Australian Defence Force Global Health Engagement through malaria and other vectorborne disease programmes in the Pacific and Southeast Asia

Global Health Engagement is one method employed by the Australian Defence Force (ADF) in pursuit of its objectives to shape Australia's strategic environment and to deter actions against Australia's interests. Two recent examples of such engagements are malaria mitigation programmes led by the ADF Malaria and Infectious Disease Institute in partnership with the Vietnam People's Army and the Papua New Guinea Defence Force. Both programmes were designed with extensive collaboration with host nation stakeholders, empowered local institutions and governance systems, built the capacity of the host nation with the aim of achieving independence from Australian support and met the strategic policy requirements of all nations involved. Process and outcome measures were built into both programmes, providing partner nations with the necessary assurance that funding was being used effectively. The long-term nature of each programme engendered personal trust between individuals and cultural understanding between military units. Recognising the value of formal education in the design and conduct of such programmes, ADF officers participate as students and instructors in the US Uniformed University of the Health Sciences course in Global Health and Global Health Engagement. Critically, this educational opportunity is afforded to future leaders in all professions related to health, including clinicians, military health planners and commanders. While an essential prerequisite to Global Health Engagement Programmes is their technical viability and validity, the most important key to success in the military context is a widespread understanding of how they achieve desired strategic effects for all involved.

Serological evidence of possible high levels of undetected transmission of Zika virus among Papua New Guinea military personnel, 2019

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In total, 208 Papua New Guinea military personnel (PNGMP) participated in this survey.

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The overall seroprevalence of Zika virus IgG using indirect enzyme-linked immunosorbent assay was 67%.

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The overall seroprevalence of Zika virus by neutralizing assay was 65%.

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Five of 19 anti-ZIKV-IgM⁺ samples met the criteria of the World Health Organization for confirmed ZIKV infection.

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An undetected Zika virus outbreak may have occurred in PNGMP in 2019.

Objectives

The Papua New Guinea (PNG) Health Department retrospectively reported six cases of Zika virus (ZIKV) from a cohort of febrile patients during outbreaks of dengue and malaria in 2016. However, the transmission of ZIKV remains unclear due to lack of testing capability. This study aimed to determine the level of immunity to ZIKV among PNG military personnel (PNGMP) in 2019.

Methods

Sera of 208 PNGMP recruited in April 2019 was tested for the presence of anti-ZIKV immunoglobulin G (IgG) and M (IgM) antibodies using Euroimmun IgG/IgM detection kits, and anti-ZIKV neutralizing antibody (Nab) against a ZIKV African strain on all anti-ZIKV-IgG/IgM⁺ samples.

Results

Anti-ZIKV seropositivity of these sera was as follows: IgG, 67%; IgM, 9%; and Nab, 65%. Five of 19 anti-ZIKV-IgM⁺ samples had anti-ZIKV-Nab titres ≥20, as well as an anti-ZIKV-Nab titre ratio ≥4 compared with the Nab titres of four anti-dengue serotypes, so met the criteria of the World Health Organization (WHO) for confirmed ZIKV infection.

Conclusions

The prevalence of anti-ZIKV-Nab of 65% suggests that there are high levels of ZIKV exposure among PNGMP. Five of the 19 anti-ZIKV-IgM⁺ samples met the WHO criteria for confirmed ZIKV infection, suggesting a recent undetected outbreak in PNGMP. These results provide better understanding of the current ZIKV epidemic status in PNGMP.

Seroprevalence of chikungunya virus among military personnel in Papua New Guinea, 2019

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The seroprevalence of chikungunya virus was investigated among military personnel in Papua New Guinea.

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The seroprevalence of anti-chikungunya virus immunoglobulin G antibodies on enzyme-linked immunosorbent assay was 47%.

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The seroprevalence of anti-chikungunya virus neutralizing antibodies was 35%.

Objectives

The first outbreak of chikungunya virus (CHIKV) was reported in West Sepik, Papua New Guinea (PNG) in June 2012, and spread rapidly throughout PNG. CHIKV imported from PNG to Queensland has been reported occasionally, but transmission of CHIKV in PNG remains unclear due to the lack of testing capability. This study investigated the degree of CHIKV exposure among PNG military personnel (PNGMP) in 2019, 7 years after its first emergence.

Methods

Sera of 204 PNGMP recruited in April 2019 was tested for the presence of anti-CHIKV immunoglobulin G (IgG) antibodies using a commercially available IgG detection kit, and anti-CHIKV neutralizing antibodies against a CHIKV Reunion strain using a neutralizing assay.

Results

Anti-CHIKV seropositivity of the sera was 47% and 35%, respectively, using the enzyme-linked immunosorbent assay (ELISA) and neutralizing assay. Five percent (n=11) of samples were found to be IgG negative or borderline, but neutralizing antibody positive.

Conclusions

The prevalence of anti-CHIKV neutralizing antibody of 35% suggests that CHIKV infection has become endemic among PNGMP. Current commercially available CHIKV ELISA detection kits may not be suitable for diagnostic purposes in multiple alphavirus endemic areas such as PNG, due to serological cross-reactivity among alphaviruses. Re-emergence of CHIKV in PNGMP is possible.

Lymphatic filariasis epidemiology in Samoa in 2018: Geographic clustering and higher antigen prevalence in older age groups

BACKGROUND

Samoa conducted eight nationwide rounds of mass drug administration (MDA) for lymphatic filariasis (LF) between 1999 and 2011, and two targeted rounds in 2015 and 2017 in North West Upolu (NWU), one of three evaluation units (EUs). Transmission Assessment Surveys (TAS) were conducted in 2013 (failed in NWU) and 2017 (all three EUs failed). In 2018, Samoa was the first in the world to distribute nationwide triple-drug MDA using ivermectin, diethylcarbamazine, and albendazole. Surveillance and Monitoring to Eliminate LF and Scabies from Samoa (SaMELFS Samoa) is an operational research program designed to evaluate the effectiveness of triple-drug MDA on LF transmission and scabies prevalence in Samoa, and to compare the usefulness of different indicators of LF transmission. This paper reports results from the 2018 baseline survey and aims to i) investigate antigen (Ag) prevalence and spatial epidemiology, including geographic clustering; ii) compare Ag prevalence between two different age groups (5-9 years versus ≥10 years) as indicators of areas of ongoing transmission; and iii) assess the prevalence of limb lymphedema in those aged ≥15 years.

