Children's computation of complex linguistic forms: a study of frequency and imageability effects.

This study investigates the storage vs. composition of inflected forms in typically-developing children. Children aged 8-12 were tested on the production of regular and irregular past-tense forms. Storage (vs. composition) was examined by probing for past-tense frequency effects and imageability effects--both of which are diagnostic tests for storage--while controlling for a number of confounding factors. We also examined sex as a factor. Irregular inflected forms, which must depend on stored representations, always showed evidence of storage (frequency and/or imageability effects), not only across all children, but also separately in both sexes. In contrast, for regular forms, which could be either stored or composed, only girls showed evidence of storage. This pattern is similar to that found in previously-acquired adult data from the same task, with the notable exception that development affects which factors influence the storage of regulars in females: imageability plays a larger role in girls, and frequency in women. Overall, the results suggest that irregular inflected forms are always stored (in children and adults, and in both sexes), whereas regulars can be either composed or stored, with their storage a function of various item- and subject-level factors

The neurocognition of developmental disorders of language

Developmental disorders of language include developmental language disorder, motor-speech disorders such as articulation disorder and stuttering, and dyslexia. These disorders have been explained by various accounts, which generally focus on their behavioral rather than neural characteristics, their processing rather than learning impairments, and each disorder separately rather than together, despite their commonalities and comorbidities. Here we update and review a unifying neurocognitive account, the Procedural circuit Deficit Hypothesis (PDH). The PDH posits that abnormalities of brain structures underlying procedural memory (learning and memory that relies on the basal ganglia and associated circuitry) can explain numerous brain and behavioral characteristics, across learning and processing, in multiple disorders, including both commonalities and differences. We describe procedural memory, examine its role in multiple aspects of language, and then present the PDH and relevant evidence across language-related disorders. The PDH has substantial explanatory power, and both basic research and translational implications

The Auditory Comprehension of Unaccusative Verbs in Aphasia

Some persons with aphasia, particularly those diagnosed with a Broca’s aphasia, exhibit a delayed time course of lexical activation in canonically ordered S-V-O sentences (Ferrill et al., 2012) and delayed re-activation of displaced arguments in sentences that contain syntactic dependencies (Love et al., 2008). These patterns support the Delayed Lexical Activation (DLA) hypothesis: Lexical activation is delayed relative to the normal case, and thus lexical activation and syntactic operations are de-synchronized; that is, lexical access is too slow for normally fast-acting syntactic operations. This delay in lexical access leads to what appear to be syntactic comprehension deficits in aphasia. In the current study we further examined lexical activation during sentence comprehension in persons with aphasia by using unaccusative verbs. Unaccusative verbs are a type of intransitive verb with a single argument that is base generated in object position and displaced to the surface subject position, leaving behind a copy or trace (‘gap’) of the movement (see, for example, Burzio, 1986), as in: 1. The girl vanished Thus there is a syntactic dependency between the two positions. When encountering sentences that contain syntactic dependencies (e.g., object relatives, Wh-questions) neurologically unimpaired individuals immediately reactivate the displaced argument at the gap (Shapiro et al., 1999; Love et al., 2008). In contrast to this immediate reactivation, prior findings indicate that neurologically unimpaired individuals do not reactivate the displaced argument in similar sentences with unaccusative verbs until 750ms downstream from the gap (Friedmann et al., 2008). This built-in delay observed with unaccusative verbs in neurologically healthy participants provides a unique opportunity to further examine lexical delays in individuals with Broca’s aphasia. Importantly, individuals with Broca’s aphasia may have unaccusative verb deficits. Previous research has found that persons with aphasia have difficulty producing unaccusative verbs. Offline truth-value judgment tasks with intransitive sentences containing unaccusative verbs do not reveal comprehension deficits (Lee & Thompson, 2004). However, in a sentence-picture matching task, McAllister et al. (2009) found lower accuracy for intransitive sentences that contained unaccusative verbs than transitive sentences. We entertain the following hypothesis: The delayed lexical access routines better synchronize with the delay of reactivating the argument of unaccusatives, suggesting that individuals with Broca’s aphasia should evince a pattern like that of unimpaired individuals. Alternatively, participants with Broca’s aphasia might show activation even further downstream from the gap, given that in other sentence constructions containing syntactic dependencies they exhibit a delayed pattern of reactivation compared to neurologically unimpaired individuals

Comprehension of Who and Which-NP questions: Which Account do the Data Support?

