Auditory Event-related Potentials Research Articles

A study of cognitive functions in elderly men from the Arctic region of the Russian Federation with arterial hypertension using the auditory event-related potentials P300

AIM: To study the effect of arterial hypertension on cognitive functions by evaluating the auditory event-related potentials (ERP) Р300 in men aged 60–74 years from the Arctic region of the Russian Federation with the special emphasis on men receiving antihypertensive therapy with controlled arterial hypertension and those who either do not take antihypertensive drugs or take them both regularly and irregularly without controlling blood pressure. MATERIAL AND METHODS: The study included 64 men with arterial hypertension and 19 men without hypertension (n=19) in Arkhangelsk. Registration of the Р300 and N2 components was performed using the Neuron-Spektr-4/VPM electroencephalograph (Neurosoft, Russia), utilizing the oddball paradigm. Blood pressure (BP) was measured with an automatic tonometer AD Medical UA-668 (Japan). RESULTS: In men without arterial hypertension and in those with controlled arterial hypertension, where the median values of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were within normal ranges, there were no differences in the latency (LT) of N2 and P300, nor in the magnitude of the P300 amplitude between these groups. In contrast, men who do not take antihypertensive drugs or receive antihypertensive therapy both regularly and irregularly without controlling their blood pressure, and who have SBP and DBP above normal values, showed an elongation of LT N2 in the parietal (P3), central (C3), and middle temporal (T3) sections on the left, and in the frontal section on the right (F4). There was also an elongation of LT P300 in the middle temporal region on the right (T4) and frontal regions on the right (F4), along with a decrease in the median values of the P300 amplitude in the anterior-temporal (F8, F7) parts of the brain. This indicates a deficit in attention, an increase in the time required for primary recognition and differentiation of signals, and a reduction in the speed of information processing and decision-making. CONCLUSION: In older men, SBP above 140 mmHg and DBP above 90 mmHg are associated with cognitive impairment as determined by the auditory event-related potentials P300.

Using the Cocktail Party Effect to Add the Coding Dimension of Auditory Event Related Potential Brain-Computer Interface.

The auditory event-related potential based brain-computer interface (aERP-BCI) is a classical paradigm of brain-computer communication. To improve the coding efficiency of aERP-BCI, this study proposes a method using two parallel voice channels to add the coding dimension based on the cocktail party effect. The novel paradigm used male and female voices to establish two parallel oddball sound stimulus sequences. In comparison, the baseline paradigm only presented male or female stimulus sequences. Both the double voice condition (DVC) and the single voice condition (SVC) paradigms carried out offline experiments and the DVC also carried out online experiment. Subsequently, the EEG signal and BCI operation results were compared and analyzed. The cocktail party effect caused a significant difference in the EEG responses of non-target stimulus between the focused vocal channel and the ignored vocal channel under the DVC paradigm, and the focused and ignored channels achieved a recognition accuracy of 97.2%. The target recognition rate of DVC was 82.3%, with no significant difference compared with 85% of SVC while the information transfer rate (ITR) of DVC reaching 15.3 bits/min was significantly higher than that of SVC. The cocktail party effect improves the coding efficiency by adding parallel channels without reducing the target/non-target stimulus recognition in the focused vocal channel. This provides a novel direction for the performance improvement of aERP-BCI.

Interaction of spatial attention and the associated reward value of audiovisual objects

Reward value and selective attention both enhance the representation of sensory stimuli at the earliest stages of processing. It is still debated whether and how reward-driven and attentional mechanisms interact to influence perception. Here we ask whether the interaction between reward value and selective attention depends on the sensory modality through which the reward information is conveyed. Human participants first learned the reward value of uni-modal visual and auditory stimuli during a conditioning phase. Subsequently, they performed a target detection task on bimodal stimuli containing a previously rewarded stimulus in one, both, or neither of the modalities. Additionally, participants were required to focus their attention on one side and only report targets on the attended side. Our results showed a strong modulation of visual and auditory event-related potentials (ERPs) by spatial attention. We found no main effect of reward value but importantly we found an interaction effect as the strength of attentional modulation of the ERPs was significantly affected by the reward value. When reward effects were examined separately with respect to each modality, auditory value-driven modulation of attention was found to dominate the ERP effects whereas visual reward value on its own led to no effect, likely due to its interference with the target processing. These results inspire a two-stage model where first the salience of a high reward stimulus is enhanced on a local priority map specific to each sensory modality, and at a second stage reward value and top-down attentional mechanisms are integrated across sensory modalities to affect perception.

