Faculty Bibliography

Rat ultrasonic vocalizations (USVs) have traditionally been used in psychosocial and psychobiological studies to understand emotion, social behavior, cognition, and associative learning. However, recent studies have expanded the goal of USVs to include the study of the laryngeal system and the effects of disease processes on vocal sensorimotor control. Without the foundational understanding of the goals of this area of laryngological research, fundamental differences in study objectives between psychobehavioral and laryngological studies can easily be missed, leading to misconceptions and misinterpretations of the role USVs play in laryngology-focused studies. Standardization of terminology and methods are also needed to improve communication, enhance study replicability, and prevent ambiguity that can lead to misinterpretations of study objectives and findings in this line of research. The primary objective is to describe the role of USVs in studies of laryngeal anatomy and physiology, with a focus on their connections to the neuromuscular and neurological aspects of the laryngeal system, particularly in relation to vocal sensorimotor control and voice disorders. It is intended for novice investigators interested in laryngology-specific USV research. Researchers experienced in USV studies within the context of the larynx and vocal sensorimotor control first outline the development and refinement of various USV elicitation methods. They provide insights into how these approaches have been tested across different studies and laboratories. Finally, they advocate for standardizing terminology and methodologies to enhance study replicability, reduce ambiguity, and foster collaboration across research groups.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:This study investigated the effects of the "crack-sob" onset-a distinctive vocal technique combining a sob gesture with an intentional pitch break-on vocal fold function during high-intensity singing. We hypothesized that this onset would either decrease glottal adduction and increase vocal fold vibration stability or alternatively, show no measurable effects while still providing perceived benefits to singers. STUDY DESIGN/METHODS:Prospective observational cohort study. METHODS:Twenty professional musical theatre singers (10 male, 10 female) performed high-intensity sustained notes with and without the crack-sob onset using both a control phrase and self-selected repertoire. Electroglottography measured contact quotient (CQ) and its relative standard deviation (relSDCQ). Acoustic analysis quantified smoothed cepstral peak prominence (CPPS), harmonics-to-noise ratio (HNR), and vocal intensity (dB SPL). Linear mixed effects modeling was used to analyze the effects of the crack-sob maneuver, with sex and vocal phrase as covariates. RESULTS:The crack-sob onset showed no significant effects on any measured parameters. CQ remained consistent at 66% regardless of onset type. No significant changes were observed in CPPS, dB SPL, relSDCQ, or HNR when using the crack-sob onset, with all effect sizes below 0.1. Significant differences were found between control and self-selected phrases, with the control phrase showing higher CPPS (+2.6 dB), intensity (+2.7 dB SPL), and HNR (+4.3). CONCLUSIONS:The crack-sob onset does not significantly alter objective measures of vocal fold adduction or vibratory stability during sustained high-intensity phonation in trained singers. The technique's reported benefits may be primarily perceptual rather than physiological, suggesting its value as a pedagogical tool for managing singer effort without compromising vocal function.

Embryonic development in many species, including case reports in humans, can be temporarily halted before implantation during a process called diapause. Facultative diapause occurs under conditions of maternal metabolic stress such as nursing. While molecular mechanisms of diapause have been studied, a natural inducing factor has yet to be identified. Here, we show that oxytocin induces embryonic diapause in mice. We show that gestational delays were triggered during nursing or optogenetic stimulation of oxytocin neurons simulating nursing patterns. Mouse blastocysts express oxytocin receptors, and oxytocin induced delayed implantation-like dispersion in cultured embryos. Last, oxytocin receptor-knockout embryos transferred into wild-type surrogates had low survival rates during diapause. Our results indicate that oxytocin coordinates timing of embryonic development with uterine progression through pregnancy, providing an evolutionarily conserved mechanism for ensuring successful reproduction.

