Frequency Hearing Research Articles

Temporary Hearing Threshold Shift and Testing the Equal-Energy Hypothesis in Harbor Seals (Phoca vitulina) After Exposure to a One-Sixth-Octave Noise Band Centered at 8 kHz

Susceptibility to temporary hearing threshold shift (TTS) in harbor seals (Phoca vitulina) depends, in part, on the frequency of the fatiguing sound (the sound causing the shift). The TTS induced and the pattern of hearing recovery were documented in two female harbor seals after exposure for one hour to a continuous, constant-amplitude one-sixth-octave noise band (NB) at 8 kHz. This fatiguing sound was emitted at average received sound pressure levels (SPLs) estimated at between 138 and 156 dB re 1 µPa, resulting in sound exposure levels (SELs) of 174 to 192 dB re 1 µPa2s. Hearing thresholds for narrow-band sweeps were determined at 8, 11.3, and 16 kHz. The hearing frequency most affected was 11.3 kHz, half an octave above the fatiguing sound’s center frequency. Higher SELs were more likely to result in TTS than lower SELs. At hearing frequencies 8 and 16 kHz, initial TTS (1 to 4 min after the sound stopped) only occurred after exposure to the highest SEL (192 dB re 1 µPa2s). Recovery of hearing took longer after large TTSs than after small TTSs. The equal-energy hypothesis was tested by exposing the seals to the same continuous fatiguing sound with SPLs between 149 and 165 dB re 1 µPa, and exposure durations between two and 80 min; all seven combinations had the same SEL of 186 dB re 1 µPa2s. The equal-energy hypothesis was supported in both seals for the frequency, SPL, and duration ranges that were tested; thus, SEL can be used to predict the TTS elicited in harbor seals by continuous, constant-amplitude sound around 8 kHz. The TTS-onset SEL for the NB at 8 kHz, taken together with the TTS-onset SELs for fatiguing sound frequencies tested in previous studies, can form the basis for a revised TTS-onset function for harbor seals.

Temporary Hearing Threshold Shift in California Sea Lions (Zalophus californianus) Due to a Noise Band Centered at 40 kHz and Comparison with Shifts Due to Lower-Frequency Sounds

California sea lions (Zalophus californianus) exposed to anthropogenic noise may experience temporary hearing threshold shift (TTS). The function used in regulations to protect their hearing from such damage in the Pacific Ocean is based on only one datapoint, so more data are needed. To determine their frequency-dependent susceptibility to noise-induced TTS, two California sea lions were exposed for 60 minutes to a continuous one-sixth-octave noise band (NB) centered at 40 kHz as the fatiguing sound, at sound pressure levels of 119 to 143 dB re 1 µPa, resulting in sound exposure levels (SELs) of 155 to 179 dB re 1 µPa2s. TTSs were quantified at the center frequency of the fatiguing sound and up to one octave above that frequency (at 40, 50, 56.5, 63, and 80 kHz). Statistically significant TTS occurred at all hearing test frequencies; higher SELs caused greater TTSs. Significant onset of TTS(1-4 min) occurred after exposure to a minimum SEL of 167 dB re 1 µPa2s—a shift of 5.2 dB at hearing frequency 56.5 kHz. At other hearing frequencies, onset of TTS1-4 occurred at SEL 173 dB re 1 µPa2s. TTSs1-4 ≤ 8 dB recovered within 12 min, and TTSs1-4 of > 8 dB recovered within 60 min. TTSs and hearing recovery patterns were similar in both subjects. Comparison with TTS data for the species’ hearing frequency range (0.6 to 40 kHz) shows that after exposure to fatiguing sound frequencies of 0.6, 1, 4, 8, and 16 kHz, the largest TTS1-4 occurred half an octave above the frequency of each of the fatiguing sounds. After exposure to fatiguing sound frequencies 2, 32, and 40 kHz, the largest TTS occurred at the frequency of the fatiguing sounds. Recovery patterns after exposure to the NB at 40 kHz were similar to those after exposure to NBs at 0.6, 1, 2, 4, 8, 16, and 32 kHz. Over almost the entire hearing range, the shape of the audiogram is a poor predictor of the shape of the TTS-onset function. The low TTS-onset SELs show that the hearing of California sea lions is more vulnerable to injury by anthropogenic sound in the oceans than was previously thought.

