摘要:

AbstractThe subject of this case report is an 18 year-old woman with grossly abnormal auditory brain stem response (ABR), normal peripheral hearing, and specific behavioral auditory processing deficits. Auditory middle latency responses (MLRs) and cortical potentials NI, P2, and P300 were intact. The mismatch negativity (MMN) was normal in response to certain synthesized speech stimuli and impaired to others—consistent with her behavioral discrimination of these stimuli. Behavioral tests of auditory processing were consistent with auditory brain stem dysfunction. A neuropsychological evaluation revealed normal intellectual and academic performance. The subject was in her first year of college at the time of the evaluation. This case study is important because: (1) Although there have been saveral reports of absentdabnormal ABR with preserved peripheral hearing and deficits in auditory processing, little is known about the specific nature of the auditory deficits experienced by these individuals. Such information may be valuable to the clinical management of patients with this constellation of findings. (2) Of interest is the information that the mismatch negativity (MMN) cortical eventirelated potential can bring to the evaluation of patients with auditory processing deficits. The MMN reflects central auditory processing of small acoustic differences and may provide an objective measure of auditory discrimination. (3) From a theoretical standpoint, a patient with neural deficits affecting specific components of the auditory pathway provides insight into the relationship between evoked potentials and physiological mechanisms of auditory processing. How do various components of the auditory pathway contribute to speech discrimination? How might evoked potentials reflect the processes underlying the neural coding of specific features of speech stimuli such as timing and spectral cues?

ISSN:0196-0202    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

AbstractAuditory brain stem response (ABR) and middle latency response (MLR] were recorded in 49 epileptic patients. Responses were evoked and recorded at 90 dB nHL down to threshold. A statistically significant number of epileptic patients showed elevated ABR (30.1%] and MLR (40.7%) thresholds, even though their puretone audiograms showed normal hearing sensitivity. Threshold elevation was more frequent in subjects with grand mal epilepsy compared to subjects with temporal lobe epilepsy reflecting poorer response in the former subgroup. Furthermore, chronicity of illness was significantly related to the elevated ABR and MLR thresholds in grand ma1 patients in contrast to patients with temporal lobe epilepsy. On the other hand, the effect of antiepileptic drugs did not seem to be significantly related to the elevated thresholds in both subgroups. Threshold elevation was attributed to a disturbance in the neurotransmitters of the brain stem as well as other subcortical structures. The inhibitory effect of the efferent auditory pathway on the incoming neural signals was also suggested to explain such elevated thresholds.

ISSN:0196-0202    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

AbstractObscure Auditory Dysfunction (OAD) is explained by a combination of hearing-related deficits and personality factors Saunders 6 Haggard (1992). In this study, we determine which factors are associated specifically with OAD and which are associated with the seeking of medical attention in general. We achieved this by obtaining a second patient group with a parallel syndrome to OAD, called “chronic pelvic pain without obvious organic pathology” (CPPWOOP). CPPWOOP patients complain of lower abdominal pain that is not explainable by conventional medical tests. Fifteen CPPWOOPs underwent the OAD test battery. For the analyses they were retrospectively matched to 15 of the original OADs and their matched controls. The three groups were compared by analysis of variance and Kruskal Wallis analyses. The CPPWOOPs and controls performed significantly better than OADs on hearing-related variables, but did not differ from each other, whereas the OADs and CPPWOOPs were significantly more anxious than the controls, but did not differ from each other. We conclude that anxiety-related traits are associated with the seeking of medical attention in general, whereas the hearing-related deficits we measured are associated specifically with OAD. Anxiety-related traits should, therefore, be considered when dealing with marginal pathologies, but in depth investigation may also reveal an organic basis; therefore, patients should not be dismissed as simply neurotic.

ISSN:0196-0202    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

AbstractYoung adult hamsters were evaluated for normal variations in the auditory brain stem response (ABR) and for the effects of hearing loss. Normal variations in the ABR's latencies and amplitudes were defined for both click and tone burst stimuli over a broad range of intensities. As stimulus intensity decreased from 100 to 15 dB pe SPL, the ABR latencies were prolonged, the P441 interpeak latencies varied in a complex manner, and amplitudes decreased. As tone burst frequency decreased from 8000 to 4000 and then to 2000 Hz, ABR latencies were prolonged, amplitudes decreased, and thresholds increased. The P4P1 interpeak latencies were also influenced by tone burst frequency, with the longest interpeak latencies occurring in response to the 2000 Hz tone bursts. Data from two hamsters with hearing LOSE were compared to the normal data to illustrate haw the ABR can be used to describe experimentally induced hearing impairment. Hearing impairment was induced by rearing animals in ambient noise. These animals showed elevated ABR thresholds at all three frequencies and upward displacements in the ABR's latencyintensity profiles.

