Absolute Latencies Research Articles

Effects of Hyperbilirubinemia on Auditory Brainstem Response of Neonates Treated with Phototherapy.

One of the most common pathologies in neonates is hyperbilirubinemia, which is a good marker for damage to the central nervous system. The sensitivity of the auditory system to bilirubin has been previously documented, with much discrepancy in its effects on Auditory Brainstem Response results. Thus the objective of this study was to evaluate the effects of hyperbilirubinemia on Auditory Brainstem Response of neonates treated with phototherapy. Forty-two term neonates with hyperbilirubinemia, who underwent phototherapy participated in this cross sectional study. The recording of Auditory Brainstem Response was made shortly after confirming that the total serum bilirubin level was greater than 15 µg/dl. Latency of waves I, III, V and inter-peak latencies of the waves were measured. To test the hypothesis about the difference of means between the two groups, continuous variables were compared using either the t-test (normal distribution) or the Mann-Whitney test (non-normal distribution). There was a significant increase in the absolute latencies of waves III and V, and I-III and I-V inter-peak latencies of the sample group compared to the control group in both ears (P<0.05). However, wave I absolute latency and III-V inter-peak interval did not show a significant difference between the two study groups (P>0.05). The results of this study underline the importance of the Auditory Brainstem Response Test as an efficient tool for monitoring the auditory brainstem pathway in neonates who are at risk of neurotoxicity and for diagnosing the earliest stages of auditory damage caused by high levels of bilirubin.

To Study Brain Stem Auditory Evoked Potential in Patients with Type 2 Diabetes Mellitus- A Cross- Sectional Comparative Study.

Neuropathy is one of the commonest complications of Diabetes Mellitus (DM). Apart from having peripheral and autonomic neuropathy patients with type 2 DM may also suffer from sensory neural hearing loss, which is more severe at higher frequencies. However, few studies have done detailed evaluation of sensory pathway in these patients. In this study brain stem auditory evoked potential is used to detect the acoustic and central neuropathy in a group of patients with type 2 DM with controlled and uncontrolled blood sugar. To study brain stem auditory evoked potential in patients of type 2 DM with controlled and uncontrolled blood sugar and to correlate the various parameters e.g., age (years), weight (kilograms), height (meters), BMI (kg/m2), HbA1c (%) in patients with type 2 DM with controlled and uncontrolled blood sugar. Cross-sectional comparative study conducted from January 2014 to January 2015. Total 60 patients with type 2 DM of either sex, between age groups of 35-50 years were enrolled from the Diabetic Clinic of Medicine department, of a tertiary care hospital. Based on the value of HbA1c, patients were divided in two groups with controlled and uncontrolled blood sugar and with each group comprising of 30 patients. BERA (Brainstem Evoked Response Audiometry) was done in both the groups on RMS ALERON 201/401. Recordings were taken at 70dB, 80dB and 90dB at 2KHz frequency. Absolute latency of wave I, III, V and interpeak latencies I-III, III-V and I-V were recorded. Mean±SD of the absolute latency of BERA waves I, III, V and interpeak latencies I-III, III-V and I-V at 2 KHz and at varying intensity of 70dB, 80dB and 90dB in uncontrolled group of DM were delayed and were significant as compared to controlled group of DM. If BERA is done in diabetic patients, central neuropathy can be detected earlier in uncontrolled groups of diabetic patients.

