Utility of Standard DPOAEs in the Evaluation of the Normal-Hearing Tinnitus Patient

Utility of Standard DPOAEs in the Evaluation of the Normal-Hearing Tinnitus Patient

Background Shiomi et al, 1997 (Journal of the Association of Research In Otology): In comparison to normal-hearing and otologically normal subjects (including no tinnitus), DPOAE amplitudes were consistently reduced among tinnitus patients, even in those with audiometrically normal hearing. Hall, 2 (Handbook of Otoacoustic Emissions):... a clear pattern has emerged. OAEs are abnormal, or not detectable, in the frequency region of the tinnitus, even among persons with clinically normal audiograms. Onishi et al, 24 (International Tinnitus Journal): The authors conclude that DPOAEs constitute a useful audiological method for evaluation of patients complaining of tinnitus. [61.3% of normal-hearing tinnitus subjects demonstrated DPOAE amplitudes below the 5 th percentile compared to only 3.6% in the control group.]

Background Granjeiro et al, 28 (Otolaryngology - Head and Neck Surgery):... DPOAE were abnormal in 68.4% of [tinnitus subjects] and in 5 of [non-tinnitus subjects]. Paglialonga et al, 21 (Auris Nasus Larynx):... abnormal OAEs, in particular at higher frequencies, [was observed] in tinnitus subjects with normal hearing sensitivity... outer hair cell dysfunction... might thus be assumed in normal-hearing tinnitus subjects. Jastrebof & Hazell, 24 (Tinnitus Retraining Therapy: Implementing the Neurophysiological Model): Approximately 2 of patients with tinnitus have normal hearing. This is because changes too small to be detectable on a standard audiogram, if localized, can result in heterogeneity and trigger compensatory reactions of the auditory system, resulting in tinnitus.

Research Question & Data Collection We were interested in evaluating the clinical utility of standard DPOAE measures during routine audiological evaluation of tinnitus patients with normal hearing through the standard audiometric test range of.25-8 khz, so we asked: o Can standard DPOAE measures differentiate between normal-hearing tinnitus patients and normal-hearing non-tinnitus patients? Data Collection o VA Computerized Patient Record System (CPRS) was reviewed for patients referred for primary complaint of tinnitus between 1 Jan 211-31 Dec 211 (12 months). o o All subjects had normal hearing thresholds (< 25 db HL) at all frequencies.25-8 khz. All subjects DPOAEs were measured using a standard clinical Bio Logic Scout DPOAE protocol.

Subject Characteristics Subjects identified: 28 (56 ears) Female subjects excluded (n = 2) Monaural tinnitus subjects excluded (n = 1) Final n = 25 (5 ears) Mean Age: 42.1 years (SD = 9.28) < 3 = 6 (24 %) 4 31-4 = 4 (16 %) 41-5 = 9 (36 %) 6 > 51 = 6 (24 %) Gender Male = 25 (1 %) Tinnitus Description Ring Only = 18 (72 %) Other Only = 1 ( 4 %) Ring + Other = 6 (24 %) SC for Tinnitus Yes = 1 (36 %) No = 15 (64 %) Tinnitus Ear Both Ears = 25 (1 %) Tinnitus Awareness 1 of the time = 15 (6 %) 71-99% of the time = 7 (28%) 51-7 of the time = 2 ( 8%) 36-5 of the time = 1 ( 4%) Mental Health Disorders Yes = 17 (68%) 1 MH Diagnosis = 11 (65%) 2+ MH Diagnoses = 6 (35 %) No = 8 (32%)

Audiological Findings -1 1 2 3 4 Acoustic Reflexes at 1 khz Right Contra Right Ipsi Left Contra Left Ipsi Mean 83.41 8.68 84.9 81.82 S.D. 7.3 5.83 5.49 5.68 5 6 7 8 Speech Audiometry Right Ear Left Ear 9 1 11.25k.5k 1k 2k 3k 4k 6k 8k SRT WRS % db HL SRT WRS % db HL Mean 9.63 94.5 53.88 9.17 94. 54.17 S.D. 4.12 6.86 5.63 4.52 9.21 5.65

