Exploring Optimal Stimulus Frequency Ratio for Measurement of the Quadratic f 2 –f 1 Distortion Product Otoacoustic Emission in Humans

2018 ◽  
Vol 61 (7) ◽  
pp. 1794-1806
Author(s):  
Rachael R. Baiduc ◽  
Sumitrajit Dhar
Keyword(s):  
Otoacoustic Emissions ◽  
Endolymphatic Hydrops ◽  
Stimulus Frequency ◽  
Otoacoustic Emission ◽  
Normal Hearing ◽  
Distortion Product Otoacoustic Emission ◽  
Clinical Implementation ◽  
Distortion Product ◽  
Recent Interest ◽  
Stimulus Parameters

Purpose Distortion product otoacoustic emissions (DPOAEs) are a by-product of active cochlear processes that lead to the compressive nonlinearity of healthy ears. The most commonly studied emission is at the frequency 2f 1 –f 2 , but there has been recent interest in using the quadratic distortion product at the frequency f 2 –f 1 to detect cochleopathies including endolymphatic hydrops. Before the DPOAE at f 2 –f 1 can be applied clinically in any capacity, optimal stimulus parameters for its elicitation must be established. Method We investigated stimulus parameters for the DPOAEs at f 2 –f 1 and 2f 1 –f 2 in 23 adults with normal hearing. Logarithmically swept tones between approximately 0.6 and 20 kHz (L 1 = L 2 = 70 dB SPL) served as the higher frequency stimulus (f 2 ). DPOAEs were measured for 6 f 2 /f 1 ratios: 1.14, 1.18, 1.22, 1.30, 1.32, and 1.36. Results Both DPOAEs were consistently measurable. In line with previous investigations, the highest levels of the DPOAE at 2f 1 –f 2 were generated between f 2 /f 1 ratios of 1.14–1.22, with a peak in the level ratio function at 1.22. In contrast, f 2 –f 1 was less influenced by ratio, although the narrowest ratio (1.14) produced slightly higher levels across frequency. Conclusion The DPOAE at f 2 –f 1 is measurable in individuals with normal hearing up to f 2 of 20 kHz at narrow f 2 /f 1 ratios. Measurements at additional stimulus levels and in subjects with hearing impairment will be needed before clinical implementation.

Cochlear Sources and Otoacoustic Emissions

2010 ◽  
Vol 21 (03) ◽  
pp. 176-186 ◽  
Author(s):  
Tiffany A. Johnson
Keyword(s):  
Fine Structure ◽  
Otoacoustic Emissions ◽  
Stimulus Frequency ◽  
Normal Hearing ◽  
Clinical Applications ◽  
Clinical Test ◽  
Similar Amount ◽  
Distortion Product ◽  
Stimulus Parameters ◽  
Coherent Reflection

Current understanding suggests that there are two different mechanisms by which otoacoustic emissions (OAEs) are generated in the cochlea. These mechanisms include a nonlinear-distortion mechanism and a coherent-reflection mechanism. Distortion product OAEs (DPOAEs) are believed to include contributions from both mechanisms, while stimulus frequency OAEs (SFOAES), at least at low and moderate levels, are believed to be generated primarily by the coherent-reflection mechanism. In the case of DPOAEs, the interaction of the two mechanisms produces a series of alternating peaks and valleys in the response level when recorded in small frequency increments. This pattern of peaks and valleys typically is referred to as fine structure. There has been much speculation that the interaction of the two mechanisms and the resulting fine structure limits the clinical test performance of DPOAEs. There are few data to address this speculation. Here, we review the literature that describes the cochlear source mechanisms and their potential relationship to clinical applications. We then present results for preliminary data collected in a group of 10 normal-hearing subjects where we explore the influence of common approaches to setting DPOAE stimulus parameters on the resulting fine structure. These preliminary results suggest that, at the moderate stimulus levels used in clinical applications, each of the different stimulus parameters results in a similar amount of fine structure and, therefore, fine structure cannot be eliminated through manipulation of stimulus parameters. We also review the results of some preliminary efforts to identify stimulus parameters that can be used to record SFOAEs (OAEs generated by the reflection mechanism). The potential clinical applications of SFOAEs have received little attention in the literature. By identifying stimulus parameters producing robust responses in normal-hearing ears, it may be possible to more fully evaluate clinical applications of SFOAEs.

