The application of vagus nerve stimulation in individuals with misophonia

Stimulating the Vagus nerve helps maintain the autonomic tone, indicating stabilising any hyperactivity in the nervous system. The vagus nerve stimulation is applied in individuals with seizures, depression, sepsis, pain, obesity, cardiovascular disease, lung disease, diabetes, stroke, and traumatic brain injury. Auditory neuroscience has been widely applied in individuals with tinnitus and has been demonstrated as a successful neuromodulation technique. Individuals with peripheral lesions of the hair cells induce a maladaptive change in the plasticity resulting in hyperactivity in the auditory and non-auditory structures. In order to reduce this hyperactivity, neuromodulation techniques such as; transcranial magnetic stimulation, transcranial direct current stimulation, transcranial alternating current stimulation, transcranial random noise stimulation, neurofeedback, epidural and subdural cortical and deep brain stimulation. The vagus nerve stimulation is also one form of neuromodulation technique considered to reduce the symptoms of tinnitus. It is believed that the ramus Auricularis Nervi vagi, an afferent sensory branch of the vagus nerve, innervates the afferent sensory branch of the vagus nerve, the ramus auricularis nervi vagi also innervate the outer ear canal and parts of the auricle. This auricular branch of the vagus nerve also called Arnold's nerve, which gives a projection to the nucleus of the solitary tract. The vagus nerve stimulation in individuals with tinnitus works to activate the auricular branch of the vagus nerve to reduce its symptoms. A similar principle of vagus nerve stimulation can be tried upon in individuals with misophonia. Literatures states that individuals with misophonia have hyperactivity in their non-classical auditory pathway that can be suppressed with the help of vagus nerve stimulation. The article discusses the possible effects of vagus nerve stimulation in individuals with misophonia.

Online tests yield robust thresholds with the right auditory hygiene

Most human auditory psychophysics research has been conducted with extreme 'auditory hygiene' in carefully controlled environments, with calibrated audio equipment, and potentially hours of repetitive testing with expert, well-characterized listeners. The incompatibility of web-based platforms with such experimental regimes would seem to preclude online auditory psychophysical paradigms, where success may hinge on absolute sound presentation level, reliably estimated perceptual thresholds, and sustained motivation, attention, and vigilance. Here, we introduce and validate a set of procedures that aim to address these challenges and facilitate successful online auditory psychophysics research. First, we establish a simple means of setting sound presentation levels where online participants serve as their own sound level meter. Across a set of three experiments conducted in person, we demonstrate the stability and robustness of this volume setting procedure both 'in the wild' and in controlled settings. Second, we test participants' tone-in-noise thresholds using widely adopted online experiment platforms, and demonstrate that reliable threshold estimates can be derived in approximately one minute of testing. Third, using these sound level setting and thresholding procedures to establish participant-specific stimulus conditions, we show that frequency-selective attention can be reliably demonstrated in individual participants with an online implementation of the classic, yet challenging, probe signal psychophysics paradigm. Finally, we show how threshold and attentional measures relate to well-validated assays of online participant fatigue, task confidence, and apathy acquired at multiple timepoints across the task. In all, this demonstrates the promise of asking new questions in auditory neuroscience with classic, yet challenging, online psychophysics paradigms. The code to duplicate our results is publicly available in JavaScript, through both Pavlovia (pavlovia.org) and Gorilla (gorilla.sc).

Effect of number and placement of EEG electrodes on measurement of neural tracking of speech

