Modernising speech audiometry: using a smartphone application to test word recognition.

OBJECTIVE: This study aimed to develop and assess a method to measure word recognition abilities using a smartphone application (App) connected to an audiometer. DESIGN: Word lists were recorded in South African English and Afrikaans. Analyses were conducted to determine the effect of hardware used for presentation (computer, compact-disc player, or smartphone) on the frequency content of recordings. An Android App was developed to enable presentation of recorded materials via a smartphone connected to the auxiliary input of the audiometer. Experiments were performed to test feasibility and validity of the developed App and recordings. STUDY SAMPLE: Participants were 100 young adults (18-30 years) with pure tone thresholds ≤15 dB across the frequency spectrum (250-8000 Hz). RESULTS: Hardware used for presentation had no significant effect on the frequency content of recordings. Listening experiments indicated good inter-list reliability for recordings in both languages, with no significant differences between scores on different lists at each of the tested intensities. Performance-intensity functions had slopes of 4.05%/dB for English and 4.75%/dB for Afrikaans lists at the 50% point. CONCLUSIONS: The developed smartphone App constitutes a feasible and valid method for measuring word recognition scores, and can support standardisation and accessibility of recorded speech audiometry.

Wideband acoustic immittance for assessing middle ear functioning for preterm neonates in the neonatal intensive care unit.

BACKGROUND: The primary aim of newborn hearing screening is to detect permanent hearing loss. Because otoacoustic emissions (OAEs) and automated auditory brainstem response (AABR) are sensitive to hearing loss, they are often used as screening tools. On the other hand, false-positive results are most often because of transient outer- and middle ear conditions. Wideband acoustic immittance (WAI), which includes physical measures known as reflectance and absorbance, has shown potential for accurate assessment of middle ear function in young infants. OBJECTIVE: The main objective of this study was to determine the feasibility of WAI as a diagnostic tool for assessing middle ear functioning in preterm neonates in the neonatal intensive care unit (NICU) designed for premature and ill neonates. A further objective was to indicate the difference between the reflectance values of tones and click stimuli. METHOD: Fifty-six at-risk neonates (30 male and 26 female), with a mean age at testing of 35.6 weeks (range: 32-37 weeks) and a standard deviation of 1.6 from three private hospitals, who passed both the distortion product otoacoustic emission (DPOAE) and AABR tests, were evaluated prior to discharge from the NICU. Neonates who presented with abnormal DPOAE and AABR results were excluded from the study. WAI was measured by using chirp and tone stimuli. In addition to reflectance, the reflectance area index (RAI) values were calculated. RESULTS: Both tone and chirp stimuli indicated high-power reflectance values below a frequency of 1.5 kHz. Median reflectance reached a minimum of 0.67 at 1 kHz - 2 kHz but increased to 0.7 below 1 kHz and 0.72 above 2 kHz for the tone stimuli. For chirp stimuli, the median reflectance reached a minimum of 0.51 at 1 kHz - 2 kHz but increased to 0.68 below 1 kHz and decreased to 0.5 above 2 kHz. A comparison between the present study and previous studies on WAI indicated a substantial variability across all frequency ranges. CONCLUSION: These WAI measurements conducted on at-risk preterm NICU neonates (mean age at testing: 35.6 weeks, range: 32-37 weeks) identified WAI patterns not previously reported in the literature. High reflective values were obtained across all frequency ranges. The age of the neonates when tested might have influenced the results. The neonates included in the present study were very young preterm neonates compared to the ages of neonates in previous studies. WAI measured in at-risk preterm neonates in the NICU was variable with environmental and internal noise influences. Transient conditions affecting the sound-conduction pathway might have influenced the results. Additional research is required to investigate WAI testing in ears with and without middle ear dysfunction. The findings of the current study imply that in preterm neonates it was not possible to determine the feasibility of WAI as a diagnostic tool to differentiate between ears with and without middle ear pathology.

Affordable headphones for accessible screening audiometry: An evaluation of the Sennheiser HD202 II supra-aural headphone.

