bioRxiv Science⌕ Search

bioRxiv · 10.1101/2020.09.03.281717

Effects of age and hearing loss on perceptual and physiological measures of temporal envelope processing and spatial release from speech-on-speech masking

Abstract

Older adults often experience difficulties understanding speech in adverse listening conditions. These difficulties are partially attributed to auditory temporal-processing deficits associated with aging even in the absence of hearing loss. The aim of this study was to assess effects of age and hearing loss on temporal envelope processing and speech-on-speech masking. Listeners with normal and near-normal hearing across a wide age range (20 to 66 years) were tested using a series of psychophysical (amplitude-modulation detection, gap detection, and interaural-envelope-phase discrimination), physiological (electroencephalographic envelope-following responses), speech perception (spatial release from masking), and cognitive (processing speed) measures. Results showed that: (i) psychophysical measures of monaural and binaural envelope processing and neural measures of envelope processing are not affected by aging after accounting for audiometric hearing loss, (ii) behavioral gap-detection thresholds decline with age, (iii) aging results in a reduction of spatial release from masking, even as speech intensity is amplified in the region of hearing loss, (iv) aging is associated with poorer measures of cognitive function. Although age significantly contributed to a decline in spatial release from speech-on-speech masking, individual differences in envelope processing and in scores from nonauditory cognitive tests used in this study were not significant predictors of speech performance. HighlightsO_LIAge per se does not affect psychophysical and physiological measures of monaural amplitude-modulation processing. C_LIO_LIAge does not affect the ability to detect interaural disparities in envelope timing between the ears. C_LIO_LIGap detection thresholds degrades with age even after hearing thresholds are statistically accounted for. C_LIO_LIAge, independent of hearing thresholds, can substantially reduce spatial release from masking. C_LIO_LICognitive ability declines with age. However, such declines do not necessarily cause deficits in spatial release from masking. C_LI

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Patro, C., Kreft, H. A., Wojtczak, M.. 2020-09-04. Effects of age and hearing loss on perceptual and physiological measures of temporal envelope processing and spatial release from speech-on-speech masking. https://doi.org/10.1101/2020.09.03.281717

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Skeletal muscle aging drives sex- and compartment-specific protein insolubility that is modifiable by proteostasis-directed treatments

Protein aggregation and altered protein solubility indicate proteostatic decline, yet their roles in skeletal muscle aging remain poorly understood. We combined light and electron microscopy, quantitative proteomics, and stable-isotope labeling of skeletal muscle to investigate age-associated changes in protein insolubility, and their responses to exercise and rapamycin. Aged muscle accumulated distinct aggresome and amyloid-positive aggregates despite unchanged bulk insoluble protein content. Instead, aging altered the abundance and soluble-insoluble shifts of lower-abundance proteins across cellular components, particularly mitochondrial, nuclear and extracellular matrix proteins, with greater changes in females. These changes were not broadly explained by intrinsic protein aggregation propensity. Exercise and rapamycin partially reversed age-associated changes in abundance and partitioning without increasing protein synthesis. Together, these findings highlight sex- and cellular component-dependent changes in protein insolubility as important, modifiable aspects of skeletal muscle proteostasis, and indicate that proteostatic maintenance may be a more important target than anabolism for muscle aging.

physiology↗

Trunk muscle activity across various trunk-limb coordination patterns in centipede locomotion

Animals coordinate movements of their limbs and flexible bodies, yet how trunk muscle activity changes across locomotor patterns remains unclear. We simultaneously recorded electromyograms from trunk muscles (deep dorsal oblique muscles) and trunk-limb kinematics in two centipede species exhibiting retrograde and direct locomotor waves during swimming and walking. During swimming, trunk muscle activity followed a similar phase relationship with trunk bending in both species despite opposite wave directions and different involvement of limbs, suggesting common active generation of undulation. During fast walking, trunk muscle activity was strongest around the ipsilateral swing phase in the undulatory retrograde-wave gait of Scolopendra mutilans, but weaker and associated with the ipsilateral stance phase despite the nearly straight trunk in the direct-wave gait of Scolopocryptops rubiginosus. Together, our findings suggest that the same trunk muscles serve two contrasting mechanical roles depending on locomotor mode: either generating trunk undulation or actively straightening the trunk against limb-induced deformation.

physiology↗

Quantifying and Visualizing the Invisible Hazard of Infant Rebreathing

BACKGROUND: Rebreathing of expired gases during prone infant sleeping contributes to hypoxic and hypercapnic exposure, even without airway obstruction. We investigated how anatomical, physiological, and environmental factors influence aerodynamic rebreathing. METHODS: A dynamically scaled in vitro model simulated prone nasal breathing corresponding to infants weighing 2 to 5 kg, with nostril diameters of 3.2 to 6.0 mm and breathing frequencies of 25 to 40 breaths/min. Ambient temperature and sleep-surface characteristics were varied. Rebreathing was quantified using tracer measurements, while flow visualization revealed the underlying aerodynamic mechanisms. RESULTS: Rebreathing exceeded 60% despite unobstructed nasal openings. Increasing ambient temperature from 23 to 30 degrees C increased rebreathing by 68 to 77%, while reducing simulated infant mass from 5 to 2 kg increased rebreathing by 39 to 46%. Fibrous surfaces increased rebreathing, particularly near inclined nasal openings. A novel finding was that increasing nostril diameter from 3.2 to 6.0 mm increased rebreathing by up to 50%. Flow visualization revealed vortical structures that retained expired fluid near the nasal openings, facilitating re-inspiration. CONCLUSIONS: Aerodynamic rebreathing depends strongly on simulated infant characteristics and sleeping environments. These findings are consistent with established safe-sleep recommendations and identify nostril diameter, for the first time, as a potentially important anatomical factor warranting clinical investigation.

physiology↗