Impact of controlling hypothyroidism on auditory dysfunction

Background Hypothyroidism is defined as deficient thyroidal hormone production, and may be congenital or acquired. Aim The aim of the study was to determine the presence of auditory disorder in a group of Egyptian women with hypothyroidism and to detect the effect of medical treatment of hypothyroidism on auditory function. Patients and methods Forty hypothyroid women, their ages ranging from 30 to 60 years, were divided into two groups: group 1 (recently diagnosed group), which consisted of 20 drug-naive patients (this group was studied before and after treatment in the form of thyroid hormone replacement); and group 2, which consisted of 20 chronic patients out of medical control. All patients were submitted to history, full clinical examination, pure tone audiometry (PTA), immittancemetry, and auditory brainstem response. Results Sensorineural hearing loss was found among the hypothyroid patients of bilateral mild to moderate hearing loss. Statistically insignificant improvement of PTA threshold was present in the recently diagnosed group after treatment. There was a statistically significant improvement in absolute latencies of waves III and V and interpeak latencies of I–III and I–V in the recently hypothyroid post-treatment group. There were insignificant correlations between the levels of free thyroxin 4 and thyroid-stimulating hormone and auditory changes in hypothyroid patients. There was a statistically significant (positive) correlation between thyroid peroxides antibody and PTA threshold at 250, 500, 4000, and 8000 Hz for all studied groups. However, there was a statistically insignificant (positive) correlation between thyroid peroxides antibody and changes in auditory brainstem response. Conclusion The auditory changes in hypothyroid patients is reversible and may improve after treatment with thyroid replacement hormones (l-thyroxine).

Evaluation of otoacoustic emissions and auditory brainstem responses for hearing screening of high risk infants

Aim: The objective of the present study is the assessment of otoacoustic emissions (OAEs) and auditory brainstem responses (ABRs) for hearing screening of high risk infants. Study Design: Prospective, hospital-based. Materials and Methods: Distortion product OAEs (DPOAEs) and brainstem evoked response audiometry (BERA) recordings were obtained for 30 controls and 100 infants with one or more high risk factors, in a sound treated room and the results were interpreted. ABR peak latencies, amplitudes, and waveform morphology in high risk infants were compared with those in control group. DPOAE as screening test was evaluated in terms of various parameters with BERA/ABR taken as gold standard. Results: Absolute latencies of Wave I and Wave V and interpeak latency of I-V were significantly prolonged in high risk group as compared to control group. The most common causes to contribute significantly for hearing impairment were found to be hyperbilirubinemia, birth asphyxia, meningitis/septicemia. DPOAE when compared with ABR taken as gold standard showed that sensitivity of the test was 87.7% (74.5%-94.9%) and specificity was 74.5% (60.0%-85.2%). Positive predictive value was 76.7% (63.2%-86.6%) and negative predictive value of the test was 86% (71.9%-94.3%). Positive likelihood ratio was 0.29 (0.18-0.46) and negative likelihood ratio was 6.08 (2.82-13.09). Conclusion : ABR/BERA, though highly reliable, is a tedious and time consuming test. DPOAE is a simple and rapid test with relatively higher acceptability but low sensitivity and specificity; therefore, limits its role as independent screening test. DPOAE-ABR test series is an effective way to screen all the high risk infants at the earliest.

Auditory brainstem response and late latency response in individuals with tinnitus having normal hearing.

Tinnitus is a commonly encountered complaint in routine audiology practice. The pathophysiology and exact generation site of tinnitus is not precisely established. Auditory brainstem response (ABR) and late latency response (LLR) findings in individuals with tinnitus show mixed results in the literature. Majority of studies have focused on individuals having tinnitus with peripheral hearing loss. The present study explores ABR and LLR characteristics among tinnitus patients with normal audiometric presentation; with no direct indication of any cochlear lesion. This study aims at characterizing the ABR and LLR findings in individuals with tinnitus having normal audiometric presentation. ABR and LLR waveform characteristics were recorded and compared between participants with tinnitus (Group 1) and those without tinnitus (Group 2). The ABR analysis indicated no significant differences in latency and amplitude between Groups 1 and 2. However, patients with tinnitus showed abnormally reduced absolute amplitudes of peaks I and V. LLR analysis indicated no significant differences in latency and amplitude between Groups 1 and 2 except enhanced amplitude of P1. The reduced amplitude of peaks I and V along with normal absolute latencies of peaks I, III and V indicate that the origin of tinnitus is possibly due to reduced excitation of auditory nerve fibres arising from a peripheral hearing loss beyond 8 kHz. The P1 amplitude enhancement could be attributed to mechanism explaining central gain model; which suggests that central auditory structures recalibrates the mean firing rate, considering the reduced output from sensory structures, generating neural noise perceived as tinnitus.

Blink Reflex May Help Discriminate Alzheimer Disease From Vascular Dementia.

