Evaluating Fixed Single-Point Parameters When Applied to Vestibular Evoked Myogenic Potentials: The Effect of Single Point and Signal Window.

OBJECTIVES: Several studies have applied a common objective detection algorithm (fixed single point [ Fsp ]) for detection of the vestibular evoked myogenic potential (VEMP). However, fundamental parameters of Fsp , such as establishing the location and duration of a signal window, have not been examined. In addition, Fsp criterion values used for response detection have not been established for cervical VEMPs (cVEMPs) or ocular VEMPs (oVEMPs). The purpose of this article was to investigate the effect of various single points and signal windows on Fsp , as well as determining Fsp criteria to determine response presence for cVEMP and oVEMP in a group of young healthy participants. DESIGN: Twenty young healthy adults under the age of 30 and with no history of hearing or balance concerns were enrolled in the study protocol. Air-conducted cVEMPs and oVEMPs were evoked using 500 Hz tone bursts at 123 dB pSPL recorded at a fixed electromyography activation of 50 µV for cVEMPs and 35° gaze angle for oVEMPs. Responses were analyzed off-line using visual and objective detection. Fsp was applied to cVEMPs and oVEMPs using a range of single points and signal windows. RESULTS: Noise variance was lowest for cVEMPs at the latency of P1, and for oVEMPs noise variance was not significantly different across the single-point latencies. On average, extending the length of the signal window lowered the Fsp value in cVEMPs and oVEMPs. An Fsp value of 2.0 was chosen as the criterion cutoff associated with the 95th percentile during no-response conditions using group data for cVEMPs and oVEMPs, respectively. Fsp values for cVEMPs and oVEMPs were not significantly different from each other. DISCUSSION: This study established single-point latency and time-window parameters for VEMP-related applications of the Fsp detection algorithm. Fsp criteria values were established for cVEMP and oVEMP. Using these parameters, responses were detected in all participants.

Noncoding variants alter GATA2 expression in rhombomere 4 motor neurons and cause dominant hereditary congenital facial paresis.

Hereditary congenital facial paresis type 1 (HCFP1) is an autosomal dominant disorder of absent or limited facial movement that maps to chromosome 3q21-q22 and is hypothesized to result from facial branchial motor neuron (FBMN) maldevelopment. In the present study, we report that HCFP1 results from heterozygous duplications within a neuron-specific GATA2 regulatory region that includes two enhancers and one silencer, and from noncoding single-nucleotide variants (SNVs) within the silencer. Some SNVs impair binding of NR2F1 to the silencer in vitro and in vivo and attenuate in vivo enhancer reporter expression in FBMNs. Gata2 and its effector Gata3 are essential for inner-ear efferent neuron (IEE) but not FBMN development. A humanized HCFP1 mouse model extends Gata2 expression, favors the formation of IEEs over FBMNs and is rescued by conditional loss of Gata3. These findings highlight the importance of temporal gene regulation in development and of noncoding variation in rare mendelian disease.

Audiovestibular Findings in a Cohort of Patients with Chiari Malformation Type I and Dizziness.

Chiari Malformation Type I (CM1) is a neurological condition in which the cerebellar tonsils extend past the foramen magnum. While many studies have reported dizziness symptoms in patients with CM1, the prevalence of peripheral labyrinthine lesions is largely unknown. This study aimed to comprehensively describe the audiovestibular phenotype in a cohort of patients with CM1 expressly referred for dizziness. Twenty-four patients with CM1 and a complaint of dizziness/vertigo were evaluated. Hearing and auditory brainstem tract function were essentially normal. While vestibular abnormalities were most prevalent during rotational testing (33%), abnormal functional balance was the most common finding (40%). Patients with CM1 had a greater likelihood of exhibiting an abnormal sensory organization test (SOT) postural stability score for fixed platform conditions, and for the somatosensory analysis score. While no significant associations were identified between tonsillar ectopia extent and any vestibular/balance outcome measure, a significant negative association was identified between neck pain and the somatosensory sensory analysis score. Abnormal functional balance in the somatosensory domain was remarkable, with poorer scores associated with neck pain. An isolated peripheral vestibulopathy was present in only 8% of patients. Despite the low prevalence of vestibulopathy, vestibular/balance assessment is warranted to identify patients who may benefit from referral to specialized medical disciplines.

