Interpeak Latencies Research Articles

Pain-Related Vertex Evoked Potentials. Comparison of Surface Electrical to Heat Stimulation.

Demonstration of nociceptive fiber abnormality is important for diagnosing neuropathic pain and small fiber neuropathies. This is usually assessed by brief heat pulses using lasers, contact heat, or special electrodes. We hypothesized that pain-related evoked potentials to conventional surface electrical stimulation (PREPse) can index Aδ afferences despite tactile Aß fibers coactivation. PREPse may be more readily used clinically than contact heat evoked potentials (CHEPS). Twenty-eight healthy subjects. Vertex (Cz-A1/A2) recordings. Electrical stimulation of middle finger and second toe with conventional ring, and forearm/leg skin with cup, electrodes. Contact heat stimulation to forearm and leg. Compression ischemic nerve blockade. PREPse peripheral velocities were within the midrange of Aδ fibers. N1-P1 amplitude increased with pain numerical rating scale graded (0-10) electrical stimulation (n = 25) and decreased with increasing stimulation frequency. Amplitudes were unchanged by different presentation orders of four stimulation intensities. PREPse N1 (∼130 milliseconds) and N2 (∼345 milliseconds) peaks were approximately 40 milliseconds earlier than that with CHEPS. PREPse and CHEPS N1-N2 interpeak latency (∼207 milliseconds) were similar. PREPse became unrecordable with nerve blockade of Aδ fibers. PREPse earlier N1 and N2 peaks, and similar interpeak N1-N2 latencies and central conduction velocities, or synaptic delays, to CHEPS are consistent with direct stimulation of Aδ fibers. The relation of vertex PREPse amplitude and pain, or the differential effects of frequency stimulation, is similar to pain-related evoked potential to laser, special electrodes, or contact heat stimulation. The relationship to Aδ was validated by conduction velocity and nerve block. Clinical utility of PREPse compared with CHEPS needs validation in somatosensory pathways lesions.

Effect of General Anesthesia on Auditory Brainstem Response Testing.

Objective:The auditory brainstem response (ABR) test is usually applied during natural sleep, but it can also be conducted under anesthesia. This retrospective study aimed to compare the ABR findings of a general anesthesia group and a control group that underwent ABR test during natural sleep.Methods:The anesthesia group consisted of 42 (mean age 44.5±20.3 months) children, and the control group included 58 children (36.1±16.1 months). The results of the click ABR test of the two groups were compared in terms of amplitude, latency, interpeak latencies, and hearing thresholds.Results:The amplitudes of waves III and V were significantly decreased in the general anesthesia group compared with that in the control group. The ABR latencies of waves I and V and the interpeak latencies for I-V and III-V were prolonged in the anesthesia group compared with that in the control group. Moreover, the click threshold obtained in the anesthesia group was significantly higher than those of the control group.Conclusions:Clinicians and audiologists should advise families to know the effects of general anesthesia on ABR and be cautious in interpreting the results obtained in ABR test performed under anesthesia.

Aging process and central auditory pathway: a study based on auditory brainstem evoked potential and frequency-following response.

ABSTRACTObjective To analyze age-related changes in the central auditory pathway in healthy elderly individuals.Methods A prospective, quantitative cross-sectional study. The caseload comprised 18 adults (mean age, 22.78 years) and 18 elderly individuals (mean age, 66.72 years) of both sexes, who met inclusion criteria. Subjects were submitted to basic audiological evaluation and related electrophysiologic tests: brainstem auditory evoked potential with click stimulus and frequency-following response.Results Elderly individuals had higher wave and interpeak latencies (waves I, III and V and interpeaks I-V and III-V) of brainstem auditory evoked potential. Latencies of frequency following response waves A, E, F and O were also higher in elderly individuals. Frequency following response amplitudes were better in A than in D, F and O waves in these subjects. Likewise, interpeak intervals (V-A and V-O) were larger in elderly relative to adult individuals. Lower slope values were observed in elderly individuals.Conclusion Brainstem auditory evoked potential and frequency-following response allowed appropriate assessment of age-related changes in the auditory pathway. Slower neural response to auditory stimuli suggests reduced synchrony between neural structures.

