Neural consequences of binaural beat stimulation on auditory sentence comprehension: an EEG study.

A growing literature has shown that binaural beat (BB)-generated by dichotic presentation of slightly mismatched pure tones-improves cognition. We recently found that BB stimulation of either beta (18 Hz) or gamma (40 Hz) frequencies enhanced auditory sentence comprehension. Here, we used electroencephalography (EEG) to characterize neural oscillations pertaining to the enhanced linguistic operations following BB stimulation. Sixty healthy young adults were randomly assigned to one of three listening groups: 18-Hz BB, 40-Hz BB, or pure-tone baseline, all embedded in music. After listening to the sound for 10 min (stimulation phase), participants underwent an auditory sentence comprehension task involving spoken sentences that contained either an object or subject relative clause (task phase). During the stimulation phase, 18-Hz BB yielded increased EEG power in a beta frequency range, while 40-Hz BB did not. During the task phase, only the 18-Hz BB resulted in significantly higher accuracy and faster response times compared with the baseline, especially on syntactically more complex object-relative sentences. The behavioral improvement by 18-Hz BB was accompanied by attenuated beta power difference between object- and subject-relative sentences. Altogether, our findings demonstrate beta oscillations as a neural correlate of improved syntactic operation following BB stimulation.

The Effect of Music on Operative Anxiety markers in patients undergoing Cataract Surgery: Adual centre cross-sectional comparative study.

OBJECTIVE: To determine the effect of intraoperative music on various markers of anxiety among adult patients undergoing small incision cataract surgery. METHODS: This was a hospital-based, age-sex matched, comparative cross-sectional study of consenting 144 adult participants aged 46 years and above with operable, age-related cataracts undergoing small incision cataract surgery under local anaesthesia in two ophthalmic centres. All participants were allotted into two equal groups consisting of 72 participants in the experimental group (exposed to music of their choice) and 72 participants in the control group (no music exposure). Blood pressure, pulse rate and salivary cortisol assay levels were measured. Data obtained were analyzed using statistical package for social sciences (IBM SPSS version 23.0). RESULTS: One hundred and forty-four participants with total male-to-female ratio of 1:2.1 were studied. Gender ratio was 1:2.3 and 1:2.0 and the median age (Q1-Q3) of 65.00 (55.5-71.5) years and 65.50 (56.5-72.0) years for music and non-music groups respectively. Participants in the music group showed a statistically significant reduction in systolic blood pressure, diastolic blood pressure and pulse rate (p < 0.05) except at baseline. The mean value salivary cortisol level showed a statistically significant decrease in both groups from baseline for music (23.91ng/ml) and nonmusic (19.12ng/ml) group (p<0.001) respectively. Similarly, participants in the music group showed a statistically significant reduction of Spielberger State anxiety score after music intervention compared to control (p<0.001). CONCLUSIONS: This study demonstrated the effectiveness of music in decreasing anxiety indicators during cataract surgery with markers like salivary cortisol assay, pulse rate, systolic and diastolic blood pressure.

