Low-frequency Hearing Research Articles

Early synapsids neurosensory diversity revealed by CT and synchrotron scanning.

Non-mammaliaform synapsids (NMS) represent the closest relatives of today's mammals among the early amniotes. Exploring their brain and nervous system is key to understanding how mammals evolved. Here, using CT and Synchrotron scanning, we document for the first time three extreme cases of neurosensory and behavioral adaptations that probe into the wide range of unexpected NMS paleoneurological diversity. First, we describe adaptations to low-frequency hearing and low-light conditions in the non-mammalian cynodont Cistecynodon parvus, supporting adaptations to an obligatory fossorial lifestyle. Second, we describe the uniquely complex and three-dimensional maxillary canal morphology of the biarmosuchian Pachydectes elsi, which suggests that it may have used its cranial bosses for display or low-energy combat. Finally, we introduce a paleopathology found in the skull of Moschognathus whaitsi. Since the specimen was not fully grown, this condition suggests the possibility that this species might have engaged in playful fighting as juveniles-a behavior that is both social and structured. Additionally, this paper discusses other evidence that could indicate that tapinocephalid dinocephalians were social animals, living and interacting closely with one another. Altogether, these examples evidence the wide range of diversity of neurological structures and complex behavior in NMS.

A hidden pathophysiology of endolymphatic hydrops: case report of a patient with spontaneous intracranial hypotension presenting with sudden sensorineural hearing loss with vertigo.

Spontaneous intracranial hypotension (SIH) is characterized by decreased cerebrospinal fluid (CSF) volume due to leakage through the dural membrane. We present the case of a patient with SIH manifested by fluctuating low-frequency hearing loss, tinnitus, and vertigo. In this patient, endolymphatic hydrops in the cochlea and saccule were visualized by means of a special sequence of inner ear magnetic resonance imaging scans, with a gadolinium-based contrast agent administered intravenously. Endolymphatic hydrops is a potential underlying pathophysiology of SIH-associated hearing impairment. We hypothesize that SIH may be a rare cause of endolymphatic hydrops.

The research of the contralateral ear hearing thresholds and the hearing prognosis in unilateral Meniere's disease

Objective:This study analyzed the pure tone audiometry results of the affected ear and the contralateral ear of unilateral Meniere's disease to investigate the correlation of the hearing threshold of the contralateral ear and the hearing prognosis of unilateral Meniere's disease. Methods:In this study, the follow-up data of 135 patients with unilateral Meniere's disease in Beijing Tongren Hospital were used to analyze the pure tone audiometry results of the affected and contralateral ears at the first visit and 1 year later. Results:①At the first visit, there was no statistically significant difference between the mean hearing thresholds of the affected ear in the normal hearing group and the high-frequency hearing loss group of the contralateral ear（P>0.05）. ②The range of improvement of hearing thresholds in the affected ear was greater in the contralateral ear normal hearing group than in the contralateral ear high-frequency hearing loss group. In the normal hearing group of the contralateral ear, the hearing thresholds of the affected ear at 0.25 kHz（P<0.01）, 0.50 kHz（P<0.01）, 1.00 kHz（P<0.01）, and 2.00 kHz（P<0.05） were significantly improved; and in the high-frequency hearing loss group of the contralateral ear, the hearing thresholds at 0.25 kHz（P<0.01） hearing thresholds improved significantly, and there was no significant difference between the rest of the frequencies before and after treatment（P>0.05）. A consistent pattern was observed in both higher and lower age groups. ③After 1 year of follow-up, the low and mid-frequency hearing of the affected ear improved. 0.25 kHz（P<0.01）, 0.50 kHz（P<0.01）, 1.00 kHz（P<0.01） hearing thresholds improved significantly; 8.00 kHz hearing thresholds decreased slightly（P<0.05）. Conclusion:After standardized treatment, the results of 1-year follow-up suggested that the low-frequency hearing of MD patients could be improved, but the high-frequency hearing was slightly decreased. The hearing prognosis of the affected ear with normal hearing threshold of the contralateral ear may be better.

Posterior Semicircular Canal Dehiscence with Vestibulo-Ocular Reflex Reduction for the Affected Canal at the Video-Head Impulse Test: Considerations to Pathomechanisms.