Dementia has several different etiologies, and vascular dementia (VaD) is considered the second leading cause of dementia after Alzheimer disease (AD). Various studies used blink reflex in different spectrum of neurological diseases as a complementary diagnostic test. We performed blink test in AD, VaD, and mixed dementia to investigate different usefulness of blink reflex in differentiating these types of dementia. Blink reflex was performed for patients with AD (n = 18), VaD (n = 17), mixed dementia (n = 19), and normal subjects (n = 20). The absolute latency of R1, R2, and contralateral R2 (R2c) was determined and then compared with normal values. We used ROC curve to determine the screening cut-off value for R2 and R2c to discriminate dementia with vascular component and AD. The mean age ± SD of patients was 71.61 ± 8.23, 66.71 ± 11.48, 75.26 ± 8.32, and 66.60 ± 3.91 years in 4 groups of AD, VaD, mixed dementia, and normal, respectively. R2 and R2c were recorded in fewer number of subjects with VaD or mixed dementia than AD and normal subjects. For mean R2 latency higher than 45 milliseconds, the sensitivity and specificity were 42% and 100%, respectively, and for latency higher than 45 milliseconds, the sensitivity and specificity were 72% and 89%, respectively. R2 and R2c components of blink reflex could specifically discriminate between Alzheimer and dementia with vascular component. The interruption of descending corticoreticular pathways by small infarcts could explain it.

Latent iron deficiency at birth influences auditory neural maturation in late preterm and term infants

In utero latent iron deficiency has been associated with abnormal neurodevelopmental outcomes during childhood. Its concomitant effect on auditory neural maturation has not been well studied in late preterm and term infants. The objective was to determine whether in utero iron status is associated with auditory neural maturation in late preterm and term infants. This prospective cohort study was performed at Sir Ganga Ram Hospital, New Delhi, India. Infants with a gestational age ≥34 wk were eligible unless they met the exclusion criteria: craniofacial anomalies, chromosomal disorders, hemolytic disease, multiple gestation, third-trimester maternal infection, chorioamnionitis, toxoplasmosis, other infections, rubella, cytomegalovirus infection, and herpes simplex virus infections (TORCH), Apgar score <5 at 5 min, sepsis, cord blood not collected, or auditory evaluation unable to be performed. Sixty consecutive infants with risk factors for iron deficiency, such as small for gestational age and maternal diabetes, and 30 without risk factors for iron deficiency were enrolled. Absolute wave latencies and interpeak latencies, evaluated by auditory brainstem response within 48 h after birth, were measured and compared between infants with latent iron deficiency (serum ferritin ≤75 ng/mL) and infants with normal iron status (serum ferritin >75 ng/mL) at birth. Twenty-three infants had latent iron deficiency. Infants with latent iron deficiency had significantly prolonged wave V latencies (7.10 ± 0.68 compared with 6.60 ± 0.66), III-V interpeak latencies (2.37 ± 0.64 compared with 2.07 ± 0.33), and I-V interpeak latencies (5.10 ± 0.57 compared with 4.72 ± 0.56) compared with infants with normal iron status (P < 0.05). This difference remained significant on regression analyses after control for confounders. No difference was noted between latencies I and III and interpeak latencies I-III. Latent iron deficiency is associated with abnormal auditory neural maturation in infants at ≥34 wk gestational age. This trial was registered at clinicaltrials.gov as NCT02503397.

Auditory Brainstem Evoked Response: response patterns of full-term and premature infants

Auditory Brainstem Response (ABR) is important for the early diagnosis of hearing impairment in infants.AimTo compare ABR responses in full-term and premature infants; gender and ear were taken into account.MethodsA cross-sectional prospective cohort study was carried out. We evaluated 36 full-term and 30 premature infants that had passed the Transient Otoacoustic Emissions test, had type A tympanometric curves, and had no risk factor for hearing loss besides prematurity. The evaluations were done from the time of hospital discharge to the third month of life, and consisted of a clinical history, acoustic immittance testing and ABR evaluation.ResultsThe comparison of absolute and interpeak wave I, III and V latencies in right and left ears revealed a statistically significant difference at the interpeak I-III. There was no significant gender differences in the comparison of results. Significant difference in wave I, III and V absolute latencies at 80 dB and in wave V at 60 db and 20 db were observed in a comparison of absolute and interpeak latencies between full-term and premature infants. An inverse correlation was found between age and absolute latencies.ConclusionsThe maturity of the auditory system influences ABR responses in infants. To avoid misinterpretation of results, gestational age must be taken into account in the analysis of ABR in pediatric population.

