Language distance modulates cognitive control in bilinguals

Linguistic processes in the bilingual brain are partially shared across languages, and the degree of neural overlap between the languages is influenced by several factors, including the age of acquisition, relative language proficiency, and immersion. There is limited evidence on the role of linguistic distance on the performance of the language control as well as domain-general cognitive control systems. The present study aims at exploring whether being bilingual in close and distant language pairs (CLP and DLP) influences language control and domain-general cognitive processes. We recruited two groups of DLP (Persian–English) and CLP (French–English) bilinguals. Subjects performed language nonswitching and switching picture-naming tasks and a nonlinguistic switching task while EEG data were recorded. Behaviorally, CLP bilinguals showed a lower cognitive cost than DLP bilinguals, reflected in faster reaction times both in language switching (compared to nonswitching) and nonlinguistic switching. ERPs showed differential involvement of cognitive control regions between the CLP and DLP groups during linguistic switching vs. nonswitching at 450 to 515 ms poststimulus presentation. Moreover, there was a difference between CLP and DLP groups from 40 to 150 ms in the nonlinguistic task. Our electrophysiological results confirm a stronger involvement of language control and domain-general cognitive control regions in CLP bilinguals.

A Data-Based Approach for Selecting Pre- and Intra-Operative Language Mapping Tasks

Background: Pre- and intra-operative language mapping in neurosurgery patients frequently involves an object naming task. The choice of the optimal object naming paradigm remains challenging due to lack of normative data and standardization in mapping practices. The aim of this study was to identify object naming paradigms that robustly and consistently activate classical language regions and could therefore be used to improve the sensitivity of language mapping in brain tumor and epilepsy patients.Methods: Functional magnetic resonance imaging (fMRI) data from two independent groups of healthy controls (total = 79) were used to generate threshold-weighted voxel-based consistency maps. This novel approach allowed us to compare inter-subject consistency of activation for naming single objects in the visual and auditory modality and naming two objects in a phrase or a sentence.Results: We found that the consistency of activation in language regions was greater for naming two objects per picture than one object per picture, even when controlling for the number of names produced in 5 s.Conclusion: More consistent activation in language areas for naming two objects compared to one object suggests that two-object naming tasks may be more suitable for delimiting language eloquent regions with pre- and intra-operative language testing. More broadly, we propose that the functional specificity of brain mapping paradigms for a whole range of different linguistic and non-linguistic functions could be enhanced by referring to databased models of inter-subject consistency and variability in typical and atypical brain responses.

Computer Adaptive Testing for the Assessment of Anomia Severity

Anomia assessment is a fundamental component of clinical practice and research inquiries involving individuals with aphasia, and confrontation naming tasks are among the most commonly used tools for quantifying anomia severity. While currently available confrontation naming tests possess many ideal properties, they are ultimately limited by the overarching psychometric framework they were developed within. Here, we discuss the challenges inherent to confrontation naming tests and present a modern alternative to test development called item response theory (IRT). Key concepts of IRT approaches are reviewed in relation to their relevance to aphasiology, highlighting the ability of IRT to create flexible and efficient tests that yield precise measurements of anomia severity. Empirical evidence from our research group on the application of IRT methods to a commonly used confrontation naming test is discussed, along with future avenues for test development.

Identification of Word Retrieval Difficulties in the Normally Aging Population

Purpose This study examined variations in performance on different verbal tasks completed by typically aging, non-neurologically impaired adults who self-identified as either having or not having word retrieval difficulties that frequently affected their lifestyle. Method Fifty-seven adults aged 54–71 years, who were recruited based on case history responses that indicated the presence or absence of word retrieval difficulties, completed two standardized, norm-referenced language tests, two naming tasks, and three verbal fluency measures. Results Although scores on standardized language tests fell within normal limits for all of the participants, significant differences between those with and those without self-reported word retrieval difficulties were found on the Expressive Vocabulary Test–Second Edition as well as on tasks of naming members of categories and producing procedural narratives. A significantly greater percentage of disfluencies in procedural narratives were found in the group that reported word retrieval difficulties. This fluency indicator was the only factor that was predictive of word retrieval difficulties. Conclusions Many studies have examined the differences in word retrieval in older versus younger populations or in persons with aphasia versus persons without aphasia, but they have not offered definitive pictures of the differences between those with and those without word retrieval difficulties in the normally aging population who have otherwise normal language. This study identified three tasks that appear to be sensitive to the word-finding difficulties experienced by some adults.