A new paradigm for assessing postural stability.

BACKGROUND: The sensory organization test (SOT) is an established and effective method for assessing postural stability and determining fall risk. SOT equilibrium scores are derived from the relationship between an individual's peak sway amplitude and a standard, theoretically-derived normal limits of stability (tLOS). Determining an individual's postural stability and fall risk based on this one-size-fits-all tLOS may overestimate functional equilibrium scores and underestimate fall risk when personal stability limits (pLOS) are reduced. RESEARCH QUESTION: The purpose of this study is to investigate whether LOS measured from a group of healthy adults is different from the tLOS, and whether SOT equilibrium scores are significantly different when calculated using pLOS versus the standard tLOS. METHODS: Sixty healthy volunteers were recruited into three age-groups: young (18-39), middle-aged (40-64), and elderly (65-80), with 10 males and 10 females in each age-group. Outcome measures included SOT and LOS. Additional measures o balance perception and functional mobility were obtained including the Activities Balance Confidence (ABC) scale and the timed-up-and-go test (TUG). The tLOS and pLOS were used to calculate standard (tSOT) and personalized (pSOT) equilibrium scores. RESULTS: The mean pLOS from the group of healthy adults was significantly lower than the tLOS. Consequently, the pSOT equilibrium scores were significantly lower than the standard SOT scores derived using the tLOS. SIGNIFICANCE: Individual measures of LOS are significantly lower than theoretical estimates of the LOS in healthy adults. This suggests that use of tLOS in the calculation of SOT equilibrium scores often overestimates postural stability and may have implications for the determination of fall risk.

Audiometric and Otologic Findings in Children and Young Adults with Neurofibromatosis Type 1 and Plexiform Neurofibromas.

OBJECTIVES: To characterize otologic and audiologic manifestations in our NF1 cohort and explore the relationship between otologic and audiologic findings in a subset of patients with ear-related plexiform neurofibromas (PNs). METHODS: Audiologic and otologic clinical evaluations were conducted on 102 patients with NF1 in a natural history study (5-45 years; M = 14.4 years; Mdn = 14). Testing included pure tone and speech audiometry, middle ear function, neurodiagnostic auditory brainstem response (ABR), auditory processing, and MRIs of the head and neck region. Patients referred to this study had an overall higher incidence and burden of PNs than the overall NF1 population. RESULTS: The majority of subjects in this cohort had normal hearing sensitivity (81%) and normal middle ear function (78%). Nineteen participants had hearing loss that ranged in degree from mild to profound, with the majority in the mild range. Hearing loss was twice as likely to be conductive than sensorineural. In patients with ear-related PNs (n = 12), hearing loss was predominantly conductive (60%). Seventy-five percent of ears with PNs had atypical tympanometric tracings that could not be characterized by the classic categories. In all 20 patients with a PN in the temporal bone, the ear canal was affected, and the PNs often extended to the surrounding soft tissue regions. CONCLUSIONS: People with NF1-related PNs in the temporal bone and adjacent skull base should have audiometric and otologic monitoring. Addressing hearing concerns should be part of routine clinical evaluations in patients with NF1. Magnetic resonance imaging (MRI) should be performed in patients with NF1 who have hearing loss. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:2770-2778, 2023.

Characterization of hearing-impairment in Generalized Arterial Calcification of Infancy (GACI).