Prolonged auditory brainstem responses in infants with autism.

Numerous studies have attempted to identify early physiological abnormalities in infants and toddlers who later develop autism spectrum disorder (ASD). One potential measure of early neurophysiology is the auditory brainstem response (ABR), which has been reported to exhibit prolonged latencies in children with ASD. We examined whether prolonged ABR latencies appear in infancy, before the onset of ASD symptoms, and irrespective of hearing thresholds. To determine how early in development these differences appear, we retrospectively examined clinical ABR recordings of infants who were later diagnosed with ASD. Of the 118 children in the participant pool, 48 were excluded due to elevated ABR thresholds, genetic aberrations, or old testing age, leaving a sample of 70 children: 30 of which were tested at 0–3 months, and 40 were tested at toddlerhood (1.5–3.5 years). In the infant group, the ABR wave‐V was significantly prolonged in those who later developed ASD as compared with case‐matched controls (n = 30). Classification of infants who later developed ASD and case‐matched controls using this measure enabled accurate identification of ASD infants with 80% specificity and 70% sensitivity. In the group of toddlers with ASD, absolute and interpeak latencies were prolonged compared to clinical norms. Findings indicate that ABR latencies are significantly prolonged in infants who are later diagnosed with ASD irrespective of their hearing thresholds; suggesting that abnormal responses might be detected soon after birth. Further research is needed to determine if ABR might be a valid marker for ASD risk. Autism Res 2016, 9: 689–695. © 2015 The Authors Autism Research published by Wiley Periodicals, Inc. on behalf of International Society for Autism Research

Effect of otitis media with effusion on brainstem timing in children

Objective: Otitis media with effusion (OME) in early childhood may cause a central auditory processing disorder. The aim of the present study was to investigate the effect of prolonged OME in children on central auditory function using speech-ABR. Study design: Fifty-five children (31 males, 24 females) with bilateral OME were included in the present study. Their ages ranged from five to 11 years. According to the duration of the OME, the study group was divided into two groups: Group I (25 subjects with OME of long duration) and Group II (30 subjects with recent-onset OME). Responses to click evoked auditory brainstem response (click-ABR) and speech evoked auditory brainstem response (speech-ABR) were collected from the study groups I and II.Results: A Student's t-test revealed non-significant differences between groups I and II regarding different click-ABR parameters; absolute and interpeak latencies (I–III, III–V, and I–V). There were significant temporally delayed speech-ABR responses for the onset and offset of the stimulus (waves V, A and O), and reduction in VA slope in Group I compared to Group II. Conclusion: The findings suggest that OME of long duration in children is associated with deficient neural timing in response to the onset and offset of transient speech stimuli, resulting in a subtle impairment of speech encoding at the brainstem.

A Study of Brainstem Auditory Evoked Responses in Normal Hearing Patients with Tinnitus.

Tinnitus is thought to be an auditory phenomenon resulting from spontaneous neuronal activity somewhere along the auditory pathway either in the peripheral or central auditory system. The neural abnormalities underlying tinnitus are largely unknown. This study analysis the auditory brainstem responses in normal hearing patients with tinnitus. This study consisted of 100 patients divided into two groups. Group I (Control): 50 Normal hearing patients without tinnitus. Group II (Study): 50 Normal hearing patients complaining of tinnitus. Both groups were submitted to full audiological history taking, otological examination, basic audiologic evaluation and Auditory brainstem responses (ABR) followed by calculation of the absolute latencies of wave I, III and V and interpeak latencies between waves I-III, III-V and I-V. In the study group 20 patients showed abnormal results in at least 1 of the 6 parameters evaluated. The results of absolute latencies of wave I, III and V showed significant prolongation, but the interpeak latencies of waves I-III, III-V and I-V were not significantly prolonged when compared with control group. Our study data showed that there are changes in the central pathways in the study group. The significance of these changes must be investigated with further audiological and neurological tests. We also understand that ABR has to be included in the work up of tinnitus patients whose hearing is within normal parameters.