METHODS

A community-based cluster survey was conducted in 30 randomly selected and five purposively selected clusters (primary sampling units, PSUs), each comprising one or two villages. Participants were recruited through household surveys (age ≥5 years) and convenience surveys (age 5-9 years). Alere Filariasis Test Strips (FTS) were used to detect Ag, and prevalence was adjusted for survey design and standardized for age and gender. Adjusted Ag prevalence was estimated for each age group (5-9, ≥10, and all ages ≥5 years) for random and purposive PSUs, and by region. Intraclass correlation (ICC) was used to quantify clustering at regions, PSUs, and households.

RESULTS

A total of 3940 persons were included (1942 children aged 5-9 years, 1998 persons aged ≥10 years). Adjusted Ag prevalence in all ages ≥5 years in randomly and purposively selected PSUs were 4.0% (95% CI 2.8-5.6%) and 10.0% (95% CI 7.4-13.4%), respectively. In random PSUs, Ag prevalence was lower in those aged 5-9 years (1.3%, 95% CI 0.8-2.1%) than ≥10 years (4.7%, 95% CI 3.1-7.0%), and poorly correlated at the PSU level (R-square = 0.1459). Adjusted Ag prevalence in PSUs ranged from 0% to 10.3% (95% CI 5.9-17.6%) in randomly selected and 3.8% (95% CI 1.3-10.8%) to 20.0% (95% CI 15.3-25.8%) in purposively selected PSUs. ICC for Ag-positive individuals was higher at households (0.46) compared to PSUs (0.18) and regions (0.01).

CONCLUSIONS

Our study confirmed ongoing transmission of LF in Samoa, in accordance with the 2017 TAS results. Ag prevalence varied significantly between PSUs, and there was poor correlation between prevalence in 5-9 year-olds and older ages, who had threefold higher prevalence. Sampling older age groups would provide more accurate estimates of overall prevalence, and be more sensitive for identifying residual hotspots. Higher prevalence in purposively selected PSUs shows local knowledge can help identify at least some hotspots.

Nonrestorative sleep scale: reliable and valid for the Chinese population

PURPOSE

To conduct a linguistic and psychometric evaluation of a Chinese version of the Nonrestorative Sleep Scale (NRSS).

METHODS

The Chinese NRSS was created from a standard forward-backward translation and trialed on 10 Chinese adults. Telephone interviews were then conducted with 100 adults, who completed the Chinese NRSS, the Pittsburgh Sleep Quality Index (PSQI), the Athens Insomnia Scale (AIS), the Center for Epidemiological Studies Depression Scale (CES-D), and the Toronto Hospital Alertness Test (THAT). A household survey was conducted with 20 subjects, followed by a confirmatory factor analysis (CFA), and a bifactor model was developed to evaluate the reliability and validity of the NRSS.

RESULTS

The bifactor model had the root mean square error of approximation (RMSEA), standardized root mean square residual (SRMR), and comparative fit index (CFI) of 0.06, 0.06, and 0.97, respectively. Convergent validity was shown from the moderate associations with PSQI (r = - 0.66, P < 0.01), AIS (r = - 0.65, P < 0.01), CES-D (r = - 0.54, P < 0.01), and THAT (r = 0.68, P < 0.01). The coefficient omega (0.92), omega hierarchical (0.81), factor determinacy (0.93), H value (0.91), explained common variance (0.63), and percentage of uncontaminated correlations (0.80) derived from the bifactor CFA supported the essential unidimensionality of NRSS.

CONCLUSIONS

The Chinese NRSS is a valid and reliable essential unidimensional tool for the assessment of nonrestorative sleep in the Chinese population.

Chinese Attitudes toward Cleft Lip and Palate: Effects of Personal Contact

Objective:

The purpose of this study was to investigate the effect of personal contact on the attitudes of individuals towards persons with cleft lip and palate (CLP) and the possible cultural differences in these attitudes for Chinese respondents living in Hong Kong.

Design:

Chinese parent, teacher, and employer groups were administered a cleft lip and palate attitudinal questionnaire and the Scale of Attitudes Toward Disabled Persons inventory.

Subjects:

Thirty-nine parents of children with CLP, 27 teachers of children with CLP, and 37 employers with no previous contact with individuals with CLP participated in the study.

Results:

The results showed significant intergroup differences on several items involving beliefs concerning emotional health, social development, and employment-related barriers for individuals with CLP, and whether such individuals should seek nonmedical help to treat speech problems. Employers showed a comparatively less favorable attitude to persons with CLP than the two other groups.

Conclusion:

Parent, teacher, and employer groups in the Chinese community studied showed differences in their attitudes towards individuals with CLP. The findings suggest the need for further community health education to help develop more positive attitudes towards disabled persons in general, as well as programs targeted at reducing negative stereotyping of adults and children with CLP.

Assessment of the burden of human African trypanosomiasis by rapid participatory appraisal in three high-risk villages in Urambo District, Northwest Tanzania

BACKGROUND

The public health and socio-economic burden of Human African Trypanosomiasis (HAT) in East Africa is not well documented. Understanding the epidemiology and impact of HAT in such settings is difficult due to a lack of robust surveillance and reporting systems, restricting evidence-based policy development and contributing to the continued neglect of this disease.

OBJECTIVE

To investigate the burden of HAT in Urambo District, Tanzania in order to inform future public health policy.

METHODS

A rapid participatory appraisal (RPA) using a combination of qualitative and quantitative methods was conducted, that included key informant interviews, hospital record analysis, and tools adapted from participatory learning and action.

