Morphosyntactic profiles among preschoolers with and without speech sound disorders.

The aim of the current study was to identify whether certain morphosyntactic constructs are more difficult for children with speech sound disorder than children with typical speech development. In this post-hoc study, we used chi-square analyses to identify group differences on individual questions on a standardised test of expressive morphosyntax. Participants included 80 preschool-age children, 40 with typical speech and language development (TD), and 40 with speech sound disorder and typical language development (SSD). A chi-square analysis revealed group (TD vs. SSD) differences in usage of subject pronouns, irregular past tense verbs, and yes/no interrogative formation. Ordinal logistic regression revealed that phonological awareness was related to irregular past tense verb use. Children with SSD may present with subclinical morphosyntax difficulties. Speech-language pathologists should consider incorporating morphosyntax assessment into test batteries for children with SSD.

Aqueous Co removal by mycogenic Mn oxides from simulated mining wastewaters.

Naturally occurring manganese (Mn) oxide minerals often form by microbial Mn(II) oxidation, resulting in nanocrystalline Mn(III/IV) oxide phases with high reactivity that can influence the uptake and release of many metals (e.g., Ni, Cu, Co, and Zn). During formation, the structure and composition of biogenic Mn oxides can be altered in the presence of other metals, which in turn affects the minerals' ability to bind these metals. These processes are further influenced by the chemistry of the aqueous environment and the type and physiology of microorganisms involved. Conditions extending to environments that typify mining and industrial wastewaters (e.g., increased salt content, low nutrient, and high metal concentrations) have not been well investigated thus limiting the understanding of metal interactions with biogenic Mn oxides. By integrating geochemistry, microscopic, and spectroscopic techniques, we examined the capacity of Mn oxides produced by the Mn(II)-oxidizing Ascomycete fungus Periconia sp. SMF1 isolated from the Minnesota Soudan Mine to remove the metal co-contaminant Co(II) from synthetic waters that are representative of mining wastewaters currently undergoing remediation efforts. We compared two different applied remediation strategies under the same conditions: coprecipitation of Co with mycogenic Mn oxides versus adsorption of Co with pre-formed fungal Mn oxides. Co(II) was effectively removed from solution by fungal Mn oxides through two different mechanisms: incorporation into, and adsorption onto, Mn oxides. These mechanisms were similar for both remediation strategies, indicating the general effectiveness of Co(II) removal by these oxides. The mycogenic Mn oxides were primarily a nanoparticulate, poorly-crystalline birnessite-like phases with slight differences depending on the chemical conditions during formation. The relatively fast and complete removal of aqueous Co(II) during biomineralization as well as the subsequent structural incorporation of Co into the Mn oxide structure illustrated a sustainable cycle capable of continuously remediating Co(II) from metal-polluted environments.

The Effect of Somatosensory Input on Word Recognition in Typical Children and Those With Speech Sound Disorder.

PURPOSE: Recent work suggests that speech perception is influenced by the somatosensory system and that oral sensorimotor disruption has specific effects on the perception of speech both in infants who have not yet begun to talk and in older children and adults with ample speech production experience; however, we do not know how such disruptions affect children with speech sound disorder (SSD). Response to disruption of would-be articulators during speech perception could reveal how sensorimotor linkages work for both typical and atypical speech and language development. Such linkages are crucial to advancing our knowledge on how both typically developing and atypically developing children produce and perceive speech. METHOD: Using a looking-while-listening task, we explored the impact of a sensorimotor restrictor on the recognition of words whose onsets involve late-developing sounds (s, ʃ) for both children with typical development (TD) and their peers with SSD. RESULTS: Children with SSD showed a decrement in performance when they held a restrictor in their mouths during the task, but this was not the case for children with TD. This effect on performance was only observed for the specific speech sounds blocked by the would-be articulators. CONCLUSION: We argue that these findings provide evidence for altered perceptual motor pathways in children with SSD. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.21809442.

Speech Error Variability and Phonological Awareness in Preschoolers.

PURPOSE: The purpose of this article was to investigate the relationship between speech error variability and phonological awareness. METHOD: This article begins with a narrative review of the theoretical interpretation of speech error variability. The post hoc exploratory analysis of the relationship between speech error variability and phonological awareness included 40 children: 20 with typical speech and language and 20 with speech sound disorder and typical language. Groups were matched on gender, age, maternal education, receptive and expressive vocabulary, nonverbal intelligence, and expressive morphosyntax. Multiple regression was used to identify the best fit model for the relationship between vocabulary, speech errors, and phonological awareness. RESULTS: Segmental variability was associated with poor phonological awareness in preschool-aged children. CONCLUSION: Children with high levels of segmental variability have poor phonological awareness, likely due to unstable phonological representations.

