Biomedical subjects

A Durieux-Smith

Publications and source records attributed to A Durieux-Smith.

At least 19 recordsLinked to original sources

PubMed1998

Objective evaluation of aided thresholds using auditory steady-state responses.

Auditory steady-state responses to amplitude-modulated tones with modulation frequencies between 80 and 105 Hz can be recorded when multiple stimuli are presented simultaneously through a soundfield speaker and amplified using a hearing aid. Responses were recorded at carrier frequencies of 500, 1000, 2000, and 4000 Hz in a group of 35 hearing-impaired children using hearing aids. The physiologic responses were recorded at intensities close to the behavioral thresholds for sounds in the aided condition, with average differences between the physiologic and behavioral thresholds of 17, 13, 13, and 16 dB for carrier frequencies 500, 1000, 2000, and 4000 Hz. The technique shows great promise as a way to assess aided thresholds objectively in subjects who cannot reliably respond on behavioral testing.

Audiometry, Pure-Tone↗

PubMed1996

Frequency-specific audiometry using steady-state responses.

OBJECTIVE: To evaluate the audiometric usefulness of steady-state responses to multiple simultaneous tones, amplitude-modulated at 75 to 110 Hz. DESIGN: Steady-state responses to multiple tones amplitude-modulated at different rates between 75 and 110 Hz and presented simultaneously were recorded at different intensities in normal adults, well babies, normal adults with simulated hearing loss, and adolescents with known hearing losses. Response thresholds were compared with behavioral thresholds. RESULTS: In normal adults the thresholds for steady-state responses to tones of 0.5, 1, 2, and 4 kHz were 14 +/- 11, 12 +/- 11, 11 +/- 8, and 13 +/- 11 dB, respectively, above behavioral thresholds for air-conducted stimuli, and 11 +/- 5, 14 +/- 8, 9 +/- 8, and 10 +/- 10 dB above behavioral thresholds for bone-conducted stimuli. In well babies tested in a quiet environment, the thresholds were 45 +/- 13, 29 +/- 10, 26 +/- 8, and 29 +/- 10 dB SPL. In adolescents with known hearing losses, the steady-state responses thresholds predict behavioral thresholds with correlation coefficients (r) of 0.72, 0.70, 0.76, and 0.91 at 0.5, 1, 2, and 4 kHz, respectively. CONCLUSION: Steady-state responses to tone amplitude-modulated at 75 to 110 Hz can be used for frequency-specific objective audiometry. The multiple-stimulus technique allows thresholds to be estimated for eight different stimuli at the same time.

Adolescent↗

PubMed1995

Auditory steady-state responses to tones amplitude-modulated at 80-110 Hz.

Steady-state responses can be recorded from the human scalp in response to tones that are sinusoidally modulated in amplitude at rates between 60 and 120 Hz. For 60 dB SPL 1000-Hz tones the maximum baseline-to-peak amplitude of about 0.06 microV occurs for modulation rates between 80 and 95 Hz. The phase of the response does not change with modulation depths greater than 25% and the amplitude saturates at modulation depths greater than 50%. The presence or absence of a response can be accurately determined by frequency-domain statistics and the response becomes clearly recognizable at intensities that are 16 +/- 8 dB above behavioral thresholds. With increasing intensity the response increases in amplitude at 1.9 nV/dB until an intensity of 70 dB SPL. As the intensity increases above 70 dB SPL the response increases in amplitude more rapidly at 7.8 nV/dB (at 1000 Hz) and contains significant energy at harmonics of the modulation frequency. This second stage of the intensity function is more prominent for stimuli with lower carrier frequencies (500 more than 1000 more than 2000 Hz) and is attenuated by high-pass masking. These steady-state responses should be helpful in evaluating human auditory physiology and in objective audiometry.

Adult↗

PubMed1994

Recording auditory brainstem responses from infants.

