Onset Asynchrony: Cue to Aid Dichotic Vowel Segregation in Listeners With Normal Hearing and Hearing Loss.

PURPOSE: The effect of onset asynchrony on dichotic vowel segregation and identification in normal-hearing (NH) and hearing-impaired (HI) listeners was examined. We hypothesized that fusion would decrease and identification performance would improve with increasing onset asynchrony. Additionally, we hypothesized that HI listeners would gain more benefit from onset asynchrony. METHOD: A total of 18 adult subjects (nine NH, nine HI) participated. Testing included dichotic presentation of synthetic vowels, /i/, /u/, /a/, and /ae/. Vowel pairs were presented with the same or different fundamental frequency (f o; f o = 106.9, 151.2, or 201.8 Hz) across the two ears and one onset asynchrony of 0, 1, 2, 4, 10, or 20 ms throughout a block (one block = 80 runs). Subjects identified the one or two vowels that they perceived on a touchscreen. Subjects were not informed that two vowels were always presented or that there was onset asynchrony. RESULTS: The effect of onset asynchrony on fusion and vowel identification was greatest in both groups when Δf o = 0 Hz. Mean fusion scores across increasing onset asynchronies differed significantly between the two groups with HI listeners exhibiting less fusion across pooled Δf o. There was no significant difference with identification performance. CONCLUSIONS: As onset asynchrony increased, dichotic vowel fusion decreased and identification performance improved. Onset asynchrony exerted a greater effect on fusion and identification of vowels when Δf o = 0, especially in HI listeners. Therefore, the temporal cue promotes segregation in both groups of listeners, especially in HI listeners when the f o cue was unavailable.

Supporting Equity and Inclusion of Deaf and Hard-of-Hearing Individuals in Professional Organizations.

Disability is an important and often overlooked component of diversity. Individuals with disabilities bring a rare perspective to science, technology, engineering, mathematics, and medicine (STEMM) because of their unique experiences approaching complex issues related to health and disability, navigating the healthcare system, creatively solving problems unfamiliar to many individuals without disabilities, managing time and resources that are limited by physical or mental constraints, and advocating for themselves and others in the disabled community. Yet, individuals with disabilities are underrepresented in STEMM. Professional organizations can address this underrepresentation by recruiting individuals with disabilities for leadership opportunities, easing financial burdens, providing equal access, fostering peer-mentor groups, and establishing a culture of equity and inclusion spanning all facets of diversity. We are a group of deaf and hard-of-hearing (D/HH) engineers, scientists, and clinicians, most of whom are active in clinical practice and/or auditory research. We have worked within our professional societies to improve access and inclusion for D/HH individuals and others with disabilities. We describe how different models of disability inform our understanding of disability as a form of diversity. We address heterogeneity within disabled communities, including intersectionality between disability and other forms of diversity. We highlight how the Association for Research in Otolaryngology has supported our efforts to reduce ableism and promote access and inclusion for D/HH individuals. We also discuss future directions and challenges. The tools and approaches discussed here can be applied by other professional organizations to include individuals with all forms of diversity in STEMM.

Binaural Pitch Fusion in Children With Normal Hearing, Hearing Aids, and Cochlear Implants.

OBJECTIVES: Binaural pitch fusion is the perceptual integration of stimuli that evoke different pitches between the ears into a single auditory image. Adults who use hearing aids (HAs) or cochlear implants (CIs) often experience abnormally broad binaural pitch fusion, such that sounds differing in pitch by as much as 3 to 4 octaves are fused across ears, leading to spectral averaging and speech perception interference. The main goal of this study was to measure binaural pitch fusion in children with different hearing device combinations and compare results across groups and with adults. A second goal was to examine the relationship of binaural pitch fusion to interaural pitch differences or pitch match range, a measure of sequential pitch discriminability. DESIGN: Binaural pitch fusion was measured in children between the ages of 6.1 and 11.1 years with bilateral HAs (n = 9), bimodal CI (n = 10), bilateral CIs (n = 17), as well as normal-hearing (NH) children (n = 21). Depending on device combination, stimuli were pure tones or electric pulse trains delivered to individual electrodes. Fusion ranges were measured using simultaneous, dichotic presentation of reference and comparison stimuli in opposite ears, and varying the comparison stimulus to find the range that fused with the reference stimulus. Interaural pitch match functions were measured using sequential presentation of reference and comparison stimuli, and varying the comparison stimulus to find the pitch match center and range. RESULTS: Children with bilateral HAs had significantly broader binaural pitch fusion than children with NH, bimodal CI, or bilateral CIs. Children with NH and bilateral HAs, but not children with bimodal or bilateral CIs, had significantly broader fusion than adults with the same hearing status and device configuration. In children with bilateral CIs, fusion range was correlated with several variables that were also correlated with each other: pure-tone average in the second implanted ear before CI, and duration of prior bilateral HA, bimodal CI, or bilateral CI experience. No relationship was observed between fusion range and pitch match differences or range. CONCLUSIONS: The findings suggest that binaural pitch fusion is still developing in this age range and depends on hearing device combination but not on interaural pitch differences or discriminability.