Verbal fluency over time as a measure of automatic and controlled processing in children with ADHD

Symptoms of ADHD and Autism Spectrum Disorder Interactively Predict Children's Verbal Fluency

OBJECTIVE

Verbal fluency, the capacity to generate words from a designated category, predicts myriad cognitive and life outcomes. The study investigated verbal fluency in children with ADHD, autism spectrum disorder (ASD), and comorbid ADHD and ASD, to understand how ADHD- and ASD-related symptoms individually and jointly predict verbal fluency, and the underlying linguistic and cognitive substrates.

METHOD

Thirty-three school-aged children with ADHD, 27 with ASD, 25 with comorbid ADHD and ASD, and 39 with typical development, were assessed for ADHD and ASD symptoms and completed a semantic verbal fluency task.

RESULTS

Findings indicated that ADHD and ASD symptoms, especially ADHD hyperactivity-impulsivity symptoms and language-related ASD symptoms, interactively predicted verbal fluency across diagnostic groups.

CONCLUSION

The study implicated the potential cognitive and linguistic mechanisms underlying verbal fluency differences in ADHD and/or ASD, and clinical practices on enhancing verbal fluency in these clinical groups.

Norms, convergent validity, test-retest reliability, and practice effects for verbal fluency overall performance, clustering, and switching in Spanish-speaking children

OBJECTIVE

We conducted two empirical studies (in a cross-sectional and a longitudinal design) with the aim at establishing normative data (including norms for strategy use [i.e., clustering and switching strategies] and performance over time), and examining the convergent validity, the test-retest reliability (3-4 wks interval) and the changes in performance with practice (1 year interval) of the different verbal fluency (VF) quantitative and qualitative scores in Spanish-speaking children and adolescents.

METHOD

In S1 (n = 620 6- to 15-year-old Spanish-speaking children and adolescents), MANCOVA and Pearson's correlations were employed. In S2 (n = 148 6- to 12-year-old Spanish-speaking children), intraclass correlation coefficient (ICC), paired t-tests, and Confirmatory Factor Analysis (CFA) were used.

RESULTS

S1 results showed an age effect on all VF measures (quantitative and qualitative). The number of switches/clusters was more related to total word productivity and to executive functions (EF) than the mean cluster size. In S2, a significant increase in phonological VF performance was observed on number of switches and word productivity scores from baseline (Time 1) to repeat testing at Time 2. Practice effects were observed at Time 3 on all measures except for semantic and phonological mean cluster size. Test-retest reliability coefficients at Time 2 for number of clusters and switches, but not for mean cluster size, fell in the moderate range, ranging from ICCs .61 to ICCs .81. Test-retest reliability coefficients for total word productivity were higher (ICCs above .80) and stronger when testing as a unity with CFA methods (ϕ=.94, p < .001).

CONCLUSIONS

These data may be relevant for informing the neuropsychological assessment of spontaneous cognitive flexibility in children with typical development (TD) and those with developmental or acquired disorders.

A Systematic Review of Normative Data for Verbal Fluency Test in Different Languages

Verbal fluency tests are easy and quick to use in neuropsychological assessments, so they have been counted among the most classical tools in this context. To date, several normative data for verbal fluency tests have been provided in different languages and countries. A systematic review was carried out with studies that provide normative data for verbal fluency tests. Studies were collected from Scopus, PubMed and Web of Science. 183 studies were retrieved from the database search, of which 73 finally met the inclusion criteria. An analysis of the risk of bias regarding samples selection/characterization and procedure/results reports is conducted for each article. Finally, a full description of the normative data characteristics, considering country and language, verbal fluency task characteristics (type of task) and sample characteristics (number of subjects, gender, age, education) is included. The current systematic review provides an overview and analysis of internationally published normative data that might help clinicians in their search for valid and useful norms on verbal fluency tasks, as well as updated information about qualitative aspects of the different options currently available.

