Latency Of Wave Research Articles

Median to ulnar nerve comparison on diagnosis of carpal tunnel syndrome in patients with diabetic polyneuropathy - A neurophysiological study.

<p style="text-align: justify;"><strong>Background and purpose </strong>&ndash; To analyze the utility of median nerve (MN) to ulnar nerve (UN) comparative parameters on the diagnosis of carpal tunnel syndrome (CTS) in diabetic patients with distal symmetrical sensorimotor polyneuropathy (DSMPNP). <br><br><strong>Methods</strong> &ndash; Patients who were referred to our electroneuromyography laboratory within the last two years were included. We compared the diagnostic accuracy values of traditional MN conduction parameters, and the MN-to-UN comparative tests on electrodiagnosis of CTS between the patients with DSMPNP involving the nerves of upper and lower extremities (UEI-positive group), and the ones without the involvement of upper extremities (UEI-negative group). <br><br><strong>Results</strong> &ndash; There were 64 upper extremities in the UEI-positive group and 70 patients in the UEI-negative group. The most accurate traditional parameter was MN distal motor latency (DML) with a diagnostic accuracy of 70.2% whereas the most accurate comparative technique was the second lumbricalinterosseous DML difference (2L-INT DMLD) with an accuracy of 81.3%. (p=0.03). In addition, when compared diagnostic accuracy values of MN parameters with their corresponding comparative parameters in the UEI-positive group which carries the major diagnostic challenges for detecting co-morbid CTS, MN to UN minimum F wave latency (mFWL) difference, SNAP amplitude ratio on the ring finger (RF), and 2L-INT DMLD had higher accuracy values than MN mFWL, MN SNAP amplitude on RF, and MN DML on lumbrical muscle, respectively (p&lt;0.05 for all comparisons). <br><br><strong>Conclusion</strong> &ndash; MN to UN comparative studies have high accuracy values in electrodiagnosis of CTS in DSMPNP. In particular, 2L-INT DMLD could be helpful to overcome the diagnostic difficulty in the presence of UEI as an additional conduction technique.</p>.

Ocorrência de alterações nos potenciais evocados auditivos de fumantes: revisão sistemática da literatura

ABSTRACT Purpose To verify the occurrence of abnormal auditory evoked potentials (AEP) tests in adult smokers. Research strategies Systematic review of the literature according to the PRISMA guidelines, to answer the question: “Are there any changes in the AEP results in adult smokers?”, PECOS strategy. Research carried out on PubMed, Embase, CINAHL, LIVIVO, Scopus, Web of Science, LILACS and Scielo databases. Additional search of gray literature: Google Scholar and ProQuest hand searching of reference lists of the included studies. Selection criteria Cross-sectional studies were selected, without restriction on the year of publication and language. Data analysis First, the titles and abstracts of all the studies were analyzed, followed by the full reading of the eligible studies. Results 898 articles were collected, after the duplicate studies were removed and after blind analysis by three researchers, 8 studies of the observational type were selected. Most studies have found an association between active smoking and changes in electrophysiological tests. Conclusion Normal hearing adult smokers present alterations in short and long AEP. In the auditory brainstem response, the main altered components were the increase in waves latencies of I and III and in the interpeaks I - III and III - V, as well as a decrease in the amplitude of the waves. In Mismatch Negativity, there was a significant increase in wave amplitude and latency. In the long latency potential, P300, there was an increase in latencies and decreased amplitudes in the components N1 (in Fz) and P3.

Proactively Predicting Dynamic 6G Link Blockages Using LiDAR and In-Band Signatures