RESULTS

Three villages adjacent to Ugala Game Reserve appeared to be the most affected. High levels of under-reporting were noted due to a lack of diagnostic tools at peripheral health care facilities and limited access to specialist services. Community stakeholders perceived the health and socio-economic burden of HAT to be similar to that of malaria.

CONCLUSION

The burden of HAT in remote rural communities is difficult to capture through routine surveillance systems alone. The RPA represents an efficient mechanism for engaging communities in public health action for trypanosomiasis control in northwest Tanzania.

Hearing screening for school children: comparison of low-cost, computer-based and conventional audiometry

BACKGROUND

There is a need to develop affordable but effective audiometric screening equipment, particularly for use in low-income countries. With advances in computer technology, low-cost computer-based audiometer software has been developed. However, the efficacy of computer-based audiometers in hearing screening and diagnostic assessment requires investigation. The purpose of this study was to evaluate the accuracy of a low-cost, computer-based audiometric system in a school-based hearing screening programme.

METHODS

Eighty children were screened using the computer-based audiometer and with a conventional pure tone screening audiometer. Overall refer rates, as well as frequency and age effects on the accuracy of the computer-based audiometer, were considered.

RESULTS

There was a significant relationship between the low-cost, computer-based audiometer and a conventional pure tone audiometer when a 40 dBHL refer criterion was used in school hearing screening and when test results at 500 Hz were excluded from analysis. However, background noise effects and software limitations in the computer-based system had major adverse effects on screening performance.

CONCLUSIONS

The study results and preliminary practical experience with the system suggest that, with further software and hardware improvements, a low-cost, computer-based system may well be feasible for routine school screening in developing countries.

Effectiveness of an affordable hearing aid with elderly persons

PURPOSE

his study evaluated the effectiveness of a recently developed, low-cost 'over-the-counter' style hearing aid with elderly people, who had mild to moderate mixed or sensorineural hearing losses. Two aspects were focused upon, objective change in the participants' aided hearing measures and the self-reported performance and benefit obtained from the hearing aid.

METHOD

The hearing aids were trialed by 19 elderly persons over a 3-month period. Aided hearing thresholds and real-ear insertion gain measures were obtained from participants, three questionnaires (the Client-Oriented Scale of Improvement [COSI], the International Outcome Inventory for Hearing Aids [IOI-HA] and the Profile of Hearing Aid Performance--Chinese version [PHAP-C]) were completed, and an open-ended interview was conducted.

RESULTS

Objective tests noted that the trial hearing aid was able to provide appropriate amplification for the elderly participants in this study. The device was rated by the majority of participants as providing benefit, with 16 of the participants (84%) using their hearing aid from at least 1 to over 8 h each day and with all participants considering the low-cost instrument 'worth the trouble' of wearing. Participant ratings of benefit with the IOI-HA were comparable with those obtained in a normative study in which subjects used more expensive conventional hearing aids. Using the COSI questionnaire, participants typically concluded that their hearing improvement with the study device was 'slightly better' to 'better' than without amplification. The PHAP-C questionnaire results indicated that, while wearing their hearing aids, participants experienced difficulties only infrequently in most everyday listening situations. Comments made during open-ended interviews were equally positive and negative, with most negative comments focused on difficulties with either acoustic feedback or background noise annoyance while wearing the hearing instrument.CONCLUSION. Affordable, over-the-counter hearing devices provide a potential opportunity for greater numbers of persons with hearing loss to access amplification and benefit from improved communicative abilities. Further investigation and further development of these instruments is warranted, to provide enhanced rehabilitation outcomes for elderly persons with hearing impairment.

Infant hearing screening: effects of timeline

OBJECTIVES

Universal infant hearing screening using otoacoustic emission and auditory brain-stem response audiometry is widely administered to attain the goals of early identification of, and intervention for hearing impairment. Concerns regarding screening specificity have, however, been raised. False positives may result from vernix occlusion in the ear canal or transient middle ear effusion, and can result in substantial costs to health care systems. The current study investigates the effects of age and time interval between tests on hearing assessment results.

SETTING & PARTICIPANTS

Three hundred and seventeen positive screens from a 2-stage distortion product otoacoustic emission (DPOAE) screening programme in Hong Kong, who subsequently received diagnostic auditory brainstem response (ABR) assessment and monitoring, were investigated.

MAIN OUTCOME MEASURES

Differences in diagnostic ABR results were compared among infants of different ages at tests, and with different time lapses after DPOAE screening. The proportion of those having persistent hearing impairment, conductive loss and impairment of moderate degree or above, were also compared.

RESULTS

A significantly higher rate of normal ABR thresholds (60%versus 24%) was noted in infants assessed after age 50 days, and in infants diagnostically assessed with a time lapse of over 20 days post-DPOAE screening (65%versus 42%).

CONCLUSIONS

Delaying diagnostic ABR assessment may reveal a higher percentage of normal thresholds, and hence probably higher specificity. Time delay may allow for spontaneous resolution of transient outer and middle ear conditions. However, the goals of early identification and intervention, as well as possible parental anxiety with delayed assessment, should also be considered when reviewing infant hearing screening schedules.

Neonatal hearing screening: evaluation of tone-burst and click-evoked otoacoustic emission test criteria

OBJECTIVE

Click-evoked otoacoustic emissions (CEOAEs) are widely used in universal neonatal hearing screening programs. A common finding in many such programs is a relatively high false-positive rate. This is often due to infant physiological noise adversely affecting the emission recording, leading to a "refer" screening outcome. In an attempt to reduce false-positive screening outcomes related to the effects of noise on otoacoustic emission response detection, tone-burst-evoked otoacoustic emissions (TBOAEs) were included in a neonatal hearing screening program because TBOAEs may elicit a greater signal-to-noise ratio than CEOAEs. The research project compared the pass/refer rate for a CEOAE-based test using established pass/refer criteria with the pass/refer rate for screening criteria that were based on TBOAE results alone or on combined CEOAE and TEOAE results.