Minimally disruptive auditory cues: their impact on visual performance in virtual reality

AbstractVirtual reality (VR) has the potential to become a revolutionary technology with a significant impact on our daily lives. The immersive experience provided by VR equipment, where the user’s body and senses are used to interact with the surrounding content, accompanied by the feeling of presence elicits a realistic behavioral response. In this work, we leverage the full control of audiovisual cues provided by VR to study an audiovisual suppression effect (ASE) where auditory stimuli degrade visual performance. In particular, we explore if barely audible sounds (in the range of the limits of hearing frequencies) generated following a specific spatiotemporal setup can still trigger the ASE while participants are experiencing high cognitive loads. A first study is carried out to find out how sound volume and frequency can impact this suppression effect, while the second study includes higher cognitive load scenarios closer to real applications. Our results show that the ASE is robust to variations in frequency, volume and cognitive load, achieving a reduction of visual perception with the proposed hardly audible sounds. Using such auditory cues means that this effect could be used in real applications, from entertaining to VR techniques like redirected walking.

Low Bone Mineral Density Is Associated with High-Frequency Hearing Impairment in Women Over 50: An Observational Study in Korea.

Osteoporosis and hearing impairment are known to be associated, but specific data regarding gender, bone mineral density (BMD) measurement sites, and hearing frequency ranges remain unclear. This study aimed to clarify the relationship between hearing loss and BMD in adults over the age of 50. Additionally, the study sought to determine the frequency ranges of pure tone audiometry (PTA) related to osteoporosis, identify BMD measurement sites, and investigate gender differences. A total of 1,523 adults (651 men and 872 women) over the age of 50, who participated in a medical health check-up at a university hospital, were included. PTA was conducted to assess hearing, and BMD was measured using dual-energy X-ray absorptiometry at the lumbar vertebrae (LV) and femur. In women over the age of 50, a significant association was observed between hearing impairment and osteoporosis (P<0.01), but no such association was found in men. Lumbar BMD (L1-4) in women was significantly associated with hearing loss at 4,000 and 8,000 Hz (both P<0.05), whereas femoral neck and total femur BMD showed no significant relationship. In multiple logistic regression analysis, the odds ratio (OR) between osteoporosis and hearing threshold at 4,000 Hz (OR, 2.078; 95% confidence interval [CI], 1.092-3.954) and 8,000 Hz (OR, 2.648; 95% CI, 1.543-4.544) remained statistically significant in women after adjusting for age and other risk factors. In women over the age of 50, low BMD at the LV is significantly associated with hearing impairment, particularly at the high frequencies of 4,000 and 8,000 Hz.

High-frequency hearing sensitivity does not systematically imply aversion to ultrasounds in large terrestrial mammals

ABSTRACT Crop damage and vehicle collisions caused by wild ungulates require effective deterrents. Many commercial acoustic devices use ultrasonic signals, presenting them as aversive to these animals. However, unconvincing results reported in previous studies using (non-frequency modulated) ultrasounds bring their effectiveness as deterrent signals into question. Here, we explored the deterrent effectiveness of ultrasounds in several large mammalian species that are expected to perceive these high frequencies. Specifically, we tested the effect of different ultrasonic signals on red deer, peccaries, and wolves. Animals were exposed to sequences of nine acoustic signals in the 20–30 kHz frequency range, and to a lower-pitched signal (2–3 kHz). While red deer showed no aversion to ultrasonic signals (inaudible for humans), lower frequency (audible for humans) modulations increased aversive responses. Conversely, peccaries showed strong flight responses to several ultrasonic signals. Wolves also reacted to ultrasounds but did not flee. Our study confirms that ultrasonic signals are not suitable for deterring European red deer. However, our results suggest that their effectiveness in other species should be systematically tested, without assuming that their hearing frequency range is a reliable predictor of their behavioural responses to ultrasonic signals.