Line-of-sight link blockages represent a key challenge for the reliability and latency of millimeter wave (mmWave) and terahertz (THz) communication networks. To address this challenge, this paper leverages mmWave and LiDAR sensory data to provide awareness about the communication environment and proactively predict dynamic link blockages before they occur. This allows the network to make proactive decisions for hand-off/beam switching, enhancing the network reliability and latency. More specifically, this paper addresses the following key questions: (i) Can we predict a line-of-sight link blockage, before it happens, using in-band mmWave/THz signal and LiDAR sensing data? (ii) Can we also predict when this blockage will occur? (iii) Can we predict the blockage duration? And (iv) can we predict the direction of the moving blockage? For that, we develop machine learning solutions that learn special patterns of the received signal and sensory data, which we call pre-blockage signatures, to infer future blockages. To evaluate the proposed approaches, we build a large-scale real-world dataset that comprises co-existing LiDAR and mmWave communication measurements in outdoor vehicular scenarios. Then, we develop an efficient LiDAR data denoising algorithm that applies some pre-processing to the LiDAR data. Based on the real-world dataset, the developed approaches are shown to achieve above 95% accuracy in predicting blockages occurring within 100 ms and more than 80% prediction accuracy for blockages occurring within one second. Given this future blockage prediction capability, the paper also shows that the developed solutions can achieve an order of magnitude saving in network latency, which further highlights the potential of the developed blockage prediction solutions for wireless networks.

A comparative study of visual evoked potential parameters in type 2 diabetes mellitus patients with increasing duration

Background: Type 2 diabetes mellitus (T2DM) is endocrine disorder showing increasing prevalence worldwide. Chronic hyperglycemia of diabetes affects various organs of our body and causes dysfunction and failure of them. Diabetic retinopathy is a grave complication of diabetes mellitus. Diabetes causes neurodegeneration in retina well before the frank retinopathy. Early detection of these changes by visual evoked potentials (VEPs) may prevent the development of this complication in future, so it can be used as a screening test. Aims and Objectives: The study aimed to compare the VEP changes with the duration of T2DM. Materials and Methods: An analytical case–control study was done after obtaining Ethical Committee permission. VEPs were recorded with RMS EMG EP MK II machine. The duration of the diabetes was used to divide patients into two groups: Group I - 30 patients with disease duration &lt;15 years; and Group II - 30 patients with T2DM with disease duration &gt;15 years. Analysis and processing of the data was done by using statistical software SPSS23.0 using t-test. The significance level was taken as P &lt; 0.05. Results: The comparative analysis between groups showed significant prolongation in latencies of P100 wave and N 145 wave in group II and reduced N75 - P100 amplitude in group II, though it was not statistically significant. Conclusion: It is concluded that the visual pathway is affected by diabetes and VEP changes are correlated with its duration. Therefore, VEPs can be used as a prognostic marker.

Brain stem auditory evoked potentials in type 2 diabetes mellitus patients at varying frequencies.

As per the World Health Organization, in 2005, more than 180 million people had diabetes worldwide. This figure will be more than double by 2030. Neuropathy is common and late complication of diabetes mellitus (DM). Sensory neural hearing loss which is severe at higher frequencies has been reported in Type 2 DM patients. Auditory nerve tract damage increases the latency and reduces the amplitude of the response. Evoked potential recordings evaluate the neural pathways in the central nervous system. Brainstem auditory evoked potentials (BAEP) localize anatomic structures using different waves and detect acoustic and central neuropathy (CN). Hence, brainstem evoked response of audiometry (BERA) is used widely in clinical set up. 1. To record BERA waves in normal subjects with normal blood sugar levels (hemoglobin A1C [HbA1C] <5.4. 2. To record BERA waves in Type 2 DM patients. (HbA1C >6.5). To study the BERA parameters with the normal subjects with blood sugar subjects and compare them with Type 2 DM patients. n = 30, Type 2 DM patients between the age of 35-50 years of either sex were chosen from the Diabetic Clinic of GMC, Aurangabad, Maharashtra. HbA1C test for glycemic control and BERA waves to assess CN were recorded. n = 30 normal subjects with normal blood sugar with age and sex-matched above tests were performed. Unpaired Student's t-test. Mean ± Standard deviation of the absolute latency and interpeak latency of BERA waves at 2, 4, and 6 KHz at 80 dB in Type 2 DM patients were delayed and found to be significant as compared to control group. The above study explains that if BAEP is recorded at higher frequencies like 6 KHz and at 80 dB, CN involvement can be detected earlier in diabetic patients. Hence, it is recommended to carry out BERA in diabetic patients at least once in a year.

Vestibular evoked myogenic and auditory brainstem evoked potentials in a female migraine population.