OBJECTIF: Déterminer l'effet de la musique intra-opératoire sur divers marqueurs d'anxiété chez les patients adultes subissant une chirurgie de la cataracte par petite incision. MÉTHODES: Il s'agissait d'une étude transversale comparative, basée à l'hôpital, appariée selon l'âge et le sexe, portant sur 144 participants adultes consentants âgés de 46 ans et plus, présentant des cataractes liées à l'âge opérables et subissant une chirurgie de la cataracte par petite incision sous anesthésie locale dans deux centres ophtalmologiques. Tous les participants ont été répartis en deux groupes égaux, soit 72 participants dans le groupe expérimental (exposé à de la musique de leur choix) et 72 participants dans le groupe témoin (pas d'exposition à la musique). La pression artérielle, la fréquence cardiaque et les taux de cortisol salivaire ont été mesurés. Les données obtenues ont été analysées à l'aid du logiciel statistique pour les sciences sociales (IBM SPSS version 23.0). RÉSULTATS: Cent quarante-quatre participants avec un rapport total d'hommes à femmes de 1:2,1 ont été étudiés. Le ratio hommes-femmes était de 1:2,3 et 1:2,0, avec un âge médian (Q1-Q3) de 65,00 (55,5-71,5) ans et 65,50 (56,5-72,0) ans pour les groupes musique et non-musique, respectivement. Les participants du groupe musique ont montré une réduction statistiquement significative de la pression artérielle systolique, de la pression artérielle diastolique et de la fréquence cardiaque (p < 0,05) sauf au départ. La valeur moyenne du taux de cortisol salivaire a montré une diminution statistiquement significative dans les deux groupes par rapport au départ pour le groupe musique (23,91 ng/ml) et le groupe non-musique (19,12 ng/ml) (p <0,001) respectivement. De même, les participants du groupe musique ont montré une réduction statistiquement significative du score d'anxiété à l'état de Spielberger après l'intervention musicale par rapport au groupe témoin (p <0,001). CONCLUSIONS: Cette étude a démontré l'efficacité de la musique dans la diminution des indicateurs d'anxiété pendant la chirurgie de la cataracte, avec des marqueurs tels que le dosage du cortisol salivaire, la fréquence cardiaque, la pression artérielle systolique et diastolique. Mots-clés: Musique binaurale, peur, anxiété, stress, chirurgie de la cataracte par petite incision, anxiolytique non pharmacologique.

Investigating the optimal stimulus to evoke the binaural interaction component of the auditory brainstem response.

Objective assessment of spatial and binaural hearing deficits remains a major clinical challenge. The binaural interaction component (BIC) of the auditory brainstem response (ABR) holds promise as a non-invasive biomarker for diagnosing such deficits. However, while comparative studies have reported robust BIC in animal models, BIC in humans can sometimes be unreliably evoked even in subjects with normal hearing. Here we explore the hypothesis that the standard methodology for collecting monaural ABRs may not be ideal for electrophysiological assessment of binaural hearing. This study aims to improve ABR BIC measurements by determining more optimal stimuli to evoke it. Building on previous methodology demonstrated to enhance peak amplitude of monaural ABRs, we constructed a series of level-dependent chirp stimuli based on empirically derived latencies of monaural-evoked ABR waves I, IV and the binaural-evoked BIC DN1, the most prominent BIC peak, in a cohort of ten chinchillas. We hypothesized that chirps designed based on BIC DN1 latency would specifically enhance across-frequency temporal synchrony in the afferent inputs leading to the binaural circuits that produce the BIC and would thus produce a larger DN1 than either traditional clicks or chirps designed to optimize monaural ABRs. Compared to clicks, we found that level-specific chirp stimuli evoked significantly greater BIC DN1 amplitudes, and that this effect persisted across all stimulation levels tested. However, we found no significant differences between BICs resulting from chirps created using binaural-evoked BIC DN1 latencies and those using monaural-evoked ABR waves I or IV. These data indicate that existing level-specific, monaural-based chirp stimuli may improve BIC detectability and reduce variability in human BIC measurements.

Comparative evaluation of anxiety level during restorative treatment using no music, monaural beats, and binaural auditory beats as audio distraction behavior guidance technique in children aged 6-12 years: A randomized clinical trial.

Background: Binaural auditory beat is an auditory illusion perceived when two different pure-tone sine waves with less than a 30 Hz difference are presented to a listener dichotically. Monaural beat stimulation is achieved by the superposition of amplitude-modulated signals of nearby frequencies to both ears simultaneously. Aim: The study aims to evaluate and compare anxiety level during restorative treatment using no music, monaural beats, and binaural auditory beats as audio distraction behavior guidance techniques in children aged 6-12 years. Settings and Design: Three-arm, parallel-group randomized study was conducted in the department of pediatric and preventive dentistry. Materials and Methods: The sample size of 45 participants was calculated and allocated into three groups as no music, monaural beats, and binaural auditory beats group. Teeth with Class I cavity in primary or permanent molars were prepared and restored. Anxiety was measured pre and postintervention using pulse oximeter and Venham's picture test. Statistical Analysis Used: Data obtained were analyzed with SPSS software version 20.0 and were carried out using one-way analysis of variance and dependent t-test and significance value < 0.05 was considered. Results: Binaural auditory beats and monaural beats showed a better reduction in anxiety levels as per Venham's picture test scores with statistically significant "P" value 0.0001 and 0.064, respectively. Likewise, binaural auditory beats showed better reduction in anxiety levels as per pulse rate scores with statistically significant "P" value 0.0001 as compared to conventional treatment technique. Conclusion: Binaural auditory beat was found to be the most effective followed by the monaural beat compared to the control group. Thus, binaural auditory beats and monaural beats can be used effectively as an essential aid to reduce anxiety in children.

