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Y S Sininger

Publications and source records attributed to Y S Sininger.

25 records · Page 2Linked to original sources
PubMed1996

Hearing threshold as measured by auditory brain stem response in human neonates.

OBJECTIVES: This article evaluates the concept of auditory threshold and discusses the limitations of assessing threshold in human neonates. The advantages and limitations of assessing neonatal threshold by means of auditory brain stem response (ABR) are discussed, and data from several studies of newborn ABR threshold are compared. The authors report data from their own study designed to compare adult and neonatal ABR threshold using tonal stimuli. EXPERIMENTAL DESIGN: Several studies are compared. Data from the authors are ABR thresholds for tone bursts of 0.5, 1.5, 4, and 8 kHz, determined from 2-channel recordings in full-term neonates and adults. Stimuli were calibrated in SPL by means of a probe microphone inserted into the ear canal along with the insert transducer of each subject. RESULTS: All studies find a degree of threshold elevation in neonates relative to adult threshold. Neonatal ABR thresholds from our laboratory for stimuli from 500 through 8000 Hz are elevated relative to adult thresholds by 5 to 25 dB. Threshold elevation in our data and in other studies has found that neonatal ABR thresholds to high-frequency stimuli show the largest elevation relative to adults and low-frequency stimuli the most mature. CONCLUSIONS: Thresholds of neonates, as measured by the ABR, are immature especially for high-frequency stimuli. Proper stimulus calibrations, which removes the influence of ear canal resonance, are important for comparisons of data across age groups. Developmental differences in the conductive mechanism and neural immaturity are the most harmonious explanations for elevation of neonatal ABR thresholds.

Adult↗
PubMed1995

Filtering and spectral characteristics of averaged auditory brain-stem response and background noise in infants.

Filtering of electrode-recorded activity before averaging is used in evoked-potential measurements to reduce background noise under the assumption that unwanted spectral components will be suppressed without substantially altering neural activity. Desired filter characteristics depend on signal and noise spectra and filter choice can affect the validity and efficiency of ABR measurement. Spectral characteristics of the human auditory brain-stem response (ABR) change with subject age and state and with the level and spectrum of the stimulus. Brain-stem evoked potentials from infants comprise greater low-frequency spectral components than do adult ABRs. Physiologic noise can also change with age of the subject. This study compares the effects of 30- and 100-Hz high-pass filters on ABR amplitude and response Fsp in full-term infants. Stimuli used to elicit ABRs are moderate- and low-level clicks and 500-Hz tone bursts. Spectral characteristics of the averaged ABR and the no-stimulus background noise from full-term infants are also characterized. Results indicate that (1) energy in the infant ABR is concentrated below 100 Hz and (2) a high-pass recording filter of 30 Hz reveals a larger-amplitude ABR and enhances the overall signal-to-noise ratio as measured by Fsp as compared to a 100-Hz high pass.

Acoustic Stimulation↗
PubMed1993

Auditory brain stem response for objective measures of hearing.

The auditory brain stem response (ABR) is felt to be an objective technique for predicting hearing thresholds because a voluntary response is not required from the subject. However, determination of ABR threshold can be a subjective process. This article discusses a technique, termed Fsp, which adds objectivity to ABR threshold detection by creating a ratio of signal plus averaged background noise over an estimate of the averaged background noise for any given averaged ABR. Fsp values have an F distribution. Consequently, the confidence of true detection for a given ABR can be determined by comparing its calculated Fsp value to statistical tables. Using a technique such as Fsp not only adds objectivity to ABR threshold detection, but also optimizes test time by allowing the averaging process to stop as soon as the background noise has been reduced and the true neural potential can be judged to be present. The estimate of the background noise can be used as a weighting factor to reduce the influence of noisy segments during the averaging process as well. Using this technique, we have found ABR threshold to be within 5 or 6 dB of psychophysical threshold for like (click) stimuli and, in our pediatric clinic, ABR click thresholds are within 10 dB of puretone average for children with losses ranging from mild to profound.

Acoustic Stimulation↗
PubMed1990

Effect of click polarity on ABR threshold.

This study investigated the effects of click polarity on threshold detectability (threshold level in dB SL) of the auditory brain stem response (ABR). ABRs were obtained from 10 normally hearing adult subjects in response to rarefaction and condensation clicks presented from 0 to 10 dB SL in 2 dB steps. An objective response signal-to-noise estimator, known as Fsp, was the dependent variable. ABR detectability functions (Fsp by dB SL) were not significantly influenced by click polarity. Conclusions can only be drawn for normally hearing adults. For this population, click polarity does not affect threshold detection with the ABR.

Acoustic Stimulation↗
PubMed1989

Memory scanning speed in language-disordered children.

Twelve students from classrooms for children with severe language disorders and 12 age-matched controls were evaluated for short-term memory scanning speed using the Sternberg task. Sets of two, three, and four digits were presented via earphones as memory sets, followed by single-probe digits. Reaction time was measured for a verbal response of "yes" or "no" indicating whether the probe was a member of the initial set. Average per-item scanning speed for the normal children was 66 ms, which was significantly different from the 253-ms average scanning speed of the language-disordered group. Many similarities were noted in the performance of the two groups on the memory scanning task. No differences were found in estimates of encoding and response speed, in percentage of errors or in serial or numerical position effects across groups. Results indicate that children with developmental language disorders may demonstrate reduced processing speed or memory retrieval time, which could contribute to linguistic deficits.

Adolescent↗
PubMed1989

Effects of click rate and electrode orientation on threshold of the auditory brainstem response.

This study evaluated the effects of stimulus presentation rate and electrode orientation on ABR threshold. Six normal-hearing adults served as subjects. ABRs were recorded from three orthogonal electrode pairs in response to click stimuli at rates of 48 and 21/s. Psychophysical thresholds were determined for each of these stimuli, and ABRs were recorded with stimuli between 0 and 10 dB SL in 2-dB steps. A ratio of ABR signal strength to noise variance (Fsp) was the criterion used to define threshold. Specifically, an Fsp value of 2.25, equivalent to a 95% response confidence using 5 and 250 degrees of freedom, was the criterion used to determine response presence within a maximum of 10,000 sweeps per average. Results revealed that, for normal-hearing adult subjects, click rate up to 48/s does not influence the sensation level at which a detectable response can be found, and a nearly vertical electrode orientation is optimal for recording the response at low levels. The predicted difference between psychophysical and ABR thresholds with a vertical electrode orientation, using 10,000 sweeps per average, up to 48 clicks per second, and an Fsp criterion of 2.25 is 4.4 dB.

Auditory Threshold↗