The hair bundle--the sensory organelle of inner-ear hair cells of vertebrates--exemplifies the ability of a cell to assemble complex, elegant structures. Proper construction of the bundle is required ...for proper mechanotransduction in response to external forces and to transmit information about sound and movement. Bundles contain tightly controlled numbers of actin-filled stereocilia, which are arranged in defined rows of precise heights. Indeed, many deafness mutations that disable hair-cell cytoskeletal proteins also disrupt bundles. Bundle assembly is a tractable problem in molecular and cellular systems biology; the sequence of structural changes in stereocilia is known, and a modest number of proteins may be involved.
Deaf individuals have been known to process visual stimuli better at the periphery compared to the normal hearing population. However, very few studies have examined attention orienting in the ...oculomotor domain in the deaf, particularly when targets appear at variable eccentricity. In this study, we examined if the visual perceptual processing advantage reported in the deaf people also modulates spatial attentional orienting with eye movement responses. We used a spatial cueing task with cued and uncued targets that appeared at two different eccentricities and explored attentional facilitation and inhibition. We elicited both a saccadic and a manual response. The deaf showed a higher cueing effect for the ocular responses than the normal hearing participants. However, there was no group difference for the manual responses. There was also higher facilitation at the periphery for both saccadic and manual responses, irrespective of groups. These results suggest that, owing to their superior visual processing ability, the deaf may orient attention faster to targets. We discuss the results in terms of previous studies on cueing and attentional orienting in deaf.
Outcomes following cochlear implantation in children with X-linked deafness-2 are variable, resulting in challenges in appropriate preoperative counseling. To address this uncertainty, we performed a ...systematic review and synthesis of the literature on audiologic and speech outcomes after cochlear implantation in these patients to inform prognostic counseling.
PubMed, Embase, and Cochrane Library were queried for articles published between January 2000 and July 2019.
We performed a systematic review of all studies published between 2000 and 2019 that reported on (1) children with confirmed X-linked deafness-2 undergoing cochlear implantation and (2) formal assessment of hearing and/or speech capabilities postimplantation.
Our initial database search yielded 313 articles. Fourteen articles met inclusion criteria. These studies reported on 61 children with X-linked deafness-2 who underwent implantation at a wide age range (1-29 years) for severe-profound sensorineural hearing loss of prelingual onset. The mean follow-up duration after implant activation was 32 months (range, 12-61). Outcome domains assessed at follow-up were heterogeneous, though each study employed at least 1 assessment of hearing (eg, pure tone audiometry), speech perception (eg, Early Speech Perception Test), or auditory perception (eg, Categories of Auditory Perception scores). In 10 of 14 studies, cochlear implantation afforded significant improvement in hearing and speech capabilities relative to preoperative performance or as compared with age-matched, normal-hearing controls.
The majority of studies demonstrate that cochlear implantation provides improvements in hearing and speech performance in patients with X-linked deafness-2. This information is valuable for decision making regarding cochlear implantation in these patients.
Early identification and intervention for developmental disorders are critical to the well-being of children and are the responsibility of pediatric professionals as an integral function of the ...medical home. This report models a universal system of developmental surveillance and screening for the early identification of conditions that affect children's early and long-term development and achievement, followed by ongoing care. These conditions include autism, deafness/hard-of-hearing, intellectual and motor disabilities, behavioral conditions, and those seen in other medical conditions. Developmental surveillance is supported at every health supervision visit, as is as the administration of standardized screening tests at the 9-, 18-, and 30-month visits. Developmental concerns elicited on surveillance at any visit should be followed by standardized developmental screening testing or direct referral to intervention and specialty medical care. Special attention to surveillance is recommended at the 4- to 5-year well-child visit, prior to entry into elementary education, with screening completed if there are any concerns. Developmental surveillance includes bidirectional communication with early childhood professionals in child care, preschools, Head Start, and other programs, including home visitation and parenting, particularly around developmental screening. The identification of problems should lead to developmental and medical evaluations, diagnosis, counseling, and treatment, in addition to early developmental intervention. Children with diagnosed developmental disorders are identified as having special health care needs, with initiation of chronic condition management in the pediatric medical home.
