Auditory Brainstem Response Wave Latencies Research Articles

Evaluation of cochlear and auditory brainstem functions in COVID-19 patients; a case control study

BackgroundMany viral infections can cause hearing loss due to affection of cochlear hair cells or neurogenic pathway. Although, the damage secondary to viral infections is mainly cochlear affection; auditory brainstem can be affected as well. It was predicted that SARS-COV-2 infection can similarly affect the auditory system. This study aimed to detect affection in auditory system and if present investigate the possible site of lesion (up to the level of the brain stem) in relation to COVID-19 infection.MethodsThis is a case control study, where the study group constituted of thirty adults, diagnosed with COVID-19 at least 2 weeks prior to testing and up to 6 months, without previous auditory complaints pre-COVID-19 or other risk factors that could affect the auditory pathway. Fifteen adult participants that were age and gender matched to the study group with no previous history of covid-19 infection constituted the control group. Audiological evaluations done to all participants were pure-tone and speech audiometry, tympanometry, transient-evoked otoacoustic emission with and without contralateral suppression and auditory brainstem response measurements.ResultsThe study group showed significantly worse pure tone thresholds at high frequencies 4 and 8 kHz (p < 0.01), significantly worse transient-evoked otoacoustic emission signal to noise ratio at 2800 Hz and 4000 Hz (p < 0.05) and significantly lower total suppression index (p<0.05). On the other hand, there was no significant difference between both groups in auditory brainstem response wave latencies (p > 0.05).ConclusionCOVID-19 had subtle effect on cochlear basal turn, and it is shown that the auditory efferent system may also be affected, while the auditory nerve and afferent brainstem pathways seems to be spared. Moreover, the absence of the symptoms of auditory dysfunction postcovid-19 does not guarantee normal auditory functions.

Investigating the optimal stimulus to evoke the binaural interaction component of the auditory brainstem response

Objective assessment of spatial and binaural hearing deficits remains a major clinical challenge. The binaural interaction component (BIC) of the auditory brainstem response (ABR) holds promise as a non-invasive biomarker for diagnosing such deficits. However, while comparative studies have reported robust BIC in animal models, BIC in humans can sometimes be unreliably evoked even in subjects with normal hearing. Here we explore the hypothesis that the standard methodology for collecting monaural ABRs may not be ideal for electrophysiological assessment of binaural hearing. This study aims to improve ABR BIC measurements by determining more optimal stimuli to evoke it. Building on previous methodology demonstrated to enhance peak amplitude of monaural ABRs, we constructed a series of level-dependent chirp stimuli based on empirically derived latencies of monaural-evoked ABR waves I, IV and the binaural-evoked BIC DN1, the most prominent BIC peak, in a cohort of ten chinchillas. We hypothesized that chirps designed based on BIC DN1 latency would specifically enhance across-frequency temporal synchrony in the afferent inputs leading to the binaural circuits that produce the BIC and would thus produce a larger DN1 than either traditional clicks or chirps designed to optimize monaural ABRs. Compared to clicks, we found that level-specific chirp stimuli evoked significantly greater BIC DN1 amplitudes, and that this effect persisted across all stimulation levels tested. However, we found no significant differences between BICs resulting from chirps created using binaural-evoked BIC DN1 latencies and those using monaural-evoked ABR waves I or IV. These data indicate that existing level-specific, monaural-based chirp stimuli may improve BIC detectability and reduce variability in human BIC measurements.

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.

Comparison of click and chirp stimuli in evoking the binaural interaction component of the auditory brainstem response

Chirp stimuli enhance synchrony in the auditory nerve by compensating for frequency- and level-dependent delays accrued by the traveling wave in the cochlea. Chirps produce larger amplitudes in specific waves of the monaural auditory brainstem response (ABR). We test whether chirps increase the amplitude of the binaural interaction component (BIC) of the ABR, a potential biomarker for binaural hearing. ABR latencies were measured across multiple stimulus frequencies and intensities in chinchillas. Tone bursts (1–16 kHz) were presented ∼10 dB below to 50 dB above threshold. Latencies of ABR waves I-IV and BIC were plotted against frequency and fit to a power function: Tau = k*f(-d), where tau is latency, f is frequency, and k and d are constants. The values of k and d were used to construct chirps for three intensity-levels based on monaural ABR waves I and IV, and BIC. Monaural ABR latencies decreased with increasing frequency as expected from cochlear delay. Monaural ABR amplitudes were enhanced by chirps relative to clicks. Surprisingly, BIC DN1 latencies did not show a similar shift but rather appeared constant across frequency. Traditional chirp stimuli appear ill-suited for eliciting optimal BIC amplitudes. Traditional broadband clicks or non-traditional chirps may be preferable for evoking the BIC.

