Daniel Adrover-Roig

Construct validity of the Trail Making Test: Role of task-switching, working memory, inhibition/interference control, and visuomotor abilities

The aim of this study was to clarify which cognitive mechanisms underlie Trail Making Test (TMT) direct and derived scores. A comprehensive review of the literature on the topic was carried out to clarify which cognitive factors had been related to TMT performance. Following the review, we explored the relative contribution from working memory, inhibition/interference control, task-switching ability, and visuomotor speed to TMT performance. Forty-one healthy old subjects participated in the study and performed a battery of neuropsychological tests including the TMT, the Digit Symbol subtest [Wechsler Adult Intelligence Scale (Third Version) (WAIS-III)], a Finger Tapping Test, the Digits Forward and Backward subtests (WAIS-III), Stroop Test, and a task-switching paradigm inspired in the Wisconsin Card Sorting Test. Correlation and regression analyses were used in order to clarify the joint and unique contributions from different cognitive factors to the prediction of TMT scores. The results suggest that TMT-A requires mainly visuoperceptual abilities, TMT-B reflects primarily working memory and secondarily task-switching ability, while B-A minimizes visuoperceptual and working memory demands, providing a relatively pure indicator of executive control abilities.

Therapy-induced neuroplasticity in chronic aphasia

Research on the neural substrate of aphasia recovery has consistently increased since the advent of functional neuroimaging. The evidence from therapy-induced aphasia recovery studies shows that better recovery results from the reactivation of left hemisphere function; still, the specific left hemisphere key areas that sign successful outcome with a specific therapy approach remain to be identified. Nine participants suffering from aphasia received brief and intensive therapy with Semantic Feature Analysis (SFA). Behavioural and neuroimaging data during overt picture naming were obtained prior to and after therapy. This paper reports on a group of participants having benefited from SFA, and two distinct patterns of improvement. Correlational analysis showed that differences in outcome were not related to lesion size, but were negatively correlated with damage to Brocas area (BA45). Moreover, a group analysis showed that therapy-induced recovery following SFA was characterized by (a) a significant correlation between improvement and activation in the left precentral gyrus (BA4/6) before therapy, and (b) the recruitment of the left inferior parietal lobule, an area known for its role in semantic integration, following therapy with SFA. Individual fMRI analyses showed that although adaptive brain plasticity appeared to operate differently in each patient, best responders to SFA therapy recruited less areas after training compared to participants having shown less recovery who showed a larger number of activated areas sustaining recovery. The results of the present study suggest that a significant activation of BA4/6 could indicate the use of SFA to achieve successful outcome. Also our results suggest that greater SFA improvement in chronic aphasia is associated with recruitment of areas in the left hemisphere.

Brain activation and lexical learning: The impact of learning phase and word type

This study investigated the neural correlates of second-language lexical acquisition in terms of learning phase and word type. Ten French-speaking participants learned 80 Spanish words-40 cognates, 40 non-cognates-by means of a computer program. The learning process included the early learning phase, which comprised 5 days, and the consolidation phase, which lasted 2 weeks. After each phase, participants performed an overt naming task during an er-fMRI scan. Naming accuracy was better for cognates during the early learning phase only. However, cognates were named faster than non-cognates during both phases. The early learning phase was characterized by activations in the left iFG and Brocas area, which were associated with effortful lexical retrieval and phonological processing, respectively. Further, the activation in the left ACC and DLPFC suggested that monitoring may be involved during the early phases of lexical learning. During the consolidation phase, the activation in the left premotor cortex, the right supramarginal gyrus and the cerebellum indicated that articulatory planning may contribute to the consolidation of second-language phonetic representations. No dissociation between word type and learning phase could be supported. However, a Fisher r-to-z test showed that successful cognate retrieval was associated with activations in Brocas area, which could reflect the adaptation of known L1 phonological sequences. Moreover, successful retrieval of non-cognates was associated with activity in the anterior-medial left fusiform and right posterior cingulate cortices, suggesting that their successful retrieval may rely upon the access to semantic and lexical information, and even on the greater likelihood of errors.

