External Auditory Stimuli Research Articles

From Sound to Movement: Mapping the Neural Mechanisms of Auditory-Motor Entrainment and Synchronization.

Humans exhibit a remarkable ability to synchronize their actions with external auditory stimuli through a process called auditory-motor or rhythmic entrainment. Positive effects of rhythmic entrainment have been demonstrated in adults with neurological movement disorders, yet the neural substrates supporting the transformation of auditory input into timed rhythmic motor outputs are not fully understood. We aimed to systematically map and synthesize the research on the neural correlates of auditory-motor entrainment and synchronization. Following the PRISMA-ScR guidelines for scoping reviews, a systematic search was conducted across four databases (MEDLINE, Embase, PsycInfo, and Scopus) for articles published between 2013 and 2023. From an initial return of 1430 records, 22 studies met the inclusion criteria and were synthesized based on the neuroimaging modality. There is converging evidence that auditory-motor synchronization engages bilateral cortical and subcortical networks, including the supplementary motor area, premotor cortex, ventrolateral prefrontal cortex, basal ganglia, and cerebellum. Specifically, the supplementary motor area and the basal ganglia are essential for beat-based timing and internally guided rhythmic movements, while the cerebellum plays an important role in tracking and processing complex rhythmic patterns and synchronizing to the external beat. Self-paced tapping is associated with additional activations in the prefrontal cortex and the basal ganglia, suggesting that tapping in the absence of auditory cues requires more neural resources. Lastly, existing studies indicate that movement rate and the type of music further modulate the EEG power in the alpha and beta frequency bands. These findings are discussed in the context of clinical implications and rhythm-based therapies.

The effect of early postnatal auditory stimulation on outcomes in preterm infants.

Preterm infants are deprived of in utero sensory stimulation during the third trimester, an important period of central nervous system development. As a result, maturational trajectories are often reduced in infants born preterm. One such system affected is the brain including the auditory and respiratory control pathways. During normal pregnancy the intrauterine environment attenuates external auditory stimuli while exposing the fetus to filtered maternal voice, intra-abdominal sounds, and external stimuli. In contrast, during the third trimester of development, preterm infants are exposed to a vastly different soundscape including non-attenuated auditory sounds and a lack of womb related stimuli, both of which may affect postnatal brain maturation. Therefore, fostering a nurturing postnatal auditory environment during hospitalization may have a significant impact on related outcomes of preterm infants. Studies using a range of postnatal auditory stimulations have suggested that exposure to sounds or lack thereof can have a significant impact on outcomes. However, studies are inconsistent with sound levels, duration of exposure to auditory stimuli, and the gestational age at which infants are exposed. IMPACT: Auditory stimulation can provide a low cost and low risk intervention to stabilize respiration, improve neuronal maturation and reduce long-term sequelae in preterm infants. The potential benefits of auditory stimulation are dependent on the type of sound, the duration of exposure and age at time of exposure. Future studies should focus on the optimal type and duration of sound exposure and postnatal developmental window to improve outcomes.

Comparison of oral versus intranasal methylcobalamin in patients of tinnitus

Background: Tinnitus is perception of sound in the absence of an external auditory stimulus. It is an experience that originates from a cause or trigger in the cochlea, brainstem or at higher centres. Methods: A randomized, double-blinded pilot study was conducted, wherein a total of 64 patients were enrolled. Of which 32 were considered as Group A (oral methylcobalamin was administered) and 32 in Group B (intranasal methylcobalamin was administered). Group A patients enrolled randomly received oral methylcobalamin therapy (tablet methylcobalamin 500 mcg tablet once a day for a period of 6 weeks). Group B patients enrolled randomly received intranasal methylcobalamin treatment (nasal spray 500 mcg per day) for a period of 6 weeks. Results: A sum of 19 patients of the total patients included in the study were found to be Vitamin B12 deficient that is 42.1% were considered to be Vitamin B12 deficient when the normal levels were considered to be 250 pg/ml, which could be considered to be a significantly high prevalence. Patients having Vitamin B12 deficiency showed improvement in visual analogue scale score after vitamin B12 therapy. Conclusions: Supplementation of Vitamin B12 in vitamin B12 deficient patients having tinnitus has shown symptomatic improvement. However, no significant improvement in visual analogue scale scores in patients without B12 deficiency was observed. There was improvement in VAS in cobalamin-deficient patients receiving Vitamin B12 weekly for 6 weeks.

