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. 2006 Jan;119(1):418-28.
doi: 10.1121/1.2133714.

Influence of primary-level and primary-frequency ratios on human distortion product otoacoustic emissions

Tiffany A Johnson  1 , Stephen T Neely, Cassie A Garner, Michael P Gorga
Affiliations

Influence of primary-level and primary-frequency ratios on human distortion product otoacoustic emissions

Tiffany A Johnson et al. J Acoust Soc Am. 2006 Jan.

Abstract

The combined influence of primary-level differences (L1-L2) and primary-frequency ratio (f2/f1) on distortion product otoacoustic emission (DPOAE) level was investigated in 20 normal-hearing subjects. DPOAEs were recorded with continuously varying stimulus levels [Neely et al. J. Acoust. Soc. Am. 117, 1248-1259 (2005)] for the following stimulus conditions: f2= 1, 2, 4, and 8 kHz and f2/f1=1.05 to 1.4; various L1-L2, including one individually optimized to produce the largest DPOAE. For broadly spaced primary frequencies at low L2 levels, the largest DPOAEs were recorded when L1 was much higher than L2, with L1 remaining relatively constant as L2 increased. As f2/fl decreased, the largest DPOAEs were observed when L1 was closer to L2 and increased as L2 increased. Optimal values for L1-L2 and f2 f1 were derived from these data. In general, average DPOAE levels for the new L1-L2 and f2/f1 were equivalent to or larger than those observed for other stimulus combinations, including the L1-L2 described by Kummer et al. [J. Acoust. Soc. Am. 103, 3431-3444 (1998)] and those defined by Neely et al. in which L1-L2 was evaluated, but f2/f1 was fixed at 1.2.

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Figures

Figure 1
Figure 1
Contour plots representing DPOAE level in L1, L2 stimulus space. Each column represents data for a different f2 and each row represents a different f2/f1, as indicated on the figure. The contours are spaced in 2-dB increments of DPOAE level. As a reference, the contour corresponding to -6 dB SPL is indicated with a thicker line. The maximum DPOAE level in panels without a reference (f2 = 8 kHz, f2/f1 = 1.40, 1.35, 1.05) is -8 dB SPL. The slanting, straight lines in each panel describe the L1, L2 relationship producing the largest DPOAE level at each L2. Our approach for fitting this line is described in the text.
Figure 2
Figure 2
The slope of the average, optimal path as a function of f2/f1. The parameter is f2.
Figure 3
Figure 3
DPOAE level (Ldp) is plotted as a function of L2 with primary-frequency ratio as a parameter. Each panel represents a different f2, as indicated. The solid line in each panel represents DPOAE level for f2/f1 = 1.20. Shorter dashes correspond to f2/f1 > 1.20 and longer dashes correspond to f2/f1 < 1.20. The line thickness represents the distance the frequency ratio is from 1.20, with f2/f1 = 1.05 and 1.40 indicated by the thinnest dashed lines.
Figure 4
Figure 4
Mean DPOAE level (Ldp) as a function of frequency ratio. Each panel represents data for a different f2. Here, the parameter is L2, with decreasing line thickness indicating increasing L2 in 10-dB increments of L2. When f2 = 8 kHz, data for L2 = 30 to 80 dB SPL are plotted, for all other f2 frequencies data are plotted for L2 ranging from 20 to 80 dB SPL.
Figure 5
Figure 5
Mean DPOAE level (Ldp) as a function of frequency ratio when f2 = 4 kHz and L2 = 20, 50, and 80 dB SPL (indicated with decreasing line thickness). Errors bars represent ± 1 standard deviation.
Figure 6
Figure 6
Our approach to specifying optimal stimulus parameters. The upper panel plots L1 as a function of L2 while the lower panel plots f2/f1 as a function of L2. The parameter is f2, as indicated within the upper panel. The symbols shown in each panel correspond to the L1 (upper panel) or f2/f1 (lower panel) producing the largest DPOAE at each L2. The lines in each panel represent the best fit to the stimulus conditions producing the maximum DPOAE according to the approach described in the text. The equations describing these lines are shown as an inset in each panel.
Figure 7
Figure 7
DPOAE level (Ldp) as a function of L2. Each panel represents a different f2. The parameter is the stimulus condition used to record the DPOAE, as indicated in the legend. The nearly horizontal lines near the bottom of each panel represent the corresponding noise levels.
Figure 8
Figure 8
DPOAE noise levels (Ln) as a function of frequency ratio with each panel corresponding to a different f2. Each symbol corresponds to a different L1, L2 path as indicated in the legend.
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References

    1. Abdala C. Distortion product otoacoustic emission (2f1-f2) amplitude growth in human adults and neonates. J. Acoust. Soc. Am. 2000;107:446–456. - PubMed
    1. Abdala C. A longitudinal study of distortion product otoacoustic emission ipsilateral suppression and input/output characteristics in human neonates. J. Acoust. Soc. Am. 2003;114:3239–3250. - PubMed
    1. Abdala C, Fitzgerald TS. Ipsilateral distortion product otoacoustic emission (2f1-f2) suppression in children with sensorineural hearing loss. J. Acoust. Soc. Am. 2003;114:919–31. - PubMed
    1. ANSI . Specifications for audiometers. American National Standards Institute; New York: 1996. ANSI 3.6-1996.
    1. Brown AM, Gaskill SA. Measurement of acoustic distortion reveals underlying similarities between human and rodent mechanical responses. J. Acoust. Soc. Am. 1990;88:840–849. - PubMed

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