Biomedical subjects

Barbara Cone-Wesson

Publications and source records attributed to Barbara Cone-Wesson.

8 recordsLinked to original sources

PubMed2006

Lateral asymmetry in the ABR of neonates: evidence and mechanisms.

Lateralized processing of auditory stimuli occurs at the level of the auditory cortex but differences in function between the left and right sides are not clear at lower levels of the auditory system. The current study is designed to (1) investigate asymmetric auditory function at the ear and brainstem in human infants and (2) investigate possible mechanisms for asymmetry at these levels. Study 1 evaluated auditory brainstem responses (ABRs) in response to high and low-level clicks presented to the right and left ears of neonates. Wave V was significantly larger in amplitude and waves III and V were shorter in latency when the ABR was generated in the right ear. Study 2 investigated two possible mechanisms of such asymmetry by (a) using contralateral white noise masking to activate the medial olivocochlear system and (b) increasing stimulus rate to reveal neural conduction and synaptic mechanisms. ABR wave V, evoked by clicks to the left ear, showed a greater reduction in amplitude with contralateral noise than the response evoked from the right ear. No systematic asymmetries in ABR latencies or amplitudes were found with increased stimulus rate. We conclude that (1) the click-evoked ABR in neonates demonstrates asymmetric auditory function with a small but significant right ear advantage and (2) asymmetric activation of the medial olivocochlear system, specifically greater contralateral suppression of ABR produced by the left ear, is a possible mechanism for asymmetry.

Acoustic Stimulation↗

PubMed2006

Slight/mild sensorineural hearing loss in children.

OBJECTIVE: The goal was to determine the prevalence and effects of slight/mild bilateral sensorineural hearing loss among children in elementary school. METHODS: A cross-sectional, cluster-sample survey of 6581 children (response: 85%; grade 1: n = 3367; grade 5: n = 3214) in 89 schools in Melbourne, Australia, was performed. Slight/mild bilateral sensorineural hearing loss was defined as a low-frequency pure-tone average across 0.5, 1, and 2 kHz and/or a high-frequency pure-tone average across 3, 4, and 6 kHz of 16 to 40 dB hearing level in the better ear, with air/bone-conduction gaps of < 10 dB. Parents reported children's health-related quality of life and behavior. Each child with slight/mild bilateral sensorineural hearing loss, matched to 2 normally hearing children (low-frequency pure-tone average and high-frequency pure-tone average of < or = 15 dB hearing level in both ears), completed standardized assessments. Whole-sample comparisons were adjusted for type of school, grade level, and gender, and matched-sample comparisons were adjusted for nonverbal IQ scores. RESULTS: Fifty-five children (0.88%) had slight/mild bilateral sensorineural hearing loss. Children with and without sensorineural hearing loss scored similarly in language (mean: 97.2 vs 99.7), reading (101.1 vs 102.8), behavior (8.4 vs 7.0), and parent- and child-reported child health-related quality of life (77.6 vs 80.0 and 76.1 vs 77.0, respectively), but phonologic short-term memory was poorer (91.0 vs 102.8) in the sensorineural hearing loss group. CONCLUSIONS: The prevalence of slight/mild bilateral sensorineural hearing loss was lower than reported in previous studies. There was no strong evidence that slight/mild bilateral sensorineural hearing loss affects adversely language, reading, behavior, or health-related quality of life in children who are otherwise healthy and of normal intelligence.

Child↗

PubMed2005

Prenatal alcohol and cocaine exposure: influences on cognition, speech, language, and hearing.

UNLABELLED: This paper reviews research on the consequences of prenatal exposure to alcohol and cocaine on children's speech, language, hearing, and cognitive development. The review shows that cognitive impairment, learning disabilities, and behavioral disorders are the central nervous system manifestations of fetal alcohol syndrome (FAS), and cranio-facial abnormalities are also present. Delays in language acquisition, as well as receptive and expressive language deficits, are commonly reported. The cranio-facial abnormalities of FAS, which sometimes include cleft palate, make the child prone to otitis media with effusion and conductive hearing loss. The family environment in which one or both parents is a heavy alcohol user presents challenges to a child with normal intelligence, but may be especially deleterious to the child with mental retardation. Prenatal exposure to cocaine results in subtle cognitive disabilities when measured at 4 years of age. The cognitive effects may be ameliorated by a stimulating and sensitive care-giving environment. A small, deleterious "cocaine-effect" is also seen in speech and language development. The child with prenatal exposure to cocaine may be considered at increased risk for language delay or disorder. There is no evidence that prenatal cocaine exposure by itself is a risk factor for sensorineural hearing impairment, although auditory evoked potentials from the brainstem and cortex suggest some abnormalities in central auditory processing, at least during the newborn period. The strong effect of the home environment for ameliorating the effects of prenatal cocaine-exposure suggests that a family-focused approach for cognitive, language, and social-emotional habilitation would be beneficial to all. LEARNING OUTCOMES: The learner will be able to describe the major features of fetal alcohol syndrome and how they relate to speech, language, hearing, and cognitive disorders. The learner will review the literature and determine research needs with respect to language, speech, and hearing among infants and children with fetal alcohol syndrome. Similarly, the learner will distinguish the outcomes of prenatal alcohol-exposure from those of prenatal cocaine-exposure. The learner will summarize the controversy regarding the possible stigmatization of cocaine-exposed infants. The learner will summarize the speech, language, and hearing effects of prenatal cocaine-exposure.

Alcoholism↗

PubMed2003

Auditory evoked potentials from the cortex: audiology applications.

