Changes In Threshold Research Articles

Cortical bone total ossicular graft supported with crescent-shaped cartilage.

This study aimed to compare the hearing outcomes of patients who underwent different type 4 tympanoplasty techniques. Patients who underwent tympanoplasty for chronic otitis media and were treated with cortical bone total ossicular prosthesis supported with crescent-shaped cartilage (Group 1), cortical bone total ossicular prosthesis (Group 2) and titanium total ossicular prosthesis (Group 3) were included in the study. Hearing outcomes were evaluated and compared with audiological tests performed before and at least 1 year after surgery. There were 12 patients in Group 1 (6 males and 6 females), 14 patients in Group 2 (6 males and 8 females) and 18 patients in Group 3 (10 males and 8 females). After reconstruction, the air conduction threshold changed from 56.83 ± 13.63 to 32.25 ± 13.55dB in Group 1, from 57.43 ± 15.3 to 40.07 ± 18.8dB in Group 2 and from 55.39 ± 15.59 to 42.22 ± 17.32dB in Group 3. Air-bone gap (ABG) changed from 37.58 ± 9.56 to 15.08 ± 9.58dB in Group 1, from 36.71 ± 10.84 to 21.07 ± 11.16dB in Group 2 and from 34.5 ± 11.72 to 22.28 ± 10.13dB in Group 3. Preoperative and postoperative outcomes of all three groups in terms of both air conduction threshold and air-bone gap were significantly different (p < 0.01). Preoperative and postoperative changes in air conduction threshold of the three groups were also significantly different (p = 0.037). However, the differences among the three groups in terms of preoperative and postoperative changes in ABG were not significant (p = 0.057). Cortical bone supported with crescent-shaped cartilage total ossicular prosthesis had better hearing outcomes than other groups.

Thresholds for conjugated hyperbilirubinaemia and hepatobiliary scintigraphy in biliary atresia: A 12-year national follow-up.

To investigate liver biochemistry in infants screened for biliary atresia (BA) at the time of hepatobiliary scintigraphy (HS) and to evaluate the effect of change in threshold for HS. Infants born from 2010 to 2021, who underwent HS <6 months postpartum for BA, were included and data sourced from electronic medical records. The change in threshold in 2018 from ≥20 (and/or if conjugated bilirubin exceeds 20% of total bilirubin) to ≥17 μM (regardless of total bilirubin) was evaluated. In the cohort of 635 infants, 48 had BA, 247 had AATD, and the remaining 343 were categorised as 'other'. After the threshold adjustment, HS timing was unaffected (p = 0.27), but the annual HS rate rose from 39 to 87, yet evaluations following the new guideline only accounted for 12%. All liver parameters were elevated in the BA group compared with the additional groups (p < 0.001). Amongst the 104 patients with non-excretory HS, gamma-glutamyl transferase (p < 0.001) and alanine aminotransferase (p = 0.002) remained elevated for BA. The lowest conjugated bilirubin measured in BA children was 36 μM. After threshold change, HS use increased without earlier BA diagnostics, but most were not due to the new guideline. Alanine aminotransferase and gamma-glutamyl transferase should be considered in BA diagnostics.

Threshold changes in the production potential of bush clumps along piosphere gradients in arid thicket mosaics

Various studies have noted threshold changes in vegetation composition and structure and soil physical and chemical properties in the Albany Thicket biome of South Africa. The aim of this study is to assess if these changes to the environment have transformed the ecosystem’s forage production potential. To estimate forage production potential we compare three models that make use of the mean and variance of the Normalized Difference Vegetation Index (NDVI) obtained from two WorldView-2 satellite images. For the models, NDVI values were sampled along four independent piosphere gradients that vary in their intensity of use and rest from herbivory. Our results indicate that the model that makes use of NDVI variance after a good rainfall year is able to discern changes in the forage production potential that corroborate threshold changes in the vegetation and soil environment. Our results support the growing body of evidence that increases in the variance of ecosystem processes and services are important indicators of impending threshold changes in social-ecological systems.