Transcranial Direct-Current Stimulation Improves Verbal Fluency in Children with Attention Deficit Hyperactivity Disorder (ADHD)

Individuals with attention deficit hyperactivity disorder (ADHD) struggle with impaired verbal fluency as an executive function. The left and right dorsolateral prefrontal cortex (dlPFC) and the right inferior frontal gurus (IFG), which show reduced functionality in individuals with ADHD, are involved in verbal fluency. In this study, a total of thirty-seven children with ADHD participated in two separate experiments. Each experiment included three different stimulation conditions: anodal left dlPFC/cathodal right vmPFC stimulation, the reversed montage, and a sham stimulation in Experiment 1, and anodal right dlPFC, anodal right IFG with extracranial return electrode, and a sham stimulation in Experiment 2. During each session, participants performed semantic and phonemic verbal fluency tasks while receiving tDCS. The results revealed a significant main effect of stimulation condition on phonemic verbal fluency during anodal left dlPFC stimulation in Experiment 1, and on semantic verbal fluency during both real stimulation conditions in Experiment 2. In conclusion, this study suggests that anodal left dlPFC stimulation improves phonemic verbal fluency, while anodal right dlPFC and right IFG stimulation enhance semantic verbal fluency. This domain-specific improvement can be attributed to the distinct cognitive demands of phonemic and semantic verbal fluency tasks. Phonemic verbal fluency heavily relies on working memory processes, whereas semantic verbal fluency requires effective inhibitory control and cognitive flexibility.

Current Understanding of Verbal Fluency in Alzheimer's Disease: Evidence to Date

Since their development, verbal fluency tests (VFTs) have been used extensively throughout research and in clinical settings to assess a variety of cognitive functions in diverse populations. In Alzheimer's disease (AD), these tasks have proven particularly valuable in identifying the earliest forms of cognitive decline in semantic processing and have been shown to relate specifically to brain regions associated with the initial stages of pathological change. In recent years, researchers have developed more nuanced techniques to evaluate verbal fluency performance, extracting a wide range of cognitive metrics from these simple neuropsychological tests. Such novel techniques allow for a more detailed exploration of the cognitive processes underlying successful task performance beyond the raw test score. The versatility of VFTs and the richness of data they may provide, in light of their low cost and speed of administration, therefore, highlight their potential value both in future research as outcome measures for clinical trials and in a clinical setting as a screening measure for early detection of neurodegenerative diseases.

Verbal Fluency in Prelingually Deaf, Early Implanted Children and Adolescents With Cochlear Implants

PURPOSE

Verbal fluency tasks assess the ability to quickly and efficiently retrieve words from the mental lexicon by requiring subjects to rapidly generate words within a phonological or semantic category. This study investigated differences between cochlear implant users and normal-hearing peers in the clustering and time course of word retrieval during phonological and semantic verbal fluency tasks.

METHOD

Twenty-eight children and adolescents (aged 9-17 years) with cochlear implants and 33 normal-hearing peers completed measures of verbal fluency, nonverbal intelligence, speech perception, and verbal short-term/working memory. Phonological and semantic verbal fluency tests were scored for total words generated, words generated in each 10-s interval of the 1-min task, latency to first word generated, number of word clusters, average cluster size, and number of word/cluster switches.

RESULTS

Children and adolescents with cochlear implants generated fewer words than normal-hearing peers throughout the entire 60-s time interval of the phonological and semantic fluency tasks. Cochlear implant users also had slower start latency times and produced fewer clusters and switches than normal-hearing peers during the phonological fluency task. Speech perception and verbal working memory scores were more strongly associated with verbal fluency scores in children and adolescents with cochlear implants than in normal-hearing peers.

CONCLUSIONS

Cochlear implant users show poorer phonological and semantic verbal fluency than normal-hearing peers, and their verbal fluency is significantly associated with speech perception and verbal working memory. These findings suggest deficits in fluent retrieval of phonological and semantic information from long-term lexical memory in cochlear implant users.

