Tympanometric and Acoustic-Reflex Studies in Neonates

1985 ◽  
Vol 28 (2) ◽  
pp. 265-272 ◽  
Author(s):  
Barbara H. Sprague ◽  
Terry L. Wiley ◽  
Robert Goldstein
Keyword(s):  
Broadband Noise ◽  
Acoustic Reflex ◽  
Probe Tone ◽  
Acoustic Reflexes ◽  
Probe Frequency ◽  
High Age ◽  
Normal Neonates ◽  
Age Change

Tympanograms and acoustic reflexes for a broadband noise and for a 1000-Hz tone were measured in normal neonates. Notched tympanograms were typical of neonatal ears for a 220-Hz probe tone. A single-peaked tympanogram was most characteristic for a probe frequency of 660 Hz. Ipsilateral and contralateral acoustic reflexes were present more frequently for a 660-Hz probe tone compared to a 220-Hz probe tone, but acoustic-reflex thresholds were not significantly different between probe tones. As with adults, acoustic-reflex thresholds for the noise were significantly lower than for the tone, and ipsilateral reflex thresholds were lower than contralateral reflex thresholds. Reliability of acoustic-reflex and tympanometric measures was high. Age change from 2 to 4 days had no significant effect on tympanometric or acoustic-reflex characteristics. There was no apparent relation between tympanometric pattern and acoustic-reflex characteristics.

Newborn Acoustic Reflexes to Noise and Pure-Tone Signals

1982 ◽  
Vol 25 (3) ◽  
pp. 383-387 ◽  
Author(s):  
Michael J. Bennett ◽  
Lynn A. Weatherby
Keyword(s):  
Pure Tone ◽  
Broadband Noise ◽  
Acoustic Reflex ◽  
Acoustic Reflexes ◽  
Auditory Response ◽  
Reflex Activation ◽  
The Mean ◽  
Reflex Threshold ◽  
Filtered Noise ◽  
High Pass

A variable-frequency probe-tone acoustic-impedance bridge has been developed to enable an artifact-free pure-tone acoustic reflex study to be carried out on neonates. Contralateral reflex thresholds for pure tones, broadband noise, and filtered noise were measured in 28 newborns aged 4–8 days. The mean reflex threshold for the broadband noise was 73 dB SPL, 4 dB lower than the reflex threshold for the 2600-Hz low- and high-pass noise bands. Reflex activation at 500, 1000, 2000, and 4000 Hz gave responses that closely followed the normal adult pattern although reflex thresholds were approximately 10 dB higher. Two infants failed to demonstrate reflexes. One of these failed a behavioral-response test using the Auditory Response Cradle and was found to have mild jaundice. The second infant passed the behavioral test and had measurable reflexes 5 weeks later. A third baby with elevated reflex thresholds also was jaundiced but had normal behavioral responses and was discharged. Discussion of these results emphasizes their value to those engaged in neonatal auditory assessment.

The Effects of Probe-Tone Frequency on the Acoustic-Reflex Growth Function

2003 ◽  
Vol 14 (02) ◽  
pp. 109-118 ◽  
Author(s):  
John J. Lutolf ◽  
Honor O'Malley ◽  
Shlomo Silman
Keyword(s):  
Correlation Coefficients ◽  
Growth Function ◽  
Acoustic Reflex ◽  
Tone Frequency ◽  
Probe Tone ◽  
Growth Functions ◽  
Polynomial Coefficients ◽  
Acoustic Reflexes ◽  
Pure Tones ◽  
High Frequency Probe

Acoustic-reflex growth functions (ARGFs) were obtained from 20 normal-hearing listeners, Contralateral acoustic reflexes (ARs) were elicited with pure tones of 2000 Hz. The magnitude of changes in static compliant susceptance (BA) and conductance (GA) were monitored with probe-tone frequencies of 226 Hz, 678 Hz and 1000 Hz. ARGFs were obtained with six combinations of probe-tone frequency/admittance component: 226 Hz BA, 226 Hz GA, 678 Hz BA, 678 Hz GA, 1000 Hz BA, and 1000 Hz GA. Peak conductance (GA) and susceptance (BA) ARs were largest within the 678 Hz GA and 1000 Hz BAARGFs, respectively. Among high-frequency probe tones, the patterns of AR growth were larger and less variable for the 678 Hz GA ARGF and the 1000 Hz BA ARGF as determined by the magnitude of their linear (b1) and quadratic (b2) polynomial coefficients and the value of their squared correlation coefficients (R2).