DESIGN

Neonates were recruited at the Hong Kong Adventist Hospital, and both CEOAEs and TBOAEs were performed. Six passing criteria were used in this study, based on CEOAEs only; CEOAEs plus 1 kHz TBOAEs; CEOAEs plus 2 kHz TBOAEs; CEOAEs plus 3 kHz TBOAEs; CEOAEs plus 1, 2, and 3 kHz TBOAEs; and TBOAEs only.

RESULTS

Data from 298 neonates (546 ears) were obtained. Criteria set 1, using CEOAEs only, demonstrated a pass rate of 79.1%, and 114 ears were referred. Criteria set 2, using CEOAEs together with TBOAEs recorded at 1 kHz, passed 39 more ears than Protocol 1, and the pass rate was 86.3%. Hence, the overall referral rate for total number of screened ears decreased by 7.2 percentage points. Criteria set 3, using CEOAEs together with TBOAEs recorded at 2 kHz, and Criteria set 4, using CEOAEs in conjunction with TBOAEs recorded at 3 kHz, gave pass rates similar to Criteria set 1. Criteria set 5, using TBOAE information at frequencies where CEOAEs were not rated as "pass," raised the pass rate from 79.1 to 87.6%, reducing the overall referral rate by 8.5 percentage points. Criteria set 6, in which neonates were screened with TBOAEs recorded at 1, 2, and 3 kHz, gave a pass rate of 78.4%, similar to results for the CEOAE-only procedure.

CONCLUSIONS

Both Criteria sets 2 and 5, which combined CEOAE and TBOAE recordings, gave significantly higher pass rates than Criteria sets 1, 3, 4, and 6. The results suggest that the introduction of combined CEOAE and TBOAE protocols may assist in the reduction of refer outcomes, and hence the false-positive rates, of neonatal hearing screening programs.

Audiometric configurations of hearing impaired children in Hong Kong: implications for amplification

PURPOSE

Children with hearing loss who require special school placement may have a wide range of audiometric configurations. Since such children will vary in auditory status their amplification requirements may also be diverse. This study examined the audiological records of 231 children attending four schools for hearing impaired children in Hong Kong to gain an understanding of common audiometric patterns found in the school children and their auditory rehabilitation needs.

METHOD

Data on the children's aetiology of hearing loss, hearing status, tympanometric findings and the electroacoustic characteristics of their hearing aids were obtained. For 424 children's ears considered having essentially sensorineural hearing loss, k-means cluster analysis methods were used to categorize audiometric configuration groups.

RESULTS

Cluster analysis that indicated that five distinct audiometric configurations could be found among the school children. Different clusters contained children who had differing amplification needs. The study analysed a number of parameters to check fitting outcomes, including average prescribed gain, frequency-specific measured versus prescribed gain, prescribed frequency response, measured versus prescribed frequency response and the predicted aided thresholds for the children.

CONCLUSION

The amplification needs associated with these five configurations, including recommended prescription gain, maximum power output and possible signal processing strategies, were considered. The clustering algorithm approach proved useful as a means of grouping distinctive audiometric profiles.

Screening for auditory neuropathy in a school for hearing impaired children

OBJECTIVE

Hearing loss in children may be due to a wide variety of pathologies. Recently, use of otoacoustic emission technology has led to identification of auditory neuropathy as a distinct hearing disorder. Children with auditory neuropathy require audiological and educational management that may differ from that required by other hearing impaired students. For this reason, screening for auditory neuropathy may be appropriate for children attending schools for the hearing impaired. The study investigated the utility of using otoacoustic emission measures for school screening of hearing impaired children.

METHODS

In this study, 81 children aged 6-12 years who attended one school for the deaf were screened for indications of auditory neuropathy. Children found to have consistent otoacoustic emissions were given a full diagnostic audiological test battery.

RESULTS

Two children had transient otoacoustic emission results indicating normal outer hair cell function in one or both ears. A follow-up diagnostic assessment for the two positive cases was strongly suggestive of auditory neuropathy.

CONCLUSIONS

There is a need for routine auditory neuropathy screening at schools for hearing impaired children.

Effects of speech babble on transient evoked otoacoustic emissions in normal-hearing adults

The results of transient evoked otoacoustic emissions (TEOAEs) have been found to be adversely affected by noise. However, there are few investigations into the specific effect of background noise on TEOAEs. The purpose of the present study was to determine the effects of increasing levels of speech babble and the recording method on TEOAEs using the ILO88 Otodynamics instrumentation. Subjects were 30 normal-hearing adults (15 males and 15 females), aged between 18 and 32 years. TEOAE recordings were obtained from both ears of each subject under five different levels of speech babble delivered via a loudspeaker in sound field using both the default and Quickscreen methods of data collection. The results indicated that both the whole-wave reproducibility (WWR) and mean signal-to-noise ratio (MSNR), averaged across frequencies from about 2 to 4 kHz, decreased with increasing speech babble levels. The results also showed that the Quickscreen mode was less susceptible to noise than the default mode. The pass percentage, using either WWR > or = 50 percent or an MSNR > or = 3 dB as a pass criterion, also decreased with increasing speech babble levels. Furthermore, the findings indicated that the use of the WWR pass criterion resulted in a high failure rate under high levels of speech babble. In contrast, the MSNR pass criterion was robust to speech babble levels of up to 70 dBA in the Quickscreen mode and 65 dBA in the default setting. The clinical implications of these findings, as applied to non-sound-treated environments, are discussed.

Transient evoked otoacoustic emissions in 6-year-old school children: a normative study

Great potential has recently been demonstrated for the application of transient evoked otoacoustic emissions (TEOAEs) in screening the hearing of school-aged children. The present study aimed to describe the range of TEOAE values obtained from a large cohort of 6-year-old children in school settings. Results indicated significant sex and ear asymmetry effects on signal-to-noise ratio, response, whole wave reproducibility, band reproducibility and noise levels. A prior history of ear infections was also shown to influence response level, whole wave reproducibility and band reproducibility. The sex, ear and history specific normative data tables derived may contribute to future improvements in the accuracy of hearing screening for 6-year-old school children.