Posterior semicircular canal dehiscence (PSCD) has been demonstrated to result in a third mobile window mechanism (TMWM) in the inner ear similar to superior semicircular canal dehiscence (SSCD). Typical clinical and instrumental features of TMWM, including low-frequency conductive hearing loss (CHL), autophony, pulsatile tinnitus, sound/pressure-induced vertigo and enhanced vestibular-evoked myogenic potentials, have been widely described in cases with PSCD. Nevertheless, video-head impulse test (vHIT) results have been poorly investigated. Here, we present six patients with PSCD presenting with a clinical scenario consistent with a TMWM and an impaired vestibulo-ocular reflex (VOR) for the affected canal on vHIT. In two cases, an additional dehiscence between the facial nerve and the horizontal semicircular canal (HSC) was detected, leading to a concurrent VOR impairment for the HSC. While in SSCD, a VOR gain reduction could be ascribed to a spontaneous "auto-plugging" process due to a dural prolapse into the canal, the same pathomechanism is difficult to conceive in PSCD due to a different anatomical position, making a dural herniation less likely. Alternative putative pathomechanisms are discussed, including an endolymphatic flow dissipation during head impulses as already hypothesized in SSCD. The association of symptoms/signs consistent with TMWM and a reduced VOR gain for the posterior canal might address the diagnosis toward PSCD.

Successful hearing preservation and improved subjective sound quality with the flexible 28-mm electrode array

IntroductionFlexible electrode arrays have shown to be an effective solution to ensure atraumatic insertion. However, flexible full-length electrodes are not suited for patients with smaller cochleae. Therefore, this study aimed to evaluate short-term and medium-term hearing preservation (HP) in patients with low-frequency residual hearing (LFRH) who were implanted with a flexible 28-mm electrode array and who did not meet the indication criteria for electric-acoustic stimulation (EAS).MethodsHP was determined based on the pure-tone audiogram of the implanted ear. A bisyllable sentence test was used to assess speech perception in quiet and in noise. The hearing implant sound quality index (HISQUI19) evaluated self-reported hearing quality. The tests were conducted pre- and post-operatively, at first fitting, and at 1, 3, 6, and 12 months after first fitting.ResultsAt 12 months post first fitting, 2 patients had complete HP; 4 patients had partial HP. Speech perception scores improved in all patients of the study. The mean scores on the bisyllable sentence test in noise significantly increased from 30% pre-operatively to 62% 6 months post first-fitting and to 68% 12 months post first-fitting. The mean score of the HISQUI19 improved from 40.56 (poor) pre-operatively to 72.56 (moderate) 1 month post first-fitting and to 90.29 (good) 12 months post first-fitting.ConclusionThe 28-mm flexible electrode array facilitates atraumatic surgery and HP and results in improved speech perception and subjective sound quality scores.

Spatial release from masking with simulated hybrid cochlear implant speech

Spatial release from masking (SRM) is the improvement in speech intelligibility when the masking signals are spatially separated from the target signal. Cochlear implant (CI) users utilizing electric-only (E-Only) stimulation had poorer speech recognition than CI users utilizing electric-acoustic stimulation (EAS). Previous research investigating SRM on hybrid CI users big spatial separations (±90°) between the target and the maskers which were unrealistic in conversational settings. Here, we present SRM data using natural speech, simulated CI speech, and simulated EAS speech from young, normal hearing listeners for smaller, yet realistic, spatial separations between the target and the maskers. An eight-channel noise-excited vocoder was used to simulate cochlear implant processing and low-frequency filtering was used to simulate residual low-frequency hearing. Five spatial configurations were used: (colocated (target and the two maskers presented from 0° azimuth) and one of four spatially separated conditions (target at 0°, symmetrical maskers at ± 5°, ± 10°, ±15°, or ±30°). Initial analysis of the data revealed that the listeners had significantly poorer speech identification thresholds for the simulated CI speech when compared to EAS speech. The individual variability and the relationship between the speech identification thresholds in the three conditions will be discussed.

Association between blood volatile organic aromatic compound concentrations and hearing loss in US adults.