The Role of Attention Modulation and Its Neurophysiological Mechanisms in Tinnitus Management: A Review

Background and Aim: Tinnitus, characterized by the perception of sound without the presence of an external auditory stimulus, can profoundly affect the quality of life. This review study aims to assess the role of attention modulation in tinnitus management and investigate the neurophysiological mechanism of attention and its interaction with emotional processing in patients with tinnitus. Recent Findings: The studies revealed differences in the function of attentional networks among individuals with tinnitus. The studies showed the positive impact of various techniques for attention modulation through direct attention training or indirect mechanisms influencing attention. These techniques could modify attentional biases, enhance attention control, and alleviate tinnitus-related distress. Conclusion: The results of studies suggest the potential role of attention modulation in tinnitus management. By targeting attentional processes, researchers and clinicians can provide more effective interventions for individuals with tinnitus. However, there is a need for further investigation to optimize the intervention protocols by collaboration between researchers, clinicians, and individuals with tinnitus to achieve success in tinnitus management. Background and Aim: Tinnitus, characterized by the perception of sound without the presence of an external auditory stimulus, can profoundly affect the quality of life. This review study aims to assess the role of attention modulation in tinnitus management and investigate the neurophysiological mechanism of attention and its interaction with emotional processing in patients with tinnitus. Recent Findings: The studies revealed differences in the function of attentional networks among individuals with tinnitus. The studies showed the positive impact of various techniques for attention modulation through direct attention training or indirect mechanisms influencing attention. These techniques could modify attentional biases, enhance attention control, and alleviate tinnitus-related distress. Conclusion: The results of studies suggest the potential role of attention modulation in tinnitus management. By targeting attentional processes, researchers and clinicians can provide more effective interventions for individuals with tinnitus. However, there is a need for further investigation to optimize the intervention protocols by collaboration between researchers, clinicians, and individuals with tinnitus to achieve success in tinnitus management. Keywords: Tinnitus; attention; tinnitus management; neurophysiological mechanism; attention training

An Examination of Tinnitus from Both Clinical and Epidemiological Perspectives: A Comprehensive Review Study

Tinnitus refers to the subjective perception of sounds in the brain or ears, such as buzzing, clicking, or hissing, in the absence of any external auditory stimuli. It is a commonly encountered phenomenon among individuals worldwide. The primary aim of this study was to examine recent advancements in the literature concerning the frequency, origins, control, and therapy of the subject in question. The researchers utilized prominent research engines such as Google, Google Scholar, Science Direct, and others to gather publications about tinnitus. The findings indicated that tinnitus is widely prevalent on a global scale and can be ascribed to neurological, hereditary, and environmental reasons. The therapy and therapeutic options for this condition are diverse and depend on the underlying causes.

Investigation of cyclist’s distraction due to external auditory and visual stimuli

Investigation of cyclist’s distraction due to external auditory and visual stimuli

Drug-induced musical hallucination.

