Speech and Language Outcomes in Adults and Children with Cochlear Implants

Cochlear implants (CIs) represent a significant engineering and medical milestone in the treatment of hearing loss for both adults and children. In this review, we provide a brief overview of CI technology, describe the benefits that CIs can provide to adults and children who receive them, and discuss the specific limitations and issues faced by CI users. We emphasize the relevance of CIs to the linguistics community by demonstrating how CIs successfully provide access to spoken language. Furthermore, CI research can inform our basic understanding of spoken word recognition in adults and spoken language development in children. Linguistics research can also help us address the major clinical issue of outcome variability and motivate the development of new clinical tools to assess the unique challenges of adults and children with CIs, as well as novel interventions for individuals with poor outcomes.

Neonatal brain injury influences structural connectivity and childhood functional outcomes

Neonatal brain injury may impact brain development and lead to lifelong functional impairments. Hypoxic-ischemic encephalopathy (HIE) and congenital heart disease (CHD) are two common causes of neonatal brain injury differing in timing and mechanism. Maturation of whole-brain neural networks can be quantified during development using diffusion magnetic resonance imaging (dMRI) in combination with graph theory metrics. DMRI of 35 subjects with CHD and 62 subjects with HIE were compared to understand differences in the effects of HIE and CHD on the development of network topological parameters and functional outcomes. CHD newborns had worse 12–18 month language (P<0.01) and 30 month cognitive (P<0.01), language (P = 0.05), motor outcomes (P = 0.01). Global efficiency, a metric of brain integration, was lower in CHD (P = 0.03) than in HIE, but transitivity, modularity and small-worldness were similar. After controlling for clinical factors known to affect neurodevelopmental outcomes, we observed that global efficiency was highly associated with 30 month motor outcomes (P = 0.02) in both groups. To explore neural correlates of adverse language outcomes in CHD, we used hypothesis-based and data-driven approaches to identify pathways with altered structural connectivity. We found that connectivity strength in the superior longitudinal fasciculus (SLF) tract 2 was inversely associated with expressive language. After false discovery rate correction, a whole connectome edge analysis identified 18 pathways that were hypoconnected in the CHD cohort as compared to HIE. In sum, our study shows that neonatal structural connectivity predicts early motor development after HIE or in subjects with CHD, and regional SLF connectivity is associated with language outcomes. Further research is needed to determine if and how brain networks change over time and whether those changes represent recovery or ongoing dysfunction. This knowledge will directly inform strategies to optimize neurologic functional outcomes after neonatal brain injury.

Speed of Information Processing and Working Memory in Children with Cochlear Implants

Background: Cochlear implants (CIs) restore partial hearing to deaf children, promoting the development of spoken language skills. However, because of reduced auditory and language experience, children who receive CIs are at risk for delays not only in language skills but also in language-related neurocognitive skills such as verbal working memory (VWM - the ability to retain language information in immediate memory concurrently with other cognitive processing). Although VWM delays in children with CIs are well-documented, the foundational processes underlying these delays are less clear. This study investigated the hypotheses that slower speed of information processing during VWM tasks contributes to VWM delays in CI users and that this slower information processing speed is associated with spoken language outcomes. Methods: 25 early-implanted, prelingually-deaf children with CIs and 25 normal-hearing (NH) peers completed tests of VWM, neurocognitive, and speech-language functioning. Speed of information processing during the VWM test was assessed by measuring response latency and average pause duration. Results: Children with CIs showed poorer VWM scores than NH peers, but the groups did not differ on response latencies or pause durations. Response latencies were significantly correlated with VWM capacity, speech, and language outcomes in both groups. Conclusion: Speed of information processing in VWM was similar for children with CIs and NH. In both groups, shorter response latencies (faster speed of execution of the cognitive operations of working memory) were associated with better neurocognitive and spoken language outcomes. In the CI sample, pause durations were inconsistently associated with VWM and language outcomes. Clinical Policy Impact and Implications: Speed of information processing for VWM is associated with core neurocognitive and spoken language outcomes for children with CIs and should be a routine target of assessment and intervention post-implantation.

Dosage, Intensity, and Frequency of Language Therapy for Aphasia: A Systematic Review–Based, Individual Participant Data Network Meta-Analysis