The P300 component of the auditory event-related potential in adult psychiatric and neurologic disorders: a narrative review of clinical and experimental evidence.

The auditory P300 wave, also known as P3b, is an event-related potential component thought to reflect central information processes involved in stimulus evaluation or categorization. It is typically elicited using the oddball paradigm, which involves mixing low-probability target items with high-probability standard stimuli. Its latency is associated with the timing of cognitive processes such as stimulus evaluation and response preparation, while its amplitude is related to the amount of attentional resources engaged during the task. Despite decades of use in research settings, its application in clinical practice has been limited. Prolongation of latencies and reduction of amplitudes in the auditory P3b have been observed in both psychiatric and neurological conditions. This includes cases where traditional neuropsychological tests are challenging due to severe motor or speech dysfunctions, or in conditions characterized by subtle cognitive deficits. Additionally, specific laterality patterns in psychoses and a loss of P300 habituation in migraines have been described. The wealth of experimental evidence supports the use of this evoked potential, which can be elicited through a relatively simple paradigm, for objectively evaluating cognition in psychiatric and neurological patients, particularly in follow-up assessments. Therefore, the auditory P300 appears to be a valuable tool for monitoring the clinical course of patients with mental and neurological disorders in certain circumstances.

Cognition in Patients with Spinocerebellar Ataxia 1 (SCA1) and 2 (SCA2): A Neurophysiological and Neuropsychological Approach.

Background/Objectives: Cognitive impairment in spinocerebellar ataxia patients has been reported since the early-disease stage. We aimed to assess cognitive differences in SCA1 and SCA2 patients. Methods: We performed neuropsychological (NPS) and neurophysiological (auditory event-related potentials, aERPs) assessments in 16 SCA1 and 18 SCA2 consecutive patients. Furthermore, clinical information (age at onset, disease duration, motor disability) was collected. Results: NPS tests yielded scores in the normal range in both groups but with lower scores in the Frontal Assessment Battery (p < 0.05) and Visual Analogue Test for Anosognosia for motor impairment (p < 0.05) in SCA1, and the Trail Making Test (p < 0.01), Raven's progressive matrices (p < 0.01), Stroop (p < 0.05), and emotion attribution tests (p < 0.05) in SCA2. aERPs showed lower N100 amplitude (p < 0.01) and prolonged N200 latency (p < 0.01) in SCA1 compared with SCA2. Clinically, SCA2 had more severe motor disability than SCA1 in the Assessment and Rating of Ataxia Scale. Conclusions: SCA2 showed more significant difficulties in attentional, visuospatial, and emotional function, and greater motor impairment. In contrast, SCA1 showed less cognitive flexibility/phasic ability, probably affected by a more severe degree of dysarthria. The same group revealed less neural activity during nonconscious attentional processing (N100-N200 data), suggesting greater involvement of sensory pathways in discriminating auditory stimuli. NFS did not correlate with NPS findings, implying an independent relationship. However, the specific role of the cerebellum and cerebellar symptoms in NPS test results deserves more focus.

