion highlighting potentially overlooked benefits of cochlear implants in far advanced otosclerosis is conducted. Conclusion In comparison with stapedotomy and hearing aids, cochlear implantation generally permits greater access to sound among patients with far advanced otosclerosis. Though the cochlear implant literature mainly focuses on speech perception outcomes, an underappreciated benefit of cochlear implantation is the high likelihood of achieving “normal” sound levels across the audiogram.

ImportanceManagement of sporadic vestibular schwannoma with radiosurgery is becoming increasingly common globally; however, limited data currently characterize patient outcomes in the setting of microsurgical salvage for radiosurgical failure.ObjectiveTo describe the clinical outcomes of salvage microsurgery following failed primary stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT) among patients with sporadic vestibular schwannoma.Design, Setting, and ParticipantsThis was a cohort study of adults (≥18 years old) with sporadic vestibular schwannoma who underwent salvage microsurgery following failed primary SRS/FSRT in 7 vestibular schwannoma treatment centers across the US and Norway. Data collection was performed between July 2022 and January 2023, with data analysis performed between January and July 2023.ExposureSalvage microsurgical tumor resection.Main Outcomes and MeasuresComposite outcome of undergoing less than gross total resection (GTR) or experiencing long-term facial paresis.ResultsAmong 126 patients, the median (IQR) age at time of salvage microsurgery was 62 (53-70) years, 69 (55%) were female, and 113 of 117 (97%) had tumors that extended into the cerebellopontine angle at time of salvage. Of 125 patients, 96 (76%) underwent primary gamma knife SRS, while 24 (19%) underwent linear accelerator-based SRS; the remaining patients underwent FSRT using other modalities. Postoperative cerebrospinal fluid leak was seen in 15 of 126 patients (12%), hydrocephalus in 8 (6%), symptomatic stroke in 7 (6%), and meningitis in 2 (2%). Each 1-mm increase in cerebellopontine angle tumor size was associated with a 13% increased likelihood of foregoing GTR (64 of 102 patients [63%]) or long-term postoperative House-Brackmann grade higher than I (48 of 102 patients [47%]) (odds ratio, 1.13; 95% CI, 1.04-1.23). Following salvage microsurgery, tumor growth–free survival rates at 1, 3, and 5 years were 97% (95% CI, 94%-100%), 93% (95% CI, 87%-99%), and 91% (95% CI, 84%-98%), respectively.ConclusionsIn this cohort study, more than half of patients who received salvage microsurgery following primary SRS/FSRT underwent less than GTR or experienced some degree of facial paresis long term. These data suggest that the cumulative risk of developing facial paresis following primary SRS/FSRT by the end of the patient’s journey with treatment approximates 2.5% to 7.5% when using published primary SRS/FSRT long-term tumor control rates.

Objective: to review evidence on the efficacy of auditory training in adult cochlear implant recipients. Data Sources: PRISMA guidelines for a systematic review of the literature were followed. PubMed, Scopus, and CINAHL databases were queried on 29 June 2023 for terms involving cochlear implantation and auditory training. Studies were limited to the English language and adult patient populations. Study Selection: Three authors independently reviewed publications for inclusion in the review based on a priori inclusion and exclusion criteria. Inclusion criteria encompassed adult cochlear implant populations, an analysis of clinician- or patient-directed auditory training, and an analysis of one or more measures of speech recognition and/or patient-reported outcome. Exclusion criteria included studies with only pediatric implant populations, music or localization training in isolation, and single-sample case studies. Data Extraction: The data were collected regarding study design, patient population, auditory training modality, auditory training timing, speech outcomes, and data on the durability of outcomes. A quality assessment of the literature was performed using a quality metric adapted from the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group guidelines. Data Synthesis and Meta-Analysis: Data were qualitatively summarized for 23 studies. All but four studies demonstrated significant improvement in at least one measured or patient-reported outcome measure with training. For 11 studies with sufficient data reporting, pre-intervention and post-intervention pooled means of different outcome measures were compared for 132 patients using meta-analysis. Patient-direct training was associated with significant improvement in vowel-phoneme recognition and speech recognition in noise (p < 0.05 and p < 0.001, respectively), and clinician-directed training showed significant improvement in sentence recognition in noise (p < 0.001). Conclusions: The literature on auditory training for adult cochlear implant recipients is limited and heterogeneous, including a small number of studies with limited levels of evidence and external validity. However, the current evidence suggests that auditory training can improve speech recognition in adult cochlear implant recipients.

