Risk factors and outcomes in patients with cochlear nerve deficiency.

INTRODUCTION: Cochlear nerve deficiency (CND) is a cause of sensorineural hearing loss made by radiologic criteria. There is sparse literature involving audiological outcomes and cochlear implantation (CI) success in patients with CND. METHODS: A retrospective chart review of all patients with sensorineural hearing loss at a tertiary children's hospital from 2000 to 2020 was conducted. Patients with CND on radiographic imaging were included and categorized as hypoplastic, aplastic, or indeterminate. RESULTS: In this study, 53 patients were identified with CND, totaling 70 ears. Of the 53 patients, 30 (56.6 %) were male, 8 (16.0 %) had a family history of childhood hearing loss, 6 (11.3 %) were born preterm, and 11 (23.4 %) required neonatal intensive care admission. The median maternal age was 29 years old [IQR: 27, 35], and 8 (15 %) patients were born to mothers with diabetes. Of the 70 ears, 49 (70 %) utilized conventional hearing aids, 12 (17.1 %) utilized a bone-anchored hearing aid, and 10 (14.3 %) underwent CI. Of the 10 ears implanted, 4 (40 %) ears had nerves classified as hypoplastic, 3 (30 %) as aplastic, and 3 (30 %) as indeterminate. Improvement in pure tone averages compared to preoperative testing was demonstrated in 8 (80 %), and 6 (60 %) displayed improved speech awareness thresholds. CONCLUSION: This study demonstrates that there may be an association between CND and maternal diabetes and NICU admission. There are variable results with hearing amplification options in patients with CND, and further research is needed to better describe the role of CI, bone-anchored hearing aids and conventional hearing aids in patients with CND.

Global conservation prioritization for the Orchidaceae.

Quantitative assessments of endemism, evolutionary distinctiveness and extinction threat underpin global conservation prioritization for well-studied taxa, such as birds, mammals, and amphibians. However, such information is unavailable for most of the world's taxa. This is the case for the Orchidaceae, a hyperdiverse and cosmopolitan family with incomplete phylogenetic and threat information. To define conservation priorities, we present a framework based on phylogenetic and taxonomic measures of distinctiveness and rarity based on the number of regions and the area of occupancy. For 25,434 orchid species with distribution data (89.3% of the Orchidaceae), we identify the Neotropics as hotspots for richness, New Guinea as a hotspot for evolutionary distinctiveness, and several islands that contain many rare and distinct species. Orchids have a similar proportion of monotypic genera as other Angiosperms, however, more taxonomically distinct orchid species are found in a single region. We identify 278 species in need of immediate conservation actions and find that more than 70% of these do not currently have an IUCN conservation assessment and are not protected in ex-situ collections at Botanical Gardens. Our study highlights locations and orchid species in urgent need of conservation and demonstrates a framework that can be applied to other data-deficient taxa.

Not All Mice Are Created Equal: Interval Timing Accuracy and Scalar Timing in 129, Swiss-Webster, and C57Bl/6 Mice.

Many species, including humans, show both accurate timing-appropriate time estimation in the seconds to minutes range-and scalar timing-time estimation error varies linearly with estimated duration. Behavioral paradigms aimed at investigating interval timing are expected to evaluate these dissociable characteristics of timing. However, when evaluating interval timing in models of neuropsychiatric disease, researchers are confronted with a lack of adequate studies about the parent (background) strains, since accuracy and scalar timing have only been demonstrated for the C57Bl/6 strain of mice (Buhusi et al., 2009). We used a peak-interval procedure with three intervals-a protocol in which other species, including humans, demonstrate accurate, scalar timing-to evaluate timing accuracy and scalar timing in three strains of mice frequently used in genetic and behavioral studies: 129, Swiss-Webster, and C57Bl/6. C57Bl/6 mice showed accurate, scalar timing, while 129 and Swiss-Webster mice showed departures from accuracy and/or scalar timing. Results suggest that the genetic background / strain of the mouse is a critical variable for studies investigating interval timing in genetically-engineered mice. Our study validates the PI procedure with multiple intervals as a proper technique, and the C57Bl/6 strain as the most suitable genetic background to date for behavioral investigations of interval timing in genetically engineered mice modeling human disorders. In contrast, studies using mice in 129, Swiss-Webster, or mixed-background strains should be interpreted with caution, and thorough investigations of accuracy and scalar timing should be conducted before a less studied strain of mouse is considered for use in timing studies.