Characterization of aroma differences in Jiangxiangxing baijiu with varying ethanol concentrations: Emphasis on olfactory threshold changes of aroma compounds

Characterization of aroma differences in Jiangxiangxing baijiu with varying ethanol concentrations: Emphasis on olfactory threshold changes of aroma compounds

Pentosan Polysulfate Maculopathy: Final Outcomes from a 4-Year Prospective Study of Disease Progression after Drug Cessation.

To report the long-term disease course of pentosan polysulfate (PPS) maculopathy following drug cessation. Single-institution, prospective case series. 23 eyes of 12 participants seen at the Emory Eye Center with a diagnosis of PPS maculopathy were included in our study. Participants were enrolled between December 1, 2018, and December 1, 2019, and data were collected annually for four years. Changes in visual function and structure were the primary outcomes measured. Visual function was assessed using Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity (BCVA), ETDRS low-luminance visual acuity (LLVA), Minnesota low-vision reading (MNREAD) performance, contrast sensitivity, mesopic and scotopic microperimetry, and dark adaptometry. Patient reported outcomes were assessed with the National Eye Institute Visual Function Questionnaire (NEI-VFQ-39) and Low Luminance Questionnaire (LLQ). Structural outcomes included the presence of complete retinal pigment epithelium and outer retinal atrophy (cRORA), atrophic lesion size (in mm2), macular central subfield thickness (CST), and subfoveal choroidal thickness (SFCT). Of the 12 participants, 11 (91.7%) were female, with a median age at enrollment of 58 years. The median ETDRS BCVA letter score at baseline was 83, with a median change of -5 letters over 4 years (P = 0.005). The median 4-year change in mesopic microperimetry average threshold and percent reduced threshold was -5.4 dB (P = 0.003) and 48.6% (P = 0.004), respectively. MNREAD performance (assessed at 2 and 4 years) declined across all measures, with a median maximum reading speed change of -21 words per minute (P = 0.007). NEI-VFQ-39 and LLQ composite scores significantly decreased over 4 years. At baseline, 9 eyes (39%) had macular cRORA. By the study's end, 5 of the remaining eyes (35.7%) developed new-onset cRORA. The median linearized growth rate of atrophic lesions was 0.23 mm/year. The median 4-year change of CST and SFCT was -7.0 μm (P = 0.055) and -22.0 μm (P = 0.610), respectively. This prospective study demonstrates continued progression of broad-ranging functional and structural deficits in PPS maculopathy long after drug cessation. These findings should inform PPS prescribing patterns, patient counseling, and disease monitoring strategies.

Repeated low-intensity noise exposure exacerbates age-related hearing loss via RAGE signaling pathway.

Repeated low-intensity noise exposure is prevalent in industrialized societies. It has long been considered risk-free until recent evidence suggests that the temporary threshold shift (TTS) induced by such exposure might be a high-risk factor for hearing loss. This study was conducted to further investigate the manner in which repeated low-intensity noise exposure contributed to hearing damage. Two-month-old C57BL/6 J mice were exposed to white noise at 96 dB SPL for 8 h per day over 7 days to induce TTS. Auditory brainstem response (ABR) was monitored to assess changes in hearing thresholds, tracking the effects of noise exposure until the mice reached 12 months of age. Our results indicated that noise-exposed mice exhibited accelerated age-related hearing loss spanning from high to low frequencies. Proteomics analysis revealed an upregulation in the receptor for the advanced glycation end-products (RAGE) signaling pathway, which was associated with an activated inflammatory response, vascular injury, and mitochondrial and synaptic dysfunction. Further analysis confirmed increased levels of inflammatory cytokines in the cochlear lymph fluid and significant macrophages infiltration in the cochlear lateral wall, accompanied by hyperpermeability of the blood-labyrinth barrier. Additionally, degenerated mitochondria in the outer hair cells and decreased synaptic ribbons in the inner hair cells were also observed. These pathological changes indicated that noise exposure damages the cochlear cellular components, increasing the cochlear susceptibility to age-related stress. Our findings suggest that TTS caused by repeated low-intensity noise exposure correlates with a severe sensorineural hearing loss during aging; targeting the RAGE signaling pathway could be a promising strategy to mitigate damage from low-intensity noise and slow down the progression of age-related hearing loss.

