Impaired long-range excitatory time scale predicts abnormal neural oscillations and cognitive deficits in Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD) is the most common form of dementia, progressively impairing cognitive abilities. While neuroimaging studies have revealed functional abnormalities in AD, how these relate to aberrant neuronal circuit mechanisms remains unclear. Using magnetoencephalography imaging we documented abnormal local neural synchrony patterns in patients with AD. To identify global abnormal biophysical mechanisms underlying the spatial and spectral electrophysiological patterns in AD, we estimated the parameters of a biophysical spectral graph model (SGM). METHODS: SGM is an analytic neural mass model that describes how long-range fiber projections in the brain mediate the excitatory and inhibitory activity of local neuronal subpopulations. Unlike other coupled neuronal mass models, the SGM is linear, available in closed-form, and parameterized by a small set of biophysical interpretable global parameters. This facilitates their rapid and unambiguous inference which we performed here on a well-characterized clinical population of patients with AD (N = 88, age = 62.73 +/- 8.64 years) and a cohort of age-matched controls (N = 88, age = 65.07 +/- 9.92 years). RESULTS: Patients with AD showed significantly elevated long-range excitatory neuronal time scales, local excitatory neuronal time scales and local inhibitory neural synaptic strength. The long-range excitatory time scale had a larger effect size, compared to local excitatory time scale and inhibitory synaptic strength and contributed highest for the accurate classification of patients with AD from controls. Furthermore, increased long-range time scale was associated with greater deficits in global cognition. CONCLUSIONS: These results demonstrate that long-range excitatory time scale of neuronal activity, despite being a global measure, is a key determinant in the local spectral signatures and cognition in the human brain, and how it might be a parsimonious factor underlying altered neuronal activity in AD. Our findings provide new insights into mechanistic links between abnormal local spectral signatures and global connectivity measures in AD.

Laryngeal Hyposensitivity in Obstructive Sleep Apnea.

INTRODUCTION: Impaired laryngopharyngeal sensation has been implicated in obstructive sleep apnea (OSA) and may play an important pathophysiological role. We evaluated sensory function in OSA by examining the laryngeal adductor reflex (LAR) response rate and temporal profile to tactile stimulation. METHODS: Laryngeal sensation testing was performed in awake adults with and without diagnosed OSA by stimulating the medial aryepiglottic fold or arytenoid using 30-mm 5-0 and 4-0 nylon Cheung-Bearelly monofilaments. Video analysis by two independent reviewers evaluated for the presence of the LAR in response to satisfactory stimuli and LAR latency to vocal fold adduction. RESULTS: Twenty-six OSA and 12 control subjects were tested with 270 satisfactory stimuli. The mean full LAR response rate to 4-0 stimulation was 38.3% in OSA vs 86.9% in control subjects (p <0.001) and to 5-0 stimulation was 27% in OSA vs 63.9% in control subjects (p <0.001). The mean LAR latency to vocal fold closure in OSA was 123.7 ms (SD 35.8) vs 156.4 ms (SD 44.3) in control (p = 0.04) subjects. OSA LAR latency was positively correlated with the apnea-hypopnea index (r = 0.30; p = 0.008). CONCLUSION: The OSA group exhibited reduced LAR response rates and shortened LAR latency, where latency was correlated with disease severity. Laryngeal hyposensitivity was affirmed and changes to LAR sensorimotor temporal dynamics were revealed. These pathophysiological alterations to the LAR may be accounted for by decreased somatosensory receptor sensitivity, increased sympathetic tone, and reorganized brain stem function in OSA. LEVEL OF EVIDENCE: 3 Laryngoscope, 2024.

Reduced neural connectivity in the caudate anterior head predicts hallucination severity in schizophrenia.

