The sound localization behavior of the nocturnally hunting barn owl and its underlying neural computations is a textbook example of neuroethology. Differences in sound timing and level at the two ears are integrated in a series of well-characterized steps, from brainstem to inferior colliculus (IC), resulting in a topographical neural representation of auditory space. It remains an important question of brain evolution: How is this specialized case derived from a more plesiomorphic pattern? The present study is the first to match physiology and anatomical subregions in the non-owl avian IC. Single-unit responses in the chicken IC were tested for selectivity to different frequencies and to the binaural difference cues. Their anatomical origin was reconstructed with the help of electrolytic lesions and immunohistochemical identification of different subregions of the IC, based on previous characterizations in owl and chicken. In contrast to barn owl, there was no distinct differentiation of responses in the different subregions. We found neural topographies for both binaural cues but no evidence for a coherent representation of auditory space. The results are consistent with previous work in pigeon IC and chicken higher-order midbrain and suggest a plesiomorphic condition of multisensory integration in the midbrain that is dominated by lateral panoramic vision.

BACKGROUND: Sensory disability in older adults is associated with increased rates of depressive symptoms and loneliness. Here, we examined the impact of hearing, vision, and olfaction disability on mental health outcomes in older US adults.
METHODS: We studied respondents from the first three rounds (2005/6, 2010/11, and 2015/16) of the National Social Life, Health and Aging Project, a nationally representative, longitudinal study of older US adults. Sensory function was assessed by structured interviewer ratings (hearing and vision) and objective assessment (olfaction). Cox proportional hazards models and one degree of freedom tests for trend were utilized to analyze the relationships between sensory disability and self-rated mental health, frequent depressive symptoms, frequent perceived stress, frequent anxiety symptoms, and frequent loneliness symptoms over time, adjusting for demographics, health behaviors, comorbidities, and cognitive function.
RESULTS: We analyzed data from 3940 respondents over 10 years of follow-up. A greater number of sensory disabilities was associated with greater hazard of low self-rated mental health, frequent depressive symptoms, frequent perceived stress, and frequent loneliness symptoms over time (p ≤ 0.003, all). After adjusting for covariates, older adults with a greater number of sensory disabilities had greater hazard of low self-rated mental health (HR = 1.22, CI = [1.08, 1.38], p = 0.002) and loneliness symptoms (HR = 1.13, CI = [1.05, 1.22], p = 0.003) over time in our tests for trend. In our Cox proportional hazards model, older adults with vision disability had greater hazard of low self-rated mental health (HR = 1.34, 95% CI = [1.05, 1.72], p = 0.02) and loneliness symptoms (HR = 1.21, CI = [1.04, 1.41], p = 0.01).
CONCLUSIONS: Older US adults with greater numbers of sensory disabilities face worse subsequent mental health. Future longitudinal studies dissecting the relationship of all five classical senses will be helpful in further understanding how improving sensory function might improve mental health in older adults.

Palatine and pharyngeal tonsil hypertrophy may lead to dysfunction of the auditory tube due to a propensity for infection, potentially giving rise to otitis media. This is a quantitative and longitudinal study, developed from 2019 to 2021, at the State University of Campinas (UNICAMP). The studied sample comprised 15 participants aged 5 to 12 years (mean 7.9 years), 12 male and 3 female, arranged into two groups: children diagnosed with pharyngeal and/or palatine tonsil hypertrophy who were candidates for surgery (G1), and children who were later evaluated after surgery (G2). As part of the test, an otoscopy and measurements of logoaudiometry, pure-tone threshold audiometry, wideband tympanometry (ambient and peak pressure), and otoacoustic emissions (TEOAEs and DPOAEs, both at ambient and peak pressure) were all performed. There were statistically significant differences between phases in pure-tone audiometry, in terms of 226 Hz tympanometry, wideband tympanometry in peak pressure conditions, in the amplitude measurement TEOAEs in both pressure conditions, in DPOAEs in ambient pressure conditions, and in the signal/noise measurement in both pressures in DPOAEs. Overall, it was found that hearing tests were different for subjects with palatine and pharyngeal tonsil hypertrophy compared to the post-surgical group.