ISSN:0196-0202    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

AbstractFull-term and preterm infants were evaluated with click-evoked and distortion product otoacoustic emissions [CEOEs and DPOEs]. The CEOEs and DWEs recorded from each individual ear were analyzed by calculating the root-mean-square levels within half-active bands. The fail criterion of the OE tests was that the half-active RMS DPOE or CEOE levels of an ear under test were below the 10th percentile of full-term newborns in two or more bands. The DPOE data were collected from 118 ears of 61 premature babies; 80 (68%] ears passed the DPOE test, 30 [25%] ears without middle ear effusions failed the test, and 8 (7%] ears with effusions also failed. The CEOE data were collected from 128 ears of 65 premature babies; 102 (80%) ears passed the CEOE test, 18 (14%) ears without middle ear effusions failed the test, and 8 (6%] ears with effusions also failed. In 23 of 80 ears (29%) that passed the DWE test and in 23 of 102 ears (23%] that passed the CEOE test, RMS OE levels of preterm infants were above the 90th percentile of full-term newborns. The analyses of the combined DPOE and CEOE data obtained from a group of 25 ears of full-term newborns and from a group of 72 ears of preterm babies showed statistically significant correlations between the DPOE and CEOE root mean-square levels in each of the half-octave bands in the 1.4 to 4 kHz region. For 42 preterm infants tested with auditory brain stem response [ABR), specificity was 86% for CEOE and 74% for DPOE. All infants who failed the ABR also failed OE tests. To the best of our knowledge, this study is the first using combined DWEs, CEOEs, and ABRs for preterm babies. It showed the feasibility of DWEs and CEOEs for this population.

ISSN:0196-0202    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

AbstractHearing aid benefit, defined in terms of improved speech intelligibility, was measured for 16 elderly hearing impaired subjects. Twelve conditions were tested, simulating a range of daily situations from typical home environments to moderete-sized social gatherings, and assuming a small talker listener distance [thus maintaining essentially nonreverberant listening conditions]. Each subject was fitted with the same type of programmable hearing aid. The goals were to develop a model for the prediction of benefit based on hearing loss, listening environment, and amplification variables, and to assess the potential accuracy of the model. Two models were developed using multiple linear regression analyses. The prefitting model used data that would be available before a hearing aid fining, that is, audiogram and listening environment data. This model, although potentially useful as a counseling tool, was relatively inaccurate. Six of the 16 subjects yielded benefit data that were consistently different from the model's predictions. The postfitting model used information that could be obtained during a hearing aid fitting about audibility changes resulting from amplification. This model produced more accurate, but still imperfect predictions of benefit. Benefit obtained by three subjects deviated substantially from the predictions of the postfitting model. It was concluded that a model producing fairly accurate benefit predictions must encompass additional variables beyond those considered here. Nevertheless, these models may be useful for prediction of typical benefit for potential hearing aid wearers.

ISSN:0196-0202    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

AbstractSelf-report hearing handicap scales are gaining widespread acceptance among clinicians as a technique for quantifying hearing aid benefit. Both auditory and nonauditory [e.g., personality, health, motivation) factors contribute to an individual's response to hearing loss and ultimately to perceived hearing aid benefit. Among the recognized extra-audiological variables, financial concerns may influence a hearing aid user's expectations regarding hearing aid benefit. The present study compared self-perceived benefit in 26 insured and 26 uninsured new hearing aid wearers using the Hearing Handicap Inventory for the Elderly [HHIE). HHIE scores at 3 weeks and 6 mo postfitting were equivalent between groups. The findings suggest that the HHIE may be used as an index of hearing aid benefit without concern that the source of funds required to purchase amplification may act as an uncontrolled variable.

ISSN:0196-0202    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

AbstractEstimates of loudness balance were obtained for acoustically and electrically presented 250 Hz sine signals from a patient who uses the Ineraid multichannel cochlear implant. Acoustic and electric loudness matching was possible because the patient evidenced a 25 dB HL threshold at 250 Hz in his nonimplanted ear. The level of the electrical stimulus in microamperes required for a balance of loudness grew linearly with equal increments in decibels for the acoustic stimulus. These data, in concert with the very limited data from previous studies, provide a rationale for using a logarithmic transformation of acoustic to electric intensity in signal processors for cochlear implants.

ISSN:0196-0202    

出版商:OVID    

年代:1993

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1993

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1993

数据来源: OVID