Delayed Auditory Brainstem Responses (ABR) in children after sight-recovery

Studies in non-human animal models have revealed that in early development, the onset of visual input gates the critical period closure of some auditory functions. The study of rare individuals whose sight was restored after a period of congenital blindness offers the rare opportunity to assess whether early visual input is a prerequisite for the full development of auditory functions in humans as well. Here, we investigated whether a few months of delayed visual onset would affect the development of Auditory Brainstem Responses (ABRs). ABRs are widely used in the clinical practice to assess both functionality and development of the subcortical auditory pathway and, provide reliable data at the individual level. We collected Auditory Brainstem Responses from two case studies, young children (both having less than 5 years of age) who experienced a transient visual deprivation since birth due to congenital bilateral dense cataracts (BC), and who acquired sight at about two months of age. As controls, we tested 41 children (sighted controls, SC) with typical development, as well as two children who were treated (at about two months of age) for congenital monocular cataracts (MC). The SC group data served to predict, at the individual level, wave latencies of each BC and MC participant. Statistics were performed both at the single subject as well as at the group levels on latencies of main ABR waves (I, III, V and SN10). Results revealed delayed response latencies for both BC children compared with the SC group starting from the wave III. Conversely, no difference emerged between MC children and the SC group. These findings suggest that in case the onset of patterned visual input is delayed, the functional development of the subcortical auditory pathway lags behind typical developmental trajectories. Ultimately results are in favor of the presence of a crossmodal sensitive period in the human subcortical auditory system.

Electrocochleography and Auditory Brainstem Responses in Persons with Non-Optimal Blood Pressure.

Numerous cardiometabolic factors may underlie risk of hearing loss. Modifiable risk factors such as non-optimal blood pressure (BP) are of interest. To investigate early auditory evoked potentials (AEPs) in persons with nonoptimal BP. A cross-sectional nonexperimental study was performed. Fifty-two adults (18-55 years) served as subjects. Individuals were classified as having optimal (systolic [S] BP < 120 and diastolic [D] BP < 80 mm Hg, n = 25) or non-optimal BP (SBP ≥=120 or DBP ≥=80 mm Hg or antihypertensive use, n = 27). Thirteen subjects had hypertension (HTN) (SBP ≥130 or DBP ≥80 mm Hg or use of antihypertensives). Behavioral thresholds from 0.25 to 16 kHz were collected. Threshold auditory brain stem responses (ABRs) were recorded using rarefaction clicks (17.7/second) from 80 dB nHL to wave V threshold. Electrocochleograms were obtained with 90 dB nHL 7.1/second alternating clicks and assessed for summating and compound action potentials (APs). Outcomes were compared via independent samples t tests. Linear mixed effects models for behavioral thresholds and ABR wave latencies were constructed to account for potential confounders. Wave I and III latencies were comparable between optimal and non-optimal BP groups. Wave I was prolonged in hypertensive versus optimal BP subjects at stimulus level 70 dB nHL (p = 0.016). ABR wave V latencies were prolonged in non-optimal BP at stimulus level 80 dB nHL (p = 0.048) and in HTN at levels of 80, 50, and 30 dB nHL (all p < 0.050). DBP was significantly correlated with wave V latency (r = 0.295; p = 0.039). No differences in ABR amplitudes were observed between optimal and non-optimal BP subjects. Electrocochleographic study showed statistically comparable action and summating potential amplitudes between optimal and non-optimal BP subjects. AP latencies were also similar between the groups. Analysis using a set baseline amplitude of 0 μV showed that hypertensive subjects had higher summating (p = 0.038) and AP (p = 0.047) amplitudes versus optimal BP subjects; AP latencies were comparable. Elevated BP and more specifically, HTN was associated with subtle AEP abnormalities. This study provides preliminary evidence that nonoptimal BP, and more specifically HTN, may be related to auditory neural dysfunction; larger confirmatory studies are warranted.