This study investigated the comprehension of various types of Wh-questions in unimpaired adults and those with Broca’s aphasia. Using an eye tracking-while listening method, we examined four specific hypotheses. Our initial results for our healthy controls revealed offline support for a Word Order Hypothesis – object-extracted Who and Which-NP questions took longer to resolve than subject-extracted versions. Our results using eye gaze data, however, revealed support for a Retrieval Hypothesis – Which-NP questions that contain more specific information yielded fewer looks to the correct referent than their Who-question counterparts. These patterns set the stage for our ongoing aphasia study

The impact of sound field systems on learning and attention in elementary school classrooms

Purpose: An evaluation of the installation and use of sound field systems (SFS) was carried out to investigate their impact on teaching and learning in elementary school classrooms. Methods: The evaluation included acoustic surveys of classrooms, questionnaire surveys of students and teachers and experimental testing of students with and without the use of SFS. Students ’ perceptions of classroom environments and objective data evaluating change in performance on cognitive and academic assessments with amplification over a six month period are reported. Results: Teachers were positive about the use of SFS in improving children’s listening and attention to verbal instructions. Over time students in amplified classrooms did not differ from those in nonamplified classrooms in their reports of listening conditions, nor did their performance differ in measures of numeracy, reading or spelling. Use of SFS in the classrooms resulted in significantly larger gains in performance in the number of correct items on the nonverbal measure of speed of processing and the measure of listening comprehension. Analysis controlling for classroom acoustics indicated that students ’ listening comprehension score

Structure-function correspondences in Broca’s aphasia: Evidence from MRI and comprehension of verb phrase ellipsis constructions

We describe an effort to map lesion to behavior by studying the comprehension of complex VP-Ellipsis constructions (e.g., The policeman defended the child, and the dedicated fireman did___ too…) in participants with Broca‟s aphasia. We quantified the lesions of our individual participants using cytoarchitectonic probability maps of the human brain. We found that our Broca participants evinced delayed priming of the object in the ellipsis clause, while off-line comprehension was largely spared. Structure-function analyses revealed that lesions in both temporal and frontal areas participated in the behavioral outcomes, though each region seems to have played a distinct role

Language abilities in children with autism and language impairment: using narrative as a additional source of clinical information

Autistic Spectrum Disorder (ASD) and Specific Language Impairment (SLI) are disorders of communication that are sometimes thought to show similar structural language difficulties. Recent research has even suggested that they might be aetiologically related. However, it may be that standardized language tasks are not sensitive enough to detect similarities and differences accurately. This study involved 26 Greek children with either ASD or SLI and compared them on standardized measures of structural and pragmatic language as well as using a structured narrative task. Children with ASD were more impaired on receptive but not expressive scores from standardized language tests. In contrast, narrative measures showed significantly poorer ASD performance in expressive skills involving wider story-telling skill and in some sentence-level skills, in particular referencing, compared to peers with SLI. ASD and SLI groups also showed different relationships between structural language and other measures. The data suggests that narrative is a useful tool for revealing qualitative differences in language between overlapping communication disorders both at the clinical and theoretical level, since it provides information that is lost in more formalized testing. This may be particularly true where norms are not available or testing is difficult

Learning and consolidation of new spoken words in autism spectrum disorder

Autism spectrum disorder (ASD) is characterized by rich heterogeneity in vocabulary knowledge and word knowledge that is not well accounted for by current cognitive theories. This study examines whether individual differences in vocabulary knowledge in ASD might be partly explained by a difficulty with consolidating newly learned spoken words and/or integrating them with existing knowledge. Nineteen boys with ASD and 19 typically developing (TD) boys matched on age and vocabulary knowledge showed similar improvements in recognition and recall of novel words (e.g. 'biscal') 24 hours after training, suggesting an intact ability to consolidate explicit knowledge of new spoken word forms. TD children showed competition effects for existing neighbors (e.g. 'biscuit') after 24 hours, suggesting that the new words had been integrated with existing knowledge over time. In contrast, children with ASD showed immediate competition effects that were not significant after 24 hours, suggesting a qualitative difference in the time course of lexical integration. These results are considered from the perspective of the dual-memory systems framework

The production of nominal and verbal inflection in an agglutinative language: evidence from Hungarian

The contrast between regular and irregular inflectional morphology has been useful in investigating the functional and neural architecture of language. However, most studies have examined the regular/irregular distinction in non-agglutinative Indo-European languages (primarily English) with relatively simple morphology. Additionally, the majority of research has focused on verbal rather than nominal inflectional morphology. The present study attempts to address these gaps by introducing both plural and past tense production tasks in Hungarian, an agglutinative non-Indo-European language with complex morphology. Here we report results on these tasks from healthy Hungarian native-speaking adults, in whom we examine regular and irregular nominal and verbal inflection in a within-subjects design. Regular and irregular nouns and verbs were stem on frequency, word length and phonological structure, and both accuracy and response times were acquired. The results revealed that the regular/irregular contrast yields similar patterns in Hungarian, for both nominal and verbal inflection, as in previous studies of non-agglutinative Indo-European languages: the production of irregular inflected forms was both less accurate and slower than of regular forms, both for plural and past-tense inflection. The results replicate and extend previous findings to an agglutinative language with complex morphology. Together with previous studies, the evidence suggests that the regular/irregular distinction yields a basic behavioral pattern that holds across language families and linguistic typologies. Finally, the study sets the stage for further research examining the neurocognitive substrates of regular and irregular morphology in an agglutinative non-Indo-European language