Distortion product otoacoustic emissions following stapedectomy versus stapedotomy

2009 ◽  
Vol 124 (1) ◽  
pp. 16-18
Author(s):  
L Migirov ◽  
M Wolf
Keyword(s):  
Otoacoustic Emissions ◽  
Surgical Techniques ◽  
Otoacoustic Emission ◽  
Normal Hearing ◽  
Stapes Surgery ◽  
Distortion Product Otoacoustic Emissions ◽  
Control Group ◽  
Distortion Product Otoacoustic Emission ◽  
Distortion Product ◽  
Gap Closure

AbstractObjectives:To evaluate distortion product otoacoustic emissions following stapes surgery in patients with otosclerosis, and to compare in this respect two surgical techniques used in our department.Method:This retrospective study included 17 stapedectomy and 23 stapedotomy patients aged 16–68 years who had been followed up for at least 12 months. Distortion product otoacoustic emission results at 2, 3, 4 and 5 kHz (i.e. =f2, with 2f1 − f2 = 0.6f2) were obtained pre-operatively and four weeks post-operatively. The control group included 13 volunteers aged 18–50 years with normal hearing and normal otoscopic findings.Results:Distortion product otoacoustic emissions were detected pre-operatively in 34.8 per cent of stapedotomy patients and 29.4 per cent of stapedectomy patients, and post-operatively in 91.3 per cent of stapedotomy patients and 88.2 per cent of stapedectomy patients. The differences between the stapedotomy and stapedectomy groups were statistically insignificant for each tested frequency, both pre- and post-operatively. The patients' post-operative distortion product otoacoustic emission amplitudes were less than those of normal hearing individuals, even in patients with complete air–bone gap closure and a significant improvement in hearing.Conclusion:Distortion product otoacoustic emissions were detected in most of our patients following successful stapes surgery, and appeared to be unaffected by the surgical technique or prosthesis used.

Clinical characteristics and audiological significance of spontaneous otoacoustic emissions in tinnitus patients with normal hearing

2010 ◽  
Vol 125 (3) ◽  
pp. 246-250 ◽  
Author(s):  
D-K Kim ◽  
S-N Park ◽  
K-H Park ◽  
H G Choi ◽  
E-J Jeon ◽  
...  
Keyword(s):  
Otoacoustic Emissions ◽  
Early Stage ◽  
Otoacoustic Emission ◽  
Normal Hearing ◽  
Control Group ◽  
Study Group ◽  
Distortion Product Otoacoustic Emission ◽  
Spontaneous Otoacoustic Emissions ◽  
Distortion Product ◽  
The Mean

AbstractObjective:To define the clinical and audiological features of normal-hearing tinnitus patients with spontaneous otoacoustic emissions, and to evaluate the role of spontaneous otoacoustic emissions in tinnitus generation.Materials and methods:Thirty-two patients with spontaneous otoacoustic emissions were compared with 29 patients without spontaneous otoacoustic emissions, regarding clinical and audiological aspects.Results:The mean age of the study group subjects was significantly lower, and they experienced the kindling effect less frequently than the control group. The mean tinnitus handicap inventory score of the study group was considerably higher than that of the controls, although the difference was not statistically significant. The study group had significantly quieter tinnitus, and higher transient evoked and distortion product otoacoustic emission responses, compared with the control group.Conclusions:Normal-hearing tinnitus patients with spontaneous otoacoustic emissions have different clinical and audiological characteristics, compared with those without spontaneous otoacoustic emissions. Appropriate evaluation and treatment should be considered at an early stage in these patients.

Effect of mastoid drilling on hearing of the contralateral ear

2013 ◽  
Vol 127 (10) ◽  
pp. 952-956 ◽  
Author(s):  
A Goyal ◽  
P P Singh ◽  
A Vashishth
Keyword(s):  
Hearing Loss ◽  
High Frequency ◽  
Otoacoustic Emissions ◽  
Pure Tone Audiometry ◽  
Otoacoustic Emission ◽  
Prospective Clinical Study ◽  
Distortion Product Otoacoustic Emission ◽  
High Frequencies ◽  
Distortion Product ◽  
Contralateral Ear

AbstractObjectives:This study aimed to: understand the effect that high intensity noise associated with drilling (during otological surgery) has on hearing in the contralateral ear; determine the nature of hearing loss, if any, by establishing whether it is temporary or persistent; and examine the association between hearing loss and various drill parameters.Methods:A prospective clinical study was carried out at a tertiary centre. Thirty patients with unilateral cholesteatoma and normal contralateral hearing were included. Patients were evaluated pre-operatively and for five days following surgery using high frequency pure tone audiometry, and low and high frequency transient evoked and distortion product otoacoustic emission testing.Results:The findings revealed statistically significant changes in distortion product otoacoustic emissions at high frequencies (p = 0.016), and in transient evoked otoacoustic emissions at both low and high frequencies (p = 0.035 and 0.021, respectively). There was a higher statistical association between otoacoustic emission changes and cutting burrs compared with diamond burrs.Conclusion:Drilling during mastoid surgery poses a threat to hearing in the contralateral ear due to noise and vibration conducted transcranially.

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