Paediatric hearing screening in the community: a comparison of outcomes from transient evoked and distortion product otoacoustic emission measures

The present study aimed to compare TEOAE screening outcomes based on different pass/fail criteria and the outcomes from TEOAE and DPOAE measures in children. For the purpose of the study, the subjects were divided into two age groups: group 1 (n = 36; mean age 2.7 months, SD 1.2), and group 2 (n = 29; mean age 37.5 months, SD 16.3). Results indicated that the agreement of screening outcomes between pass/fail criteria for the TEOAE measure and between TEOAE and DPOAE measures was significantly lower for the younger group than for the older group. The greater variability in the younger age group could be partly attributed to the higher physiological noise produced by young infants. Irrespective of the pass/fail criteria used, the findings of the present study suggest that the OAE outcomes for children with weak OAEs or OAEs obscured by excessive noise were most variable.

The effect of high-pass filtering on TEOAE in 2-month-old infants

The aim of the present study was to investigate the effect of high-pass filtering on TEOAE obtained from 2-month-old infants as a function of filter cut-off frequency, activity states and pass/fail status of infants. Two experiments were performed. In Experiment 1, 100 2-month-old infants (200 ears) in five activity states (asleep, awake but peaceful, sucking a pacifier, feeding, restless) were tested by use of TEOAE technology. Five different filter conditions were applied to the TEOAE responses post hoc. The filter conditions were set at 781 Hz (default setting), 1.0, 1.2, 1.4 and 1.6 kHz. Results from this experiment showed that TEOAE parameters such as whole-wave reproducibility (WR) and signal-to-noise ratio (SNR) at 0.8 kHz and 1.6 kHz, changed as a function of the cut-off frequency. The findings suggest that the 1.6 kHz and 1.2 kHz filter conditions are optimal for WR and SNR pass/fail criteria, respectively. Although all infant recordings appeared to benefit from the filtering, infants in the noisy states seemed to benefit the most. In Experiment 2, the high-pass filtering technique was applied to 23 infants (35 ears) who apparently failed the TEOAE tests on initial screening but were subsequently awarded a pass status based on the results from a follow-up auditory brainstem response (ABR) assessment. The findings showed a significant decrease in noise contamination of the TEOAE with a corresponding significant increase in WR. With high-pass filtering at 1.6 kHz, 21/35 ears could be reclassified into the pass category.

Outcomes of transient evoked otoacoustic emission testing in 6-year-old school children: a comparison with pure tone screening and tympanometry

OBJECTIVES

(1) To establish test performance measures for Transient Evoked Otoacoustic Emission testing of 6-year-old children in a school setting; (2) To investigate whether Transient Evoked Otoacoustic Emission testing provides a more accurate and effective alternative to a pure tone screening plus tympanometry protocol.

METHODS

Pure tone screening, tympanometry and transient evoked otoacoustic emission data were collected from 940 subjects (1880 ears), with a mean age of 6.2 years. Subjects were tested in non-sound-treated rooms within 22 schools. Receiver operating characteristics curves along with specificity, sensitivity, accuracy and efficiency values were determined for a variety of transient evoked otoacoustic emission/pure tone screening/tympanometry comparisons.

RESULTS

The Transient Evoked Otoacoustic Emission failure rate for the group was 20.3%. The failure rate for pure tone screening was found to be 8.9%, whilst 18.6% of subjects failed a protocol consisting of combined pure tone screening and tympanometry results. In essence, findings from the comparison of overall Transient Evoked Otoacoustic Emission pass/fail with overall pure tone screening pass/fail suggested that use of a modified Rhode Island Hearing Assessment Project criterion would result in a very high probability that a child with a pass result has normal hearing (true negative). However, the hit rate was only moderate. Selection of a signal-to-noise ratio (SNR) criterion set at > or =1 dB appeared to provide the best test performance measures for the range of SNR values investigated. Test performance measures generally declined when tympanometry results were included, with the exception of lower false alarm rates and higher positive predictive values. The exclusion of low frequency data from the Transient Evoked Otoacoustic Emission SNR versus pure tone screening analysis resulted in improved performance measures.

CONCLUSIONS

The present study poses several implications for the clinical implementation of Transient Evoked Otoacoustic Emission screening for entry level school children. Transient Evoked Otoacoustic Emission pass/fail criteria will require revision. The findings of the current investigation offer support to the possible replacement of pure tone screening with Transient Evoked Otoacoustic Emission testing for 6-year-old children. However, they do not suggest the replacement of the pure tone screening plus tympanometry battery.

Test-retest reliability of tone-burst-evoked otoacoustic emissions

In this study, the short- and long-term test-retest reliabilities of tone-burst-evoked otoacoustic emissions (TBOAEs) with 12 different tone-burst stimuli (4 frequencies [1, 1.5, 2 and 3 kHz] at 3 stimulus levels [approximately 76, approximately 67 and approximately 55 dB pcSPL]) were examined in 30 normal hearing subjects. Click-evoked and spontaneous OAEs were recorded in parallel with TBOAEs to facilitate cross-comparisons and the generalization of results. Findings for click-evoked and spontaneous OAEs were comparable with most literature data. High reliability for TBOAEs was established for high and mid stimulus levels at all frequencies tested with reference to test-retest prevalence rate, test retest occurrence, intra-subject test retest difference and correlation coefficient. Derived half-octave band analysis at the frequency corresponding to the stimulus was found to reflect real TBOAE performance more reliably than broadband analysis. No significant difference between short- and long-term reliabilities was noted from all results. Similar test-retest reliabilities for high-level TBOAEs and click-evoked OAEs was obtained, suggesting that TBOAEs could potentially contribute to clinical assessment.