Developmental trajectory and sex differences in auditory processing in a PTEN-deletion model of autism spectrum disorders

Autism Spectrum Disorders (ASD) encompass a wide array of debilitating symptoms, including severe sensory deficits and abnormal language development. Sensory deficits early in development may lead to broader symptomatology in adolescents and adults. The mechanistic links between ASD risk genes, sensory processing and language impairment are unclear. There is also a sex bias in ASD diagnosis and symptomatology. The current study aims to identify the developmental trajectory and genotype- and sex-dependent differences in auditory sensitivity and temporal processing in a Pten-deletion (phosphatase and tensin homolog missing on chromosome 10) mouse model of ASD. Auditory temporal processing is crucial for speech recognition and language development and deficits will cause language impairments. However, very little is known about the development of temporal processing in ASD animal models, and if there are sex differences. To address this major gap, we recorded epidural electroencephalography (EEG) signals from the frontal (FC) and auditory (AC) cortex in developing and adult Nse-cre PTEN mice, in which Pten is deleted in specific cortical layers (layers III-V) (PTEN conditional knock-out (cKO). We quantified resting EEG spectral power distribution, auditory event related potentials (ERP) and temporal processing from awake and freely moving male and female mice. Temporal processing is measured using a gap-in-noise-ASSR (auditory steady state response) stimulus paradigm. The experimental manipulation of gap duration and modulation depth allows us to measure cortical entrainment to rapid gaps in sounds. Temporal processing was quantified using inter-trial phase clustering (ITPC) values that account for phase consistency across trials. The results show genotype differences in resting power distribution in PTEN cKO mice throughout development. Male and female cKO mice have significantly increased beta power but decreased high frequency oscillations in the AC and FC. Both male and female PTEN cKO mice show diminished ITPC in their gap-ASSR responses in the AC and FC compared to control mice. Overall, deficits become more prominent in adult (p60) mice, with cKO mice having significantly increased sound evoked power and decreased ITPC compared to controls. While both male and female cKO mice demonstrated severe temporal processing deficits across development, female cKO mice showed increased hypersensitivity compared to males, reflected as increased N1 and P2 amplitudes. These data identify a number of novel sensory processing deficits in a PTEN-ASD mouse model that are present from an early age. Abnormal temporal processing and hypersensitive responses may contribute to abnormal development of language function in ASD.

Effects of daily listening to 6 Hz binaural beats over one month: an event-related potentials study

The aim of the present study was to identify cognitive alterations, as indicated by event-related potentials (ERPs), after one month of daily exposure to theta binaural beats (BBs) for 10 minutes. The recruited healthy subjects (n = 60) were equally divided into experimental and control groups. For a month, the experimental group was required to practice BBs listening daily, while the control group did not. ERPs were assessed at three separate visits over a span of one month, with a two-week interval between each visit. At each visit, ERPs were measured before and after listening. The auditory and visual ERPs significantly increased the auditory and visual P300 amplitudes consistently at each visit. BBs enhanced the auditory N200 amplitude consistently across all visits, but the visual N200 amplitude increased only at the second and third visits. Compared to the healthy controls, daily exposure to BBs for two weeks resulted in increased auditory P300 amplitude. Additionally, four weeks of BBs exposure not only increased auditory P300 amplitude but also reduced P300 latency. These preliminary findings suggest that listening to BBs at 6 Hz for 10 minutes daily may enhance certain aspects of cognitive function. However, further research is needed to confirm these effects and to understand the underlying mechanisms. Identifying the optimal duration and practice of listening to 6 Hz BBs could potentially contribute to cognitive enhancement strategies in healthy individuals.

Corollary discharge and anomalous self-experiences in schizophrenia and bipolar disorder: A specificity analysis

ObjectiveThe Corollary Discharge (CD) mechanism inhibits self-generated speech sound perception, appearing disrupted in schizophrenia and potentially contributing to Anomalous Self-Experiences (ASEs). However, it remains unclear if this alteration and its correlation with ASEs extend to other psychotic disorders. MethodsElectroencephalography was used to study the N1 Event-Related Potential (ERP) as an index of CD-mediated suppression in the auditory cortex across thirty-five participants with schizophrenia, twenty-six with bipolar disorder, and thirty healthy controls. Auditory N1 was elicited by two conditions: real-time listening to self-pronounced vowels while speaking through connected microphone and earphones (listen/talk −or talk condition in previous literature-) and passive listening to the same previously recorded self-uttered vowels (listen/no talk −or listen condition-). ResultsN1 ERP amplitude was lower in the listen/talk condition compared to listen/no talk across all groups. However, N1 suppression was significantly reduced in schizophrenia, with bipolar patients showing intermediate attenuation between both groups (i.e., non-significantly different from controls). Furthermore, N1 suppression inversely correlated with ASEs severity only in schizophrenia. ConclusionsDysfunction of the CD mechanism may be a defining feature of schizophrenia, where it is connected to ASEs. SignificanceThese results corroborate previous findings linking auditory N1 ERP suppression with disrupted CD mechanism in schizophrenia, but not in bipolar disorder.

