Study of brainstem auditory evoked response and biochemical markers in patients of alcohol use disorder

Objectives: Data available on brainstem auditory evoked response (BAER) and its correlation with biochemical parameters in patients of alcohol use disorder (AUD) in Indian population is scanty. Therefore, this study was undertaken to focus on the effects of AUD on BAER and liver enzymes. Materials and Methods: This case-control study included 40 males in the study group who had AUD and 40 healthy males in the control group in the age group of 20–60 years. The BAER was performed using octopus NCS/ EMG/EP (Clarity) machine. The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase and serum bilirubin were estimated in all the subjects. Results: We observed a highly significant increase in the absolute latencies of waves III and V and interpeak latencies (IPL) I-III and I-V of BAER in the patients of AUD in this study. Significant increase in the liver enzymes and especially AST/ALT ratio of patients of AUD was seen which indicated towards subclinical alcoholic hepatitis. The latencies of waves of EPs (waves III, V, IPL I-III and IPL I-V) were positively correlated with the biochemical parameters and duration of AUD. Conclusion: Our findings indicated that AUD lead to the increase in brainstem transmission time and also lead to subclinical alcoholic hepatitis which is reflected by the increase in the liver enzymes. We concluded that chronic alcohol consumption affected the auditory pathways and delayed the auditory transmission time which was suggestive of possible demyelination of auditory tracts.

Ketamine-xylazine anesthesia depth affects auditory neuronal responses in the lateral superior olive complex of the gerbil

Studies of in vivo neuronal responses to auditory inputs in the superior olive complex (SOC) are usually done under anesthesia. However, little attention has been paid to the effect of anesthesia itself on response properties. Here, we assessed the effect of anesthesia depth under ketamine-xylazine anesthetics on auditory evoked response properties of lateral SOC neurons. Anesthesia depth was tracked by monitoring EEG spectral peak frequencies. An increase in anesthesia depth led to a decrease in spontaneous discharge activities and an elevated response threshold. The temporal responses to suprathreshold tones were also affected, with adapted responses reduced but peak responses unaffected. Deepening the anesthesia depth also increased first spike latency. However, spike jitter was not affected. Auditory brainstem responses to clicks confirmed that ketamine-xylazine anesthesia depth affects auditory neuronal activities and the effect on spike rate and spike timing persists through the auditory pathway. We concluded from those observations that ketamine-xylazine affects lateral SOC response properties depending on the anesthesia depth.

Brain auditory evoked response test, the standard method for the diagnosis of the hereditary deafness in dogs

Hearing deficiency is one of the most common hearing impairments that affect humans and other mammalian alike. Hearing loss is not painful or a life-threatening change but can endanger the patient by taking into account a large number of breeds predisposed to hereditary deafness, this short communication aims to synthesize the steps and the method for BAER test. For the affected breeds, the BAER test is recommended starting at the age of two months

Feed-forward inhibition fine-tunes response timing in auditory-vocal interactions

The ability to regulate vocal timing is a fundamental aspect of communicative interactions for many species, including conversational speech among humans, yet little is known about the neural circuitry that regulates the input-dependent timing of vocal replies. Exploring this topic in the zebra finch premotor area HVC, we identify feed-forward inhibition as a key regulator of vocal response timing. Based on a spiking network model informed by behavioral and electrophysiological data from communicating zebra finches, we predicted that two different patterns of inhibition regulate vocal-motor responses. In one scenario, the strength of production-related premotor inhibition translates into plasticity in vocal response delays. In the other scenario, fast transient interneuron activity in response to auditory input results in the suppression of call production while a call is heard, thereby reducing acoustic overlap between callers. Extracellular recordings in HVC during the listening phase confirm the presence of auditory-evoked response patterns in putative inhibitory interneurons, along with corresponding signatures of auditory-evoked activity suppression. The proposed model provides a parsimonious framework to explain how auditory-vocal transformations can give rise to vocal turn-taking and highlights multiple roles of local inhibition for behavioral modulation at different time scales.