Interference Control In Elderly Bilinguals: Appearances Can Be Misleading

Bilingualism has been associated with successful aging. In particular, research on the cognitive advantages of bilingualism suggests that it can enhance control over interference and help delay the onset of dementia signs. However, the evidence on the so-called cognitive advantage is not unanimous; furthermore, little is known about the neural basis of this supposed cognitive advantage in bilingual as opposed to monolingual elderly populations. In this study, elderly bilingual and monolingual participants performed a visuospatial interference control task during functional magnetic resonance imaging (fMRI) scanning. Response times and accuracy rates were calculated for congruent and incongruent conditions of the Simon task, and the neurofunctional correlates of performance on the Simon task were examined. The results showed equivalent performance on the Simon task across groups but different underlying neural substrates in the two groups. With incongruent trials, monolinguals activated the right middle frontal gyrus, whereas bilinguals relied upon the left inferior parietal lobule. These results show that elderly bilinguals and monolinguals have equivalent interference control abilities, but relay on different neural substrates. Thus, while monolinguals show a classical PASA (posterior–anterior shift in aging) effect, recruiting frontal areas, bilinguals activate visuospatial processing alone and thus do not show this posterior–anterior shift. Moreover, a modulation of frontal activity with task-dynamic control of interference, observed in the elderly bilingual group alone, suggests that elderly bilinguals deal with interference control without recruiting a circuit that is particularly vulnerable to aging.

Impaired L1 and executive control after left basal ganglia damage in a bilingual Basque-Spanish person with aphasia

Bilinguals must focus their attention to control competing languages. In bilingual aphasia, damage to the fronto-subcortical loop may lead to pathological language switching and mixing and the attrition of the more automatic language (usually L1). We present the case of JZ, a bilingual Basque–Spanish 53-year-old man who, after haematoma in the left basal ganglia, presented with executive deficits and aphasia, characterised by more impaired language processing in Basque, his L1. Assessment with the Bilingual Aphasia Test revealed impaired spontaneous and automatic speech production and speech rate in L1, as well as impaired L2-to-L1 sentence translation. Later observation led to the assessment of verbal and non-verbal executive control, which allowed JZs impaired performance on language tasks to be related to executive dysfunction. In line with previous research, we report the significant attrition of L1 following damage to the left basal ganglia, reported for the first time in a Basque–Spanish bilingual. Implications for models of declarative and procedural memory are discussed.

Early preschool processing abilities predict subsequent reading outcomes in bilingual Spanish-Catalan children with Specific Language Impairment (SLI).

UNLABELLED Children with Specific Language Impairment (SLI) have severe language difficulties without showing hearing impairments, cognitive deficits, neurological damage or socio-emotional deprivation. However, previous studies have shown that children with SLI show some cognitive and literacy problems. Our study analyses the relationship between preschool cognitive and linguistic abilities and the later development of reading abilities in Spanish-Catalan bilingual children with SLI. The sample consisted of 17 bilingual Spanish-Catalan children with SLI and 17 age-matched controls. We tested eight distinct processes related to phonological, attention, and language processing at the age of 6 years and reading at 8 years of age. Results show that bilingual Spanish-Catalan children with SLI show significantly lower scores, as compared to typically developing peers, in phonological awareness, phonological memory, and rapid automatized naming (RAN), together with a lower outcome in tasks measuring sentence repetition and verbal fluency. Regarding attentional processes, bilingual Spanish-Catalan children with SLI obtained lower scores in auditory attention, but not in visual attention. At the age of 8 years Spanish-Catalan children with SLI had lower scores than their age-matched controls in total reading score, letter identification (decoding), and in semantic task (comprehension). Regression analyses identified both phonological awareness and verbal fluency at the age of 6 years to be the best predictors of subsequent reading performance at the age of 8 years. Our data suggest that language acquisition problems and difficulties in reading acquisition in bilingual children with SLI might be related to the close interdependence between a limitation in cognitive processing and a deficit at the linguistic level. LEARNING OUTCOMES After reading this article, readers will be able to: identify their understanding of the relation between language difficulties and reading outcomes; explain how processing abilities influence reading performance in bilingual Spanish-Catalan children with SLI; and recognize the relation between language and reading via a developmental model in which the phonological system is considered central for the development of decoding abilities and comprehension.

Is bilingualism losing its advantage? A bibliometric approach

This study uses several bibliometric indices to explore the temporal course of publication trends regarding the bilingual advantage in executive control over a ten-year window. These indices include the number of published papers, numbers of citations, and the journal impact factor. According to the information available in their abstracts, studies were classified into one of four categories: supporting, ambiguous towards, not mentioning, or challenging the bilingual advantage. Results show that the number of papers challenging the bilingual advantage increased notably in 2014 and 2015. Both the average impact factor and the accumulated citations as of June 2016 were equivalent between categories. However, of the studies published in 2014, those that challenge the bilingual advantage accumulated more citations in June 2016 than those supporting it. Our findings offer evidence-based bibliometric information about the current state of the literature and suggest a change in publication trends regarding the literature on the bilingual advantage.