BACKGROUND AND IMPORTANCE: Hearing loss (HL) has been sporadically described, but not well characterized, in Generalized Arterial Calcification of Infancy (GACI), a rare disease in which pathological calcification typically presents in infancy. OBJECTIVES: This study aims to describe the clinical audiologic and otologic features and potential etiology of hearing impairment in GACI and gain pathophysiological insight from a murine model of GACI. DESIGN: Cross-sectional cohort study of individuals with GACI. Murine ossicle micromorphology of the ENPP1asj/asj mutant compared to wild-type. SETTING: Clinical research hospital; basic science laboratory. PARTICIPANTS: Nineteen individuals with GACI who met clinical, biochemical, and genetic criteria for diagnosis. MAIN OUTCOMES AND MEASURES: Clinical, biochemical, and radiologic features associated with hearing status. RESULTS: Pure-tone thresholds could be established in 15 (n = 30 ears) of the 19 patients who underwent audiological assessments. The prevalence of HL was 50% (15/30) of ears, with conductive HL in 80% and sensorineural HL in 20%. In terms of patients with HL (n = 8), seven patients had bilateral HL and one patient had unilateral HL. Degree of HL was mild to moderate for 87% of the 15 ears with hearing loss. Of those patients with sufficient pure-tone and middle ear function data, 80% (8/10) had audiometric configurations suggestive of ossicular chain dysfunction (OCD). Recurrent episodes of otitis media (ROM) requiring pressure-equalizing tube placement were common. In patients who underwent cranial CT, 54.5% (6/11) had auricular calcification. Quantitative backscattered electron imaging (qBEI) of murine ossicles supports an OCD component of auditory dysfunction in GACI, suggesting loss of ossicular osteocytes without initiation of bone remodeling. CONCLUSIONS AND RELEVANCE: Hearing loss is common in GACI; it is most often conductive, and mild to moderate in severity. The etiology of HL is likely multifactorial, involving dysfunction of the ossicular chain and/or recurrent otitis media. Clinically, this study highlights the importance of early audiologic and otologic evaluation in persons with GACI. Novel findings of high rates of OCD and ROM may inform management, and in cases of unclear HL etiology, dedicated temporal bone imaging should be considered.

Audiologic and Otologic Clinical Manifestations of Loeys-Dietz Syndrome: A Heritable Connective Tissue Disorder.

OBJECTIVE: Loeys-Dietz syndrome (LDS) is a rare genetic connective tissue disorder resulting from TGF-ß signaling pathway defects and characterized by a wide spectrum of aortic aneurysm, arterial tortuosity, and various extravascular abnormalities. This study describes the audiologic, otologic, and craniofacial manifestations of LDS. STUDY DESIGN: Consecutive cross-sectional study. SETTING: Tertiary medical research institute. METHODS: Audiologic and clinical evaluations were conducted among 36 patients (mean ± SD age, 24 ± 17 years; 54% female) with genetically confirmed LDS. Cases were categorized into genetically based LDS types 1 to 4 (TGFBR1, TGFBR2, SMAD3, TGFB2, respectively). Audiometric characteristics included degree and type of hearing loss: subclinical, conductive, mixed, and sensorineural. RESULTS: LDS types 1 to 4 included 11, 13, 5, and 7 patients, respectively. In LDS-1, 27% had bilateral conductive hearing loss; 9%, unilateral mixed; and 36%, subclinical. In LDS-2, 38% had conductive hearing loss and 38% subclinical. In LDS-3 and LDS-4, 40% and 43% had bilateral sensorineural hearing loss, respectively. Degree of hearing loss ranged from mild to moderate. Bifid uvula was observed only in LDS-1 (55%) and LDS-2 (62%). Submucosal/hard cleft palates were primarily in LDS-1 and LDS-2. Posttympanostomy tympanic membrane perforations occurred in 45% (10/22 ears) of LDS-1 and LDS-2. There were 4 cases of cholesteatoma: 3 middle ear (LDS-1 and LDS-2) and 1 external ear canal (LDS-3). CONCLUSION: Conductive hearing loss, bifid uvula/cleft palate, and posttympanostomy tympanic membrane perforation are more common in LDS-1 and LDS-2 than LDS-3 and LDS-4, while sensorineural hearing loss was present only in LDS-3 and LDS-4. These LDS-associated key clinical presentations may facilitate an early diagnosis of LDS and thus prompt intervention to prevent related detrimental outcomes.