Extinct in the wild: The precarious state of Earth's most threatened group of species.

Extinct in the Wild (EW) species are placed at the highest risk of extinction under the International Union for Conservation of Nature Red List, but the extent and variation in this risk have never been evaluated. Harnessing global databases of ex situ animal and plant holdings, we report on the perilous state of EW species. Most EW animal species-already compromised by their small number of founders-are maintained at population sizes far below the thresholds necessary to ensure demographic security. Most EW plant species depend on live propagation by a small number of botanic gardens, with a minority secured at seed bank institutions. Both extinctions and recoveries are possible fates for EW species. We urgently call for international effort to enable the latter.

Taxonomic similarity does not predict necessary sample size for ex situ conservation: a comparison among five genera.

Effectively conserving biodiversity with limited resources requires scientifically informed and efficient strategies. Guidance is particularly needed on how many living plants are necessary to conserve a threshold level of genetic diversity in ex situ collections. We investigated this question for 11 taxa across five genera. In this first study analysing and optimizing ex situ genetic diversity across multiple genera, we found that the percentage of extant genetic diversity currently conserved varies among taxa from 40% to 95%. Most taxa are well below genetic conservation targets. Resampling datasets showed that ideal collection sizes vary widely even within a genus: one taxon typically required at least 50% more individuals than another (though Quercus was an exception). Still, across taxa, the minimum collection size to achieve genetic conservation goals is within one order of magnitude. Current collections are also suboptimal: they could remain the same size yet capture twice the genetic diversity with an improved sampling design. We term this deficiency the 'genetic conservation gap'. Lastly, we show that minimum collection sizes are influenced by collection priorities regarding the genetic diversity target. In summary, current collections are insufficient (not reaching targets) and suboptimal (not efficiently designed), and we show how improvements can be made.

Applying the zoo model to conservation of threatened exceptional plant species.

Maintaining a living plant collection is the most common method of ex situ conservation for plant species that cannot be seed banked (i.e., exceptional species). Viability of living collections, and their value for future conservation efforts, can be limited without coordinated efforts to track and manage individuals across institutions. Using a pedigree-focused approach, the zoological community has established an inter-institutional infrastructure to support long-term viability of captive animal populations. We assessed the ability of this coordinated metacollection infrastructure to support the conservation of 4 plant species curated in living collections at multiple botanic gardens around the world. Limitations in current practices include the inability to compile, share, and analyze plant collections data at the individual level, as well as difficulty in tracking original provenance of ex situ material. The coordinated metacollection framework used by zoos can be adopted by the botanical community to improve conservation outcomes by minimizing the loss of genetic diversity in collections. We suggest actions to improve ex situ conservation of exceptional plant species, including developing a central database to aggregate data and track unique individuals of priority threatened species among institutions and adapting a pedigree-based population management tool that incorporates life-history aspects unique to plants. If approached collaboratively across regional, national, and global scales, these actions could transform ex situ conservation of threatened plant species.

Aplicación del Modelo Zoológico a la Conservación de Especies Excepcionales de Plantas Amenazadas Resumen El mantenimiento de una colección de plantas vivas es el método más común para de conservación ex situ para especies de plantas que no pueden almacenarse en bancos de semillas (i. e., especies excepcionales). La viabilidad de las colecciones vivientes, junto con el valor que representan para los futuros esfuerzo de conservación, puede estar limitada si no existen esfuerzos coordinados para rastrear y manejar a los individuos entre las instituciones. Mediante una estrategia enfocada en el linaje, la comunidad de zoológicos ha establecido una infraestructura interinstitucional que respalda la viabilidad a largo plazo de las poblaciones de animales en cautiverio. Evaluamos la habilidad de esta infraestructura coordinada de metacolecciones para apoyar en la conservación de cuatro especies de plantas curadas en colecciones vivientes en varios jardines botánicos de todo el mundo. Las limitaciones de las prácticas contemporáneas incluyen la incapacidad de recopilar, compartir y analizar los datos de las colecciones de plantas a nivel individual, así como la dificultad de rastrear la procedencia original del material ex situ. El marco de trabajo de metacolecciones coordinadas que utilizan los zoológicos puede ser adoptado por la comunidad botánica para mejorar los resultados de conservación al minimizar la pérdida de la diversidad genética que ocurre en las colecciones. Sugerimos acciones que aumenten la conservación ex situ de las especies excepcionales de plantas. Estas acciones incluyen el desarrollo de una base de datos central para acumular datos y rastrear entre las instituciones a los individuos únicos de las especies amenazadas prioritarias y la adaptación de una herramienta de manejo poblacional basada en el linaje que incorpore los aspectos únicos de la historia de vida de las plantas. Si estas acciones se plantean colaborativamente a escala regional, nacional y global, podrían transformar la conservación ex situ de las especies amenazadas de plantas.