Naming-related spectral responses predict neuropsychological outcome after epilepsy surgery

SUMMARYThis prospective study determined the utility of intracranially-recorded spectral responses during naming tasks in predicting neuropsychological performance following epilepsy surgery. We recruited 65 patients with drug-resistant focal epilepsy who underwent preoperative neuropsychological assessment and intracranial EEG (iEEG) recording. The Clinical Evaluation of Language Fundamentals (CELF) evaluated the baseline and postoperative language function. During extraoperative iEEG recording, we assigned patients to undergo auditory and picture naming tasks. Time-frequency analysis determined the spatiotemporal characteristics of naming-related amplitude modulations, including high gamma augmentation (HGA) at 70-110 Hz. We surgically removed the presumed epileptogenic zone based on the extent of iEEG and MRI abnormalities while maximally preserving the eloquent areas defined by electrical stimulation mapping (ESM). The multivariate regression model incorporating auditory naming-related HGA predicted the postoperative changes in Core Language Score (CLS) on CELF with r2 of 0.37 (p = 0.015) and in Expressive Language Index (ELI) with r2 of 0.32 (p = 0.047). Independently of the effects of epilepsy and neuroimaging profiles, higher HGA at the resected language-dominant hemispheric area predicted a more severe postoperative decline in CLS (p = 0.004) and ELI (p = 0.012). Conversely, the model incorporating picture naming-related HGA predicted the change in Receptive Language Index (RLI) with r2 of 0.50 (p < 0.001). Higher HGA independently predicted a more severe postoperative decline in RLI (p = 0.03). Ancillary regression analysis indicated that naming-related low gamma augmentation as well as alpha/beta attenuation likewise independently predicted a more severe CLS decline. The machine learning-based prediction model, referred to as the boosted tree ensemble model, suggested that naming-related HGA, among all spectral responses utilized as predictors, most strongly contributed to the improved prediction of patients showing a >5-point CLS decline (reflecting the lower 25 percentile among patients). We generated the model-based atlas visualizing sites, which, if resected, would lead to such a CLS decline. The auditory naming-based model predicted patients who developed the CLS decline with an accuracy of 0.80. The model indicated that virtual resection of an ESM-defined language site would have increased the relative risk of the CLS decline by 5.28 (95%CI: 3.47 to 8.02). Especially, that of an ESM-defined receptive language site would have maximized it to 15.90 (95%CI: 9.59-26.33). In summary, naming-related spectral responses predict objectively-measured neuropsychological outcome after epilepsy surgery. We have provided our prediction model as an open-source material, which will indicate the postoperative language function of future patients and facilitate external validation at tertiary epilepsy centers.

Cumulative semantic cost without successful naming

Accessing semantic information has negative consequences for successive recovering attempts of similar information. For instance, in the course of picture-naming tasks, the time required to name an object is determined by the total number of items from the same category that have already been named; naming latencies increase proportionally to the total number of semantically related words named previously. This phenomenon is called cumulative semantic cost (or interference). Two picture-naming experiments with children (4–11 years old, 229 participants) investigate whether having successfully named the previous within-category items is a necessary condition for the cumulative semantic cost to appear. We anticipated that younger children would have a larger rate of nonresponses compared with older children, reflecting the fact that younger children have not yet consolidated many lexical representations. Our results confirmed this prediction. Critically, we also observed that cumulative semantic cost was independent of having successfully retrieved previous within-category lexical items. Furthermore, picture trials for which the previous within-category item elicited a nonresponse showed the same amount of cost as those picture trials for which the previous within-category item elicited a correct naming event. Our findings indicate that it is the attempt to retrieve a lexical unit, and not the successful retrieval of a specific lexical unit, that causes semantic cost in picture naming. This cost can be explained by a mechanism of weakening the semantic-to-lexical mappings of semantic coordinate words. The findings are also discussed in the context of retrieval-induced forgetting effects in memory recall research.