Linear stability analysis in channel with slippery and rough boundaries

This study examines two-dimensional flow stability in a channel with a superhydrophobic wall and small amplitude roughness. We consider two primary cases: (1) the upper surface is smooth and allows slip, while the lower surface is rough and has no slip; and (2) both surfaces exhibit slip behavior. By using the orthogonal modal method for the Orr–Sommerfeld equation, we rigorously assess the flow's linear stability. The results demonstrate that the slip coefficient and rough wave number significantly influence stability characteristics. Variations in the slip coefficient lead to notable changes in stability thresholds, while the rough wave number alters the flow's response to perturbations. These findings enhance our understanding of the interactions between fluid dynamics, surface properties, and stability phenomena in channels, providing valuable insights for optimizing flow control strategies and designing surfaces in various engineering applications.

Tonic Cold Pain Temporal Summation and Translesional Cold Pressor Test-Induced Pronociception in Spinal Cord Injury: Association with Spontaneous and Below-Level Neuropathic Pain.

Background/Objectives: Although increased nociceptive excitability and deficient endogenous pain modulation are considered key features of pronociception and central sensitization, their contribution to neuropathic pain (NP) characteristics in SCI is unclear. The aim of this study was to characterize tonic cold perception and endogenous pain modulation in individuals with and without SCI-NP, considering the stage and severity of SCI and, secondarily, NP phenotype. Methods: Temporal summation of pain (TSP) and neuropathic features were assessed using the numerical rating scale (NRS) and Douleur Neuropathique 4 screening questionnaire (DN4) during the tonic cold pressor test (CPT, 12 °C 60 s) applied to the dominant hand and foot. CPT-induced pronociception was assessed as change in algometer pressure pain thresholds (PPTs) measured at the V2, C6, and L4 dermatomes. Results: A total of 72 individuals were recruited (age-sex-matched noninjured, n = 24; SCI-NP, n = 24; SCI-noNP, n = 24 [AIS A: n = 12, AIS B-D: n = 12; subacute SCI: n = 12, chronic SCI: n = 12]). TSP in response to the foot CPT was higher in subacute compared to chronic incomplete SCI-NP, while TSP to the hand CPT was significantly higher in chronic compared to the subacute complete SCI-NP group. Evoked pain intensity during the hand CPT correlated with duration of below-level SCI-NP. The hand CPT induced widespread pronociception (lower PPT), which correlated with 7-day non-evoked (spontaneous) pain intensity in individuals with incomplete SCI-NP. Individuals with below-level NP, but not at-level NP, showed higher TSP during the foot CPT and greater hand CPT-induced L4 dermatome pronociception. Conclusions: Collectively, measurements of above and below-level temporal summation of pain and translesional-induced pronociception in the SCI-NP group highlight the role of these mechanisms in widespread central sensitization, spontaneous pain intensity, and spinothalamic tract hyperexcitability, especially in individuals diagnosed with below-level NP.

Regulatory T cells require peripheral CCL2-CCR2 signaling to facilitate the resolution of medication overuse headache-related behavioral sensitization