Age differences in binaural and working memory abilities in school-going children.

OBJECTIVES: Binaural hearing is the interplay of acoustic cues (interaural time differences: ITD, interaural level differences: ILD, and spectral cues) and cognitive abilities (e.g., working memory, attention). The current study investigated the effect of developmental age on auditory binaural resolution and working memory and the association between them (if any) in school-going children. METHODS: Fifty-seven normal-hearing school-going children aged 6-15 y were recruited for the study. The participants were divided into three groups: Group 1 (n=17, Mage = 7.1y ± 0.72 y), Group 2 (n = 23; Mage = 10.2y ± 0.8 y), Group 3 (n = 17; Mage: 14.1 y ±1.3 y). Group 4, with normal hearing young adults (n = 20; Mage = 21.1 y± 3.2 y), was included for comparing the maturational changes in former groups with adult values. Tests of binaural resolution (ITD and ILD thresholds) and auditory working memory (forward and backward digit span and 2n-back digit) were administered to all the participants. RESULTS: Results indicated a main effect of age on spatial resolution and working memory, with the median of lower age groups (Group 1 & Group 2) being significantly poorer (p < 0.01) than the higher age groups (Group 3 & Group 4). Groups 2, 3, and 4 performed significantly better than Group 1 (p < 0.001) on the forward span and ILD task. Groups 3 and 4 had significantly better ITD (p = 0.04), backward span (p = 0.02), and 2n-back scores than Group 2. A significant correlation between scores on working memory tasks and spatial resolution thresholds was also found. On discriminant function analysis, backward span and ITD emerged as sensitive measures for segregating older groups (Group 3 & Group 4) from younger groups (Group 1 & Group 2). CONCLUSIONS: The present study showed that the ILD thresholds and forward digit span mature by nine years. However, the backward digit span score continued to mature beyond 15 y. This finding can be attributed to the influence of auditory attention (a working memory process) on the binaural resolution, which is reported to mature till late adolescence.

Interaural frequency mismatch jointly modulates neural brainstem binaural interaction and behavioral interaural time difference sensitivity in humans.

The binaural interaction component (BIC) of the auditory brainstem response (ABR) is the difference obtained after subtracting the sum of right and left ear ABRs from binaurally evoked ABRs. The BIC has attracted interest as a biomarker of binaural processing abilities. Best binaural processing is presumed to require spectrally-matched inputs at the two ears, but peripheral pathology and/or impacts of hearing devices can lead to mismatched inputs. Such mismatching can degrade behavioral sensitivity to interaural time difference (ITD) cues, but might be detected using the BIC. Here, we examine the effect of interaural frequency mismatch (IFM) on BIC and behavioral ITD sensitivity in audiometrically normal adult human subjects (both sexes). Binaural and monaural ABRs were recorded and BICs computed from subjects in response to narrowband tones. Left ear stimuli were fixed at 4000 Hz while right ear stimuli varied over a ∼2-octave range (re: 4000 Hz). Separately, subjects performed psychophysical lateralization tasks using the same stimuli to determine ITD discrimination thresholds jointly as a function of IFM and sound level. Results demonstrated significant effects of IFM on BIC amplitudes, with lower amplitudes in mismatched conditions than frequency-matched. Behavioral ITD discrimination thresholds were elevated at mismatched frequencies and lower sound levels, but also more sharply modulated by IFM at lower sound levels. Combinations of ITD, IFM and overall sound level that resulted in fused and lateralized percepts were bound by the empirically-measured BIC, and also by model predictions simulated using an established computational model of the brainstem circuit thought to generate the BIC.