Early auditory processing of speech in prelingually-deafened children with cochlear implants based on event-related potentials

Objective: To investigate the early auditory discrimination of vowels, consonants and lexical tones in prelingually-deafened children with cochlear implants (CI) using auditory event-related potentials. Methods: Nineteen prelingually-deafened CI children and 19 normal hearing (NH) children were recruited in this study. A multi-deviant oddball paradigm was constructed using the monosyllable/ta1/as the standard stimulus and monosyllables/tu1/,/te1/, /da1/,/ra1/,/ta4/and/ta2/as the deviant stimuli. The event-related potentials evoked by vowel, consonant and lexical tone contrasts were recorded and analyzed in the two groups. Results: NH children showed robust mismatch negativities (MMNs) to vowel, consonant and lexical tone contrasts (P<0.05), whereas CI children only showed positive mismatch responses (pMMRs) and P3a responses to the vowel (P<0.05) and consonant contrasts (P<0.05) and no significant event-related potential to the lexical tone contrasts (P>0.05). The longer pMMR and P3a peak latencies (P<0.01) but similar amplitudes (P>0.05) were found in CI children than in NH children. CI children showed weaker phase synchronization of θ oscillations than NH children (P<0.05). The duration of CI use was positively correlated with the scores of Categories of Auditory Performance (CAP) (P=0.004), Speech Intelligibility Rate (SIR) (P=0.044) and Meaningful Auditory Integration Scale (MAIS) (P=0.001) in CI children. Conclusions: Prelingually-deafened CI children can process vowels and consonants at an early stage. However, their ability of processing speech, especially lexical tones, is still more immature compared with their NH peers. The event-related potentials could be objective electrophysiological indicators reflecting the maturity of CI children's auditory speech functions. Long-term CI use is beneficial for prelingually-deafened children to improve auditory and speech performance.

Violation of identity-specific action-effect prediction increases pupil size and attenuates auditory event-related potentials at P2 latencies when action-effects are behaviorally relevant

Self-initiated sensory action effects are widely assumed to lead to less intense perception and reduced neural responses compared to externally triggered stimuli (sensory attenuation). However, it is unclear if sensory attenuation occurs in all cases of action-effect prediction. Specifically, when predicted action-effects are relevant to determine follow-up actions attenuation could be detrimental. We quantified auditory event-related potentials (ERP) in electroencephalography (EEG) when human participants created two-sound sequences by pressing two keys on a keyboard associated with different pitch, giving rise to identity-specific action-effect prediction after the first keypress. The first sound corresponded to (congruent) or violated (incongruent) the predicted pitch and was either relevant for the selection of the second keypress to correctly complete the sequence (Relevance) or irrelevant (Control Movement), or there was only one keypress and sound (Baseline). We found a diminished P2-timed ERP component in incongruent compared to congruent trials when the sound was relevant for the subsequent action. This effect of action-effect prediction was due to an ERP reduction for incongruent relevant sounds compared to incongruent irrelevant sounds at P2 latencies and correlated negatively with modulations of pupil dilation. Contrary to our expectation, we did not observe an N1 modulation by congruency in any condition. Attenuation of the N1 component seems absent for predicted identity-specific auditory action effects, while P2-timed ERPs as well as pupil size are sensitive to predictability, at least when action effects are relevant for the selection of the next action. Incongruent relevant stimuli thereby take a special place and seem to be subject to attentional modulations and error processing.