<p>The purpose&nbsp;of the present study was to evaluate ocular vestibular evoked myogenic potential (oVEMP), cervical vestibular evoked myogenic potential (cVEMP), and brainstem auditory evoked potential (BAEP) response characteristics and to understand the pathophy&shy;siology of vestibular dysfunction in female migraineurs with vertigo symptoms. We also aimed to assess the electrophysiological di&shy;&shy;agnostic significance of the VEMP respon&shy;ses in vestibular migraine (VM).&nbsp;</p>. <p>23 patients with migraine without aura (MoA), 23 patients with VM, and 20 sex-and age-matched healthy controls, a total of 66 female participants were enrolled in this study. The outcome parameters were asymmetry ratios (ARs), amplitudes of oVEMP, cVEMP, N1P1, P13N23, and the respective latencies (mean &plusmn; SD). From the BAEP graphs, absolute and interpeak interval latencies of waves were analyzed.&nbsp;</p>. <p>30.4% of the MoA group and 21.7% of the VM group had uni- or bilaterally absent cVEMP responses which were statistically significant only in the MoA group (p=0.035) in comparison to control group. Both groups displayed statistically insignificant absent or asymmetrical responses for oVEMP (13.1%). Cervical VEMP P13 and N23 latency, peak-to-peak amplitude, interaural latencies, and amplitude ARs did not show any significant difference between MoA and VM patients and healthy controls. No significant difference was detected among the three groups in the oVEMP and BAEP parameters.</p>. <p>Although absent cVEMP responses were more common in MoA and VM patients than in healthy individuals, the VEMP and BAEP test results should not be used in the differential diagnosis of VM and MoA.&nbsp;</p>.

Comparing Auditory Brain Stem Responses and Transient Otoacoustic Emissions in Premature Infants with Auditory Developmental Delay: Evidence of Temporary Auditory Neuropathy.

Premature birth causes some permanent or temporary abnormalities in the hearing system of the newborn. Inadequate development of the central auditory nervous system and balance, as well as the delay in the formation of the nerve myelin, can be the cause of many hearing disorders, including permanent or temporary auditory neuropathy spectrum disorder (ANSD). The present study aims to identify and understand developmental delay disorder in the hearing system of infants and investigate the possibility of temporary auditory neuropathy in infants. In this comparative analytical study, twenty premature infants were randomly selected for hearing tests using auditory brainstem response and transient otoacoustic emissions at the time of discharge and three months after the first evaluation. The different components of these tests were analyzed and compared before and after developing the auditory system. The OAEs test showed a signal-to-noise ratio above six dB with appropriate amplitudes in all infants. The grand average waveform of the ABR showed a significant difference between the amplitudes of waves III and V before and after maturation in both ears (p<0.05). In addition, the absolute latency of waves, specifically III and V, showed a significant difference between the two assessment times (0.05). The present study confirmed the occurrence of temporary ANSD or delayed maturation in premature infants following the lack of complete growth and myelination of auditory nerve fibers. There is a need to determine the hearing status of premature infants by frequent examinations and prevent any unnecessary prescription of amplifications.

An observational study to assess the influence of karate training on auditory evoked potential

Regular martial art training has shown positive benefits in executive functioning and reaction time facilitation. However, influence of karate training on brain stem neurophysiology is an untouched area of research. This study investigates the impact of regular karate training on brain stem auditory evoked potential (BAEP) in male school going children. Thirty subjects were assessed and compared under two groups: 15 experienced male karate practitioners (9.5 ± 1.26 years); 15 age-gender matched active controls (10.6 ± 1.57 years). The latencies (L), inter peak latencies (IPL) and amplitude (A) of the auditory waves I–V generated in the brain stem region were measured. Significant differences resulted in the left ear latencies of wave I, wave II, and left and right ear of wave III; also, IPL of waves III–V of both ears and I–V of the right ear were significantly shorter in the karate practitioners. The shorter latencies are due to faster synaptic transmissions in the corresponding physiological neuro-generators of the brainstem auditory waves that connect cognitive and sensory signalling pathways. Karate practitioners showed better neural conduction and adaptation to auditory cues, which may have developed through regular training of self-defence not just as a martial art but as a mind body exercise.