BACKGROUND: Caudate functional abnormalities have been identified as one critical neural substrate underlying sensory gating impairments that lead to auditory phantom hallucinations in both patients with schizophrenia (SZ) and tinnitus, characterized by the perception of internally generated sounds in the absence of external environmental auditory stimuli. In this study, we tested the hypothesis as to whether functional connectivity abnormalities in distinct caudate subdivisions implicated in sensory gating and auditory phantom percepts in tinnitus, which are currently being localized for neuromodulation targeting using deep brain stimulation techniques, would be associated with auditory phantom hallucination severity in SZ. METHODS: Twenty five SZ and twenty eight demographically-matched healthy control (HC) participants, completed this fMRI resting-state study and clinical assessments. RESULTS: Between-group seed-to-voxel analyses revealed only one region, the caudate anterior head, which showed reduced functional connectivity with the thalamus that survived whole-brain multiple comparison corrections. Importantly, connectivity between the caudate anterior head with thalamus negatively correlated with hallucination severity. CONCLUSIONS: In the present study, we deliver the first evidence of caudate subdivision specificity for the neural pathophysiology underlying hallucinations in schizophrenia within a sensory gating framework that has been developed for auditory phantoms in patients with tinnitus. Our findings provide transdiagnostic convergent evidence for the role of the caudate in the gating of auditory phantom hallucinations, observed across patients with SZ and tinnitus by specifying the anterior caudate division is key to mediation of hallucinations, and creating a path towards personalized treatment approaches to arrest auditory phantom hallucinations from reaching perceptual awareness.

Postoperative Complications and Neurological Deficits After Petroclival Region Meningioma Resection: A Case Series.

BACKGROUND: Surgical management of meningiomas involving the petroclival junction remains a challenge because of nearby critical neurovascular structures. OBJECTIVE: To describe surgical approach selection, outcomes, and factors associated with postoperative complications and neurological deficits in a series of patients undergoing resection of petroclival region meningiomas. METHODS: Retrospective review of patients undergoing symptomatic petroclival region meningioma resection was performed. Logistic regression was performed to identify variables associated with postoperative complications and new neurological deficits. RESULTS: Sixty-five patients underwent 54 one-stage and 11 two-stage resections with median follow-up of 51 months. Most tumors were World Health Organization grade 1 (90.8%), and the median volume was 23.9 cm 3 . Posterior petrosectomy and anterior petrosectomy were performed in 67.1% and 6.6% of operations, respectively. The gross or near total resection rate was 15.4%, and 8 patients (12.3%) progressed on follow-up. The surgical complication rate was 26.2% with no perioperative mortalities. Postoperatively, 45.8% of patients had new, persistent neurological deficits, with cranial nerves VII palsy being most common. On multivariate analysis, higher body mass index (odds ratio [OR]: 1.1, P = .04) was associated with risk of surgical complications. Longer operative time (OR: 1.4, P = .004) and staged procedures (OR: 4.9, P = .04) were associated with risk of new neurological deficit on follow-up, likely reflecting more challenging tumors. Comparing early vs later career surgeries performed by the senior author, rates of severe complications and neurological deficits decreased 23.1% and 22.3%, respectively. CONCLUSION: Petroclival region meningiomas remain surgically challenging, but improved outcomes are seen with surgeon experience. These data help inform patients on perioperative morbidity risk and provide a guide for surgical approach selection.

Differences in Hearing, Balance, and Quality-of-Life Outcomes in Petroclival Versus Nonpetroclival Posterior Fossa Meningiomas.

OBJECTIVE: To compare hearing, tinnitus, balance, and quality-of-life treatment outcomes of petroclival meningioma and nonpetroclival cerebellopontine angle meningioma cohorts. STUDY DESIGN: A retrospective cohort study of 60 patients with posterior fossa meningiomas, 25 petroclival and 35 nonpetroclival, who were treated at a single tertiary care center between 2000 and 2020. INTERVENTION: A survey battery that included the Hearing Effort of the Tumor Ear, Speech and Spatial Qualities of Hearing, Tinnitus Functional Index, Dizziness Handicap Inventory (DHI), and Short Form Health Survey. Petroclival and nonpetroclival cohorts were matched for tumor size and demographic features. MAIN OUTCOME MEASURES: Differences between groups in hearing, balance outcomes, and quality of life and patient factors that influence posttreatment quality of life. RESULTS: Petroclival meningioma patients reported poorer audiovestibular outcomes with a higher rate of deafness in the tumor ear (36.0% versus 8.6%, p = 0.032) and lower functional hearing by the Hearing Effort of the Tumor Ear, Speech and Spatial Qualities of Hearing (76.6 [6.1] versus 82.0 [4.4], p < 0.001). Current dizziness rate was higher (48.0% versus 23.5%, p = 0.05), with more severe dizziness by DHI (18.4 [4.8] versus 5.7 [2.2], p < 0.001). Both cohorts had similar high quality of life and low tinnitus severity indices. Quality-of-life Short Form Health Survey predictors were tumor size ( p = 0.012) and DHI ( p = 0.005) in multivariable analysis. CONCLUSIONS: Hearing and dizziness treatment outcomes of petroclival meningioma are poorer relative to other posterior fossa meningiomas. Despite audiovestibular outcome distinctions, the overall posttreatment quality of life was high for both petroclival and nonpetroclival meningioma.