Potentiation of the muscarinic acetylcholine receptor 1 modulates neurophysiological features in a mouse model of Rett syndrome

Rett syndrome (RTT) is a neurodevelopmental disorder primarily caused by mutations in the X chromosome-linked gene Methyl-CpG Binding Protein 2 (MECP2). Restoring MeCP2 expression after disease onset in a mouse model of RTT reverses phenotypes, providing hope for development of treatments for RTT. Translatable biomarkers of improvement and treatment responses have the potential to accelerate both preclinical and clinical evaluation of targeted therapies in RTT. Studies in people with and mouse models of RTT have identified neurophysiological features, such as auditory event-related potentials, that correlate with disease severity, suggesting that they could be useful as biomarkers of disease improvement or early treatment response. We recently demonstrated that treatment of RTT mice with a positive allosteric modulator (PAM) of muscarinic acetylcholine subtype 1 receptor (M1) improved phenotypes, suggesting that modulation of M1 activity is a potential therapy in RTT. To evaluate whether neurophysiological features could be useful biomarkers to assess the effects of M1 PAM treatment, we acutely administered the M1 PAM VU0486846 (VU846) at doses of 1, 3, 10 and 30 ​mg/kg in wildtype and RTT mice. This resulted in an inverted U-shaped dose response with maximal improvement of AEP features at 3 ​mg/kg but with no marked effect on basal EEG power or epileptiform discharges in RTT mice and no significant changes in wildtype mice. These findings suggest that M1 potentiation can improve neural circuit synchrony to auditory stimuli in RTT mice and that neurophysiological features have potential as pharmacodynamic or treatment-responsive biomarkers for preclinical and clinical evaluation of putative therapies in RTT.

Low-Level Auditory Processing Correlates With Language Abilities: An ERP Study Investigating Sequence Learning and Auditory Processing in School-Aged Children.

Auditory processing and procedural learning deficits have been associated with language learning difficulties. We investigated the relationship of these skills and school-age language abilities in children with and without a history of late talking using auditory event related potentials (ERPs). Late talking (i.e., slow early language development) increases the risk of persistent language difficulties, but its causes remain unknown. Participants in this study were children with varying language abilities (n = 60). Half of the participants (n = 30) had a history of late talking. We measured procedural learning by manipulating the predictability of sine tone stimuli in a passive auditory ERP paradigm. Auditory processing was tested by examining how the presence of noise (increasing perceptual demands) affected the ERPs. Contrary to our hypotheses on auditory processing and language development, the effect of noise on ERPs did not correlate with school-age language abilities in children with or without a history of late talking. Our paradigm failed to reveal interpretable effects of predictability leaving us unable to assess the effects of procedural learning. However, better language abilities were related to weaker responses in a 75-175 ms time window, and stronger responses in a 150-250 ms time window. We suggest that the weak early responses in children with better language ability reflect efficient processing of low-level auditory information, allowing deeper processing of later, high-level auditory information. We assume that these differences reflect variation in brain maturation between individuals with varying language abilities.

Effects of attention on the processing of physical and abstract auditory regularities: An exploratory MMN study

The mismatch-negativity (MMN) component of the auditory event-related potential (ERP) reflects preattentive memory mechanisms encoding various types of regularities in the auditory environment. In an oddball paradigm, two types of deviant stimuli (in separate blocks) were presented among frequent standard stimuli: physical deviants (higher in pitch than the standards) and more complex, “abstract” deviants (tone pairs descending in pitch, presented among ascending standard tone pairs). The attentional load of the participant was manipulated under three conditions, where the participants either (1) watched a silent video, (2) played a computer game (Tetris) or (3) attended to the auditory stimuli and tried to detect infrequent target stimuli which were of lower intensity than the standard stimuli. The goal was to find out, whether the possible attention effects (suppression/enhancement) on the MMN are similar or different to stimuli requiring the extraction of either physical or abstract invariances. Both the physical and abstract deviants elicited in all conditions MMNs but no statistically significant amplitude differences between the conditions were found. The N2b and P3b components were elicited only in the attend condition and only by the soft target tones. The results further confirm that the MMN is a robust response to various types of regularity violations, showing no major effects of attentional manipulations. The results also suggest that the most commonly used primary task in MMN experiments, watching a silent video, usually keeps the participants' attention well enough directed away from the auditory stimuli. However, in cases where a cognitively more demanding but still participant-friendly primary task is needed, a simple computer game such as Tetris can be used, enabling better control of the participants’ attention and vigilance.