Auditory brainstem responses (ABRs) can be reliably recorded from infants in the first few months of life. Since they are normally recognizable down to intensities that are 30 dB above normal hearing thresholds, ABRs elicited by clicks are useful in screening for hearing-impairment in infancy. The ABRs can also provide further diagnostic information about the hearing losses that are detected by screening: the threshold for the response represents a reasonable estimate of the severity of the hearing loss; bone-conduction studies can assess the extent of a conductive loss; and frequency-specific techniques can evaluate hearing thresholds at different frequencies. At present, ABRs are mainly used for screening infants who have been treated in neonatal intensive care units. Because the majority of infants with hearing impairment are not seen in these units, it might be worthwhile to use ABRs in a more widespread screening program.

Evoked Potentials, Auditory, Brain Stem↗

PubMed1991

Probe tube microphone measures of loudness discomfort levels in children.

Loudness discomfort levels (LDLs) have been advocated as a means for selecting the SSPL90 setting of an individual's hearing aid. Kawell, Kopun, and Stelmachowicz (Ear Hear 1988; 9: 133-136) recently developed a procedure to measure LDLs in children. Several procedural cautions, involving the hearing aid stimulus delivery and sound field calibration, have been noted with this method. As a means of overcoming these problems, a new method utilizing insert earphone derived stimuli delivered to a child's ear-mold with probe tube microphone monitoring of real-ear sound pressure level was explored. Twenty children, aged 7 to 14 years, served as subjects. The advantage of the present method lies in the procedural conveniences and the ability to compare real-ear audiometric measures and hearing aid performance.

Adolescent↗

PubMed1991

Prognostic validity of brainstem electric response audiometry in infants of a neonatal intensive care unit.

This study compared the results of brainstem electric response audiometry (BERA) in infants of a neonatal intensive care unit to those obtained on the same children with pure-tone audiometry at 3 years of age. Six hundred children were initially tested in infancy, and complete follow-up information was obtained on 333. In 297 (89%) the BERA results accurately predicted the hearing status at the age of 3 years. Twenty-nine (9%) of the discrepancies were related to conductive hearing losses: 17 patients with a conductive hearing loss in the first few months of life had normal hearing at 3 years, and 12 patients normal in infancy had a conductive loss at 3 years. Two patients evaluated as a sensorineural hearing loss by BERA had normal hearing. These may have been due to a conductive loss. Six patients assessed as normal by BERA had significant hearing losses at the age of 3 years. Five of these had normal hearing at one frequency between 1,000 and 4,000 Hz. The sixth may have developed a sensorineural hearing loss after birth.

Audiometry, Evoked Response↗

PubMed1991

Randomized, controlled trial comparing long-term sulfonamide therapy to ventilation tubes for otitis media with effusion.

Several studies have indicated that either the surgical insertion of ventilation tubes (VTs) or long-term treatment with sulfonamide-based antibacterials is effective in the management of otitis media with effusion (OME; otherwise known as serous otitis media, secretory otitis media, and glue ear) when compared with a no-treatment control or placebo. This controlled trial is the first to compare directly the effectiveness of these two treatments for long-standing OME. Outcome variables are treatment success rates, hearing thresholds, recurrent acute otitis media episodes, and side effects of medication or complications of VT placement. One hundred twenty-five children (aged 2.5 to 7 years) who met the usual indications for surgery (long-standing [greater than 3 months] OME and conductive hearing loss) were randomly assigned to "medical" treatment (sulfisoxazole 75 mg/kg per day for 6 months) or "surgical" treatment (bilateral insertion of VTs). Subjects underwent pure-tone audiometry (500, 1000, 2000, 4000 Hz) and otomicroscopic examination at 2, 4, 6, 12, and 18 months. A significantly greater proportion of medical subjects (67%) than surgical subjects (48%) were treatment failures at 6, 12, or 18 months (P = .0208). Surgical subjects had significantly better hearing at 2 and 4 months (P values less than .01) but not at 6, 12, and 18 months (P values greater than .2). A significantly greater proportion of surgical subjects (50%) experienced complications of treatment than did medical subjects (9%) (P less than .001). Thirty-three percent of candidates for VT placement did not require surgery when treated with a 6-month course of sulfisoxazole.(ABSTRACT TRUNCATED AT 250 WORDS)

Audiometry, Pure-Tone↗

PubMed1990

Critical differences in aided sound field thresholds in children.

