Biology subjects

Crinion, J.

Publications and source records attributed to Crinion, J..

4 recordsLinked to original sources

bioRxiv2021

Mapping language and non-language cognitive deficits in post-stroke anomic aphasia

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. Despite this, people with aphasia (PWA) are rarely tested on assessments of higher order cognitive functions, making it difficult for studies to associate these functions with a consistent lesion correlate. Contrary to classic models of speech and language, cumulative evidence shows that Brocas area and surrounding regions in the left inferior frontal cortex (LIFC) are involved in, but not specific to, speech production - suggesting that these regions may be involved in higher-level cognitive functions that support language production. A better understanding of language processing in the context of other domain general cognitive functions is essential for improving aphasia treatments. This study aimed to explore the brain-behaviour relationships between tests of individual cognitive skill and language abilities in people with post-stroke aphasia, with a focus on language production deficits and their associated lesion correlates. We predicted our analysis would reveal a latent (non-language specific) cognitive component, that would be driven by damage to LIFC. We analysed the behavioural and neural correlates of an extensive battery of language and non-language cognitive tests in a sample of thirty-six adults with long-term speech production deficits from post-stroke aphasia. All participants were anomic, with relatively intact speech comprehension and no apraxia of speech. The behavioural variables were analysed using Principal Component Analysis and their neural correlates were estimated using Voxel-Based Correlational Morphology. A significant number of anomic adults showed impaired performance on tests of non-language specific cognitive function. The variance underlying behavioural performance was best captured by four orthogonal components, two higher-order cognitive components (executive functions and verbal working memory) and two linguistic processing components (phonology and semantics). Brain-behaviour relationships revealed separable neural correlates for each component in line with previous studies and an executive functions correlate in the left inferior frontal cortex (LIFC). Our findings suggest that in adults with chronic post-stroke language production deficits (anomia), higher-level cognitive functions explain more of the variance in language function than classical models of the condition imply. Additionally, lesions to the LIFC, including Brocas area, were associated with executive (dys)function, independent of language abilities, suggesting that lesions to this area are associated with non-language specific higher-level cognitive functions that support speech production. These findings support contemporary models of speech production that place language processing within the context of domain-general perception, action and conceptual knowledge.

neuroscience↗

bioRxiv2021

Cued Naming and the left inferior frontal cortex

Clinical studies have shown that naming can be behaviorally facilitated by priming, e.g., phonemic cues reduce anomia. Rehabilitation of language is argued to rely upon the same processes of priming in healthy speakers. Here we show, in healthy older adults, the immediate facilitatory behavioral and neural priming elicited by phonemic cues presented during an fMRI experiment of overt naming; thus, bridging the gap between lesion and neuroimaging studies. Four types of auditory cues were presented concurrently with an object picture (e.g., cat): (i) word (i.e., the target name (/kat/), (ii) initial phoneme segment (e.g., /ka/), (iii) final phoneme segment (/at/), or (iv) acoustic (noise) control cue. Naming was significantly faster with word, initial and final phonemic cues compared to noise; and word and initial cues compared to final cues, with no difference between word and initial cues. A neural priming effect - a significant decrease in neural activity - was observed in the left inferior frontal cortex (LIFC, pars triangularis, BA45) and the anterior insula bilaterally consistent with theories of primed articulatory encoding and post-lexical selection. The reverse contrast revealed increased activation in left posterior dorsal supramarginal gyrus for word cues that, we argue, may reflect integration of semantic and phonology processing during word rather than phonemic conditions. Taken together, these data from unimpaired speakers identified nodes within the naming network affected by phonemic cues. Activity within these regions may act as a possible biomarker to index anomic individuals responsiveness to phonemically cued anomia treatment.

neuroscience↗

bioRxiv2021

Lesion site and therapy time predict responses to a therapy for anomia after stroke: a prognostic model development study

BACKGROUNDStroke is a leading cause of disability, and language impairments (aphasia) after stroke are both common and particularly feared. Most stroke survivors with aphasia exhibit anomia (difficulties with naming common objects), but while many therapeutic interventions for anomia have been proposed, treatment effects are typically much larger in some patients than others. Here, we asked whether that variation might be more systematic, and even predictable, than previously thought. METHODS18 patients, each at least 6 months after left hemisphere stroke, engaged in a computerised treatment for their anomia over a 6 week period. Using only: (a) the patients initial accuracy when naming (to-be) trained items; (b) the hours of therapy that they devoted to the therapy; and (c) whole-brain lesion location data, derived from structural MRI; we developed Partial Least Squares regression models to predict the patients improvements on treated items, and tested them in cross-validation. RESULTSSomewhat surprisingly, the best model included only lesion location data and the hours of therapy undertaken. In cross-validation, this model significantly out-performed the null model, in which the prediction for each patient was simply the mean treatment effect of the group. This model also made promisingly accurate predictions in absolute terms: the correlation between empirical and predicted treatment response was 0.62 (95%CI: 0.27, 0.95). DISCUSSIONOur results indicate that individuals variation in response to anomia treatment are, at least somewhat, systematic and predictable, from the interaction between where and how much lesion damage they have suffered, and the time they devoted to the therapy.

neuroscience↗

bioRxiv2021

Modulating the left inferior frontal cortex by task domain, cognitive challenge and tDCS

The left inferior frontal cortex (LIFC) is a key region for spoken language processing, but its neurocognitive architecture remains controversial. Here we assess the domain-generality vs. domain-specificity of the LIFC from behavioural, functional neuroimaging and neuromodulation data. Using concurrent fMRI and transcranial direct current stimulation (tDCS) delivered to the LIFC, we investigated how brain activity and behavioural performance are modulated by task domain (naming vs. non-naming), cognitive challenge (low vs. high), and tDCS (anodal vs. sham). The data revealed: (1) co-existence of neural signatures both common and distinct across tasks within the LIFC; (2) domain-preferential effects of task (naming); (3) significant tDCS modulations of activity in a LIFC sub-region selectively during high-challenge naming. The presence of both domain-specific and domain-general signals, and the existence of a gradient of activation where naming relied more on sub-regions within the LIFC, may help reconcile both perspectives on spoken language processing.

neuroscience↗