Test-Retest Reliability of Binaural Interaction Component (BIC) Using Speech and Non-Speech Evoked ABR

Background and Objective: Binaural hearing serves as an advantage in daily communication by facilitating better localization of sounds and perception of speech in the presence of noise. BIC of ABR has been used to understand the binaural representation of different stimuli, such as transient clicks, and complex signals, such as speech. The present study aimed to investigate the test-retest reliability of the binaural interaction component for click and speech evoked ABR. Methods: 30 individuals with normal hearing served as participants for the present study. ABR for click and speech stimuli (/da/) were recorded from these participants in monaural and binaural conditions. BIC was calculated using the formula: BIC = (L + R)- BI where, L + R is the sum of the left and right evoked potentials obtained with monaural stimulation, and BI is the response acquired from binaural stimulation. To investigate reliability, all the participants underwent three recording sessions. Session 1 and session 2 (intra-session) were carried out on the same day, separately. Whereas, session 3 (inter-session) was carried out after a minimum gap of 3 - 5 days after the first session. Intraclass correlation was used to investigate the test-retest reliability of click and speech evoked BIC across the three sessions. Results: The test-retest reliability for BICclick was found to be excellent for latency measures and fair to good for amplitude measures. BICspeech was found to be fair to good, except for BIC-3. Conclusion: The results of the present study indicate that the reliability of BICclick is better than that of BICspeech. These results suggest that the clinical utility of BICspeech should be exerted with caution.

Challenges and innovations in the use of active methodologies in undergraduate medical courses

Background Conscious perception of oneself and others in their complexity and subjectivity allows the approach of trying to understand the human being to overcome the labeling stigma of the disease. For the educator, it is unique to guide the way that can transform a gap in the undergraduate medical education into a possibility of positive action. It was in this sense that the perception workshop was developed based on the concept of Integrated Gestalt Therapy. Teachers of the Communication, Leadership, and Management Skills discipline invited undergraduate medical students to stimulate the five senses. For sensory experiments, 6 stations were used in the classroom. Season 1 - View: Photos from the 'More Medical Programs' and deductive interpretation were posted on the board for observation. Season 2 - Tact: Blindfolded they handled four types of objects with different textures. Season 3 - Movement: two photos of yoga position (medium and high complexity) for imitation. Station 4 - hearing: auditory processing through binaural stimulation with computer-attached headset. Season 5 - nose and taste memory: through spices, leaves and dried fruits, the nostrils were stimulated for identification and recognition. Station 6 - Speech: Voice Lab through Voice Spectrogram Analysis (Praat). Results Faced with activities like this, we can see that students go through a process of breaking paradigms, which significantly influences their way of thinking. This training is part of continuing education through the perspective of the knowledge spiral. With the evolution of the undergraduate years, the student will be able to refine and deepen their reflections in a continuous process. Conclusions This work represents a breakthrough in the field of health education. Humanized professionals, aware of their skills and abilities, with actions aimed at the well-being of the population, in a generalist, critical and reflective manner. Key messages The impact generated on the assisted population have been observed when this new professional profile is inserted in health services. This workshop represents a breakthrough in the field of training health professionals with actions focused on the welfare of the population in a generalist, critical and reflexive manner.

Internally coupled middle ears enhance the range of interaural time differences heard by the chicken

Interaural time differences (ITD) are one of several principle cues for localizing sounds. However, ITD are in the sub-millisecond range for most animals. Because the neural processing of such small ITDs pushes the limit of temporal resolution, the precise ITD-range for a given species and its usefulness - relative to other localization cues - was a powerful selective force in the evolution of the neural circuits involved. Birds and other non-mammals have internally coupled middle ears working as pressure-difference receivers that may significantly enhance ITD, depending on the precise properties of the interaural connection. Here, the extent of this internal coupling was investigated in chickens, specifically under the same experimental conditions as typically used in neurophysiology of ITD-coding circuits, i.e. with headphone stimulation. Cochlear microphonics (CM) were recorded simultaneously from both ears of anesthetized chickens under monaural and binaural stimulation, using pure tones from 0.1 to 3 kHz. Interaural transmission peaked at 1.5 kHz at a loss of only −5.5 dB; the mean interaural delay was 264 μs. CM amplitude strongly modulated as a function of ITD, confirming significant interaural coupling. The “ITD heard” derived from the CM phases in both ears showed enhancement, compared to the acoustic stimuli, by a factor of up to 1.8. However, the closed sound delivery systems impaired interaural transmission at low frequencies (< 1 kHz). We identify factors that need to be considered when interpreting neurophysiological data obtained under these conditions, and relating them to the natural free-field condition.Summary statementThe interaural time differences that chickens can use for sound localization are significantly greater than their small head size suggests. Closed-system sound stimulation can, however, produce complex artefacts.