Executive functioning and verbal fluency performance in youth with Down syndrome

BACKGROUND

Executive functioning (EF) is an area of challenge for individuals with Down syndrome (DS) associated with a variety of downstream difficulties. Verbal fluency performance is one potential downstream effect that is commonly assessed in individuals with DS due to the measure's utility as a predictor of dementia. Verbal fluency requires individuals to inhibit irrelevant responses, shift between groupings of related words, and monitor to prevent repetition, all skills related to EF.

AIMS

This study aimed to determine the association between semantic verbal fluency performance and three EF subdomains (inhibition, shifting, and working memory) in youth with DS after taking into account vocabulary and cognitive ability.

METHODS AND PROCEDURES

Neuropsychological assessments (verbal and visuospatial), and parent reports of EF, were completed at one time point by 69 youth with DS 6-17 years old and their caregivers. Expressive and receptive vocabulary skills and cognitive ability were also assessed.

OUTCOMES AND RESULTS

The results revealed that verbal fluency performance was significantly associated with neuropsychological assessments of EF and parent report of inhibition even after controlling for the effects of vocabulary and cognitive ability.

CONCLUSIONS AND IMPLICATIONS

The findings highlight the underlying importance of EF in verbal fluency tasks in youth with DS.

Visual-motor attention in children with ADHD: The role of automatic and controlled processes

BACKGROUND

there are evidence that children with ADHD exhibit a deficit both in automatic and controlled processes.

AIMS

the present study aimed to examine the visual-motor attention and the influence of cognitive load through a dual task paradigm in children with ADHD compared with typical developing children (TD).

METHODS AND PROCEDURES

113 children with ADHD: 40 with subtype inattentive (ADHD- I group), 16 with subtype hyperactive (ADHD-H group), 57 with subtype combined (ADHD-C group), and 113 TD children (TD group) were recruited. We used a dual-task paradigm in which the primary task was a figure-tracing test whereas the second task was a digit span test. A figure-tracing test was used to evaluate visual motor attention. Based on the length and intersection of the lines, the figures of the primary task were categorized into simple and complex.

OUTCOMES AND RESULTS

the ADHD groups compared to the TD group showed a worse accuracy of performance in both condition with and without cognitive load.

CONCLUSIONS AND IMPLICATIONS

The findings were discussed in light of the relationship between automatic and controlled processes involved in the visual-motor attention.

Serial Recall Order of Category Fluency Words: Exploring Its Neural Underpinnings

Background: Although performance on the category fluency test (CFT) is influenced by many cognitive functions (i.e., including language, executive functioning and speed of processing), item-level scoring methods of CFT performance might be a promising way to capture aspects of semantic memory that are less influenced by intervenient abilities. One such approach is based on the calculation of correlation coefficients that quantify the association between item-level features and the serial order with which words are recalled (SRO).

Methods: We explored the neural underpinnings of 10 of these correlational indices in a sample of 40 healthy adults who completed a classic 1-min CFT and an MRI protocol inclusive of T1-weighted (analysed with voxel-based morphometry) and resting-state fMRI sequences for the evaluation of the default-mode network (DMN). Two sets of linear models were defined to test the association between neural maps and each correlational index: a first set in which major demographic and clinical descriptors were controlled for and a second set in which, additionally, all other 9 correlational indices were regressed out.

Results: In the analysis of the DMN, ‘SRO-frequency’, ‘SRO-dominance’ and ‘SRO-body-object interaction’ correlational indices were all negatively associated with the anterior portion of the right temporoparietal junction. The ‘SRO-frequency’ correlational index was also negatively associated with the right dorsal anterior cingulate and the ‘SRO-dominance’ correlational index with the right lateral prefrontal cortex. From the second set of models, the ‘SRO-typicality’ correlational index was positively associated with the left entorhinal cortex. No association was found in relation to grey matter maps.