Impaired long-range excitatory time scale predicts abnormal neural oscillations and cognitive deficits in Alzheimer's disease.

Alzheimer's disease (AD) is the most common form of dementia, progressively impairing memory and cognition. While neuroimaging studies have revealed functional abnormalities in AD, how these relate to aberrant neuronal circuit mechanisms remains unclear. Using magnetoencephalography imaging we documented abnormal local neural synchrony patterns in patients with AD. To identify abnormal biophysical mechanisms underlying these abnormal electrophysiological patterns, we estimated the parameters of a spectral graph-theory model (SGM). SGM is an analytic model that describes how long-range fiber projections in the brain mediate the excitatory and inhibitory activity of local neuronal subpopulations. The long-range excitatory time scale was associated with greater deficits in global cognition and was able to distinguish AD patients from controls with high accuracy. These results demonstrate that long-range excitatory time scale of neuronal activity, despite being a global measure, is a key determinant in the spatiospectral signatures and cognition in AD.

Multi-tasking deep network for tinnitus classification and severity prediction from multimodal structural MR images.

Objective:Subjective tinnitus is an auditory phantom perceptual disorder without an objective biomarker. Fast and efficient diagnostic tools will advance clinical practice by detecting or confirming the condition, tracking change in severity, and monitoring treatment response. Motivated by evidence of subtle anatomical, morphological, or functional information in magnetic resonance images of the brain, we examine data-driven machine learning methods for joint tinnitus classification (tinnitus or no tinnitus) and tinnitus severity prediction.Approach:We propose a deep multi-task multimodal framework for tinnitus classification and severity prediction using structural MRI (sMRI) data. To leverage complementary information multimodal neuroimaging data, we integrate two modalities of three-dimensional sMRI-T1 weighted (T1w) and T2 weighted (T2w) images. To explore the key components in the MR images that drove task performance, we segment both T1w and T2w images into three different components-cerebrospinal fluid, grey matter and white matter, and evaluate performance of each segmented image.Main results:Results demonstrate that our multimodal framework capitalizes on the information across both modalities (T1w and T2w) for the joint task of tinnitus classification and severity prediction.Significance:Our model outperforms existing learning-based and conventional methods in terms of accuracy, sensitivity, specificity, and negative predictive value.

A Smartphone Application and Education Program for Hearing Health Promotion in High School Teenagers.

OBJECTIVES: To assess knowledge retention after video-based hearing health education and measure headphone listening behavior change using a novel smartphone application. METHODS: In this prospective longitudinal study, students participated in video-based hearing health education and hearing screening sessions. Hearing health knowledge was assessed in students and parents after 6 weeks. A novel smartphone application was created to measure daily noise exposure based on volume settings with headphone use and to display the National Institute for Occupational Safety and Health (NIOSH) noise doses with alerts for cumulative daily doses nearing the maximum. RESULTS: Seventy-six teenage students and parents participated. Eighty three percent of participants identified as a racial or ethnic minority and 66% were of low-income socioeconomic status. Hearing health knowledge was retained in students 6 weeks after education and parents' knowledge improved from baseline. The smartphone app was installed on 12 student phones, and 25% of days monitored exhibited noise doses that exceeded the NIOSH maximum. App use for at least 10 days by nine students showed a significant reduction in average daily noise dose and time spent at the highest volume settings during the second-half of app use. CONCLUSIONS: Video-based hearing health education with knowledge question reinforcement was associated with knowledge retention in students and improved parental attitudes and knowledge about hearing conservation. A smartphone app with a real-time display of headphone cumulative noise exposure dose identified at-risk students. The integration of hearing health education, hearing screening, and digital health tools has promised to promote positive behavior changes for long-term hearing conservation. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:2007-2013, 2023.