Change of brainstem auditory-evoked potential in vertebrobasilar transient ischemic attack patients

Background: Transient ischemic attack describes the symptoms of the nervous system which occurs due to insufficient circulation that lasts for &lt;24 h. Its clinical manifestations tend to disappear quickly and it is also considered as an indicator of stroke. Brainstem auditory-evoked potentials are responses of the brainstem by auditory stimulation. Vertebrobasilar (VB) transient ischemia can cause brainstem ischemia which can induce BAEP changes. Hence, it becomes necessary to evaluate the electrophysiological changes in VB transient ischemic attack (VBTIA) patients so that early detection of neuronal changes and prevention of full-blown stroke. Aims and Objectives: The aim of this study was to compare the changes in brainstem auditory-evoked potential in VB TIA patients with normal subject. Materials and Methods: Auditory-evoked potential was recorded in 40 patients with VBTIA and 40 normal control groups. This study was conducted at the Research Laboratory, Department of Physiology, Thanjavur Medical College, Thanjavur. Results: The absolute latency of wave V was prolonged and a reduction in amplitude of wave V was observed in patients with VBTIA and it was found to be statistically significant. Conclusion: This study is very much useful to identify the early detection of the progression of stroke in VB TIA patients. Further studies are required to evaluate the correlation between the electrophysiological parameters and progression into stroke so that preventive measures can be used to prevent early involvement of Stroke.

A Rare Cause of Paroxysmal Movement Disorder Associated with TBC1D24 Gene Mutation in Two Siblings.

A Rare Cause of Paroxysmal Movement Disorder Associated with TBC1D24 Gene Mutation in Two Siblings.

Comparison of brainstem auditory evoked potentials and event-related potential-300 parameters among different severity levels of depression: A study on adult patients

Background: Depression, a serious mental health issue, linked to disruption in mood and cognitive abilities. One of the most crucial elements in the diagnosis and treatment of depression is its severity. Few researches have been conducted to determine the severity of depression on the brainstem and cognitive functioning. Therefore, this study focuses on evaluating brainstem auditory evoked potentials (BAEPs) and event-related potential (P300) parameters among depressive patients regarding severity levels (mild, moderate, and severe). Aims and Objective: The study aims to assess BAEPs and ERP (P300) parameters among different severity levels (mild, moderate, and severe) of depressive patients and compare the results. Materials and Methods: This cross-sectional study included 55 depressive patients divided into three groups fulfilling the diagnostic criteria of the diagnostic and statistical manual of mental disorders, fourth edition (DSM-IV) for major depressive disorder (MDD). The severity of depression was measured by the Hamilton Depression Rating Scale (HDRS). The BAEPs and ERP (P300) were recorded using NeuroStim-NS 21 and auditory oddball paradigm, respectively. Data were analyzed by one-way ANOVA followed by post hoc tests. P &lt; 0.05 was considered statistically significant. Results: A significant difference was found among three groups of depression severity in BAEPs, wave I for the right ear and IPL I-III for the left ear. P300 wave latency was found to be significant between mild and moderate, and also between moderate and severe groups. Conclusion: The reported differences in BAEPs and ERP P300 latencies can be attributed to the delay in auditory processing of depressive individuals.

IMPLEMENTATION OF VISUAL EVOKED POTENTIAL FOR THE DETECTION OF PRERETINOPATHY AND PROGNOSTICATION IN DIABETES MELLITUS

Introduction: Diabetic Retinopathy (DR) is one of the complications of Diabetes Mellitus (DM) which affects the retinal blood vessels. It is one of the preeminent causes of blindness in the age group of 20 to 74 years albeit that visual loss due to it may be preventable by adequate glycaemic control. Visual Evoked Potential (VEP) can be used in diagnosis of retinal changes and ascertainment of prognosis can be done by it. Aim: To evaluate the ability of VEP in identifying preclinical neuro-degenerative changes in patients with diabetic preretinopathy by studying changes in VEP. Materials and Methods: This study comprises of 30 diabetic patients without retinopathy and 30 non diabetic controls. Patients were selected from the outpatient Department of Ophthalmology for the screening of DR. Latency of P100 was analysed because of its reliability and less inter-subject variability. Mean P100 wave latency of both groups were compared and analysis was done regarding any discrepancy in P100 wave latency with respect to the duration and the control of diabetes. Data was analysed using IBM-SPSS 27. Student's t- test was applied when two groups were compared whereas Analysis of Variance test was applied for multiple group comparisons. The p value &lt;0.001 was considered statistically signicant. Results: There was signicant prolongation of P100 latency in diabetics without retinopathy. It was also observed that there was positive correlation between prolongation of P100 latency and duration of diabetes. Conclusion: VEP could be a better tool for the detection of very early retinal changes before any clinical evidence of retinopathy has set in. Adequate glycaemic control, dietary modication, appropriate dosage of medications could prevent the early development of retinopathy if done at this stage

