Thalamic Aphasia: a Review.

PURPOSE OF REVIEW: Thalamic aphasia is a rare language disorder resulting from lesions to the thalamus. While most patients exhibit mild symptoms with a predominance of lexical-semantic difficulties, variations in phenotype have been described. Overall, the exact mechanisms of thalamic aphasia await empirical research. The article reviews recent findings regarding phenotypes and possible underlying mechanisms of thalamic aphasia. RECENT FINDINGS: Variations in phenotype of thalamic aphasia may be related to different lesion locations. Overall, the thalamus' role in language is thought to be due to its involvement in cortico-thalamic language networks with lesioning of certain nuclei resulting in the diachisis of otherwise interconnected areas. Its possible monitoring function in such a network might be due to its different cellular firing modes. However, no specific evidence has been collected to date. While recent findings show a more distinct understanding of thalamic aphasia phenotypes and possible underlying mechanisms, further research is needed. Additionally, as standard language testing might oftentimes not pick up on its subtle symptoms, thalamic aphasia might be underdiagnosed.

The Impact of Manipulating Attentional Shifting Demands on Preschool Children With Specific Language Impairment.

Purpose This study investigated attentional shifting in preschool children with specific language impairment (SLI) compared to their typically developing peers. Children's attentional shifting capacity was assessed by varying attentional demands. Method Twenty-five preschool children with SLI and 25 age-matched, typically developing controls participated. A behavioral task measuring attentional shifting within and across multiple dimensions (auditory, linguistic, and visual) was employed. Demands on attentional shifting were increased based on input dimension (low load: staying within dimension; medium load: shifting between 2 dimensions; and high load: shifting among 3 dimensions). Results Compared to controls, the group with SLI made more erroneous responses and exhibited longer response times. Although both groups' error rates were similarly affected by shifting compared to nonshifting trials, their response speed was not. The group with SLI exhibited a larger comparative decrement to their response speed in the high-attentional load condition. Discussion When demands on attentional shifting increase, children with SLI struggle to shift their attention as efficiently to changing stimuli as their unimpaired peers. Potential implications for the assessment and treatment of this population are discussed.

Semantic processing in children with cochlear implants: Evidence from event-related potentials.

Introduction: Existing research has shown that children with significant hearing loss who use cochlear implants (CIs) perform worse than their hearing peers on behavioral measures of spoken language. The present study sought to examine how children with CIs process lexical-semantic incongruence, as indexed by electrophysiological evidence of the N400 effect. Method: Twelve children with CIs, aged between 6 and 9 years, participated in a spoken word-picture matching task while event-related potentials (ERPs) were recorded. To determine whether the N400 effect elicited in this group deviated from normal, independent samples t tests and analysis of variance (ANOVA) analyses were used to compare the results of children with CIs against those of a similarly aged typically hearing (TH) group (n = 30). Correlational analyses were also conducted within each group to gauge the degree to which the N400 effect related to behavioral measures of spoken language. Results: An N400 effect was elicited in both groups of CI and TH children. The amplitude and latency of the N400 effect did not differ significantly between groups. Despite the similarity in ERP responses, children with CIs scored significantly lower on behavioral measures of spoken word- and sentence-level comprehension. No significant correlations between ERP and behavioral measures were found, although there was a trending relationship between sentence-level spoken language comprehension and the TH group's N400 effect mean amplitude (p = .060). Conclusions: The results suggest that, at a neural level, children with CIs can process lexical-semantic incongruence, and that other underlying processes not measured by the N400 effect contribute to this population's spoken language difficulties.

Thinking Ahead: Incremental Language Processing is Associated with Receptive Language Abilities in Preschoolers with Autism Spectrum Disorder.

In typical development, listeners can use semantic content of verbs to facilitate incremental language processing-a skill that is associated with existing language skills. Studies of children with ASD have not identified an association between incremental language processing in semantically-constraining contexts and language skills, perhaps because participants were adolescents and/or children with strong language skills. This study examined incremental language processing and receptive language in young children with ASD with a range of language skills. Children showed a head start when presented with semantically-constraining verbs (e.g., Read the book) compared to neutral verbs (e.g., Find the book). Children with weaker receptive language showed a smaller head start than children with stronger receptive language skills, suggesting continuity between typical development and ASD.

