10.3109/14992027.2016.1172269<br/>Jenni-Marí Potgieter
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Παρασκευή 29 Απριλίου 2016
Development and validation of a smartphone-based digits-in-noise hearing test in South African English.
Development and validation of a smartphone-based digits-in-noise hearing test in South African English.
Int J Audiol. 2016 Apr 28;:1-7
Authors: Potgieter JM, Swanepoel W, Myburgh HC, Hopper TC, Smits C
Abstract
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.
PMID: 27121117 [PubMed - as supplied by publisher]
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Activity-dependent, homeostatic regulation of neurotransmitter release from auditory nerve fibers.
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Activity-dependent, homeostatic regulation of neurotransmitter release from auditory nerve fibers.
Proc Natl Acad Sci U S A. 2015 May 19;112(20):6479-84
Authors: Ngodup T, Goetz JA, McGuire BC, Sun W, Lauer AM, Xu-Friedman MA
Abstract
Information processing in the brain requires reliable synaptic transmission. High reliability at specialized auditory nerve synapses in the cochlear nucleus results from many release sites (N), high probability of neurotransmitter release (Pr), and large quantal size (Q). However, high Pr also causes auditory nerve synapses to depress strongly when activated at normal rates for a prolonged period, which reduces fidelity. We studied how synapses are influenced by prolonged activity by exposing mice to constant, nondamaging noise and found that auditory nerve synapses changed to facilitating, reflecting low Pr. For mice returned to quiet, synapses recovered to normal depression, suggesting that these changes are a homeostatic response to activity. Two additional properties, Q and average excitatory postsynaptic current (EPSC) amplitude, were unaffected by noise rearing, suggesting that the number of release sites (N) must increase to compensate for decreased Pr. These changes in N and Pr were confirmed physiologically using the integration method. Furthermore, consistent with increased N, endbulbs in noise-reared animals had larger VGlut1-positive puncta, larger profiles in electron micrographs, and more release sites per profile. In current-clamp recordings, noise-reared BCs had greater spike fidelity even during high rates of synaptic activity. Thus, auditory nerve synapses regulate excitability through an activity-dependent, homeostatic mechanism, which could have major effects on all downstream processing. Our results also suggest that noise-exposed bushy cells would remain hyperexcitable for a period after returning to normal quiet conditions, which could have perceptual consequences.
PMID: 25944933 [PubMed - indexed for MEDLINE]
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Development and validation of a smartphone-based digits-in-noise hearing test in South African English.
Development and validation of a smartphone-based digits-in-noise hearing test in South African English.
Int J Audiol. 2016 Apr 28;:1-7
Authors: Potgieter JM, Swanepoel W, Myburgh HC, Hopper TC, Smits C
Abstract
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.
PMID: 27121117 [PubMed - as supplied by publisher]
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Development and validation of a smartphone-based digits-in-noise hearing test in South African English
10.3109/14992027.2016.1172269<br/>Jenni-Marí Potgieter
from #Audiology via ola Kala on Inoreader http://ift.tt/248U0sc
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Influence of virtual height exposure on postural reactions to support surface translations
Publication date: June 2016
Source:Gait & Posture, Volume 47
Author(s): Taylor W. Cleworth, Romeo Chua, J. Timothy Inglis, Mark G. Carpenter
As fear of falling is related to the increased likelihood of falls, it is important to understand the effects of threat-related factors (fear, anxiety and confidence) on dynamic postural reactions. Previous studies designed to examine threat effects on dynamic postural reactions have methodological limitations and lack a comprehensive analysis of simultaneous kinetic, kinematic and electromyographical recordings. The current study addressed these limitations by examining postural reactions of 26 healthy young adults to unpredictable anterior–posterior support-surface translations (acceleration=0.6m/s2, constant velocity=0.25m/s, total displacement=0.75m) while standing on a narrow virtual surface at Low (0.4cm) and High (3.2m) virtual heights. Standing at virtual height increased fear and anxiety, and decreased confidence. Prior to perturbations, threat led to increased tonic muscle activity in tibialis anterior, resulting in a higher co-contraction index between lower leg muscles. For backward perturbations, muscle activity in the lower leg and arm, and center of pressure peak displacements, were earlier and larger when standing at virtual height. In addition, arm flexion significantly increased while leg, trunk and center of mass displacements remained unchanged across heights. When controlling for leaning, threat-related factors can influence the neuro-mechanical responses to an unpredictable perturbation, causing specific characteristics of postural reactions to be facilitated in young adults when their balance is threatened.
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Source:Gait & Posture, Volume 47
Author(s): Taylor W. Cleworth, Romeo Chua, J. Timothy Inglis, Mark G. Carpenter
As fear of falling is related to the increased likelihood of falls, it is important to understand the effects of threat-related factors (fear, anxiety and confidence) on dynamic postural reactions. Previous studies designed to examine threat effects on dynamic postural reactions have methodological limitations and lack a comprehensive analysis of simultaneous kinetic, kinematic and electromyographical recordings. The current study addressed these limitations by examining postural reactions of 26 healthy young adults to unpredictable anterior–posterior support-surface translations (acceleration=0.6m/s2, constant velocity=0.25m/s, total displacement=0.75m) while standing on a narrow virtual surface at Low (0.4cm) and High (3.2m) virtual heights. Standing at virtual height increased fear and anxiety, and decreased confidence. Prior to perturbations, threat led to increased tonic muscle activity in tibialis anterior, resulting in a higher co-contraction index between lower leg muscles. For backward perturbations, muscle activity in the lower leg and arm, and center of pressure peak displacements, were earlier and larger when standing at virtual height. In addition, arm flexion significantly increased while leg, trunk and center of mass displacements remained unchanged across heights. When controlling for leaning, threat-related factors can influence the neuro-mechanical responses to an unpredictable perturbation, causing specific characteristics of postural reactions to be facilitated in young adults when their balance is threatened.
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