Conclusion: The ability to retrieve more difficult words during CFT performance as measured by the correlational indices between SRO and item-level descriptors is associated with DMN expression in regions deputed to attentional reorienting and processing of salience of infrequent stimuli and dominance status. Of all item-level features, typicality appears to be that most closely linked with entorhinal functioning and may thus play a relevant role in assessing its value in testing procedures for early detection of subtle cognitive difficulties in people with suspected Alzheimer’s degeneration. Although exploratory, these findings warrant further investigations in larger cohorts.

Serial Recall Order and Semantic Features of Category Fluency Words to Study Semantic Memory in Normal Ageing

Background: Category Fluency Test (CFT) is a common measure of semantic memory (SM). Test performance, however, is also influenced by other cognitive functions. We here propose a scoring procedure that quantifies the correlation between the serial recall order (SRO) of words retrieved during the CFT and a number of linguistic features, to obtain purer SM measures. To put this methodology to the test, we addressed a proof-of-concept hypothesis whereby, in alignment with the literature, older adults would show better SM. Methods: Ninety participants (45 aged 18-21 years; 45 aged 70-81 years) with normal neurological and cognitive functioning completed a 1-min CFT. SRO was scored as an ordinal variable incrementing by one unit for each valid entry. Each word was also scored for 16 additional linguistic features. Participant-specific normalised correlation coefficients were calculated between SRO and each feature and were analysed with group comparisons and graph theory. Results: Younger adults showed more negative correlations between SRO and "valence" (a feature of words pleasantness). This was driven by the first five words generated. When analysed with graph theory, SRO had significantly higher degree and lower betweenness centrality among older adults. Conclusion: In older adults, SM relies significantly less on pleasantness of entries typically retrieved without semantic control. Moreover, graph-theory metrics indicated better optimised links between SRO and linguistic features in this group. These findings are aligned with the principle whereby SM processes tend to solidify with ageing. Although additional work is needed in support of an SRO-based item-level scoring procedure of CFT performance, these initial findings suggest that this methodology could be of help in characterising SM in a purer form.

ADHD Symptomatology, Executive Function and Cognitive Performance Differences between Family Foster Care and Control Group in ADHD-Diagnosed Children

Children in foster care have a high prevalence of attention deficit and hyperactivity disorder (ADHD) diagnosis, together with other difficulties in inattentive/hyperactive behaviors, executive and cognitive processes. Early exposure to adversity is a risk factor for developing ADHD via neurodevelopmental pathways. The goal of this research is (a) to study the cognitive and executive performance and inattentive/hyperactive behavior of ADHD-diagnosed children living in foster families in Spain, and (b) to analyze the role of placement variables in their performance. The sample was composed of 102 ADHD-diagnosed children aged 6- to 12-years-old, divided into two groups: 59 children living with non-relative foster families and 43 children not involved with protection services. Children’s executive function–inhibition, working memory, flexibility, attention, intellectual capacity, verbal comprehension, perceptive reasoning, working memory and processing speed were assessed using objective testing measures. At the same time, parents and teachers reported on children’s inattentive, hyperactive and impulsive behaviors. Children in foster care obtained lower scores in the general ability index than the control group after controlling the age at assessment. However, no differences were found in executive processes. Regarding placement factors, children with shorter exposure to adversities in their birth families and more time in foster care showed better executive performance. Professionals should consider the placement history of children in foster care and its influence on their symptomatology and cognitive capacities.

The Influence of Antisocial Behavior and Callous-Unemotional Traits on Trajectories of School Engagement and Achievement in South-Korean Children