Binaural Beat Effects on Attention: A Study Based on the Oddball Paradigm.

The impact of binaural beats (BBs) on human cognition and behavior remains and various methods have been used to measure their effect, including neurophysiological, psychometric, and human performance evaluations. The few approaches where the level of neural synchronicity and connectivity were measured by neuroimaging techniques have only been undertaken in spontaneous mode. The present research proposes an approach based on the oddball paradigm to study BB effect by estimating the level of attention induced by BBs. Evoked activity of 25 young adults between 19 and 24 years old with no hearing impairments nor clinical neurological history were analyzed. The experiment was conducted in two different sessions of 24.5 min. The first part consisted of 20-min BB stimulation in either theta (BBθ) or beta (BBß). After the BB stimulation, an oddball paradigm was applied in each BB condition to assess the attentional effect induced by BBs. Attention enhancement is expected for BBß with respect to BBθ. Target event related potentials (ERPs) were mainly analyzed in the time and time-frequency domains. The frequency analysis was based on continuous wavelet transform (CWT), event-related spectral perturbation (ERSP), and inter-trial phase coherence (ITPC). The study revealed that the P300 component was not significantly different between conditions (BBθ vs. BBß). However, the target grand average ERP in BBθ condition was mainly composed of 8 Hz-frequency components, appearing before 400 ms post-stimulus, and mainly on the centro-parietal regions. In contrast, the target grand average ERP in BBß condition was mainly composed of frequency components below 6 Hz, mainly appearing at 400 ms post-stimulus on the parieto-occipital regions. Furthermore, ERPs in the BBθ condition were more phase locked than the BBß condition.

Frequency-following response effect according to gender using a 10-Hz binaural beat stimulation.

BACKGROUND: Several studies have continuously investigated FFRs using binaural beat (BB) stimulations and their related effects. However, only a few studies have investigated the differences in BB stimulation effects according to basic demographic characteristics, such as gender and age. OBJECTIVE: This study aimed to determine the alpha wave activity after a 10-Hz BB stimulation and subsequently identify differences according to gender across all brain areas (frontal, central, parietal, temporal, and occipital areas). METHODS: A total of 23 healthy adults (11 male and 12 female), aged 20-29, participated in the study. For the 10-Hz BB stimulation, pure tone auditory stimuli of 250 and 260 Hz were given to the left and right ear, respectively. Through a power spectrum analysis of the phase-excluding BBs (non-BBs) and phase-including 10-Hz BBs (α-BBs), the alpha power at each brain area was estimated. These values were compared using a mixed-design ANOVA. RESULTS: With the exception of the temporal area, all other brain areas showed a significant increase in alpha power for α-BBs compared to those of non-BBs. However, the difference according to gender was not significant. CONCLUSION: The results indicated the lack of gender effects in alpha wave generation through a 10-Hz BB stimulation.

Binaural temporal coding and the middle ear muscle reflex in audiometrically normal young adults.

Noise exposure may damage the synapses that connect inner hair cells with auditory nerve fibers, before outer hair cells are lost. In humans, this cochlear synaptopathy (CS) is thought to decrease the fidelity of peripheral auditory temporal coding. In the current study, the primary hypothesis was that higher middle ear muscle reflex (MEMR) thresholds, as a proxy measure of CS, would be associated with smaller values of the binaural intelligibility level difference (BILD). The BILD, which is a measure of binaural temporal coding, is defined here as the difference in thresholds between the diotic and the antiphasic versions of the digits in noise (DIN) test. This DIN BILD may control for factors unrelated to binaural temporal coding such as linguistic, central auditory, and cognitive factors. Fifty-six audiometrically normal adults (34 females) aged 18 - 30 were tested. The test battery included standard pure tone audiometry, tympanometry, MEMR using a 2 kHz elicitor and 226 Hz and 1 kHz probes, the Noise Exposure Structured Interview, forward digit span test, extended high frequency (EHF) audiometry, and diotic and antiphasic DIN tests. The study protocol was pre-registered prior to data collection. MEMR thresholds did not predict the DIN BILD. Secondary analyses showed no association between MEMR thresholds and the individual diotic and antiphasic DIN thresholds. Greater lifetime noise exposure was non-significantly associated with higher MEMR thresholds, larger DIN BILD values, and lower (better) antiphasic DIN thresholds, but not with diotic DIN thresholds, nor with EHF thresholds. EHF thresholds were associated with neither MEMR thresholds nor any of the DIN outcomes, including the DIN BILD. Results provide no evidence that young, audiometrically normal people incur CS with impacts on binaural temporal processing.

