Model-based hearing-restoration strategies for cochlear synaptopathy pathologies

It is well known that ageing and noise exposure are important causes of sensorineural hearing loss, and can result in damage of the outer hair cells or other structures of the inner ear, including synaptic damage to the auditory nerve (AN), i.e., cochlear synaptopathy (CS). Despite the suspected high prevalence of CS among people with self-reported hearing difficulties but seemingly normal hearing, conventional hearing-aid algorithms do not compensate for the functional deficits associated with CS. Here, we present and evaluate a number of auditory signal-processing strategies designed to maximally restore AN coding for listeners with CS pathologies. We evaluated our algorithms in subjects with and without suspected age-related CS to assess whether physiological and behavioural markers associated with CS can be improved. Our data show that after applying our algorithms, envelope-following responses and perceptual amplitude-modulation sensitivity were consistently enhanced in both young and older listeners. Speech intelligibility showed small improvements across participants, with the young group benefitting the most from processed speech. Our proposed hearing-restoration algorithms can be rapidly executed and can thus extend the application range of current hearing aids and hearables, while leaving sound amplification unaffected.

Auditory Information Accelerates the Visuomotor Reaction Speed of Elite Badminton Players in Multisensory Environments

Although vision is the dominating sensory system in sports, many situations require multisensory integration. Faster processing of auditory information in the brain may facilitate time-critical abilities such as reaction speed however previous research was limited by generic auditory and visual stimuli that did not consider audio-visual characteristics in ecologically valid environments. This study investigated the reaction speed in response to sport-specific monosensory (visual and auditory) and multisensory (audio-visual) stimulation. Neurophysiological analyses identified the neural processes contributing to differences in reaction speed. Nineteen elite badminton players participated in this study. In a first recording phase, the sound profile and shuttle speed of smash and drop strokes were identified on a badminton court using high-speed video cameras and binaural recordings. The speed and sound characteristics were transferred into auditory and visual stimuli and presented in a lab-based experiment, where participants reacted in response to sport-specific monosensory or multisensory stimulation. Auditory signal presentation was delayed by 26 ms to account for realistic audio-visual signal interaction on the court. N1 and N2 event-related potentials as indicators of auditory and visual information perception/processing, respectively were identified using a 64-channel EEG. Despite the 26 ms delay, auditory reactions were significantly faster than visual reactions (236.6 ms vs. 287.7 ms, p < 0.001) but still slower when compared to multisensory stimulation (224.4 ms, p = 0.002). Across conditions response times to smashes were faster when compared to drops (233.2 ms, 265.9 ms, p < 0.001). Faster reactions were paralleled by a lower latency and higher amplitude of the auditory N1 and visual N2 potentials. The results emphasize the potential of auditory information to accelerate the reaction time in sport-specific multisensory situations. This highlights auditory processes as a promising target for training interventions in racquet sports.

Categorical encoding of voice in human superior temporal cortex

The ability to recognize abstract features of voice during auditory perception is a complex, yet poorly understood, feat of human audition. For the listener, this occurs in near-automatic fasion to seamlessly extract complex cues from a highly variable auditory signal. Voice perception depends on specialized regions of auditory cortex, including superior temporal gyrus (STG) and superior temporal sulcus (STS). However, the nature of voice encoding at the cortical level remains poorly understoood. We leverage intracerebral recordings across human auditory cortex during presentation of voice and non-voice acoustic stimuli to examine voice encoding in auditory cortex, in eight patient-participants undergoing epilepsy surgery evaluation. We show that voice-selectivity increases along the auditory hierarchy from supratemporal plane (STP) to the STG and STS. Results show accurate decoding of vocalizations from human auditory cortical activity even in the complete absence of linguistic content. These findings show an early, less-selective temporal window of neural activity in the STG and STS followed by a sustained, strongly voice-selective window. We then developed encoding models that demonstrate divergence in the encoding of acoustic features along the auditory hierarchy, wherein STG/STS responses were best explained by voice category as opposed to the acoustic features of voice stimuli. This is in contrast to neural activity recorded from STP, in which responses were accounted for by acoustic features. These findings support a model of voice perception that engages categorical encoding mechanisms within STG and STS.