Implementing Speech Perception and Phonological Awareness Intervention for Children With Speech Sound Disorders.

PURPOSE: Children with speech sound disorders have more difficulties producing speech sounds accurately than same-age peers. In addition, they often have difficulties with speech perception, and weaker phonological awareness skills than their peers and are at risk for negative long-term academic and socio-emotional outcomes. In this tutorial, we describe ways in which clinicians can target speech perception and/or phonological awareness within the context of speech production practice. METHOD: First, we briefly describe the speech perception and phonological awareness skills of children with speech sound disorders and summarize previous intervention studies that targeted speech production and speech perception and/or phonological awareness skills. Next, we demonstrate how clinicians may incorporate speech perception and phonological awareness intervention in speech therapy through example instructional objectives and activities and include a case study. CONCLUSION: Incorporating speech perception and phonological awareness into speech production intervention may improve speech and literacy outcomes for children with speech sound disorders.

Vowel errors produced by preschool-age children on a single-word test of articulation.

Eighty-four children, age 4-5 years, with and without speech sound disorder (SSD) completed a battery of standardized speech and language tests, including the Goldman-Fristoe Test of Articulation, Third Edition (GFTA-3). Children with SSD produced more vowel errors than children with typical speech abilities. Percentage vowels correct and consonant error variability were highly correlated, suggesting that poorly specified phonological representations affect both consonants and vowels within a child's phonological system. However, the GFTA-3 did not contain sufficient target words to determine full vowel inventory. Using words from the GFTA-3, we present a case study of a child with vowel errors along with a sample analysis of these errors, primarily in terms of consonant-vowel feature interactions. Children who exhibit vowel errors on standardized single-word tests of speech accuracy may benefit from further vowel probes to determine how vowel and consonant errors interact in their phonological systems for more targeted therapy.

The Speech "Bamana": Using the Syllable Repetition Task to Identify Underlying Phonological Deficits in Children With Speech and Language Impairments.

Purpose This study compared performance on the Syllable Repetition Task (SRT) by preschoolers with diverse speech and language abilities to identify underlying impairments in speech processes. Method Three groups of 13 children ages 4 and 5 years with (a) typically developing (TD) speech and language, (b) speech sound disorder (SSD), and (c) comorbid developmental language disorder and speech sound disorder (DLD + SSD) completed the SRT. We calculated competence, memory, encoding, and transcoding scores, as well as word-initial stress pattern and vowel accuracy. Results A 3 × 3 (Group × Syllable length) factorial multivariate analysis of covariance revealed group differences for all measures and syllable length differences for memory, transcoding, and competence. There were no interactions between group and syllable length. TD children obtained the highest scores on each measure, though children with DLD + SSD performed similarly to TD children on encoding when vocabulary was included as a covariate. Children with SSD only outperformed children with DLD + SSD on competence and transcoding, and these two groups performed similarly on memory. A separate exploratory analysis using a 3 × 3 multivariate analysis of covariance revealed that children with DLD + SSD were more likely than children in the other groups to produce weak word-initial stress and vowel errors during syllable repetition. Conclusion Children with SSD and DLD + SSD exhibit underlying phonological deficits on the SRT compared to TD children. Results support the claim that memory and encoding are deficits in SSD. In addition, transcoding deficits were identified among children with no known oromotor impairment. Therefore, more research is required to identify the relationship between SRT performance and explicit measures of phonological processing.

Perception of Sibilants by Preschool Children With Overt and Covert Sound Contrasts.

Purpose This study explores the role of overt and covert contrasts in speech perception by children with speech sound disorder (SSD). Method Three groups of preschool-aged children (typically developing speech and language [TD], SSD with /s/~/ʃ/ contrast [SSD-contrast], and SSD with /s/~/ʃ/ collapse [SSD-collapse]) completed an identification task targeting /s/~/ʃ/ minimal pairs. The stimuli were produced by 3 sets of talkers: children with TD, children with SSD, and the participant himself/herself. We conducted a univariate general linear model to investigate differences in perception of tokens produced by different speakers and differences in perception between the groups of listeners. Results The TD and SSD-contrast groups performed similarly when perceiving tokens produced by themselves or other children. The SSD-collapse group perceived all speakers more poorly than the other 2 groups of children, performing at chance for perception of their own speech. Children who produced a covert contrast did not perceive their own speech more accurately than children who produced no identifiable acoustic contrast. Conclusion Preschool-aged children have not yet developed adultlike phonological representations. Collapsing phoneme production, even with a covert contrast, may indicate poor perception of the collapsed phonemes.

