Faculty Bibliography

Sensorimotor reflex circuits engage distinct neuronal subtypes, defined by precise connectivity, to transform sensation into compensatory behavior. Whether and how motor neuron populations specify the subtype fate and/or sensory connectivity of their pre-motor partners remains controversial. Here, we discovered that motor neurons are dispensable for proper connectivity in the vestibular reflex circuit that stabilizes gaze. We first measured activity following vestibular sensation in pre-motor projection neurons after constitutive loss of their extraocular motor neuron partners. We observed normal responses and topography indicative of unchanged functional connectivity between sensory neurons and projection neurons. Next, we show that projection neurons remain anatomically and molecularly poised to connect appropriately with their downstream partners. Lastly, we show that the transcriptional signatures that typify projection neurons develop independently of motor partners. Our findings comprehensively overturn a long-standing model: that connectivity in the circuit for gaze stabilization is retrogradely determined by motor partner-derived signals. By defining the contribution of motor neurons to specification of an archetypal sensorimotor circuit, our work speaks to comparable processes in the spinal cord and advances our understanding of principles of neural development.

Although cochlear implants (CI) successfully replace the sense of hearing, they do not restore natural hearing. Still, CI users adapt to this novel signal, reaching meaningful levels of speech recognition in clinical tests that focus on repetition of words and short sentences. However, many patients who score above average in clinical speech perception tests complain that everyday speech interactions are both difficult and cognitively draining. In part this difficulty may be due to the naturally rapid pace of everyday discourse. We report a study in which 12 CI users aged 23 to 77, recalled multi-sentence discourse presented without interruption, or in the condition of interest, when passages were paused at major linguistic boundaries, with participants given control of when to initiate the next segment. Comprehension of the discourse structure was based on a formalized representational system that organizes discourse elements hierarchically to index the relative importance of different elements to the overall understanding of the discourse. Results showed (a) better recall when CI users were allowed to control the discourse pace, (b) an overall effect of aging, with older CI users recalling discourse less accurately, (c) better recall for passages with higher average inter-word predictability, (d) a "semantic hierarchy effect" reflected by better recall of main ideas versus minor details, (e) an attenuation of the semantic hierarchy effect for low predictability passages. Results underscore the benefits of extra processing time in addressing CI listening challenges and highlight the limited ecological validity of single-word or single-sentence speech recognition tests.

The sensation of gravity anchors our perception of the environment and is important for navigation. However, the neural circuits that transform gravity into commands for navigation are undefined. We first determined that larval zebrafish (Danio rerio) navigate vertically by maintaining a consistent heading across a series of upward climb or downward dive bouts. Gravity-blind mutant fish swim with more variable heading and excessive veering, leading to less effective vertical navigation. After targeted photoablation of ascending vestibular neurons and spinal projecting midbrain neurons, but not vestibulospinal neurons, vertical navigation was impaired. These data define a sensorimotor circuit that uses evolutionarily conserved brainstem architecture to transform gravitational signals into persistent heading for vertical navigation. The work lays a foundation to understand how vestibular inputs allow animals to move effectively through their environment.

BACKGROUND AND OBJECTIVES/OBJECTIVE:The management of World Health Organization (WHO) grade 2 meningiomas is complicated by their diverse clinical behaviors. Stereotactic radiosurgery (SRS) can be an effective management option. Literature on SRS dose selection is limited but suggests that a higher dose is better for tumor control. We characterize the predictors of post-SRS outcomes that can help guide planning and management. METHODS:We reviewed a cohort of consecutive patients with pathologically-proven WHO grade 2 meningiomas who underwent SRS at a single institution between 2011 and 2023. RESULTS:Ninety-nine patients (median age 62 years) underwent SRS, 11 of whom received hypofractionated SRS in 5 fractions. Twenty-two patients had received previous irradiation. The median follow-up was 49 months. The median overall survival was 119 months (95% CI 92-NA) with estimated 5- and 10-year survival of 83% and 27%, respectively. The median progression-free survival (PFS) was 40 months (95% CI 32-62), with 3- and 5-year rates at 54% and 35%, respectively. The median locomarginal PFS was 63 months (95% CI 51.8-NA) with 3- and 5-year rates at 65% and 52%. Nine (9%) patients experienced adverse events, 2 Common Terminology Criteria for Adverse Events grade 3 and 7 grade 2, consisting of worsening neurologic deficit from edema. In the single-session cohort, Ki-67 significantly predicted both overall survival and intracranial PFS. Tumors with Ki-67 >10% had 2.17 times the risk of locomarginal progression compared with Ki-67 ≤10% (P = .018) adjusting for covariates. Sex, prescription dose, tumor volume, and location also predicted tumor control. In tumors with Ki-67 >10%, margin dose ≥14 Gy was associated with significantly better tumor control but not for tumors with Ki-67 ≤10%. CONCLUSION/CONCLUSIONS:The management of WHO grade 2 meningiomas requires a multimodality approach. This study demonstrates the value of a targeted SRS approach in patients with limited disease and further establishes predictive biomarkers that can guide planning through a personalized approach.