Does glutaric aciduria type 1 affect hearing function?

This study aimed to evaluate audiological findings among patients with glutaric aciduria type 1 (GA-1). We used a large test battery for the audiological evaluation of 17 individuals with GA-1 (the study group) and 20 healthy individuals (the control group). Conventional audiometry (0.125-8kHz), distortion product otoacoustic emissions (DPOAEs) (1, 1.5, 2, 3, 4, 6, and 8kHz), contralateral suppression of otoacoustic emissions, and auditory brainstem response (ABR) ( 30, 50, 70 and 90 dB nHL) were measured for all participants (n = 37). Mild sensorineural hearing loss was found in 77.47% (n = 13) of the patients with GA-1, and normal hearing thresholds were seen in 23.53% (n = 4). There were three asymptomatic patients at the time of diagnosis [two developed mild mental motor retardation (MMR) and one developed severe MMR during the follow-up], one with a normal hearing threshold and two with mild hearing loss), and 14 symptomatic patients (three with normal hearing thresholds and 11 with mild hearing loss). Seven of the symptomatic patients diagnosed following an encephalopathic crisis required intensive care and showed significantly worse hearing thresholds than those without symptoms [20.86 ± 4.47 vs. 15.44 ± 3.96 decibel hearing level (dB HL), p = 0.039*], while five had mild-to-moderate hearing loss. Acute encephalopathic crisis had a negative effect on hearing function in the symptomatic patients. The emission and contralateral suppression amplitude values of the study group were significantly lower compared to the control group (p < 0.05). The I-V interpeak latency and absolute latencies of ABR waves I, III, and V of the study group were observed to be significantly prolonged and morphologically distorted compared to those of the control group (p < 0.05). Five patients had MMR, and three had moderate MMR; all eight had mild-to-moderate hearing loss. In addition, of the eight patients with mild MMR, four had mild hearing loss. In particular, the morphological findings of ABR waves were significantly worse in the patients with severe and moderate MMR (p < 0.05). There was a significant correlation between a macrocephaly history (12 patients) and hearing loss (p = 0.041*). Magnetic resonance imaging findings were evaluated in all the 17 patients with GA-1, and typical fronto-temporal atrophy and sylvian fissure enlargement were observed. Our findings support that GA-1 is associated with auditory impairment, primarily in symptomatic patients. Adequate audiological test battery evaluation is essential in this context, particularly for symptomatic patients with a history of encephalopathic crises.

Audiological findings in individuals diagnosed with COVID-19

PurposeIt is thought that COVID-19 may cause hearing loss, but its effects on the hearing system are not clear. This study aimed to reveal the effects of COVID-19 on the auditory system by using various audiological measurement methods in individuals diagnosed with COVID-19. MethodsThirty individuals between the ages of 18–45, who were diagnosed with COVID-19 by PCR at least one month ago, and had no pre-COVID-19 hearing loss complaints, constituted the test group. Thirty individuals aged between 18 and 30 years and who had no history of hearing loss constituted the control group. Audiological evaluations of all participants were made with pure-tone audiometry, high-frequency audiometry, transient-evoked otoacoustic emission (TEOAE), distortion product otoacoustic emission (DPOAE), and auditory brainstem response (ABR) measurements. ResultsA significant difference was found between the groups at all high frequencies between 4 and 14 kHz (p < 0.05). TEOAE amplitudes at 1500 Hz, 2000 Hz and 4000 Hz frequencies and DPOAE amplitudes at 4003 Hz and higher frequencies were significantly lower in the test group (p < 0.05). While there was a significant difference between the I, III and V absolute latencies between the groups (p < 0.05), there was no significant difference between the I-III, III-V and I-V interpeak latencies (p > 0.05) as a result of the ABR test. ConclusionThis study showed that COVID-19 can cause cochlear damage, especially at high frequencies. More studies are needed to determine the effects of COVID-19 on the auditory system.