OBJECTIVE: Evaluation of the Sennheiser HD 202 II supra-aural headphones as an alternative headphone to enable more affordable hearing screening. DESIGN: Study 1 measured the equivalent threshold sound pressure levels (ETSPL) of the Sennheiser HD 202 II. Study 2 evaluated the attenuation of the headphones. Study 3 determined headphone characteristics by analyzing the total harmonic distortion (THD), frequency response and force of the headband. STUDY SAMPLE: Twenty-five participants were included in study 1 and 15 in study 2 with ages ranging between 18 and 25. No participants were involved in study 3. RESULTS: The Sennheiser HD 202 II ETSPLs (250-16000 Hz) showed no significant effects on ETSPL for ear laterality, gender or age. Attenuation was not significantly different (p > 0.01) to TDH 39 except at 8000 Hz (p < 0.01). Maximum permissible ambient noise levels (MPANL) were specified accordingly. The force of the headband was 3.1N. THD measurements showed that between 500 and 8000 Hz intensities of 90 dB HL and higher can be reached without THD >3%. CONCLUSION: Sennheiser HD 202 II supra-aural headphones can be used as an affordable headphone for screening audiometry provided reported MPANLs, maximum intensities and ETSPL values are employed.

Clinical validation of automated audiometry with continuous noise-monitoring in a clinically heterogeneous population outside a sound-treated environment.

OBJECTIVE: Examine the accuracy of automated audiometry in a clinically heterogeneous population of adults using the KUDUwave automated audiometer. DESIGN: Prospective accuracy study. Manual audiometry was performed in a sound-treated room and automated audiometry was not conducted in a sound-treated environment. STUDY SAMPLE: 42 consecutively recruited participants from a tertiary otolaryngology department in Western Australia. RESULTS: Absolute mean differences ranged between 5.12-9.68 dB (air-conduction) and 8.26-15 dB (bone-conduction). A total of 86.5% of manual and automated 4FAs were within 10 dB (i.e. ±5 dB); 94.8% were within 15 dB. However, there were significant (p < 0.05) differences between automated and manual audiometry at 250, 500, 1000, and 2000 Hz (air-conduction) and 500 and 1000 Hz (bone-conduction). The effect of age (≥55 years) on accuracy (p = 0.014) was not significant on linear regression (p > 0.05; R(2) =( ) 0.11). The presence of a hearing loss (better ear ≥26 dB) did not significantly affect accuracy (p = 0.604; air-conduction), (p = 0.218; bone-conduction). CONCLUSIONS: This study provides clinical validation of automated audiometry using the KUDUwave in a clinically heterogeneous population, without the use of a sound-treated environment. Whilst threshold variations were statistically significant, future research is needed to ascertain the clinical significance of such variation.

Smartphone threshold audiometry in underserved primary health-care contexts.

OBJECTIVE: To validate a calibrated smartphone-based hearing test in a sound booth environment and in primary health-care clinics. DESIGN: A repeated-measure within-subject study design was employed whereby air-conduction hearing thresholds determined by smartphone-based audiometry was compared to conventional audiometry in a sound booth and a primary health-care clinic environment. STUDY SAMPLE: A total of 94 subjects (mean age 41 years ± 17.6 SD and range 18-88; 64% female) were assessed of whom 64 were tested in the sound booth and 30 within primary health-care clinics without a booth. RESULTS: In the sound booth 63.4% of conventional and smartphone thresholds indicated normal hearing (≤15 dBHL). Conventional thresholds exceeding 15 dB HL corresponded to smartphone thresholds within ≤10 dB in 80.6% of cases with an average threshold difference of -1.6 dB ± 9.9 SD. In primary health-care clinics 13.7% of conventional and smartphone thresholds indicated normal hearing (≤15 dBHL). Conventional thresholds exceeding 15 dBHL corresponded to smartphone thresholds within ≤10 dB in 92.9% of cases with an average threshold difference of -1.0 dB ± 7.1 SD. CONCLUSIONS: Accurate air-conduction audiometry can be conducted in a sound booth and without a sound booth in an underserved community health-care clinic using a smartphone.

Development and validation of a smartphone-based digits-in-noise hearing test in South African English.