TUBB3 Arg262His causes a recognizable syndrome including CFEOM3, facial palsy, joint contractures, and early-onset peripheral neuropathy.

Microtubules are formed from heterodimers of alpha- and beta-tubulin, each of which has multiple isoforms encoded by separate genes. Pathogenic missense variants in multiple different tubulin isoforms cause brain malformations. Missense mutations in TUBB3, which encodes the neuron-specific beta-tubulin isotype, can cause congenital fibrosis of the extraocular muscles type 3 (CFEOM3) and/or malformations of cortical development, with distinct genotype-phenotype correlations. Here, we report fourteen individuals from thirteen unrelated families, each of whom harbors the identical NM_006086.4 (TUBB3):c.785G>A (p.Arg262His) variant resulting in a phenotype we refer to as the TUBB3 R262H syndrome. The affected individuals present at birth with ptosis, ophthalmoplegia, exotropia, facial weakness, facial dysmorphisms, and, in most cases, distal congenital joint contractures, and subsequently develop intellectual disabilities, gait disorders with proximal joint contractures, Kallmann syndrome (hypogonadotropic hypogonadism and anosmia), and a progressive peripheral neuropathy during the first decade of life. Subsets may also have vocal cord paralysis, auditory dysfunction, cyclic vomiting, and/or tachycardia at rest. All fourteen subjects share a recognizable set of brain malformations, including hypoplasia of the corpus callosum and anterior commissure, basal ganglia malformations, absent olfactory bulbs and sulci, and subtle cerebellar malformations. While similar, individuals with the TUBB3 R262H syndrome can be distinguished from individuals with the TUBB3 E410K syndrome by the presence of congenital and acquired joint contractures, an earlier onset peripheral neuropathy, impaired gait, and basal ganglia malformations.

Auditory phenotype of Smith-Lemli-Opitz syndrome.

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive multiple congenital malformation and intellectual disability syndrome resulting from variants in DHCR7. Auditory characteristics of persons with SLOS have been described in limited case reports but have not been systematically evaluated. The objective of this study is to describe the auditory phenotype in SLOS. Age- and ability-appropriate hearing evaluations were conducted on 32 patients with SLOS. A subset of 21 had auditory brainstem response testing, from which an auditory neural phenotype is described. Peripheral or retrocochlear auditory dysfunction was observed in at least one ear of 65.6% (21) of the patients in our SLOS cohort. The audiometric phenotype was heterogeneous and included conductive, mixed, and sensorineural hearing loss. The most common presentation was a slight to mild conductive hearing loss, although profound sensorineural hearing loss was also observed. Abnormal auditory brainstem responses indicative of retrocochlear dysfunction were identified in 21.9% of the patients. Many were difficult to test behaviorally and required objective assessment methods to estimate hearing sensitivity. Individuals with SLOS are likely to have hearing loss that may impact communication, including speech and language development. Routine audiologic surveillance should be conducted to ensure prompt management of hearing loss.

Vestibular phenotype-genotype correlation in a cohort of 90 patients with Usher syndrome.

Usher syndrome has been historically categorized into one of three classical types based on the patient phenotype. However, the vestibular phenotype does not infallibly predict which Usher genes are mutated. Conversely, the Usher syndrome genotype is not sufficient to reliably predict vestibular function. Here we present a characterization of the vestibular phenotype of 90 patients with clinical presentation of Usher syndrome (59 females), aged 10.9 to 75.5 years, with genetic variants in eight Usher syndromic genes and expand the description of atypical Usher syndrome. We identified unexpected horizontal semicircular canal reactivity in response to caloric and rotational stimuli in 12.5% (3 of 24) and 41.7% (10 of 24), respectively, of our USH1 cohort. These findings are not consistent with the classical phenotypic definition of vestibular areflexia in USH1. Similarly, 17% (6 of 35) of our cohort with USH2A mutations had saccular dysfunction as evidenced by absent cervical vestibular evoked myogenic potentials in contradiction to the classical assumption of normal vestibular function. The surprising lack of consistent genotypic to vestibular phenotypic findings as well as no clear vestibular phenotypic patterns among atypical USH cases, indicate that even rigorous vestibular phenotyping data will not reliably differentiate the three USH types.