Treated large posterior fossa vestibular schwannoma and meningioma: Hearing outcome and willingness-to-accept brain implant for unilateral deafness.

Background/Objective: To compare functional hearing and tinnitus outcomes in treated large (~ 3 cm) vestibular schwannoma (VS) and posterior fossa meningioma cohorts, and construct willingness-to-accept profiles for an experimental brain implant to treat unilateral hearing loss. Methods: A two-way MANOVA model with two independent variables (tumor type; time from treatment) and three dependent variables (hearing effort of tumor ear; abbreviated Speech, Spatial, and Qualities of Hearing scale (SSQ12); Tinnitus Functional Index (TFI)) was used to analyze data from VS (N = 32) and meningioma (N = 50) patients who were treated at a tertiary care center between 2010 and 2020. A query to probe acceptance of experimental treatment for hearing loss relative to expected benefit was used to construct willingness-to-accept profiles. Results: Tumor type was statistically significant on the combined dependent variables analysis (F[3, 76] = 19.172, p < .0005, Wilks' Λ = 0.569). Meningioma showed better outcome for hearing effort (F[1, 76] = 14.632, p < .0005) and SSQ12 (F[1, 76] = 16.164, p < .0005), but not for TFI (F[1, 76] = 1.247, p = .268) on univariate two-way ANOVA analyses. Superior hearing effort and SSQ12 indices in the short-term (< 2 years) persisted in the long-term (> 2 years) (p ≤ .017). At the 60% speech understanding level, 77% of respondents would accept an experimental brain implant. Conclusion: Hearing outcome is better for posterior fossa meningioma compared to VS. Most patients with hearing loss in the tumor ear would consider a brain implant if the benefit level would be comparable to a cochlear implant. Level of Evidence: 2.

Striatal networks for tinnitus treatment targeting.

Neuromodulation treatment effect size for bothersome tinnitus may be larger and more predictable by adopting a target selection approach guided by personalized striatal networks or functional connectivity maps. Several corticostriatal mechanisms are likely to play a role in tinnitus, including the dorsal/ventral striatum and the putamen. We examined whether significant tinnitus treatment response by deep brain stimulation (DBS) of the caudate nucleus may be related to striatal network increased functional connectivity with tinnitus networks that involve the auditory cortex or ventral cerebellum. The first study was a cross-sectional 2-by-2 factorial design (tinnitus, no tinnitus; hearing loss, normal hearing, n = 68) to define cohort level abnormal functional connectivity maps using high-field 7.0 T resting-state fMRI. The second study was a pilot case-control series (n = 2) to examine whether tinnitus modulation response to caudate tail subdivision stimulation would be contingent on individual level striatal connectivity map relationships with tinnitus networks. Resting-state fMRI identified five caudate subdivisions with abnormal cohort level functional connectivity maps. Of those, two connectivity maps exhibited increased connectivity with tinnitus networks-dorsal caudate head with Heschl's gyrus and caudate tail with the ventral cerebellum. DBS of the caudate tail in the case-series responder resulted in dramatic reductions in tinnitus severity and loudness, in contrast to the nonresponder who showed no tinnitus modulation. The individual level connectivity map of the responder was in alignment with the cohort expectation connectivity map, where the caudate tail exhibited increased connectivity with tinnitus networks, whereas the nonresponder individual level connectivity map did not.

Posterior petrous face meningiomas presenting with Ménière's-like syndrome: a case series and review of the literature.