Musical hallucination is a rare perceptual phenomenon wherein individuals hear music in the absence of external auditory stimuli. This phenomenon occurs across diverse medical conditions and can be triggered by some drugs. The underlying mechanism of drug-induced hallucination is unknown. This study explores drug-induced musical hallucination through a literature review, aiming to investigate its pathophysiology and potential treatment modalities. A literature search was conducted until January 2024 using databases PubMed, WorldCat, Google Scholar, and DOAJ, with keywords "drugs induced musical hallucination" or "drugs" combined with "musical hallucination." The search yielded 24 articles which met inclusion criteria, encompassing 27 cases. The average patient age was 58.3years, with 67.9% females. Prevalent conditions among cases included hearing impairments, psychiatric disorders, cancers, and neurodegenerative conditions. Common trigger drugs comprised antidepressants, opioids, anti-Parkinson drugs, ketamine, and voriconazole. Musical hallucination descriptions varied widely, and 6 patients reported concurrent visual hallucinations. The onset of symptoms ranged from 75min to 240days. Treatment strategies included termination of trigger drugs, dosage reduction, alteration of administration routes or formula, switching to similar drugs, or addition of antidepressants, sedatives, or atypical antipsychotic medications. Musical hallucinations completely disappeared in 24/27 (88.9%) patients but continued in 3/27 (11.1%) patients. The current study concludes that drug-induced musical hallucination may arise from altering neurotransmitter/receptor balance and intricate interactions between trigger drugs and underlying conditions.

Reduced neural connectivity in the caudate anterior head predicts hallucination severity in schizophrenia.

Caudate functional abnormalities have been identified as one critical neural substrate underlying sensory gating impairments that lead to auditory phantom hallucinations in both patients with schizophrenia (SZ) and tinnitus, characterized by the perception of internally generated sounds in the absence of external environmental auditory stimuli. In this study, we tested the hypothesis as to whether functional connectivity abnormalities in distinct caudate subdivisions implicated in sensory gating and auditory phantom percepts in tinnitus, which are currently being localized for neuromodulation targeting using deep brain stimulation techniques, would be associated with auditory phantom hallucination severity in SZ. Twenty five SZ and twenty eight demographically-matched healthy control (HC) participants, completed this fMRI resting-state study and clinical assessments. Between-group seed-to-voxel analyses revealed only one region, the caudate anterior head, which showed reduced functional connectivity with the thalamus that survived whole-brain multiple comparison corrections. Importantly, connectivity between the caudate anterior head with thalamus negatively correlated with hallucination severity. In the present study, we deliver the first evidence of caudate subdivision specificity for the neural pathophysiology underlying hallucinations in schizophrenia within a sensory gating framework that has been developed for auditory phantoms in patients with tinnitus. Our findings provide transdiagnostic convergent evidence for the role of the caudate in the gating of auditory phantom hallucinations, observed across patients with SZ and tinnitus by specifying the anterior caudate division is key to mediation of hallucinations, and creating a path towards personalized treatment approaches to arrest auditory phantom hallucinations from reaching perceptual awareness.

Targeting the Limbic System: Insights into Its Involvement in Tinnitus.

Tinnitus is originally derived from the Latin verb tinnire, which means "to ring". Tinnitus, a complex disorder, is a result of sentient cognizance of a sound in the absence of an external auditory stimulus. It is reported in children, adults, and older populations. Patients suffering from tinnitus often present with hearing loss, anxiety, depression, and sleep disruption in addition to a hissing and ringing in the ear. Surgical interventions and many other forms of treatment have been only partially effective due to heterogeneity in tinnitus patients and a lack of understanding of the mechanisms of tinnitus. Although researchers across the globe have made significant progress in understanding the underlying mechanisms of tinnitus over the past few decades, tinnitus is still deemed to be a scientific enigma. This review summarises the role of the limbic system in tinnitus development and provides insight into the development of potential target-specific tinnitus therapies.

Equine Behavioural and Physiological Responses to Auditory Stimuli in the Presence and Absence of Noise-Damping Ear Covers.