Delayed Identification of Infants Who Are Deaf or Hard of Hearing - Minnesota, 2012-2016.

Few studies have examined factors associated with the timing of identification of hearing loss within a cohort of infants identified as deaf or hard of hearing (DHH) and what factors are associated with delayed identification. Minnesota Early Hearing Detection and Intervention (EHDI) personnel studied deidentified data from 729 infants with confirmed congenital hearing loss (i.e., hearing loss identification after not passing newborn hearing screening) born in Minnesota during 2012-2016. Differences in likelihood of delayed identification of congenital hearing loss (defined as not passing newborn hearing screening and age >3 months at the time of identification as DHH) based on multiple variables were analyzed. Overall, 222 (30.4%) infants identified as DHH had delayed identification. Multivariate regression showed that infants identified as DHH were significantly more likely to have delayed identification if they had 1) low birthweight, 2) public insurance, 3) a residence outside the metropolitan area, 4) a mother with a lower level of education, 5) a mother aged <25 years, or 6) a mother who was Hmong. Despite achievements of EHDI programs, disparities exist in timely identification of hearing loss. Using this information to develop public health initiatives that target certain populations could improve timely identification, reduce the risk for language delay, and enhance outcomes in children who are DHH.

Clinical outcomes with unfractionated heparin monitored by anti-factor Xa vs. activated partial Thromboplastin time.

Anti-factor Xa (anti-Xa) monitoring of unfractionated heparin (UFH) is associated with less time to achieve therapeutic anticoagulation compared to the activated partial thromboplastin time (aPTT). However, it is unknown whether clinical outcomes differ between these methods of monitoring. The aim of this research was to compare the rate of venous thrombosis and bleeding events in patients that received UFH monitored by anti-Xa compared to the aPTT. A retrospective review of electronic health records identified adult patients that received UFH given intravenously (IV) for ≥2 days, with either anti-Xa or aPTT monitoring at an academic tertiary care hospital. This was a pre/post study design conducted between January 1 to December 30, 2014 (aPTT), and January 1 to December 30, 2016 (anti-Xa). All UFH adjustments were based on institutional nomograms. The primary outcome was venous thrombosis and the secondary outcome was bleeding, both of which occurred between UFH administration and discharge from the index hospitalization. A total of 2500 patients were in the anti-Xa group and 2847 patients aPTT group. Venous thrombosis occurred in 10.2% vs 10.8% of patients in the anti-Xa and aPTT groups, respectively (P = .49). Bleeding occurred in 33.7% vs 33.6% of patients in the anti-Xa and aPTT groups, respectively (P = .94). Anti-Xa monitoring was not an independent predictor of either outcome in multivariate logistic regression analyses. Our study found no difference in clinical outcomes between anti-Xa and aPTT-based monitoring of UFH IV.

Analysis of archived newborn dried blood spots (DBS) identifies congenital cytomegalovirus as a major cause of unexplained pediatric sensorineural hearing loss.

PURPOSE: Congenital cytomegalovirus (cCMV) infection is the most common non-genetic cause of sensorineural hearing loss (SNHL). However, accurate diagnosis of cCMV as the etiology of SNHL is problematic beyond the neonatal period. This study therefore examined whether cCMV infection could be identified retrospectively in children presenting with unexplained SNHL to a multidisciplinary diagnostic outpatient otolaryngology clinic at an academic medical center in Minnesota. METHODS: Over a 4-year period, 57 patients with an age range of 3months to 10years with unexplained SNHL were recruited to participate in this study. Informed consent was obtained to test the archived dried blood spots (DBS) of these patients for cCMV infection by real-time PCR, targeting a highly conserved region of the CMV UL83 gene. Results were normalized to recovery of an NRAS gene control. Chart review was conducted to identify subjects who underwent genetic testing and/or neurodiagnostic imaging to investigate possible genetic, syndromic, or anatomical causes of SNHL. RESULTS: In total, 15 of the 57 children with unexplained SNHL tested positive for CMV DNA in their DBS (26%). A mean viral load of 8.3×104 (±4.1×104) [range, 1×103-6×105] copies/µg DNA was observed in subjects retrospectively diagnosed with cCMV. No statistically significant correlation was found between viral load and SNHL severity. CONCLUSIONS: A retrospective DBS analysis demonstrated that 26% of patients presenting with unexplained SNHL in childhood had cCMV. DBS testing is useful in the retrospective diagnosis of cCMV, and may provide definitive diagnostic information about the etiology of SNHL.