Effects of Age and Uncertainty on the Visual Speech Benefit in Noise

Purpose: Listeners understand significantly more speech in noise when the talker's face can be seen (visual speech) in comparison to an auditory-only baseline (a visual speech benefit). This study investigated whether the visual speech benefit is reduced when the correspondence between auditory and visual speech is uncertain and whether any reduction is affected by listener age (older vs. younger) and how severe the auditory signal is masked. Method: Older and younger adults completed a speech recognition in noise task that included an auditory-only condition and four auditory–visual (AV) conditions in which one, two, four, or six silent talking face videos were presented. One face always matched the auditory signal; the other face(s) did not. Auditory speech was presented in noise at −6 and −1 dB signal-to-noise ratio (SNR). Results: When the SNR was −6 dB, for both age groups, the standard-sized visual speech benefit reduced as more talking faces were presented. When the SNR was −1 dB, younger adults received the standard-sized visual speech benefit even when two talking faces were presented, whereas older adults did not. Conclusions: The size of the visual speech benefit obtained by older adults was always smaller when AV correspondence was uncertain; this was not the case for younger adults. Difficulty establishing AV correspondence may be a factor that limits older adults' speech recognition in noisy AV environments. Supplemental Material https://doi.org/10.23641/asha.16879549

Association between headache and tinnitus among medical students

ABSTRACT Background: Headache is a very common complaint and it is increasingly prevalent among university students. Tinnitus consists of subjectively perceived sounds that occur in the absence of an external auditory signal. Presence of headache and tinnitus in association has implications for therapy and prognosis, because this describes the temporality of the symptoms. Recognition of the epidemiological profile of symptomatic students might contribute to interventions. Objective: To investigate the prevalence of the association between headache and tinnitus, and to describe the epidemiological profile of the study population and the chronological order of appearance of these symptoms. Methods: Cross-sectional, observational and analytical study on a sample representative of an academic center. Data referring to the epidemiological and clinical profile of headache and tinnitus among medical students were collected through an online questionnaire built using the Google Forms tool. Results: Out of the 234 participants, 26.1% reported having tinnitus and headache (p < 0.001). The participants with headache were more likely to be women (p = 0.045), white (p = 0.009) and 21-25 years old (p = 0.356). Among right-sided, left-sided and non-unilateral headaches, tinnitus was present predominantly in the non-unilateral type, but without statistical significance. Regarding timing, 18.0% of the students said that tinnitus started before headache, 57.4% said that headache started before tinnitus and 24.6% said that they started simultaneously. Conclusions: An important association between headache and tinnitus regarding lateralization and temporality was demonstrated. Thus, these data match the presumption that headache and tinnitus have a physiopathological connection.

Effect of External Feedback on Bimanual Coordination Control in Patients with Parkinson’s Disease

Bimanual coordination control requires task-specific control of the spatial and temporal characteristics of the coupling of both upper limbs. The present study examined the effects of external feedback (i.e., auditory signal) on bimanual coordination movement during patients with Parkinson’s disease (PD). Twelve PD patients in advanced stages and 12 early stages of untreated PD patients, and 12 age-matched normal adults were instructed to perform bimanual coordination control using preference (1 Hz) and fast (1.75 Hz) speeds with metronome auditory cue. The results demonstrated that the advanced PD patients showed reduced synchronized bimanual coordination control during the anti-phase movement compared with other two groups. Moreover, the decreased movement accuracy was exhibited not only at the preference speed, but also more particularly at the fast speed with anti-phase rather than in-phase movement. This suggests that PD results in impairments in scaling the bimanual movement speed and amplitude of limb, and these deficits were more pronounced as a function of movement control speed. Overall, the current data provide evidence of the pathophysiology of the basal ganglia on the bimanual coordination movement.

Separating the Novel Speech Sound Perception of Lexical Tone Chimeras From Their Auditory Signal Manipulations: Behavioral and Electroencephalographic Evidence

Previous research has shown the novelty of lexical-tone chimeras (artificially constructed speech sounds created by combining normal speech sounds of a given language) to native speakers of the language from which the chimera components were drawn. However, the source of such novelty remains unclear. Our goal in this study was to separate the effects of chimeric tonal novelty in Mandarin speech from the effects of auditory signal manipulations. We recruited 20 native speakers of Mandarin and constructed two sets of lexical-tone chimeras by interchanging the envelopes and fine structures of both a falling/yi4/and a rising/yi2/Mandarin tone through 1, 2, 3, 4, 6, 8, 16, 32, and 64 auditory filter banks. We conducted pitch-perception ability tasks via a two-alternative, forced-choice paradigm to produce behavioral (versus physiological) pitch perception data. We also obtained electroencephalographic measurements through the scalp-recorded frequency-following response (FFR). Analyses of variances and post hoc Greenhouse-Geisser procedures revealed that the differences observed in the participants’ reaction times and FFR measurements were attributable primarily to chimeric novelty rather than signal manipulation effects. These findings can be useful in assessing neuroplasticity and developing speech-processing strategies.