Despite numerous studies investigating responses to visual perception, there is limited research into how horses respond to different auditory stimuli. Although 'noise-damping' ear covers are frequently used on sport horses to minimise distraction from external auditory stimuli, the effectiveness of ear covers has not been established. This study aimed to (i) investigate the responses of horses to different sounds commonly present in a competition environment, and (ii) compare these responses in the presence and absence of ear covers. A total of 18 horses were presented with 5 sounds commonly heard in competition or stable environments both with and without ear covers, in a randomised order crossover design. Behavioural and heart rate responses were recorded. Responses were compared between sounds and with/without ear covers. Differences in physiological and behavioural responses to different complex auditory stimuli were shown. An overall difference in physiological and behavioural responses with and without ear covers was detected, although the only difference in heart rate between ear covers and no ear covers that individually achieved significance was the feed sound. These findings suggest that horses can discriminate sounds and alter their responses based on the individual stimulus, and these responses are reduced when wearing ear covers with varying effectiveness for different sounds.

A very musical psychopathology – from intrusive musical imagery, to musical obsessions and hallucinations

IntroductionThe semiological spectrum that encompasses musical imagery is a very confusing field, as it is often difficult to understand the nature of the underlying psychopathological phenomenon from the patient’s description.ObjectivesThe purpose of the authors is to explore reviewing, distinguishing and organizing the concepts such as Intrusive musical imagery, musical obsessions, musical hallucinations, pseudohallucinations and musical palinacousis.MethodsA brief non-systematized review is presented, using the literature available on PubMed and Google Scholar.ResultsIntrusive musical imagery (earworms, ohrwurms, or involuntary musical imagery) occur in more than 85% of general population, without pathology or ear disease. It involves the involuntary repetition of 15-30 seconds of a fragment of music/tune, persisting like a looping soundtrack, not being aversive.Musical obsessions are a rare form of intrusive imagery, occurring either with other symptoms of Obsessive Compulsive Disorder or isolated (“The stuck song syndrome”). It is recurrent, persistent, intrusive, unintentional, time consuming and causes distress or functional impairment (although not as ego-dystonic and aversive as usually intrusive visual imagery are); preserved insight.Musical hallucinations occur only in 0,16% in a general hospital; they can be linked to psychiatric diseases, but they are more common in neurological diseases (cerebral lesions, Parkinson’s disease, delirium, drug induced…). They are reported to with less controllability, less lyrical content, and lower familiarity, than other forms of inner music; are perceived to arise from an external source and are interpreted as veridical.Musical Pseudohallucinations can arise after severe hearing loss, in hallucinogen intoxication and in psychotic or non-psychotic disorders (as dissociative states or in borderline personality disorder). They occur in inner/subjective space, but insight can fluctuate.Musical palinacousis is associated with electroencephalogram and neuroimaging abnormalities, linked to structural brain pathology. There is perseveration (echoing) of an external auditory stimulus occurs after cessation of the stimulus.ConclusionsA rash classification can lead to misdiagnosis (for e.g. interpreting obsessive symptoms as hallucinatory phenomena or rendering an organic pathology undiagnosed) and the institution of inappropriate therapy. It is important to carefully explore these musical imagery phenomena when patients present these complaints, taking some time to characterize them.Disclosure of InterestNone Declared

The experiences of patients with tinnitus: a qualitative study

Purpose: Tinnitus, which is often described as the conscious awareness of a sound without an external auditory stimulus, is one of the most common symptoms in the general population. This study aimed to explore the experiences of individuals living with tinnitus.Methods: In this qualitative exploratory study, data were collected from November 2017 to January 2018 through in-depth individual interviews with 11 tinnitus patients. Verbatim transcripts and field notes were analyzed using content analysis.Results: The extracted content was classified into three core categories of tinnitus experiences: “suffering from constant sound,” “being imprisoned surrounded by persistent noise,” and “efforts to overcome.”Conclusion: This study shows that tinnitus had a severe negative impact on patients’ lives. The finding will help healthcare providers understand their patients more deeply.

Rhythmic tapping difficulties in adults who stutter: A deficit in beat perception, motor execution, or sensorimotor integration?