A cross-sectional analysis to study the effects of mobile use on brainstem auditory response in young healthy male adults

Background: The intensive use of mobile phones has given rise to adverse effects concerning the potential influences of electromagnetic fields on human health. The ear, being the closest, is the direct recipient of electromagnetic radiation, thus making it the most likely affected organ. The present study assessed the effects of mobile usage on brainstem auditory responses in young healthy male adults using brainstem-evoked response audiometry. Aims and Objectives: The present study aimed to evaluate the effects of long-term repeated exposure to mobile phones on the hearing of young healthy male adults by assessing and comparing absolute wave latencies and interpeak latencies (IPLs) of brainstem auditory responses. Materials and Methods: The cross-sectional study was conducted using the RMS EMG SALUS 2C machine in the Physiology Department of SMS Medical College, Jaipur. This was an analytical type of observational study design incorporating a total of 70 young healthy male adults from SMS Medical College, Jaipur, in which Group I was using mobile for &gt;2 h/day for the duration of &gt;1 year and &lt;5 years and Group II was using mobile for &gt;2 h/day for the duration of more than 5 years. Results: The IPL I–III and I–V of the right ear of Group II was significantly prolonged (P &lt; 0.05) compared to IPL I–III and I–V of the right ear of Group I. Conclusion: This study revealed a significant prolongation of IPLs in the right ear of Group II mobile users associated with duration of usage.

Study of Auditory Brainstem Evoked Response at Varying Frequencies in Subclinical Hypothyroid Subjects.

Hearing deterioration in hypothyroid subject was documented by Kemp. Cristiane et al. reported delayed waves latency in subclinical hypothyroid subjects. Recording of auditory brain stem evoked response in subclinical hypothyroid subjects at 80 dB and varying frequencies has been done. Case control study. Group 1, N = 30 control subjects, free T3, free T4, thyroid stimulating hormone (TSH) within normal range. Group 2, N = 30 subclinical hypothyroid subjects, TSH was between 4.6-8 microIU/L. Student Unpaired t test was done. Those on epileptic, neuroleptics, depression, psychosis drugs, inflammatory, proliferative, traumatic ear disorder, smokers, on tobacco, COVID-19 positive subjects, altered sensorium, drug abuse, diabetes mellitus, neuropathy, hypertension, cardiac arrhythmia, family history of hearing disorder, and furosemide drug were excluded. Auditory brainstem evoked response (ABER) done. Mean ± SD of Brainstem evoked response auditory (BERA) waves III, V, interpeak latencies at 80 dB, 2, 4,6 KHz reported delay and significant in subclinical hypothyroid group as compared to control. BERA study at 6 KHz and 80 dB detects central neuropathy earlier in subclinical hypothyroid patients.

Auditory function assessment in patients with chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease is a multisystem disease with multiple comorbidities. Hearing is dependent on the cochlear functions that may be affected by oxygenation. Affection of hearing is problematic and represents a major concern that should be seriously investigated as an important comorbidity in chronic obstructive pulmonary disease patients. To assess auditory status among chronic obstructive pulmonary disease patients. The current study was carried out at Al-Azhar University Hospitals, Cairo, from 1 August 2021 to 2022, including 120 participants. In addition to the control group (60 healthy participants), there were two study groups: chronic obstructive pulmonary disease patients with respiratory failure group (30 patients) and non-respiratory failure group (30 patients). Hearing functions were studied using pure tone audiometry, and auditory brain stem response. There was statistically significant hearing impairment in chronic obstructive pulmonary disease patients in comparison to control group. The hearing impairment was more significant in chronic obstructive pulmonary disease with respiratory failure group in comparison to chronic obstructive pulmonary disease without respiratory failure group. The auditory impairment shows a negative interrelationship with oxygen tension (PaO2) and a positive interrelationship with the smoking index. Hearing affection was meaningfully higher among chronic obstructive pulmonary disease patients and more prominent in patients with respiratory failure. Hypoxia results in deterioration of pure tone audiometry and increased absolute and interpeak latencies in auditory brain stem response. At every frequency, the mean pure tone audiometry thresholds were higher for chronic obstructive pulmonary disease groups than control group albeit remaining in the mild to moderate area of hearing loss. Retro-cochlear affection was suggested among patients with chronic obstructive pulmonary disease as evidenced with the prolongation of auditory brain stem response waves latencies.