Cranium of Sipalocyon externus (Metatheria, Sparassodonta) with remarks on the paleoneurology of hathliacynids and insights into the Early Miocene sparassodonts of Patagonia, Argentina

In this contribution, we investigate two sparassodonts from the Sarmiento Formation (Colhuehuapian Age; Early Miocene) recovered at the Patagonian locality of Sacanana, Chubut Province, Argentina. The first specimen (MACN-Pv CH1911), identified as Sipalocyon externus, is an almost complete cranium with upper dentition. The second specimen (MACN-Pv CH40), referred to Borhyaena macrodonta, consists of a fragmentary rostral portion of the face with associated m3–m4. The cranium of S. externus was studied through µCT-scanning to investigate its internal anatomy and infer paleoecological aspects of olfaction and hearing. In general, the endocranial anatomy and encephalization quotient are like those of other metatherians. We report the presence of an accessory transverse diploic sinus that has not previously been described in marsupials. Elements of the nasal cavity (e.g., turbinals, ossified nasal septum, cribriform plate) of S. externus exhibit features that are widespread among marsupials. Sense of olfaction, as evaluated from the cribriform plate and the 3D models of the olfactory bulbs, appears to have grossly resembled that of the domestic cat, a well-researched therian proxy. The dimensions of the tympanic membrane, as estimated from the preserved ectotympanic, suggest that the optimal hearing frequency of S. externus would have been similar to that of extant carnivorous marsupials. In sum, our study suggests that S. externus was a typical small-bodied (2–3 kg) hypercarnivorous metatherian that primarily relied on vision to hunt its prey, complemented by other sensory capabilities (olfaction and hearing), in a similar manner to small felids.

Hearing and vocalizations in a small songbird, the red-cheeked cordon bleu (Uraeginthus bengalus) (L).

The auditory sensitivity of a small songbird, the red-cheeked cordon bleu, was measured using the standard methods of animal psychophysics. Hearing in cordon bleus is similar to other small passerines with best hearing in the frequency region from 2 to 4 kHz and sensitivity declining at the rate of about 10 dB/octave below 2 kHz and about 35 dB/octave as frequency increases from 4 to 9 kHz. While critical ratios are similar to other songbirds, the long-term average power spectrum of cordon bleu song falls above the frequency of best hearing in this species.

Finite element modelling of sound transmission in the Weberian apparatus of zebrafish (Danio rerio).

Zebrafish, an essential vertebrate model, has greatly expanded our understanding of hearing. However, one area that remains unexplored is the biomechanics of the Weberian apparatus, crucial for sound conduction and perception. Using micro-computed tomography (μCT) bioimaging, we created three-dimensional finite element models of the zebrafish Weberian ossicles. These models ranged from the exact size to scaled isometric versions with constrained geometry (1 to 10 mm in ossicular chain length). Harmonic finite element analysis of all 11 models revealed that the resonance frequency of the zebrafish's Weberian ossicular chain is approximately 900 Hz, matching their optimal hearing range. Interestingly, resonance frequency negatively correlated with size, while the ratio of peak displacement and difference of resonance frequency between tripus and scaphium remained constant. This suggests the transmission efficiency of the ossicular chain and the homogeneity of resonance frequency at both ends of the chain are not size-dependent. We conclude that the Weberian apparatus's resonance frequency can explain zebrafish's best hearing frequency, and their biomechanical characteristics are not influenced by isometric ontogeny. As the first biomechanical modelling of atympanic ear and among the few non-human ear modelling, this study provides a methodological framework for further investigations into hearing mechanisms and the hearing evolution of vertebrates.

Similar susceptibility to temporary hearing threshold shifts despite different audiograms in harbor porpoises and harbor seals.