The peroxisomal disorder spectrum and Heimler syndrome: Deep phenotyping and review of the literature.

The spectrum of peroxisomal disorders is wide and comprises individuals that die in the first year of life, as well as people with sensorineural hearing loss, retinal dystrophy and amelogenesis imperfecta. In this article, we describe three patients; two diagnosed with Heimler syndrome and a third one with a mild-intermediate phenotype. We arrived at these diagnoses by conducting complete ophthalmic (National Eye Institute), auditory (National Institute of Deafness and Other Communication Disorders), and dental (National Institute of Dental and Craniofacial Research) evaluations, as well as laboratory and genetic testing. Retinal degeneration with macular cystic changes, amelogenesis imperfecta, and sensorineural hearing loss were features shared by the three patients. Patients A and C had pathogenic variants in PEX1 and Patient B, in PEX6. Besides analyzing these cases, we review the literature regarding mild peroxisomal disorders, their pathophysiology, genetics, differential diagnosis, diagnostic methods, and management. We suggest that peroxisomal disorders are considered in every child with sensorineural hearing loss and retinal degeneration. These patients should have a dental evaluation to rule out amelogenesis imperfecta as well as audiologic examination and laboratory testing including peroxisomal biomarkers and genetic testing. Appropriate diagnosis can lead to better genetic counseling and management of the associated comorbidities.

Atypical and ultra-rare Usher syndrome: a review.

Usher syndrome has classically been described as a combination of hearing loss and rod-cone dystrophy; vestibular dysfunction is present in many patients. Three distinct clinical subtypes were documented in the late 1970s. Genotyping efforts have led to the identification of several genes associated with the disease. Recent literature has seen multiple publications referring to "atypical" Usher syndrome presentations. This manuscript reviews the molecular etiology of Usher syndrome, highlighting rare presentations and molecular causes. Reports of "atypical" disease are summarized noting the wide discrepancy in the spectrum of phenotypic deviations from the classical presentation. Guidelines for establishing a clear nomenclature system are suggested.

Hearing Loss and Irritability Reporting Without Vestibular Differences in Explosive Breaching Professionals.

Background: Blast exposure is a potential hazard in modern military operations and training, especially for some military occupations. Helmets, peripheral armor, hearing protection, and eye protection worn by military personnel provide some acute protection from blast effects but may not fully protect personnel against cumulative effects of repeated blast overpressure waves experienced over a career. The current study aimed to characterize the long-term outcomes of repeated exposure to primary blast overpressure in experienced career operators with an emphasis on the assessment of hearing and vestibular outcomes. Methods: Participants included experienced "breachers" (military and law enforcement explosives professionals who gain entry into structures through controlled detonation of charges) and similarly aged and experienced "non-breachers" (non-breaching military and law enforcement personnel). Responses to a clinical interview and performance on audiological and vestibular testing were compared. Results: Hearing loss, ringing in the ears, irritability, and sensitivity to light or noise were more common among breachers than non-breachers. Breachers reported more combat exposure than non-breachers, and subsequently, memory loss and difficulty concentrating were associated with both breaching and combat exposure. Vestibular and ocular motor outcomes were not different between breachers and non-breachers. Conclusion: Hearing-related, irritability, and sensitivity outcomes are associated with a career in breaching. Future studies examining long-term effects of blast exposure should take measures to control for combat exposure.

