Mapping spoken language and cognitive deficits in post-stroke aphasia.

Aphasia is an acquired disorder caused by damage, most commonly due to stroke, to brain regions involved in speech and language. While language impairment is the defining symptom of aphasia, the co-occurrence of non-language cognitive deficits and their importance in predicting rehabilitation and recovery outcomes is well documented. However, people with aphasia (PWA) are rarely tested on higher-order cognitive functions, making it difficult for studies to associate these functions with a consistent lesion correlate. Broca's area is a particular brain region of interest that has long been implicated in speech and language production. Contrary to classic models of speech and language, cumulative evidence shows that Broca's area and surrounding regions in the left inferior frontal cortex (LIFC) are involved in, but not specific to, speech production. In this study we aimed to explore the brain-behaviour relationships between tests of cognitive skill and language abilities in thirty-six adults with long-term speech production deficits caused by post-stroke aphasia. Our findings suggest that non-linguistic cognitive functions, namely executive functions and verbal working memory, explain more of the behavioural variance in PWA than classical language models imply. Additionally, lesions to the LIFC, including Broca's area, were associated with non-linguistic executive (dys)function, suggesting that lesions to this area are associated with non-language-specific higher-order cognitive deficits in aphasia. Whether executive (dys)function - and its neural correlate in Broca's area - contributes directly to PWA's language production deficits or simply co-occurs with it, adding to communication difficulties, remains unclear. These findings support contemporary models of speech production that place language processing within the context of domain-general perception, action and conceptual knowledge. An understanding of the covariance between language and non-language deficits and their underlying neural correlates will inform better targeted aphasia treatment and outcomes.

Realisation of grammatical morphemes by children with phonological impairment.

The aim of this research was to explore how preschool-aged children with phonological impairment (PI) realise grammatical morphemes across different phonological contexts (i.e. singleton consonant, consonant cluster, syllable), conditions of finiteness and individual morpheme types. Factors accounting for children's realisation of grammatical morphemes were also examined. Eighty-seven Australian English-speaking preschoolers (aged 4-5 years) with PI completed the Children's Assessment of Morphophonology (CHAMP)-an elicited response task-in addition to standardised tests of speech and receptive language. The most challenging grammatical morphemes were finite morphemes (particularly past tense) and grammatical morphemes realised in consonant clusters. The ability to produce consonant clusters in single words significantly accounted for children's ability to realise grammatical morphemes, regardless of whether grammatical morphemes were realised in singleton, consonant cluster or syllable contexts. Realisation of grammatical morphemes by preschoolers with PI is influenced by phonological and morphological factors. The findings have implications regarding the assessment and differential diagnosis of preschoolers with concomitant phonological and language difficulties.

Cluster-Randomized Controlled Trial Evaluating the Effectiveness of Computer-Assisted Intervention Delivered by Educators for Children With Speech Sound Disorders.

Purpose: The aim was to evaluate the effectiveness of computer-assisted input-based intervention for children with speech sound disorders (SSD). Method: The Sound Start Study was a cluster-randomized controlled trial. Seventy-nine early childhood centers were invited to participate, 45 were recruited, and 1,205 parents and educators of 4- and 5-year-old children returned questionnaires. Children whose parents and educators had concerns about speech were assessed (n = 275); 132 children who were identified with phonological pattern-based errors underwent additional assessment. Children with SSD and no difficulties with receptive language or hearing, typical nonverbal intelligence, and English as their primary language were eligible; 123 were randomized into two groups (intervention n = 65; control n = 58), and 3 withdrew. The intervention group involved Phoneme Factory Sound Sorter software (Wren & Roulstone, 2013) administered by educators over 9 weeks; the control group involved typical classroom practices. Participants were reassessed twice by a speech-language pathologist who was unaware of the initial assessment and intervention conditions. Results: For the primary outcome variable (percentage of consonants correct), the significant mean change from pre- to postintervention for the intervention group (mean change = +6.15, p < .001) was comparable in magnitude to the significant change for the control group (mean change = +5.43, p < .001) with a small between-groups effect size for change (Cohen's d = 0.08). Similar results occurred for measures of emergent literacy, phonological processing, participation, and well-being. Conclusion: Computer-assisted input-based intervention administered by educators did not result in greater improvement than typical classroom practices.