The Relationship Between Interaural Insertion-Depth Differences, Scalar Location, and Interaural Time-Difference Processing in Adult Bilateral Cochlear-Implant Listeners.

Sensitivity to interaural time differences (ITDs) in acoustic hearing involves comparison of interaurally frequency-matched inputs. Bilateral cochlear-implant arrays are, however, only approximately aligned in angular insertion depth and scalar location across the cochleae. Interaural place-of-stimulation mismatch therefore has the potential to impact binaural perception. ITD left-right discrimination thresholds were examined in 23 postlingually-deafened adult bilateral cochlear-implant listeners, using low-rate constant-amplitude pulse trains presented via direct stimulation to single electrodes in each ear. Angular insertion depth and scalar location measured from computed-tomography (CT) scans were used to quantify interaural mismatch, and their association with binaural performance was assessed. Number-matched electrodes displayed a median interaural insertion-depth mismatch of 18° and generally yielded best or near-best ITD discrimination thresholds. Two listeners whose discrimination thresholds did not show this pattern were confirmed via CT to have atypical array placement. Listeners with more number-matched electrode pairs located in the scala tympani displayed better thresholds than listeners with fewer such pairs. ITD tuning curves as a function of interaural electrode separation were broad; bandwidths at twice the threshold minimum averaged 10.5 electrodes (equivalent to 5.9 mm for a Cochlear-brand pre-curved array). Larger angular insertion-depth differences were associated with wider bandwidths. Wide ITD tuning curve bandwidths appear to be a product of both monopolar stimulation and angular insertion-depth mismatch. Cases of good ITD sensitivity with very wide bandwidths suggest that precise matching of insertion depth is not critical for discrimination thresholds. Further prioritizing scala tympani location at implantation should, however, benefit ITD sensitivity.

Short-term efficacy of music therapy combined with α binaural beat therapy in disorders of consciousness.

Objective: To investigate the short-term effect of music therapy combined with binaural frequency difference therapy on patients with consciousness disorder. Materials and methods: Ninety patients with definite diagnosis of disorders of consciousness (DOC) were selected. These patients were randomly divided into control group, experiment 1 group and experiment 2 group, with 30 patients in each group. The control group was treated with routine clinical treatment and rehabilitation. In experiment 1 group, music therapy was added to the control group. In experimental group 2, music therapy combined with binaural α frequency difference therapy was added to the control group. All patients were assessed before and after 30 treatments. The assessment items included Glasgow Coma Scale (GCS), Coma Recovery Scale revised (CRS-R), electroencephalogram (EEG), upper somatosensory evoked potential (USEP), and brainstem auditory evoked potential (BAEP). Results: Before treatment, there were no significant differences in GCS score, CRS-R score, USEP, BAEP, and EEG scores among the three groups (P > 0.05). After 30 times of treatment, GCS score, CRS-R score, USEP, BAEP, and EEG scores in 3 groups were significantly higher than those before treatment (P < 0.05), and experimental group 2 >experimental group 1 >control group (P < 0.05). And the consciousness rate of experimental group 2 was better than experimental group 1, experimental group 1 was better than the control group and the difference was statistically significant (P < 0.05). Conclusion: Music therapy combined with binaural α frequency difference therapy is more effective in stimulating DOC patients.

Effects of Nursing Care Using Binaural Beat Music on Anxiety, Pain, and Vital Signs in Surgery Patients.