Poor educational outcomes are common among children with antisocial behavior problems, including among a subgroup of antisocial children with callous-unemotional traits, who show deficits in empathy, guilt, and prosociality. However, few studies have explored the unique contributions of antisocial behavior and callous-unemotional traits to school outcomes and most prior studies have been conducted in Western countries. The current study thus tested associations between callous-unemotional traits, antisocial behavior, and trajectories of school outcomes among South Korean children. Participants aged 10-12 years (N = 218; 52% boys) completed questionnaires assessing antisocial behavior, callous-unemotional traits, verbal ability, and school engagement, and teachers provided children's Math and Korean grades at three time points during a single academic year. Prospective associations were explored in conditional latent growth curve models. Both antisocial behavior and callous-unemotional traits were related to lower school engagement at the start of the academic year, but the magnitude of the associations was greater for callous-unemotional traits, suggesting a greater adverse effect of callous-unemotional traits on engagement than antisocial behavior. Moreover, children with high levels of callous-unemotional traits showed stable and low levels of school engagement. There were no significant predictive associations between antisocial behavior or callous-unemotional traits and trajectories of academic grades. The findings suggest that interventions aimed at improving educational outcomes among antisocial children should be tailored according to the presence of callous-unemotional traits to target the specific needs of individual students, particularly at the start of the school year.

Verbal Fluency Development Across Childhood: Normative Data from Brazilian-Portuguese Speakers and Underlying Cognitive Processes

OBJECTIVE

Verbal fluency (VF) tasks are widely used to investigate children's lexical knowledge and executive functions skills. Consistency of measurement of the strategic retrieval components is still an issue and performance of Brazilian-Portuguese speaking children are currently not available. A cross-sectional study investigated the effects of age, school type (public × private) and the influence of language, memory and inhibitory control on VF.

METHOD

We assessed 414 Brazilian children, aged 6-12, in the number of words produced and both clustering and switching components, with two measures of VF: letter (LVF) and semantic (SVF).

RESULTS

Analysis of the number of words produced showed a significant increase between 6-8-year-olds, 9-10-year-olds and 11-12-year-olds in SVF, while in LVF, the differences were significant only in the later age group. In SVF, the numbers of clusters and switches increased with age, whereas in LVF, the number of switches increased in all age groups, but clusters increased only in the older group. Structural equation model analyses showed that oral and written language, verbal memory and inhibitory control are associated with VF performance and IQ, while age mediated VF performance.

CONCLUSIONS

The results indicate a different development pattern between LVF and SVF in the number of words produced and in clustering and switching, with the latter predicting VF performance in words produced. VF development is shown to depend on language, memory and inhibitory control. Our results have important implications to clinical neuropsychology.

Multi-Source Interference Task paradigm to enhance automatic and controlled processes in ADHD

BACKGROUND

The role of automatic and controlled processes in children with Attention deficit hyperactivity disorder (ADHD) has recently been debated. Most theories on ADHD assume that core deficits are related to controlled processes and executive function.

AIMS

The main aim of the present study is to examine automatic and controlled attention in children with ADHD, compared to TD subjects.

METHODS AND PROCEDURES

Twenty ADHD-I children, 20 with ADHD-C and 20 typical developing children performed the Block-Formed Multi-Source Interference Task (MSIT) both in incongruent and congruent conditions.

OUTCOME AND RESULTS

Results show that clinical groups had a poorer performance than the TD group in both conditions.

CONCLUSIONS AND IMPLICATIONS

This study demonstrated that children with ADHD exhibit a deficit both in automatic and controlled processes.

Lower Attentional Skills predict increased exploratory foraging patterns

When engaged in a search task, one needs to arbitrate between exploring and exploiting the environment to optimize the outcome. Many intrinsic, task and environmental factors are known to influence the exploration/exploitation balance. Here, in a non clinical population, we show that the level of inattention (assessed as a trait) is one such factor: children with higher scores on an ADHD (Attention Deficit/Hyperactivity Disorder) questionnaire exhibited longer transitions between consecutively retrieved items, in both a visual and a semantic search task. These more frequent exploration behaviours were associated with differential performance patterns: children with higher levels of ADHD traits performed better in semantic search, while their performance was unaffected in visual search. Our results contribute to the growing literature suggesting that ADHD should not be simply conceived as a pure deficit of attention, but also as a specific cognitive strategy that may prove beneficial in some contexts.

Influence of age and education on the processing of clustering and switching in verbal fluency tasks

Verbal fluency (VF) is a widely used tool in neuropsychological assessment.