Congenitally deaf individuals receive little or no auditory input, and when raised by deaf parents, they acquire sign as their native and primary language. We asked two questions regarding how the ...deaf brain in humans adapts to sensory deprivation: (1) is meaning extracted and integrated from signs using the same classical left hemisphere frontotemporal network used for speech in hearing individuals, and (2) in deafness, is superior temporal cortex encompassing primary and secondary auditory regions reorganized to receive and process visual sensory information at short latencies? Using MEG constrained by individual cortical anatomy obtained with MRI, we examined an early time window associated with sensory processing and a late time window associated with lexicosemantic integration. We found that sign in deaf individuals and speech in hearing individuals activate a highly similar left frontotemporal network (including superior temporal regions surrounding auditory cortex) during lexicosemantic processing, but only speech in hearing individuals activates auditory regions during sensory processing. Thus, neural systems dedicated to processing high-level linguistic information are used for processing language regardless of modality or hearing status, and we do not find evidence for rewiring of afferent connections from visual systems to auditory cortex.
Aim
To monitor functional auditory and non‐verbal cognitive skills in children with cochlear implants who had associated disabilities over a 24‐month period and define how cochlear implantation may ...impact on non‐verbal cognition by restoring functional auditory skills.
Method
Sixty‐four children with cochlear implants (36 females, 28 males; mean age 4y 3mo, SD 3y 5mo, 9mo–14y 5mo) were recruited and divided into three groups: children with typical development group (TDG); children with associated disabilities not linked to non‐verbal cognitive disorders group (ADG1); and children with associated disabilities linked to non‐verbal cognitive disorders group (ADG2). Tests of functional auditory, communicative, and non‐verbal cognitive skills were performed before cochlear implantation and at 12 and 24 months after cochlear implantation.
Results
Functional auditory and communicative skills improved similarly in the three groups at 12 and 24 months after implantation. An increase in non‐verbal cognitive scores was present in children in the ADG2 from baseline to 12 and 24 months (p<0.01), whereas scores remained stable in children in the TDG and ADG1. The increased functional auditory skills scores after cochlear implantation corresponded to an increase in non‐verbal cognitive scores (p=0.032) in children in the ADG2.
Interpretation
Children with associated disabilities, especially if linked to non‐verbal cognitive disorders, benefitted from cochlear implantation. They improved their comprehension of acoustic information inferred from the environment, improving not only functional auditory skills but also non‐verbal cognition.
This article is commented on by Meinzen‐Derr on page 1348 of this issue.
Purpose: The goal of this study was to investigate the effect of age on phoneme recognition performance in which the stimuli varied in the amount of temporal information available in the signal. ...Chronological age is increasingly recognized as a factor that can limit the amount of benefit an individual can receive from a cochlear implant (CI). Central auditory temporal processing deficits in older listeners may contribute to the performance gap between younger and older CI users on recognition of phonemes varying in temporal cues. Method: Phoneme recognition was measured at three stimulation rates (500, 900, and 1800 pulses per second) and two envelope modulation frequencies (50 Hz and unfiltered) in 20 CI participants ranging in age from 27 to 85 years. Speech stimuli were multiple word pairs differing in temporal contrasts and were presented via direct stimulation of the electrode array using an eight-channel continuous interleaved sampling strategy. Phoneme recognition performance was evaluated at each stimulation rate condition using both envelope modulation frequencies. Results: Duration of deafness was the strongest subject-level predictor of phoneme recognition, with participants with longer durations of deafness having poorer performance overall. Chronological age did not predict performance for any stimulus condition. Additionally, duration of deafness interacted with envelope filtering. Participants with shorter durations of deafness were able to take advantage of higher frequency envelope modulations, while participants with longer durations of deafness were not. Conclusions: Age did not significantly predict phoneme recognition performance. In contrast, longer durations of deafness were associated with a reduced ability to utilize available temporal information within the signal to improve phoneme recognition performance.
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