Application of ABR in pathogenic neurovascular compression of the 8th cranial nerve in vestibular paroxysmia

PurposeTo investigate the clinical value of electrophysiological tests in indicating pathogenic vascular contact of the 8th nerve in definite vestibular paroxysmia (VP) cases to provide a reference for decompression surgery.MethodsWe retrospectively analyzed patients who had vertigo, unilateral tinnitus, or hearing loss and exhibited vascular contact of the 8th cranial nerve by MRI. Participants were classified into the VP or non-VP group according to the criteria of the Bárány Society in 2016. The demographic characteristics and audiological and electrophysiological test results of the two groups were compared. Receiver operating characteristic (ROC) curves were calculated for ABR to determine the best parameters and cutoff values to predict the existence of pathological neurovascular contact in VP.ResultsThirteen patients in the VP group and 66 patients in the non-VP group were included. VP patients had longer interpeak latency (IPL) I–III and wave III latency compared to non-VP patients (p < 0.001; p < 0.001). According to the ROC analyses, IPL I–III and wave III latency were the best indicators for the diagnosis of VP. The optimal cutoff for IPL I–III was 2.3 ms (sensitivity 84.6%, specificity 95.5%), and that for wave III latency was 4.0 ms (sensitivity 92.3%, specificity 77.3%). There were no differences in the PTA, caloric test, o-VEMP, or c-VEMP results between the two groups.ConclusionProlonged IPL I–III and the wave III latency of ABR strongly suggested that vascular contact of the 8th cranial nerve was pathological, which may provide some references for microvascular decompression surgery of VP.

Brainstem auditory evoked potential in cognitive impairment in patients with type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) can cause mild cognitive impairment (MCI) which threatens the health of patients. So the diagnosis of MCI is particularly important. It is reported that brainstem auditory evoked potential (BAEP) is a sensitive tool to detect the brainstem function in patients with T2DM. This study aimed to investigate the relationship between BAEP and MCI in patients with T2DM. A total of 244 T2DM patients with normal hearing, including 117 normal cognition patients and 127 MCI patients, were recruited in this cross-sectional study. Each subject underwent the BAEP examination. The diagnosis of MCI was based on the diagnostic guideline developed by the National Institute on Aging-Alzheimer's Association workgroups. The Montreal Cognitive Assessment (MoCA) was used to assess the cognitive function of the subjects. Compared with the normal cognition group, the patients in the MCI group had longer latencies of waves III and V and interpeak latencies (IPL) I-V in both ears (P<0.05). The significant negative correlations were found between the latencies of waves III, V, IPL I-V, and MoCA score in both ears (P<0.05). Logistic regression showed that the prolongations of latunits of waves III and V and IPL I-V in both ears were still associated with MCI after adjustment for mixed factors (P<0.05). These results indicate abnormal auditory pathway in brainstem of T2DM patients with MCI. BAEP may contribute to the clinical diagnosis of MCI in patients with T2DM.

Uneven Effects of Sleep Apnea on Semicircular Canals and Otolithic Organs.

ObjectiveThis study aimed to explore how obstructive sleep apnea (OSA) affects the function of each vestibular organ and to identify the correlations among them.MethodsA prospective study was conducted involving 32 healthy controls and 64 patients with OSA. The objective detection methods of the utricle and saccule are vestibular-evoked myogenic potentials (VEMPs). A combination of the caloric test and video head impulse test (vHIT) was used to comprehensively evaluate the objective function of semicircular canals.ResultsElevated thresholds (p < 0.001), decreased waveform amplitudes (p < 0.001), prolonged first wave latencies (p < 0.001), and shortened first interpeak latencies (p < 0.001) were observed in both ocular VEMP (oVEMP) and cervical VEMP (cVEMP). A significant difference was found in the caloric test comparison (χ2 = 4.030, p = 0.045) but not in the vHIT. The intergroup comparison of normal rates among the VEMPs, caloric test, and vHIT groups showed a significant difference (p < 0.001).ConclusionThe impairment of vestibular function in patients with OSA was uneven and biased. More attention should be given to vestibular dysfunction in the diagnosis and treatment of OSA.