Background and Purpose: Optimizing speech and language therapy (SLT) regimens for maximal aphasia recovery is a clinical research priority. We examined associations between SLT intensity (hours/week), dosage (total hours), frequency (days/week), duration (weeks), delivery (face to face, computer supported, individual tailoring, and home practice), content, and language outcomes for people with aphasia. Methods: Databases including MEDLINE and Embase were searched (inception to September 2015). Published, unpublished, and emerging trials including SLT and ≥10 individual participant data on aphasia, language outcomes, and time post-onset were selected. Patient-level data on stroke, language, SLT, and trial risk of bias were independently extracted. Outcome measurement scores were standardized. A statistical inferencing, one-stage, random effects, network meta-analysis approach filtered individual participant data into an optimal model examining SLT regimen for overall language, auditory comprehension, naming, and functional communication pre-post intervention gains, adjusting for a priori–defined covariates (age, sex, time poststroke, and baseline aphasia severity), reporting estimates of mean change scores (95% CI). Results: Data from 959 individual participant data (25 trials) were included. Greatest gains in overall language and comprehension were associated with >20 to 50 hours SLT dosage (18.37 [10.58–26.16] Western Aphasia Battery–Aphasia Quotient; 5.23 [1.51–8.95] Aachen Aphasia Test–Token Test). Greatest clinical overall language, functional communication, and comprehension gains were associated with 2 to 4 and 9+ SLT hours/week. Greatest clinical gains were associated with frequent SLT for overall language, functional communication (3–5+ days/week), and comprehension (4–5 days/week). Evidence of comprehension gains was absent for SLT ≤20 hours, <3 hours/week, and ≤3 days/week. Mixed receptive-expressive therapy, functionally tailored, with prescribed home practice was associated with the greatest overall gains. Relative variance was <30%. Risk of trial bias was low to moderate; low for meta-biases. Conclusions: Greatest language recovery was associated with frequent, functionally tailored, receptive-expressive SLT, with prescribed home practice at a greater intensity and duration than reports of usual clinical services internationally. These exploratory findings suggest critical therapeutic ranges, informing hypothesis-testing trials and tailoring of clinical services. Registration: URL: https://www.crd.york.ac.uk/PROSPERO/ ; Unique identifier: CRD42018110947.

The Effect of Older Sibling, Postnatal Maternal Stress, and Household Factors on Language Development in Two- to Four-Year-Old Children

Previous literature has shown that family structure affects language development. Here, factors relating to older siblings (their presence in the house, sex and age gap), mothers (maternal stress) and household size and residential crowding were examined to systematically examine the different role of these factors. Data from mother-child dyads in a Singaporean birth cohort, (677-855 dyads; 52% males; 58-61% Chinese, 20-24% Malay, 17-19% Indian) collected when children were 24-, 48-, and 54-months old, were analysed. There was a negative effect of having an older sibling, moderated by the siblings’ age gap, but not by the older sibling’s sex, nor household size or residential crowding. Maternal stress affected language outcomes in some analyses but not others. Implications for understanding the effect of family structure on language development are discussed.

Family Environmental Dynamics Differentially Influence Spoken Language Development in Children With and Without Hearing Loss

Purpose: The aim of this study was to evaluate whether families of children with sensorineural hearing loss (SNHL) are organized similarly to those of typically developing, typically hearing (TH) children and whether the dimensions of family dynamics and environment are related to spoken language development similarly in children with and without SNHL. Method: Primary caregivers of children with SNHL ( n = 63) or TH ( n = 65) completed the Family Environment Scale–Fourth Edition (FES-4) to assess multiple dimensions of family environment. Children's receptive vocabulary was assessed with the Peabody Picture Vocabulary Test–Fourth Edition, and their receptive language was assessed by an age-appropriate version of the Concepts and Following Directions subtest of the Clinical Evaluation of Language Fundamentals and the Sentence Comprehension subscale of the Comprehensive Assessment of Spoken Language–Second Edition. Principal component analysis was used to examine the dimensional structure of the family environment. Results: Three higher order components were derived from FES-4 subscales for both families of children with SNHL and with TH: Supportive, Controlling, and Conflicted. However, the composition of the factors themselves differed between the two groups. For the TH group, most family environment measures on the FES-4 were not associated with language outcomes. In contrast, for children with SNHL, families who were more supportive, less controlling, and less conflicted had children with better language skills. Conclusions: Three well-accepted dimensions of family dynamics and functioning apply to families of children with SNHL, but their composition differs from those of families with TH children. Family environmental dynamics were much more strongly associated with language outcomes in children with SNHL than in their TH peers. The spoken language development of children with SNHL, in particular, is better in families that provide high levels of support for each other and, in particular, low levels of control, disorganization, and conflict, reflecting the fragile nature of their spoken language development.

Effectiveness of Responsivity Intervention Strategies on Prelinguistic and Language Outcomes for Children with Autism Spectrum Disorder: A Systematic Review and Meta-Analysis of Group and Single Case Studies

We conducted a systematic review to identify randomized controlled trials (RCTs) and single case research design (SCRD) studies of children with autism spectrum disorder that evaluate the effectiveness of responsivity intervention techniques for improving prelinguistic and/or language outcomes. Mean effect sizes were moderate and large for RCTs (33 studies; g = 0.36, 95% CI [0.21, 0.51]) and SCRD (34 studies; between-case standardized mean difference = 1.20, 95% CI [0.87, 1.54]) studies, respectively. Visual analysis (37 studies) revealed strong evidence of a functional relation for 45% of the opportunities and no evidence for 53%. Analyses of moderator effects and study quality are presented. Findings provide support for responsivity intervention strategies with more robust support for context-bound outcomes than more generalized outcomes.