Tympanostomy Tube Placement in Children Using a Single-Pass Tool with Moderate Sedation.

Insertion of tympanostomy tubes is a common elective pediatric surgical procedure and is typically performed under general anesthesia. The potential to reduce general anesthetic requirements for young children has led to increased interest in alternatives for tympanostomy tube placement. A tympanostomy tube system, developed to enable tympanostomy tube placement in a single pass on conscious patients under moderate sedation, was evaluated. A prospective study on 128 children and 253 tympanostomy tube placements conducted at 4 centers in the United States demonstrated an 88.3% success rate in performing the procedure under moderate sedation with adverse events within normal rates reported in the literature. The feasibility of completing tympanostomy tube placement under moderate sedation enables avoidance of general anesthesia and provides additional choices to physicians and parents.

Cocaine sensitization in adult Long-Evans rats perinatally exposed to polychlorinated biphenyls.

Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxicants known to adversely affect the nervous system and more specifically the dopamine system. Developmental PCB exposure in rats has been shown to produce alterations in dopaminergic signaling that persist into adulthood. The reinforcing properties of psychostimulants are typically modulated via the dopaminergic system, so this project used a behavioral sensitization paradigm to evaluate whether perinatal PCB exposure altered sensitization to the psychostimulant cocaine. Long-Evans rats were perinatally exposed to 0, 3 or 6mg/kg/day of PCBs throughout gestation and lactation. One male and female pup from each litter was retained for behavioral testing. Both horizontal and vertical activity were used to measure cocaine sensitization following repeated injections of 10mg/kg cocaine (IP) on post-natal day (PND) 91-96 and again after a week in the home cage on PND 103. A final locomotor activity session following a challenge injection of 20mg/kg was given on PND 110 to further evaluate the availability of presynaptic dopamine stores. The PCB-exposed rats appeared to be pre-sensitized to cocaine as they exhibited a greater degree of cocaine-induced locomotor activation to the initial injections of cocaine and therefore demonstrated a more rapid onset of cocaine behavioral sensitization compared to non-exposed controls. These results add to the literature detailing how perinatal exposure to dopamine-disrupting contaminants can change the developing brain, thereby producing permanent changes in the neurobehavioral response to psychostimulants later in life.

Cocaine self-administration in male and female rats perinatally exposed to PCBs: Evaluating drug use in an animal model of environmental contaminant exposure.

Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxicants known to adversely impact human health. Ortho-substituted PCBs affect the nervous system, including the brain dopaminergic system. The reinforcing effects of psychostimulants are typically modulated via the dopaminergic system, so this study used a preclinical (i.e., rodent) model to evaluate whether developmental contaminant exposure altered intravenous self-administration (IV SA) for the psychostimulant cocaine. Long-Evans rats were perinatally exposed to 6 or 3 mg/kg/day of PCBs throughout gestation and lactation and compared with nonexposed controls. Rats were trained to lever press for a food reinforcer in an operant chamber under a fixed-ratio 5 (FR5) schedule and later underwent jugular catheterization. Food reinforcers were switched for infusions of 250 µg of cocaine, but the response requirement to earn the reinforcer remained. Active lever presses and infusions were higher in males during response acquisition and maintenance. The same sex effect was observed during later sessions which evaluated responding for cocaine doses ranging from 31.25-500 µg. PCB-exposed males (not females) exhibited an increase in cocaine infusions (with a similar trend in active lever presses) during acquisition, but no PCB-related differences were observed during maintenance, examination of the cocaine dose-response relationship, or progressive ratio (PR) sessions. Overall, these results indicated perinatal PCB exposure enhanced early cocaine drug-seeking in this preclinical model of developmental contaminant exposure (particularly the males), but no differences were seen during later cocaine SA sessions. As such, additional questions regarding substance abuse proclivity may be warranted in epidemiological studies evaluating environmental contaminant exposures. (PsycINFO Database Record

A comparison of presynaptic and postsynaptic dopaminergic agonists on inhibitory control performance in rats perinatally exposed to PCBs.