Over-the-counter hearing aids: electroacoustic characteristics and possible target client groups

Over-the-counter hearing aids (OTCs) are those directly purchased from retail outlets, without the benefit of prior professional hearing health care. They are particularly common in developing countries. This study examined the amplification characteristics of a selected sample of OTCs to determine if any target client group or groups were suitable for the OTCs. The electroacoustical performance of 10 OTCs was measured. The measurements included saturated sound pressure level curve, high-frequency average full-on gain, frequency response, total harmonic distortion, equivalent input noise level, and input-output curve. The full-on gain curve of each hearing aid was used to estimate the hypothetical hearing loss of target clients for each aid as it would be calculated by four hearing aid prescription formulae. Real-ear probe tube measurements were also performed on 10 adult subjects to determine the amplification that could be achieved by the OTCs before audible feedback occurred. The OTC hearing aids were not able to meet the prescription gain requirements of the majority of elderly clients who usually purchased them.

Measuring the understanding of sentences by hearing-impaired children: comparison with connected discourse ratings

Measuring the understanding of connected speech by hearing-impaired children is desirable if an appropriate rehabilitative or special educational program is to be implemented or monitored. This study was undertaken to explore the potential of a Cantonese version of the Helen sentence test as a measure of understanding connected speech by a group of 54 mildly to profoundly hearing-impaired children, and to compare the results from this sentence test with those achieved by the same children on a connected discourse test. The effects of two different hearing aid frequency responses and two noise conditions on the results from both tests were also examined. Findings from the present study revealed that the Helen sentence test could be successfully adapted for use with Cantonese-speaking hearing-impaired children in Hong Kong. When compared to the connected discourse test, the modified Helen test produced significantly higher scores and was more sensitive to changes in noise level, especially for the severely and profoundly hearing-impaired children.

Otoacoustic emission findings in Rett syndrome

Rett syndrome is a neurologic disorder affecting mainly females after a seemingly normal 6 to 18 months of life. The resulting developmental disabilities include apparent dementia and loss of acquired language, social skills, and purposeful hand use. The present investigation assessed 10 individuals with Rett syndrome and a control group matched for age and sex. The present study aimed to determine the clinical feasibility of obtaining otoacoustic emissions (OAEs) from the Rett syndrome group and to compare the characteristics of the transient evoked and distortion-product OAEs obtained from the two subject groups. Results indicated that OAE evaluation is a clinically feasible method of assessing individuals with Rett syndrome. The Rett syndrome group had less robust OAEs, especially in the higher frequencies, when compared to the control group. Seven of the Rett syndrome group were identified as having reduced or absent OAEs in at least one ear. These findings suggest a need for hearing screening at an early age and monitoring of hearing on a regular basis.

Transient evoked otoacoustic emissions in two-month-old infants: a normative study

Researchers have recently reported the effects of age, sex, ear asymmetry, and subject's activity status on transient evoked otoacoustic emissions (TEOAEs). The present study aimed to expand upon such reports by describing the characteristics of TEOAE spectra obtained from a cohort of 607 two-month-old infants in community child health clinics. Results indicated significant sex, ear and activity state effects on the signal:noise ratio, response, whole wave and band reproducibility values. These findings suggest the need for TEOAE normative data to be expressed as a function of sex, ear, and activity state of infants. These characteristics of TEOAE spectra may shape future investigations into appropriate pass fail criteria for two-month-old infants.

Otoacoustic emission criteria for neonatal hearing screening

Transient evoked otoacoustic emission measures are gaining acceptance as a technique in new-born hearing screening. At present a wide variety of pass-fail screening criteria are used in otoacoustic emission screening programs. In a study of 100 special care neonates and 35 well, full term babies, a number of screening criteria were examined for sensitivity and specificity characteristics when compared to a standard auditory brainstem response protocol. Results indicate that, for normal and special care neonates with a gestational age at test of 38-41 weeks, high sensitivity ( > 80%) could be obtained when a pass-fail criterion involving analysis of emission reproducibility, or emission reproducibility and emission response level, was set. Sensitivity was reduced for special care neonates who fell outside this age range. Specificity was found to be relatively low overall (always < 65%) and may relate to clinical factors in special care neonates not investigated in this study.

Effects of background noise on click-evoked otoacoustic emissions

OBJECTIVE

To investigate the effect of increased levels of background noise on click-evoked otoacoustic emission (CEOAE) recordings and to compare the effectiveness of the default CEOAE program with the QuickScreen CEOAE program in increased levels of noise, using an Otodynamics ILO88 recording device.

DESIGN

The right ears of 40 young adult women with normal hearing were assessed using CEOAEs under four different noise conditions and with two different methods of data collection. The noise conditions were in quiet, 50 dB A, 55 dB A, and 60 dB A of white noise. Data were collected at each noise level in the default mode and also using the ILO88 QuickScreen program.

RESULTS

There was a significant change in a number of important CEOAE output parameters with increased noise. In the default mode, mean whole wave reproducibility was 89.2% in quiet but declined to 85% with 50 dB A of white noise, 65% at 55 dB A and 20% at 60 dB A. The QuickScreen program proved more robust to the effects of noise than the default. In that mode, mean whole wave reproducibility was 91.7% in quiet, 92.5% with 50 dB A of white noise, 82.5% at 55 dB A and 45% at 60 dB A.

CONCLUSIONS

The findings of the study indicate ambient noise levels for accurate CEOAE recording should not exceed 50 to 55 dB A of noise and alternatives to the default program should be considered in non-sound-treated situations.

