CONTENT VALIDITY OF SELECTED ITEMS FROM THE SPEECH, SPATIAL AND QUALITIES OF HEARING SCALE FOR PARENTS (SSQ-P) AS MEASURED BY A SURVEY OF EXPERT OPINION

Introduction: The purpose of this small-scale study was to assess the content validity of a modified subset of ten items from the Speech, Spatial and Qualities of Hearing Scale for Parents (SSQ-P) via a survey of expert opinion. Material and methods: An online survey was used to obtain opinions from 10 experts in the field of children’s hearing and hearing assessment. Experts were asked to rate the relevance and representativeness of each SSQ-P item to deaf and hard of hearing children aged 5 years and over. Content validity was assessed by the item content validity index (ICVI), with excellent content validity identified as an ICVI above 0.8. Experts were also asked to suggest where they felt the wording of items could be improved. Results: For all items, ICVIs > 0.8 were obtained for both relevance and representativeness, indicating excellent content validity. Some minor rewording suggestions were made. Conclusions: The 10 items tested are candidates for inclusion in an abbreviated version of SSQ-P. Some minor rewording of items may be required, along with assessment of internal consistency and test–retest stability

Evidence for an Association Between Hearing Impairment and Disrupted Sleep: Scoping Review

Purpose: Hearing impairment (HI) is the most common sensory impairment and may negatively impact sleep through reduced auditory input. Factors associated with HI, such as anxiety regarding communication in daily life, may also adversely impact an individual’s sleep. Here, research on the relationship between HI and sleep disruption was catalogued using scoping review methodology. Methods: A systematic strategy was employed to search various electronic databases. This review is reported according to Preferred Reporting Items for Systematic Review and Meta-analysis Scoping Review Extension (PRISMA-ScR). Results: Sixteen records met inclusion criteria. Studies have investigated sleep in HI as a primary aim in noise exposed workers or large surveys in older participants. Experimental and quasi-experimental studies report alterations to sleep architecture of potential neuroplastic origins. Studies reporting sleep as a secondary aim generally report poorer in sleep in HI participants. Conclusions: This scoping review has catalogued evidence that altered or negatively impacted sleep may be associated with HI. Potential confounding factors, mechanisms, and considerations for future research are discussed

Comparison of high versus low frequency cerebral physiology for cerebrovascular reactivity assessment in traumatic brain injury: a multi-center pilot study

Current accepted cerebrovascular reactivity indices suffer from the need of high frequency data capture and export for post-acquisition processing. The role for minute-by-minute data in cerebrovascular reactivity monitoring remains uncertain. The goal was to explore the statistical time-series relationships between intra-cranial pressure (ICP), mean arterial pressure (MAP) and pressure reactivity index (PRx) using both 10-s and minute data update frequency in TBI. Prospective data from 31 patients from 3 centers with moderate/severe TBI and high-frequency archived physiology were reviewed. Both 10-s by 10-s and minute-by-minute mean values were derived for ICP and MAP for each patient. Similarly, PRx was derived using 30 consecutive 10-s data points, updated every minute. While long-PRx (L-PRx) was derived via similar methodology using minute-by-minute data, with L-PRx derived using various window lengths (5, 10, 20, 30, 40, and 60 min; denoted L-PRx_5, etc.). Time-series autoregressive integrative moving average (ARIMA) and vector autoregressive integrative moving average (VARIMA) models were created to analyze the relationship of these parameters over time. ARIMA modelling, Granger causality testing and VARIMA impulse response function (IRF) plotting demonstrated that similar information is carried in minute mean ICP and MAP data, compared to 10-s mean slow-wave ICP and MAP data. Shorter window L-PRx variants, such as L-PRx_5, appear to have a similar ARIMA structure, have a linear association with PRx and display moderate-to-strong correlations (r ~ 0.700, p Peer reviewe

Simultaneous suppression of tone burst-evoked otoacoustic emissions: two and three-tone burst combinations

The present work aims to produce rhamnolipid from waste cooking oil (WCO) using a newly isolated bacterium named Pseudomonas SWP-4. SWP-4 was a high-yield strain that could accumulate rhamnolipid steadily even in decline phase and gave a maximum rhamnolipid yield of 13.93 g/L and WCO utilization percent around 88%. The critical micelle concentration of the produced rhamnolipid was only 27 mg/L and its emulsification index against n-hexadecane reached around 59%. Moreover, it reduced the surface tension of water from 71.8 mN/m to 24.1 mN/m and the interfacial tension against n-hexadecane from 29.4 mN/m to 0.9 mN/m. Results of biosurfactant stability show the rhamnolipid was effective when the salinity was lower than 8% and pH value ranged from 4 to 10, and it was quite thermostable based on thermal gravity analysis. Furthermore, it maintained high surface activity even after incubation under extreme conditions i.e. pH of 4.0, salinity of 8% and temperature of 80°C for half a month. Based on free fatty acids metabolism analysis, Pseudomonas SWP-4 consumed palmitic acid, oleic acid and linoleic acid chiefly. All these characteristics demonstrate bioconversion and biodegradation of WCO by Pseudomonas SWP-4 is a promising and commercial way of rhamnolipid production and waste treatment