Limitation of Conventional Audiometry in Identifying Hidden Hearing Loss in Acute Noise Exposure.

PurposeThe concept of hidden hearing loss can explain the discrepancy between a listener's perception of hearing ability and hearing evaluation using pure tone audiograms. This study investigated the utility of the suprathreshold auditory brainstem response (ABR) for the evaluation of hidden hearing loss in noise-exposed ear with normal audiograms.Materials and MethodsA total of 15 patients (24 ears) with normal auditory thresholds and normal distortion product otoacoustic emissions were included in a retrospective analysis of medical records of 80 patients presenting with histories of acute noise exposure. The control group included 12 subjects (24 ears) with normal audiograms and no history of noise exposure. Pure tone audiometry and suprathreshold ABR testing at 90 dB peSPL were performed. The amplitudes and latencies of ABR waves I and V were compared between the noise-exposed and control groups.ResultsWe found no significant difference in the wave I or V amplitude, or the wave I/V ratio, between the two groups. The latencies of ABR wave I, V, and I-V interpeak interval were compared, and no significant intergroup difference was observed.ConclusionThe results suggest that either hidden hearing loss may not be significant in this cohort of patients with acute noise exposure history, or the possible damage by noise exposure is not reflected in the ABRs. Further studies are needed to inquire about the role of ABR in identification of hidden hearing loss.

Automated extraction of auditory brainstem response latencies and amplitudes by means of non-linear curve registration

Background and objectivesAnimal results have suggested that auditory brainstem responses (ABRs) to transient sounds presented at supra-threshold levels may be useful for measuring hearing damage that is hidden to current audiometric tests. Evaluating such ABRs requires extracting the latencies and amplitudes of relevant deflections, or “waves”. Currently, this is mostly done by human observers manually picking the waves’ peaks and troughs in each individual response – a process that is both time-consuming and requiring of expert experience. Here, we propose a highly automated procedure for extracting individual ABR wave latencies and amplitudes based on the well-established methodology of non-linear curve registration. MethodsFirst, the to-be-analysed individual ABRs are temporally aligned – either with one another or, if available, with a pre-existing template – by locally compressing or stretching their time axes with smooth and invertible time warping functions. Then, the individual latencies and amplitudes of relevant ABR waves are obtained by picking the latencies of the waves’ peaks and troughs on the common (aligned) time axis and combining these with the individual aligned responses and inverse time warping functions. ResultsUsing an example ABR data set with a wide range of response latencies and signal-to-noise ratios (SNRs), we test different choices for fitting the time warping functions. We cross-validate the warping results using independent response replicates and compare automatically and manually extracted latencies and amplitudes for ABR waves I and V. Using a Bayesian approach, we show that, for the best registration condition, automatic and manual data were statistically similar. ConclusionsNon-linear curve registration can be used to temporally align individual ABRs and extract their wave latencies and amplitudes in a way that closely matches results from manual picking.

Alterations in brainstem auditory processing, the acoustic startle response and sensorimotor gating of startle in Wistar audiogenic rats (WAR), an animal model of reflex epilepsies

While acute audiogenic seizures in response to acoustic stimulus appear as an alteration in sensory-motor processing in the brainstem, the repetition of the stimulus leads to the spread of epileptic activity to limbic structures. Here, we investigated whether animals of the Wistar Audiogenic Rat (WAR) strain, genetically selected by inbreeding for seizure susceptibility, would have alterations in their auditory response, assessed by the auditory brainstem responses (ABR) and sensory-motor gating, measured as pre-pulse inhibition (PPI), which could be related to their audiogenic seizures susceptibility or severity. We did not find differences between the amplitudes and latencies of ABR waves in response to clicks for WARs when compared to Wistars. Auditory gain and symmetry between ears were also similar. However, hearing thresholds in response to some tones were lower and amplitudes of wave II were larger in WARs. WARs had smaller acoustic startle reflex amplitudes and the percentages of startle inhibited by an acoustic prepulse were higher for WARs than for Wistars. However, no correlation was found between these alterations and brainstem-dependent seizure severity or limbic seizure frequency during audiogenic kindling. Our data show that while WARs present moderate alterations in primary auditory processing, the sensory motor gating measured in startle/PPI tests appears to be more drastically altered. The observed changes might be correlated with audiogenic seizure susceptibility but not seizures severity.