COMPLEXITY-BASED ANALYSIS OF THE DIFFERENCE IN SPEECH-EVOKED AUDITORY BRAINSTEM RESPONSES (s-ABRs) BETWEEN BINAURAL AND MONAURAL LISTENING CONDITIONS

One of the important research areas in behavioral neuroscience is to investigate the brain response to different types of stimuli. Speech-evoked Auditory Brainstem Response (s-ABR) is a tool to study the brainstem processing of speech sounds. During years, scientists have employed different techniques to analyze the influence of auditory stimulation on s-ABR signal in different conditions. One important category of works, which aroused the attention of scientists, has been the analysis of the variations of s-ABR signal in binaural and monaural stimulations. In this research, we analyze the variations of s-ABR signal due to auditory stimulation in the form of speech syllable, in binaural and monaural (right or left ear) listening conditions. For this purpose, we have employed fractal analysis in order to analyze the complexity of s-ABR signal in three stimulation conditions (both ears, right ear, left ear). The results of our analysis showed that s-ABR signal in case of binaural stimulation shows significant lower complexity compared to monaural stimulation. In comparison of s-ABR signals between left ear and right ear using fractal dimension, no significant difference was observed.

Changes in response characteristics of cortical auditory evoked potentials in bilateral cochlear implantees

<p class="abstract"><strong>Background:</strong> Cochlear implants (CIs) represents the most successful intervention to restore hearing in profoundly hearing impaired children and adults. An objective measures such as cortical auditory evoked potentials (CAEPs) would provide more insights to the auditory process involved in post implantation. Aim of the study was to profile the change in response characteristics of CAEPs in simultaneous binaural cochlear implantees. Objective was to measure change in latency and amplitude in monoaural and binaural condition for speech stimulus with change in intensities.</p><p class="abstract"><strong>Methods:</strong> Ours study is an observational retrospective study done at a tertiary ENT referral centre in south India, between Jan 2014 to Dec 2015. Out of total 15 patients with bilateral cochlear implantation, 7 consecutive bilateral simultaneous cochlear implantees with chronological age between 2-6 years were included in the study. Only pre-lingual congenital hearing loss children with no syndromic associations and normal cochlear anatomy were included while, peri-lingual, post-lingual children and children with sequential bilateral implantation were excluded from the study. </p><p class="abstract"><strong>Results:</strong> Amplitude of P1 was higher for binaural stimulation compared to monoaural stimulation. Latency of P1 was smaller for binaural compared to monoaural stimulus. In monaural stimulation the latency of P1 was smaller in right ear compared to left ear. However the difference between the right ear, left ear and binaural conditions were not statistically significant. Ours is a preliminary study and more bilateral implantees will be included in future studies to give more power to the study.</p><p><strong>Conclusions:</strong> We suggest that CAEPs can be used as a useful objective tool for assessment of post CI outcome.</p>

Simultaneous recording of cervical and ocular vestibular-evoked myogenic potentials

ObjectiveTo increase clinical application of vestibular-evoked myogenic potentials (VEMPs) by reducing the testing time by evaluating whether a simultaneous recording of ocular and cervical VEMPs can be achieved without a loss in diagnostic sensitivity and specificity.MethodsSimultaneous recording of ocular and cervical VEMPs on each side during monaural stimulation, bilateral simultaneous recording of ocular VEMPs and cervical VEMPs during binaural stimulation, and conventional sequential recording of ocular and cervical VEMPs on each side using air-conducted sound (500 Hz, 5-millisecond tone burst) were compared in 40 healthy participants (HPs) and 20 patients with acute vestibular neuritis.ResultsEither simultaneous recording during monaural and binaural stimulation effectively reduced the recording time by ≈55% of that for conventional sequential recordings in both the HP and patient groups. The simultaneous recording with monaural stimulation resulted in latencies and thresholds of both VEMPs and the amplitude of cervical VEMPs similar to those found during the conventional recordings but larger ocular VEMP amplitudes (156%) in both groups. In contrast, compared to the conventional recording, simultaneous recording of each VEMP during binaural stimulation showed reduced amplitudes (31%) and increased thresholds for cervical VEMPs in both groups.ConclusionsThe results of simultaneous recording of cervical and ocular VEMPs during monaural stimulation were comparable to those obtained from the conventional recording while reducing the time to record both VEMPs on each side.ClinicalTrials.gov identifierNCT03049683.