scholarly journals Effect of age on acoustic reflex thresholds in neonates and infants with normal hearing

2021 ◽  
Vol 7 (5) ◽  
pp. 746
Author(s):  
Dipti Gupta ◽  
C. S. Vanaja
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Clinical Population ◽  
Repeated Measure ◽  
Acoustic Reflex ◽  
Probe Tone ◽  
Acoustic Reflexes ◽  
Newborn Hearing ◽  
Neonates And Infants ◽  
Effect Of Age

<p><strong>Background:</strong> High frequency (1000 Hz) probe tone holds substantial promise for carrying out acoustic reflexes in neonates and infants. A limited number of studies indicates that acoustic reflex thresholds (ART) also change significantly with age as the newborn hearing system matures. However, there is a need for obtaining more data before using it in a clinical population. The aim was to investigate effect of age of infants on ARTs. Effect of activator signal was also explored.  <strong></strong></p><p><strong>Methods:</strong> ARTs were monitored using a 1 kHz probe tone for the 500 Hz, 1 kHz, 2 kHz, and 4 kHz pure tone activators in neonates and infants in the age range of 6 to 8 weeks were analysed.</p><p><strong>Results</strong>: The mean ARTs for neonates were lower compared to infants. Results of repeated measure ANOVA showed that there was a statistically significant age effect. Also, ARTs for high frequency activator signals were significantly higher than the ARTs for low frequency signals.</p><p><strong>Conclusions:</strong> The acoustic reflexes can be elicited for 500, 1000, 2000, and 4000 Hz when monitored using a 1000 Hz probe tone. There is an effect of age and activator signal on the acoustic reflex threshold. The data obtained in the present study can serve as normative for 0-1-week neonates and 6-8-weeks infants.</p>

scholarly journals Direction of susceptance and conductance acoustic reflexes at high probe frequencies

1994 ◽  
Vol 41 (1) ◽  
Author(s):  
Louise Reynolds ◽  
Lucille P. Morton
Keyword(s):  
Theoretical Models ◽  
Ossicular Chain ◽  
Baseline Condition ◽  
Acoustic Reflex ◽  
Low Frequencies ◽  
Transmission Properties ◽  
Intensity Range ◽  
Acoustic Reflexes ◽  
Probe Frequency

Previous investigations have shown that for low probe frequencies (220 and 660 Hz) the direction of susceptance and conductance reflexes is related to baseline transmission properties. Previously documented reflex patterns, caused by the stiffening of the ossicular chain, are characterised by decreases in both components at 220 Hz (-B-G) and increases in susceptance and decreases in conductance (+B-G) at 660 Hz. In the present study, the direction of susceptance and conductance acoustic reflexes was investigated at a probe frequency of 1000 Hz, where ears are expected to be less stiffness dominated than at the low frequencies, and for which there is little description of reflex patterns in the published literature. The pattern of ipsilateral susceptance and conductance reflexes from 30 normal ears was recorded across a wide intensity range at this probe frequency for three stimulus frequencies (0.5, 1 and 2 kHz). Reflexes were classified as either increases (+) or decreases (-) for each component, at threshold and at suprathreshold intensity levels. Ears were grouped according to transmission properties at 1000 Hz, and reflex patterns observed within each group of subjects were examined. Patterns observed in these subjects at the 1000 Hz probe frequency included: +B-G; +B+G; -B+G and -B-G. There appeared to be a relationship between baseline transmission and reflex patterns. Further, patterns appear to be consistent with theoretical models of the effect of the acoustic reflex, particularly for ears where stiffness is significant in the baseline condition. The effect of the reflex for mass dominated systems requires further investigation.