When they are exposed to loud fatiguing sounds in the oceans, marine mammals are susceptible to hearing damage in the form of temporary hearing threshold shifts (TTSs) or permanent hearing threshold shifts. We compared the level-dependent and frequency-dependent susceptibility to TTSs in harbor seals and harbor porpoises, species with different hearing sensitivities in the low- and high-frequency regions. Both species were exposed to 100% duty cycle one-sixth-octave noise bands at frequencies that covered their entire hearing range. In the case of the 6.5 kHz exposure for the harbor seals, a pure tone (continuous wave) was used. TTS was quantified as a function of sound pressure level (SPL) half an octave above the center frequency of the fatiguing sound. The species have different audiograms, but their frequency-specific susceptibility to TTS was more similar. The hearing frequency range in which both species were most susceptible to TTS was 22.5-50 kHz. Furthermore, the frequency ranges were characterized by having similar critical levels (defined as the SPL of the fatiguing sound above which the magnitude of TTS induced as a function of SPL increases more strongly). This standardized between-species comparison indicates that the audiogram is not a good predictor of frequency-dependent susceptibility to TTS.

Simulating study of cochlear sensors based on PVDF organic polymer materials

Cochlear implant is an effective choice to recover hearing for patients with sensorineural deafness. With the development of society, people’s demand for cochlear implants in all aspects is increasing. Polyvinylidene fluoride (PVDF) film is a kind of high polymer with excellent properties, which has broad application prospects in the field of cochlear implant. This article uses COMSOL software to simulate PVDF films and explore the size effect on the sensor performance. The simulation results show that the eigenfrequency is linearly related to height, meanwhile the vibration mode and electric potential also vary with height. The cochlear sensor is simulated in the range of human ear-sensitive hearing frequency, and the cochlear sensor has excellent piezoelectric properties. The cochlear sensor obtained after simulation can help patients with sensorineural deafness to better identify their hearing.

Evaluation of metabolic parameters among health workers in terms of adherence to Mediterranean diet

Abstract Background The certain occupational risk factors, such as physical and mental stress from working conditions and poor diet, make healthcare workers(HCWs) a vulnerable group for obesity and non-communicable diseases(diabetes, dyslipidemia, etc.). Adopting a healthy and sustainable diet is very important in terms of both health and environmental impacts. The aim of this study was to evaluate metabolic parameters among HCWs in terms of adherence to the Mediterranean diet, which is shown to be a healthy and sustainable dietary model. Methods This cross-sectional study included 372 HCWs. The data collection tool consisted of the sociodemographic information of the participants, Mediterranean Diet Adherence Scale(MEDAS) questions, body mass index(BMI) and metabolic parameter information obtained retrospectively from hospital data. BMI≥30 kg/m2 and 25-29.9 kg/m2 were considered obese and overweight, respectively. Descriptive and inferential statistics were performed. Results 71% of the participants stated that they had not heard of the concept of ‘sustainable nutrition’ before. Of the HCWs who participated in the study, 65.3% were overweight or obese. It was found that 59.7% of the HCWs showed low adherence to the Mediterranean diet and 39.5% showed moderate adherence. Men(p &amp;lt; 0.001), those with high school education or less (p = 0.030) and those who did not think that they ate healthy(p = 0.001) had significantly lower compliance with the Mediterranean diet. BMI(p = 0.022) and HbA1c(p = 0.049) parameters were significantly lower and HDL parameter(p = 0.015) was higher in HCWs with moderate and high adherence to the Mediterranean diet. Conclusions It was observed that the frequency of hearing the concept of ‘sustainable nutrition’ and compliance with the Mediterranean diet was low among healthcare professionals. Also, it was found that the frequency of obesity, dyslipidemia, and high diabetes-related parameters were increased in those with low adherence to the Mediterranean diet. Key messages • National, EU and global policies should be developed to increase compliance with healthy and sustainable diets among health workers who play a key role in the provision of quality healthcare services. • Plans and programs to increase adherence to Mediterranean-type dietary patterns will bring significant increased health benefits related to non-communicable diseases and its risk factors.

Progress on mechanisms of age-related hearing loss.