Objective The treatment paradigm of vestibular schwannoma (VS) focuses on preservation of neurologic function, with small tumors increasingly managed with active surveillance. Often, tumor size and hearing outcomes are poorly correlated. The aim of the current work was to describe the natural history of hearing among patients with nongrowing VS during observational management. Study Design Historical cohort study. Patients Adults with sporadic VS. Intervention Wait-and-scan management. Main Outcome Measure Maintenance of serviceable hearing (SH) after diagnosis. Results Among 228 patients with nongrowing VS, 157 patients had SH at diagnosis. Rates of maintaining SH (95% CI; number still at risk) at 1, 3, and 5 years after diagnosis were 94% (89–98; 118), 81% (74–89; 65), and 78% (71–87; 42), respectively. Poorer hearing at diagnosis (hazard ratio [HR] per 10 dB hearing level increase in pure-tone average of 2.51, p < 0.001; HR per 10% decrease in word recognition score of 1.70, p = 0.001) was associated with increased likelihood of developing non-SH during observation. When controlling for baseline hearing status, tumors measuring 5 mm or greater in the internal auditory canal or with cerebellopontine angle extension were associated with significantly increased risk of developing non-SH (HR, 4.87; p = 0.03). At 5 years after diagnosis, 95% of patients with nongrowing intracanalicular VS measuring less than 5 mm maintained SH. Conclusions Hearing worsens during periods of nongrowth in sporadic VS. Patients with small (<5 mm) intracanalicular tumors demonstrate robust maintenance of SH over time, reinforcing the consideration of initial observation in this patient subset.

AbstractObjectiveTo investigate the association between standard pure tone and speech audiometry with neuroimaging characteristics reflective of aging and dementia in older adults.Study DesignProspective population‐based study.SettingSingle tertiary care referral center.MethodsParticipants from the Mayo Clinic Study of aging 60 years old or older with normal cognition or mild cognitive impairment, baseline neuroimaging, and a behavioral audiogram associated with neuroimaging were eligible for study. Imaging modalities included structural MRI (sMRI) and fluid‐attenuated inversion recovery MRI (FLAIR‐MRI; N = 605), diffusion tensor imaging MRI (DTI‐MRI; N = 444), and fluorodeoxyglucose‐positron emission tomography (FDG‐PET; N = 413). Multivariable logistic and linear regression models were used to evaluate associations with neuroimaging outcomes.ResultsMean (SD) pure tone average (PTA) was 33 (15) dB HL and mean (SD) word recognition score (WRS) was 91% (14). There were no significant associations between audiometric performance and cortical thinning assessed by sMRI. Each 10‐dB increase in PTA was associated with increased likelihood of abnormal white‐matter hyperintensity (WMH) from FLAIR‐MRI (odds ratio 1.26, P = .02). From DTI‐MRI, participants with <100% WRSs had significantly lower fractional anisotropy in the genu of the corpus callosum (parameter estimate [PE] −0.012, P = .008) compared to those with perfect WRSs. From FDG‐PET, each 10% decrease in WRSs was associated with decreased uptake in the anterior cingulate cortex (PE −0.013, P = .001).ConclusionPoorer audiometric performance was not significantly associated with cortical thinning but was associated with white matter damage relevant to cerebrovascular disease (increased abnormal WMH, decreased corpus callosum diffusion). These neuroimaging results suggest a pathophysiologic link between hearing loss and cerebrovascular disease.

Background: No standard schedule for cochlear implant (CI) programming has been developed, and common practices may have CI recipients seen in excess of what is necessary. The objective of this study was to review evidence for a de-escalated, evidence-based schedule for adult CI programming. Methods: Systematic review was undertaken in March 2023 of PubMed, Scopus, and CINAHL databases using the Preferred Reporting Items for Systemic Reviews and Meta-analyses (PRISMA) guidelines. Studies were included if (1) they evaluated an evidence-based programming/follow-up schedule in new adult CI patients or (2) they evaluated programming or outcomes in a longitudinal fashion such that they could inform CI follow-up strategies. Level of evidence was evaluated using the LEGEND evidence assessment tool. Results: Our review identified 940 studies. After screening with a priori inclusion criteria, 18 studies were ultimately included in this review. Of these, 2 demonstrated feasibility of de-escalated approaches to new adult CI programming. The remainder presented longitudinal speech and programming parameter data that demonstrated relative stability of both categories by 3 to 6 months post-activation. Conclusions: Overall, there is a paucity of literature evaluating any form of evidence-based CI programming or follow-up. Most applicable data derive from longitudinal outcomes featured in studies of other CI features, with only a handful of studies directly evaluating CI programming strategies over time. However, stability in outcomes and programming detailed in the available data supports consideration of a de-escalated programming paradigm that could primarily limit programming to the very early post-activation period (before 3 to 6 months) to enhance patient care and reduce operational strains on cochlear implant programs.