DPOAE Pass-Fail Criteria Most absolute DPOAE interpretation criteria have been published for hearing screening purposes rather than for determination of normal OHC status. Most judgments of abnormal DPOAE in normal hearing tinnitus patients have been based on comparison to normal-hearing non-tinnitus patients rather than absolute values However, there are exceptions as denoted by * below. SNR > 13 db Zapala et al (27) SNR > 6 db Wagner et al (28) Granjeiro et al (27)* Iowa State Newborn Screening Protocol Gorga et al (25)* 5 th Percentile Onishi Et al (24)* SNR > 3 db Washington State Newborn Screening Protocol SNR > 3-6 db above 2 SD above the noise floor Gorga et al (2)* Christensen (27) Various DPOAE screeners SNR > 5 SNR > 6 SNR > 1 Hall & Muller (1997) Response replicability within + 3-5 db

Bio-Logic Scout Available Protocols and Norms

Selected Bio-Logic Scout DPOAE Protocol Frequency range: 75-8 Hz (8 data points) f2 / f1 Ratio = 1.22 DP = 2(f1) - (f2) zzzzzzzz L1 = 65 db L2 = 55 db Sample Size = 124 (each, 2 runs)

The Vanderbilt Data Set vs. Current Protocol About the Vanderbilt Data Set 15 male and 15 female subjects No gender differences observed for DPOAE amplitudes Ages ranged from 21-28 years Data were collected in quiet (not sound-treated) room All thresholds 5-8 Hz for both ears < 15 db HL Vanderbilt f2 (Hz) Current Protocol f2 (Hz) Difference (Hz) % Octave Difference Equivalent Pts/Octave Vandy Mean Amplitude (db SPL) Vandy SD Vandy Mean minus 2 SD Vandy Mean minus 1 SD Vandy 5 th %ile 634 -- -- -- -- 9.25 5.97-2.69 3.28 7.34 85 75 + 55 7.33 % 14 9.5 6.39-3.77 2.62 6.96 11 131-3 3. % 3 1.18 6.56-2.94 3.62 8.9 1586 1453 + 133 9.15 % 11 1.65 6.63-2.61 4.2 8.53 22 216-14.7 % 1428 6.85 6.4-5.95.45 4.81 3174 2859 + 315 11.2 % 9 6.1 5.18-4.26.92 4.44 43 3984 + 19.5 % 2 6.1 5.68-5.26.42 4.28 6347 5672 + 575 1.1 % 1 1.22 8.51-15.8-7.29-1.5 -- 816 -- -- -- -- -- -- -- --

Signal-to-Noise Ratios (SNRs) 3 3 25 25 2 2 15 15 1 1 Right Ear 5 Left Ear 5 75 131 1453 216 2859 3984 5672 816 75 131 1453 216 2859 3984 5672 816 Mean DPOAE SNRs for the right and left ears of 25 subjects. No significant differences were found between the two runs or between both ears at any frequency (p >.5). Gray lines are the 25 th and 75 th percentiles. Two separate runs are shown.

Signal-to-Noise Ratios (SNRs) 3 25 2 15 1 5 75 131 1453 216 2859 3984 5672 816 Mean DPOAE SNRs for the right and left ears of 25 subjects. No significant differences were found between the two runs or between both ears at any frequency (p >.5). Gray lines are the 25 th and 75 th percentiles. Two separate runs are shown.

Signal-to-Noise Ratios (SNRs) 3 25 2 15 1 5 75 131 1453 216 2859 3984 5672 816 Mean DPOAE SNRs for the right and left ears for two combined runs of 25 subjects. No significant differences were found between the two runs or between both ears at any frequency (p >.5). Gray lines are the 25 th and 75 th percentiles.

Signal-to-Noise Ratios (SNRs) 3 25 2 15 1 5 75 131 1453 216 2859 3984 5672 816 Mean DPOAE SNRs for the right and left ears for two combined runs of 22 subjects. No significant differences were found between the two runs or between both ears at any frequency (p >.5). Gray lines are the 25 th and 75 th percentiles. SNR criteria are shown.

Criterion: DP Amplitude -1 SD from mean DPOAE amplitude is lower than 64.2% of normals -2 SD from mean: DPOAE amplitude is lower than 95.6% of normals 5 th Percentile: DPOAE amplitude is lower than 95% of normals

DP Amplitudes / Noise Floors 2 2 15 15 1 1 5 5-5 -5-1 -1-15 -15-2 -2 Right Ear 75 131 1453 216 2859 3984 5672 816 f 2 Hz -25-3 Left Ear 75 131 1453 216 2859 3984 5672 816 f 2 Hz -25-3 Mean DPOAE amplitudes and noise floors for the right and left ears of 22 subjects. No significant differences were found between the two runs or between both ears at any frequency (p >.5). Gray lines are the 25 th and 75 th percentiles. Two separate runs are shown.