Benzene, ethylbenzene, meta/para-xylene, and ortho-xylene, collectively referred to as benzene, ethylbenzene, and xylene (BEX), constitute the main components of volatile organic aromatic compounds (VOACs) and can have adverse effects on human health. The relationship between exposure to BEX and hearing loss (HL) in the adult U.S. population was aimed to be assessed. Cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) for the years 2003-2004, 2011-2012, and 2015-2016 were analyzed. This dataset included complete demographic characteristics, pure-tone audiometry measurements, and volatile organic compound detection data from the NHANES database. A weighted multivariate logistic regression model was employed to investigate the associations between blood BEX concentrations HL, low-frequency hearing loss (SFHL), and high-frequency hearing loss (HFHL). 2174 participants were included, with weighted prevalence rates of HL, SFHL, and HFHL being 46.81%, 25.23%, and 45.86%, respectively. Exposure to benzene, ethylbenzene, meta/para-xylene, and ortho-xylene, and cumulative BEX concentrations increased the risk of hearing loss (odds ratios [ORs] were 1.36, 1.22, 1.42, 1.23, and 1.31, respectively; all P < 0.05). In the analysis with SFHL as the outcome, ethylbenzene, m-/p-xylene, o-xylene, benzene, and overall BEX increased the risk (OR 1.26, 1.21, 1.28, 1.20, and 1.25, respectively; all P < 0.05). For HFHL, exposure to ethylbenzene, m-/p-xylene, o-xylene, benzene, and overall BEX increased the risk (OR 1.36, 1.22, 1.42, 1.22, and 1.31, respectively; all P < 0.05). Our study indicated that a positive correlation between individual or cumulative exposure to benzene, ethylbenzene, meta/para-xylene, and ortho-xylene and the risk of HL, SFHL, and HFHL. Further research is imperative to acquire a more comprehensive understanding of the mechanisms by which organic compounds, notably BEX, in causing hearing loss and to validate these findings in longitudinal environmental studies.

Functional Hearing Preservation in Cochlear Implantation: The Miami Cocktail Effect.

To investigate if pharmacological treatment with prednisone and L-N-acetylcysteine (STE + NAC) influence functional hearing preservation in cochlear implant (CI) surgery. Preimplantation and postimplantation longitudinal case-control study. Tertiary referral center. Pediatric and adult recipients of CI with preimplantation functional hearing defined as an average of air-conducted thresholds at 125, 250, and 500 Hz (low-frequency pure-tone average [LFPTA]) <80 dB. Preimplantation and postimplantation audiometry. Weight-adjusted oral prednisone and L-N-acetylcysteine starting 2 days before surgery (Miami cocktail). Prednisone was continued for 3 days and L-N-acetylcysteine for 12 days after surgery, respectively. Cochlear implantation with conventional length electrodes. Proportion of patients with LFPTA <80 dB, and LFPTA change at 1-year postimplantation. All 61 patients received intratympanic and intravenous dexamethasone intraoperatively, with 41 patients receiving STE + NAC and 20 patients not receiving STE + NAC. At 1-year postimplantation, the proportion of functional hearing preservation was 83% in the STE + NAC group compared with 55% of subjects who did not receive STE + NAC ( p = 0.0302). The median LFPTA change for STE + NAC-treated and not treated subjects was 8.33 dB (mean, 13.82 ± 17.4 dB) and 18.34 dB (mean, 26.5 ± 23.4 dB), respectively ( p = 0.0401, Wilcoxon rank test). Perioperative STE + NAC treatment resulted in 10 dB of LFPTA better hearing than when not receiving this treatment. Better low-frequency preimplantation hearing thresholds were predictive of postimplantation functional hearing. No serious side effects were reported. Perioperative STE + NAC, "The Miami Cocktail," was safe and superior to intraoperative steroids alone in functional hearing preservation 1-year after cochlear implantation.

Correlation of endolymphatic hydrops and perilymphatic enhancement with the clinical features of Ménière's disease.