BackgroundMedication overuse headache (MOH) is the most common secondary headache disorder, resulting from chronic and excessive use of medication to treat headaches, for example, sumatriptan. In a recent study, we have shown that the peripheral C-C motif ligand 2 (CCL2), C-C motif chemokine receptor 2 (CCR2) and calcitonin-gene-related peptide (CGRP) signaling pathways interact with each other and play critical roles in the development of chronic migraine-related behavioral and cellular sensitization. In the present study, we investigated whether CCL2-CCR2 and CGRP signaling pathways play a role in the development of sumatriptan overuse-induced sensitization, and whether they are involved in its resolution by the low-dose interleukin-2 (LD-IL-2) treatment.MethodsMice received daily sumatriptan administration for 12 days. MOH-related behavioral sensitization was assessed by measuring changes of periorbital mechanical thresholds for 3 weeks. CCL2-CCR2 and CGRP signaling pathways were inhibited by targeted gene deletion or with an anti-CCL2 antibody. Ca2+-imaging was used to examine whether repetitive sumatriptan treatment enhances CGRP and pituitary adenylate cyclase–activating polypeptide (PACAP) signaling in trigeminal ganglion (TG) neurons. LD-IL-2 treatment was initiated after the establishment of sumatriptan-induced sensitization. Immunohistochemistry and flow cytometry analyses were used to examine whether CCL2-CCR2 signaling controls regulatory T (Treg) cell proliferation and/or trafficking.ResultsCCL2, CCR2 and CGRPα global KO mice exhibited robust sumatriptan-induced behavioral sensitization comparable to wild-type controls. Antibody neutralization of peripheral CCL2 did not affect sumatriptan-induced behaviors either. Repeated sumatriptan administration did not enhance the strength of CGRP or PACAP signaling in TG neurons. Nevertheless, LD-IL-2 treatment, which facilitated the resolution of sumatriptan-induced sensitization in wild-type and CGRPα KO mice, was completely ineffective in mice with compromised CCL2-CCR2 signaling. In CCL2 KO mice, we observed normal LD-IL-2-induced Treg expansion in peripheral blood, but the increase of Treg cells in dura and TG tissues was significantly reduced in LD-IL-2-treated CCL2 KO mice relative to wild-type controls.ConclusionsThese results indicate that the endogenous CCL2-CCR2 and CGRP signaling pathways are not involved in sumatriptan-induced behavioral sensitization, suggesting that distinct molecular mechanisms underlie chronic migraine and MOH. On the other hand, peripheral CCL2-CCR2 signaling is required for LD-IL-2 to reverse chronic headache-related sensitization.Graphical abstract

Optimizing the Automated Analysis of Inorganic Gunshot Residue Particles by SEM-EDX: From Synthetic Particle Standards to More Time-Efficient Settings for Daily Casework

Gunshot residues deposited on all surfaces in the nearest vicinity of the shooting incident, when revealed, can contribute to the explanation of various aspects of such an incident for forensic purposes. Examinations of gunshot residue, mainly inorganic particles, at forensic laboratories are expected to be reliable and fast. This primarily depends on the performance of the used scanning electron microscope integrated with an energy dispersive X-ray spectrometer and the automatic program searching for particles of defined characteristics. Among the milestones on the pathway towards quality assurance in examinations of gunshot particles, the invention of the synthetic gunshot residue specimen ought to be named. Such a specimen with particles of known chemical content, size, and location is now used for proficiency testing, which is a condition for a forensic laboratory to obtain accreditation in this subject matter. In this publication, the need for optimization of the procedure for the examination of a synthetic specimen, in alignment with the necessary modifications for real gunshot particles, has been addressed. The presented process of validation resulted in two procedures. The first demonstrates the full capacity of the instrument for detecting all particles present in the synthetic specimen, including the 0.5 micrometer particle at the magnification of 250×. The other procedure is the modification of the first, however aiming at 1-micrometer particles or bigger (at the magnification of 120×) and allowing the necessary backscattered signal threshold changes depending on the actual composition of gunshot residue as well as the abundance of light element debris in the case of real gunshot particles.

Irreversible changes in the sea surface temperature threshold for tropical convection to CO2 forcing

Tropical convection plays a critical role in modulating the global climate by influencing climate variability. However, its future projection under climate mitigation scenarios remains uncertain. Here, we found that while the relationship between precipitation intensity and upward motion remains constant regardless of changing CO2 concentrations, the sea surface temperature threshold for tropical convection and the convective zone exhibit hysteretic and irreversible behavior. As the CO2 concentration decreases from its peak (ramp-down), higher tropical ocean temperature leads to higher sea surface temperature thresholds for convection than during the period of increasing CO2 concentration (ramp-up), while convective instability remains the same during both ramp-up and ramp-down. El Niño-like warming during the ramp-down leads to a weakening of the Walker circulation and an expansion of the convective zone in the central to eastern tropical Pacific by a warmer-get-wetter mechanism. Our results suggest that CO2 removal does not guarantee the recovery of tropical convection.