Speech Errors and Phonological Awareness in Children Ages 4 and 5 Years With and Without Speech Sound Disorder.

Purpose The aim of this study was to examine the relationship between types of speech errors produced by children with speech sound disorders (SSD) and children with typical speech and language development (TD) and phonological awareness (PA) skills. Method Participants were 40 children, half with SSD and half with TD, ages 4 and 5 years. They completed standard speech, language, and PA tests as well as produced single words varying in length from 1 to 5 syllables. Production of each consonant was classified as either correct production, omission, substitution, and distortion; errors were also classified as typical or atypical. Results The children with SSD produced similar proportions of each type of speech errors in mono-, di-, and multisyllabic words. In contrast, the children with TD produced much lower, but not significantly different, proportions of omissions, substitutions, distortions, and typical speech errors at each word length. They produced no atypical errors in monosyllabic words and were significantly more likely to produce them in multisyllabic words. Proportions of omissions and atypical speech errors were significantly correlated with PA performance. Variance in PA skills was predicted partly by vocabulary, language skills, and age; omissions accounted for an additional 5% of variance in PA. Other types of speech errors did not account for additional significant variance in PA performance. Conclusions Poorer PA skills were found to be associated with omissions and atypical speech errors. Research is required to investigate the potential of omission and atypical error use in predicting which children are likely to receive diagnoses of SSD and later literacy difficulties.

Complete Genome Sequence of Sulfuriferula sp. Strain AH1, a Sulfur-Oxidizing Autotroph Isolated from Weathered Mine Tailings from the Duluth Complex in Minnesota.

We report the closed and annotated genome sequence of Sulfuriferula sp. strain AH1. Strain AH1 has a 2,877,007-bp chromosome that includes a partial Sox system for inorganic sulfur oxidation and a complete nitrogen fixation pathway. It also has a single 39,138-bp plasmid with genes for arsenic and mercury resistance.

Novel Microbial Assemblages Dominate Weathered Sulfide-Bearing Rock from Copper-Nickel Deposits in the Duluth Complex, Minnesota, USA.

The Duluth Complex in northeastern Minnesota hosts economically significant deposits of copper, nickel, and platinum group elements (PGEs). The primary sulfide mineralogy of these deposits includes the minerals pyrrhotite, chalcopyrite, pentlandite, and cubanite, and weathering experiments show that most sulfide-bearing rock from the Duluth Complex generates moderately acidic leachate (pH 4 to 6). Microorganisms are important catalysts for metal sulfide oxidation and could influence the quality of water from mines in the Duluth Complex. Nevertheless, compared with that of extremely acidic environments, much less is known about the microbial ecology of moderately acidic sulfide-bearing mine waste, and so existing information may have little relevance to those microorganisms catalyzing oxidation reactions in the Duluth Complex. Here, we characterized the microbial communities in decade-long weathering experiments (kinetic tests) conducted on crushed rock and tailings from the Duluth Complex. Analyses of 16S rRNA genes and transcripts showed that differences among microbial communities correspond to pH, rock type, and experimental treatment. Moreover, microbial communities from the weathered Duluth Complex rock were dominated by taxa that are not typically associated with acidic mine waste. The most abundant operational taxonomic units (OTUs) were from the genera Meiothermus and Sulfuriferula, as well as from diverse clades of uncultivated Chloroflexi, Acidobacteria, and Betaproteobacteria Specific taxa, including putative sulfur-oxidizing Sulfuriferula spp., appeared to be primarily associated with Duluth Complex rock, but not pyrite-bearing rocks subjected to the same experimental treatment. We discuss the implications of these results for the microbial ecology of moderately acidic mine waste with low sulfide content, as well as for kinetic testing of mine waste.IMPORTANCE Economic sulfide mineral deposits in the Duluth Complex may represent the largest undeveloped source of copper and nickel on Earth. Microorganisms are important catalysts for sulfide mineral oxidation, and research on extreme acidophiles has improved our ability to manage and remediate mine wastes. We found that the microbial assemblages associated with weathered rock from the Duluth Complex are dominated by organisms not widely associated with mine waste or mining-impacted environments, and we describe geochemical and experimental influences on community composition. This report will be a useful foundation for understanding the microbial biogeochemistry of moderately acidic mine waste from these and similar deposits.