The study aims to better understand the rhythmic abilities of people who stutter and to identify which processes potentially are impaired in this population: (1) beat perception and reproduction; (2) the execution of movements, in particular their initiation; (3) sensorimotor integration. Finger tapping behavior of 16 adults who stutter (PWS) was compared with that of 16 matching controls (PNS) in five rhythmic tasks of various complexity: three synchronization tasks - a simple 1:1 isochronous pattern, a complex non-isochronous pattern, and a 4 tap:1 beat isochronous pattern -, a reaction task to an aperiodic and unpredictable pattern, and a reproduction task of an isochronous pattern after passively listening. PWS were able to reproduce an isochronous pattern on their own, without external auditory stimuli, with similar accuracy as PNS, but with increased variability. This group difference in variability was observed immediately after passive listening, without prior motor engagement, and was not enhanced or reduced after several seconds of tapping. Although PWS showed increased tapping variability in the reproduction task as well as in synchronization tasks, this timing variability did not correlate significantly with the variability in reaction times or tapping force. Compared to PNS, PWS exhibited larger negative mean asynchronies, and increased synchronization variability in synchronization tasks. These group differences were not affected by beat hierarchy (i.e., "strong" vs. "weak" beats), pattern complexity (non-isochronous vs. isochronous) or presence versus absence of external auditory stimulus (1:1 vs. 1:4 isochronous pattern). Differences between PWS and PNS were not enhanced or reduced with sensorimotor learning, over the first taps of a synchronization task. Our observations support the hypothesis of a deficit in neuronal oscillators coupling in production, but not in perception, of rhythmic patterns, and a larger delay in multi-modal feedback processing for PWS.

The development of a home-based technology to improve gait in people with Parkinson's disease: a feasibility study

BackgroundPeople with Parkinson’s disease (PwP) may experience gait impairment and freezing of gait (FOG), a major cause of falls. External cueing, including visual (e.g., spaced lines on the floor) and auditory (e.g., rhythmic metronome beats) stimuli, are considered effective in alleviating mobility deficits and FOG. Currently, there is a need for a technology that delivers automatic, individually adjusted cues in the homes of PwP. The aims of this feasibility study were to describe the first step toward the development of a home-based technology that delivers external cues, test its effect on gait, and assess user experience.MethodsIterative system development was performed by our multidisciplinary team. The system was designed to deliver visual and auditory cues: light stripes projected on the floor and metronome beats, separately. Initial testing was performed using the feedback of five healthy elderly individuals on the cues’ clarity (clear visibility of the light stripes and the sound of metronome beats) and discomfort experienced. A pilot study was subsequently conducted in the homes of 15 PwP with daily FOG. We measured participants' walking under three conditions: baseline (with no cues), walking with light stripes, and walking to metronome beats. Outcome measures included step length and step time. User experience was also captured in semi-structured interviews.ResultsRepeated-measures ANOVA of gait assessment in PwP revealed that light stripes significantly improved step length (p = 0.009) and step time (p = 0.019) of PwP. No significant changes were measured in the metronome condition. PwP reported that both cueing modalities improved their gait, confidence, and stability. Most PwP did not report any discomfort in either modality and expressed a desire to have such a technology in their homes. The metronome was preferred by the majority of participants.ConclusionsThis feasibility study demonstrated the usability and potential effect of a novel cueing technology on gait, and represents an important first step toward the development of a technology aimed to prevent FOG by delivering individually adjusted cues automatically. A further full-scale study is needed.Trial registration This study was registered in ClinicalTrials.gov at 1/2/2022 NCT05211687.

The Effect of External Dissociative Stimuli on Plank Duration Performed by Male Collegiate Soccer Players.

