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Contralateral suppression of otoacoustic emissions: input-output functions in neonates.

Campos Ude P, Hatzopoulos S, Kochanek K, Sliwa L, Skarzynski H, Carvallo RM - Med. Sci. Monit. (2011)

Bottom Line: Significant DPOAE amplitude suppression effects were observed at various L2 stimulus levels for both tested frequencies at 2 and 4 kHz.In contrast, the corresponding DPOAE slopes showed various alterations that were not statistically significant.From the available data it is not possible to infer whether the sample size has influenced the obtained results and the study should be repeated with a larger sample size and assessing more frequencies.

View Article: PubMed Central - PubMed

Affiliation: University of São Paulo, São Paulo, Brazil.

ABSTRACT

Background: The literature suggests that contralateral acoustic stimulation (CAS) alters the amplitude of the distortion product otoacoustic emissions (DPOAEs), but it is still unknown whether the DPOAE Input/Output (I/O) functions are also affected. To elucidate this aspect of the DPOAEs, the present study assessed the effects of CAS on DPOAE I/O functions at the frequencies of 2 kHz and 4 kHz, in a sample of term neonatal subjects.

Material/methods: Sixty randomly selected neonates were included in the study. The DPOAE I/O functions were obtained at 2 kHz and 4 kHz, in the presence of a 60 dB SPL broad band-contralateral white noise, using the TDH39 headphones contralaterally. DPOAEs were recorded up to a stimulus level of L2 = 35 dB peSPL.

Results: Significant DPOAE amplitude suppression effects were observed at various L2 stimulus levels for both tested frequencies at 2 and 4 kHz. In contrast, the corresponding DPOAE slopes showed various alterations that were not statistically significant.

Conclusions: The data from the present study show that contralateral acoustic stimulation significantly affects only the amplitude of the DPOAE I/O functions; the slope is affected, but not significantly. This observation can shed light on the nature of CAS, suggesting that the latter is primarily a linear phenomenon without the cochlear compression and non-linear components seen in the healthy cochlea. From the available data it is not possible to infer whether the sample size has influenced the obtained results and the study should be repeated with a larger sample size and assessing more frequencies.

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Related in: MedlinePlus

DPOAE I/O functions at 2 and 4 kHz with and without contralateral acoustic stimulation and considering all tested stimulus intensities (35 to 75 dB peSPL). The y-axis depicts stimulus intensity and the x-axis DPOAE amplitude. The growth/pattern of the curves is not significantly modified, after CAS at 2 or at 4 kHz.
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f1-medscimonit-17-10-cr557: DPOAE I/O functions at 2 and 4 kHz with and without contralateral acoustic stimulation and considering all tested stimulus intensities (35 to 75 dB peSPL). The y-axis depicts stimulus intensity and the x-axis DPOAE amplitude. The growth/pattern of the curves is not significantly modified, after CAS at 2 or at 4 kHz.

Mentions: In the second set, the slope of the DPOAE I/O function presented means of 2.99 and 2.36 at 2 kHz and 3.63 and 2.46 at 4 kHz, without and with CAS, respectively. The suppression effect on the DPOAE slopes was higher than in the first group, but the estimated differences were not statistically significant (p=0.16 and 0.28). Figure 1 summarizes these findings.


Contralateral suppression of otoacoustic emissions: input-output functions in neonates.

Campos Ude P, Hatzopoulos S, Kochanek K, Sliwa L, Skarzynski H, Carvallo RM - Med. Sci. Monit. (2011)

DPOAE I/O functions at 2 and 4 kHz with and without contralateral acoustic stimulation and considering all tested stimulus intensities (35 to 75 dB peSPL). The y-axis depicts stimulus intensity and the x-axis DPOAE amplitude. The growth/pattern of the curves is not significantly modified, after CAS at 2 or at 4 kHz.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3539483&req=5

f1-medscimonit-17-10-cr557: DPOAE I/O functions at 2 and 4 kHz with and without contralateral acoustic stimulation and considering all tested stimulus intensities (35 to 75 dB peSPL). The y-axis depicts stimulus intensity and the x-axis DPOAE amplitude. The growth/pattern of the curves is not significantly modified, after CAS at 2 or at 4 kHz.
Mentions: In the second set, the slope of the DPOAE I/O function presented means of 2.99 and 2.36 at 2 kHz and 3.63 and 2.46 at 4 kHz, without and with CAS, respectively. The suppression effect on the DPOAE slopes was higher than in the first group, but the estimated differences were not statistically significant (p=0.16 and 0.28). Figure 1 summarizes these findings.

Bottom Line: Significant DPOAE amplitude suppression effects were observed at various L2 stimulus levels for both tested frequencies at 2 and 4 kHz.In contrast, the corresponding DPOAE slopes showed various alterations that were not statistically significant.From the available data it is not possible to infer whether the sample size has influenced the obtained results and the study should be repeated with a larger sample size and assessing more frequencies.

View Article: PubMed Central - PubMed

Affiliation: University of São Paulo, São Paulo, Brazil.

ABSTRACT

Background: The literature suggests that contralateral acoustic stimulation (CAS) alters the amplitude of the distortion product otoacoustic emissions (DPOAEs), but it is still unknown whether the DPOAE Input/Output (I/O) functions are also affected. To elucidate this aspect of the DPOAEs, the present study assessed the effects of CAS on DPOAE I/O functions at the frequencies of 2 kHz and 4 kHz, in a sample of term neonatal subjects.

Material/methods: Sixty randomly selected neonates were included in the study. The DPOAE I/O functions were obtained at 2 kHz and 4 kHz, in the presence of a 60 dB SPL broad band-contralateral white noise, using the TDH39 headphones contralaterally. DPOAEs were recorded up to a stimulus level of L2 = 35 dB peSPL.

Results: Significant DPOAE amplitude suppression effects were observed at various L2 stimulus levels for both tested frequencies at 2 and 4 kHz. In contrast, the corresponding DPOAE slopes showed various alterations that were not statistically significant.

Conclusions: The data from the present study show that contralateral acoustic stimulation significantly affects only the amplitude of the DPOAE I/O functions; the slope is affected, but not significantly. This observation can shed light on the nature of CAS, suggesting that the latter is primarily a linear phenomenon without the cochlear compression and non-linear components seen in the healthy cochlea. From the available data it is not possible to infer whether the sample size has influenced the obtained results and the study should be repeated with a larger sample size and assessing more frequencies.

Show MeSH
Related in: MedlinePlus