Variability of aided sound field thresholds (ASFTs) was examined in 30 children comprising two age groups (5-9 and 10-14 years). Test-retest ASFTs were collected at six frequencies (250, 500, 1000, 2000, 3000, and 4000 Hz). No statistically significant difference was found in mean test and retest ASFTs between the two groups (p greater than .05). Test-retest difference data from both groups of children were combined and used to generate critical differences (in dB) for two ASFTs. At a 95% confidence level, two ASFTs would have to differ by more than 10 dB across signal test frequencies to attain statistical significance. In clinical decision-making, if one accepts smaller differences in ASFTs as statistically significant, larger probabilities of error must be assumed.

Acoustics↗

PubMed1990

Bayley developmental performance at two years of age of neonates at risk for hearing loss.

Of 306 infants in a neonatal intensive care unit (NICU) screened for hearing-loss before discharge with both the 'Crib-O-Gram' (COG) and brainstem auditory evoked responses (BAER), 122 failed either or both tests. These infants were then tested on the Bayley Scales at approximately 24 months corrected age, together with 25 infants who had passed both tests and 25 non-NICU infants from a general medical follow-up clinic. Compared with BAERs, the COG was found to be inadequate in detecting mild hearing loss, but its sensitivity increased with more severe loss. On the Bayley Scales, infants who had failed the BAER had lower scores than those who had passed, but for those who had passed the BAER, there was no difference in development between those who had failed and passed the COG.

Brain Damage, Chronic↗

PubMed1990

Thresholds for short-latency auditory-evoked potentials to tones in notched noise in normal-hearing and hearing-impaired subjects.

The thresholds for the short-latency auditory evoked potentials (SLAEPs) to short-duration tones presented in notched-noise masking were evaluated in 20 normal-hearing and 20 hearing-impaired subjects. The differences (dB) between these thresholds (dB nHL) and the pure-tone behavioral thresholds (dB HL) across all 40 subjects were 11.6, 6.1, 6.3 and 0.8 dB for 500, 1,000, 2,000 and 4,000 Hz, respectively. These differences were significantly smaller for the hearing-impaired subjects than for the normal-hearing subjects. Ninety-eight percent of the SLAEP threshold estimations were within 30 dB of the subjects' pure-tone behavioral thresholds and 91% were within 20 dB.

Adolescent↗

PubMed1988

Auditory evoked potentials in the assessment of hearing.

The auditory evoked potentials are the best available technique for identifying infants with a hearing impairment before the age of 6 months. They are also very important in the evaluation of patients with suspected retrocochlear hearing loss. New developments may soon allow the determination of hearing thresholds at different frequencies and a more accurate assessment of patients with central auditory dysfunction.

Audiometry, Pure-Tone↗

PubMed1988

The contribution of brainstem electric response audiometry (BERA) to the evaluation and management of infants with cleft palate.

In the three-year period ending December 1986, 31 infants followed by the Cleft Palate Team of our institution were evaluated with BERA one or more times. Seventy-four percent presented auditory threshold elevation on initial examination; none was observed to resolve spontaneously in the first year of life. Myringotomy and tympanostomy tube insertion normalized auditory thresholds effectively in most children with serous otitis media. In a few cases, however, recovery required several months. BERA can assist the early detection of children with sensorineural hearing loss. It may also be valuable as an additional consideration in selecting treatment of serous otitis media in these children. Precise guidelines as to the ideal time to perform tympanostomy requires further substantiation of the effects of early hearing loss on speech and language development.

Audiometry, Evoked Response↗

PubMed1987

Brainstem electric-response audiometry in infants of a neonatal intensive care unit.