Polychlorinated Biphenyls (PCBs) are very stable environmental contaminants whose exposure induces a number of health and cognitive concerns. Currently, it is well known that PCB exposure leads to poor performance on inhibitory control tasks. It is also well known that dopamine (DA) depletion within medial prefrontal cortex (mPFC) leads to poor performance on inhibitory control tasks. However, what is not well established is whether or not the inhibitory control problems found following PCB exposure are mediated by DA depletion in mPFC. This study was an investigation into the link between perinatal exposure to PCBs, the effect of this exposure on DA neurotransmission in the mPFC, and inhibitory-control problems during adulthood using a rodent model. The current study served to determine if microinjections of different DA agonists (the presynaptic DA transporter inhibitor and vesicular monoamine transporter agonist bupropion, the postsynaptic DA receptor 2 (DAD2) agonist quinpirole, and the postsynaptic DA receptor 1 (DAD1) agonist SKF81297) directly into the mPFC would differentially improve performance on an inhibitory control task in rats perinatally exposed to an environmentally relevant PCB mixture. Findings suggest several significant sex-based differences on differential reinforcement of low rates (DRL) 15 performance as well as some evidence of differential effectiveness of the DA agonists based on PCB exposure group.

Stimulation-evoked dopamine release in the nucleus accumbens following cocaine administration in rats perinatally exposed to polychlorinated biphenyls.

Exposure to polychlorinated biphenyls (PCBs) alters brain dopamine (DA) concentrations and DA receptor/transporter function, suggesting the reinforcing properties of drugs of abuse acting on the DA system may be affected by PCB exposure. Female Long-Evans rats were orally exposed to 0, 3, or 6 mg/kg/day PCBs from 4 weeks prior to breeding until litters were weaned on postnatal day 21. In vivo fixed potential amperometry (FPA) was used in adult anesthetized offspring to determine whether perinatal PCB exposure altered (1) presynaptic DA autoreceptor (DAR) sensitivity, (2) electrically evoked nucleus accumbens (NAc) DA efflux following administration of cocaine, and (3) the rate of depletion of presynaptic DA stores. One adult male and female littermate were tested using FPA following a single injection of cocaine (20 mg/kg ip), whereas a second adult male and female littermate were tested following the last of seven daily cocaine injections of the same dose. The carbon fiber recording microelectrode was positioned in the NAc core, and DA oxidation currents (i.e., DA release) evoked by brief stimulation of the medial forebrain bundle (MFB) were quantified before and after administration of cocaine. PCB-exposed rats exhibited enhanced stimulation-evoked DA release (relative to baseline) following a single injection of cocaine. Although nonexposed controls exhibited typical DA sensitization following repeated cocaine administration, this effect was attenuated in PCB-exposed rats. In addition, DAR sensitivity was higher (males only), and the rate of depletion of presynaptic DA stores was greater in PCB-exposed animals relative to nonexposed controls. These results indicate that perinatal PCB exposure can modify DA synaptic transmission in the NAc in a manner previously shown to alter the reinforcing properties of cocaine.

Quality of life in youth with severe to profound sensorineural hearing loss.

IMPORTANCE: Adolescence is a life stage with rapid and major developmental changes, yet little is known about how these changes influence the quality of life of young people who are deaf or hard of hearing (DHH). OBJECTIVE: To determine differences in the 3 domains of a hearing-specific quality-of-life instrument between youth who had severe to profound sensorineural hearing loss based on whether they used no technology, hearing aids, or cochlear implants. DESIGN AND SETTING: A multi-institutional prospective cohort study. PARTICIPANTS: A convenience sample of 11- to 18-year-old youths with severe to profound sensorineural hearing loss recruited between January 1 and December 31, 2008. MAIN OUTCOME MEASURES: Youth Quality of Life-Research Instrument and Youth Quality of Life Instrument-Deaf and Hard of Hearing (YQoL-DHH) scores. The YQoL-DHH was composed of 3 domains: participation, self-acceptance/advocacy, and stigma-related quality of life. RESULTS: A total of 157 individuals participated. Overall mean (SD) age was 14.1 (2.3) years, and the female-male ratio was 82:75. Forty-nine individuals (31.2%) were not using any technology, 45 (28.7%) were using hearing aids, and 63 (40.1%) were using cochlear implants. Mean age of unilateral or first cochlear implant was 62.9 months. Thirty-eight individuals (24.2%) attended schools with DHH programs, 55 (35.0%) attended schools without DHH programs, and 58 (36.9%) attended schools for the deaf. Statistically significant differences were noted in YQoL-DHH participation and perceived stigma scores between the groups when stratified by technology used and school setting. CONCLUSIONS: These data suggest that the domains of quality of life as measured by our instrument differ significantly among youth based on technology used and school setting. Youth using no technology or cochlear implants tended to score higher than those using hearing aids in mainstream schools with or without DHH programs and in schools for the deaf. The YQoL-DHH instrument is able to detect differences in quality of life within a group of youth with severe to profound hearing loss.