Global Field Time-Frequency Representation-Based Discriminative Similarity Analysis of Passive Auditory ERPs for Diagnosis of Disorders of Consciousness.

Behavioural diagnosis of patients with disorders of consciousness (DOC) is challenging and prone to inaccuracies. Consequently, there have been increased efforts to develop bedside assessment based on EEG and event-related potentials (ERPs) that are more sensitive to the neural factors supporting conscious awareness. However, individual detection of residual consciousness using these techniques is less established. Here, we hypothesize that the cross-state similarity (defined as the similarity between healthy and impaired conscious states) of passive brain responses to auditory stimuli can index the level of awareness in individual DOC patients. To this end, we introduce the global field time-frequency representation-based discriminative similarity analysis (GFTFR-DSA). This method quantifies the average cross-state similarity index between an individual patient and our constructed healthy templates using the GFTFR as an EEG feature. We demonstrate that the proposed GFTFR feature exhibits superior within-group consistency in 34 healthy controls over traditional EEG features such as temporal waveforms. Second, we observed the GFTFR-based similarity index was significantly higher in patients with a minimally conscious state (MCS, 40 patients) than those with unresponsive wakefulness syndrome (UWS, 54 patients), supporting our hypothesis. Finally, applying a linear support vector machine classifier for individual MCS/UWS classification, the model achieved a balanced accuracy and F1 score of 0.77. Overall, our findings indicate that combining discriminative and interpretable markers, along with automatic machine learning algorithms, is effective for the differential diagnosis in patients with DOC. Importantly, this approach can, in principle, be transferred into any ERP of interest to better inform DOC diagnoses.

EEG dynamic source imaging using a regularized optimization with spatio-temporal constraints.

One of the most important needs in neuroimaging is brain dynamic source imaging with high spatial and temporal resolution. EEG source imaging estimates the underlying sources from EEG recordings, which provides enhanced spatial resolution with intrinsically high temporal resolution. To ensure identifiability in the underdetermined source reconstruction problem, constraints on EEG sources are essential. This paper introduces a novel method for estimating source activities based on spatio-temporal constraints and a dynamic source imaging algorithm. The method enhances time resolution by incorporating temporal evolution of neural activity into a regularization function. Additionally, two spatial regularization constraints based on and norms are applied in the transformed domain to address both focal and spread neural activities, achieved through spatial gradient and Laplacian transform. Performance evaluation, conducted quantitatively using synthetic datasets, discusses the influence of parameters such as source extent, number of sources, correlation level, and SNR level on temporal and spatial metrics. Results demonstrate that the proposed method provides superior spatial and temporal reconstructions compared to state-of-the-art inverse solutions including STRAPS, sLORETA, SBL, dSPM, and MxNE. This improvement is attributed to the simultaneous integration of transformed spatial and temporal constraints. When applied to a real auditory ERP dataset, our algorithm accurately reconstructs brain source time series and locations, effectively identifying the origins of auditory evoked potentials. In conclusion, our proposed method with spatio-temporal constraints outperforms the state-of-the-art algorithms in estimating source distribution and time courses.

Pre-attentive and Attentive Auditory Event-related Potentials in Children With Attention-Deficit Hyperactivity Disorder and Autism.

Abnormalities in auditory processing are believed to play a major role in autism and attention-deficit hyperactivity disorder (ADHD). Both conditions often co-occur in children, causing difficulties in deciding the most promising intervention. Event-related potentials (ERPs) have been investigated and are showing promise to act as potential biomarkers for both conditions. This study investigated mismatch negativity (MMN) using a passive listening task and P3b in an active auditory go/no-go discrimination task. Recordings were available from 103 children (24 females): 35 with ADHD, 27 autistic, 15 autistic children with co-occurring ADHD, and 26 neurotypical (NT) children. The age range considered was between 4 and 17 years, but varied between groups. The results revealed increases in the MMN and P3b amplitudes with age. Older children with ADHD exhibited smaller P3b amplitudes, while younger autistic children showed reduced MMN amplitudes in response to phoneme changes compared to their NT counterparts. Notably, children diagnosed with autism and ADHD did not follow this pattern; instead, they exhibited more similarities to NT children. The reduced amplitudes of phonetically elicited MMN in children with autism and reduced P3b in children with ADHD suggest that the two respective ERPs can act as potential biomarkers for each condition. However, optimisation and standardisation of the testing protocol, as well as longitudinal studies are required in order to translate these findings into clinical practice.