During behavior, the motor cortex sends copies of motor-related signals to sensory cortices. Here, we combine closed-loop behavior with large-scale physiology, projection-pattern-specific recordings, and circuit perturbations to show that neurons in mouse secondary motor cortex (M2) encode sensation and are influenced by expectation. When a movement unexpectedly produces a sound, M2 becomes dominated by sound-evoked activity. Sound responses in M2 are inherited partially from the auditory cortex and are routed back to the auditory cortex, providing a path for the reciprocal exchange of sensory-motor information during behavior. When the acoustic consequences of a movement become predictable, M2 responses to self-generated sounds are selectively gated off. These changes in single-cell responses are reflected in population dynamics, which are influenced by both sensation and expectation. Together, these findings reveal the embedding of sensory and expectation signals in motor cortical activity.

Objectives: To evaluate the effectiveness of ofloxacin ear drops versus no intervention in the repair of traumatic tympanic membrane (TM) perforations from randomized controlled trials (RCTs). Data Sources: Medline/PubMed, CENTRAL, Clinical Trials.Gov, and Google Scholar. Study Selection: Inclusion criteria: (1) English language; (2) RCT studies; (3) reported the outcomes on the application of ofloxacin and outcomes of spontaneous healing. Exclusion criteria: (1) studies without a control group; (2) patient with severe otologic disease such as chronic suppurative otitis media or ossicular disruption or patients with craniocerebral injury; (3) studies with no pretreatment values or single-arm clinical studies. Data Extraction: Country, year of publication, number of participants in each arm, patient characteristics such as age, sex, intervention details, laterality, cause of TM perforation, position of perforation, follow-up time, hearing gain, rate of TM closure, and closure time. Results: A total of 6 RCTs studies were analyzed. A total of 502 participants were included; the relative risk for closure rate of ofloxacin treatment was 1.18 [95% confidence interval (CI), 1.08 to 1.28, P < .001] and the mean difference (MD) for healing time was -18.4 (95% CI, -19.96 to -16.82, P < .001), suggesting ofloxacin has a significant effect on closure of TM perforations. However, no clinically significant effect in hearing (SMD: 0.21, 95% CI, 0.02 to 0.40, P = .03) was seen in ofloxacin group. Also, patients in the ofloxacin group were associated with a 13% reduction in the risk of infections compared to their observation-assigned counterparts, but this estimate was not statistically significant. Conclusion: Ofloxacin use in patients with traumatic TM perforation is effective in reducing healing time and increasing rate of TM perforation closure. No evidence of increased risk of hearing loss or infection rates are encountered when ofloxacin is prescribed to patients with traumatic TM perforation.

The level-of-processing (LoP) hypothesis postulates that transition from unaware to aware visual stimuli is either graded or dichotomous depending on the depth of stimulus processing. Humans can be progressively aware of the low-level features, such as colors or shapes, while the high-level features, such as semantic category, enter consciousness in an all-or none fashion. Unlike in vision, sounds always unfold in time, which might require mechanisms dissimilar from visual processing. We tested the LoP hypothesis in hearing for the first time by presenting participants with words of different categories, spoken in different pitches near the perceptual threshold. We also assessed whether different electrophysiological correlates of consciousness, the auditory awareness negativity (AAN) and late positivity (LP), were associated with LoP. Our findings indicate that LoP also applies to the auditory modality. AAN is an early correlate of awareness independent of LoP, while LP was modulated by awareness, performance accuracy and the level of processing.

Locating sound sources such as prey or predators is critical for survival in many vertebrates. Terrestrial vertebrates locate sources by measuring the time delay and intensity difference of sound pressure at each ear1-5. Underwater, however, the physics of sound makes interaural cues very small, suggesting that directional hearing in fish should be nearly impossible6. Yet, directional hearing has been confirmed behaviourally, although the mechanisms have remained unknown for decades. Several hypotheses have been proposed to explain this remarkable ability, including the possibility that fish evolved an extreme sensitivity to minute interaural differences or that fish might compare sound pressure with particle motion signals7,8. However, experimental challenges have long hindered a definitive explanation. Here we empirically test these models in the transparent teleost Danionella cerebrum, one of the smallest vertebrates9,10. By selectively controlling pressure and particle motion, we dissect the sensory algorithm underlying directional acoustic startles. We find that both cues are indispensable for this behaviour and that their relative phase controls its direction. Using micro-computed tomography and optical vibrometry, we further show that D. cerebrum has the sensory structures to implement this mechanism. D. cerebrum shares these structures with more than 15% of living vertebrate species, suggesting a widespread mechanism for inferring sound direction.