DP Amplitudes / Noise Floors 2 15 1 5-5 -1-15 -2-25 75 131 1453 216 2859 3984 5672 816 f 2 Hz -3 Mean DPOAE amplitudes and noise floors for the right and left ears of 25 subjects. No significant differences were found between the two runs or between both ears at any frequency (p >.5). Gray lines are the 25 th and 75 th percentiles. Two separate runs are shown.

DP Amplitudes: Both Ears, Two Runs 2 15 1 5-5 -1-15 -2-25 75 131 1453 216 2859 3984 5672 816 f 2 Hz -3 Mean DPOAE amplitudes for the combined right and left ears for two combined runs of 25 subjects. No significant differences were found between the two runs or between both ears at any frequency (p >.5). Gray lines are the 25 th and 75 th percentiles.

Amplitude Criteria Comparison 2 15 1 5-5 -1-15 -2-25 75 131 1453 216 2859 3984 5672 816 f 2 Hz -3 Mean DPOAE amplitudes for the combined right and left ears for two combined runs of 25 subjects. No significant differences were found between the two runs or between both ears at any frequency (p >.5). Gray lines are the 25 th and 75 th percentiles. Amplitude criteria also are shown.

Amplitude Criteria Comparison 2 15 6 > (2SD > NF) 1 5-5 -1-15 -2-25 75 131 1453 216 2859 3984 5672 816 f 2 Hz -3 Mean DPOAE amplitudes for the combined right and left ears for two combined runs of 25 subjects. No significant differences were found between the two runs or between both ears at any frequency (p >.5). Gray lines are the 25 th and 75 th percentiles. Amplitude criteria also are shown.

Amplitude Criteria Comparison 2 15 1 5-5 -1-15 -2-25 75 131 1453 216 2859 3984 5672 816 f 2 Hz -3 Mean DPOAE amplitudes for the combined right and left ears for two combined runs of 25 subjects. No significant differences were found between the two runs or between both ears at any frequency (p >.5). Gray lines are the 25 th and 75 th percentiles. Amplitude criteria also are shown.

Amplitude Criteria Comparison 2 15 1 5-5 -1-15 -2-25 75 131 1453 216 2859 3984 5672 816 f 2 Hz -3 Mean DPOAE amplitudes for the combined right and left ears for two combined runs of 25 subjects. No significant differences were found between the two runs or between both ears at any frequency (p >.5). Gray lines are the 25 th and 75 th percentiles. Amplitude criteria also are shown.

Response Abnormality: Results per Criterion Signal-to-Noise Ratio (SNR) Criteria > 3 db > 6 db > 6 db above 2 SD above the noise floor Amplitude Criteria > -1 SD > -2 SD > Vandy 5 th Percentile Replicability Criterion + 3 db High-Frequency Responses Criterion 2, 3 and 4 out of 4 abnormal responses 2 and 3 out of 3 abnormal responses

% Abnormal DPOAES per Criterion: 3 db SNR 6% All Subjects per Frequency Right Right Left Left Both Both 24% 12% 16% 18% 19% 14% 6% 8% 14% 5% 4% 7% 6% 1% 2% 75 131 1453 216 2859 3984 5672 816 1 9 8 7 6 5 4 3 2 1 1 9 8 7 6 5 4 3 2 1 All Frequencies per Subject 18% 14% 12% 14% 6% 8% 8% 2% 2% 2% 4% 2% 4% 6% 2% 2% 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 19 2 21 22 23 24 25

% Abnormal DPOAES per Criterion: 6 db SNR 9% All Subjects per Frequency 14% 4% 4% 4% 4% 75 131 3% 2% 4% 1453 Right Right Left Left Both Both 22% 16% 1 6% 8% 4% 216 2859 3984 23% 26% 2 5672 36% 29% 22% 816 1 9 8 7 6 5 4 3 2 1 1 9 8 7 6 5 4 3 2 1 All Frequencies per Subject 36% 2 16% 18% 2 6% 6% 4% 4% 4% 6% 8% 2% 4% 6% 2% 4% 6% 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 19 2 21 22 23 24 25

% Abnormal DPOAEs: Amplitude Vanderbilt -2 SD 6% All Subjects per Frequency Right Left Both 12% 18% 18% 16% 12% 15% 17% 12% 14% 14% 8% 1 8% 14% 4% 4% 4% 7% 6% 75 131 1453 216 2859 3984 5672 816 1 9 8 7 6 5 4 3 2 1 1 9 8 7 6 5 4 3 2 1 All Frequencies per Subject 71% 64% 43% 21% 18% 11% 11% 7% 7% 4% 4% 4% 4% 4% 4% 4% 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 19 2 21 22 23 24 25