Sex differences during development in cortical temporal processing and event related potentials in wild-type and fragile X syndrome model mice

BackgroundAutism spectrum disorder (ASD) is currently diagnosed in approximately 1 in 44 children in the United States, based on a wide array of symptoms, including sensory dysfunction and abnormal language development. Boys are diagnosed ~ 3.8 times more frequently than girls. Auditory temporal processing is crucial for speech recognition and language development. Abnormal development of temporal processing may account for ASD language impairments. Sex differences in the development of temporal processing may underlie the differences in language outcomes in male and female children with ASD. To understand mechanisms of potential sex differences in temporal processing requires a preclinical model. However, there are no studies that have addressed sex differences in temporal processing across development in any animal model of ASD.MethodsTo fill this major gap, we compared the development of auditory temporal processing in male and female wildtype (WT) and Fmr1 knock-out (KO) mice, a model of Fragile X Syndrome (FXS), a leading genetic cause of ASD-associated behaviors. Using epidural screw electrodes, we recorded auditory event related potentials (ERP) and auditory temporal processing with a gap-in-noise auditory steady state response (ASSR) paradigm at young (postnatal (p)21 and p30) and adult (p60) ages from both auditory and frontal cortices of awake, freely moving mice.ResultsThe results show that ERP amplitudes were enhanced in both sexes of Fmr1 KO mice across development compared to WT counterparts, with greater enhancement in adult female than adult male KO mice. Gap-ASSR deficits were seen in the frontal, but not auditory, cortex in early development (p21) in female KO mice. Unlike male KO mice, female KO mice show WT-like temporal processing at p30. There were no temporal processing deficits in the adult mice of both sexes.ConclusionsThese results show a sex difference in the developmental trajectories of temporal processing and hypersensitive responses in Fmr1 KO mice. Male KO mice show slower maturation of temporal processing than females. Female KO mice show stronger hypersensitive responses than males later in development. The differences in maturation rates of temporal processing and hypersensitive responses during various critical periods of development may lead to sex differences in language function, arousal and anxiety in FXS.

Auditory Event-related Potentials for Word Stimuli in Kannada Language Among Native Kannada Speakers with Dementia

Background: The P300 is a positive auditory event-related potential appearing around 300 msec post-oddball stimulus onset. Tone and monosyllabic stimuli have been widely used in P300 research, providing valuable insights into auditory perception, phoneme discrimination, language processing, and other cognitive processes. Bi-syllabic minimal pairs may be more challenging for some individuals because they require processing and discrimination of more complex phonemic structures. The aim of the study was to elicit and analyze the auditory event-related potentials for bi-syllabic word stimuli in the Kannada language among individuals with dementia. Method: The prospective study was conducted at the Department of Speech Pathology and Audiology. Ten native Kannada language speakers (five male; and five female) diagnosed with dementia, aged 55–70 years, were the participants. The naturally produced and recorded CVCV (Consonant vowel consonant vowel) tokens (/ko:ti/ and /ko:thi/ pair; /a: me/ and /a:ne pair) in Kannada were used in the auditory oddball paradigm. Results: The waveforms with positive peak for word (PPW) with clear morphology were used to obtain the latency and amplitude. Mean and Standard deviation (SD) value for the latency of the PPW was 545 ± 38 msec and the amplitude value of PPW was 2.5 ± 1.5 µV. Conclusion: The present study showed that when lengthier speech stimulus duration was used, the latency value of auditory event-related potential was higher. The study also showed that PPW is a reliable peak that could be used in the clinical population.