BACKGROUND:Radioactive iodine therapy (RAI) is a frequently chosen therapy for Graves' disease. The aim of this study was to determine whether RAI for Graves' disease increases the risk of thyroid malignancy. METHODS:A retrospective analysis was performed of all Graves' disease patients who underwent thyroidectomy at a single institution between 2013 and 2022. Comparative analyses were performed with cohorts based on RAI therapy as the primary grouping variable. RESULTS:413 patients were identified, of which 38 received RAI prior to surgery. RAI treated patients were more likely to undergo surgery for known malignancy or indeterminate nodules. RAI patients were also more likely to have malignancies larger than 1 ​cm. Among RAI treated patients, those who developed malignancy were older at the time of Graves' diagnosis and received early RAI therapy. CONCLUSIONS:Use of RAI for treatment of Graves' disease increases the progression of thyroid carcinoma, but not the prevalence. Older age and early RAI therapy may be risk factors for malignancy in RAI treated patients.

OBJECTIVE:Vocal tremor (VT) poses treatment challenges due to uncertain pathophysiology. VT is typically classified into two phenotypes: isolated vocal tremor (iVT) and essential tremor-related voice tremor (ETvt). The impact of phenotypes on upper aerodigestive tract physiology during swallowing remains unclear. Qualitative and quantitative measures were employed to characterize tremor phenotypes and investigate the effects on swallowing physiology. METHODS:Eleven ETvt participants (1 Male, 10 Female; x̄ age = 74) and 8 iVT participants (1 Male, 7 Female; x̄ age = 71) swallowed 20 mL boluses in cued and uncued conditions under standardized fluoroscopic visualization. Sustained/a/productions were captured to assess the rate and extent of fundamental frequency (F0) modulation. Penetration and Aspiration Scale (PAS) scores were obtained and swallowing biomechanics were captured using Swallowtail™ software. Participants also completed the Swallowing Quality of Life (SWAL-QOL) questionnaire. RESULTS:Hypopharyngeal transit was faster in both VT phenotypes compared with Swallowtail™ normative reference data. Total pharyngeal transit times, however, were only faster in patients with iVT, relative to reference data. No significant differences were observed on the SWAL-QOL or PAS between tremor phenotypes. SWAL-QOL scores revealed that these patients rarely reported dysphagia symptoms. CONCLUSIONS:Subtle differences in swallowing patterns were observed across VT phenotypes, possibly related to adaptive mechanisms resulting in quicker pharyngeal bolus transit. Most patients did not report swallowing issues or dysphagia symptoms. This study is foundational for larger studies on this challenging population. LEVEL OF EVIDENCE/METHODS:4 Laryngoscope, 134:4599-4603, 2024.

Perception can be refined by experience, up to certain limits. It is unclear whether perceptual limits are absolute or could be partially overcome via enhanced neuromodulation and/or plasticity. Recent studies suggest that peripheral nerve stimulation, specifically vagus nerve stimulation (VNS), can alter neural activity and augment experience-dependent plasticity, although little is known about central mechanisms recruited by VNS. Here we developed an auditory discrimination task for mice implanted with a VNS electrode. VNS applied during behavior gradually improved discrimination abilities beyond the level achieved by training alone. Two-photon imaging revealed VNS induced changes to auditory cortical responses and activated cortically projecting cholinergic axons. Anatomical and optogenetic experiments indicated that VNS can enhance task performance through activation of the central cholinergic system. These results highlight the importance of cholinergic modulation for the efficacy of VNS and may contribute to further refinement of VNS methodology for clinical conditions.