Morpholexical Processes in Children with Autism Spectrum Disorder: Evidence from Artificial Word Learning

<b><i>Objectives:</i></b> This study aims to investigate the ability of high-functioning children with autism spectrum disorder and normal language (ALN) to learn artificial words, and to investigate their ability to use their knowledge of morphophonological patterns for this learning. <b><i>Methods:</i></b> Children with ALN and typically developing (TD) children, matched for cognitive and language measures, learned 8 artificial Hebrew words during two daily practice sessions by means of identification and naming tasks. Half the words were constructed from existing morphophonological patterns, and the other half were constructed from pseudo-morphophonological patterns. The two types of words allowed the investigation of the participants’ ability to use their knowledge of morphophonological patterns (morpholexical processes) for word learning. Both accuracy and speed were measured. <b><i>Results:</i></b> The ALN group improved incrementally at a rate (slope) similar to that of the TD group in identifying and naming the artificial words, in both accuracy and speed. However, the ALN group were slower than their TD peers in learning to identify the artificial words. Both groups demonstrated higher accuracy and faster speed in both tasks in learning the artificial words with existing morphophonological patterns than those with pseudo-patterns. However, this gap was smaller in the ALN group in the accuracy of naming and marginal in speed of identification. <b><i>Conclusions:</i></b> Children with ALN possess a lexical learning mechanism that is qualitatively not atypical but may be less efficient than that of their TD peers, including exploiting knowledge of morphophonological patterns – where such patterns exist – for word learning.

Errorless Learning Therapy in Semantic Variant of Primary Progressive Aphasia

Background: The semantic variant of primary progressive aphasia (svPPA) is characterized by a progressive loss of semantic knowledge impairing the ability to name and to recognize the meaning of words. Objective: We aimed to evaluate the immediate and short-term effect of errorless learning speech therapy on the naming and recognition of commonly used words in patients with svPPA. Methods: Eight participants diagnosed with svPPA received 16 sessions of intensive errorless learning speech therapy. Naming and word comprehension tasks were evaluated at baseline, immediately postintervention, and at follow-up after 1, 3, and 6 months. These evaluations were performed using two item sets (a trained list and an untrained list). Results: In the naming tasks, patients showed a significant improvement in trained items immediately after the intervention, but that improvement decayed progressively when therapy ended. No improvements were found either in trained comprehension or in untrained tasks. Conclusion: Errorless learning therapy could improve naming ability in patients with svPPA. This effect may be due to the relative preservation of episodic memory, but the benefit is not maintained over time, presumably because there is no consolidation.

Dynamics of Word Production in the Transition from Adolescence to Adulthood

Changes in word production occur across the lifespan. Previous studies have shown electrophysiological, temporal, and functional differences between children and adults accompanying behavioral changes in picture-naming tasks ( Laganaro, Tzieropoulos, Fraunfelder, & Zesiger, 2015 ). Thus, a shift toward adult-like processes in referential word production occurs somewhere between the ages of 13 and 20. Our aim was to investigate when and how children develop adult-like behavior and brain activation in word production. Toward this aim, performance and event-related potentials (ERP) in a referential word production task were recorded and compared for two groups of adolescents (aged 14 to 16 and 17 to 18), children (aged 10 to 13), and young adults (aged 20 to 30). Both groups of adolescents displayed adult-like production latencies, which were longer only for children, while accuracy was lower in the younger adolescents and in children, compared to adults. ERP waveform analysis and topographic pattern analysis revealed significant intergroup differences in key time-windows on stimulus-locked ERPs, both early (150–220 ms)—associated with pre-linguistic processes—and late (280–330 ms)—associated with lexical processes. The results indicate that brain activation underlying referential word production is completely adult-like in 17-year-old adolescents, whereas an intermediate pattern is still observed in adolescents aged 14 to 16 years old, although their production speed, but not their accuracy, is already adult-like.