PURPOSE OF REVIEW: The audiological applications of cortical auditory evoked potentials are reviewed. Cortical auditory evoked potentials have some advantages compared with more commonly used techniques such as the auditory brainstem response, because they are more closely tied to perception and can be evoked by complex sounds such as speech. These response characteristics suggest that these potentials could be used clinically in the estimation of threshold and also to assess speech discrimination and perception. RECENT FINDINGS: Clinical uses of auditory evoked potentials include threshold estimation and their use as an electrophysiological index of auditory system development, auditory discrimination and speech perception, and the benefits from cochlear implantation, auditory training, or amplification. SUMMARY: Cortical auditory evoked potentials obtained in passively alert adults have a remarkably high correspondence with perceptual threshold. Acoustic features of complex sounds may be reflected in the waveform and latency of these potentials and so might be used to determine the integrity of neural encoding for such features and thus contribute to speech perception assessment. MMN and P3 have been used to discern discrimination abilities among groups of normal-hearing and hearing-impaired individuals; however, their sensitivity and specificity for testing an individual's abilities has not yet been established. Cortical auditory potentials are affected by listening experience and attention and so could be used to gauge the effects of aural habilitation. The presence of cortical potentials in children with auditory neuropathy appears to indicate residual hearing abilities. Parametric and developmental research is needed to further establish these applications in audiology.

Audiology↗

PubMed2002

Speech perception and cortical event related potentials in children with auditory neuropathy.

OBJECTIVES: 1) To investigate the unaided and aided speech perception abilities of children with auditory neuropathy (AN) and to compare their performance to children with sensorineural hearing loss. 2) To establish whether cortical event related potentials (ERPs) could be recorded in children with AN, and to determine the relationship between the presence of these responses and speech perception. DESIGN: Unaided and aided speech perception assessments (PBK words), and cortical-ERP testing was carried out in a group of 18 children with AN. Data also were obtained from a cohort of age and hearing level matched children with sensorineural hearing loss. RESULTS: The speech perception performance of the 15 children with AN able to complete a PBK-word assessment, fell into two distinct categories. The children either showed no open-set speech perception ability (7/15 cases), or performance levels similar to their sensorineural counterparts (8/15 cases). Approximately 50% of children with AN showed ERPs of normal latency, amplitude and morphology. In all cases, response presence (at normal latencies) was consistent with reasonable speech perception ability, and response absence was consistent with negligible speech perception. CONCLUSIONS: In approximately 50% of children with auditory neuropathy, the provision of amplification results in significant open-set speech perception improvements. The results confirm the previously published reports that speech perception ability cannot be reliably estimated from the behavioral audiogram in children with AN. Obligatory ERP test results may offer a means of predicting perceptual skills in newly diagnosed youngsters as the presence of ERPs (with age-appropriate latency and morphology) was correlated with significant open set speech perception abilities and amplification benefit. The absence of the ERP in contrast, indicated profound hearing disability evidenced by profound hearing loss and/or extremely poor speech perception.

Adolescent↗

PubMed2002

The auditory steady-state response: comparisons with the auditory brainstem response.

Two studies are reported in which the threshold estimates from auditory steady-state response (ASSR) tests are compared to those of click- or toneburst-evoked auditory brainstem responses (ABRs). The first, a retrospective review of 51 cases, demonstrated that both the click-evoked ABR and the ASSR threshold estimates in infants and children could be used to predict the pure-tone threshold. The second, a prospective study of normal-hearing adults, provided evidence that the toneburst-evoked ABR and the modulated tone-evoked ASSR thresholds were similar when both were detected with an automatic detection algorithm and that threshold estimates varied with frequency, stimulus rate, and detection method. The lowest thresholds were obtained with visual detection of the ABR. The studies illustrate that ASSRs can be used to estimate pure-tone threshold in infants and children at risk for hearing loss and also in normal-hearing adults.

Adult↗

PubMed2002

The auditory steady-state response: full-term and premature neonates.

Two studies were aimed at developing the auditory steady-state response (ASSR) for universal newborn hearing screening. First, neonates who had passed auditory brainstem response, transient evoked otoacoustic emission, and distortion-product otoacoustic emission tests were also tested with ASSRs using modulated tones that varied in frequency and level. Pass rates were highest (> 90%) for amplitude-modulated tones presented at levels > or = 69 dB SPL. The effect of modulation frequency on ASSR for 500- and 2000-Hz tones was evaluated in full-term and premature infants in the second study. Full-term infants had higher pass rates for 2000-Hz tones amplitude modulated at 74 to 106 Hz compared with pass rates for a 500-Hz tone modulated at 58 to 90 Hz. Premature infants had lower pass rates than full-term infants for both carrier frequencies. Systematic investigation of ASSR threshold and the effect of modulation frequency in neonates is needed to adapt the technique for screening.

Auditory Perception↗

PubMed2002

The auditory steady-state response: clinical observations and applications in infants and children.

Two studies illustrate the use of the auditory steady-state response (ASSR) in the pediatric clinical audiology setting. A protocol for estimating bone-conduction thresholds from ASSR was developed. Bone-conducted narrow-band noise was used to mask the ASSR for a 1.0-kHz modulated tone. The amount of bone-conducted noise needed to mask the ASSR may distinguish between infants and children with conductive hearing losses and those with sensory losses. The amount of bone-conducted noise may also be used to estimate bone-conduction thresholds; however, the accuracy of this technique needs verification with behavioral methods to determine thresholds for bone-conducted pure tones in infants. When ASSR tests are used as part of the diagnostic evaluation for infants and children at risk for hearing loss, the results yield information about the audiometric contour and residual hearing, which aid in treatment and habilitation decisions.

Acoustic Impedance Tests↗