Automated ABR and MMN extraction using a customized headband for hearing screening

ObjectiveStimuli-elicited EEG responses, known as Event-Related Potentials (ERPs), reflect the health status of underlying electrophysiological processes and are frequently used for scanning sensory pathways. Current ERP extraction systems are expensive, complex, and bulky. This study aims to overcome these limitations by developing and validating a bimodal auditory ERP extractor headband. MethodsAn affordable, portable bimodal auditory ERP extractor was developed and validated for ABR (Auditory Brainstem Response) and MMN (Mismatch Negativity) response interpretation. Auditory stimuli were created using Presentation software. Adaptive filtering-based extraction was performed in EEGLAB (MATLAB) to derive the neural inferences. Extracted responses from n = 5 young adults were validated against CE-certified acquisition systems used in clinical practice. ResultsValidation results showed the grand average responses of ABR and MMN for n = 5 subjects matched. Furthermore, with and without stimuli ERP analysis showed significant differences for identified features (p = 0.00794 for ABR wave-V amplitudes, p = 1.22 * 10−5, and p = 2.62 * 10−5 for MMN peak latencies and area under the curves), ensuring that the response was due to the presented auditory stimuli. ConclusionThe results confirm the competency of the developed system to obtain MMN and ABR from young adults. A clear contrast between latency-amplitude scatter plots further ensures the competency of a developed system to acquire ABR and MMN. SignificanceThe novelty of the study is an easy-to-operate, affordable ERP extractor with adaptive filtering, wearable design, and configurable stimuli. This system can be a potential solution for large-scale hearing screening, providing detailed neural insights, including averaged responses and inter-trial variabilities.

Brain vital signs as a quantitative measure of cognition: Methodological implementation in a care home environment

IntroductionManaging cognitive function in care homes is a significant challenge. Individuals in care have a variety of scores across standard clinical assessments, such as the Mini-Mental Status Exam (MMSE), and many of them have scores that fall within the range associated with dementia. A recent methodological advance, brain vital sign monitoring through auditory event-related potentials, provides an objective and sensitive physiological measurement to track abnormalities, differences, or changes in cognitive function. Taking advantage of point-of-care accessibility, the current study evaluated the methodological feasibility, the assessment of whether a particular research method can be successfully implemented, of quantitatively measuring cognition of care home residents using brain vital signs. Secondarily, the current study examined the relationship between brain vital signs, specifically the cognitive processing associated N400 component, and MMSE scores in care home residents. Materials and methodsBrain vital signs used the established N100 (auditory sensation), P300 (basic attention), and N400 (cognitive processing) event-related potential (ERP) components. A total of 52 residents were enrolled, with all participants evaluated using the MMSE. Participants were assigned into homogeneous groups based on their MMSE scores, and were categorized into low (n = 14), medium (n = 17), and high (n = 13) MMSE groups. Both brain vital sign measures and underlying ERP waveforms were examined. Statistical analyses used partial least squares correlation (PLS) analyses in which both MMSE and age were included as factors, as well as jackknife approaches, to test for significant brain vital sign changes. ResultsThe current study successfully measured and analyzed standardized, quantifiable brain vital signs in a care home setting. ERP waveform data showed specific N400 changes between MMSE groups as a function of MMSE score. PLS analyses confirmed significant MMSE-related and age-related differences in the N400 amplitude (p < 0.05, corrected). Similarly, the jackknife approach emphasized the N400 latency difference between the low and high MMSE groups. Discussion and conclusionIt was possible to acquire brain vital signs measures in care home residents. Additionally, the current study evaluated brain vital signs relative to MMSE in this group. The comparison revealed significant decreasing in N400 response amplitude (cognitive processing) as a function of both MMSE score and age, as well as a slowing of N400 latency. The findings indicate that objective neurophysiological measures of impairment are detectable in care home residents across the span of MMSE scores. Direct comparison to MMSE- and age-related variables represents a critical initial step ahead of future studies that will investigate relative improvements in sensitivity, validity, reliability and related advantages of brain vital sign monitoring.