To use three-dimensional real inversion recovery (3D-real IR) MRI to investigate correlations between endolymphatic hydrops (EH) grades or the degree of perilymphatic enhancement (PE) and clinical features of Ménière's disease (MD), as previous findings have been inconsistent. A total of 273 consecutive patients with definite unilateral MD were retrospectively enrolled from September 2020 to October 2021. All patients underwent 3D-real IR and 3D-T2WI 6 h after intravenous gadolinium injection. MD-related symptom duration and vertigo frequency were recorded. EH grades were evaluated, the signal intensity ratio (SIR) was measured, and correlations between clinical features and EH, PE were assessed respectively. The study included 123 males and 150 females, with a mean age of 53.0 years. A longer duration of vertigo was associated with higher cochlear EH grades, whereas the opposite was true for the duration of aural fullness. A longer time since vertigo onset was associated with higher vestibular EH grades; the opposite was true for the duration of individual vertigo attacks. The multiple regression analysis revealed that age, tinnitus duration, and vestibular EH were risk factors for SIR. Furthermore, the low-frequency hearing threshold (HT) was a risk factor for cochlear and vestibular EH, and the SIR. The EH grade and SIR (an indicator for the quantitative evaluation of PE) were correlated with clinical features and HT of MD; thus, imaging can be a valuable tool in planning individualised treatment. This study revealed that the grade of endolymphatic hydrops and degree of perilymphatic enhancement positively correlates with the length of time since onset of clinical symptoms and hearing thresholds in patients with Ménière's disease, facilitating the tailored treatment. • Relationships between 3-dimensional real inversion recovery features and clinical symptoms in Ménière's disease are unknown. • Symptom duration and hearing thresholds correlated with endolymphatic hydrops grades and degree of perilymphatic enhancement. • MRI features correlate with MD severity; thus, imaging is valuable for planning tailored treatment.

Insertion Results and Hearing Outcomes of a Slim Lateral Wall Electrode.

The clinical outcomes of cochlear implantation vary for several reasons. It is necessary to study the different electrodes and variables for further development. The aim of this study is to report the clinical outcomes of a new slim lateral wall electrode (SlimJ). Data of 25 cochlear implantations in 23 patients with the SlimJ electrode were retrospectively collected. The insertion results were assessed by image fusion of the preoperative computed tomography (CT), magnetic resonance imaging (MRI), and postoperative cone-beam CT. The hearing outcomes were evaluated by the improvement of speech recognition in noise, measured preoperatively and at follow-up. Postoperative pure-tone thresholds were obtained in cases with preoperative functional low frequency hearing [PTA (0.125-0.5 kHz) ≤ 80 dB HL]. The preoperative mean speech reception threshold (SRT) was +0.6 dB signal-to-noise ratio (SNR) (SD ± 4.2 dB) and the postoperative -3.5 dB SNR (SD ± 2.3 dB). The improvements between the preoperative and postoperative SRT levels ranged from 0.0 to 15.1 dB, with a mean improvement of 4.2 dB (SD ± 3.6 dB). Residual hearing in low frequencies (mean PTA(125-500 Hz)) was preserved within 30 dB HL in 70% and within 15 dB HL in 40% of patients who had preoperatively functional low frequency hearing. Mean insertion depth angle (IDA) was 401° (SD ± 41°). We observed scalar translocations from scala tympani to scala vestibuli in 2 ears (9%). The relatively atraumatic insertion characteristics make the SlimJ array feasible for hearing preservation cochlear implantation. The hearing outcomes are comparable to those reported for other electrodes and devices.

Auditory Neuropathy Spectrum Disorder in Individuals with Sickle Cell Anemia: Case Study.

The present study attempted to understand the association between Auditory neuropathy spectrum disorder (ANSD) and Sickle cell anemia (SCA) and to recognize possible causative factors for the presence of ANSD in SCA individuals. Two cases, 24 years male and 17years female with a laboratory-confirmed diagnosis of Sickle cell anemia underwent detailed audiological evaluation i.e., pure tone audiometry, speech audiometry, immittance audiometry, otoacoustic emission, and auditory brainstem responses. Audiological evaluation revealed a bilateral moderate low-frequency sensorineural hearing loss in male and bilateral moderately severe sensorineural Hearing loss in female case with elevated Speech Recognition Threshold and poor Speech Identification Scores. 'A' type tympanogram with the absence of Acoustic reflexes and the presence of Otoacoustic emission with no distinct and reproducible peak V in Auditory Brainstem Response (ABR) at 90 dBnHL with the presence of ringing cochlear microphonics on polarity reversal collectively indicating bilateral ANSD in both cases. ANSD and SCA are reported to have a genetic basis of etiology. There might be possibilities that one genetic condition may be common in manifesting both conditions or one genetic condition can cause the presence of another genetic condition or can exaggerate the evolution of another genetic condition. Also, abnormal ABR findings indicate the possibility of neuropathological involvement in isolation or in combination with genetic abnormalities that need detailed investigation to understand non-genetic causative factors. Thus, paved the path for further research in this line and might provide better rehabilitative options.

