The salary of the first author was funded by The Ear Trust (Registered Charity No. 1000929). No financial contributors to The Ear Trust were involved with the study design, data collection, analysis and interpretation of data, report writing nor the decision to submit the article for publication.

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 interactionbased mechanism. However, the involvement of other mechanisms, involving components generated at places basal to their characteristic place along the BM, cannot be excluded.

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 tonebursts at 1, 2 and 3 kHz and a complex stimulus consisting of a digital addition of the three tonebursts, over a range of stimulus levels and both "linear" and "nonlinear" presentation paradigms. Responses to the individual tonebursts 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.Killan EC Simultaneous Suppression of TBOAEs 3

24Objective: To document changes in speech reception thresholds (SRTs) and spatial release 25 from masking (SRM) for sequentially implanted children at two and four years after they 26 received their second cochlear implant (CI 2 ). SRM. SRTs in quiet improved more for CI 2 than for the first implant (CI 1 ). SRTs in noise and 34SRM improved more when noise was presented closest to CI 1 than when closest to CI 2 . 35Performance became more symmetrical over time.

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. Method A systematic strategy was employed to search various electronic databases. This review is reported according to the Preferred Reporting Items for Systematic Review and Meta-Analyses Scoping Review Extension. 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 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. Supplemental Material https://doi.org/10.23641/asha.9968369