Effects of degree of consonance and temporal pattern of the auditory signals on the auditory impression of warning

Disaster alerts are usually accompanied by auditory signals at the beginning. It is to be desired that the auditory signal itself produces the sense of warning. Effects of (1) degree of consonance and (2) temporal pattern of the auditory signal on the auditory impression of warning were investigated using paired-comparison tests. In the both tests, sequences of 3 triads were used as stimuli. First, 7 types of stimuli were generated by varying the degree of consonance of the triad (frequency ratio of sinusoids was varied systematically from 2:3:4, 4:5:6, 6:7:8, 8:9:10, 10:11:12, 12:13:14 through to 14:15:16). Each subject showed changes of the auditory impression of warning depending on the degree of consonance, however, variation among subjects were observed. Second, 21 types of stimuli were generated in total by changing several temporal parameters (duration of the triad, interval between the triads, duty rate of the sequence). The results indicated that the auditory impression of warning increased as the duration of the triad increased the interval between the triads decreased.

Surmising synchrony of sound and sight: Factors explaining variance of audiovisual integration in hurdling, tap dancing and drumming

Auditory and visual percepts are integrated even when they are not perfectly temporally aligned with each other, especially when the visual signal precedes the auditory signal. This window of temporal integration for asynchronous audiovisual stimuli is relatively well examined in the case of speech, while other natural action-induced sounds have been widely neglected. Here, we studied the detection of audiovisual asynchrony in three different whole-body actions with natural action-induced sounds–hurdling, tap dancing and drumming. In Study 1, we examined whether audiovisual asynchrony detection, assessed by a simultaneity judgment task, differs as a function of sound production intentionality. Based on previous findings, we expected that auditory and visual signals should be integrated over a wider temporal window for actions creating sounds intentionally (tap dancing), compared to actions creating sounds incidentally (hurdling). While percentages of perceived synchrony differed in the expected way, we identified two further factors, namely high event density and low rhythmicity, to induce higher synchrony ratings as well. Therefore, we systematically varied event density and rhythmicity in Study 2, this time using drumming stimuli to exert full control over these variables, and the same simultaneity judgment tasks. Results suggest that high event density leads to a bias to integrate rather than segregate auditory and visual signals, even at relatively large asynchronies. Rhythmicity had a similar, albeit weaker effect, when event density was low. Our findings demonstrate that shorter asynchronies and visual-first asynchronies lead to higher synchrony ratings of whole-body action, pointing to clear parallels with audiovisual integration in speech perception. Overconfidence in the naturally expected, that is, synchrony of sound and sight, was stronger for intentional (vs. incidental) sound production and for movements with high (vs. low) rhythmicity, presumably because both encourage predictive processes. In contrast, high event density appears to increase synchronicity judgments simply because it makes the detection of audiovisual asynchrony more difficult. More studies using real-life audiovisual stimuli with varying event densities and rhythmicities are needed to fully uncover the general mechanisms of audiovisual integration.

Co-occurrence Based Approach for Differentiation of Speech and Song

Discrimination of speech and song through auditory signal is an exciting topic of research. Preceding efforts were mainly discrimination of speech and non-speech but moderately fewer efforts were carried out to discriminate speech and song. Discrimination of speech and song is one of the noteworthy fragments of automatic sorting of audio signal because this is considered to be the fundamental step of hierarchical approach towards genre identification, audio archive generation. The previous efforts which were carried out to discriminate speech and song, have involved frequency domain and perceptual domain aural features. This work aims to propose an acoustic feature which is small dimensional as well as easy to compute. It is observed that energy level of speech signal and song signal differs largely due to absence of instrumental part as a background in case of speech signal. Short Time Energy (STE) is the best acoustic feature which can echo this scenario. For precise study of energy variation co-occurrence matrix of STE is generated and statistical features are extracted from it. For classification resolution, some well-known supervised classifiers have been engaged in this effort. Performance of proposed feature set has been compared with other efforts to mark the supremacy of the feature set.