SLC26A4-linked CEVA haplotype correlates with phenotype in patients with enlargement of the vestibular aqueduct.

BACKGROUND: Recessive mutations of coding regions and splice sites of the SLC26A4 gene cause hearing loss with enlargement of the vestibular aqueduct (EVA). Some patients also have a thyroid iodination defect that can lead to multinodular goiter as part of Pendred syndrome. A haplotype of variants upstream of SLC26A4, called CEVA, acts as a pathogenic recessive allele in trans to mutations affecting the coding regions or splice sites of SLC26A4. Our first hypothesis is that CEVA, acting as a pathogenic recessive allele, is correlated with a less severe phenotype than mutations affecting the coding regions and splice sites of SLC26A4. Our second hypothesis is that CEVA acts as a modifier of the phenotype in patients with EVA caused by mutations affecting the coding regions or splice sites of both alleles of SLC26A4 or EVA caused by other factors. METHODS: This was a prospective cohort study of 114 individuals and 202 ears with EVA. To test our first hypothesis, we compared the thyroid and auditory phenotypes of subjects with mutations affecting coding regions of both alleles of SLC26A4 with those of subjects carrying CEVA in trans to mutations affecting the coding regions. To test our second hypothesis, we compared the phenotypes associated with the presence versus absence of CEVA among subjects with no coding region mutations, as well as among subjects with mutations affecting coding regions of both alleles. RESULTS: Subjects carrying CEVA in trans to a mutation of SLC26A4 have a normal thyroid phenotype and less severe hearing loss in comparison to individuals with mutations affecting coding regions of both alleles of SLC26A4. In subjects with no mutant alleles of SLC26A4, hearing loss was more severe in subjects who carry the CEVA haplotype in comparison to non-carriers. There was no correlation of CEVA with the phenotype of subjects with mutations affecting coding regions of both alleles. CONCLUSIONS: CEVA, acting as a likely pathogenic recessive allele, is associated with a less severe phenotype than alleles with a mutation affecting the coding regions or splice sites of SLC26A4. CEVA may act as a genetic modifier in patients with EVA caused by other factors.

All-night functional magnetic resonance imaging sleep studies.

BACKGROUND: Previous functional magnetic resonance imaging (fMRI) sleep studies have been hampered by the difficulty of obtaining extended amounts of sleep in the sleep-adverse environment of the scanner and often have resorted to manipulations such as sleep depriving subjects before scanning. These manipulations limit the generalizability of the results. NEW METHOD: The current study is a methodological validation of procedures aimed at obtaining all-night fMRI data in sleeping subjects with minimal exposure to experimentally induced sleep deprivation. Specifically, subjects slept in the scanner on two consecutive nights, allowing the first night to serve as an adaptation night. RESULTS/COMPARISON WITH EXISTING METHOD(S): Sleep scoring results from simultaneously acquired electroencephalography data on Night 2 indicate that subjects (n = 12) reached the full spectrum of sleep stages including slow-wave (M = 52.1 min, SD = 26.5 min) and rapid eye movement (REM, M = 45.2 min, SD = 27.9 min) sleep and exhibited a mean of 2.1 (SD = 1.1) nonREM-REM sleep cycles. CONCLUSIONS: It was found that by diligently applying fundamental principles and methodologies of sleep and neuroimaging science, performing all-night fMRI sleep studies is feasible. However, because the two nights of the study were performed consecutively, some sleep deprivation from Night 1 as a cause of the Night 2 results is likely, so consideration should be given to replicating the current study with a washout period. It is envisioned that other laboratories can adopt the core features of this protocol to obtain similar results.

Examination of Utricular Response Using oVEMP and Unilateral Centrifugation Rotation Testing.