PURPOSE: This study investigated the effects of binaural beat music on anxiety, pain, and vital signs in Korean surgical patients. DESIGN: This study used a non-equivalent control group pre-and post-test design. METHODS: This study included 54 patients who underwent spinal nerve plastic surgery under local anesthesia. The experimental group listened to binaural beat music twice, using headphones (20 minutes before surgery and 30 minutes after surgery). We measured the participants' pain and anxiety levels using a visual analog scale for pain and anxiety. In addition, we checked the participants' systolic and diastolic blood pressure and heart rate using a blood pressure monitor. FINDINGS: The experimental group displayed significantly lower anxiety and pain scores than the control group after the intervention. Meanwhile, systolic and diastolic blood pressure did not show any statistically significant differences between the groups. However, the experimental group had a significantly lower pulse rate than the control group. CONCLUSION: Our research findings showed that using binaural beat music in the nursing care of surgical patients under local anesthesia can effectively reduce postoperative pain and anxiety, contributing to improved mental health and physical well-being after surgery.

The Effect of Binaural Beat Audio on Operative Pain and Anxiety in Cataract Surgery under Topical Anaesthesia: A Randomized Controlled Trial.

Background: The aim of this paper was to examine the analgesic and anxiolytic effects of binaural beat audio in patients undergoing cataract surgery under topical anaesthesia. Methods: This was a prospective, randomized controlled trial of 61 patients undergoing cataract surgery under topical anaesthesia. They were divided into two research conditions; the binaural beat audio group, and a sham-control group (ear phones with no music). Patients completed the State-Trait Anxiety Inventory questionnaire (STAI), and their blood pressure (BP) and heart rate (HR) were measured pre- and post-intervention. Intraoperative pain levels were ascertained using a visual analog scale (VAS) completed immediately after the surgery. Results: The binaural beat group had significantly lower pain scores (p < 0.001), HR (p < 0.001), diastolic BP (p = 0.003), mean arterial pressure (p = 0.007) and anxiety (p = 0.009) than the control group. Within the binaural beat group, subjects experienced a statistically significant reduction in HR (p = 0.004) and anxiety (p < 0.001) levels compared to baseline values, while all parameters, except anxiety, increased significantly in the control group. Conclusions: Binaural beat audio decreases operative pain and anxiety in cataract surgery under topical anaesthesia. It may have additional benefits in modulating the tachycardic response to stress.

Effects of Hearing Loss on Interaural Time Difference Sensitivity at Low and High Frequencies.

While many studies have reported a loss of sensitivity to interaural time differences (ITDs) carried in the fine structure of low-frequency signals for listeners with hearing loss, relatively few data are available on the perception of ITDs carried in the envelope of high-frequency signals in this population. The relevant studies found stronger effects of hearing loss at high frequencies than at low frequencies in most cases, but small subject numbers and several confounding effects prevented strong conclusions from being drawn. In the present study, we revisited this question while addressing some of the issues identified in previous studies. Participants were ten young adults with normal hearing (NH) and twenty adults with sensorineural hearing impairment (HI) spanning a range of ages. ITD discrimination thresholds were measured for octave-band-wide "rustle" stimuli centered at 500 Hz or 4000 Hz, which were presented at 20 or 40 dB sensation level. Broadband rustle stimuli and 500-Hz pure-tone stimuli were also tested. Thresholds were poorer on average for the HI group than the NH group. The ITD deficit, relative to the NH group, was similar at low and high frequencies for most HI participants. For a small number of participants, however, the deficit was strongly frequency-dependent. These results provide new insights into the binaural perception of complex sounds and may inform binaural models that incorporate effects of hearing loss.

Binaural beats reduce feeling of pain and discomfort during colonoscopy procedure in not-sedated patients: A randomized control trial.

BACKGROUND AND PURPOSE: This study aimed to determine the effect of Binaural Beats(BB)on feeling of pain, and patient comfort during colonoscopy without sedation. MATERIALS AND METHODS: It is a randomized, controlled, double-blind procedural study of 115 patients that underwent colonoscopy without sedation. The patients were randomly assigned into the experimental group (n = 42) and the control group (n = 48) that were given BB starting 5 min before and continuing until the end of the colonoscopy procedure without any intervention other than routine nursing care. Measures of the state of anxiety (VAS-Anxiety scale) administered before the procedure, and measures of feeling of pain (Visual Analogue scale VAS-pain), Satisfactory and Willingness to repeat the procedure as Likert scales were also collected soon after the colonoscopy procedure. RESULTS: Feeling of pain was lower and scores of the level of comfort were higher in the experimental group when compared to the control group (p < 0.05). CONCLUSIONS: BB is an effective and safe method for reducing pain and improving patient comfort in cases undergoing colonoscopy without sedation. Since BB method is a non-pharmacological, non-invasive, inexpensive and simple method without any side effects, it may be used to reduce the feeling of pain and discomfort for non-sedated patients undergoing colonoscopy.