Spoken language development after pediatric cochlear implantation requires rapid and efficient processing of novel, degraded auditory signals and linguistic information. These demands for rapid adaptation tax the information processing speed ability of children who receive cochlear implants. This study investigated the association of speed of information processing ability with spoken language outcomes after cochlear implantation in prelingually deaf children aged 4-6 years. Two domain-general (visual, non-linguistic) speed of information processing measures were administered to 21 preschool-aged children with cochlear implants and 23 normal-hearing peers. Measures of speech recognition, language (vocabulary and comprehension), nonverbal intelligence, and executive functioning skills were also obtained from each participant. Speed of information processing was positively associated with speech recognition and language skills in preschool-aged children with cochlear implants but not in normal-hearing peers. This association remained significant after controlling for hearing group, age, nonverbal intelligence, and executive functioning skills. These findings are consistent with models suggesting that domain-general, fast-efficient information processing speed underlies adaptation to speech perception and language learning following implantation. Assessment and intervention strategies targeting speed of information processing may provide better understanding and development of speech-language skills after cochlear implantation.

OBJECTIVE: The long-term preservation of residual hearing after cochlear implantation has become a major goal over the past few years. The aim of the present study was to evaluate residual hearing in the long-term follow-up using mid-scala electrodes.
METHODS: In this retrospective, single-center study, we collected data from 27 patients who were implanted between 2014 and 2015 with residual hearing in the low-frequency range using a mid-scala electrode. Measurements of the hearing thresholds were carried out directly postoperatively (day 1 after surgery) and in the long-term follow-up 43.7 ± 6.9 months. The calculation of the extent of audiological hearing preservation was determined using the HEARRING group formula by Skarsynski.
RESULTS: Postoperative preservation of residual hearing was achieved in 69.2% of the cases in the low-frequency range between 250 Hz and 1 kHz, of which 89.5% of the patients had frequencies that suggested using electroacoustic stimulation (EAS). In the long-term follow-up, 30.8% of the patients showed residual hearing; however, 57.1% had apparently benefited from EAS.
CONCLUSIONS: Preservation of residual hearing is feasible in the long term using mid-scala electrodes. Postoperatively, there is over the half of patients who benefit from an EAS strategy. The long-term follow-up shows a certain decrease in residual hearing. However, these results are comparable to studies relating to other types of electrodes. Further research should be conducted in future to better evaluate hearing loss in long-term follow-up, compared to direct postoperative audiological results.

UNASSIGNED: Age-related hearing difficulties have a complex etiology that includes degenerative processes in the sensory cochlea. The cochlea comprises the start of the afferent, ascending auditory pathway, but also receives efferent feedback innervation by two separate populations of brainstem neurons: the medial olivocochlear and lateral olivocochlear pathways, innervating the outer hair cells and auditory-nerve fibers synapsing on inner hair cells, respectively. Efferents are believed to improve hearing under difficult conditions, such as high background noise. Here, we compare olivocochlear efferent innervation density along the tonotopic axis in young-adult and aged gerbils (at ~50% of their maximum lifespan potential), a classic animal model for age-related hearing loss.
UNASSIGNED: Efferent synaptic terminals and sensory hair cells were labeled immunohistochemically with anti-synaptotagmin and anti-myosin VIIa, respectively. Numbers of hair cells, numbers of efferent terminals, and the efferent innervation area were quantified at seven tonotopic locations along the organ of Corti.
UNASSIGNED: The tonotopic distribution of olivocochlear innervation in the gerbil was similar to that previously shown for other species, with a slight apical cochlear bias in presumed lateral olivocochlear innervation (inner-hair-cell region), and a broad mid-cochlear peak for presumed medial olivocochlear innervation (outer-hair-cell region). We found significant, age-related declines in overall efferent innervation to both the inner-hair-cell and the outer-hair-cell region. However, when accounting for the age-related losses in efferent target structures, the innervation density of surviving elements proved unchanged in the inner-hair-cell region. For outer hair cells, a pronounced increase of orphaned outer hair cells, i.e., lacking efferent innervation, was observed. Surviving outer hair cells that were still efferently innervated retained a nearly normal innervation.
UNASSIGNED: A comparison across species suggests a basic aging scenario where outer hair cells, type-I afferents, and the efferents associated with them, steadily die away with advancing age, but leave the surviving cochlear circuitry largely intact until an advanced age, beyond 50% of a species\' maximum lifespan potential. In the outer-hair-cell region, MOC degeneration may precede outer-hair-cell death, leaving a putatively transient population of orphaned outer hair cells that are no longer under efferent control.