STUDY OF BRAINSTEM EVOKED AUDITORY RESPONSE IN TYPE 2 DIABETICS WITH NORMALAND ELEVATED BODY MASS INDEX

Background: Diabetes mellitus is a metabolic syndrome affecting many organs including the heart, kidneys, eyes and nerves Aim: The study aims to understand the changes in brain stem evoked auditory response(BERA) in type 2 diabetics with normal and elevated Body mass index. Materials And Methods: 60 individuals diagnosed with type 2 diabetes belonging to age group 30 - 50 years having normal and elevated BMI (Body Mass Index) were studied. Their Brainstem evoked auditory response was recorded and results were studied with the help of unpaired t test. The brainstem evoked auditory response(BERA) wave latencies I, II, III, IV, V and interpeak latencies I-III, III-V, I-V were recorded individually for left and right ear. Result: Signicant increase in latencies of waves I, III, V and interpeak latencies I-III, III-V, I-V were observed in diabetics with elevated BMI when compared with normal BMI. There was a positive association seen between BMI and wave latencies I, III,V and interpeak latencies I-III, III-V, I-Vwere also observed. Conclusion: The study shows that type2 diabetic patients with elevated BMI can have subclinical hearing loss and impaired brainstem evoked auditory response. BERA is a simple non-invasive tool in early diagnosis. So management of diabetes along with maintaining ideal Body mass index will help in preventing early sensory neural hearing loss.

Auditory brainstem response in unilateral tinnitus patients: does symmetrical hearing thresholds and within-subject comparison affect responses?

In recent studies, cochlear synaptopathy has been suggested as a potential pathophysiology mechanism for tinnitus, which occurs in individuals with normal hearing thresholds. Auditory Brainstem Response (ABR) is a noninvasive method frequently used in the literature to evaluate cochlear synaptopathy in tinnitus patients. However, possible factors such as high-frequency pure-tone hearing thresholds, age, gender, and head characteristics that may affect ABR were not considered sufficiently in previous studies. Therefore, the present study aims to evaluate tinnitus ears and non-tinnitus ears with ABR in unilateral chronic tinnitus patients with symmetrical hearing. Twenty unilateral chronic tinnitus patients having normal pure-tone average with symmetrical hearing thresholds was included in the study. Subjects were evaluated with 0.25-16kHz pure-tone audiometry, Tinnitus Handicap Inventory (THI) and ABR were administered. All ears were evaluated monaurally using click stimuli at 80dB nHL, alternating polarity (21.1 rate/s, 2000 sweeps). Wave I amplitude of the ABR and the ratio of III/I, V/I, and V/III wave amplitudes from tinnitus ears was higher than non-tinnitus ears. At the same time, there was a positive correlation between THI and V-I and V-III interpeak latency range, and a negative correlation between V/III wave amplitude ratio. ABR can be used as an evaluation method to provide evidence that the neural organizations of individuals with chronic tinnitus differ in certain regions in their auditory pathways. The correlation between THI and ABR findings suggests that there may be a connection between tinnitus distress and the neural organization of the auditory system.