Large group differences in binaural sensitivity are represented in preattentive responses from auditory cortex.

Correlated sounds presented to two ears are perceived as compact and centrally lateralized, whereas decorrelation between ears leads to intracranial image widening. Though most listeners have fine resolution for perceptual changes in interaural correlation (IAC), some investigators have reported large variability in IAC thresholds, and some normal-hearing listeners even exhibit seemingly debilitating IAC thresholds. It is unknown whether or not this variability across individuals and outlier manifestations are a product of task difficulty, poor training, or a neural deficit in the binaural auditory system. The purpose of this study was first to identify listeners with normal and abnormal IAC resolution, second to evaluate the neural responses elicited by IAC changes, and third to use a well-established model of binaural processing to determine a potential explanation for observed individual variability. Nineteen subjects were enrolled in the study, eight of whom were identified as poor performers in the IAC-threshold task. Global scalp responses (N1 and P2 amplitudes of an auditory change complex) in the individuals with poor IAC behavioral thresholds were significantly smaller than for listeners with better IAC resolution. Source-localized evoked responses confirmed this group effect in multiple subdivisions of the auditory cortex, including Heschl's gyrus, planum temporale, and the temporal sulcus. In combination with binaural modeling results, this study provides objective electrophysiological evidence of a binaural processing deficit linked to internal noise, that corresponds to very poor IAC thresholds in listeners that otherwise have normal audiometric profiles and lack spatial hearing complaints.NEW & NOTEWORTHY Group differences in the perception of interaural correlation (IAC) were observed in human adults with normal audiometric sensitivity. These differences were reflected in cortical-evoked activity measured via electroencephalography (EEG). For some participants, weak representation of the binaural cue at the cortical level in preattentive N1-P2 cortical responses may be indicative of a potential processing deficit. Such a deficit may be related to a poorly understood condition known as hidden hearing loss.

Toward applying a device to reduce motion artifact during imaging: a randomized controlled trial.

OBJECTIVE: One of the most critical problems in different types of medical imaging modalities is unwanted patient movement during imaging procedures, which mainly occurs because of stress, anxiety, and restlessness in patients, resulting in poor image quality and decreased diagnostic accuracy. METHODS: This prospective, randomized, double-blinded, controlled trial comprised 267 patients who underwent MPI, randomly divided into three groups; Group I: streaming music with a special binaural beat frequency (MBB); Group II: streaming simple music (SM) and Group III: control group. Anxiety level was determined by the Depression Anxiety Stress-Scale (DASS) questionnaire and heart rate was monitored. RESULTS: Stress and anxiety scores were significantly lower in the MBB group compared with both SM and control group (P˂0.0001). Additionally, a significant decrease in heart rate of patients who were in the MBB group in comparison with the SM (p = 0.005) and control group (P = 0.018) was observed. The study revealed a significant decrease in motion artifact in the MBB group compared with the SM (P = 0.003) and control (P˂0.0001) groups. CONCLUSIONS: Using the proposed device capable of streaming special binaural beat frequency embedded music can cause a significant reduction in anxiety level, heart rate, and consequently motion artifact.

Cortical Processing of Binaural Cues as Shown by EEG Responses to Random-Chord Stereograms.