OBJECTIVES/OBJECTIVE:To assess a decade of experience of treating patients with high hearing risk cerebellopontine angle (CPA) epidermoid lesions and examine factors influencing postoperative outcomes, particularly hearing preservation. STUDY DESIGN/METHODS:Retrospective chart review. SETTING/METHODS:Single tertiary-referral center. PATIENTS/METHODS:Adults with CPA epidermoid lesions who presented with hearing loss or evidence of lesion involving vestibulocochlear nerve. INTERVENTIONS/METHODS:The studied intervention was microsurgical resection. MAIN OUTCOME MEASURES/METHODS:Main outcome measures included extent of resection, hearing preservation rate for patients with postoperative audiograms, and disease progression. RESULTS:Twenty-three adults with an average tumor volume of 15.63 ± 16.2 cm3 were included. Five lesions (22%) involved the full internal auditory canal (IAC), 11 (48%) had partial involvement, and 5 (22%) were IAC sparing. Most patients with IAC involvement (88%) had circumferential invasion of the canal. Patients underwent either a retrosigmoid (18, 79%) or combined retrolabyrinthine transpetrosal approach (5, 22%), and gross total resection was achieved in most cases (13, 57%). Of 12 patients with postoperative audiograms, 10 (83%) had preoperative hearing preserved. There was no statistically significant change in hearing scores with treatment based on preoperative extent of IAC involvement. Ten patients (43%) had residual lesions postoperatively, and 6 exhibited progression. One patient ultimately required reoperation 6 years after initial surgery. CONCLUSIONS:Preoperative hearing was preserved in the majority of the patients who underwent resection of CPA epidermoids via a retrosigmoid or transpetrosal approach. CPA epidermoids often invaded the IAC; however, degree of invasion was not associated with hearing outcomes.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Hydrocephalus after Gamma Knife® stereotactic radiosurgery (SRS) for vestibular schwannomas is a rare but manageable occurrence. Most series report post-SRS communicating hydrocephalus in about 1% of patients, thought to be related to a release of proteinaceous substances into the cerebrospinal fluid. While larger tumor size and older patient age have been associated with post-SRS hydrocephalus, the influence of baseline ventricular anatomy on hydrocephalus risk remains poorly defined. METHODS:A single-institution retrospective cohort study examining patients who developed symptomatic communicating hydrocephalus after undergoing Gamma Knife® SRS for unilateral vestibular schwannomas from 2011 to 2021 was performed. Patients with prior hydrocephalus and cerebrospinal fluid diversion or prior surgical resection were excluded. Baseline tumor volume, third ventricle width, and Evans Index (EI)-maximum width of the frontal horns of the lateral ventricles/maximum internal diameter of the skull-were measured on axial postcontrast T1-weighted magnetic resonance imaging. RESULTS:A total of 378 patients met the inclusion criteria; 14 patients (3.7%) developed symptomatic communicating hydrocephalus and 10 patients (2.6%) underwent shunt placement and 4 patients (1.1%) were observed with milder symptoms. The median age of patients who developed hydrocephalus was 69 years (IQR, 67-72) and for patients younger than age 65 years, the risk was 1%. For tumor volumes <1 cm3, the risk of requiring shunting was 1.2%. The odds of developing symptomatic hydrocephalus were 5.0 and 7.7 times higher in association with a baseline EI > 0.28 (P = .024) and tumor volume >3 cm3 (P = .007), respectively, in multivariate analysis. Fourth ventricle distortion on pre-SRS imaging was significantly associated with hydrocephalus incidence (P < .001). CONCLUSION/CONCLUSIONS:Patients with vestibular schwannoma with higher baseline EI, larger tumor volumes, and fourth ventricle deformation are at increased odds of developing post-SRS hydrocephalus. These patients should be counseled regarding risk of hydrocephalus and carefully monitored after SRS.

OBJECTIVE:To compare salivary flow rates between females and males, before and after radiation therapy (RT) for head and neck cancer (HNC). METHODS:Prospective observational multicenter cohort study (OraRad). Stimulated whole salivary flow was measured before RT and at 6 and 18 months after RT. RESULTS:Mean (95% confidence interval) salivary flow in g/min before RT was 0.81 (0.71, 0.90) in females (n = 107) and 1.20 (1.15, 1.25) in males (n = 391) (p < 0.001); at 6 months was 0.34 (0.24, 0.44) in females and 0.50 (0.44, 0.55) in males (p = 0.01); at 18 months was 0.49 (0.38, 0.59) in females and 0.70 (0.64, 0.75) in males (p < 0.001). Median nadir salivary flow after RT was 0.22 in females and 0.35 in males (p < 0.001). A lower nadir salivary flow in females, but not males, was associated with an increased risk for tooth failure (p = 0.02). CONCLUSIONS:Females with HNC have lower stimulated whole salivary flow than males, before and after RT. Low salivary flow after RT may be a risk factor for tooth failure among females. The lower pre-RT salivary flow rates in females, combined with prior literature in other populations, indicates that, in general, females have lower stimulated salivary flow than males.

Aggression is an evolutionarily conserved behaviour that controls social hierarchies and protects valuable resources. In mice, aggressive behaviour can be broken down into an appetitive phase, which involves approach and investigation, and a consummatory phase, which involves biting, kicking and wrestling¹. Here, by performing an unsupervised weighted correlation network analysis on whole-brain FOS expression in mice, we identify a cluster of brain regions, including hypothalamic and amygdalar subregions and olfactory cortical regions, that are highly co-activated in male but not in female aggressors. The posterolateral cortical amygdala (COApl)-an extended olfactory structure-was found to be a hub region, on the basis of the number and strength of correlations with other regions in the cluster. Our data also show that oestrogen receptor 1 (Esr1)-expressing cells in the COApl (COApl^Esr1) exhibit increased activity during attack behaviour and during bouts of investigation that precede an attack, in male mice only. Chemogenetic or optogenetic inhibition of COApl^Esr1 cells in male aggressors reduces aggression and increases pro-social investigation without affecting social reward and reinforcement behaviour. We further show that COApl^Esr1 projections to the ventromedial hypothalamus and central amygdala are necessary for these behaviours. Collectively, these data suggest that, in aggressive males, COApl^Esr1 cells respond specifically to social stimuli, thereby enhancing their salience and promoting attack behaviour.