Communication interventions for autism spectrum disorder in minimally verbal children.

BACKGROUND: Autism spectrum disorder (ASD) has an estimated prevalence of around 1.7% of the population. People with ASD often also have language difficulties, and about 25% to 30% of children with ASD either fail to develop functional language or are minimally verbal. The ability to communicate effectively is an essential life skill, and difficulties with communication can have a range of adverse outcomes, including poorer academic achievement, behavioural difficulties and reduced quality of life. Historically, most studies have investigated communication interventions for ASD in verbal children. We cannot assume the same interventions will work for minimally verbal children with ASD. OBJECTIVES: To assess the effects of communication interventions for ASD in minimally verbal children. SEARCH METHODS: We searched CENTRAL, MEDLINE and Embase as well as 12 other databases and three trials registers in November 2017. We also checked the reference lists of all included studies and relevant reviews, contacting experts in the field as well as authors of identified studies about other potentially relevant ongoing and unpublished studies. SELECTION CRITERIA: Randomised controlled trials (RCTs) of communication-focused interventions for children (under 12 years of age) diagnosed with ASD and who are minimally verbal (fewer than 30 functional words or unable to use speech alone to communicate), compared with no treatment, wait-list control or treatment as usual. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. MAIN RESULTS: This review includes two RCTs (154 children aged 32 months to 11 years) of communication interventions for ASD in minimally verbal children compared with a control group (treatment as usual). One RCT used a verbally based intervention (focused playtime intervention; FPI) administered by parents in the home, whereas the other used an alternative and augmentative communication (AAC) intervention (Picture Exchange Communication System; PECS) administered by teachers in a school setting.The FPI study took place in the USA and included 70 participants (64 boys) aged 32 to 82 months who were minimally verbal and had received a diagnosis of ASD. This intervention focused on developing coordinated toy play between child and parent. Participants received 12 in-home parent training sessions for 90 minutes per session for 12 weeks, and they were also invited to attend parent advocacy coaching sessions. This study was funded by the National Institute of Child Health and Human Development, the MIND Institute Research Program and a Professional Staff Congress-City University of New York grant. The PECS study included 84 minimally verbal participants (73 boys) aged 4 to 11 years who had a formal diagnosis of ASD and who were not using PECS beyond phase 1 at baseline. All children attended autism-specific classes or units, and most classes had a child to adult ratio of 2:1. Teachers and parents received PECS training (two-day workshop). PECS consultants also conducted six half-day consultations with each class once per month over five months. This study took place in the UK and was funded by the Three Guineas Trust.Both included studies had high or unclear risk of bias in at least four of the seven 'Risk of bias' categories, with a lack of blinding for participants and personnel being the most problematic area. Using the GRADE approach, we rated the overall quality of the evidence as very low due to risk of bias, imprecision (small sample sizes and wide confidence intervals) and because there was only one trial identified per type of intervention (i.e. verbally based or AAC).Both studies focused primarily on communication outcomes (verbal and non-verbal). One of the studies also collected information on social communication. The FPI study found no significant improvement in spoken communication, measured using the expressive language domain of the Mullen Scale of Early Learning expressive language, at postintervention. However, this study found that children with lower expressive language at baseline (less than 11.3 months age-equivalent) improved more than children with better expressive language and that the intervention produced expressive language gains in some children. The PECS study found that children enrolled in the AAC intervention were significantly more likely to use verbal initiations and PECS symbols immediately postintervention; however, gains were not maintained 10 months later. There was no evidence that AAC improved frequency of speech, verbal expressive vocabulary or children's social communication or pragmatic language immediately postintervention. Overall, neither of the interventions (PECS or FPI) resulted in maintained improvements in spoken or non-verbal communication in most children.Neither study collected information on adverse events, other communication skills, quality of life or behavioural outcomes. AUTHORS' CONCLUSIONS: There is limited evidence that verbally based and ACC interventions improve spoken and non-verbal communication in minimally verbal children with ASD. A substantial number of studies have investigated communication interventions for minimally verbal children with ASD, yet only two studies met inclusion criteria for this review, and we considered the overall quality of the evidence to be very low. In the study that used an AAC intervention, there were significant gains in frequency of PECS use and verbal and non-verbal initiations, but not in expressive vocabulary or social communication immediately postintervention. In the study that investigated a verbally based intervention, there were no significant gains in expressive language postintervention, but children with lower expressive language at the beginning of the study improved more than those with better expressive language at baseline. Neither study investigated adverse events, other communication skills, quality of life or behavioural outcomes. Future RCTs that compare two interventions and include a control group will allow us to better understand treatment effects in the context of spontaneous maturation and will allow further comparison of different interventions as well as the investigation of moderating factors.