Identification of Neurophysiological Markers of Verbal Information Processing Using Cognitive Evoked Potentials for Studying Schizophrenia Spectrum Disorders.

Cognitive evoked potentials were studied in 40 students of higher school with high and low (control) scores obtained on the Schizotypal Personality Questionnaire (SPQ) in response to the presentation of visual verbal information in the form of agreed word-combinations. In the first series of presentations, it was necessary to refer the attribute to one of the categories and to read the noun silently (non-target condition). In the second series, the attribute should be read silently, and then the following noun has to be categorized (target condition). There has been performed a cluster analysis of the evoked potential curves obtained in response to the noun presentation in the target and non-target conditions in the groups of participants with high and low scores gained on SPQ. Processing of the verbal stimulus under passive reading conditions and under the conditions of word categorization within the frameworks of a simple context has shown that in the group with low scores on the schizotypal questionnaire, lateralization of the N150 component to the left side was observed in contrast to the group with high scores. In this group, increase of the N400 component amplitude was found in response to the words presented for their passive reading in comparison with the categorization condition. On the contrary, in the group with high schizotypy scores, the N400 component appeared to be insensitive to the type of the task, i.e. neurophysiological differences were not expressed between reading and performing stimuli categorization task. These persons were found to have the decreased amplitude of the late positive component as compared to the control group under the condition of passive reading of the words. Increase of the late negative wave amplitude was registered in response to the target words subjected to categorization in comparison with reading in both groups of participants. Insufficiency of language lateralization and deficit connected with the language networks being activated automatically at the initial stage of word recognition are observed in the examined persons with schizotypy. Additionally, processing of the information in these persons at the stage of lexical-semantic processes is weakly modulated by the task imposing different requirements on the level of mental activity control. Some reduction of mnestic process activation is also possible, which is manifested during passive reading of the words, but not in the conditions of their categorization. The research conducted may serve as a starting point for a more detailed and long-term study of the fundamental mechanisms of impairment in information processing in the course of clinically evident pathology formation. In the applied aspect, the work may be considered as a contribution to the ongoing search for neurophysiological markers for early diagnosis of schizophrenia spectrum disorders.

Short-term transcutaneous trigeminal nerve stimulation does not affect visual oddball task and paired-click paradigm ERP responses in healthy volunteers

Recent research suggests that transcutaneous trigeminal nerve stimulation (TNS) may positively affect cognitive function. However, no clear-cut evidence is available yet, since the majority of it derives from clinical studies, and the few data on healthy subjects show inconsistent results. In this study, we report the effects of short-term TNS on event-related potentials (ERP) recorded during the administration of a simple visual oddball task and a paired-click paradigm, both considered useful for studying brain information processing functions. Thirty-two healthy subjects underwent EEG recording before and after 20min of sham- or real-TNS, delivered bilaterally to the infraorbital nerve. The amplitude and latency of P200 and P300 waves in the simple visual oddball task and P50, N100 and P200 waves in the paired-click paradigm were measured before and after treatment. Our results show that short-term TNS did not alter any of the ERP parameters measured, suggesting that in healthy subjects, short-term TNS may not affect brain processes involved in cognitive functions such as pre-attentional processes, early allocation of attention and immediate memory. The perspective of having an effective, non-pharmacological, non-invasive, and safe treatment option for cognitive decline is particularly appealing; therefore, more research on the positive effects on cognition of TNS is definitely needed.

Effects of Unilateral Hearing Loss on Speech-Evoked Auditory Brainstem Responses and Reading: A Preliminary Study.

