The Effects of Symbol Format and Psycholinguistic Features on Receptive Syntax Outcomes of Children Without Disability.

PURPOSE: The graphic symbol is the foundation of augmentative and alternative communication (AAC) for many preliterate individuals; however, research has focused primarily on static graphic symbol sequences despite mainstream commercial technologies such as animation. The goal of this study was to compare static and animated symbol sequences across receptive communication outcome measures and psycholinguistic features (e.g., word frequency). METHOD: A counterbalanced, 2 × 2 × 2 mixed design was used to investigate the effects of symbol format (animated and static), first condition (animated or static), and first experimental task (identification or labeling) on identification accuracy and labeling accuracy of graphic symbol sequences (five symbols) in 24 children with typical development ages 7 and 8 years old. Additionally, three 2 × 2 repeated-measures analyses of variance were conducted using symbol format (animated and static) and (a) word frequency (low, high), (b) imageability (low, high), and (c) concreteness (low, high). RESULTS: In addition to superior identification and labeling accuracy of animated sequences, a significant interaction between symbol format and the first condition was observed for both experimental tasks. When the animation format was the first condition, then the children's performance improved in the subsequent static condition. Finally, word frequency, imageability, and concreteness ratings for all verbs and prepositions had significant effects on labeling accuracy of verbs and prepositions. Significant interactions between symbol format and psycholinguistic features were also found. For example, highly imageable, animated verbs were labeled with greater accuracy when compared with all other variables. CONCLUSIONS: Animation technology appears to alleviate some of the burden associated with word- and sentence-level outcomes in children with typical development. Moreover, animation appears to reduce the effects of psycholinguistic features such as word frequency and imageability by increasing the transparency of the symbol. Given the increase in research in this area, speech-language pathologists may consider adopting animated graphic symbols on a case-by-case basis as a tool to augment the learning of word classes in which movement is integral to comprehension.

Phonological Underspecification: An Explanation for How a Rake Can Become Awake.

Neural markers, such as the mismatch negativity (MMN), have been used to examine the phonological underspecification of English feature contrasts using the Featurally Underspecified Lexicon (FUL) model. However, neural indices have not been examined within the approximant phoneme class, even though there is evidence suggesting processing asymmetries between liquid (e.g., /ɹ/) and glide (e.g., /w/) phonemes. The goal of this study was to determine whether glide phonemes elicit electrophysiological asymmetries related to [consonantal] underspecification when contrasted with liquid phonemes in adult English speakers. Specifically, /ɹɑ/ is categorized as [+consonantal] while /wɑ/ is not specified [i.e., (-consonantal)]. Following the FUL framework, if /w/ is less specified than /ɹ/, the former phoneme should elicit a larger MMN response than the latter phoneme. Fifteen English-speaking adults were presented with two syllables, /ɹɑ/ and /wɑ/, in an event-related potential (ERP) oddball paradigm in which both syllables served as the standard and deviant stimulus in opposite stimulus sets. Three types of analyses were used: (1) traditional mean amplitude measurements; (2) cluster-based permutation analyses; and (3) event-related spectral perturbation (ERSP) analyses. The less specified /wɑ/ elicited a large MMN, while a much smaller MMN was elicited by the more specified /ɹɑ/. In the standard and deviant ERP waveforms, /wɑ/ elicited a significantly larger negative response than did /ɹɑ/. Theta activity elicited by /ɹɑ/ was significantly greater than that elicited by /wɑ/ in the 100-300 ms time window. Also, low gamma activation was significantly lower for /ɹɑ/ vs. /wɑ/ deviants over the left hemisphere, as compared to the right, in the 100-150 ms window. These outcomes suggest that the [consonantal] feature follows the underspecification predictions of FUL previously tested with the place of articulation and voicing features. Thus, this study provides new evidence for phonological underspecification. Moreover, as neural oscillation patterns have not previously been discussed in the underspecification literature, the ERSP analyses identified potential new indices of phonological underspecification.

Evidence for [Coronal] Underspecification in Typical and Atypical Phonological Development.