GelMA/PEDOT:PSS Composite Conductive Hydrogel-Based Generation and Protection of Cochlear Hair Cells through Multiple Signaling Pathways.

Recent advances in cochlear implantology are exemplified by novel functional strategies such as bimodal electroacoustic stimulation, in which the patient has intact low-frequency hearing and profound high-frequency hearing pre-operatively. Therefore, the synergistic restoration of dysfunctional cochlear hair cells and the protection of hair cells from ototoxic insults have become a persistent target pursued for this hybrid system. In this study, we developed a composite GelMA/PEDOT:PSS conductive hydrogel that is suitable as a coating for the cochlear implant electrode for the potential local delivery of otoregenerative and otoprotective drugs. Various material characterization methods (e.g., 1H NMR spectroscopy, FT-IR, EIS, and SEM), experimental models (e.g., murine cochlear organoid and aminoglycoside-induced ototoxic HEI-OC1 cellular model), and biological analyses (e.g., confocal laser scanning microscopy, real time qPCR, flow cytometry, and bioinformatic sequencing) were used. The results demonstrated decent material properties of the hydrogel, such as mechanical (e.g., high tensile stress and Young's modulus), electrochemical (e.g., low impedance and high conductivity), biocompatibility (e.g., satisfactory cochlear cell interaction and free of systemic toxicity), and biosafety (e.g., minimal hemolysis and cell death) features. In addition, the CDR medicinal cocktail sustainably released by the hydrogel not only promoted the expansion of the cochlear stem cells but also boosted the trans-differentiation from cochlear supporting cells into hair cells. Furthermore, hydrogel-based drug delivery protected the hair cells from oxidative stress and various forms of programmed cell death (e.g., apoptosis and ferroptosis). Finally, using large-scale sequencing, we enriched a complex network of signaling pathways that are potentially downstream to various metabolic processes and abundant metabolites. In conclusion, we present a conductive hydrogel-based local delivery of bifunctional drug cocktails, thereby serving as a potential solution to intracochlear therapy of bimodal auditory rehabilitation and diseases beyond.

Perception of voice cues in school-age children with hearing aids.

The just-noticeable differences (JNDs) of the voice cues of voice pitch (F0) and vocal-tract length (VTL) were measured in school-aged children with bilateral hearing aids and children and adults with normal hearing. The JNDs were larger for hearing-aided than normal-hearing children up to the age of 12 for F0 and into adulthood for all ages for VTL. Age was a significant factor for both groups for F0 JNDs, but only for the hearing-aided group for VTL JNDs. Age of maturation was later for F0 than VTL. Individual JNDs of the two groups largely overlapped for F0, but little for VTL. Hearing thresholds (unaided or aided, 500-400 Hz, overlapping with mid-range speech frequencies) did not correlate with the JNDs. However, extended low-frequency hearing thresholds (unaided, 125-250 Hz, overlapping with voice F0 ranges) correlated with the F0 JNDs. Hence, age and hearing status differentially interact with F0 and VTL perception, and VTL perception seems challenging for hearing-aided children. On the other hand, even children with profound hearing loss could do the task, indicating a hearing aid benefit for voice perception. Given the significant age effect and that for F0 the hearing-aided children seem to be catching up with age-typical development, voice cue perception may continue developing in hearing-aided children.

Association of serum 25-hydroxyvitamins D2 and D3 with hearing loss in US adults: analysis from National Health and Nutrition Examination Survey, 2015-2016.