OBJECTIVE: The objective of this study was to develop and validate a smartphone-based digits-in-noise hearing test for South African English. DESIGN: Single digits (0-9) were recorded and spoken by a first language English female speaker. Level corrections were applied to create a set of homogeneous digits with steep speech recognition functions. A smartphone application was created to utilize 120 digit-triplets in noise as test material. An adaptive test procedure determined the speech reception threshold (SRT). Experiments were performed to determine headphones effects on the SRT and to establish normative data. STUDY SAMPLE: Participants consisted of 40 normal-hearing subjects with thresholds ≤15 dB across the frequency spectrum (250-8000 Hz) and 186 subjects with normal-hearing in both ears, or normal-hearing in the better ear. RESULTS: The results show steep speech recognition functions with a slope of 20%/dB for digit-triplets presented in noise using the smartphone application. The results of five headphone types indicate that the smartphone-based hearing test is reliable and can be conducted using standard Android smartphone headphones or clinical headphones. CONCLUSION: A digits-in-noise hearing test was developed and validated for South Africa. The mean SRT and speech recognition functions correspond to previous developed telephone-based digits-in-noise tests.

False air-bone gaps at 4 kHz in listeners with normal hearing and sensorineural hearing loss.

OBJECTIVE: This report presents data from four studies to examine standard bone-conduction reference equivalent threshold force levels (RETFL), especially at 4 kHz where anomalous air-bone gaps are common. DESIGN: Data were mined from studies that obtained air- and bone-conduction thresholds from normal-hearing and sensorineural hearing loss (SNHL) participants, using commercial audiometers and standard audiometric transducers. STUDY SAMPLE: There were 249 normal-hearing and 188 SNHL participants. RESULTS: (1) Normal-hearing participants had small air-bone gaps at 0.5, 1.0, and 2.0 kHz (-1.7 to 0.3 dB) and larger air-bone gaps at 4 kHz (10.6 dB). (2) SNHL participants had small air-bone gaps at 0.5, 1.0, and 2.0 kHz (-0.7 to 1.7 dB) and a larger air-bone gap at 4 kHz (14.1 dB). (3) The 4-kHz air-bone gap grew with air-conduction threshold from 10.1 dB when the air-conduction threshold was 5-10 dB HL to 21.1 dB when the air-conduction threshold was greater than 60 dB. (4) With the 4-kHz RETFL corrected by the average SNHL air-bone gap, the relationship between RETFL and frequency is linear with a slope of - 12 dB per octave. CONCLUSIONS: The 4-kHz air-bone gaps for listeners with SNHL could be avoided by adjusting the 4-kHz RETFL by - 14.1 dB.

Clinical validation of the AMTAS automated audiometer.

OBJECTIVE: To validate the air- and bone-conduction AMTAS automated audiometry system. DESIGN: Prospective study. Test-retest reliability was determined by assessing adults with AMTAS air- and bone-conduction audiometry. Accuracy was determined by comparing AMTAS and manual audiometry conducted on adults. AMTAS testing was conducted in a quiet room and manual audiometry in a sound booth. STUDY SAMPLE: Ten participants for test-retest reliability tests and 44 participants to determine accuracy were included. Participants had varying degrees of hearing loss. RESULTS: For test-retest reliability the overall difference in air-conduction hearing thresholds (n = 119) was 0.5 dB. The spread of differences (standard deviation of absolute differences) was 4.9 dB. For bone-conduction thresholds (n = 99) the overall difference was - 0.2 dB, and the spread of differences 4.5 dB. For accuracy the overall difference in air-conduction hearing thresholds (n = 509) between the two techniques was 0.1 dB. The spread of differences was 6.4 dB. For bone-conduction thresholds (n = 295) the overall difference was 0 dB, and the spread of differences 7.7 dB. CONCLUSIONS: Variations between air- and bone-conduction audiometry for automated and manual audiometry were within normally accepted limits for audiometry. However, AMTAS thresholds were elevated but not significantly different compared to other contemporary studies that included an automated audiometer.

Hearing-aid assembly management among adults from culturally and linguistically diverse backgrounds: toward the feasibility of self-fitting hearing aids.

OBJECTIVE: The purpose of the study was twofold: (1) to assess the ability of hearing-impaired adults in the developing world to independently and accurately assemble a pair of hearing aids by following instructions that were written and illustrated according to best-practice health literacy principles; and (2) to determine which factors influence independent and accurate task completion. DESIGN: Correlational study. STUDY SAMPLE: Forty South African and 40 Chinese adults with a hearing loss and their partners. The participant group included 42 females and 38 males ranging in age from 32 to 92 years. RESULTS: Ninety-five percent of South African and 60% of Chinese participants completed the assembly task, either on their own or with assistance from their partners. Better health literacy, younger age, and a more prestigious occupation were significantly associated with independent task completion for the South African and Chinese participants. Task accuracy was significantly linked to higher levels of cognitive function among South African participants, while a paucity of valid data prevented an analysis of accuracy from being conducted with the Chinese data. CONCLUSION: Individuals of diverse backgrounds can manage the self-fitting hearing-aid assembly task as long as health literacy levels and cultural differences are considered.