D'Agata, MN, Staub, JP, Scavone, DJ, and Kane, GM. The effect of external dissociative stimuli on plank duration performed by male collegiate soccer players. J Strength Cond Res 37(5): e341-e345, 2023-Individuals commonly use music as an external auditory stimulus to divert their attention away from aerobic endurance exercise tasks. Music generally results in lower ratings of perceived exertion, which may be the mechanism by which it increases aerobic exercise task duration. However, less is known regarding how music affects the performance of other forms of exercise, such as isometric exercise. Moreover, the effects of different external stimuli on isometric task duration, such as the use of virtual reality (VR), have yet to be investigated. Therefore, the purpose of this study was to investigate the effects of self-selected music (SSM) and VR on isometric exercise task duration using a forearm plank. We hypothesized that both SSM and VR would effectively increase plank duration compared with no external stimuli. Seventeen male collegiate soccer players (19 ± 1 year) completed 3 planks to failure on 3 separate days, with 48-72 hours between the trials. The ordering of each exercise condition (SSM, VR, or None) was randomized for a total of 6 potential orders. A one-way repeated-measures analysis of variance was used to evaluate differences in plank duration and average heart rate (HR avg ) between each trial, and significance was set at p < 0.05. There were no differences in plank duration (SSM: 200 ± 44, VR: 173 ± 38, None: 177 ± 37 seconds) or HR avg (SSM: 96 ± 18, VR: 92 ± 21, None: 87 ± 18 beats per minute) between the conditions. We conclude that there was no effect of external stimuli (SSM or VR) on isometric exercise task duration and the use of these modalities should be based on exerciser preference.

Comparing the Efficacy of Amitriptyline and Melatonin on Tinnitus Treatment

Background: Tinnitus is described as the perception of sounds occurring in one or both ears or inside the human head without external auditory stimuli. Objectives: This study aimed to compare the efficacy of amitriptyline and melatonin in the treatment of tinnitus. Methods: This study was a randomized double-blind clinical trial of 60 patients referred to the neurology clinics of Kashani and Al-Zahra hospitals in Isfahan, Iran in 2020. Each patient was randomly assigned 1 code. Patients first filled in the tinnitus handicap inventory (THI) and visual analogue scales (VAS) questionnaires and were given either one of the two drugs (melatonin and amitriptyline) for 6 weeks. After collecting the desired information using an independent t test and paired t test in SPSS 26 software and error level of 0.05 the results were analyzed. Results: Thirty patients were in the amitriptyline group and 30 patients were in the melatonin group, of which 25 were men (41.7%) and 35 were women (58.3%) with a minimum age of 18 years and a maximum of 65 years. There was no significant difference between the reduction of tinnitus before and after taking the drugs based on VAS scale in amitriptyline and melatonin groups (P=0.234), however there was a significant difference between the effect of two amitriptyline and melatonin drugs on the reduction of tinnitus based on the THI questionnaire (P=0.018). Conclusion: The rate of tinnitus in patients decreased for 6 weeks with the use of amitriptyline and melatonin, but amitriptyline had a better effect on reducing the complications and pain of tinnitus.

A Wireless System for EEG Acquisition and Processing in an Earbud Form Factor with 600 Hours Battery Lifetime.

In recent years, in-ear electroencephalography (EEG) was demonstrated to record signals of similar quality compared to standard scalp-based EEG, and clinical applications of objective hearing threshold estimations have been reported. Existing devices, however, still lack important features. In fact, most of the available solutions are based on wet electrodes, require to be connected to external acquisition platforms, or do not offer on-board processing capabilities. Here we overcome all these limitations, presenting an ear-EEG system based on dry electrodes that includes all the acquisition, processing, and connectivity electronics directly in the ear bud. The earpiece is equipped with an ultra-low power analog front-end for analog-to-digital conversion, a low-power MEMS microphone, a low-power inertial measurement unit, and an ARM Cortex-M4 based microcontroller enabling on-board processing and Bluetooth Low Energy connectivity. The system can stream raw EEG data or perform data processing directly in-ear. We test the device by analysing its capability to detect brain response to external auditory stimuli, achieving 4 and 1.3 mW power consumption for data streaming or on board processing, respectively. The latter allows for 600 hours operation on a PR44 zinc-air battery. To the best of our knowledge, this is the first wireless and fully self-contained ear-EEG system performing on-board processing, all embedded in a single earbud. Clinical relevance- The proposed ear-EEG system can be employed for diagnostic tasks such as objective hearing threshold estimations, outside of clinical settings, thereby enabling it as a point-of-care solution. The long battery lifetime is also suitable for a continuous monitoring scenario.