Evaluation of vestibular-evoked myogenic potential for functional integrity of the brain stem in Kennedy's disease

Objective: To investigate whether vestibular-evoked myogenic potentials(VEMPs) can be used to assess brainstem involvement in patients with Kennedy's disease (KD). Method: This was a case-control study.Twenty consecutive patients with genetically confirmed KD and 20 age-and sex-matched healthy subjects were enrolled from November 2018 to September 2020.All subjects were tested for three types of VEMPs, including cervical VEMP (c-VEMP) recorded by the sternocleidomastoid muscle (parameter:p13, n23), masseter VEMP (m-VEMP) recorded by the masseter muscle(parameter: p11), and ocular VEMP (o-VEMP) recorded by the inferior oblique muscle (parameter n10, p15).The latency of each wave, interside peak latency and interpeak latency of c-VEMP, the corrected amplitude and amplitude asymmetry ratio were recorded. Bilateral sternocleidomastoid muscle (SCMM) electromyography (EMG) was performed. The spinal cord and bulbous muscular atrophy functional rating scale (SBMAFRS) was used for assessment. Results: The mean p13 latency of c-VEMP was (15.5±1.4)ms, which was longer than that of the control group[(13.3±0.9)ms](P<0.05); the mean n23 latency was(25.5±1.4)ms, which was also longer than that of the control group[(22.5±1.0)ms] (P<0.05); the difference of bilateral p13[(2.3±0.6)ms] was significantly higher than that of the control group(P<0.05). The abnormal rates of c-, m-, o-VEMP in KD patients were 75%(15/20), 30%(6/20) and 20%(4/20), respectively. There was a significant positive correlation between c-VEMP latency and course of disease in KD patients(left: r=0.715, 0.695, right: r= 0.708, 0.715, both P<0.05). However, c-VEMP latency was negatively correlated with SBMAFRS score (left: r=-0.701, -0.694, right: r=-0.644, -0.685, both P<0.05). Abnormal rates of SCMM EMG in KD group were as follows: 15%(3/20)of patients showed spontaneous potential in resting state and 45% (9/20) of patients exhibited simple recruitment. Conclusions: The c-VEMP latency is a sensitive tool for detecting lower brainstem involvement in patients with KD, and the degree of damage increases with prolongation of disease course. The o-and m-VEMP abnormalities indicate that some KD patients develop upper brainstem damage.

Effect of Maternal Age and Anaemia on Auditory Brainstem Response of Preterm Infants in a Tertiary Care Hospital of Kolkata, West Bengal: A Cross-sectional Study

Introduction: Adolescent pregnancy and maternal anaemia have a detrimental effect on infant growth and development. They are associated with greater risk of premature births and Low Birth Weight (LBW). Wave Interpeak Latencies (IPLs) of infant Auditory Brainstem Response (ABR) indicate the degree of maturation of brainstem auditory pathways among preterm infants. Previous studies indicated that preterm infants show prolonged wave Interpeak Latencies (IPLs). Whether maternal parameters like age and haemoglobin level contributes to the changes in infant ABR is debated. Aim: To study the effect of maternal age and anaemic status on Brainstem Evoked Response Audiometry (BERA) changes among preterm infants. Materials and Methods: An observational, descriptive study of cross-sectional design was undertaken in the Neurophysiology laboratory of Department of Physiology, RG Kar Medical College and Hospital, Kolkata from December 2019 to December 2022. Total of 119 mother-preterm infant dyads were included. Click BERA was performed on the babies aged between 3 months to 1 year. Absolute and IPLs of wave I,III and V were obtained. Mothers were assigned anaemic status {Haempglobin (Hb) level&lt;9gm/dL} based on the information in their antenatal card. Student’s t test, Fisher’s exact test, one way ANOVA test were used for data analysis. A p-value less than 0.05 was considered significant. Results: Out of 76 adolescent mothers (age between 10 to &lt;18 years), 43 (56.6%) were anaemic. Out of 43 adult mothers (with age ≥18 years), 33 (76.7%) were anaemic. Mothers were divided into four groups, namely adolescent anaemic (n=43) and adolescent non anaemic (n=33), adult anaemic (n=33) and adult non anaemic (n=10). Distribution of data with respect to education years, social class and occupation among four mothers’ group was comparable [p-value&gt;0.05]. Preterm infants born to both anaemic adult [Hedges g=2.51] and anaemic adolescent mothers [Hedges g=1.06] showed dyssynchronous shortening of wave latencies compared to non anaemic counterparts (p-value&lt;0.05). Magnitude of difference with respect to infant ABR for non anaemic adolescent mothers vs non anaemic adult counterparts was large [Hedge s g=1.05] with p-value&lt;0.05. While maternal anaemia showed either shortening or prolongation of IPLs, adolescent maternal age was related with prolongation of the wave I-V. Effect size of maternal anaemia on infant ABR was more than for adolescent maternal age. Conclusion: Maternal anaemia may exaggerate abnormal maturation of the brain stem pathways in preterm infants irrespective of maternal age.