Effect of maternal pre-pregnancy underweight and average gestational weight gain on physical growth and intellectual development of early school-aged children.

The aim of this study was to assess the effect of low maternal weight at pre-pregnancy and the average gestational weight gain on undernourished children and their intellectual development. From October 2012 to September 2013, we followed 1744 offspring of women who participated in a trial conducted from 2002 to 2006. Pregnant women recruited in the original trial could receive three prenatal health checks for free, at which maternal weight and height were measured. WISC-IV was used to estimate the intellectual development of children. Weight and height of both pregnant women and children were measured by trained anthropometrists using standard procedures. Having low maternal weight at pre-pregnancy was associated with an increased risk of undernutrition amongst children (underweight: OR = 2.02, 95%CI: 1.14-3.56, thinness: OR = 2.79, 95%CI: 1.50-5.17) and a decrease in verbal comprehension index (-2.70 points, 95%CI: -4.95-0.44) of children. The effect of average gestational weight gain on occurrences of underweight children (OR = 0.08, 95%CI: 0.01-0.55) was also found. We identified the effect of maternal pre-pregnancy underweight on impairment of the separate intellectual domains (verbal comprehension index) and increasing occurrence of undernourished children. Average gestational weight gain was positively associated with a decreased prevalence of underweight children but not with the intellectual development of children in rural China.

Typical vs. atypical: Combining auditory Gestalt perception and acoustic analysis of early vocalisations in Rett syndrome.

BACKGROUND: Early speech-language development of individuals with Rett syndrome (RTT) has been repeatedly characterised by a co-occurrence of apparently typical and atypical vocalisations. AIMS: To describe specific features of this intermittent character of typical versus atypical early RTT-associated vocalisations by combining auditory Gestalt perception and acoustic vocalisation analysis. METHODS AND PROCEDURES: We extracted N = 363 (pre-)linguistic vocalisations from home video recordings of an infant later diagnosed with RTT. In a listening experiment, all vocalisations were assessed for (a)typicality by five experts on early human development. Listeners' auditory concepts of (a)typicality were investigated in context of a comprehensive set of acoustic time-, spectral- and/or energy-related higher-order features extracted from the vocalisations. OUTCOMES AND RESULTS: More than half of the vocalisations were rated as 'atypical' by at least one listener. Atypicality was mainly related to the auditory attribute 'timbre', and to prosodic, spectral, and voice quality features in the acoustic domain. CONCLUSIONS AND IMPLICATIONS: Knowledge gained in our study shall contribute to the generation of an objective model of early vocalisation atypicality. Such a model might be used for increasing caregivers' and healthcare professionals' sensitivity to identify atypical vocalisation patterns, or even for a probabilistic approach to automatically detect RTT based on early vocalisations.

Reading comprehension difficulties in children with rolandic epilepsy.