Hearing loss (HL) is increasingly recognized as a significant global public health issue, and research on its relationship with vitamin D levels has gained wider attention. However, the association between serum biomarkers 25-hydroxyvitamin D2 (25(OH)D2) and D3 (25(OH)D3) with different types of HL remains unclear. This study aimed to investigate the potential association of serum 25(OH)D2 and 25(OH)D3 with HL in US adults. A sample of 3,684 individuals aged 20-69 years from the 2015-2016 National Health and Nutrition Examination (NHANES) was analyzed in this study. HL was defined as a pure tone average > 25 dB in either ear at low frequencies (500, 1,000, 2000 Hz), speech frequencies (500, 1,000, 2000, 4,000 Hz), and high frequencies (3,000, 4,000, 6,000, 8,000 Hz). Logistic regression was employed to examine the association between serum 25(OH)D2 and 25(OH)D3 and HL. The study population was then stratified by age, gender, race, and education level to analyze potential differences between adults in different subgroups. In the multivariate analysis, it was found that serum 25(OH)D2 was independently associated with low-frequency hearing loss (LFHL) (OR: 1.012 [95% CI, 1.005-1.020]) and speech-frequency hearing loss (SFHL) (OR: 1.011 [95% CI, 1.003-1.018]). Restrictive cubic spline analysis demonstrated a linear dose-response relationship between serum 25(OH)D2 levels and LFHL (p for linearity <0.001), as well as SFHL (p for linearity = 0.001). Conversely, an L-shaped association was observed between serum 25(OH)D3 levels and both LFHL (p for nonlinearity = 0.014) and SFHL (p for nonlinearity = 0.025), with threshold values identified at 35.3 and 36.5 nmol/L, respectively. Higher levels of serum 25(OH)D3 were associated with a lower probability of high-frequency hearing loss (HFHL) (OR: 0.994 [95% CI, 0.989-0.999]), with a threshold value identified at 53.9 nmol/L. Furthermore, a significant interaction between diabetes and serum 25(OH)D2 in LFHL was revealed through subgroup analysis (p = 0.041). In the non-diabetic population, serum 25(OH)D2 maintained its association with LFHL. Our findings suggested a positive association between serum 25(OH)D2 concentrations and both LFHL and SFHL in the studied cohort. Additionally, an L-shaped relationship was found between serum 25(OH)D3 and LFHL and SFHL, and higher levels of serum 25(OH)D3 were identified to be associated with a lower risk of HFHL.

Electric boat underwater radiated noise and its potential impact on species of conservation interest

Electric boats are thought to be noiseless, but in-situ measurements are generally rare. The Underwater Radiated Noise (URN) of 8-m Trimaran Pontoon Boat with two outboard electric engines was measured in the Miramare Marine Protected Area (Trieste, Italy), together with the URN of a fibreglass 5-m boat, with a outboard gasoline engine, for comparisons. International standards and guidelines for shallow waters were considered. URN were provided in one-third octave band and in narrow band spectra. The electric boat produced a low input of underwater noise at low frequencies. Given a low-frequency hearing sensitivity, the listening space reduction (LSR) was lower when generated by the electric than by combustion engine boat for the brown meagre, a local Teleost fish. No difference was found for the bottlenose dolphin LSR although continuous, tonal, high frequency components generated by the electric boat are expected to be highly detrimental for the bottlenose dolphin.

The association between electrode impedance and short-term outcomes in cochlear implant recipients of slim modiolar and slim straight electrode arrays

Objectives Electrode impedance measurements from cochlear implants (CI) reflect the status of the electrode array as well as the surrounding cochlear environment, and could provide a clinical index of functional changes with the CI. The goals of this study were to examine (1) the impact of electrode array type on electrode impedance, and (2) the relationship between electrode impedance and short-term hearing preservation and speech recognition outcomes. Methods Retrospective study of 115 adult hearing preservation CI recipients of a slim modiolar or slim straight array. Common ground electrode impedances, pre- and post-operative hearing thresholds and CNC word recognition scores were retrieved. Results Electrode impedances were significantly higher for recipients of the straight electrode array. Within individuals, electrode impedances were stable after the first week post-activation. However, increased standard deviation of electrode impedances was associated with greater loss of low frequency hearing at initial activation, and with poorer speech recognition at 6 months post-implantation. Conclusions Results demonstrate that electrode impedances depend on the type of implanted array. Findings also suggest that there may be a role for the variability in electrode impedance across electrodes as an indicator of changes in the intracochlear environment that contribute to outcomes with a CI.