The Featurally Underspecified Lexicon (FUL) theory predicts that [coronal] is the language universal default place of articulation for phonemes. This assumption has been consistently supported with adult behavioral and event-related potential (ERP) data; however, this underspecification claim has not been tested in developmental populations. The purpose of this study was to determine whether children demonstrate [coronal] underspecification patterns similar to those of adults. Two English consonants differing in place of articulation, [labial] /b/ and [coronal] /d/, were presented to 24 children (ages 4-6 years) characterized by either a typically developing phonological system (TD) or a phonological disorder (PD). Two syllables, /bɑ/ and /dɑ/, were presented in an ERP oddball paradigm where both syllables served as the standard and deviant stimulus in opposite stimulus sets. Underspecification was examined with three analyses: traditional mean amplitude measurements, cluster-based permutation tests, and single-trial general linear model (GLM) analyses of single-subject data. Contrary to previous adult findings, children with PD demonstrated a large positive mismatch response (PMR) to /bɑ/ while the children with TD exhibited a negative mismatch response (MMN); significant group differences were not observed in the /dɑ/ responses. Moreover, the /bɑ/ deviant ERP response was significantly larger in the TD children than in the children with PD. At the single-subject level, more children demonstrated mismatch responses to /dɑ/ than to /bɑ/, though some children had a /bɑ/ mismatch response and no /dɑ/ mismatch response. While both groups of children demonstrated similar responses to the underspecified /dɑ/, their neural responses to the more specified /bɑ/ varied. These findings are interpreted within a proposed developmental model of phonological underspecification, wherein children with PD are functioning at a developmentally less mature stage of phonological acquisition than their same-aged TD peers. Thus, phonological underspecification is a phenomenon that likely develops over time with experience and exposure to language.

Speech Intervention Outcomes Associated With Word Lexicality and Intervention Intensity.

Purpose This study examined how lexical representations and intervention intensity affect phonological acquisition and generalization in children with speech sound disorders. Method Using a single-subject multiple baseline design, 24 children with speech sound disorders (3;6 to 6;10 [years;months]) were split into 3 word lexicality types targeting word-initial complex singleton phonemes: /ɹ l ʧ θ/. Specifically, academic vocabulary words, nonwords (NWs), and high-frequency (HF) words were contrasted. Intervention intensity was examined by comparing the performance of 12 children who completed eleven 50-min sessions (4 children/word type) to the performance of 12 who completed 19 sessions (4 children/word type). Children's production accuracy of their treated phonemes and overall percent consonants correct values were used to measure phonological generalization via percentage accuracy scores and d scores. Results All word lexicality conditions elicited phonological change, suggesting that academic vocabulary words, NWs, and HF words are viable intervention targets. Group mean averages were similarly high for the NWs and HF words, although children in the NW condition demonstrated more consistent phonological gains. Children who received 19 intervention sessions achieved 6 times more gains in treated sound accuracy than did children who received 11 sessions. Conclusions Word lexicality did not significantly influence children's intervention outcomes. More intensive intervention, as characterized by the number sessions, resulted in greater phonological change than did a shorter intervention program. Intervention intensity outcomes should be considered when establishing best practices for speech intervention scheduling. Supplemental Material https://doi.org/10.23641/asha.7336055.

Converging evidence for [coronal] underspecification in English-speaking adults.

The goal of this study was to test the predictions of the Featurally Underspecified Lexicon (FUL) theory by examining event-related potential (ERP) indices of phonological representation. Two English consonants differing in place of articulation were selected: [labial] /b/ and [coronal] /d/. It was assumed that the phonological representation of /d/ contained less distinctive feature information due to its [coronal] place of articulation, as compared to /b/. English-speaking adults were presented with two syllables, /bɑ/ and /dɑ/, in an ERP oddball paradigm where both syllables served as the standard and deviant stimulus in opposite stimulus sets. Three types of analyses were conducted: traditional mean amplitude measurements, cluster-based permutation tests, and single-trial general linear model (GLM) analyses of group-level and single-subject data. The less specified /dɑ/ deviant elicited a large MMN while no MMN was elicited by the more specified deviant /bɑ/. Additionally, the /dɑ/ standard syllable elicited larger responses than did the /bɑ/ standard, while deviant syllables did not differ. This implies that the MMN was driven by responses elicited by the standards rather than the deviants. At the single-subject level, not all participants demonstrated significant MMN responses, though all had measurable differences between the standard syllables. Thus, to continue to propose that [coronal] underspecification is a language universal phenomenon, ERP indices other than the MMN should be examined.

Phonological code retrieval during picture naming: Influence of consonant class.