Hearing impairment and associated morphological changes in pituitary adenylate cyclase activating polypeptide (PACAP)-deficient mice

Pituitary adenylate cyclase activating polypeptide (PACAP) is a regulatory and cytoprotective neuropeptide, its deficiency implies accelerated aging in mice. It is present in the auditory system having antiapoptotic effects. Expression of Ca2+-binding proteins and its PAC1 receptor differs in the inner ear of PACAP-deficient (KO) and wild-type (WT) mice. Our aim was to elucidate the functional role of PACAP in the auditory system. Auditory brainstem response (ABR) tests found higher hearing thresholds in KO mice at click and low frequency burst stimuli. Hearing impairment at higher frequencies showed as reduced ABR wave amplitudes and latencies in KO animals. Increase in neuronal activity, demonstrated by c-Fos immunolabeling, was lower in KO mice after noise exposure in the ventral and dorsal cochlear nuclei. Noise induced neuronal activation was similar in further relay nuclei of the auditory pathway of WT and KO mice. Based on the similar inflammatory and angiogenic protein profile data from cochlear duct lysates, neither inflammation nor disturbed angiogenesis, as potential pathological components in sensorineural hearing losses, seem to be involved in the pathomechanism of the presented functional and morphological changes in PACAP KO mice. The hearing impairment is probably concomitant with the markedly accelerated aging processes in these animals.

Chapter 30 - Auditory brainstem response

The auditory brainstem response (ABR), consisting of five to six vertex-positive peaks with separation of about 0.8ms, is very sensitive to factors that affect conduction velocity and hence ABR wave latencies in the brainstem auditory pathways. In addition, disorders causing dissynchronization of neural activity result in an amplitude decrease or disappearance of ABR peaks. The opposite effects occur in the maturation process, which takes about 2 years postterm; here conduction velocity increases quickly to its adult value, but synaptic delays being sensitive to synchronous release of transmitter substance take considerably longer. In neurological disorders, those that cause dissynchrony, such as auditory neuropathy and vestibular schwannoma, Gaucher disease, and Krabbe disease, the (longer latency) ABR peaks are reduced or absent. Effects on neural conduction, resulting in increased ABR interwave latencies, are found in vestibular schwannomas, Bell's palsy, Duane retraction syndrome, Marcus Gunn ptosis, and various encephalomyopathies. These measures allow an assessment of the parts of the brainstem that are involved.

Is COPD associated with alterations in hearing? A systematic review and meta-analysis.

Background and aimsCOPD is an irreversible or persistent airflow obstruction, which affects up to 600 million people globally. The primary purpose of this systematic review was to explore the COPD-based alteration in the auditory system function by conducting a quantitative analysis of presently published data.Materials and methodsWe systematically searched seven diverse electronic databases and manual searching of references to identify relevant studies. Data from the selected studies were rated by two investigators independently in a blinded fashion. Meta-analysis was done on pooled data using Cochrane’s Review Manager 5.3.ResultsSixteen articles received suitable scores and were thus included for further processes. Hearing loss (HL) was defined as a change in pure tone audiometry (PTA) thresholds, auditory brainstem response (ABR), and auditory P300 parameters. ABR wave was significantly elongated in patients with COPD than in controls (standardized mean difference [SMD]=0.27, 95% CI: 0.05–0.48, P=0.02). PTA was significantly higher in patients with COPD when compared with controls (SMD=1.76, 95% CI: 0.43–3.08, P=0.0004). We found that patients with COPD had a significantly higher latency than controls (SMD=1.30, 95% CI: 0.79–1.80, P=0.0001).ConclusionCOPD patients had considerably greater incidence of HL when compared with controls. Interestingly, although the mean PTA thresholds at every frequency for COPD patients were higher than those for controls, these values were still in the slight to mild HL ranges. Prolonged ABR wave latencies in the COPD patients suggest retro-cochlear involvement. Thus, COPD most frequently clusters with HL, but it is worth noting that alteration in hearing is not always recognized by medical experts as a frequent comorbidity associated with COPD.