Age-related hearing loss, or presbycusis, is a common cause of hearing loss in elderly people worldwide. It typically presents as progressive, irreversible, and usually affects the high frequencies of hearing, with a tremendous impact on the quality of life. Presbycusis is a complex multidimensional disorder, in addition to aging, multiple factors including exposure to noise, or ototoxic agents, genetic susceptibility, metabolic diseases and lifestyle can influence the onset and severity of presbycusis. With the aging of the body, its ability to clean up deleterious substances produced in the metabolic process is weakened, and the self-protection and repair function of the body is reduced, which in turn leads to irreversible damage to the cochlear tissue, resulting in the occurrence of presbycusis. Presently, oxidative stress (OS), mitochondrial DNA damage, low-grade inflammation, decreased immune function and stem cell depletion have been demonstrated to play a critical role in developing presbycusis. The purpose of this review is to illuminate the various mechanisms underlying this age-related hearing loss, with the goal of advancing our understanding, prevention, and treatment of presbycusis.

Frequency of Hypertension in Patients Diagnosed with Sensorineural Hearing Loss At a Tertiary Care Hospital

Objective: To determine frequency of hypertension in adult patients diagnosed with sensorineural hearing loss and to determine which hearing frequencies &amp; degrees are more affected with respect to grades of hypertension. Method: This is a Cross sectional study which was conducted in the ENT Department UNIT-I, Services Institute of Medical Sciences, Lahore / Services Hospital, Lahore. Duration of this study was One year from May 2020 to April2021.100 patients who met the inclusion criteria were enrolled for the study. Then history of patient for hypertension was taken and blood pressure was also checked on the spot and hypertension was labelled accordingly. Hearing thresholds were assessed via pure tone audiometry by delivering pure tones at frequencies of 125-8000hz at the intensities from 0 dB to 120 dB in 5 dB steps to check for both air and bone conduction by using Garson Stadler audiometer &amp; categorized according to WHO criteria of normal hearing &lt;25dB, mild 26-40dB, moderate 41-60 dB, severe 6180dB, profound &gt; 80 dB hearing loss. Results: Patients' mean age was 47.70±9.04 years, 67(67%) patients were male. The hypertension was found in 55(55%) patients in which grade I severity of hypertension was noted in 42(76.4 %) patients and grade II severity of hypertension was noted in 13(23.6%) patients. Conclusion: According to this study the frequency of hypertension was 55% in adult patients with sensorineural hearing loss in which 76.4% had grade I and 23.6% had grade II hypertension

Psychoacoustic Characteristics of Tinnitus in Relation to Audiometric Profile

The aim of the study was to examine the relationship between tinnitus pitch and maximum hearing loss, frequency range of hearing loss, and the edge frequency of the audiogram, as well as, to analyze tinnitus loudness at tinnitus frequency and normal hearing frequency. The study included 212 patients, aged between 21 to 75 years (mean age of 54.4 ±13.5 years) with chronic subjective tinnitus and sensorineural hearing loss. For the statistical data analysis we used Chi-square test and Fisher’s exact test with level of significance p < 0.05. Tinnitus pitch corresponding to the frequency range of hearing loss, maximum hearing loss and the edge frequency was found in 70.8%, 37.3%, and 16.5% of the patients, respectively. The majority of patients had tinnitus pitch from 3000 to 8000 Hz corresponding to the range of hearing loss (p < 0.001). The mean tinnitus pitch was 3545 Hz ±2482. The majority (66%) of patients had tinnitus loudness 4–7 dB SL. The mean sensation level at tinnitus frequency was 4.9 dB SL ±1.9, and 13 dB SL ±2.9 at normal hearing frequency. Tinnitus pitch corresponded to the frequency range of hearing loss in majority of patients. There was no relationship between tinnitus pitch and the edge frequency of the audiogram. Loudness matching outside the tinnitus frequency showed higher sensation level than loudness matching at tinnitus frequency.