Investigations of the time course of various stages of lexical processing have indicated either early or late onset of brain activation for phonological code retrieval. The basis of the differential findings is unclear, but factors related to segmental phonology appear to be part of it. The purpose of the present study was to determine whether phonological encoding is influenced by consonant type. Undergraduate students were presented pictures of common and familiar objects to name. Each picture label had an initial liquid (/l/, /ɹ/) or a stop (/b/, /d/) consonant. Accuracy of picture naming was high and comparable for the two stimulus sets. However, words beginning with liquids elicited larger N2 ERP responses than did those with initial stops. Cluster permutation analysis indicated that the ERP responses elicited by words in the two stimulus sets differed between 293 ms and 371 ms post picture onset. These findings point to a late onset of phonological code retrieval. They have implications for segmental phonology and/or motor planning and execution of speech.

A comparison of word lexicality in the treatment of speech sound disorders.

The goal of this research programme was to evaluate the role of word lexicality in effecting phonological change in children's sound systems. Four children with functional speech sound disorders (SSDs) were enrolled in an across-subjects multiple baseline single-subject design; two were treated using high-frequency real words (RWs) and two were treated using (low-frequency) non-words (NWs). Dependent variables were learning during treatment, generalization of treated and untreated sounds post-treatment and error consistency indices. The oldest child in the NW group demonstrated slightly greater increases in learning during treatment, and both children demonstrated increases in generalization as well as large decreases in sound error variability. In comparison, one child in the RW group demonstrated untreated sound generalization, as well as decreases in sound error variability. These results suggest that NWs may be useful in helping children learn the sound structure of words containing treated sounds. These findings are interpreted within an established connectionist model accounting for phonological and lexical representations.

Verbal and nonverbal semantic processing in children with developmental language impairment.

In an effort to clarify whether semantic integration is impaired in verbal and nonverbal auditory domains in children with developmental language impairment (a.k.a., LI and SLI), the present study obtained behavioral and neural responses to words and environmental sounds in children with language impairment and their typically developing age-matched controls (ages 7-15 years). Event-related brain potentials (ERPs) were recorded while children performed a forced-choice matching task on semantically matching and mismatching visual-auditory, picture-word and picture-environmental sound pairs. Behavioral accuracy and reaction time measures were similar for both groups of children, with environmental sounds eliciting more accurate responses than words. In picture-environmental sound trials, behavioral performance and the brain's response to semantic incongruency (i.e., the N400 effect) of the children with language impairment were comparable to those of their typically developing peers. However, in picture-word trials, children with LI tended to be less accurate than their controls and their N400 effect was significantly delayed in latency. Thus, the children with LI demonstrated a semantic integration deficit that was somewhat specific to the verbal domain. The particular finding of a delayed N400 effect is consistent with the storage deficit hypothesis of language impairment (Kail & Leonard, 1986) suggesting weakened and/or less efficient connections within the language networks of children with LI.

Infants' recognition of meaningful verbal and nonverbal sounds.

To examine how young children recognize the association between two different types of meaningful sounds and their visual referents, we compared 15-, 20-, and 25-month-old infants' looking time responses to familiar naturalistic environmental sounds, (e.g., the sound of a dog barking) and their empirically matched verbal descriptions (e.g., "Dog barking") in an intermodal preferential looking paradigm. Across all three age groups, performance was indistinguishable over the two domains. Infants with the largest vocabularies were more accurate in processing the verbal phrases than the environmental sounds. However, after taking into account each child's verbal comprehension/production and the onomatopoetic test items, all cross-domain differences disappeared. Correlational analyses revealed that the processing of environmental sounds was tied to chronological age, while the processing of speech was linked to verbal proficiency. Overall, while infants' ability to recognize the two types of sounds did not differ behaviorally, the underlying processes may differ depending on the type of auditory input.

A developmental ERP study of verbal and non-verbal semantic processing.

To clarify how different the processing of verbal information is from the processing of meaningful non-verbal information, the present study characterized the developmental changes in neural responses to words and environmental sounds from pre-adolescence (7-9 years) through adolescence (12-14 years) to adulthood (18-25 years). Children and adults' behavioral and electrophysiological responses (the N400 effect of event-related potentials) were compared during the processing of words and environmental sounds presented in semantically matching and mismatching picture contexts. Behavioral accuracy of picture-sound matching improved until adulthood, while reaction time measures leveled out by age 12. No major electrophysiological changes in the N400 effect were observed between pre-adolescence and adolescence. When compared to adults, children demonstrated significant maturational changes including longer latencies and larger amplitudes of the N400 effect. Interestingly, these developmental differences were driven by stimulus type: the Environmental Sound N400 effect decreased in latency from adolescence to adulthood, while no age effects were observed in response to Words. Thus, while the semantic processing of single words is well established by 7 years of age, the processing of environmental sounds continues to improve throughout development.