AIM: Difficulties in reading comprehension can arise from either word reading or listening comprehension difficulties, or a combination of the two. We sought to determine whether children with rolandic epilepsy had poor reading comprehension relative to typically developing comparison children, and whether such difficulties were associated with word reading and/or general language comprehension difficulties. METHOD: In this cross-sectional study, children with rolandic epilepsy (n=25; 16 males, 9 females; mean age 9y 1mo, SD 1y 7mo) and a comparison group (n=39; 25 males, 14 females; mean age 9y 1mo, SD 1y 3mo) completed assessments of reading comprehension, listening comprehension, word/non-word reading, speech articulation, and Non-verbal IQ. RESULTS: Reading comprehension and word reading were worse in children with rolandic epilepsy (F1,61 =6.89, p=0.011, ηp2=0.10 and F1,61 =6.84, p=0.011, ηp2=0.10 respectively), with listening comprehension being marginal (F1,61 =3.81, p=0.055, ηp2=0.06). Word reading and listening comprehension made large and independent contributions to reading comprehension, explaining 70% of the variance. INTERPRETATION: Children with rolandic epilepsy may be at risk of reading comprehension difficulties. Thorough assessment of individual children is required to ascertain whether the difficulties lie with decoding text, or with general comprehension skills, or both. WHAT THIS PAPER ADDS: Children with rolandic epilepsy may be at risk of poor reading comprehension. This was related to poor word reading, poor listening comprehension, or both. Reading comprehension interventions should be tailored to the profile of difficulties.

Anodal transcranial direct current stimulation over left inferior frontal gyrus enhances sentence comprehension.

We tested the possibility of enhancing natural language comprehension through the application of anodal tDCS (a-tDCS) over the left inferior frontal gyrus, a key region for verbal short-term memory and language comprehension. We designed a between subjects sham- and task-controlled study. During tDCS stimulation, participants performed a sentence to picture matching task in which targets were sentences with different load on short-term memory. Regardless of load on short-term memory, the Anodal group performed significantly better than the Sham group, thus providing evidence that a-tDCS over LIFG enhances natural language comprehension. To our knowledge, we apply for the first time tDCS to boost sentence comprehension. This result is of special interest also from a clinical perspective: applying a-tDCS in patients manifesting problems at the sentence level due to brain damage could enhance the effects of behavioral rehabilitation procedures aimed to improve language comprehension.

Does lexical stress influence 17-month-olds' mapping of verbs and nouns?

English-learning infants attend to lexical stress when learning new words. Attention to lexical stress might be beneficial for word learning by providing an indication of the grammatical class of that word. English disyllabic nouns commonly have trochaic (strong-weak) stress, whereas English disyllabic verbs commonly have iambic (weak-strong) stress. We explored whether 17-month-old infants use word stress to resolve an ambiguous labeling event where objects and actions are equally plausible referents. Infants were habituated to 2 words paired with 2 objects, with each object performing a distinct path action. They were subsequently tested on (a) a change in object but not path action or (b) a change in path action but not the object. When infants were taught verb-friendly iambic labels, their looking times increased both when the action switched and when the object switched. Infants who were taught noun-friendly trochaic labels demonstrated an increase in looking time only when the object switched. These results demonstrate that in ambiguous labeling events infants map iambic labels to both actions and objects, and trochaic labels to the objects but not to the actions, suggesting a bias for words with trochaic stress to refer to objects. Seventeen-month-old infants can use trochaic lexical stress to guide their word learning in ambiguous situations, but iambic stress cues may not preferentially guide infants' mappings of actions or objects. (PsycINFO Database Record

Is children's listening effort in background noise influenced by the speaker's voice quality?

The present study aims at exploring the influence of voice quality on listening effort in children performing a language comprehension test with sentences of increasing difficulty. Listening effort is explored in relation to gender ( = cisgender). The study has a between-groups design. Ninety-three mainstreamed children aged 8;2 to 9;3 with typical language development participated. The children were randomly assigned to two groups (n = 46/47) with equal allocation of boys and girls and for the analysis to four groups depending of gender and voice condition. Working memory capacity and executive functions were tested in quiet. A digital version of a language comprehension test (the TROG-2) was used to measure the effect of voice quality on listening effort, measured as response time in a forced-choice paradigm. The groups listened to sentences through recordings of the same female voice, one group with a typical voice and one with a dysphonic voice, both in competing multi-talker babble noise. Response times were logged after a time buffer between the sentence-ending and indication of response. There was a significant increase in response times with increased task difficulty and response times between the two voice conditions differed significantly. The girls in the dysphonic condition were slower with increasing task difficulty. A dysphonic voice clearly adds to the noise burden and listening effort is greater in girls than in boys when the teacher speaks with dysphonic voice in a noisy background. These findings might mirror gender differences as for coping strategies in challenging contexts and have important implications for education.