PURPOSE/OBJECTIVE:To investigate how adults with unilateral vestibular hypofunction and healthy controls incorporate visual and auditory cues for postural control in an abstract visual environment. METHODS:] components in low [0, 0.25 Hz], mid [0.25, 0.5 Hz] and high [0.5, 1 Hz] frequencies in the anterior-posterior direction. We used linear mixed-effects models to compares healthy controls (n = 41, mean age 52 years, range 22-78) to participants with unilateral peripheral vestibular hypofunction (n = 28, 61.5, 27-82), adjusting for age. RESULTS:Variance and low PSD: we observed a significant vestibular by visual load interaction in the presence of sounds, such that the vestibular group had significantly higher sway than controls only on dynamic visuals in the presence of sounds. Mid PSD: the vestibular group had significantly higher sway than controls regardless of condition. High PSD: the vestibular group had significantly higher sway than controls, except for the presence of sounds on static visuals. CONCLUSIONS:Patients with vestibular hypofunction used sounds to reduce sway in a static abstract environment and were somewhat destabilized by it in a dynamic environment. This suggests that sounds, when played from headphones, may function as an auditory anchor under certain level of challenge and specific tasks regardless of whether it's stationary or moving. Our results support that increased sway in middle frequencies reflects vestibular dysfunction.

PURPOSE/OBJECTIVE:Mental health disorders, substance abuse, and tobacco use are prevalent in the US population. However, the association between these conditions and head and neck cancer (HNC) stage is poorly understood. This research aims to uncover the relationship between pre-existing mental health disorders, substance abuse, and tobacco use and HNC stage at diagnosis in patients receiving care in an integrated, public safety-net healthcare system. METHODS:This study was a secondary data analysis of linked hospital tumor registries and electronic health record (EHR) data. The study's primary independent variables were the comorbidities of mental health disorders, substance abuse, and tobacco use. The dependent variable was HNC stage at diagnosis, operationalized as early stage (i.e., stages I, II, and III) and advanced stage (stage IV, IVA, IVB, or IVC). The analysis included multivariable logistic regression adjusted for covariates of demographic variables, tumor anato RESULTS: The study population consisted of 357 patients with median age of 59 years, and was primarily male (77%), diverse (Black or African American 41%; Hispanic 22%), and from neighborhoods with low income (median average annual household income $39,785). Patients with a history of mental health disorders with or without tobacco use had significantly lower odds of advanced stage HNC at diagnosis (adjusted OR = 0.35, 95% Confidence Interval [CI]: 0.17-0.72.) while patients with a history of substance abuse with or without tobacco use had significantly higher odds of advanced stage HNC at diagnosis (adjusted OR 1.41, 95% CI: 1.01-1.98) than patients with no history of mental health disorders, substance abuse, or tobacco use. CONCLUSIONS:The relationship between HNC stage at diagnosis and the comorbidities of mental health disorders, substance abuse, or tobacco differs depending on the type and co-occurrence of these comorbidities. These findings demonstrate the need for innovative care delivery models and education initiatives tailored to meet the needs of patients with mental health disorders, substance abuse, and tobacco use that facilitate early detection of HNC.

The pancreas tumor microbiota may influence tumor microenvironment and influence survival in early-stage pancreatic ductal adenocarcinoma (PDAC); however, current studies are limited and small. We investigated the relationship of tumor microbiota to survival in 201 surgically resected patients with localized PDAC (Stages I-II), from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) cohorts. We characterized the tumor microbiome using RNA-sequencing data. We examined the association of the tumor microbiome with overall survival (OS), via meta-analysis with the Cox PH model. A microbial risk score (MRS) was calculated from the OS-associated microbiota. We further explored whether the OS-associated microbiota is related to host tumor immune infiltration. PDAC tumor microbiome α- and β-diversities were not associated with OS; however, 11 bacterial species, including species of Gammaproteobacteria, confirmed by extensive resampling, were significantly associated with OS (all Q < 0.05). The MRS summarizing these bacteria was related to a threefold change in OS (hazard ratio = 2.96 per standard deviation change in the MRS, 95% confidence interval = 2.26-3.86). This result was consistent across the two cohorts and in stratified analyses by adjuvant therapy (chemotherapy/radiation). Identified microbiota and the MRS also exhibited association with memory B cells and naïve CD4⁺ T cells, which may be related to the immune landscape through BCR and TCR signaling pathways. Our study shows that a unique tumor microbiome structure, potentially affecting the tumor immune microenvironment, is associated with poorer survival in resected early-stage PDAC. These findings suggest that microbial mechanisms may be involved in PDAC survival, potentially informing PDAC prognosis and guiding personalized treatment strategies.IMPORTANCEMuch of the available data on the PDAC tumor microbiome and survival are derived from relatively small and heterogeneous studies, including those involving patients with advanced stages of pancreatic cancer. There is a critical knowledge gap in terms of the tumor microbiome and survival in early-stage patients treated by surgical resection; we expect that advancements in survival may initially be best achieved in these patients who are treated with curative intent.