A novel life-cycle analysis framework to assess the performances of tall buildings considering the climate change

Structural performance against wind hazards is necessary in modern tall building design, especially for structures in the region prone to tropical cyclones. In fact, wind-related failures and building life-cycle analysis (LCA) may be impacted by climate change on the increase of frequency and intensity of tropical cyclones. In this study, a novel LCA framework considering the climate change is proposed, which includes taking into account the climate change via the serviceability failure cost for the cases where the building vibrates exceeding the corresponding thresholds. In detail, the non-stationary Poisson process is used to model the occurrence and intensity of tropical cyclones, which in turn leads to the financial loss of the coastal building. Specifically, the vulnerability of the building is derived considering both the uncertainty of the extreme wind speeds in the tropical cyclone boundary layer and the fragility curve which includes the uncertainty from the structural damping ratio. To estimate the maintenance cost, the financial values associated with maintenance-related operations and the emission of greenhouse gas are combined. In order to illustrate the proposed LCA framework, a case study targeting a 240 m high benchmark building located close to the coast of Hong Kong is conducted. In addition, the sensitivity of the damping ratio, limit threshold, and climate change are assessed via the LCA results of the benchmark building.

Threshold Changes in Winter Temperature and Precipitation Drive Threshold Responses Across Nine Global Climate Zones and Associated Biomes

Globally, winter temperatures are rising, and snowpack is shrinking or disappearing entirely. Despite previous research and published literature reviews, it remains unknown whether biomes across the globe will cross important thresholds in winter temperature and precipitation that will lead to significant ecological changes. Here, we combine the widely used Köppen–Geiger climate classification system with worst-case-scenario projected changes in global monthly temperature and precipitation to illustrate how multiple climatic zones across Earth may experience shifting winter conditions by the end of this century. We then examine how these shifts may affect ecosystems within corresponding biomes. Our analysis demonstrates potential widespread losses of extreme cold (&lt;−20°C) in Arctic, boreal, and cool temperate regions. We also show the possible disappearance of freezing temperatures (&lt;0°C) and large decreases in snowfall in warm temperate and dryland areas. We identify important and potentially irreversible ecological changes associated with crossing these winter climate thresholds.

Deep Phenotyping of a Mouse Model for Hearing Instability Disorders.

Hearing instability in Slc26a4 -insufficiency mice may be due to differential expression of genes related to ion homeostasis and activated macrophages. Hearing instability (HI) disorders, defined by either hearing fluctuation or sudden loss, remain incompletely understood. Recent studies have described a Slc26a4 (pendrin)-insufficiency mouse model (DE17.5) that offers a genetically driven model for HI, although deep audiometric and immunohistologic phenotyping of this model remains poorly characterized. Homozygous DE17.5 mice with (F) and without (NF) HI were delineated by serial auditory brainstem responses (ABR) between postnatal days 30 and 60 and compared with adult phenotypically wild-type Slc26a4 -heterozygous controls without evidence of HI (Het). HI was defined as a change in threshold of at least 15 dB in at least two frequencies or at least 20 dB in at least one frequency from the previous week. Stria vascularis (SV) cell type-specific gene expression, endolymphatic hydrops (EH), endocochlear potential (EP), and macrophage activation were analyzed and compared between the cohorts. F mice demonstrated significant reductions in the expression of cell type-specific genes related to ion homeostasis and increased macrophage activation within the SV compared with NF and Het cohorts. Both F and NF DE17.5 homozygous mice demonstrated reductions in EP and increased EH compared with the Het cohort. Deep phenotyping of DE17.5 mice demonstrates changes in EP and EH compared with control; however, the HI phenotype was associated with differential ion homeostasis gene expression and increased macrophage activation in the SV. This provides potential further insights into the underlying pathogenesis and possible immunologic contributions of HI in humans.