The shape of water: adaptations of cochlea morphology in seals and otters

Abstract Seals (Pinnipedia) and otters (Lutrinae) are two major taxa of the mammalian order Carnivora that independently adapted to a semi-aquatic lifestyle. Their sensory capabilities, including hearing, are still not fully understood. Notably, the functional morphology of amphibious hearing presents an interesting example for studying convergent evolution. We therefore investigated the shape and dimensions of morphological traits of the inner ear and the surrounding structures involved in sound perception using Micro-Computer Tomography (µCT) data of 52 skulls belonging to 38 species of the carnivoran subgroup Caniformia. Principal component analysis (PCA) of cochlea shape variables revealed that 82% of shape variation is explained by PC1 and PC2. A number of traits (e.g. cochlea shape, reduction in cochlea turns, flattening of the cochlea, relative size of tympanum and round window) are significantly different from terrestrial Caniformia. We also found an external cochlea foramen in all Pinnipedia, which is likely related to coping with pressure compensation during diving. Finally, we demonstrate that hearing parameters, such as characteristic hearing frequency, correlate with changes in the morphological traits that separate seals and otters from other Caniformia. Our data suggest that large parts of the morphology of ear region of these semi-aquatic carnivorans have independently adapted to allow hearing in air and water.

High-frequency Noise Removal of Vintage Songs in Audio Cassettes using Signal Processing Techniques

&#x0D; From 1960 to the early 2000s, the audio cassette was one of the three most used storage devices for prerecorded music, alongside gramophone records (LPs) and compact discs (CDs). A compact cassette consists of two miniature spools, between which a magnetic tape is passed and wound. The tape head in tape recorders and cassette players is used to store and play audio tracks in these magnetic tapes by converting the electric signal to a magnetic fluctuation and vice versa. The sound quality of an audio track recorded on a compact cassette is decent. However, as these cassettes are stored in the Earth’s magnetic field for longer periods, the effect from it influences magnetic particles to change their orientation and distort the recorded audio signal. As a result, high-frequency noise is generated in the audio signal, resulting in a great disturbance when listening to songs and other audio recordings on vintage cassettes.&#x0D; 168Therefore, the removal of such noises while minimizing the impact on the original audio signal will make sure the listener gets to enjoy the original quality of the vintage audio recordings. Fourier transform of a given distorted audio file (in “wav” format) was obtained to identify the high-frequency noise using Wolfram Mathematica 12.3. Then a variable “m” was introduced to the program to identify magnitudes of high-frequency components and remove their effect on the original audio recording. A trial-and-error approach was taken to identify the adequate “m" value for each channel of a given audio signal. Vintage songs were used to evaluate the accuracy of the developed method in this study. It was identified that the suitable “m” value changes for each channel in each song. Therefore, it is impossible to state a constant value for the variable “m”. However, the accuracy of the output also depends on the hearing frequency of the person, and the audio equipment being used. As an application, this technique can be used to conserve vintage songs that were originally stored in compact cassettes and spools, because it allows the user to control the number of high-frequency components removed from the distorted audio signal.&#x0D; Keywords: Signal Processing Techniques, Fourier Transforms, Mathematica, Noise Removing,Audio Cassettes

Levels of teacher smoking and copd awareness: The case of Sanliurfa

Objective: This study aims to investigate the smoking status of teachers, the relationship between smoking and COPD, and teachers' awareness of COPD. Material and Method: 504 teachers participated in this cross-sectional study. The data was obtained through an online questionnaire utilizing a 22-question form designed by the researchers. Results: The mean age of the participants was 38.677.70 years, 47.8% of them were female, and 81.5% worked in public schools. 28% of teachers reported smoking. 24.4% of teachers reported living with a COPD patient, with 86.5% citing smoking as the major risk factor for COPD. 88.3% of participants indicated that avoiding tobacco products is crucial in preventing COPD. The majority of participants (92.7%) provided the correct response when asked about the symptoms of COPD. While 67.7% responded that PFT is used for diagnosis, 50.6% reported that it is a treatable disease, and 25% reported that inhaler medicines are used for treatment. There was a statistically significant distinction between the frequency of hearing about COPD and the specialties of the teachers. It was shown that 91.1% of smokers were aware of COPD, however, no statistical correlation was found between smoking and awareness. Conclusion: This study revealed that the prevalence of smoking among teachers in Sanliurfa was lower than previously reported in the literature. The level of awareness that COPD is a lung disease was found to be higher than in previous studies of a similar sort. It was established that awareness of the risk factors for COPD, its symptoms, preventive strategies, and the fact that COPD is a treatable disease was high. We believe that this awareness will play a crucial role in protecting students from smoking and various smoking-related diseases, such as COPD.