Alterations in brain-stem auditory evoked potentials among drug addicts. A cross-sectional study.

Objective:To compare the absolute latencies, the interpeak latencies, and amplitudes of different waveforms of brainstem auditory evoked potentials (BAEP) in different drug abusers and controls, and to identify early neurological damage in persons who abuse different drugs so that proper counseling and timely intervention can be undertaken.Methods:In this cross-sectional study, BAEP’s were assessed by a data acquisition and analysis system in 58 male drug abusers in the age group of 15-45 years as well as in 30 age matched healthy controls. The absolute peak latencies and the interpeak latencies of BAEP were analyzed by applying one way ANOVA and student t-test. The study was carried out at the GGS Medical College, Faridkot, Punjab, India between July 2012 and May 2013.Results:The difference in the absolute peak latencies and interpeak latencies of BAEP in the 2 groups was found to be statistically significant in both the ears (p<0.05). However, the difference in the amplitude ratio in both the ears was found to be statistically insignificant.Conclusion:Chronic intoxication by different drugs has been extensively associated with prolonged absolute peak latencies and interpeak latencies of BAEP in drug abusers reflecting an adverse effect of drug dependence on neural transmission in central auditory nerve pathways.

Auditory dysfunction in patients with type 2 diabetes mellitus with poor versus good glycemic control

Abstract Auditory functions among patients with type 2 diabetes mellitus (DM) are controversial regarding cochlear or neural changes and the relationship between these changes and serum level of glycosylated hemoglobin (HbA 1c%). The aim of the study was to investigate auditory dysfunctions in type 2 DM patients with poor versus good glycemic control. The present study was conducted on three groups: two diabetic groups with poor and good glycemic control (n = 18 and 14, respectively) based on serum HbA 1c% and one healthy control group (n = 30) matched with age, sex, and BMI. All participants were subjected to clinical assessment, audiometry, brainstem auditory evoked potential (BAEP), and evoked acoustic emissions transient evoked otoacoustic emissions and distortion product otoacoustic emissions (TEOAEs and DPOAEs). Diabetic patients with poor glycemic control had significantly elevated hearing thresholds compared with other groups at low and high frequencies in audiometry (P < 0.01 and P < 0.001). They showed significantly prolonged absolute latency in wave I and interpeak latency (III-V) in the BAEP test compared with other groups (P < 0.001). DM patients with poor glycemic control had significantly low amplitudes at all frequencies in the TEOAE test, as well as at high frequencies (4 and 6 kHz) on the DPOAE test, compared with other groups (P < 0.001 and P < 0.05, respectively). There were significant correlations between HbA 1c% and interpeak latency III-V (r = 0.340, P = 0.004) on the one hand and overall response of TEOAE amplitude (r = −0.471; P = 0.000) on the other. Diabetic patients with poor glycemic control had worse auditory dysfunctions on both cochlear and neural findings.

Auditory brainstem response in gerbils submitted to ischemia and sepsis.

An ischemic stroke is a clinical condition that affects thousands of people worldwide. As a result of this injury, neuronal death can be observed, and in the natural course of recovery, the individual may develop sepsis. Sepsis is a systemic inflammatory response that can lead the patient to death. To assess the clinical condition of a patient with this condition, the Auditory Brainstem Response (ABR) can be useful, since it is not an invasive procedure, it is a fast technique and it can be done at the bedside. To assess auditory brainstem response (ABR) latency values in gerbils subjected to ischemia and sepsis. ABR values were collected from 72 adult male gerbils, which were divided into six groups: control, sepsis, ischemia, sham, ischemia with sepsis, and sham with sepsis. For the induction of sepsis, lipopolysaccharide (LPS) was applied intraperitoneally in gerbils. The animals were anesthetized with a ketamine/xylazine combination before collection; their ABR were collected before any procedure (base collection), after ischemia, and 24 hours after the application of LPS. The absolute latency of wave IV was evaluated, and the values were compared between groups. There were significant differences in the groups submitted to sepsis in the latency value of wave IV in relation with the other groups. ABR was sensitive to sepsis with the increase in latency of wave IV during the development of the disease in the experimental model used.