% Abnormal DPOAEs: Amplitude Vanderbilt -1 SD All Subjects per Frequency Right Left Both 1 9 8 7 6 28% 3 26% 19% 18% 2 24% 24% 24% 18% 18% 18% 36% 36% 36% 38% 31% 24% 4 4 4 5 4 3 2 1 75 131 1453 216 2859 3984 5672 816 1 9 8 7 6 5 4 3 2 1 96% 1 All Frequencies per Subject 61% 61% 54% 39% 39% 32% 29% 29% 25% 21% 14% 14% 14% 11% 11% 7% 7% 7% 7% 7% 4% 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 19 2 21 22 23 24 25

% Abnormal DPOAEs: Amplitude Vanderbilt 5 th %ile All Subjects per Frequency Right Left Both 66% 68% 62% 64% 6 61% 61% 56% 54% 54% 47% 5 44% 47% 4 36% 36% 36% 37% 38% 36% 75 131 1453 216 2859 3984 5672 816 1 9 8 7 6 5 4 3 2 1 1 9 8 7 6 5 4 3 2 1 1 1 89% 86% All Frequencies per Subject 89% 75% 75% 68% 64% 64% 57% 54% 43% 43% 36% 36% 29% 29% 29% 25% 21% 21% 21% 21% 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 19 2 21 22 23 24 25

Amplitude Criterion: 6 db above the NF + 2 SD 92% 86% 8 75 59% 62% 56% 131 26% 26% 26% 1453 Right Left Both Right Left Both 43% 42% 44% 4 42% 38% 36% 37% 32% 216 2859 3984 72% 66% 6 5672 67% 66% 68% 816 1 9 8 7 6 5 4 3 2 1 1 9 8 7 6 5 4 3 2 1 1 97% 84% 84% All Frequencies per Subject 84% 78% 78% 72% 56% 5 5 53% 53% 47% 44% 47% 38% 31% 31% 25% 19% 22% 9% 38% 34% 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 19 2 21 22 23 24 25

Amplitude Criterion: Replicability 7 1 Avg R Avg L 6 5 4 3 2 1-1 -2-3 2 Percentage of Responses with Replicability Poorer than + 3 db 16% 7% 7% 9% 7% 16% 36% 9 8 7 6 5 4 3 2 1 75 131 1453 216 2859 3984 5672 816-4 75 131 1453 216 2859 3984 5672 816 Average amplitude difference (db) for two runs Two runs for both ears combined Amplitude replicability should be within + 3-5 db (Hall & Muller, 1997). We chose + 3 db as the more stringent criterion.

Criterion Comparison: % Abnormal Responses 1SD 2SD <3 SNR <6 SNR 5th %ile 6>(2SD>NF) Repl (>3 db) 1 9 8 1 9 8 7 6 5 4 7 6 5 4 3 35.8% 5.3% 51.8% 3 2 2 1 6.8% 9.2% 11.5% 17. 1 75 131 1453 216 2859 3984 5672 816 Percentage of all responses that were abnormal at each test frequency per criterion (2 ears, 2 runs combined) Percentage of all responses that were abnormal for all test frequencies combined per criterion (2 ears, 2 runs combined). * < 1% of all responses for all test frequencies combined were < 3 db above 2SD above the noise floor

Criterion Comparison: % Abnormal Responses 1 1 5th %ile 6>(2SD>NF) 9 9 8 8 7 7 6 5 4 3 2 1 6 5 4 3 2 1 5.3% 51.8% 75 131 1453 216 2859 3984 5672 816 5th %ile 6>(2SD>NF) Percentage of all responses that were abnormal at each test frequency per criterion (2 ears, 2 runs combined) Percentage of all responses that were abnormal for all test frequencies combined per criterion (2 ears, 2 runs combined).

Criterion: % Abnormal High-Frequency DPOAEs 1 9 8 7 6 5 4 3 2 1 18% Right Left Both 22% 2 4 44% 42% 66% 6 4/4 3/4 2/4 3/3 2/3 63% --------------------------- 6dB > (2SD > NF) ------------------------- 816, 5672, 3984 and 2859 Hz 32% 4 36% 48% 54% 51% --------------- Vandy 5 th % --------------- 5672, 3984 and 2859 Hz Criterion: Abnormal high-frequency DPOAEs 6dB >(2SD>NF) : [2 out of 4], [3 out of 4] or [4 out of 4] Abnormal. Vandy 5 th % : [2 out of 3] or [3 out of 3] Abnormal.