System of automated warning messages to creatures moving on railway tracks about the approach of rolling stock

Incidents of train collisions with creatures on railway tracks are one of the major problems for railway transport today. The scientific article presents the results of the analysis of cases of trains hitting people and creatures on railway sections. Taking this into account, the aim of the scientific work is to develop a system of automated warning messages to creatures on railway tracks of approaching trains. In the creation of the system, the notification of the approaching trains to the creatures was selected based on the frequency of hearing of the creatures that gather a lot on the railway sections. In the article, the working algorithm of the system for notifying creatures of the noise generator of the approach of trains, as well as the types of auto-blocking systems on railway sections, to start the noise generator that transmits the message of the approach of trains, if the railway tracks are equipped with the auto-blocking system, the rail chains or the railway tracks are equipped with a semi auto-blocking system connecting the road sensors that notify when the train is approaching to the contacts of the road relays, and recommendations on the selection of frequencies for the noise generator of the train approach warning system based on the hearing frequency of the creatures that gather in large numbers around the railway sections.

Prevalence of Hearing Impairment in Patients with Diabetes Mellitus

Diabetes Mellitus (DM) may be a major health problem in modern society. The disease and its complications can affect most systems of the human body. A possible complication of DM is sensorineural deafness (SNHL). Objective: To find out the prevalence of different frequencies of hearing impairment in patients with diabetes mellitus. Methods: The study design was analytic cross-sectional. The data was collected from Hameed Latif and the University of Lahore Teaching Hospital. The study took 4 months (February 2022 to July 2022). The sample size was calculated at 325 based on the prevalence (69.73%) of sensorineural hearing loss in diabetic patients through an online sample size calculator (CI: 95% and margin of error=5.00%). The Sampling technique was Non-Probability Purposive Sampling. Data analysis was done by using SPSS Version 21.0 software. The sample-included patient diagnosed with Diabetes Mellitus (DM), of both genders, aged 51-70 years, consented to inclusion in the study. Cases with external or middle ear diseases were excluded from the study. Results: The 325 diabetes mellitus patients comprised the study population, in which 36.6 % (n=119) patients had hearing loss on different frequencies, and 30.8% had mild to severe hearing loss on high frequencies. Conclusions: This study concludes that the prevalence of hearing impairment is high among patients with diabetes mellitus and has more effect on higher frequencies of hearing rather than mid and low frequencies.

Auditory sensitivity and vocal acoustics in five species of estrildid songbirds

Comparative studies of acoustic communication in clades with diverse signal features provide a powerful framework for testing relationships between perception and behaviour. We measured auditory sensitivity in five species of estrildid songbirds with acoustically distinct songs and tested whether differences aligned with species differences in song frequency content. Species were chosen based on phylogeny and differences in song acoustics. Behavioural audiograms were obtained using operant training and testing. Adult audiograms were compared across species and between sexes within a species. Juvenile and adult audiograms were compared in one species. The audiograms of adults reared by their own species and those reared and tutored by another species were compared in one species. Results showed that audiograms were similar across species and similar to previous reports of songbird auditory sensitivity. Species differed in the highest frequency detected and the frequency of peak sensitivity. While hearing frequency range was not correlated with song frequency bandwidth, the frequency of peak sensitivity was highly corelated with the frequency of peak energy in song. Sensitivity did not differ based on sex, age or tutoring experience. Our findings suggest that adaptations in songbird auditory sensitivity are largely constrained by shared peripheral and central encoding mechanisms, with species-specific perception appearing only at peak sensitivity.