Normative data for brainstem auditory evoked potential responses in North Indian menopausal females

Background: Ovarian hormones are known to influence central neuronal functioning. Many studies have established the brainstem auditory evoked potential (BAEP) pattern vis-à -vis the cyclical fluctuations of these hormones in young females; however, there is a paucity of research involving BAEP patterns among menopausal females. Aim: This study was conducted to provide normative values for various BAEP parameters in menopausal females from North India. Materials and Methods: A cross-sectional study was done on 100 females aged 46–70 years. BAEP recording was done using a standardized protocol. The data were analyzed using SPSS software. It consisted of mean wave latencies I, II, III, IV, and V and interpeak latencies (IPL) I-V, I-III, and III-V. Student's unpaired t-test was used for statistical analysis. Results: The average value of means of wave latencies and IPL from both the ears was obtained. The latencies of waves I, II, III, IV, and V were 1.82 ± 0.27 ms, 2.81 ± 0.27 ms, 4.09 ± 0.35 ms, 4.87 ± 0.33 ms, and 6.19 ± 0.31 ms, respectively. The mean values of IPL I-V, I-III, and III-V were 4.37 ± 0.38 ms, 2.26 ± 0.33 ms, and 2.1 ± 0.32 ms, respectively. Conclusion: The study findings compared favorably with already existing data from similar studies conducted elsewhere. The data from the present study would prove useful to the clinicians to detect subtle neurodegenerative changes at an early stage within the central auditory pathways, even in the absence of any perceptible hearing loss, in this subset of population.

Detrimental Effects of Traffic Noise in Traffic Policemen as Assessed by Auditory Brainstem Evoked Response: A Cross-sectional Observational Study

Introduction: Loud noise is a global occupational health hazard with substantial social and physiological impacts, especially pronounced in traffic policemen who are engaged at heavy traffic junctions. Apart from its overt effect on sensorineural hearing, loud noise has been also implicated, albeit covertly, as a causative factor for disturbances in sleep, learning and depression. Due to the insidious nature of hearing impairment, manifestations are often masked and hence testing through Auditory Brainstem Evoked Response (ABER) should be resorted to, for assessment of functional status of auditory pathway objectively. Aim: To assess and compare the effect of traffic noise in traffic policemen with age matched apparently healthy males using ABER. Materials and Methods: The present study was a crosssectional, comparative type of observational research conducted in the Department of Physiology, SMS Medical College, Jaipur, Rajasthan, India, from June 2019 to May 2020, on 45 apparently healthy male traffic policemen, aged 25-40 years, engaged at heavy traffic junctions of Jaipur city, with an average field posting of five years or more. An equal number of age and sex matched apparently healthy subjects living in Jaipur city, were recruited as controls. Before commencing with the test procedure, ethical clearance was obtained from the institute’s ethics committee and research review board and written informed consent was obtained from all the participants. ABER assessment was done via RMS EMG SALUS 2C machine on each subject using click stimuli presented mono-aurally via an overhead headphone resulting in harvest of variables in form of absolute wave latencies (I to V) and Interpeak Latencies (IPL) (I-III, I-V and III-V). Unpaired Student’s t-test was used to derive the level of significance using Statistical Package for the Social Sciences (SPSS) version 16.0. Level of significance was set at p-value &lt;0.05. Results: The results obtained in the present study demonstrated pronounced delay (p-value&lt;0.01) in all absolute wave latencies (I to V) in both ears in traffic policemen. A statistically significant delay was also observed in IPL I-V (p-value&lt;0.01) when a comparison of left ABER was made between traffic policemen and controls. Conclusion: The findings of the present study indicate that the hidden footprints of loss in auditory acuity in traffic policemen exposed to traffic noise can be unearthed objectively via using ABER assessment and therefore periodic ABER assessment along with usage of preventive equipment should be the strategy for prevention of imminent hearing loss.