OBJECTIVES/UNASSIGNED:Acute post-thyroidectomy bilateral vocal cord paresis or paralysis (BVCP) is often managed with observation, botulinum toxin injection or tracheostomy. However, only a few cases discuss obstructive sleep apnea (OSA) in the context of BVCP with limited exploration of home sleep test (HST) and continuous positive airway pressure (CPAP) as post-operative assessment and management tools. This study suggests CPAP as a less invasive approach while awaiting vocal cord recovery. METHODS/UNASSIGNED:A retrospective chart review was conducted on 2 female patients who presented with dyspnea and sleep-disordered breathing (SDB) symptoms post-thyroidectomy. Both patients underwent laryngoscopy and HSTs, followed by CPAP prescription. RESULTS/UNASSIGNED:), aged 66 and 77 respectively, presented with post-surgery dyspnea and SDB symptoms. Laryngoscopy revealed left vocal cord paresis and right vocal cord paralysis in both cases. Although tracheostomy could provide definitive treatment, both cases were deferred for non-invasive options, which led to HST, confirming moderate OSA (PAT-derived apnea-hypopnea index (pAHI): 18/hour and 27.1/hour) leading to CPAP recommendation. In Case 2, 5 weeks of CPAP use resulted in dramatic improvements in her sleep quality, with continued benefits at 3-month follow-up. CONCLUSION/UNASSIGNED:These cases underscore the value of considering sleep studies and CPAP as adjunctive tools in acute post-thyroidectomy BVCP management while awaiting vocal motion recovery. This report also further supports that BVCP sufficiently narrows the glottic airway, predisposing patients to OSA.

OBJECTIVES/OBJECTIVE:Vocal fold scar remains a therapeutic challenge. Vocal fold fibroblasts (VFFs) secrete extracellular matrix (ECM), and transforming growth factor-beta 1 (TGF-β1)-mediated fibroblast to myofibroblast differentiation is central to the development of fibrosis. The transient receptor potential (TRP) channel superfamily is a group of nonselective cation channels, and activation of TRP ankyrin 1 (TRPA1) channel has been shown to have antifibrotic effects through TGF-β1/Smad signaling in various organs. This study aimed to elucidate expression of TRPA1 and the impact of TRPA1 activation on TGF-β1/Smad signaling in VFFs. METHODS: M) for 4 or 24 h. Trpa1, Smad3, Smad7, Col1a1, Acta2, and Has1 mRNA expression were quantified via qPCR. RESULTS:TRPA1 was expressed in cultured VFFs and the lamina propria. TGF-β1 administration significantly increased Trpa1 compared to control. AITC alone did not alter Smad3, Smad7, Acta2, or ECM related genes. However, the combination of AITC and TGF-β1 significantly increased Smad3 and decreased Smad7 and Acta2 compared to TGF-β1 alone; A-967079 significantly reduced this response. CONCLUSIONS:VFFs expressed TRPA1, and the activation of TRPA1 regulated TGF-β1/Smad signaling in VFFs. These findings provide preliminary insights into potential anti-fibrotic mechanisms of TRPA1 activation through TGF-β1/Smad signaling in VFFs. LEVEL OF EVIDENCE/METHODS:NA Laryngoscope, 2024.

BACKGROUND:Preoperative review of computed tomography (CT) imaging assists with endoscopic sinus surgery (ESS) planning, where trainees may benefit from a systematic approach. We have previously developed an optimized preoperative checklist for sinus CT imaging using an iterative modified Delphi method. OBJECTIVE:In this study, we assess the utility of an optimized preoperative checklist for residents performing ESS. METHODS:Resident sinus CT scan education consisted of a preintervention questionnaire, an 18-min video outlining the optimized preoperative checklist, and a delayed postintervention questionnaire; these were distributed via Qualtrics to otolaryngology residents across 5 training programs in the NY metro area. The preintervention questionnaire contained 25 survey questions and a 225-point quiz on sinus CT anatomy; the delayed postintervention questionnaire contained the same 25 survey questions and a second, distinct 225-point quiz. RESULTS: < .001). Resident habitual utilization of a systematic preoperative CT imaging checklist increased significantly from 21.6% to 72.9% as a result of the curriculum intervention. CONCLUSION/CONCLUSIONS:We find that an educational program centered on an iteratively optimized preoperative checklist for ESS improves the ability of trainees to identify critical sinus CT structures. Further integration of checklists and educational curricula may enhance rhinology education efforts and improve surgical anatomy competency.