Acoustic-Reflex Dynamics for Pulsed Signals

1978 ◽  
Vol 21 (2) ◽  
pp. 295-308
Author(s):  
Terry L. Wiley ◽  
Raymond S. Karlovich
Keyword(s):  
Duty Cycle ◽  
Acoustic Impedance ◽  
Normal Hearing ◽  
Broadband Noise ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Acoustic Reflex ◽  
Stapedius Muscle ◽  
Duty Cycles

Contralateral acoustic-reflex measurements were taken for 10 normal-hearing subjects using a pulsed broadband noise as the reflex-activating signal. Acoustic impedance was measured at selected times during the on (response maximum) and off (response minimum) portions of the pulsed activator over a 2-min interval as a function of activator period and duty cycle. Major findings were that response maxima increased as a function of time for longer duty cycles and that response minima increased as a function of time for all duty cycles. It is hypothesized that these findings are attributable to the recovery characteristics of the stapedius muscle. An explanation of portions of the results from previous temporary threshold shift experiments on the basis of acoustic-reflex dynamics is proposed.

Acoustic Reflex Testing in Neonatal Hearing Screening and Subsequent Audiological Evaluation

2018 ◽  
Vol 61 (7) ◽  
pp. 1784-1793
Author(s):  
Lilian Cássia Bórnia Jacob-Corteletti ◽  
Eliene Silva Araújo ◽  
Josilene Luciene Duarte ◽  
Fernanda Zucki ◽  
Kátia de Freitas Alvarenga
Keyword(s):  
Risk Factors ◽  
Birth Weight ◽  
Gestational Age ◽  
Pure Tone ◽  
Broadband Noise ◽  
Acoustic Reflex ◽  
Group I ◽  
Group Ii ◽  
Gestational Age At Birth ◽  
Age At Birth

Purpose The aims of the study were to examine the acoustic reflex screening and threshold in healthy neonates and those at risk of hearing loss and to determine the effect of birth weight and gestational age on acoustic stapedial reflex (ASR). Method We assessed 18 healthy neonates (Group I) and 16 with at least 1 risk factor for hearing loss (Group II); all of them passed the transient evoked otoacoustic emission test that assessed neonatal hearing. The test battery included an acoustic reflex screening with activators of 0.5, 1, 2, and 4 kHz and broadband noise and an acoustic reflex threshold test with all of them, except for the broadband noise activator. Results In the evaluated neonates, the main risk factors were the gestational age at birth and a low birth weight; hence, these were further analyzed. The lower the gestational age at birth and birth weight, the less likely that an acoustic reflex would be elicited by pure-tone activators. This effect was significant at the frequencies of 0.5, 1, and 2 kHz for gestational age at birth and at the frequencies of 1 and 2 kHz for birth weight. When the broadband noise stimulus was used, a response was elicited in all neonates in both groups. When the pure-tone stimulus was used, the Group II showed the highest acoustic reflex thresholds and the highest percentage of cases with an absent ASR. The ASR threshold varied from 50 to 100 dB HL in both groups. Group II presented higher mean ASR thresholds than Group I, this difference being significant at frequencies of 1, 2, and 4 kHz. Conclusions Birth weight and gestational age at birth were related to the elicitation of the acoustic reflex. Neonates with these risk factors for hearing impairment were less likely to exhibit the acoustic reflex and had higher thresholds.

scholarly journals Effect of Intensity Level and Speech Stimulus Type on the Vestibulo-Ocular Reflex

2019 ◽  
Vol 30 (09) ◽  
pp. 792-801 ◽  
Author(s):  
Mary Easterday ◽  
Patrick N. Plyler ◽  
James D. Lewis ◽  
Steven M. Doettl
Keyword(s):  
Repeated Measures ◽  
Vestibular Nuclei ◽  
Auditory Stimulation ◽  
Broadband Noise ◽  
Speech Stimulus ◽  
Intensity Level ◽  
Acoustic Reflex ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Acoustic Reflex Threshold