Auditory brainstem response for Sri Lankan children under 5 years of age: Normativedata

For years Sri Lankan Audiologists resorted to western norms in the interpretation of Auditory Brainstem Response (ABR) in the absence of national standards. The study focused on establishing normative data on ABR for Sri Lankan children below 5 years. ABR was performed on 258 healthy children between 6 weeks and 5 years of age to gather data on absolute latencies and inter-peak latencies.All inter-aural differences were within 0.2-0.4ms. The mean inter-aural difference for the study sample was significantly small (-0.0204ms to 0.0286ms). Mean values of absolute latencies for waves I, III, V for the 6-week age group at 30dBnHL were 3.33 ms, 5.91 ms and 8.27 ms respectively. Mean values of inter-peak latencies of wave I-III, III-V, I-V were 2.08 ms, 2.36 ms and 4.76 ms respectively for the 6-week age group at 30 dBnHL. The normative ABR data obtained in this study may be used across audiology clinics in Sri Lanka as a baseline measurement to diagnose hearing loss among children from infancy to 5 years of age when children are tested in their natural sleep and insert earphones are used. The mean value plus 2 standard deviations for each ABR measure may be used as the upper limit cutoff values. Hence this study helps eliminate misdiagnosis and under-diagnosis of hearing loss in children.

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.

Effects of neurodevelopmental risk factors on brainstem maturation in premature infants.

Interpeak latencies (IPL), as measured by the auditory brainstem-evoked responses (ABR) test, represent the conduction time, and therefore the maturation of the brainstem auditory pathway. We aimed to study the effect of various risk factors for the neurodevelopmental delay on the conduction time in the auditory pathway among normal hearing premature infants, at term postmenstrual age (PMA). Retrospective analysis of 239 premature infants (gestational age 32.5 ± 2.1 weeks, birth weight 1827 ± 483 g). Interpeak latencies, demographic data, and risk factors were recorded. Sex, PMA at ABR test, being small for gestational age (SGA), intraventricular hemorrhage (IVH) or periventricular leukomalacia (PVL), and days of invasive ventilation were found to significantly affect the IPL's in the auditory pathway in a univariate analysis. Multivariable regression analysis revealed that male sex and less advanced PMA at the examination were independent factors associated with prolonged IPL's, while bronchopulmonary dysplasia, IVH or PVL and being SGA shortened the IPL's. Non-invasive mechanical ventilation, did not affect the caudal part of the auditory pathway, despite its high noise level. Among various risk factors for the neurodevelopmental delay, male sex was associated with delayed, while IVH or PVL, BPD and SGA could be associated with accelerated auditory brainstem maturation. Auditory brainstem-evoked response (ABR) test, among normal hearing infants, can serve as a clinical tool to assess brainstem auditory maturation. Different neurodevelopmental risk factors could have different effects on the maturity of the auditory pathway. Male sex is significantly associated with prolonged interpeak latencies (IPL) among preterm and term infants, while intraventricular hemorrhage or periventricular leukomalacia, bronchopulmonary dysplasia, and being small for gestation age may be associated with shortened IPL The corrected age at ABR testing is of significance, among preterm and term infants.