Changes in platelet transfusion thresholds utilized in the NICU since PlaNeT-2

Abstract Background Use of prophylactic platelet transfusions in the neonatal setting is a common practice due to concerns about bleeding despite evidence of a developmental mismatch with transfusion of adult platelets. The Platelets for Neonatal Transfusion-Study 2 (PlaNeT-2) published in January 2019 showed that using higher platelet thresholds (50 x 109/L) was associated with more adverse outcomes and no improvement in bleeding events compared to lower platelet thresholds (25 x 109/L). Following this trial, implementation of a lower threshold was provider dependent as there were no changes made to the neonatal intensive care unit (NICU) institutional policies. Our goal was to determine if there were any overall changes in individual clinical practice with thresholds used for platelet transfusions in our NICU and number of transfusions per patient. Methods Our center has a 52 bed level IV NICU that specializes in care for critical and/or preterm infants. We performed a retrospective review from 2017 to 2023 of patients admitted in the NICU who received platelet transfusion and had an available platelet count in the 12 hours prior to the transfusion. Results There were 272 platelet transfusions given to 107 unique NICU patients who had platelet counts available. There were 66 transfusions given to 32 patients pre-PlaNeT-2 (2017-2018) and 206 transfusions given to 75 patients post-PlaNeT-2 (2019-2023). The average platelet count pre-PLaNeT-2(2017 to 2018) was 43 x 109/L (SD±24 x 109/L) and post-PLaNeT-2 (2019 to 2023) was 36 x 109/L (SD±21 x 109/L, p=0.03). Prior to PLaNeT-2, 26% of platelet transfusions were for platelet counts ≤ 25 x 109/L and 35% were for platelet counts between 51 to 100x9/L. Post PLaNeT-2 the percentages changed to 35% and 21% respectively. The percentage of transfusions occurring for platelet counts between 26 to ≤50 x 109/L was 38% and 44%, respectively. The number of platelet transfusions per year did not decrease significantly after the PLaNeT-2 trial (average of 33/year versus 41/year, p=0.5). The number of transfusions per patient before and after PLaNeT-2 did not change (2.1 transfusions per patient versus 2.6 transfusions per patient, p=0.3). Conclusion Platelet thresholds utilized in our center decreased after the PLaNeT-2 trial with less transfusions occurring for platelet counts greater than 50 x 109/L. Although thresholds decreased, the number of transfusions per year and the number of transfusions per patient did not significantly change. Further studies are needed to understand changes in patient outcomes and platelet utilization in the NICU.

Perceptual sensitivity to labeling stereotyped emotion expressions: Associations with age and subclinical psychopathology symptoms from childhood through early adulthood.

This study investigates (a) age-related differences in how the intensity of stereotyped facial expressions influence the emotion label children, adolescents, and adults assign to that face and (b) how this perceptual sensitivity relates to subclinical symptoms of psychopathology. In 2015-2016, 184 participants aged 4-25 years viewed posed stereotypes of angry, fearful, sad, and happy expressions morphed with neutral expressions at 10%-90% intensity. Thin plate regression smoothing splines were used to chart nonlinear associations between age and the perceptual threshold participants needed to assign the emotion label expected based on cultural consensus. Results suggest that sensitivity to labeling stereotypical happy faces as "happy" peaked by age 4. Sensitivity to perceiving stereotypical angry faces as "angry" increased from ages 4 to 7 and then plateaued. In contrast, sensitivity to perceiving stereotypical fearful and sad faces demonstrated protracted development, not reaching a plateau until ages 15 and 16, respectively. Reduction in selecting the "I don't know" response was the primary driver of these age-related changes. Stereotyped fear expressions required the highest intensity to be labeled as such and showed the most marked change in perceptual threshold across development. Interestingly, lower intensity morphs of stereotypical fear faces were frequently labeled "sad." Furthermore, perceiving lower intensity fear morphs was associated with fewer internalizing and externalizing symptoms in participants aged 7-19. This study describes the development of perceptual sensitivity to labeling stereotypical expressions of emotion according to cultural consensus and shows that how people perceive and categorize ambiguous facial expressions is associated with vulnerability to psychopathology. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Assessing the Influence of Zero‐Flow Threshold Choice for Characterising Intermittent Stream Hydrology

ABSTRACTZero‐flow recordings in gauged streamflow data are critically important for intermittent stream research. Acknowledging the high uncertainty in zero‐flow recordings, many studies pick a small number as zero‐flow threshold, below which the flow is considered to be zero. The choice of zero‐flow threshold is often arbitrary or unjustified, which leads us to wonder: would selecting a slightly different threshold change analysis result significantly? Here, we used a simple sensitivity analysis to assess how the choice of zero‐flow threshold impacts the calculated values of relevant metrics to intermittent stream research. Results show that these metrics tended to be more sensitive to lower zero‐flow thresholds, suggesting that even choosing a slightly different threshold could lead to meaningfully different results from the management perspective. This study highlights the need for reasonable justification of the choice of zero‐flow threshold and concludes with potential ways to reduce uncertainty in zero‐flow measurement.