Effect of Xylazine, Detomidine, and Detomidine–Butorphanol Combination on Latencies of Peaks I–V of Brainstem Auditory–Evoked Responses in Horses

Literature reports on the effect of sedative and anesthetic drugs on the first five peaks of brainstem auditory–evoked responses (BAERs) are somehow contradictory. In particular, no data are available on the effect of sedatives on BAER in horses. The objective of the study was to evaluate the influence of sedation with xylazine, detomidine, and detomidine–butorphanol combination on latencies of BAER peaks in horses. The absolute peak latencies of waves I, II, III, and V and interpeak latencies (IPLs) I–III, III–V, and I–V obtained in nine Bardigiano horses without sedation and with each of the sedation protocols were statistically compared. A statistically significant (P < .05) increase of the latency of wave III and of the IPL I–III was present in horses sedated with detomidine compared with the subjects not sedated or sedated with xylazine. An effect of detomidine on conduction time along the auditory pathway is suspected. These results must be taken into account when using α2-agonists with greater affinity for specific receptors, such as detomidine, for sedation of animals undergoing BAER for clinical or research purposes.

Continued maturation of the click-evoked auditory brainstem response in preschoolers.

Click-evoked auditory brainstem responses (ABRs) are a valuable tool for probing auditory system function and development. Although it has long been thought that the human auditory brainstem is fully mature by age 2 yr, recent evidence indicates a prolonged developmental trajectory. The purpose of this study was to determine the time course of ABR maturation in a preschool population and fill a gap in the knowledge of development. Using a cross-sectional design, we investigated the effect of age on absolute latencies, interwave latencies, and amplitudes (waves I, III, V) of the click-evoked ABR. A total of 71 preschoolers (ages 3.12-4.99 yr) participated in the study. All had normal peripheral auditory function and IQ. ABRs to a rarefaction click stimulus presented at 31/sec and 80 dB SPL (73 dB nHL) were recorded monaurally using clinically-standard recording and filtering procedures while the participant sat watching a movie. Absolute latencies, interwave latencies, and amplitudes were then correlated to age. Developmental changes were restricted to absolute latencies. Wave V latency decreased significantly with age, whereas wave I and III latencies remained stable, even in this restricted age range. The ABR does not remain static after age 2 yr, as seen by a systematic decrease in wave V latency between ages 3 and 5 yr. This finding suggests that the human brainstem has a continued developmental time course during the preschool years. Latency changes in the age 3-5 yr range should be considered when using ABRs as a metric of hearing health.

Brainstem Auditory Evoked Potentials in Boys with Autism: Still Searching for the Hidden Truth.

Brainstem auditory evoked potentials (BAEPs) have long been utilized in the investigation of auditory modulation and, more specifically, auditory brainstem functions in individuals with autism. Although most investigators have reported significant abnormalities, no single BAEPs pattern has yet been identified. The present study further delineates the BAEPs deficits among subjects with autism. BAEPs were recorded in 43 male patients, aged 35-104 months, who underwent standard evaluations after receiving a diagnosis of autism. The control group consisted of 43 age-matched typically developing boys. The study took place in a tertiary neurodevelopmental center over a period of two years. The mean values of all absolute and/or interpeak latencies were longer in patients when compared to controls, albeit the differences were not significant for any of the parameters. Prolonged or shortened absolute/interpeak latencies (control group mean ± 2.5SD) were unilaterally or bilaterally identified in 33% of patients, compared to 9% of controls. The most frequent findings included prolongation of absolute latencies I, V and III, followed by shortening of interpeak latency I-V. In addition, abnormalities (either shortening or prolongation) of absolute latencies I and V, as well as interpeak latency I-V, were significantly more common among patients. Taken together, BAEPs in 23% of patients were indicative of a clinically abnormal response in 32% of patients. As can be easily concluded, BAEPs abnormalities characterize only a subset of subjects with autism, who may be important to identify clinically. The latter individuals may benefit from targeted intervention to utilize brainstem plasticity.