Short-term observation of electrical acoustic stimulation in patients with low frequency residual hearing after cochlear implant

Objective: To analyze the effects of electrical acoustic stimulation (EAS) on speech and tone recognition as well as music perception in children with low-frequency residual hearing (LFRH) after cochlear implant (CI). Methods: A total of twelve Mandarin patients with LFRH who underwent unilateral CI from January 2017 to October 2020 were recruited, including 8 males and 4 females. There were 5 cases of pre-lingual deafness and 7 cases of post-lingual deafness. The median age at implantation was 12 years old (3-62 years). All patients had residual hearing (RH) before surgery, wore hearing aid (HA) timely, had an effective rehabilitation and the duration of use of electrical stimulation was 37.0±16.2 months. On the implanted side, the thresholds of 125 Hz and 250 Hz were less than and equal to 80 dB HL after implantation. A two-month follow-up clinical study was conducted with the EAS devices. The EAS effects were evaluated before, immediately after and 2 months after upgrade, including speech recognition rate, tone recognition and music tests. SPSS 23.0 software was used for statistical analysis. Results: A total of ten patients completed a two-month clinical follow-up and efficiency evaluation. Compared to the electrical stimulation, the recognition rate of spondee word significantly decreased after the immediate use of EAS (71.7±4.3 vs 79.6±3.1, P=0.018). Compared to the electrical stimulation as well as immediate use of EAS, the results of sentence in noise, tone in noise, and SRT of sentence in noise were all significantly improved at 2 months after use of EAS (P<0.05). The pitch discrimination was significantly improved at 2 months after the use of EAS compared with that before the use of EAS (P=0.042). Compared with before (P=0.021) and immediately (P=0.017) use of EAS, the ability of rhythm resolution was significantly improved. There were no significant differences in other test results (P>0.05). Conclusions: The low-frequency acoustic information provided by EAS as well as the electrical-acoustic stimulation mode can provide rich auditory cues of speech perception in noise, tone recognition in noise, and musical discrimination for CI subjects. It can promote the improvement of complex listening ability of CI patients undergoing long-term electrical stimulation in a short time and comprehensively improve their hearing capacities.

Blood biomarkers and lifestyle factors in dementia prevention

AbstractBackgroundAlzheimer’s disease (AD) is a neurodegenerative disorder with preclinical period that may begin more than 15‐20 years before onset without any clinical symptoms. Risk factors for intervention include obesity in middle age, lack of exercise, hypertension in middle age, diabetes mellitus, smoking, and hearing loss in middle age. Our research indicated that plasma proteins, such as apoA1, transthyretin, and complement C3, may serve as potential biomarkers for mild cognitive impairment (MCI) and Alzheimer’s disease. In this study, we analyzed the associations between risk and protective factors and these plasma protein levels to establish a risk assessment method for dementia.MethodIn present study, we measured blood biomarkers, including apoA1, transthyretin, and complement C3, in 1,736 subjects. We collected medical data from annual health examinations and clinical records of the participants. Additionally, lifestyle questionnaires were incorporated into the research.ResultOur analyses revealed that the risk values in the composite score indicated by the three blood biomarkers were higher in those with a history of dementia and diabetes than in those without a history of dementia and diabetes. The odds ratios (OR) for MCI were 5.27 (CI: 2.14‐13.2) and 1.59 (CI: 1.04‐2.45), respectively. Smoking exhibited a high‐risk value (OR: 1.87, CI: 1.15‐3.01), while smoking cessation led to higher apoA1 levels than in those who continued to smoke. Utilizing the composite score as an index, we analyzed factors that increase or decrease the composite score based on the receipt diagnosis history, health checkup data, and lifestyle questionnaires. We found that the high‐risk group in the composite score was associated with low HDL cholesterol (OR 0.94), high HbA1c (OR 1.6), and right high frequency hearing loss (OR 2.97). Furthermore, we identified several protective factors against MCI, including regular walking and strong physical exercise, drinking 100% fruit and vegetable juices, and avoiding sweetened beverages, and eating sashimi and miso soup.ConclusionOur findings suggest that a firm commitment to lifestyle‐related disease treatment and high‐impact exercise from middle age can help prevent dementia. Additionally, the blood test we used may be useful in presenting specific methods of dementia prevention and evaluating their effectiveness.

Three Blind Moles: Molecular Evolutionary Insights on the Tempo and Mode of Convergent Eye Degeneration in Notoryctes typhlops (Southern Marsupial Mole) and Two Chrysochlorids (Golden Moles).