OBJECTIVE: Ménière's disease is an inner ear disorder classically characterized by fluctuating hearing loss, tinnitus, and aural fullness accompanied by episodic vertigo. While the pathogenesis of Ménière's remains under debate, histopathological analyses implicate endolymphatic sac dysfunction with inner ear fluid homeostatic dysregulation. Little is known about whether external impingement of the endolymphatic sac by tumors may present with Ménière's-like symptoms. The authors present a case series of 7 patients with posterior fossa meningiomas that involved the endolymphatic sac and new onset of Ménière's-like symptoms and review the literature on this rare clinical entity. METHODS: A retrospective review of patients undergoing resection of a posterior petrous meningioma was performed at the authors' institution. Inclusion criteria were age older than 18 years; patients presenting with Ménière's-like symptoms, including episodic vertigo, aural fullness, tinnitus, and/or hearing loss; and tumor location overlying the endolymphatic sac. RESULTS: There were 7 cases of posterior petrous face meningiomas involving the vestibular aperture presenting with Ménière's-like symptoms. Imaging and intraoperative examination confirmed no cranial nerve VIII compression or labyrinthine artery involvement accounting for audiovestibular symptoms. Of the 7 patients in the series, 6 experienced significant improvement or resolution of their vertigo, and all 7 had improvement or resolution of their tinnitus after resection. Of the 5 patients who had preoperative hearing loss, 2 experienced improvement or resolution of their ipsilateral preoperative hearing deficit, whereas the other 3 had unchanged hearing loss compared to preoperative evaluation. CONCLUSIONS: Petrous face meningiomas overlying the endolymphatic sac can present with a Ménière's syndrome. Early recognition and microsurgical excision of these tumors is critical for resolution of most symptoms and stabilization of hearing loss.

Aesthesiometer-Based Testing for Laryngopharyngeal Hyposensitivity.

OBJECTIVES/HYPOTHESIS: To develop a method for threshold estimation of the laryngeal adductor reflex (LAR) response using Cheung-Bearelly monofilaments. STUDY DESIGN: Cross-sectional. METHODS: Twenty-two healthy adults (12 men, 10 women) were tested for LAR response outcome using 30 mm 5-0 and 4-0 nylon monofilaments. Tactile stimuli were delivered to the aryepiglottic (AE) fold and medial pyriform sinus (MPS). Dichotomous classifier features and performance (area under the curve (AUC)), the LAR response outcome agreement and disagreement matrix, and test-retest reliability were examined. From those data, a test protocol that would minimize patient burden to estimate the LAR triggering threshold was formulated. RESULTS: Classifier performance of 5-0 monofilament stimulation of the AE fold (sensitivity = 0.63, specificity = 0.63, PPV = 0.74, NPV = 0.25) and MPS (sensitivity = 0.45, specificity = 0.77, PPV = 0.74, NPV = 0.23,) was slightly below that of 4-0 monofilament stimulation of the AE fold (sensitivity = 0.82, specificity = 0.50, PPV = 0.82, NPV = 0.50) and MPS (sensitivity = 0.84, specificity = 0.64, PPV = 0.90, NPV = 0.56), based on AUC. LAR response outcome agreement for 5-0 and 4-0 stimulations was high (93%) for 5-0 positive response, but low (29%) for 5-0 negative response. Aesthesiometer test-retest reliability for LAR response outcome was excellent (Cronbach's alpha = 0.97). CONCLUSIONS: Threshold estimation of the LAR response may be operationalized by adopting a decision tree protocol. For negative LAR response to initial 5-0 monofilament stimulation and positive response to subsequent 4-0 monofilament stimulation, the higher threshold is confirmed. Positive LAR response to 5-0 or 4-0 monofilament stimulation is expected in over 90% of asymptomatic adults. Negative LAR response to 4-0 monofilament stimulation identifies patients at risk for laryngopharyngeal hyposensitivity. LEVEL OF EVIDENCE: 3b Laryngoscope, 132:163-168, 2022.

Laryngeal Adductor Reflex Movement Latency Following Tactile Stimulation.

OBJECTIVE: To measure the latency of laryngeal adductor reflex (LAR) motion onset at 2 laryngopharyngeal subsites using calibrated aesthesiometers. STUDY DESIGN: Cross-sectional. SETTING: Academic institution. METHODS: Twenty-one asymptomatic, healthy subjects (11 male, 10 female) underwent laryngopharyngeal sensory testing with tactile stimuli delivered to the aryepiglottic fold and medial pyriform sinus using 30-mm Cheung-Bearelly monofilaments (4-0 and 5-0 nylon sutures) via channeled flexible laryngoscope. The LAR onset latency, defined as the first visual detection of ipsilateral vocal fold adduction following tactile stimulation, was measured with frame-by-frame analysis of video recordings. RESULTS: The overall mean LAR latency across both subsites and stimulation forces was 176.6 (95% CI, 170.3-183.0) ms, without significant difference between subsites or forces. The critical value for LAR response latency prolongation at the .01 significance level was 244 ms. At 30 frames/s video capture resolution, LAR response latency ≥8 frame intervals would indicate abnormal prolongation. CONCLUSION: Aesthesiometer-triggered LAR latency appears to be invariant over an 8.7-dB force range and between the aryepiglottic fold and medial pyriform sinus subsites in controls. Laryngeal adductor reflex latency incongruences between stimulation forces or laryngopharyngeal subsites may serve as pathophysiological features to dissect mechanisms of upper aerodigestive tract disorders. LEVEL OF EVIDENCE: Level 3B.