Diagnostic Validity of Auditory Brainstem Response for the Initial Screening of Vestibular Schwannoma.

Background and ObjectivesTo investigate the diagnostic validity of auditory brainstem response (ABR) in the screening of vestibular schwannoma (VS).Subjects and MethodsForty patients diagnosed with VS using magnetic resonance imaging who had undergone ABR before treatment between 2005 and 2015 were included. ABR results were considered positive when findings met at least one of the following criteria: 1) absent evoked response, 2) desynchronization of waves other than wave I, 3) interpeak latency (IPL) between waves I and III >2.5 ms, 4) IPL between waves I and V >4.4 ms, 5) wave V interaural latency difference >0.2 ms, and 6) interaural difference in IPL between waves I and V >0.2 ms.ResultsThe overall sensitivity of ABR was 85.0%. For tumors measuring <10 mm, the sensitivity of ABR was 66.7%, whereas it increased to 90.3% for tumors measuring >10 mm. The sensitivity of tumors confined to the internal acoustic canal was 73.3% compared with 100.0% for tumors confined to the cerebellopontine angle. In patients with serviceable hearing, the mean tumor size was 7.8±2.9 mm in patients with a normal ABR and 15.1±9.4 mm in patients with an abnormal ABR, indicating a significant difference (p<0.05).ConclusionsABR alone is insufficient for the screening of VS, bearing the risk of false-negative outcomes when examining small, intracanalicular tumors. However, ABR can be inexpensively applied for the screening of VS measuring >10 mm in patients with serviceable hearing, supporting the need for further active diagnostic and treatment modalities in clinical practice.

Analysis and comparison of a spinal cord injury model with a single-axle-lever clip or a parallel-moving clip compression in rats.

Experimental animal study. To assess the feasibility of a custom-designed parallel-moving (PM) clip, compared with a single-axle-lever (SAL) clip, for the development of a compressional spinal cord injury (SCI) model in rats. Hospital laboratory in China. We used a PM clip and a SAL clip with same compression rate, to develop a SCI model in rats, and set a sham group as a blank control. Within 3 weeks, each group of rats was evaluated for behavioral (Basso-Beattie-Bresnahan locomotor rating score, BBB), and electrophysiological changes (somatosensory evoked potential), and historical staining to observe the differences between the three groups. In particular, the mechanical results of the PM group were calculated. The BBB scores for the SAL and PM groups were significantly lower than those for the sham group (P < 0.05), no significant difference between the two methods (P > 0.05), but the values corresponding to the PM group had smaller standard deviations. The interpeak-latency (IPL) was significantly prolonged (P < 0.0001) and the peak-peak amplitude (PPA) was significantly reduced (P < 0.01) in SAL and PM groups than those in the sham group, but there was no statistical difference in both IPL and PPA between the two SCI groups (P > 0.05). Histological staining showed obvious pathological changes in two SCI groups, and the shape of the lesion zone in the PM group was more symmetrical than that in the SAL groups. The use of a compressional SCI model in rats with the PM clip we designed is an appropriate method to quantify the injury. The degree of the injury caused by this clip is more stable and uniform than those with classical methods.

Ωto_abR: A Web Application for the Visualization and Analysis of Click-Evoked Auditory Brainstem Responses

Since its inception by Jewett and Williston in the late 1960s, the auditory brainstem response (ABR) has been an indispensable diagnostic tool, used by audiologists around the world. Click-evoked ABR testing proves to be a reliable tool, as it provides an objective representation of the auditory function, an estimate of hearing thresholds and the ability to pinpoint a potential issue in the auditory neural pathway. The present study describes state-of-the-art ABR analytics-related platforms and provides an overview of their functionality. In conjunction, we introduce the design and development of a newly developed, user-friendly web application, built in R language. This application provides several well-known and newly key characteristics for the analysis of ABR waveforms. These include absolute peak latencies, amplitudes, and interpeak latencies.