Children with amblyaudia show less flexibility in auditory cortical entrainment to periodic non-speech sounds

Objective We investigated auditory temporal processing in children with amblyaudia (AMB), a subtype of auditory processing disorder (APD), via cortical neural entrainment. Design and study samples Evoked responses were recorded to click-trains at slow vs. fast (8.5 vs. 14.9/s) rates in n = 14 children with AMB and n = 11 age-matched controls. Source and time–frequency analyses (TFA) decomposed EEGs into oscillations (reflecting neural entrainment) stemming from bilateral auditory cortex. Results Phase-locking strength in AMB depended critically on the speed of auditory stimuli. In contrast to age-matched peers, AMB responses were largely insensitive to rate manipulations. This rate resistance occurred regardless of the ear of presentation and in both cortical hemispheres. Conclusions Children with AMB show less rate-related changes in auditory cortical entrainment. In addition to reduced capacity to integrate information between the ears, we identify more rigid tagging of external auditory stimuli. Our neurophysiological findings may account for domain-general temporal processing deficits commonly observed in AMB and related APDs behaviourally. More broadly, our findings may inform communication strategies and future rehabilitation programmes; increasing the rate of stimuli above a normal (slow) speech rate is likely to make stimulus processing more challenging for individuals with AMB/APD.

Listening to White Noise Improved Verbal Working Memory in Children with Attention-Deficit/Hyperactivity Disorder: A Pilot Study.

Existing research demonstrates that children with attention-deficit/hyperactivity disorder (ADHD) underperform in cognitive tasks involving working memory (WM) due to hypo-arousal, which has led to the development of arousal regulation models to determine proper levels of arousal and optimal cognitive outcomes. The present study focuses on investigating the effects of external auditory stimuli on verbal WM in children with ADHD. Thirteen children with ADHD (aged 6–10 years old) and thirteen age- and gender-matched children with typical development (TD) completed the verbal WM task when listening to no sound, white noise, or pleasant music. A two-way repeated-measures analysis of variance was used to compare the verbal WM performance between groups in the three auditory conditions. Children with ADHD showed the best verbal WM performance when listening to white noise and the worst performance when listening to no sound. Yet, children with TD performed the best in the no-sound condition and the worst in the white noise condition. Our findings suggest auditory white noise is beneficial for ideal arousal regulation and cognitive performance involving verbal WM for children with ADHD and support the moderate brain arousal model. Providing external white noise is a non-invasive and cost-effective approach to improving verbal WM in children with ADHD in real-world contexts.

Children with amblyaudia show less flexibility in auditory cortical entrainment to periodic non-speech sounds

We investigated auditory temporal processing in children with amblyaudia (AMB), a subtype of auditory processing disorder, via cortical neural entrainment. Evoked responses were recorded to click-trains at slow versus fast (8.5 versus 14.9/sec) rates in n = 14 children with AMB and n = 11 age-matched controls. Source and time-frequency analyses decomposed EEGs into oscillations (reflecting neural entrainment) stemming from the bilateral auditory cortex. Phase-locking strength in AMB depended critically on the speed of auditory stimuli. In contrast to age-matched peers, AMB responses were largely insensitive to rate manipulations. This rate resistance was seen regardless of the ear of presentation and in both cortical hemispheres. Children with AMB show a stark inflexibility in auditory cortical entrainment to rapid sounds. In addition to reduced capacity to integrate information between the ears, we identify a new functional characterization of AMB in the form of more rigid tagging of external auditory stimuli. Our neurophysiological findings may account for certain temporal processing deficits commonly observed in AMB and related auditory processing disorders (APDs) behaviorally. More broadly, our findings may inform communication strategies and future rehabilitation programs; increasing the rate of stimuli above a normal (slow) speech rate is likely to make stimulus processing more challenging for individuals with AMB/APD.