Golden moles (Chrysochloridae) and marsupial moles (Notoryctidae) are textbook examples of convergent evolution. Both taxa are highly adapted to subterranean lifestyles and have powerful limbs for digging through the soil/sand, ears that are adapted for low-frequency hearing, vestigial eyes that are covered by skin and fur, and the absence of optic nerve connections between the eyes and the brain. The eyes of marsupial moles also lack a lens as well as retinal rods and cones. Two hypotheses have been proposed to account for the greater degeneracy of the eyes of marsupial moles than golden moles. First, marsupial moles may have had more time to adapt to their underground habitat than other moles. Second, the eyes of marsupial moles may have been rapidly and recently vestigialized to (1) reduce the injurious effects of sand getting into the eyes and (2) accommodate the enlargement of lacrimal glands that keep the nasal cavity moist and prevent the entry of sand into the nasal passages during burrowing. Here, we employ molecular evolutionary methods on DNA sequences for 38 eye genes, most of which are eye-specific, to investigate the timing of relaxed selection (=neutral evolution) for different groups of eye-specific genes that serve as proxies for distinct functional components of the eye (rod phototransduction, cone phototransduction, lens/cornea). Our taxon sampling included 12 afrothere species, of which two are golden moles (Amblysomus hottentotus, Chrysochloris asiatica), and 28 marsupial species including two individuals of the southern marsupial mole (Notoryctes typhlops). Most of the sequences were mined from databases, but we also provide new genome data for A. hottentotus and one of the two N. typhlops individuals. Even though the eyes of golden moles are less degenerate than the eyes of marsupial moles, there are more inactivating mutations (e.g., frameshift indels, premature stop codons) in their cone phototransduction and lens/cornea genes than in orthologous genes of the marsupial mole. We estimate that cone phototransduction recovery genes were inactivated first in each group, followed by lens/cornea genes and then cone phototransduction activation genes. All three groups of genes were inactivated earlier in golden moles than in marsupial moles. For the latter, we estimate that lens/cornea genes were inactivated ~17.8 million years ago (MYA) when stem notoryctids were burrowing in the soft soils of Australian rainforests. Selection on phototransduction activation genes was relaxed much later (5.38 MYA), during the early stages of Australia's aridification that produced coastal sand plains and eventually sand dunes. Unlike cone phototransduction activation genes, rod phototransduction activation genes are intact in both golden moles and one of the two individuals of N. typhlops. A second marsupial mole individual has just a single inactivating mutation in one of the rod phototransduction activation genes (PDE6B). One explanation for this result is that some rod phototransduction activation genes are pleiotropic and are expressed in extraocular tissues, possibly in conjunction with sperm thermotaxis.

Development and Application of a Reference-Interval Approach to Tympanometric Norms Using U.S. Population Data for Ages 6-80+ Years.

United States national data for tympanometric measures from 16,614 ears included in the National Health and Nutrition Examination Survey for 2015-2016 and 2017-2020 were analyzed and described. Analyses were primarily descriptive and relied on distribution-free medians and cumulative distribution functions (CDFs). Differences between CDFs were examined using Cohen's h effect size. Results are presented for the age range 6-80+ years. A reference interval (RI) approach was pursued in which the interval from the 2.5th to the 95th percentile for healthy ears was specified for peak-compensated static admittance (Ytm+), tympanometric peak pressure, tympanometric width, and equivalent acoustic ear-canal volume (Vea+). Separate RIs were required for 6- to 13-year-olds compared to those 14-80+ years of age for all four tympanometric measures. For both age groups, a separate RI was warranted for each sex for Ytm+ and Vea+. For those 14-80+ years of age, a separate RI was also needed for non-Hispanic Asians for Ytm+. When these RIs were applied to the full data set, about 5%-10% of ears were found to be either below the lower limit or above the upper limit of the RI. Those ears outside the RI limits had about 5 dB higher low-frequency hearing thresholds than those within RI limits. Both Ytm+ and Vea+ were found to depend on body size. RIs for tympanometric measures from individuals with healthy ears were established, and when applied to the general U.S. population 6-80+ years of age, 5%-10% of ears fell outside the RIs depending on the measure.