Measurement of neural tracking of natural running speech from the electroencephalogram (EEG) is an increasingly popular method in auditory neuroscience and has applications in audiology. The method involves decoding the envelope of the speech signal from the EEG signal, and calculating the correlation with the envelope of the audio stream that was presented to the subject. Typically EEG systems with 64 or more electrodes are used. However, in practical applications, set-ups with fewer electrodes are required. Here, we determine the optimal number of electrodes, and the best position to place a limited number of electrodes on the scalp. We propose a channel selection strategy based on an utility metric, which allows a quick quantitative assessment of the influence of a channel (or a group of channels) on the reconstruction error. We consider two use cases: a subject-specific case, where the optimal number and position of the electrodes is determined for each subject individually, and a subject-independent case, where the electrodes are placed at the same positions (in the 10-20 system) for all the subjects. We evaluated our approach using 64-channel EEG data from 90 subjects. In the subject-specific case we found that the correlation between actual and reconstructed envelope first increased with decreasing number of electrodes, with an optimum at around 20 electrodes, yielding 29% higher correlations using the optimal number of electrodes compared to all electrodes. This means that our strategy of removing electrodes can be used to improve the correlation metric in high-density EEG recordings. In the subject-independent case, we obtained a stable decoding performance when decreasing from 64 to 22 channels. When the number of channels was further decreased, the correlation decreased. For a maximal decrease in correlation of 10%, 32 well-placed electrodes were sufficient in 91% of the subjects.

Evolving perspectives on the sources of the frequency-following response

The auditory frequency-following response (FFR) is a non-invasive index of the fidelity of sound encoding in the brain, and is used to study the integrity, plasticity, and behavioral relevance of the neural encoding of sound. In this Perspective, we review recent evidence suggesting that, in humans, the FFR arises from multiple cortical and subcortical sources, not just subcortically as previously believed, and we illustrate how the FFR to complex sounds can enhance the wider field of auditory neuroscience. Far from being of use only to study basic auditory processes, the FFR is an uncommonly multifaceted response yielding a wealth of information, with much yet to be tapped.

Effect of number and placement of EEG electrodes on measurement of neural tracking of speech

Measurement of neural tracking of natural running speech from the electroencephalogram (EEG) is an increasingly popular method in auditory neuroscience and has applications in audiology. The method involves decoding the envelope of the speech signal from the EEG signal, and calculating the correlation with the envelope of the audio stream that was presented to the subject. Typically EEG systems with 64 or more electrodes are used. However, in practical applications, set-ups with fewer electrodes are required. Here, we determine the optimal number of electrodes, and the best position to place a limited number of electrodes on the scalp. We propose a channel selection strategy based on an utility metric, which allows a quick quantitative assessment of the influence of a channel (or a group of channels) on the reconstruction error. We consider two use cases: a subject-specific case, where the optimal number and position of the electrodes is determined for each subject individually, and a subject-independent case, where the electrodes are placed at the same positions (in the 10-20 system) for all the subjects. We evaluated our approach using 64-channel EEG data from 90 subjects. In the subject-specific case we found that the correlation between actual and reconstructed envelope first increased with decreasing number of electrodes, with an optimum at around 20 electrodes, yielding 29% higher correlations using the optimal number of electrodes compared to all electrodes. This means that our strategy of removing electrodes can be used to improve the correlation metric in high-density EEG recordings. In the subject-independent case, we obtained a stable decoding performance when decreasing from 64 to 22 channels. When the number of channels was further decreased, the correlation decreased. For a maximal decrease in correlation of 10%, 32 well-placed electrodes were sufficient in 91% of the subjects.

Cortical Coding of Auditory Features

How the cerebral cortex encodes auditory features of biologically important sounds, including speech and music, is one of the most important questions in auditory neuroscience. The pursuit to understand related neural coding mechanisms in the mammalian auditory cortex can be traced back several decades to the early exploration of the cerebral cortex. Significant progress in this field has been made in the past two decades with new technical and conceptual advances. This article reviews the progress and challenges in this area of research.

Cochlear Implant Strategies and Biomaterials from Past to Future

The cochlear implant (C.I.) is a neurobionic prosthesis, being one of the greatest achievements of auditory neuroscience. Although C.I. represents the gold standard in the treatment of deafness in both the child and the adult, some problems like perception of speech in noise (atmosphere, environment), perception of music, binaural hearing remain, aspect to which improvements are expected. The article (this review) revises the road from the first attempts to cochlear implantation to today�s modern and reliable cochlear implant. Continuous improvement of existing technology both in terms of biomaterials used and in terms of speech processing and simultaneous stimulation strategies, promise with certainty the introduction of C.I. with superior performance. A look in the future is through new ideas and techniques, which await the transition from the experimental to the clinical stage in the emergence of a new generation of implants.