Brainstem electric-response audiometry was used to assess the auditory function of 600 infants from a neonatal intensive care unit. Two groups of children were tested, one group as inpatients prior to discharge with a mean age at test of 39.4 weeks and one group as outpatients with a mean age at test of 55.4 weeks. Our results indicate that testing infants when they are older will reduce the incidence of failure on the initial evaluation and will reduce the identification of transient hearing losses which resolve spontaneously. Our results also indicate that a threshold of 30 dB nHL or less is probably normal and that some infants with a threshold of 40 dB nHL at first test require otological or audiological management.

Audiometry, Evoked Response↗

PubMed1985

Auditory brainstem responses to clicks in neonates.

Normative data are required when interpreting brainstem electric response audiometry results. An abnormal auditory brainstem response (ABR) cannot be identified without knowledge of the normal ABR and the variability associated with technical and physiological factors. Normative data obtained from babies in a neonatal intensive care unit in response to click stimulation are presented in this paper.

Acoustic Stimulation↗

PubMed1985

Incidence of hearing loss in high risk and intensive care nursery infants.

The incidence of hearing impairment in high risk infants is summarized for five programs which use brainstem electric response audiometry (BERA) to detect hearing loss in this population. Programs are compared with respect to the following variables which may affect reported incidence figures: population characteristics, stimulus and recording parameters, criteria for failure on the initial BERA test, and follow-up protocols. Between 10-30% of these infants fail an initial BERA test, with initial failure rate largely dependent on the failure criteria used. Approximately 10% will continue to show some degree of hearing impairment on follow-up tests at 2-5 months of age. Between 2-4% will have a moderate to profound bilateral sensorineural hearing loss requiring amplification and habilitation.

Acoustic Stimulation↗

PubMed1985

Auditory brainstem response audiometry in neonatal hydrocephalus.

Sixteen hydrocephalic NICU babies and 16 age-matched, non-hydrocephalic NICU babies were tested with BERA. The latency and amplitude of waves I and V were compared between groups. Both waves were longer in latency and smaller in amplitude in the hydrocephalic group. The I-V latency interval was within normal limits, but the V/I amplitude ratio was significantly smaller. The reduced amplitude of wave V was the most noticeable ABR abnormality. A total of 11 hydrocephalic babies showed responses that were considered abnormal in amplitude, with all but one having an elevated ABR threshold in at least one ear. These threshold elevations may reflect a neurological condition rather than a peripheral hearing loss.

Audiometry, Evoked Response↗

PubMed1985

Comparison of auditory brainstem response and behavioral screening in neonates.

This paper reports on two studies, one in Halifax and the other in Ottawa, which compared behavioral methods and BERA in the screening of hearing loss in neonates. The Halifax study used BERA as the screening procedure for infants of a neonatal intensive care unit (NICU) and as a supplementary procedure to behavioral screening test for non-NICU but "at risk" infants. The results of this study indicate false positive rates with the behavioral test of 86.1 and 50.5% for NICU and at risk groups respectively. The Ottawa study evaluated the Crib-o-gram as a screening test for NICU infants using BERA as the standard. The results of this study indicated that approximately one third of babies with normal BERA thresholds failed Crib-o-gram screening and that Crib-o-gram could identify moderately/severe losses.

Acoustic Stimulation↗

PubMedDate not supplied

Neonatal auditory brain stem responses from ipsilateral and contralateral recording montages.

Ipsilateral and contralateral auditory brain stem responses were recorded from both ears of 10 neonates between 37 and 43 weeks from conception with normal auditory brain stem function. The most prominent component of the contralateral response was a forehead positive deflection occurring 0.3 millisecond before the ipsilateral wave III followed by two forehead negative waves, the latter present at the same latency as the ipsilateral wave V. The amplitude of the contralateral response was small: at 30 dB nHL only 7 of the 20 ears showed clear responses from this montage. The morphology of the neonatal contralateral response is thus considerably different than the ipsilateral, unlike the adult. A neonate could be mistakenly diagnosed as hearing impaired or neurologically involved if the interpretation is based on the contralateral recording.

Audiometry, Evoked Response↗