Is Chronic Obstructive Pulmonary Disease Associated with Alterations in Hearing? A Systematic Review and Meta-Analysis

Background and Aims: Chronic obstructive pulmonary disease (COPD) affects up to 600 million people worldwide and it is currently one of the leading causes of morbidity and mortality in patients suffering from chronic diseases. The primary purpose of this study was to conduct a systematic review in order to explore the effects of COPD on the auditory system function by performing a quantitative analysis of currently available published data on this subject. Methods: We systematically searched seven diverse electronic databases and manual searching of references to identify relevant studies. Data from the selected studies were rated by two investigators independently in a blinded fashion. Meta-analysis was done on pooled data using Cochrane's Review Manager 5. Results: Sixteen articles received suitable scores and were thus included for further processes. Hearing loss (HL) was defined by all studies as change in pure tone audiometry (PTA) thresholds, auditory brainstem response (ABR) and auditory P300 parameters. ABR waves was significantly elongated in patients with COPD than in controls (SMD = 0.27; 95%CI: 0.05-0.48; P = 0.02). PTA was significantly higher in patients with COPD when compared with control cases (SMD = 1.76; 95%CI: 0.43-3.08; P=0.0004). We found that patients with COPD had a significantly higher latency than controls (SMD = 1.30; 95%CI: 0.79-1.80; P=0<0001). Conclusions: COPD patients had considerably greater incidence for HL when compared with controls. Interesting, although the mean PTA thresholds at every frequency for COPD patients was higher than those for controls, these values were still in the slight to mild hearing loss ranges. Prolonged ABR wave latencies in the COPD patients suggest retro-cochlear involvement. Thus COPD most frequently clusters with HL, which is worth noting that alteration in hearing is not always recognized by medical experts as frequent comorbidity associated with COPD. Funding: None Conflict of interest: None

Is there a relationship between perceptual difficulties and auditory functioning at the periphery and the brainstem in children suspected with auditory processing disorder?

The test battery typically used for the diagnosis of auditory processing disorder (APD) is highly heterogeneous, with an emphasis on the central auditory nervous system. As such, the peripheral auditory system is typically only screened for the presence of an overt hearing loss. Our previous work suggested that children suspected of APD (sAPD) have atypically sharp cochlear tuning when measured using stimulus frequency otoacoustic emission (SFOAE) group delay. In the present work, we extend our previous findings and test the hypothesis that cochlear tuning influences auditory brainstem response (ABR) latencies. Our hypothesis is based on filter theory, which suggests that a sharper filter will take longer to build-up and ring longer. We predicted that sharper cochlear filters in sAPD should result in delayed ABR wave latencies and will be associated with poorer performance on speech perception tests. Preliminary data from 16 sAPD and 6 typically developing children show a positive correlation between cochlear tuning and ABR peak I latency. Cochlear tuning explains a significant proportion of the variance in ABR peak I latency (R2 = 0.25). Further behavioral results and implications for inclusion of auditory peripheral examination in APD tests will be discussed.

The relationship between presbycusis and vestibular activity

Introduction Presbycusis or age-related sensorineural hearing loss (SNHL) is a complex disorder that results in a slow deterioration in auditory function. A considerably high number of these patients with presbycusis or age-related SNHL also experience dizziness and related vestibular symptoms. Although auditory and vestibular systems are distinct, they work just alike. So, there is a great relation among their functions. Once one is stimulated, the other experiences changes as well. Participants and methods This study comprised 40 adult patients (50–75 years) without any vestibular symptoms or diagnosed vestibular diseases. Audiological status was measured with auditory brainstem response (ABR). The vestibular system was assessed using videonystagmography test battery, sensory organization test, and vestibular evoked myogenic potential (VEMP). ‘Get up and go’ test was used as a quick screening tool for detecting balance problems. Patients were divided into two groups: a study group (patients with SNHL) and a control group (patients without SNHL). ABR and VEMP results of the groups were calculated and compared. Results Absolute peak latencies of ABR waves I, III, and V were prolonged in the study group than the control group (P Conclusion Thorough full examination of the vestibular system, in conjunction with auditory functions in elderly persons, is recommended. This may help to discover their subclinical vestibular problem and guide physicians to design a suitable treatment plan that helps in decreasing risk of falls for aged persons.