Changes in sound-source localization for children with bilateral severe to profound hearing loss following simultaneous bilateral cochlear implantation

Background: Sound localization is a valuable skill that children can develop to some extent via bilateral cochlear implants (biCIs). However, little is known regarding the change that can be expected in sound-source localization accuracy (SLA) pre- and post-biCI for children with bilateral, severe-to-profound hearing impairment who spent their early years listening via bilateral hearing aids (biHAs). This study therefore aimed to prospectively assess SLA in a group of children before, and at one year after, receiving simultaneous biCIs. Methods: Ten children aged 5–18 years were tested. SLA was assessed using loudspeakers positioned at −60, −30, 0, +30, and +60 degrees azimuth. Root mean square (RMS) errors and percentage correct scores were calculated. Changes in SLA were analysed via paired t-tests and potential relationships between hearing threshold levels (HTLs) and SLA via correlation analyses. Response distributions via biHAs and biCIs were examined via scatterplots. Results: The mean within-subject changes in SLA were a significant improvement in RMS error of 11.9° (p < 0.05) and in per cent correct by 21.5% (p < 0.05). Scatterplots demonstrated a trend towards better localization of sounds from 0° azimuth via biCIs compared to via biHAs. No significant associations were found between any measures of SLA and HTLs. Conclusions: The findings of the present study demonstrate that simultaneous biCIs lead to improved sound localization in children with bilateral, severe to profound sensorineural hearing loss who previously used biHAs. SLA via biHAs or biCIs could not be predicted from children’s audiograms, and therefore should be measured directly

A mechanism for simultaneous suppression of tone burst-evoked otoacoustic emissions

Tone burst-evoked otoacoustic emission (TBOAE) components in response to a 1 kHz tone burst are suppressed by the simultaneous presence of tone bursts at higher frequencies. To date, the underlying cause of this “simultaneous suppression” of TBOAEs is unclear. This paper describes a potential mechanism based on local nonlinear interactions between basilar membrane (BM) travelling waves, and tests the extent to which it is able to account for this specific suppression phenomenon. A simple mathematical model based on local nonlinear interactions was developed, and its predictions for a range of tone burst pairs were compared to corresponding TBOAE suppression data recorded from fourteen normally hearing human ears at a level of 60 dB p.e. SPL. Model predictions and mean TBOAE suppression data showed close agreement for all pairs of tone bursts. These results suggest that simultaneous suppression of TBOAEs can be explained solely in terms of the local nonlinear interaction-based mechanism. However, the involvement of other mechanisms, involving components generated at places basal to their characteristic place along the BM, cannot be excluded.<br/

Simultaneous suppression of tone burst-evoked otoacoustic emissions - effect of level and presentation paradigm

There is conflict in the literature over whether individual frequency components of a transient-evoked otoacoustic emission (TEOAE) are generated within relatively independent “channels” along the basilar membrane (BM), or whether each component may be generated by widespread areas of the BM. Two previous studies on TEOAE suppression are consistent with generation within largely independent channels, but with a degree of interaction between nearby channels. However, both these studies reported significant suppression only at high stimulus levels, at which the “nonlinear” presentation paradigm was used. The present study clarifies the separate influences of stimulus level and presentation paradigm on this type of suppression. TEOAEs were recorded using stimulus tone bursts at 1, 2 and 3 kHz and a complex stimulus consisting of a digital addition of the three tone bursts, over a range of stimulus levels and both “linear” and “nonlinear” presentation paradigms. Responses to the individual tone bursts were combined offline and compared with responses to the complex stimuli. Results clearly demonstrate that TEOAE suppression under these conditions is dependent upon stimulus level, and not upon presentation paradigm. It is further argued that the data support the “local” rather than “widespread” model of TEOAE generation, subject to nonlinear interactions between nearby generation channels. Abbreviations: BM, basilar membrane; OAE, otoacoustic emission; TEOAE, Transient-evoked otoacoustic emissions; I–O, Input–output; 2TS two-tone suppression