OBJECTIVES: Significant advancements have been made toward the clinical assessment of utricular function through ocular vestibular-evoked myogenic potentials (oVEMP) and unilateral centrifugation (UCF) testing. To date, no study has examined intrasubject relationships between these measures. The study hypothesis was that intrasubject responses from oVEMP and UCF testing would be correlated inasmuch as both tests have been reported to assess utricular function. DESIGN: UCF rotations and oVEMP testing were performed on healthy volunteers, aged 18 to 62 years. A within-subject study design compared and correlated UCF outcome measures of ocular counterroll, subjective visual vertical, and ocular counterroll-gravitational inertial acceleration slope against peak to peak oVEMP N1-P1 amplitude. RESULTS: Correlational analyses failed to reveal any significant relationships between oVEMP amplitude and UCF responses suggesting that these tests may be inciting different response properties within the utricular system. CONCLUSIONS: Various anatomical and physiological differences within the utricle, in addition to the fundamental differences in stimulus properties between the oVEMP and UCF tests, could explain the lack of significant correlations between these measures and suggest that oVEMP and UCF testing may be complimentary in their evaluation of the utricular system. These data reinforce the complexities of the utricular system and provide further insight into the difficulties encountered in its clinical assessment.

Association of Hearing Loss and Otologic Outcomes With Fibrous Dysplasia.

Importance: Fibrous dysplasia (FD) and McCune-Albright syndrome (MAS) are rare bone and endocrine disorders in which expansile fibro-osseous lesions result in deformity, pain, and functional impairment. The effect of FD on hearing and otologic function has not been established. Objectives: To characterize audiologic and otologic manifestations in a large cohort of individuals with FD/MAS and to investigate potential mechanisms of hearing loss. Design, Setting, and Participants: In this natural history study, individuals with craniofacial FD seen at a clinical research center underwent clinical, biochemical, computed tomographic, audiologic, and otolaryngologic evaluations. Main Outcomes and Measures: Clinical and radiologic features associated with hearing loss and otologic disease were evaluated. Conductive hearing loss was hypothesized to be associated with narrowing of the external auditory canal (EAC), FD involving the epitympanum, and FD crowding the ossicular chain. Sensorineural hearing loss was hypothesized to be associated with FD affecting the internal auditory canal (IAC) and otic capsule. Results: Of the 130 study participants with craniofacial FD who were evaluated, 116 (89.2%) had FD that involved the temporal bone (median age, 19.6 years; range, 4.6-80.3 years; 64 female [55.2%]), whereas 14 (10.8%) had craniofacial FD that did not involve the temporal bone. Of the 183 ears with temporal bone FD, hearing loss was identified in 41 ears (22.4%) and was conductive in 27 (65.9%), sensorineural in 12 (29.3%), and mixed in 2 (4.9%). Hearing loss was mild and nonprogressive in most participants. Whereas EACs were narrower in ears with FD (mean difference [MD], 0.33 mm; 95% CI, 0.11-0.55 mm), this finding was associated with conductive hearing loss in only 4 participants. Fibrous dysplasia crowding of the ossicles was associated with conductive hearing loss (odds ratio [OR], 5.0; 95% CI, 2.1-11.6). The IAC length was not different between ears with and without FD (MD, -0.37; 95% CI, -0.95 to 0.211); however, canals were elongated in ears with sensorineural hearing loss (MD, -1.33; 95% CI, -2.60 to -0.07). Otic capsule involvement was noted in only 4 participants, 2 of whom had sensorineural hearing loss. Both MAS-associated growth hormone excess (OR, 3.1; 95% CI, 1.3-7.5) and neonatal hypercortisolism (OR, 11; 95% CI, 2.5-55) were associated with an increased risk of hearing loss . Conclusions and Relevance: Hearing loss in craniofacial FD is common and mild to moderate in most individuals. It typically arises from FD crowding of the ossicular chain and elongation of the IAC, whereas EAC stenosis and otic capsule invasion are less common causes. Individuals with craniofacial FD should undergo otolaryngologic evaluation and monitoring, including assessment to identify those with high-risk features.

Hearing Safety From Single- and Double-Pulse Transcranial Magnetic Stimulation in Children and Young Adults.