Brainstem auditory evoked potentials in traffic policemen occupationally exposed to vehicular emission

Background and Aim: It is a well-known fact that traffic policemen in Delhi are exposed to immense vehicular pollution particularly at crowded intersections. These pollutants affect various systems of the body including nervous system in due course of time. Realizing these facts, we recorded absolute and inter peak latencies (IPLs) of brainstem auditory evoked potentials (BAEPs) in traffic policemen exposed to enormous vehicular emission and compared with the normal controls living in the residential areas in Delhi. Methods: Totally, 60 subjects all males and nonsmokers between 30 and 50 years of age were studied, 30 belonged to exposed group comprised of traffic policemen and 30 nonexposed controls. Their BAEPs were recorded using MEB 5200 Neuropack II plus evoked potential recorder (Nihon Kohden, Japan) and evaluation of anthropometric and neuro-psychiatric parameters was done. To compare BAEP results, Student's t -test was used. Results: Significantly prolonged absolute peak latencies I, II, III, IV, V and IPL I-III in exposed group were observed as compared to controls. Conclusion: Findings suggest prolongation of peripheral and central auditory conduction time in exposed subjects. The prolonged latencies in exposed group may be attributed to occupational exposure to vehicular emission.

Brainstem Auditory Evoked Potential Changes in Iron Deficient Anaemic Children

Iron deficiency anaemia adversely affects different aspects of the nervous system such as myelinogenesis, neurotransmitters synthesis, brain myelin composition, and brain fatty acid and eicosanoid metabolism. This study was carried out to see the effect of Iron deficiency anaemia on brainstem auditory evoked potentials in children of age group 5–14 yrs because anaemia is a common problem in this age group too. Children were taken from Pediatrics OPD of Pt. B.D. Sharma PGIMS, Rohtak. They were divided into two groups first, controls (n=30) and anaemics (n=50). Anaemics were further divided in mild, moderate and severe anaemics. Only proven cases of anaemia were taken having Hb<12gm/dl. BAEP was recorded by using RMS EMG EPMK2 machine. Results showed that there was a statistically significant increase in absolute peak latencies of different waves but the Interpeak latencies and amplitudes were not significantly different between the two groups. To conclude we can say that, there should be an increased awareness in the medical fraternity and the population in general, of deleterious effects of iron deficiency, some of which are subtle and subclinical and will likely to have a long term effect.

Brainstem evoked auditory response in preterm and full-term infants

Background: The survival of preterm infants has increased substantially over last few decades because of improvements in obstetric and neonatal care. However, the newborn experience many perinatal complications including peripheral or central hearing loss. The prevalence of hearing loss is reported to be 1.5–6 per 1000 newborn in the well-baby nursery population. Brainstem evoked response audiometry (BERA) is a simple, noninvasive way of evaluating the hearing function and has been widely used for early detection of hypoacusis and neural conduction irregularities in the auditory pathway. Several risk factors associated with hearing loss during early infancy, such as hereditary cause, in utero infection, prematurity, asphyxia, hyperbilirubinemia, and ototoxic medications, have been described by the Joint Committee on Infant Hearing. Aims & Objective: To analyze and compare BERA responses in preterm and term infants. Materials and Methods: The infants (30 preterm and 30 term) attending Pediatric OPD of Bapuji Hospital and Chigateri General Hospital satisfying the inclusion criteria were subjected to BERA. Parameters such as absolute latencies of waves I, III, and V, and interpeak latencies (IPLs) I–III, I–V, and III–V were assessed and analyzed by using unpaired t-test. Results: Preterm babies had highly significant increased wave V threshold than controls. Waves III and V were delayed in preterm babies, IPLs of wave III–V were increased in the preterm group, and statistically significant increase was observed in IPL of wave I–V. Conclusion: This study indicates that preterm infants have prolonged latency of wave V, which reflects immaturity of the auditory system. Therefore, it is essential to screen all preterm infants at the earliest to prevent adverse effect on the developing auditory pathway.