AbstractAccurate vestibulo-ocular reflex (VOR) measurement requires control of extravestibular suppressive factors such as visual fixation. Although visual fixation is the dominant suppressor and has been extensively studied, the mechanisms underlying suppression from nonvisual factors of attention and auditory stimulation are less clear. It has been postulated that the nonvisual suppression of the VOR is the result of one of two mechanisms: (1) activation of auditory reception areas excites efferent pathways to the vestibular nuclei, thus inhibiting the VOR or (2) cortical modulation of the VOR results from directed attention, which implies a nonmodality-specific process.The purpose of this research was to determine if the VOR is affected by the intensity level and/or type of speech stimulus.A repeated measures design was used. The experiment was single-blinded.Participants included 17 adults (14 females, three males) between the ages of 18–34 years who reported normal oculomotor, vestibular, neurological, and musculoskeletal function.Each participant underwent slow harmonic acceleration testing in a rotational chair. VOR gain was assessed at 0.02, 0.08, and 0.32 Hz in quiet (baseline). VOR gain was also assessed at each frequency while a forward running speech stimulus (attentional) or a backward running speech stimulus (nonattentional) was presented binaurally via insert earphones at 42, 62, and 82 dBA. The order of the conditions was randomized across participants. VOR difference gain was calculated as VOR gain in the auditory condition minus baseline VOR gain. To evaluate auditory efferent function, the medial olivocochlear reflex (MOCR) was assayed using transient-evoked otoacoustic emissions (right ear) measured in the presence and absence of broadband noise (left ear). Contralateral acoustic reflex thresholds were also assessed using a broadband noise elicitor. A three-way repeated measures analysis of variance was conducted to evaluate the effect of frequency, intensity level, and speech type on VOR difference gain. Correlations were conducted to determine if difference gain was related to the strength of the MOCR and/or to the acoustic reflex threshold.The analysis of variance indicated that VOR difference gain was not significantly affected by the intensity level or the type of speech stimulus. Correlations indicated VOR difference gain was not significantly related to the strength of the MOCR or the acoustic reflex threshold.The results were in contrast to previous research examining the effect of auditory stimulation on VOR gain as auditory stimulation did not produce VOR suppression or enhancement for most of the participants. Methodological differences between the studies may explain the discrepant results. The removal of an acoustic target from space to attend to may have prevented suppression or enhancement of the VOR. Findings support the hypothesis that VOR gain may be affected by cortical modulation through directed attention rather than due to activation of efferent pathways to the vestibular nuclei.

Acoustic reflex measures at high probe frequency: a phasor diagram approach

1995 ◽  
Vol 29 (3) ◽  
pp. 144-152 ◽  
Author(s):  
Louise Reynolds ◽  
Lucille P. Morton
Keyword(s):  
Acoustic Reflex ◽  
Probe Frequency ◽  
Diagram Approach

Acoustic-Reflex Dynamics and the Loudness-Discomfort Level

1985 ◽  
Vol 50 (1) ◽  
pp. 14-20 ◽  
Author(s):  
Donna G. Greenfield ◽  
Terry L. Wiley ◽  
Michael G. Block
Keyword(s):  
Acoustic Impedance ◽  
Normal Hearing ◽  
Broadband Noise ◽  
Impedance Change ◽  
Acoustic Reflex ◽  
Good Reliability ◽  
Large Variability ◽  
Growth Functions ◽  
Within Subjects ◽  
Relative Change

Acoustic-reflex growth functions and Loudness-Discomfort Level (LDL) measures were obtained for 15 normal-hearing subjects. The hypothesis that signals considered uncomfortably loud occur at intensity levels that produce proportionately equal acoustic-reflex magnitudes was evaluated. Individual reflex growth functions were measured as a function of activator SPL for a 1000-Hz tone, a 4000-Hz tone, and a broadband noise. These growth functions were measured within subjects (two trials) and across subjects in terms of (a) percentage acoustic-impedance change at LDL, (b) percentage acoustic-reactance change at LDL, (c) acoustic impedance at LDL, (d) relative change in acoustic impedance at LDL, and (e) ratio of static acoustic impedance to change in acoustic impedance at LDL. Although the loudness and acoustic-reflex measures demonstrated good reliability across trials, the data showed large variability across subjects and did not support the experimental hypothesis. It was concluded, therefore, that the use of acoustic-reflex measures in the estimation of an individual's LDL is unwarranted.

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