Interhemispheric Auditory Cortical Synchronization in Asymmetric Hearing Loss.

OBJECTIVES: Auditory cortical activation of the two hemispheres to monaurally presented tonal stimuli has been shown to be asynchronous in normal hearing (NH) but synchronous in the extreme case of adult-onset asymmetric hearing loss (AHL) with single-sided deafness. We addressed the wide knowledge gap between these two anchoring states of interhemispheric temporal organization. The objectives of this study were as follows: (1) to map the trajectory of interhemispheric temporal reorganization from asynchrony to synchrony using magnitude of interaural threshold difference as the independent variable in a cross-sectional study and (2) to evaluate reversibility of interhemispheric synchrony in association with hearing in noise performance by amplifying the aidable poorer ear in a repeated measures, longitudinal study. DESIGN: The cross-sectional and longitudinal cohorts were comprised of 49 subjects (AHL; N = 21; 11 male, 10 female; mean age = 48 years) and NH (N = 28; 16 male, 12 female; mean age = 45 years). The maximum interaural threshold difference of the two cohorts spanned from 0 to 65 dB. Magnetoencephalography analyses focused on latency of the M100 peak response from auditory cortex in both hemispheres between 50 msec and 150 msec following monaural tonal stimulation at the frequency (0.5, 1, 2, 3, or 4 kHz) corresponding to the maximum and minimum interaural threshold difference for better and poorer ears separately. The longitudinal AHL cohort was drawn from three subjects in the cross-sectional AHL cohort (all male; ages 49 to 60 years; varied AHL etiologies; no amplification for at least 2 years). All longitudinal study subjects were treated by monaural amplification of the poorer ear and underwent repeated measures examination of the M100 response latency and quick speech in noise hearing in noise performance at baseline, and postamplification months 3, 6, and 12. RESULTS: The M100 response peak latency values in the ipsilateral hemisphere lagged those in the contralateral hemisphere for all stimulation conditions. The mean (SD) interhemispheric latency difference values (ipsilateral less contralateral) to better ear stimulation for three categories of maximum interaural threshold difference were as follows: NH (≤ 10 dB)-8.6 (3.0) msec; AHL (15 to 40 dB)-3.0 (1.2) msec; AHL (≥ 45 dB)-1.4 (1.3) msec. In turn, the magnitude of difference values were used to define interhemispheric temporal organization states of asynchrony, mixed asynchrony and synchrony, and synchrony, respectively. Amplification of the poorer ear in longitudinal subjects drove interhemispheric organization change from baseline synchrony to postamplification asynchrony and hearing in noise performance improvement in those with baseline impairment over a 12-month period. CONCLUSIONS: Interhemispheric temporal organization in AHL was anchored between states of asynchrony in NH and synchrony in single-sided deafness. For asymmetry magnitudes between 15 and 40 dB, the intermediate mixed state of asynchrony and synchrony was continuous and reversible. Amplification of the poorer ear in AHL improved hearing in noise performance and restored normal temporal organization of auditory cortices in the two hemispheres. The return to normal interhemispheric asynchrony from baseline synchrony and improvement in hearing following monoaural amplification of the poorer ear evolved progressively over a 12-month period.

Short-term chemosensory distortions and phantoms in COVID-19.