The purpose of this study was to determine whether the speech-evoked auditory brainstem responses (sABRs) obtained by stimulating the ear with normal sensitivity in children with unilateral hearing loss (UHL) were different from that of children with normal hearing (NH), and to explore correlations between the sABR findings and measures of reading. Eleven children with UHL and 11 children with NH were tested via the BioMARK sABR protocol using the syllable /da/; latency and amplitudes of Waves V, A, C, D, E, F, and O were measured. Participants also were tested on the Phonemic Synthesis Test (PST) and the Woodcock Reading Mastery Test-Revised (WRMT-R), particularly the Reading Readiness, Basic Skills, and Comprehension subtests. Multivariate analysis of variance testing showed a significantly higher amplitude for Wave A for the NH group as compared to the UHL group. Separate ANOVAs also found significantly lower scores for the UHL group compared to the NH group on Basic Skills and Comprehension subtests of the Woodcock. Significant positive Spearman rho correlations were found for the UHL group between wave amplitudes for V, A, and O and the Reading Readiness score, and between wave amplitudes for V, A, D, and O and the Reading Comprehension score. A significant correlation also was found between the Total Reading score and wave amplitudes for V and A. No such correlations were found between wave amplitude and Woodcock scores for the NH group. Further testing of the UHL data found significant relationships between the pure-tone average of the hearing loss ear and the Basic Skills, Comprehension, and Total Reading scores from the WRMT-R. There was also a significant correlation between the PST score and Wave C amplitude. There may be a connection between speech encoding and measures of reading in children with UHL.

Enigmatic doubly scattered tube waves at a crosswell seismic survey

SUMMARY Enigmatically strong tube waves continue to exist long after the direct wave during repeat crosswell-monitoring surveys at the Nagaoka CO2 injection site in Japan. The tube waves, which have linear moveouts with velocities of 1.29 and 1.41 km s−1 at plastic and steel casings, respectively, are generated by double scattering on the shallow side of the wells. We characterize wavefields to confirm that these late coda waves are tube waves that are excited at the source well, propagate upward, then travel to a receiver well as a body wave, and finally propagate downward along the receiver well. Even though these tube waves result from second-order scattering, they have large amplitudes because of the relatively short distance between source and receiver wells. Because these waves propagate along both wells many times, we can extract detailed information of wave propagation by averaging them to increase the signal-to-noise ratio. We first use the tube waves to relocate sources and receivers between multiple monitoring surveys, demonstrating our ability to correct the severe noise caused by location errors that frequently degrades the repeatability of time-lapse surveys. Then, we apply an inversion based on the physics of tube waves to estimate the location and strength of the scatterers and find that they are predominantly located in the shallow segment of the wells, above the sources, and infer that they are related to local fractures and/or wellbore conditions because their locations do not correspond to the well geometry. Lastly, we use the tube waves to accurately estimate subsurface velocities along the wells. The estimation is stable and robust, and the velocities follow the general trend of subsurface structure seen in the well log data. Due to the receiver spacing, tube-wave analysis cannot resolve a thin, high-velocity layer at the CO2 reservoir. By combining tube waves observed during different stages of the monitoring survey, we can estimate the time-lapse changes of the subsurface velocities.

Event-Related Potential Correlates of Learning to Produce Novel Foreign Phonemes.

Learning to pronounce a foreign phoneme requires an individual to acquire a motor program that enables the reproduction of the new acoustic target sound. This process is largely based on the use of auditory feedback to detect pronunciation errors to adjust vocalization. While early auditory evoked neural activity underlies automatic detection and adaptation to vocalization errors, little is known about the neural correlates of acquiring novel speech targets. To investigate the neural processes that mediate the learning of foreign phoneme pronunciation, we recorded event-related potentials when participants (N = 19) pronounced native or foreign phonemes. Behavioral results indicated that the participants' pronunciation of the foreign phoneme improved during the experiment. Early auditory responses (N1 and P2 waves, approximately 85-290 ms after the sound onset) revealed no differences between foreign and native phonemes. In contrast, the amplitude of the frontocentrally distributed late slow wave (LSW, 320-440 ms) was modulated by the pronunciation of the foreign phonemes, and the effect changed during the experiment, paralleling the improvement in pronunciation. These results suggest that the LSW may reflect higher-order monitoring processes that signal successful pronunciation and help learn novel phonemes.