Auditory and otological manifestations in adults with HIV/AIDS.

OBJECTIVES: This study describes the prevalence and nature of auditory and otological manifestations in adults with HIV/AIDS through clinical examinations and self-reported symptoms across stages of disease progression. DESIGN: Descriptive cross-sectional group design. STUDY SAMPLE: Two hundred HIV positive adult patients (56.5% male; 43.5% female; mean age: 37.99 ± 6.66 years) attending the Infectious Disease Clinic of a tertiary referral hospital in Pretoria, South Africa were included. Patients were interviewed, medical files were reviewed, and clinical examinations, including otoscopy, tympanometry, pure-tone audiometry, and distortion product otoacoustic emissions, were conducted. A matched HIV negative control group was used to compare hearing loss prevalence. RESULTS: Tinnitus (26%), vertigo (25%) hearing loss (27.5%), otalgia (19%), and ear canal pruritis (38%) were prevalent self-reported symptoms. Abnormalities in otoscopy, tympanometry, and otoacoustic emissions were evident in 55%, 41%, and 44% of patients respectively. Pure-tone average (PTA) hearing loss > 25 dBHL was evident in 14% of patients and 39% for hearing loss > 15 dBHL (PTA). Significant differences across average thresholds in the HIV positive and HIV negative control group was present. An increase in self reported vertigo, self reported hearing loss, OAE abnormalities, and hearing loss (PTA > 15 dBHL and PTA > 25 dBHL) was seen with disease progression but was not statistically significant. A significant increase (p <.05) in sensorineural hearing loss was however evident with disease progression. CONCLUSIONS: Auditory and otological symptoms are more common in patients with HIV with a general increase of symptoms, especially sensorineural hearing loss, towards advanced stages of disease progression.

Validity of diagnostic pure-tone audiometry without a sound-treated environment in older adults.

OBJECTIVE: To investigate the validity of diagnostic pure-tone audiometry in a natural environment using a computer-operated audiometer with insert earphones covered by circumaural earcups incorporating real-time monitoring of environmental noise. DESIGN: A within-subject repeated measures design was employed to compare air (250 to 8000 Hz) and bone (250 to 4000 Hz) conduction pure-tone thresholds, measured in retirement facilities, with thresholds measured in a sound-treated booth. STUDY SAMPLE: One hundred and forty-seven adults (average age 76 ± 5.7 years) were evaluated. Pure-tone averages were ≥ 25 dB in 59%, mildly (> 40 dB) elevated in 23%, and moderately (> 55 dB) elevated in 6% of ears. RESULTS: Air-conduction thresholds (n = 2259) corresponded within 0 to 5 dB in 95% of all comparisons between the two test environments. Bone-conduction thresholds (n = 1669) corresponded within 0 to 5 dB in 86% of comparisons. Average threshold differences (- 0.6 to 1.1) and standard deviations (3.3 to 5.9) were within typical test-retest reliability limits. Thresholds recorded showed no statistically significant differences (paired samples t-test:p > 0.01) except at 8000 Hz in the left ear. CONCLUSION: Valid diagnostic pure-tone audiometry can be performed in a natural environment with recently developed technology, offering the possibility of access to diagnostic audiometry in communities where sound-treated booths are unavailable.

Auditory steady-state responses to bone conduction stimuli in children with hearing loss.