Objective: To identify differentiation features of chemosensory dysfunction in COVID-19 infection and their primary drivers. Study Design: Cross-sectional cohort comparison. Methods: A national anonymous survey was used to query participants regarding nasal symptoms and chemosensory dysfunction including sensitivity levels, and presence or absence of distortions and phantoms within the 6-week time window surrounding their COVID-19 testing and survey completion. Results: Three-hundred and sixty-four respondents who reported COVID-19 positive (COVID+; n = 176) or COVID-19 negative (COVID-; n = 188) test results completed the survey. The COVID+ cohort had higher occurrence rates for: (a) chemosensory sensitivity impairments (67.0% vs 30.3%; P < .01), where the rate of complete loss of smell (anosmia) or taste (ageusia) was higher (35.8% vs 4.8%; P < .01), and (b) chemosensory distortions (39.8% vs 19.1%; P < .01), where the rate of anosmia or ageusia with distortions was also higher in the COVID+ cohort (19.9% vs 2.7%; P < .01). Occurrence rates in the two cohorts were similar for chemosensory phantoms (COVID+ 17.0%, COVID- 18.6%; P = .70) and nasal discharge or stuffiness in the presence of sensitivity impairment (COVID+ 63.6%, COVID- 52.6%; P = .17). Conclusion: Chemosensory dysfunction in COVID-19 is associated with higher rates of smell or taste sensitivity impairments and distortions. Higher rates of anosmia and ageusia drive these key findings. Chemosensory phantoms and nasal symptoms in the presence of sensitivity impairment occur at rates that should demand clinical attention, but they do not appear to be specific to COVID-19 positivity. Level of Evidence: 2b.

Neuroanatomic Volume Differences in Tinnitus and Hearing Loss.

OBJECTIVES: To investigate neuroanatomic volume differences in tinnitus and hearing loss. STUDY DESIGN: Cross-sectional. METHODS: Sixteen regions of interest (ROIs) in adults (43 male, 29 female) were examined using 3Tesla structural magnetic resonance imaging in four cohorts: 1) tinnitus with moderate hearing loss (N = 31), 2) moderate hearing loss only (N = 15), 3) tinnitus with normal hearing (N = 17), and 4) normal hearing only (N = 13). ROI volumes were corrected for brain size, age, and sex variations. Analysis of covariance (ANCOVA) and post hoc Tukey's test were used to isolate the effects of tinnitus and hearing loss on volume differences. Effect sizes were calculated as the fraction of total variance (η2 ) in ANCOVA models and percent of mean volume difference relative to mean total volume. RESULTS: The four cohort ANCOVA revealed tinnitus and hearing loss cohorts to have increased volume in the corona radiata (η2  = 0.192; P = .0018) and decreased volume in the nucleus accumbens (η2  = 0.252; P < .0001), caudate nucleus (η2  = 0.188; P = .002), and inferior fronto-occipital fasciculus (η2  = 0.250; P = .0001). Tinnitus with normal hearing showed decreased volume in the nucleus accumbens (22.0%; P = .001) and inferior fronto-occipital fasciculus (18.1%; P = .002), and hearing loss only showed increased volume in the corona radiata (10.7%; P = .01) and decreased volume in the nucleus accumbens (22.1%; P = .001), caudate nucleus (16.1%; P = .004), and inferior fronto-occipital fasciculus (18.3%; P = .003). CONCLUSION: Tinnitus and hearing loss have overlapping effects on neurovolumetric alterations, especially impacting the nucleus accumbens and inferior fronto-occipital fasciculus. Neurovolumetric studies on tinnitus or hearing loss can be more complete by accounting for those two clinical dimensions separately and jointly. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:1863-1868, 2021.

Novel Adaptation of a Validated Tactile Aesthesiometer to Evaluate Laryngopharyngeal Sensation.