Interference control at the response level: Functional networks reveal higher efficiency in the bilingual brain

Abstract The bilingual advantage in interference control tasks has been studied with the Simon task, among others. The mixed evidence from the existing studies has led to contradictions in the literature regarding the bilingual advantage. Moreover, fMRI evidence on the neural basis of interference control mechanisms with the Simon task is limited. Previous work by our team showed that equivalent performance on the Simon task was associated with different activation maps in elderly bilinguals and monolinguals. This study aims to provide a more in-depth perspective on the neural bases of performance on the Simon task in elderly bilinguals and monolinguals, by adopting a network perspective for the functional connectivity analysis. A node-by-node analysis led to the identification of the specific topology that characterized the bilingual and monolingual functional networks and the degree of connectivity between each node across groups. Results showed greater connectivity in bilinguals in the inferior temporal sulcus, which plays a role in visuospatial processing. On the other hand, in monolinguals, brain areas involved in visual, motor, executive functions and interference control were more connected to resolve the same task. In other words, in comparison to the monolingual brain, the bilingual brain resolves visuospatial interference economically, by allocating fewer and more clustered regions. These results demonstrate a larger global efficiency in task performance in bilinguals as compared to monolinguals. Also, the provided evidence filters out the task-specific so-called bilingual advantage discussed in the literature and posits that bilinguals are strategically more efficient in a given performance than monolinguals, thus enhancing our understanding of successful aging.

Longitudinal trajectories of the representation and access to phonological information in bilingual children with specific language impairment

Purpose: Language development in children with Specific Language Impairment (SLI) is still poorly understood, especially if children with SLI are bilingual. This study describes the longitudinal trajectory of several linguistic abilities in bilingual children with SLI relative to bilingual control children matched by their age and socioeconomic status. Method: A set of measures of non-word repetition, sentence repetition, phonological awareness, rapid automatic naming and verbal fluency were collected at three time points, from 6–12 years of age using a prospective longitudinal design. Result: Results revealed that, at all ages, children with SLI obtained lower values in measures of sentence repetition, non-word repetition, phonological fluency and phonological awareness (without visual cues) when compared to typically-developing children. Other measures, such as rapid automatic naming, improved over time, given that differences at 6 years of age did not persist at further moments of testing. Other linguistic measures, such as phonological awareness (with visual cues) and semantic fluency were equivalent between both groups across time. Conclusion: Children with SLI manifest persistent difficulties in tasks involved in manipulating segments of words and in maintaining verbal units active in phonological working memory, while other abilities, such as the access to underlying phonological representations are unaffected.

Language Development in Bilingual Spanish-Catalan Children with and Without Specific Language Impairment: A Longitudinal Perspective

The present chapter explores both the cognitive and linguistic development of bilingual children with and without Specific Language Impairment (SLI), and focuses on Spanish and Catalan languages. We first describe some similarities between Monolingual and Bilingual language acquisition and how Bilingual children reach most of the milestones at the same age as monolinguals, despite having less exposure to each language separately. We refer to different characteristics of simultaneous bilingual language acquisition and discuss some variables that influence this process, such as the linguistic and non-linguistic characteristics that influence bilingual language acquisition and proficiency. One such variable is the status of each language in the social context. We highlight the advantages and disadvantages of being bilingual when compared with monolinguals in cognitive tasks related to information access and storage in long-term memory. We present several studies describing the development of monolingual children with SLI to establish a basis for comparing bilingual children with SLI. We mention some studies which have explored cognitive abilities in bilingual children with SLI; some studies finding compensating abilities and some others finding a “bilingual disadvantage”. We show several studies with different outcomes depending on the type of bilingualism, such as the differences between sequential bilinguals as compared to simultaneous bilingual children. Finally, we present a series of studies that have investigated phonological, morphosyntactic, lexical-semantic and pragmatic characteristics of bilingual Spanish-Catalan development in children with and without SLI. Executive functions related to both cognitive and language processing in bilingual Spanish-Catalan acquisition are also shown. The chapter ends with some research which have analyzed reading abilities and social interaction in this population.