Improving the efficiency of Auditory Brainstem Responses in newborns, using a 60 clicks/s stimulation rate

Recent evidence suggests that Auditory Brainstem Responses (ABR), in neonates with risk factors for neurological damage, may show auditory brainstem abnormalities, even in patients with normal hearing. To compare the recording and diagnostic accuracy of neonatal Auditory Brainstem Responses (ABR), using 10 and 60clicks/s stimulation rates, two groups of neonates were prospectively studied: 30 healthy full-term neonates, with no peri- or postnatal complications; and 30 high-risk newborns with two or more of the following conditions: hyperbilirubinemia, use of ototoxic drugs, birth weight inferior to 1500g, perinatal sepsis, intraventricular hemorrhage, and/or mechanical ventilation. Correlation between ABR trials, recording duration, and the absolute and interpeak latencies of ABR waves I, III and V, were measured. ROC-curve analysis assessed the diagnostic accuracy of both stimulation rates. The correlations between ABRs trials were significantly higher at 60clicks/s than at 10clicks/s (F(1,116)=14.5, p<0.0002). Recording duration at 60clicks/s was significantly lower (t=20.9, p<0.0001). ROC-curve comparisons showed increased diagnostic accuracy at the stimulation rate of 60clicks/s, for waves I (D=2.04, p=0.04), V (D=2.02, p=0.04), interpeak latencies III-V (D=2.2, p=0.02), and I-V (D=2.86, p=0.004). In neonates, the use of 60clicks/s stimulation rate permits a substantial shortening of the ABR recording, with greater diagnostic accuracy and replicability.

AMPLITUDE AND LATENCY OF AUDITORY BRAINSTEM RESPONSES CORRELATE WITH IMPAIRMENT IN ACTIVITIES OF DAILY LIVING IN HEALTHY ELDERS

There is increasing epidemiological evidence showing an association between presbycusis or age-related hearing loss and cognitive decline in elderly people. The Health ABC Study has shown that presbycusis subjects with audiometric hearing thresholds (PTA) worse than 40 dB are more likely to develop cognitive decline. Before the development of audiometric hearing loss, aged subjects could have communication problems, a clinical entity known as hidden hearing loss (HHL). The amplitudes and latencies of auditory brainstem responses (ABR) at supra-thresholds levels have been used as objective measures to detect HHL. Objective: To study whether supra-thresholds ABR responses are associated with impairment in activities of daily living (ADL) in healthy elders. 52 Persons from the ANDES study ≥65 years without dementia (MMSE>24) with normal hearing thresholds (PTA<20dB, n=13), with mild (PTA 20–39dB, n=29) or moderate presbycusis (PTA≥40dB, n=10), were evaluated with a comprehensive neuropsychological assessment, questionnaires of ADL and with auditory measurements including: PTA, and amplitudes and latencies of ABR waves I and V obtained at supra-thresholds levels. Neuropsychological and ADL data were compared between groups of hearing impairment, and lineal regressions between these data and different auditory assessment were performed. Those with moderate presbycusis (n=10) had more perseverative errors in the Wisconsin card sorting task (ANOVA, F(2)=3.4, p=0.04) than the other groups, without any other differences in the neuropsychological or ADL assessment (Table 1). Instrumental ADL impairments were correlated with latencies of bilateral ABR waves V: shopping (right: r=0.44, p=0.001; left: r=0.63, p<0.001), work (right: r=0.33, p=0.02; left: r=0.3, p<0.03) and house hold (right: r=0.29, p=0.04; left: r=0.39, p<0.006). Once excluding those with moderate presbycusis, we found significant correlations in the latencies of left wave V for house hold (r=0.38, p=0.013) and for communication (r=0.36, p=0.019). In addition, the amplitudes of wave I from the left ear were correlated with impairment in traveling (r=-0.40, p=0.013) and technology (r=-0.45, p=0.005). Supra-thresholds ABRs are good predictors of ADL impairments in elderlies without evident cognitive or hearing impairment. These results reinforce the study of other risk factors for cognitive decline in the elderly. Funded by Anillo ACT1403, Fondecyt 1140423, Fondecyt 1161155.