Spatial hearing facilitates the perceptual organization of complex soundscapes into accurate mental representations of sound sources in the environment. Yet, the role of binaural cues in auditory scene analysis (ASA) has received relatively little attention in recent neuroscientific studies employing novel, spectro-temporally complex stimuli. This may be because a stimulation paradigm that provides binaurally derived grouping cues of sufficient spectro-temporal complexity has not yet been established for neuroscientific ASA experiments. Random-chord stereograms (RCS) are a class of auditory stimuli that exploit spectro-temporal variations in the interaural envelope correlation of noise-like sounds with interaurally coherent fine structure; they evoke salient auditory percepts that emerge only under binaural listening. Here, our aim was to assess the usability of the RCS paradigm for indexing binaural processing in the human brain. To this end, we recorded EEG responses to RCS stimuli from 12 normal-hearing subjects. The stimuli consisted of an initial 3-s noise segment with interaurally uncorrelated envelopes, followed by another 3-s segment, where envelope correlation was modulated periodically according to the RCS paradigm. Modulations were applied either across the entire stimulus bandwidth (wideband stimuli) or in temporally shifting frequency bands (ripple stimulus). Event-related potentials and inter-trial phase coherence analyses of the EEG responses showed that the introduction of the 3- or 5-Hz wideband modulations produced a prominent change-onset complex and ongoing synchronized responses to the RCS modulations. In contrast, the ripple stimulus elicited a change-onset response but no response to ongoing RCS modulation. Frequency-domain analyses revealed increased spectral power at the fundamental frequency and the first harmonic of wideband RCS modulations. RCS stimulation yields robust EEG measures of binaurally driven auditory reorganization and has potential to provide a flexible stimulation paradigm suitable for isolating binaural effects in ASA experiments.

Binaural sound therapy for tinnitus treatment: A psychometric and neurophysiological evaluation.

INTRODUCTION: Tinnitus is an annoying buzz that manifests itself in many ways. In addition, it can provoke anxiety, stress, depression, and fatigue. The acoustic therapies have become the most commonly applied treatment for tinnitus, either self-administered or clinically prescribed. Binaural Sound Therapy (BST) and Music Therapy (MT) aim to reverse the neuroplasticity phenomenon related to tinnitus by adequately stimulating the auditory path-way. The goal of this research is to evaluate the feasibility of applying BST for tinnitus treatment by comparing its effect with MT effect. MATERIALS AND METHODS: 34 patients with tinnitus from 29 to 60 years were informed about the experimental procedure and consented their participation. Patients were divided into two groups: 1) MT and 2) BST. They applied their sound-based treatment for one hour every day along eight weeks. Each treatment was adjusted to Hearing Loss (HL) and tinnitus characteristics of each participant. To record EEG data, a bio-signal amplifier with sixteen EEG channels was used. The system recorded data at a sampling frequency of 256 Hz within a bandwidth between 0.1 and 100 Hz. RESULTS: The questionnaire-monitoring reported that MT increased tinnitus perception in 30% of the patients, and increased anxiety and stress in 8% of them. Regarding EEG-monitoring, major neural synchronicity over the frontal lobe was found after the treatment. In the case of BST reduced stress in 23% of patients. Additionally, BST reduced tinnitus perception similar to MT (15% of patients). With respect to EEG-monitoring, slightly major neural synchronicity over the right frontal lobe was found after the treatment. CONCLUSIONS: MT should be applied with caution since it could be worsening the tinnitus sufferer condition. On the other hand, BST is recommended for tinnitus sufferers who have side effects concerning stress but no anxiety.

Can binaural beats facilitate autonomic recovery following exposure to an acute stressor?

BACKGROUND AND PURPOSE: Binaural beats are seen as a new type of 'digital-drug'. The aim of this study was to determine if binaural beats could facilitate physiological recovery from a mental stressor. MATERIALS AND METHODS: 92 adults were exposed five times each to a 2-min mental stressor and a subsequent 4-min rest period containing silence or 1-of-4 examples of binaural beats (2, 5, 10, and 24 Hz). Physiological recovery across the five rest periods, as measured using skin conductance, heart rate, and breathing, were compared using one-way analysis of variance. RESULTS: Binaural beats were linked to enhanced physiological recovery relative to silence. However, the expected pattern of results whereby lower frequency binaural beats would be associated with greater physiological recovery, was not observed. CONCLUSION: Our findings do not support a relationship between binaural beats and systematic changes in emotional states as measured physiologically. On the basis of our results the acute administration of binaural beats in primary care to lower sympathetic arousal cannot yet be considered an evidence-based practice.