Bilingualism and Cognitive and Auditory Processing: A Comprehensive Review

Objectives: Bilingualism and multilingualism are on the rise in many parts of the world. Learning and using other languages, in addition to the expected impact on language domains, can affect non-linguistic fields such as attention, working memory, cognitive control, and auditory processing. The objective of this study was a comprehensive review of the bilingual advantage and disadvantages with emphasis on its effect on the cognitive process and its relationship with auditory processing. Methods: A total of 133 articles were initially found in this field. According to the inclusion and exclusion criteria of the review, 84 related articles were entered into this study. Then we searched articles published 2005-2020 in Science Direct, Scopus, Google Scholar, and PubMed databases. Keyword and MeSH terms were used in the search process: “bilingualism”, “cognitive process”, “auditory process”, and “auditory attention”. Results: Studies showed that bilingualism not only has advantages in the linguistic domain but also affects the cognitive domain, especially auditory attention, auditory memory capacity, and inhibitory control. Also, it has a protective effect against cognitive decline in aging. Structural changes in the brain in bilinguals support these effects. Most studies reported that enhanced attentional requests of bilingual exchange amplify connectivity among cognitive functions like attentional rein and auditory processing. These effects create more constancy in the auditory evoked response in bilinguals. Discussion: Learning foreign languages could provoke the autonomic sound processing capability of the auditory organ and make it highly efficient in challenging listening conditions. It also affects other cognitive processes such as auditory memory. However, a comprehensive framework for this relationship is still unknown, and further research is needed, especially to support neurophysiological evidence.

EEG-Based Focus Estimation Using Neurable's Enten Headphones and Analytics Platform

We introduce Neurable's research on focus using our recently developed Enten EEG headphones. First we quantify Enten's performance on standard EEG protocols, including eyes-closed alpha rhythms, auditory evoked response and the P300 event-related potential paradigm. We show that Enten's performance is on-par with established industry-standard hardware. We then introduce a series of experimental tasks designed to mimic how focus might be maintained or disrupted in a real-world office setting. We show that (A) these tasks induce behavioral changes that reflect underlying changes in focus levels and (B) our proprietary algorithm detects these changes across a large number of sessions without needing to adjust the model per participant or recording session. Through manipulation of our experimental protocol, we show that our algorithm is not dependent on gross EMG artifacts and it is driven by changes in EEG. Finally, we evaluated the model's performance on the same subject across several days, and show that performance remained consistent over time. Our model correctly captured 80% ± 4.1% of distractions present in our experiments with statistical significance. This indicates that our model generalizes across subjects, time points, and conditions. Our findings are based on EEG data collected from 132 participants across 337 sessions and 45 different experiments.

The Onset–Offset N1–P2 Auditory Evoked Response in Individuals With High-Frequency Sensorineural Hearing Loss: Responses to Broadband Noise

Purpose Clinical use of electrophysiologic measures has been limited to use of brief stimuli to evoke responses. While brief stimuli elicit onset responses in individuals with normal hearing and normal central auditory nervous system (CANS) function, responses represent the integrity of a fraction of the mainly excitatory central auditory neurons. Longer stimuli could provide information regarding excitatory and inhibitory CANS function. Our goal was to measure the onset–offset N1–P2 auditory evoked response in subjects with normal hearing and subjects with moderate high-frequency sensorineural hearing loss (HFSNHL) to determine whether the response can be measured in individuals with moderate HFSNHL and, if so, whether waveform components differ between participant groups. Method Waveforms were obtained from 10 participants with normal hearing and seven participants with HFSNHL aged 40–67 years using 2,000-ms broadband noise stimuli with 40-ms rise–fall times presented at 50 dB SL referenced to stimulus threshold. Amplitudes and latencies were analyzed via repeated-measures analysis of variance (ANOVA). N1 and P2 onset latencies were compared to offset counterparts via repeated-measures ANOVA after subtracting 2,000 ms from the offset latencies to account for stimulus duration. Offset-to-onset trough-to-peak amplitude ratios between groups were compared using a one-way ANOVA. Results Responses were evoked from all participants. There were no differences between participant groups for the waveform components measured. Response × Participant Group interactions were not significant. Offset N1–P2 latencies were significantly shorter than onset counterparts after adjusting for stimulus duration (normal hearing: 43 ms shorter; HFSNHL: 47 ms shorter). Conclusions Onset–offset N1–P2 responses were resistant to moderate HFSNHL. It is likely that the onset was elicited by the presentation of a sound in silence and the offset by the change in stimulus envelope from plateau to fall, suggesting an excitatory onset response and an inhibitory-influenced offset response. Results indicated this protocol can be used to investigate CANS function in individuals with moderate HFSNHL. Supplemental Material https://doi.org/10.23641/asha.14669007