PURPOSE: Concerns regarding hearing safety have limited the number of studies using transcranial magnetic stimulation (TMS) in children and young adults. The objective of this study was to examine the safety of TMS with regards to hearing in a group of 16 children and young adults (17.3 ± 4.9 years) with and without brain injury. METHODS: Pure-tone hearing thresholds and distortion-product otoacoustic emissions were measured before and after exposure to single- and paired-pulse TMS (1-2 sessions of 149-446 TMS pulses at a median of 49%-100% maximum stimulator output over a 2.2 hours period). RESULTS: No mean change in hearing outcomes was noted. In addition, no clinically significant change in hearing threshold was observed in any participant, and participants did not experience a subjective change in hearing after TMS exposure. CONCLUSIONS: Single- and double-pulse TMS administered within the parameters used in this study, which included hearing protection, can be used in children and young adults without impacting hearing. This study provides further evidence for hearing safety after TMS exposure in children and young adults.

Auditory Phenotype of Smith-Magenis Syndrome.

Purpose: The purpose of this study was to describe the auditory phenotype of a large cohort with Smith-Magenis syndrome (SMS), a rare disorder including physical anomalies, cognitive deficits, sleep disturbances, and a distinct behavioral phenotype. Method: Hearing-related data were collected for 133 individuals with SMS aged 1-49 years. Audiogram data (97 participants) were used for cross-sectional and longitudinal analyses. Caregivers completed a sound sensitivity survey for 98 individuals with SMS and a control group of 24 unaffected siblings. Results: Nearly 80% of participants with interpretable audiograms (n = 76) had hearing loss, which was typically slight to mild in degree. When hearing loss type could be determined (40 participants), sensorineural hearing loss (48.1%) occurred most often in participants aged 11-49 years. Conductive hearing loss (35.2%) was typically observed in children aged 1-10 years. A pattern of fluctuating and progressive hearing decline was documented. Hyperacusis was reported in 73.5% of participants with SMS compared with 12.5% of unaffected siblings. Conclusions: This study offers the most comprehensive characterization of the auditory phenotype of SMS to date. The auditory profile in SMS is multifaceted and can include a previously unreported manifestation of hyperacusis. Routine audiologic surveillance is recommended as part of standard clinical care.

Hearing loss associated with enlarged vestibular aqueduct and zero or one mutant allele of SLC26A4.

OBJECTIVES/HYPOTHESIS: To characterize the severity and natural history of hearing loss, and the prevalence of having a cochlear implant in a maturing cohort of individuals with enlarged vestibular aqueduct (EVA) and zero or one mutant allele of SLC26A4. STUDY DESIGN: Prospective cohort study of subjects ascertained between 1998 and 2015 at the National Institutes of Health Clinical Center. METHODS: Study subjects were 127 individuals (median age, 8 years; range, 0-59 years) with EVA in at least one ear. RESULTS: Ears with EVA and zero or one mutant allele of SLC26A4 had mean 0.5/1/2/4-kHz pure-tone averages of 62.6 and 52.9 dB HL, respectively, in contrast to EVA ears with two mutant alleles of SLC26A4 (88.1 dB HL; P < .01). This association was independent of age, sex, or side of EVA (P < .001). Natural history of hearing loss was not associated with number of mutant alleles (P = .94). The prevalence of having a cochlear implant was nine (12%) of 76, two (13%) of 15, and 12 (38%) of 32 subjects with zero, one, and two mutant alleles, respectively (P = .00833). This association was not independent (P = .534) but reflected underlying correlations with age at time of first audiogram (P = .003) or severity of hearing loss (P = .000). CONCLUSIONS: Ears with EVA and zero or one mutant allele of SLC26A4 have less severe hearing loss, no difference in prevalence of fluctuation, and a lower prevalence of cochlear implantation in comparison to ears with two mutant alleles of SLC26A4. LEVEL OF EVIDENCE: NA Laryngoscope, 127:E238-E243, 2017.