HIDDEN HEARING LOSS AND COGNITIVE MEASURES IN HEALTHY ELDERS

Epidemiological evidence shows an association between presbycusis or age-related hearing loss and cognitive decline in elderly people. Presbycusis subjects with audiometric hearing thresholds (PTA) worse than 40 dB are more likely to develop cognitive decline. The mechanisms of this epidemiological association are unknown. Here we propose that hidden hearing loss (HHL), that is the loss of auditory-nerve neurons without alterations at the audiometric thresholds, is an important factor linking presbycusis and cognitive decline. HHL can be assessed using supra-thresholds auditory brainstem responses (ABR). Analyze supra-thresholds ABR responses and cognitive measures in healthy elders. 52 Persons from the ANDES study ≥65 years without dementia (MMSE>24) with normal hearing thresholds (PTA<20dB, n=13), with mild (PTA: 20–39dB, n=29) or moderate presbycusis (PTA≥40dB, n=10), were evaluated using a comprehensive neuropsychological assessment and with the self-reported questionnaire of hearing handicap inventory for the elderly (HHIE). Amplitudes and latencies of ABR waves I and V were obtained at supra-thresholds levels. The ratio between wave I/V was computed as a measure of HHL. These ABR variables were analyzed and correlated with cognitive tests. Those with moderate presbycusis had significant higher scores in the HHIE (F(2)=5.80, p=0.005). The MMSE score correlated with the amplitude (r=0.40, p=0.006) and latency (r=-0.38, p=0.009) of wave I, and the amplitude ratio (waves I/V) (r=0.38, p=0.009) of the right ear. The Boston test correlated with bilateral amplitude ratios (wave I/V) of wave I (right: r=0.34, p=0.023; left: r=0.37, p=0.013). The Wisconsin card sorting test correlated with the amplitude of right ABR waves I (r=0.30, p=0.03) and V (r=0.32, p=0.03). The Corsi test with (r=0.33, p=0.28) and without (r=0.33, P=0.03) noise correlated with the amplitude ratio of wave I/V in the left ear. Auditory nerve supra-thresholds responses correlate with several cognitive measures in healthy elderly subjects. These preliminary results should be confirmed with a larger sample of presbycusis patients. Funded by Proyecto Anillo ACT1403, Fondecyt 1140423, and Fondecyt 1161155.

Neurovegetative disorders of perimenopausal women treated with docosahexaenoic acid (DHA, 625 mg)

The study evaluated the effect of DHA 625 mg in women who experience menopausal symptoms, on sexuality and quality of life (QoL), and on the auditory brainstem response (ABR). Forty-two perimenopausal women were enrolled. The Kupperman Index (KI) was used to evaluate menopause symptoms. The Short Form-36 (SF-36), Female Sexual Function Index (FSFI), and the Female Sexual Distress Scale (FSDS) were used to assess QoL, sexual function, and sexual distress, respectively. Auditory evoked potentials to measure the ABR. The study had one follow-up at 6 months. The women reported an improvement in the KI total score (p < .001). Moreover, women reported QoL improvements in all the psychological categories (p < .001), but not in physical categories (p = NS). FSFI and FSDS total scores increased (p < .01) and the FSDS score decreased (p < .01), mainly due to arousal (p < .03) and lubrication (p < .05) sexual aspects. The ABR wave latencies were lower than the baseline values (p < .05). DHA could be effective in modulating some perimenopausal symptoms in women and, consequently could contribute to improve their QoL and sexual life. Finally, DHA seems to have a direct activity on the neuronal conduction time into the audiological system.

Auditory brain stem response and cortical evoked potentials in children with type 1 diabetes mellitus

Conclusions: Delay in ABR and CAEPs wave latencies in children with type 1DM indicates that there is abnormality in the neural conduction in DM patients. The duration of DM has greater effect on auditory function than the control of DM.Background: Diabetes mellitus (DM) is a common endocrine and metabolic disorder. Evoked potentials offer the possibility to perform a functional evaluation of neural pathways in the central nervous system.Objectives: To investigate the effect of type 1 diabetes mellitus (T1DM) on auditory brain stem response (ABR) and cortical evoked potentials (CAEPs).Method: This study included two groups: a control group (GI), which consisted of 20 healthy children with normal peripheral hearing, and a study group (GII), which consisted of 30 children with type I DM. Basic audiological evaluation, ABR, and CAEPs were done in both groups.Results: Delayed absolute latencies of ABR and CAEPs waves were found. Amplitudes showed no significant difference between both groups. Positive correlation was found between ABR wave latencies and duration of DM. No correlation was found between ABR, CAEPs, and glycated hemoglobin.