Force Perception Thresholds in Cochlear Implantation Surgery

Kratchman L.B. et al. (2016) Audiology & Neurotology. 21. pp. 244-249

B0003932 Illustration of hands reaching out

Image source: Matthew Herring – Wellcome Images // CC BY-NC-ND 4.0

Tissue trauma is a frequent complication of cochlear implantation (CI) surgery, but the relationship between intracochlear trauma, electrode insertion forces, and surgeons’ ability to perceive these forces is poorly understood.

In this study, we simulated CI surgery using a benchtop apparatus to repeatedly apply small forces to the subjects’ hands while reducing the variability in their hand movements. We used a psychophysical testing procedure to estimate the force perception thresholds of 10 otologic surgeons and found a median threshold of 20.4 mN.

The results suggest that surgeons have the capability to sense at least some insertion forces and are likely to perceive severe trauma such as occurs when the electrode crosses from one scala to the other.

Read the abstract here

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Psychosocial development of 5-year-old children with hearing loss: Risks and protective factors

Wong, C.L. et al. International Journal of Audiology. Published online: 19 Aug 2016

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Objective: The aims of this paper were to report on the global psychosocial functioning of 5-year-old DHH children and examine the risk and protective factors that predict outcomes.

Design: A cross-sectional analysis of data collected from a prospective, population-based longitudinal study.

Study sample: Parents/caregivers of 356 children completed questionnaires on psychosocial development (CDI, SDQ), functional communication (PEACH) and demographic information. Children completed standardized assessments of non-verbal cognitive ability (WNV) and language (PLS-4).

Results: On average, global psychosocial functioning was within the range of typically developing children; however, variability was high and 12% of children had scores that were more than 2 SDs below the norm. Non-verbal cognitive ability, presence of additional disabilities, language and functional communication significantly predicted outcomes. In contrast, type of hearing device, severity of hearing loss and age at intervention did not.

Conclusion: The global psychosocial functioning of this cohort of 5-year-old DHH children fell within the range of typically developing children. The findings suggest that spoken language ability and functional communication skills are vital for healthy psychosocial development.

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Clients’ perspective on quality of audiology care: Development of the Consumer Quality Index (CQI) ‘Audiology Care’ for measuring client experiences

Hendricks, M. et al. International Journal of Audiology . Published online: 17 August 2016

Objective: Clients’ perspective on the quality of audiology care has not been investigated thoroughly. Research has focused primarily on satisfaction with, and limitations of hearing aids. We developed a Consumer Quality Index (CQI) questionnaire ‘Audiology Care’ to systematically assess client experiences with audiology care.

Design: The CQI Audiology Care was developed in three steps: (1) posing open-ended questions through e-mail (n = 14), (2) two small-scale surveys assessing psychometric properties of the questionnaire (n = 188) and importance of quality aspects (n = 118), and (3) a large-scale survey (n = 1793) assessing psychometric properties and discriminatory power of the questionnaire.

Study sample: People with complex hearing impairments and/or balance and communicative disorders who visited an audiology care centre during the past year.

Results: Important quality aspects were translated into seven reliable scales: accommodation and facilities, employees’ conduct and expertise, arrangement of appointments, waiting times, client participation and effectiveness of treatment. Client experiences differed among the participating centres concerning accommodation and facilities, arrangement of appointments, waiting times and client participation.

Conclusion: The CQI Audiology Care is a valid and reliable instrument to assess clients’ experiences with audiology care. Future implementation will reveal whether results can be used to monitor and improve the quality of audiology care.

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

Van der Aerschot, M. et al. International Journal of Audiology. Published online: 17 August 2016

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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.

Read the abstract here

New research into biology of progressive hearing loss

Action on Hearing Loss | Published online: 16 August 2016

New research with funding from UK charity Action on Hearing Loss has led to the discovery of a new biological mechanism involved in the progressive loss of hearing which could lead to new approaches to treating this common form of hearing loss.

It’s known that gradual loss of sound-detecting sensory hair cells within the inner ear is associated with progressive hearing loss, but now researchers from King’s College London, the Wellcome Trust Sanger Institute, and University College London have shown that defects in a structure within the ear called the stria vascularis, can also cause progressive hearing loss.

The stria vascularis is essential for normal hearing and is involved in maintaining the endocochlear potential – a difference in charged molecules between compartments of the inner ear which acts like a battery to power the transmission of sound signals from the ear to the brain.

Researchers made the discovery while investigating why mice with a specific mutation in a gene called S1pr2 have a progressive loss of hearing, and found degeneration of the stria vascularis and a low endocochlear potential in these mice correlated with their loss of hearing. Significantly, the gene in humans is also associated with changes in people’s ability to hear – making this discovery relevant to progressive hearing loss in the human population.

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Knowledge and attitude of parents/caregivers towards hearing loss and screening in newborns – a systematic review

Ravi, R. et al. International Journal of Audiology | Published online: 15 August 2016

Objective: The parents/caregivers of a newborn play a pivotal role in the process of hearing screening and intervention. The decisions taken by them depend on their knowledge and attitude. The purpose of this study was to review the literature systematically on knowledge and attitude of parents/caregivers towards infant hearing loss and newborn hearing screening.

Design: A systematic search was conducted using electronic databases for the periods from 1990 to March 2016. Two authors scrutinized the studies and extracted the data based on predetermined criteria.

Study sample: Ten studies.

Results: Ear discharge was correctly identified as a risk factor for hearing loss along with measles, drugs/medication, family history, congenital causes and noise exposure. The studies revealed mixed results for knowledge about newborn hearing screening. Overall, the parents/caregivers showed positive attitudes towards hearing screening and intervention options. However, due to heterogeneity in the studies, it’s hard to derive a conclusion.

Conclusions: The present review sheds light on the common areas of misconception among parents/caregivers about risk factors of infant hearing loss and newborn hearing screening. The review also draws attention to the need to have more studies exploring this knowledge and attitude of parents/caregivers among diverse populations.

Read the abstract here

Hearing test may identify autism risk

ScienceDaily. Published online: 25 July 2016

jigsaw-305576_960_720Researchers have identified an inner ear deficiency in children with Autism that may impact their ability to recognize speech. The findings, which were published in the journal Autism Research, could ultimately be used as a way to identify children at risk for the disorder at an early age.

One of the challenges to early detection of ASD is to find ways to identify children at risk for the disorder sooner and in children with speech delays. Some of the earliest and consistent signs of ASD involve auditory communication, however, most tests rely on speech, and are often ineffective in children who are very young or who have communication delays.

In the new study, researchers used a technique that measures what are called otoacoustic emissions. The test is akin to the screening that many newborns must undergo before leaving the hospital to check for hearing problems. Using miniature speaker/microphone earplugs, the researchers were able to measure hearing deficiencies by listening for signs that the ear is having difficulty processing sounds. Specifically, the device’s highly sensitive microphone can detect minute sound emission made by inner ear outer hair cells in response to certain tones or clicking sounds. If these cells are not functioning properly, the device fails to detect an emission which indicates that inner ear — or cochlear — function is impaired.

The researchers tested the hearing of children between the ages of 6 and 17, roughly half of whom have been diagnosed with ASD. They found that the children with ASD had hearing difficultly in a specific frequency (1-2 kHz) that is important for processing speech. They also found a correlation between the degree of cochlear impairment and the severity of ASD symptoms.

Read the full commentary here

Read the original research abstract here