Symptom duration and CT findings in pediatric deep neck infection.

OBJECTIVE: To investigate whether children with less than 48 hours of localized symptoms of deep neck infection are less likely to have an abscess on CT scan. STUDY DESIGN: Case series. SUBJECTS AND METHODS: The charts of children seen in a tertiary children's hospital for deep neck infections between 2000 and 2007 were reviewed. RESULTS: Of 179 children identified, 167 (93.3%) underwent a CT scan of the neck of which 102 (61.1%) were positive for abscess. There was no significant difference in the rate of abscess on CT between children with less than 48 hours of localizing symptoms and 48 or more hours of symptoms at 58.1 percent and 58.3 percent, respectively (P = 0.98). Furthermore, there was no significant difference in age, gender, C-reactive protein levels, disease location, or length of stay between children with and without abscess on CT. White blood cell counts were significantly higher in the abscess group (P = 0.01); however, the median white blood cell count in both groups was above normal. CONCLUSION: Because duration of symptoms does not predict finding of abscess on CT, it is appropriate to obtain a CT scan upon presentation in all children with symptoms concerning for neck abscess.

Airway interventions in children with Pierre Robin Sequence.

OBJECTIVE: To describe the interventions required for successful airway management in children with Pierre Robin Sequence (PRS). STUDY DESIGN: Case series. SUBJECTS AND METHODS: The records of both a cleft and craniofacial clinic and a pediatric otolaryngology clinic were searched, and all children with PRS were identified. Data concerning feeding interventions, airway interventions, and comorbid conditions were extracted. RESULTS: Seventy-four cases of PRS were identified. Thirty-eight of the 74 children required airway intervention other than prone positioning. Fourteen of these 38 were managed nonsurgically with nasopharyngeal airway and/or short-term endotracheal intubation, whereas the remaining 24 required surgical intervention. Eighteen of the 24 underwent distraction osteogenesis of the mandible, one underwent tracheostomy, and five underwent tracheostomy followed by eventual distraction. CONCLUSION: In our series, over 50 percent of children with PRS required an airway intervention. These were both nonsurgical and surgical. As otolaryngologists, we must be prepared for the challenges children with PRS may present and the interventions that may be necessary to successfully manage these difficult airways.

Tympanometry of a diverse group of preschool aged children.

OBJECTIVE: Ethnicity has been previously described as a risk factor for middle ear disease. Little data exist on the presence of middle ear disease based on tympanometry screening comparing Asian children and children of other races. METHODS: Two hundred and seventy children aged 3-5 were screened with tympanometry at six Head Start sites in St. Paul, Minnesota during the months of September and October of 2004. Gender, age, and race/ethnicity was recorded and entered into a database, along with values for canal volume, static admittance, peak pressure, and tympanometric width. RESULTS: Criteria for abnormal tympanometry were based on American Speech-Language Hearing Association (ASHA) recommendations for a failed tympanogram for 1-5 year olds (admittance <0.3 mmho or width >200 daPa). There were no statistically significant differences in failure rates between males and females. There were, however, more failures for Asian (predominantly Hmong) children compared to children of other races/ethnicities after adjusting for age and gender differences (OR=6.39, CI 3.65-11.2, p<0.001) and for children <4-years-old compared to children 4-5-years-old after adjusting for race and gender differences (OR=1.99, CI 1.03-3.84, p<0.05). CONCLUSIONS: Asian children were more than six times as likely to fail tympanometry as children of other races/ethnicities. The explanation for this difference is likely to be multifactorial, and further research is needed to characterize this difference.