Feasibility of community-based hearing screening using transient evoked otoacoustic emissions

This study investigated the feasibility of obtaining transient evoked otoacoustic emissions for hearing screening purposes from infants and children at seven child health clinics. Factors affecting the outcomes of the community hearing screening program were examined. The subject group comprised 2305 children aged two weeks to 11 y 11 mon. Many children were attending the clinics for initial immunisation at two months of age. While there were no exclusion criteria for the 1305 young infants tested who were in this category, all other children were screened only upon receipt of a referral from clinic nurses. Results indicated that 182 children (7.9%) did not complete the screening for both ears within the time constraint (usually 15 min) of a child health clinic visit. Three hundred and sixty-two children (15.7%) failed the first screening. Of the 226 children who returned for a second screening test, separated from the first by at least two weeks, 121 children failed. With parents' consent, 107 children (4.6% of all participants) were referred for diagnostic or medical assessment. Subsequently, 77 out of 94 children who received audiological or medical assessment were found to have some degree of hearing impairment. The majority of positive screening results were associated with middle ear disorder. The results suggest that TEOAE screening has potential as a technique in the community health setting but improvements in instrumentation are required to reduce 'could not test' cases and to separate probable conductive hearing loss from cases likely to have other disorders.

Infant hearing screening: a comparison of two techniques

Hearing screening programs for Australian children are known to have poor coverage in many areas. In addition, only a minority of children are screened for hearing loss before 2 years of age. However, early detection of hearing loss and early treatment are generally considered very important to successful rehabilitation outcomes. Traditional methods of screening infants have limitations with their accuracy in detecting children with hearing loss. This study compared the results obtained with a traditional questionnaire approach to screening and a newer objective technique involving otoacoustic emission measures. Poor correlation was found between pass rates for the two techniques, suggesting that the questionnaire approach is not an accurate screening method for detecting infant hearing loss. With further development, otoacoustic emission testing holds promise as an objective alternative hearing screening procedure.

Childhood hearing loss in sub-Saharan Africa: a review and recommendations

Nearly 10% of the world's population lives in sub-Saharan Africa, a region comprised of many countries with least developed nation status. The region has a predominantly young population and many children in the region are at risk of pathologies associated with hearing loss. Despite the constraints associated with low socioeconomic levels, a number of valuable studies have been carried out into the prevalence and etiology of childhood hearing loss in the sub-Saharan region. A review of the published literature related to childhood hearing loss in sub-Saharan Africa is presented and recommendations made on possible future research directions that could assist hearing loss prevention and management.

Transient evoked otoacoustic emissions in infants: effects of gender, ear asymmetry and activity status

This study examined the effects of gender, ear asymmetry and activity status of infants on various measures of transient evoked otoacoustic emission (TEOAE), including signal-to-noise ratio (SNR) and reproducibility of emissions, using TEOAE as a mass screening procedure in a community health setting. Five hundred and sixty-eight infants were screened for hearing at two months of age, before immunization. The ILO88 Otodynamic Analyzer Quickscreen program was used for all testing with pass/fail criteria similar to those used in the Rhode Island hearing assessment project. The results indicated a significant difference in SNR across sex, with females showing a higher mean SNR. The right ear was found to have higher values in 'reproducibility' and 'response level' than the left ear. A significant difference in SNR across activity states was also evident. Implications from these findings, as applied to community-based screening programs, are discussed.

Internalizing and externalizing characteristics of sexually and/or physically abused children

This study evaluates the behavioral consequences of childhood abuse (sexual, physical, or both), with particular focus on prevalence of posttraumatic stress disorder (PTSD). Three abuse type groups and nonabused controls were contrasted on behavioral rating scales and on structured psychiatric interview data. The participants (109 abused children and 16 normal control children) were recruited from Arkansas Children's Hospital and local agencies for abused children. As expected, proportionately more females than males were sexually abused. Overall, males were rated as more disturbed than females. Type of abuse did not consistently influence behavioral ratings. Externalizing scores were significantly higher than internalizing scores in all abused groups. PTSD was diagnosed in 50% of the abused children, with a higher rate for boys who had been sexually abused as opposed to physically abused only (58% versus 13%). The most frequent comorbid condition with PTSD was Separation Anxiety. Sexually abused boys were hospitalized for psychiatric treatment at a higher rate than were other abused children.

Hearing loss in western Samoan children

In an effort to help determine the current status and needs of hearing impaired children in Western Samoa, the Commonwealth Society for the Deaf sent a team of three professionals to this Pacific island nation in 1991. Initial information on known children with severe and profound hearing loss was gathered and a small prevalence survey of urban school children's ear health was conducted. No previously published information was available for this population. Results are presented and related to data from other areas of the Pacific. Hearing health care implications of the survey team's findings are discussed.

Hearing screening in Australian aboriginal university students

Many indigenous peoples have been found to show an increased prevalence of both middle ear disorder and associated conductive hearing loss. Hearing loss may cause educational disadvantage during school years. For many indigenous populations in developed countries there are now increasing opportunities to participate in established formal education. This has led to greater numbers of indigenous students in post-secondary education. This study examined the results of a three-year hearing health programme for Australian Aboriginal students entering university studies. Prevalence rates were compared with those of urban Aboriginal adult non-students and non-indigenous populations. It was found that 15.5% of indigenous university students had a unilateral or bilateral hearing loss. Recommended screening procedures and methods to enhance classroom listening for indigenous hearing impaired students were suggested.

Performance of assistive listening devices using insertion gain measures

The electroacoustic performance characteristics of seven assistive listening devices (ALDs), that did not need to be coupled with a hearing aid, were measured using real ear insertion gain. The ALDs, which included TV listening systems and personal amplification systems, were measured on ten subjects. Electroacoustic performance of the ALDs varied although there were similarities for different types of devices. Frequency responses were either basically flat or had an emphasis in the low or mid-frequency region. The majority of devices provided negligible amplification when set at or below half volume. Total harmonic distortion was 10% or less for most ALDs. Overall, insertion gain measures were found to be of value in evaluating the effectiveness of this type of amplification device.

External ear resonance as a screening technique in children with otitis media with effusion

External ear resonance can be quickly and accurately measured using real ear insertion gain equipment. It has been previously shown that external ear resonance characteristics are often altered by the presence of middle ear fluid. The external ear resonance characteristics of 84 children with a history of chronic middle ear disorder were determined. Results were compared to other audiological data and otological findings recorded during surgery. External ear resonance peak amplitude was significantly correlated with the presence or absence of middle ear fluid. It was found that peak amplitude of > or = 24 dB was associated with only 15% of dry ears and peak amplitude of < or = 22 dB associated with 79% of ears without fluid. The use of external ear resonance measures as a potential screening procedure is discussed.