Sensitivity of expressive linguistic domains to surgery age and audibility of speech in preschoolers with cochlear implants.

OBJECTIVES: To determine whether relative delays among domains exist in the conversational use of vocabulary, syntax, and morphology by children with cochlear implants (CIs) and whether these were differentially affected by age of implantation (AOI) and the audibility of speech. METHODS: Participants in this short-term longitudinal study were 126 children with AOI of 6-38 months and a matched group of 30 children without hearing loss. Language samples of the same children at ages 3.5 and 4.5 were analyzed for the breadth of vocabulary and bound morphemes used, and sentence length. RESULTS: At both test ages, expressive language domains were delayed equally. Higher performance across domains was independently associated with younger AOI and better pre-implant-aided thresholds. No domain was affected differently by very early implantation, but bound morpheme breadth was associated with better CI-aided thresholds. Between 63 and 78% of children with AOI of 6-11 months scored close to hearing age-mates by 4.5, a level achieved by fewer than 25% of those with AOI of 19-24 months or later ages. DISCUSSION: Previous studies indicated greater language delays in the areas of morphology and syntax than those of vocabulary, with the earliest ages of implantation conferring the greatest benefit to those domains. The current design addressed inconsistency across studies in modes of communication used, presence/absence of other disabilities, and differences in language domains chosen as outcome measures. CONCLUSIONS: Linguistic domains benefitted equally from early implantation, regardless of the duration of auditory stimulation. Better pre-CI-aided hearing often compensated for later AOI. Bound morpheme use was greater with better CI-aided thresholds.

Spoken language and everyday functioning in 5-year-old children using hearing aids or cochlear implants.

OBJECTIVE: This study investigated the factors influencing 5-year language, speech and everyday functioning of children with congenital hearing loss. DESIGN: Standardised tests including PLS-4, PPVT-4 and DEAP were directly administered to children. Parent reports on language (CDI) and everyday functioning (PEACH) were collected. Regression analyses were conducted to examine the influence of a range of demographic variables on outcomes. STUDY SAMPLE: Participants were 339 children enrolled in the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study. RESULTS: Children's average receptive and expressive language scores were approximately 1 SD below the mean of typically developing children, and scores on speech production and everyday functioning were more than 1 SD below. Regression models accounted for 70-23% of variance in scores across different tests. Earlier CI switch-on and higher non-verbal ability were associated with better outcomes in most domains. Earlier HA fitting and use of oral communication were associated with better outcomes on directly administered language assessments. Severity of hearing loss and maternal education influenced outcomes of children with HAs. The presence of additional disabilities affected outcomes of children with CIs. CONCLUSIONS: The findings provide strong evidence for the benefits of early HA fitting and early CI for improving children's outcomes.

Intensive Treatment for Persisting Rhotic Distortions: A Case Series.

PURPOSE: The study explored changes in accuracy of American English rhotics as a result of an intensive 1-week therapy program for adolescents and young adults with residual speech sound errors that had not resolved with previous therapy. METHOD: Four case reports are presented of individuals aged 13, 17, 21, and 22 years with residual /ɹ/ distortions. Each participant attended a 1-week intensive program consisting of pretreatment assessments, 14 hr of therapy, and posttreatment assessment. Treatment sessions included structured motor-based practice, ultrasound visual feedback of the tongue, and auditory speech perception training. To assess generalization, untreated words and sentences with rhotics were recorded before and after therapy; these were rated by listeners who were blind to when the recordings were taken. RESULTS: All participants showed measurable and statistically significant improvement in speech sound accuracy. Averaged across the 4 participants, rhotic accuracy at the word level improved from 35% to 83%. At the sentence level, rhotic accuracy increased from 11% pretreatment to 66% posttreatment in 1 week. CONCLUSION: The promise of an intensive treatment program that includes motor-based practice, biofeedback, and auditory perception training is illustrated by the case presentations in which substantial improvements in speech sound accuracy were observed. SUPPLEMENTAL MATERIALS: https://doi.org/10.23641/asha.5561254.