Evaluation of central vestibular syndrome in dogs using brainstem auditory evoked responses recorded with surface electrodes

ABSTRACT The present study aimed to analyse the wave morphology, amplitude, latency, and intervals of the brainstem auditory evoked responses (BAERs) in dogs with central vestibular syndrome (CVS) recorded with surface electrodes. Ten dogs with CVS were examined by mono- and binaural stimulation, using the Neuropack electrodiagnostic system, with stimulus intensities of 90 dBSPL. BAERs examinations revealed morphological changes of waves I, II, III, and V and decreased amplitudes of all waves in 7/10 dogs. P values obtained were = 0.014 for wave I amplitude, 0.031 for II, and III and 0.032 for V. Comparing the latencies of waves I, II, III, and V generated by right and left monoaural stimulation in dogs with CVS, we did not observe significant differences (P>0.05). No statistical differences were observed for BAERs latencies of the waves recorded after binaural and monaural stimulation (left or right). As far as we know, this is the first study of BAERs using surface electrodes, obtained from dogs with CVS.

The Effect of Repetition Rate on Air-Conducted Ocular Vestibular Evoked Myogenic Potentials (oVEMPs)

Purpose Ocular vestibular evoked myogenic potentials (oVEMPs) are used to describe utricular/superior vestibular nerve function; however, optimal recording parameters have not been fully established. This study investigated the effect of repetition rate on air-conducted oVEMPs. Method Ten healthy adults were evaluated using 500-Hz tone bursts (4-ms duration, Blackman gating, 122 dB pSPL). Four repetition rates were used (1.6, 4.8, 8.3, and 26.6 Hz) and resulting oVEMP response presence, amplitude, amplitude asymmetry, and n1/p1 latency were assessed. Results Response presence was significantly reduced for 26.6 Hz using monaural stimulation and for 8.3 Hz and 26.6 Hz for binaural stimulation. For monaural stimulation using 1.6, 4.8, and 8.3 Hz, no significant differences were noted for amplitude or latency. Responses obtained using binaural stimulation demonstrated a significant effect of rate on amplitude, with 8.3 Hz producing significantly reduced amplitude. Binaural amplitudes were significantly larger than monaural contralateral responses but with reduced response presence. No significant differences were noted for latency or amplitude asymmetry. Conclusion Using repetition rates of approximately 5 Hz or less may produce more consistent oVEMP response presence with minimal effects on amplitude for monaural or binaural recordings.

Effect of Binaural Stimulation on Attention and EEG

When two pure tones of slightly different frequency are presented separately to each ear, the listener perceives a third single tone with amplitude variations at a frequency that equals the difference between the two tones; this perceptual illusion is known as the binaural auditory beat (BB). There are anecdotal reports that suggest that the binaural beat can entrain EEG activity and may affect the arousal levels, although few studies have been published. There is a need for double-blind, well-designed studies in order to establish a solid foundation for these sounds, as most of the documented benefits come from self-reported cases that could be affected by placebo effect. As BBs are a cheap technology (it even exists a free open source programmable binaural- beat generator on the Internet named Gnaural), any achievement in this area could be of public interest. The aim in our research was to explore the potential of BBs in a particular field: tasks that require focus and concentration. In order to detect changes in the brain waves that could relate to any particular improvement, EEG recordings of a small sample of individuals were also obtained. In this study we compare the effect of different binaural stimulation in 7 EEG frequency ranges. 78 participants were exposed to 20-min binaural beat stimulation. The effects were obtained both quali- tative with cognitive test and quantitative with EEG analysis. Results suggest no significant statistical improvement in 20-min stimulation.