Test-retest variability using the Liverpool screening audiometer in a field environment

The Liverpool Field Audiometer (LFA) has been developed as a simple, hand-held device for screening audiometry in developing countries. The variability in the outcome of screening using the LFA was studied with 275 primary schoolchildren in five Brisbane schools. A 30 dB HL screening level was used. The device was found to give low test-retest outcome variability at the test frequencies 1000 Hz, 2000 Hz and 4000 Hz. However, variability was high at 500 Hz and caution should be exercised when data at this frequency are obtained. Possible reasons for this low-frequency variability are suggested.

Clinical reliability of insertion gain measurements with assistive listening devices

Real ear insertion gain was measured in 14 persons fitted with a variety of common assistive listening devices. Measurements were made in a quiet, but not soundproofed, clinical environment. The reliability of such insertion gain measures was studied, both for short-term and long-term test-retest conditions. The results indicated that insertion gain measurement of assistive listening devices can be performed as a routine clinical procedure. Intrasubject standard deviations were comparable in most cases to those clinically obtained using hearing aids with custom ear moulds.

Sequelae of epidemic meningococcal meningitis in Africa

Audiological and other long-term neurological sequelae were determined in 157 cases and their controls matched for age, sex and village 6 to 12 months after an epidemic of group A meningococcal meningitis in rural West Africa. 19 cases (12.1%) and 3 controls (1.9%) had moderate or severe neurological sequelae of any type (P less than 0.001); 6 cases (3.9%) and no controls had severe or profound sensorineural hearing loss (P = 0.03). There was no difference in conductive hearing loss between cases and controls. Other cranial nerve sequelae (except visual defects) and generalized neurological and motor and co-ordination sequelae were also significantly increased in cases. Sensorineural hearing loss and other cranial nerve sequelae occurred significantly more frequently in males than in females, and co-ordination sequelae more frequently in cases aged 10 years or more than in younger cases. Sensorineural hearing loss and loss of visual acuity were found significantly more frequently in cases whose treatment was delayed for 4 d or more, compared with those who received treatment sooner.

A study of deafness in West Africa: the Gambian Hearing Health Project

Research was carried out on various aspects of deafness in a West African population. A national survey of childhood deafness was completed to discover the incidence and causes of severe to profound hearing loss in The Republic of the Gambia. A large school screening campaign was conducted to determine the prevalence of middle ear disease in Gambian children. Smaller studies concerned the hearing loss among post-meningitis patients; the disease pattern of audiology clinic patients in both urban and rural areas; the degree of hearing loss associated with otitis media and the rubella serology of a group of Gambian women and children. It was found that meningitis was a major identifiable disease causing deafness. Rubella and measles, often causes of deafness in other tropical countries, did not seem to be of such importance in The Gambia. Familial factors also accounted for little of the childhood deafness as far as it was possible to tell. Chronic middle ear infections could give rise to considerable hearing loss but rarely led to the dangerous complications often seen in other tropical communities. Effective medical and audiological services for the deaf are difficult to implement in developing countries. A primarily preventive approach may prove to be the most rational way of helping the deaf in The Gambia.

Isolation and characterization of a bacteriophage factor that confers competence for genetic transformation to an exfoliative toxin-producing strain of Staphylococcus aureus

Competence for genetic transformation in an exfoliative toxin-producing strain of Staphylococcus aureus was shown to be dependent on a virion factor that was isolated from a crude bacteriophage 80 alpha lysate. This competence-conferring factor was completely separated from infectious virus particles after either centrifugation through a neutral sucrose velocity gradient or fractionation on a Sepharose 2B gel. Since the competence-conferring factor tends to aggregate, optimal separation was obtained after treatment of the phage factor with the detergent Nonidet P-40. The competence-conferring factor had a molecular weight between 3 X 10(6) and 20 X 10(6) and an approximate sedimentation coefficient of 252. The factor was neutralized after interaction with antiserum prepared against isolated infectious 80 alpha virions. Electron microscopy of transforming cells that were exposed to isolated competence-conferring factor revealed a significant number of abnormally long and aggregated phage tail-like structures attached to the surface of recipient cells. This phenomenon was only observed in the presence of donor DNA, indicating that a phage tail-DNA-surface receptor complex might be one of the early steps in DNA-mediated transformation of S. aureus.

The social system of age group swimming: the perceptions of swimmers, parents and coaches

The opinions of swimmers, parents and coaches on the social aspect of age group swimming indicate a unanimity of opinion on the value of this activity in the community. Nevertheless a majority of all subgroups thought some changes in its structure should take place. Principally more "fun" should mark both games and practices, heavy training and competition should be deemphasized while current motivational techniques and learning principles should be learned and observed by coaches.

Pre-retirement life-style and the degree of planning for retirement

The purpose of this study was to examine the relationship between the pre-retirement life-style of adult men, and both the degree of planning for the retirement years and the decision to retire early. Adult males (N = 360) between 55 and 64 years of age were interviewed about their present leisure life-style and the amount of retirement planning they were doing or had done. In order to determine which demographic, attitudinal and social participation variables predict retirement related behavior, Multiple Classification Analysis (MCA) was used. It was found that socioeconomic status, health, involvement in expressive type organizations, job satisfaction and degree of leisure orientation were associated with pre-retirement attitudes toward retirement.

Isolation of Leishmania braziliensis from a wild rodent in Costa Rica

Leishmania braziliensis panamensis has been isolated in culture from one spiny-pocket mouse (Heteromys dermarestianus) out of 43 examined, proving that rodents of this genus can be reservoirs of Leishmania of the braziliensis complex as well as of mexicana in Latin America.