OBJECTIVE: The auditory steady-state response (ASSR) to air-conduction (AC) stimuli has been widely incorporated into audiological test-batteries for the pediatric population. The current understanding of ASSR to bone conduction (BC) stimuli, however, is more limited, especially in the case of infants and children. There are few reports on ASSR thresholds to BC stimuli in infants and young children, and none for infants or children with hearing loss. The objective of this study was to investigate BC ASSR thresholds in young children with normal hearing and various types and degrees of hearing loss. METHODS: AC and BC ASSR thresholds are reported for 48 young children (mean age+/-SD=2.8+/-1.9 years; age range=0.25-11.5 years; 23 female). Hearing status was classified by assessing all children with a comprehensive test battery including tympanometry, diagnostic distortion-product otoacoustic emissions, click-evoked AC auditory brainstem response, AC and BC ASSR thresholds, and an otologic examination. The subjects were assigned to the categories normal hearing, conductive loss, and sensorineural loss (mild-to-moderate or severe-to-profound), for group analysis. AC and BC ASSR stimuli (carrier frequencies: 0.25-4 kHz; 67-95 Hz modulation rates; 100% amplitude and 10% frequency modulated) were presented using the GSI Audera system. RESULTS: Minimum levels at which spurious BC ASSR occur were established in the group of children with severe-to-profound sensorineural hearing loss (25, 40, 60, 60 and 60 dB for 0.25, 0.5, 1, 2, and 4 kHz, respectively). Children with normal hearing presented mean (1 SD) BC ASSR thresholds of 19 (9), 18 (7), 16 (11), 24 (7), and 26 (8) dB HL at 0.25, 0.5, 1, 2, and 4 kHz, respectively. Significantly lower thresholds (p<0.0001) were obtained for 0.25, 0.5 and 1 kHz than for 2 and 4 kHz. At 0.25 kHz, 39% of thresholds were at the minimum level of spurious response occurrence. More than half (54%) of the BC thresholds in the group with mild-to-moderate sensorineural hearing loss were recorded at or above the minimum levels at which spurious response occurred. In children with conductive hearing loss, the average BC ASSR thresholds corresponded closely to those in the normal hearing group except at 1 kHz and revealed an air-bone gap. CONCLUSIONS: Spurious bone conduction ASSR responses limit the intensity range for which the technique may be employed in infants and children, especially at lower frequencies. Consequently, the 0.25 kHz stimulus is not recommended for clinical use. In infants and young children, sensorineural hearing loss of a moderate or greater degree in the high frequencies (1-4 kHz), and of a mild or greater degree in the low frequencies (0.5 kHz), cannot be quantified using BC ASSR. This is due to the presence of the stimulus artifact. In cases of conductive hearing loss, BC ASSR can effectively quantify sensory hearing between 0.5 and 4 kHz, but interpretations must be made cautiously within the limitations of stimulus artifact occurrence across frequencies.

Identifying hearning loss by means of iridology

Isolated reports of hearing loss presenting as markings on the iris exist; but to date the effectiveness of iridology to identify hearing loss has not been investigated. This study therefore aimed to determine the efficacy of iridological analysis in the identification of moderate to profound sensorineural hearing loss in adolescents. A controlled trial was conducted with an iridologist; blind to the actual hearing status of participants; analyzing the irises of participants with and without hearing loss. Fifty hearing impaired and fifty normal hearing subjects; between the ages of 15 and 19 years; controlled for gender; participated in the study. An experienced iridologist analyzed the randomised set of participants' irises. A 70correct identification of hearing status was obtained by iridological analyses with a false negative rate of 41compared to a 19false positive rate. The respective sensitivity and specificity rates therefore came to 59and 81. Iridological analysis of hearing status indicated a statistically significant relationship to actual hearing status (P 0.05). Although statistically significant sensitivity and specificity rates for identifying hearing loss by iridology were not comparable to those of traditional audiological screening procedures

Identifying hearing loss by means of iridology.

Isolated reports of hearing loss presenting as markings on the iris exist, but to date the effectiveness of iridology to identify hearing loss has not been investigated. This study therefore aimed to determine the efficacy of iridological analysis in the identification of moderate to profound sensorineural hearing loss in adolescents. A controlled trial was conducted with an iridologist, blind to the actual hearing status of participants, analyzing the irises of participants with and without hearing loss. Fifty hearing impaired and fifty normal hearing subjects, between the ages of 15 and 19 years, controlled for gender, participated in the study. An experienced iridologist analyzed the randomised set of participants' irises. A 70% correct identification of hearing status was obtained by iridological analyses with a false negative rate of 41% compared to a 19% false positive rate. The respective sensitivity and specificity rates therefore came to 59% and 81%. Iridological analysis of hearing status indicated a statistically significant relationship to actual hearing status (P < 0.05). Although statistically significant sensitivity and specificity rates for identifying hearing loss by iridology were not comparable to those of traditional audiological screening procedures.