Growth of suppression using distortion-product otoacoustic emission measurements in hearing-impaired humans

Abstract

Growth of distortion-product otoacoustic emission suppression was measured in 65 subjects with mild-to-moderate sensorineural hearing loss (HI). Measurements were made at four probe frequencies (f 2 ) and up to five L 2 levels. Eleven suppressor frequencies (f 3 ) were used for each f 2 , L 2 combination. These data were compared to data from normal-hearing (NH) subjects (Gorga et al., 2011a). In both NH and HI subjects, growth of suppression depended on the relation between f 2 and f 3 , such that the slope was close to one when f 3 % f 2 , steeper than one when f 3 < f 2 , and shallower than one when f 3 > f 2 . Differences in growth of suppression between NH and HI subjects were not observed for fixed f 2 , L 2 combinations, however large differences were observed in suppressor "threshold" when compared at the same probe sensation level (dB SL). Smaller group differences were observed when compared at the same probe sound-pressure level (dB SPL). Therefore, the extent of these differences depended on how probe level (L 2 ) was specified. When the results from NH and HI subjects are compared with each other and with psychophysical studies of masking, differences are observed that have implications for the remediation of mild-to-moderate hearing loss.

Multi-tone suppression of distortion-product otoacoustic emissions in humans

“…Specifically, suppression threshold and growth depend on the relation between probe frequency and level (f 2 and L 2 ) and suppressor frequency (f s ). Previous studies have described details of DPOAE suppression characteristics for single suppressors for both normal-hearing (Abdala, 2001;Abdala and Chatterjee, 2003;Gorga et al, 2011a,b) and hearingimpaired subjects (Abdala and Fitzgerald, 2003;Gorga et al, 2003;Birkholz et al, 2012;Gruhlke et al, 2012). In the present study, the fact that the MLR accounted for 94% of the variance across all participants in the singlesuppressor decrement functions validates the transformation described by Eq.…”

“…Although DPOAE generation mechanisms may be more complex theoretically compared to SFOAEs, DPOAEs were favored for this study because (1) we have experience measuring DPOAE suppression in previous studies (e.g., Gorga et al, 2008;Gorga et al, 2011a,b;Gruhlke et al, 2012;Birkholz et al, 2012) and (2) the study was motivated by a recent paper by Rasetshwane et al (2014) describing a signal-processing algorithm inspired by DPOAE suppression data that assumes an additive-intensity model.…”

“…Rasetshwane et al (2014) used data from Gorga et al (2008) and Gorga et al (2011b) to develop a signalprocessing algorithm for hearing aids that aims to restore, among other things, normal suppression, which presumably would be beneficial to individuals with hearing loss because they lack normal cochlear suppression (Abdala and Fitzgerald, 2003;Gorga et al, 2003;Birkholz et al, 2012;Gruhlke et al, 2012). In order to generalize the suppressive effect of a single suppressor tone to the case when there are multiple frequency components, Rasetshwane et al (2014) assumed that suppressive effects were additive in terms of variables that represented the relative intensities of different frequency components.…”

Distortion-product otoacoustic emission suppression tuning curves in hearing-impaired humans

“…The data used in this study to construct STCs are the same data that were used to describe growth of suppression in ears with hearing loss (Birkholz et al, 2012). HI subjects were categorized according to behavioral threshold into three groups: 20-25, 30-35, and 40-45 dB HL.…”

“…Distortion-product otoacoustic emissions (DPOAE) were used to describe growth of suppression as a function of suppressor level for a wide range of suppressor frequencies in subjects with mild-to-moderate hearing loss (Birkholz et al, 2012). The present study describes DPOAE suppression tuning curves (STCs) in the same group of subjects, constructed from the growth-of-suppression data.…”