Criterion Comparison: % of Subjects Whose DPOAEs All were WNL 6 52% 36% 56% 48% 52% 44% Right Left Both 1 9 8 7 6 5 4 28% 28% 24% 28% 3 2 2SD <3 SNR <6 SNR 8% 1SD 8% 4% 4% 5th %ile 4% 4% 6>(2SD>NF) 1

Discussion and Conclusions The current data suggest that the criteria which result in the largest number of identified DPOAE abnormalities are: Amplitudes less than 6 db above 2 SD above the noise floor Criterion can be calculated easily by each facility for its own specific protocol. Criterion is therefore appropriate for the specific VA population and protocol being used. Amplitudes below the Vanderbilt Data Set 5 th percentile. Criterion optimally should be applied only when the facility uses the identical protocol. Criterion may not be appropriate for VA population. CAVEAT: Neither criterion has been applied to a normal-hearing, agematched, non-tinnitus VA population for determination of its specificity.

Criteria Specificity: Examples Granjeiro et al, 28 (Otolaryngology - Head & Neck Surgery): abnormal in 68.4% of WNL tinnitus subjects and in 5 of WNL non-tinnitus subjects. Onishi et al, 24 (International Tinnitus Journal): abnormal in 61.3% of WNL tinnitus subjects and in 3.6% of WNL non-tinnitus subjects. Criterion: 6 db > (2SD > NF) 25 2 15 25 25 1 2 2 3 2 15 15 1 1 1 5 5 5-5 -5-5 -1-1 -1-15 -15-15 -2-25 -3 Left Ear Right Ear 6 db > (2SD > NF) 75 131 1453 216 2859 3984 5672 816-2 -25-3 Left Ear Right Ear 6 db > (2SD > NF) 75 131 1453 216 2859 3984 5672 816-2 -25-3 Left Ear Right Ear 6 db > (2SD > NF) 75 131 1453 216 2859 3984 5672 816

Criteria Specificity: Examples Granjeiro et al, 28 (Otolaryngology - Head & Neck Surgery): abnormal in 68.4% of WNL tinnitus subjects and in 5 of WNL non-tinnitus subjects. Onishi et al, 24 (International Tinnitus Journal): abnormal in 61.3% of WNL tinnitus subjects and in 3.6% of WNL non-tinnitus subjects. Criterion: Vanderbilt 5 th %ile 25 2 15 25 25 1 2 2 3 2 15 15 1 1 1 5 5 5-5 -5-5 -1-1 -1-15 -15-15 -2-25 -3 Left Ear Right Ear Vandy 5th % 75 131 1453 216 2859 3984 5672 816-2 -25-3 Left Ear Right Ear Vandy 5th % 75 131 1453 216 2859 3984 5672 816-2 -25-3 Left Ear Right Ear Vandy 5th % 75 131 1453 216 2859 3984 5672 816

Discussion and Conclusions Most DPOAE interpretation criteria have been published for hearing screening purposes rather than for determination of OHC status although exceptions exist. Most studies that have explored DPOAEs in normal-hearing tinnitus patients provide comparisons to normal-hearing non-tinnitus subjects rather than absolute norms for determination of normal or abnormal OHC motility. Although DPOAE equipment may overlay normative criteria on DP-grams for reference, the specific population and protocol comprising those norms may differ significantly from actual patients and the clinical protocol being utilized. Obtaining and utilizing normative data obtained for specific DPOAE device(s) in specific facilities is optimal but difficult to achieve in the VA system.

Discussion and Conclusions Various criteria result in substantial differences in the identification of DPOAE abnormalities. Although abnormal DPOAEs were identified at various frequencies for most of these normalhearing tinnitus subjects, the inconsistency of those abnormalities among subjects, combined with the fact that abnormal DPOAEs among normal-hearing non-tinnitus are regularly observed, renders DPOAEs minimally useful, if at all, in the routine evaluation of normal-hearing tinnitus patients. In fact, if abnormal DPOAEs may be observed in 5 of normal-hearing non-tinnitus subjects and 68% of age-matched normal-hearing tinnitus subjects (Granjeiro et al, 28), standard DPOAEs may be unsuitable for routine use in the differentiation of normal-hearing tinnitus patients from normal-hearing non-tinnitus patients.

Questions or Comments? Steve Benton, Au.D. VA Medical Center Decatur, GA 333 Handouts may be requested via email: steve.benton@va.gov