Language impairment and comorbid vulnerabilities among young people in custody.

BACKGROUND: While the prevalence of language and communication difficulties among young people in custody is well established, holistic understanding of the complexity and co-occurrence of additional vulnerabilities among this population are rare. METHODS: Ninety-three young people in a young offenders institution in England were assessed using the Comprehensive Health Assessment Tool, the Test of Word Knowledge, and a range of additional assessments of communication, cognition, and neurodevelopmental difficulties. RESULTS: Forty-seven percent of the young people demonstrated an aspect of language skills significantly below the population average, with more than one in four identified as having impairment. Only one in four of those with an impairment had previously accessed speech and language services. Language needs were associated with difficulties with social communication and nonverbal cognition, as well as higher risk of self-harm and substance misuse. CONCLUSIONS: Earlier identification of language difficulties requires routine assessment of young people at risk of engagement in offending behavior. Where language difficulties are identified, holistic assessments of needs should be undertaken. There is a need for speech and language therapy provision within youth justice services, as well as in other services accessed by young people at risk of engagement in offending.

Efficacy of Electropalatography for Treating Misarticulation of /r/.

PURPOSE: The purpose of the present study was to document the efficacy of electropalatography (EPG) for the treatment of rhotic errors in school-age children. Despite a growing body of literature using EPG for the treatment of speech sound errors, there is little systematic evidence about the relative efficacy of EPG for rhotic errors. METHOD: Participants were 5 English-speaking children aged 6;10 to 9;10, who produced /r/ at the word level with < 30% accuracy but otherwise showed typical speech, language, and hearing abilities. Therapy was delivered in twice-weekly 30-min sessions for 8 weeks. RESULTS: Four out of 5 participants were successful in achieving perceptually and acoustically accurate /r/ productions during within-treatment trials. Two participants demonstrated generalization of /r/ productions to nontreated targets, per blinded listener ratings. CONCLUSIONS: The present findings support the hypothesis that EPG can improve production accuracy in some children with rhotic errors. However, the utility of EPG is likely to remain variable across individuals. For rhotics, EPG training emphasizes one possible tongue configuration consistent with accurate rhotic production (lateral tongue contact). Although some speakers respond well to this cue, the narrow focus may limit lingual exploration of other acceptable tongue shapes known to facilitate rhotic productions.

Assessing the Importance of Lexical Tone Contour to Sentence Perception in Mandarin-Speaking Children With Normal Hearing.

Purpose: The aim of the present study was to evaluate the influence of lexical tone contour and age on sentence perception in quiet and in noise conditions in Mandarin-speaking children ages 7 to 11 years with normal hearing. Method: Test materials were synthesized Mandarin sentences, each word with a manipulated lexical contour, that is, normal contour, flat contour, or a tone contour randomly selected from the four Mandarin lexical tone contours. A convenience sample of 75 Mandarin-speaking participants with normal hearing, ages 7, 9, and 11 years (25 participants in each age group), was selected. Participants were asked to repeat the synthesized speech in quiet and in speech spectrum-shaped noise at 0 dB signal-to-noise ratio. Results: In quiet, sentence recognition by the 11-year-old children was similar to that of adults, and misrepresented lexical tone contours did not have a detrimental effect. However, the performance of children ages 9 and 7 years was significantly poorer. The performance of all three age groups, especially the younger children, declined significantly in noise. Conclusions: The present research suggests that lexical tone contour plays an important role in Mandarin sentence recognition, and misrepresented tone contours result in greater difficulty in sentence recognition in younger children. These results imply that maturation and/or language use experience play a role in the processing of tone contours for Mandarin speech understanding, particularly in noise.