OBJECTIVES: To evaluate laryngopharyngeal sensation at specific subsites using a novel adaptation of a buckling force aesthesiometer for delivery of calibrated tactile stimuli. STUDY DESIGN: Cross-sectional. METHODS: Twenty-two healthy adults (12 men, 10 women) were tested for responses to tactile forces, using 30-mm 6-0, 5-0, and 4-0 nylon monofilaments to map sensation of the aryepiglottic (AE) fold, lateral pyriform sinus (PS), and medial PS bilaterally. The outcome measures were the laryngeal adductor reflex (LAR) and patient reported rating of perceptual strength. RESULTS: Rates of triggered LAR response grew monotonically with increasing tactile force at a mean (SD) stimulus duration of 663 (164) msec across all three subsites. The AE fold and medial PS had similar profiles and were the most responsive, while the lateral PS was the least responsive. Low force (6-0) response rate was ≤14% for all subsites. High force (4-0) response rate was 91% for AE fold and medial PS, and 23% for lateral PS. The perceptual strength gradient was in the lateral to medial trajectory. CONCLUSION: Normative data for LAR response rates to low, medium, and high stimulation forces will be useful to assess sensory dysfunction in a variety of laryngopharyngeal disorders, including aspiration, dysphagia, chronic cough, and spasmodic dysphonia. In turn, that information will guide the creation of innovative treatments. LAR response profiles to low and high force stimuli will inform the development of screening tools to diagnose laryngopharyngeal hypersensitivity and hyposensitivity conditions. LEVEL OF EVIDENCE: 3b Laryngoscope, 131:1324-1331, 2021.

Temporal Profile of Olfactory Dysfunction in COVID-19.

OBJECTIVE: Coronavirus disease 2019 (COVID-19) is associated with olfactory dysfunction, but the evolution of the olfactory loss and timeline to recovery are largely unknown. This study examines changes in smell sensitivity in COVID-19-positive (COVID+) and COVID-19-negative (COVID-) viral illness during the initial weeks after infection. STUDY DESIGN: Cross-sectional cohort comparison. SETTING: National anonymous surveys. METHODS: Survey participants were queried about smell sensitivity and general health status at the time of COVID-19 testing and in the weeks that followed. RESULTS: In total, 375 (174 COVID+, 201 COVID-) participants completed the survey and 132 (62 COVID+, 70 COVID-) participants completed the 2-week follow-up survey. Normal smell in the COVID+ cohort was less frequent at the time of testing and at follow up (P < .05). Dynamic changes in smell sensitivity in the COVID+ cohort were more frequent in the initial weeks (P < .001). In those with normosmia at the start of infection, 38% of the COVID+ cohort reported worsening smell compared to only 8% in the COVID- cohort (P < .05). Recovery of overall health was associated with normosmia at the time of infection and improvement of smell sensitivity within weeks of infection. CONCLUSION: The COVID+ cohort showed greater dynamic change in smell sensitivity and a higher rate of persistent olfactory dysfunction in the weeks after infection. Normal smell at the time of COVID-19 infection may still worsen before recovery. Overall health recovery after viral illness is associated with improvement in smell sensitivity and the absence of initial anosmia or hyposmia.

Ear Preference and Interaural Threshold Asymmetry.

OBJECTIVE: To define the relationships among ear preference strength, audiometric interaural asymmetry magnitude, and hearing impairment. STUDY DESIGN: Prospective, cross-sectional. SETTING: Academic audiology clinic. PATIENTS: Adults. INTERVENTIONS: Diagnostic. MAIN OUTCOME MEASURES: Patient-reported ear preference strength using a seven-category preference (no preference; left or right somewhat, strongly, or completely) scheme, hearing disability level on the Speech, Spatial, and Qualities of Hearing scale, and audiometric interaural threshold asymmetry were analyzed in three study cohorts: 1) normal hearing (thresholds ≤ 25 dB, n = 66), 2) symmetric hearing loss (any single threshold > 25 dB, n = 81), and 3) asymmetric hearing loss (maximum average interaural threshold difference at any two adjacent frequencies (IThrDmax2)≥ 15 dB, n = 112). RESULTS: Receiver operating characteristic curves for somewhat, strongly, and completely ear preference levels using IThrDmax2 cutoff values at 15, 30, and 45 dB showed good to excellent classifier performance (all curve areas ≥ 0.84). The mapping of ear preference strength to the most likely IThrDmax2 range by odds ratio analysis demonstrated: no preference (< 15 dB), somewhat (15-29 dB), strongly (30-44 dB), and completely (≥ 45 dB). Complete dependence on one ear was associated with the most severe degradation in spatial hearing function. CONCLUSION: Categorical ratings of ear preference strength may be mapped to ranges of audiometric threshold asymmetry magnitude and spatial hearing disability level. Querying ear preference strength in routine clinical practice would enable practitioners to identify patients with asymmetric hearing more expeditiously and promote timely evaluation and treatment.