Risk of hearing loss in the opposite ear after tympanomastoidectomy.

The definitive treatment for chronic suppurative otitis media is surgery. Surgical technique and procedure varies according to individual case findings and pathology and may require mastoidectomies in which the canal wall is preserved or lowered to eradicate disease from mastoid air cells. Surgical treatment of chronic middle ear disease carries a risk of damage to the inner ear. The aim of this study was to investigate whether the noise produced by the tour system following chronic ear surgery causes sensorineural hearing loss, a condition for which not many studies have been published in the literature. The study consisted of a total of 49 patients with type I, type II and type III canal wall preservation and 62 patients with tympanoplasty with canal wall preservation and lowering. Bone and air thresholds were compared before and after middle ear surgery. Changes in bone and air thresholds were compared according to the type of tympanoplasty. In the ICW-I, ICW-II and ICW-III tympanoplasties, and in the ICW and CWD tympanoplasties, the preoperative and postoperative values of the opposite ear hearing measurements were performed, and did not differ according to the type of surgery. There is no correlation drilling duration and hearing for the opposite ear. The prevention of postoperative sensorineural hearing loss depends on multiple factors, and assessing the magnitude of hearing loss in relation to these factors is important in determining the success of the surgery.

Characterization of human lightness discrimination thresholds for independent spectral variations.

The lightness of an object is an intrinsic property that depends on its surface reflectance spectrum. The visual system estimates an object's lightness from the light reflected off its surface. However, the reflected light also depends on object extrinsic properties of the scene, such as the light source. For stable perception, the visual system needs to discount the variations due to the object extrinsic properties. We characterize this perceptual stability for variation in two spectral properties of the scene: the reflectance spectra of background objects and the intensity of light sources. We measure human observers' thresholds of discriminating computer-generated images of 3D scenes based on the lightness of a spherical target object in the scene. We measured change in discrimination thresholds as we varied the reflectance spectra of the objects and the intensity of the light sources in the scene, both individually and simultaneously. For small amounts of extrinsic variations, the discrimination thresholds remained nearly constant indicating that the thresholds were dominated by observers' intrinsic representation of lightness. As extrinsic variation increased, it started affecting observers' lightness judgment and the thresholds increased. We estimated that the effects of extrinsic variations were comparable to observers' intrinsic variation in the representation of object lightness. Moreover, for simultaneous variation of these spectral properties, the increase in threshold squared compared to the no-variation condition was a linear sum of the corresponding increase in threshold squared for the individual properties, indicating that the variations from these independent sources combine linearly.

Demographic factors impact the rate of hearing decline across the adult lifespan

BackgroundLittle is known about the natural history of hearing loss in adults, despite it being an important public health problem. The purpose of this study is to describe the rate of hearing change per year over the adult lifespan.MethodsThe 1436 participants are from the MUSC Longitudinal Cohort Study of Age-related Hearing Loss (1988-present). Outcomes are audiometric thresholds at 250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz, averaged across right and left ears, and pure-tone average (PTA). Demographic factors are sex (female/male), race, which is categorized as white or racial Minority, and baseline age group (18-39, 40–59, 60–69, 70+ years). Linear mixed regression models are used to estimate the effect of age (per year) on the rate of threshold and PTA change.ResultsParticipants’ mean age is 63.1 (SD 14.9) years, 57.7% are female, and 17.8% are racial Minority (17.1% were Black or African American). In sex-race-adjusted models, rates of threshold change are 0.42 to 1.44 dB across thresholds. Rates of change differ by sex at most individual thresholds, but not PTA. Females (versus males) showed higher rates of threshold change in higher frequencies but less decline per year in lower frequencies. Black/African American (versus white) participants have lower rates of threshold and PTA change per year. Hearing thresholds decline across the adult lifespan, with older (versus younger) baseline age groups showing higher rates of decline per year.ConclusionsDeclines to hearing occur across the adult lifespan, and the rate of decline varies by sex, race, and baseline age.