Variable Practice to Enhance Speech Learning in Ultrasound Biofeedback Treatment for Childhood Apraxia of Speech: A Single Case Experimental Study.

PURPOSE: The purpose of this study was to evaluate the role of practice variability, through prosodic variation during speech sound training, in biofeedback treatment for children with childhood apraxia of speech. It was hypothesized that variable practice would facilitate speech sound learning. METHOD: Six children ages 8-16 years with persisting speech sound errors due to childhood apraxia of speech participated in a single-subject experimental design. For each participant, 2 speech sound targets were treated with ultrasound visual feedback training: one with prosodic variation (i.e., practicing sound targets in words and phrases spoken fast, slow, loud, as a question, command, and declarative), and one without prosodic variation. Each target was treated for half of the 1-hr session for 14 treatment sessions. RESULTS: As measured by standardized effect sizes, all participants showed greater change on generalization probes for sound targets treated under the prosodic variation condition with mean effect sizes (d2) of 14.5 for targets treated with prosodic variation and 8.3 for targets treated without prosodic variation. The average increase in generalization scores was 38% in the prosodic variation condition compared to 31% without. CONCLUSIONS: Ultrasound visual feedback may facilitate speech sound learning and learning may be enhanced by treating speech sounds with explicit prosodic variation. SUPPLEMENTAL MATERIALS: https://doi.org/10.23641/asha.5150119.

The Nature of Error Consistency in Individuals With Acquired Apraxia of Speech and Aphasia.

PURPOSE: The primary characteristics used to define acquired apraxia of speech (AOS) have evolved to better reflect a disorder of motor planning/programming. However, there is debate regarding the feature of relatively consistent error location and type. METHOD: Ten individuals with acquired AOS and aphasia and 11 individuals with aphasia without AOS participated in this study. In the context of a 2-group experimental design, error consistency was examined via 5 repetitions of 30 multisyllabic words. The influence of error rate, severity of impairment, and stimulus presentation condition (blocked vs. random) on error consistency was also explored, as well as between-groups differences in the types of errors produced. RESULTS: Groups performed similarly on consistency of error location; however, adults with AOS demonstrated greater variability of error type in a blocked presentation condition only. Stimulus presentation condition, error rate, and severity of impairment did not influence error consistency in either group. Groups differed in the production of phonetic errors (e.g., sound distortions) but not phonemic errors. CONCLUSIONS: Overall, findings do not support relatively consistent errors as a differentiating characteristic of AOS.

Syntactic Complexity and Frequency in the Neurocognitive Language System.

Prominent neurobiological models of language follow the widely accepted assumption that language comprehension requires two principal mechanisms: a lexicon storing the sound-to-meaning mapping of words, primarily involving bilateral temporal regions, and a combinatorial processor for syntactically structured items, such as phrases and sentences, localized in a left-lateralized network linking left inferior frontal gyrus (LIFG) and posterior temporal areas. However, recent research showing that the processing of simple phrasal sequences may engage only bilateral temporal areas, together with the claims of distributional approaches to grammar, raise the question of whether frequent phrases are stored alongside individual words in temporal areas. In this fMRI study, we varied the frequency of words and of short and long phrases in English. If frequent phrases are indeed stored, then only less frequent items should generate selective left frontotemporal activation, because memory traces for such items would be weaker or not available in temporal cortex. Complementary univariate and multivariate analyses revealed that, overall, simple words (verbs) and long phrases engaged LIFG and temporal areas, whereas short phrases engaged bilateral temporal areas, suggesting that syntactic complexity is a key factor for LIFG activation. Although we found a robust frequency effect for words in temporal areas, no frequency effects were found for the two phrasal conditions. These findings support the conclusion that long and short phrases are analyzed, respectively, in the left frontal network and in a bilateral temporal network but are not retrieved from memory in the same way as simple words during spoken language comprehension.