Quantitative and qualitative analysis of semantic verbal fluency in patients with temporal lobe epilepsy

INTRODUCTION

Patients with temporal lobe epilepsy (TLE) perform poorly on semantic verbal fluency (SVF) tasks. Completing these tasks successfully involves multiple cognitive processes simultaneously. Therefore, quantitative analysis of SVF (number of correct words in one minute), conducted in most studies, has been found to be insufficient to identify cognitive dysfunction underlying SVF difficulties in TLE.

OBJECTIVES

To determine whether a sample of patients with TLE had SVF difficulties compared with a control group (CG), and to identify the cognitive components associated with SVF difficulties using quantitative and qualitative analysis.

METHODS

SVF was evaluated in 25 patients with TLE and 24 healthy controls; the semantic verbal fluency test included 5 semantic categories: animals, fruits, occupations, countries, and verbs. All 5 categories were analysed quantitatively (number of correct words per minute and interval of execution: 0-15, 16-30, 31-45, and 46-60seconds); the categories animals and fruits were also analysed qualitatively (clusters, cluster size, switches, perseverations, and intrusions).

RESULTS

Patients generated fewer words for all categories and intervals and fewer clusters and switches for animals and fruits than the CG (P<.01). Differences between groups were not significant in terms of cluster size and number of intrusions and perseverations (P>.05).

CONCLUSIONS

Our results suggest an association between SVF difficulties in TLE and difficulty activating semantic networks, impaired strategic search, and poor cognitive flexibility. Attention, inhibition, and working memory are preserved in these patients.

Ineffective initiation contributes to deficient verbal and non-verbal fluency in patients with schizophrenia

AIMS

Patients with schizophrenia (SCH) show impaired verbal and non-verbal fluency. However, these individuals' fluctuations in words or designs generation efficiency over time, a phenomenon that may significantly affect fluency, have never been studied. Thus, the aim of this research was to investigate if individuals with SCH may present with alternations in the dynamics of the information production and its control as well as to test if the potential abnormalities in this regard might affect these patients' overall performance on both verbal and non-verbal fluency tasks.

METHOD

Forty-four patients with SCH and 40 healthy controls (HC) completed both verbal (phonological, semantic) and non-verbal fluency tests. To analyse processing efficiency changes over time, the period in which subjects had to generate words or designs (60 s) has been divided into 15-s sections.

RESULTS

In comparison to HCs, individuals with SCH obtained significantly lower total scores for all fluency measures. Furthermore, group differences in the dynamics of the test performance also emerged, with SCH patients having a significantly worse production during the initial 15 s of each fluency task. Additionally, the initial production deficiency seen in patients with SCH has accounted for these individuals' total performance. Moreover, comparisons of errors distribution over time during the phonemic and figural fluency performance also revealed differences, suggesting there was a rapid depletion in maintaining of cognitive control in the SCH sample.

CONCLUSIONS

Inefficient fluency in SCH may arise from a more general initiation deficits that may partly account for these patients' cognitive problems.

Semantic fluency in aphasia: clustering and switching in the course of 1 minute

BACKGROUND

Verbal fluency tasks are included in a broad range of aphasia assessments. It is well documented that people with aphasia (PWA) produce fewer items in these tasks. Successful performance on verbal fluency relies on the integrity of both linguistic and executive control abilities. It remains unclear if limited output in aphasia is solely due to their lexical retrieval difficulties or has a basis in their executive control abilities. Analysis techniques, such as temporal characteristics of word retrieved, clustering and switching, are better positioned to inform the debate surrounding the lexical and/or executive control contribution for success in verbal fluency.

AIMS

To investigate the differences in quantitative (i.e., number of correct words) and qualitative (i.e., switching, clustering and word-retrieval times) performances on animal fluency task as a function of time between PWA and healthy control speakers (CS).

METHODS & PROCEDURES

Animal fluency data for 60 s were collected from 34 PWA and 34 CS, and responses were time stamped. The 60-s period was divided into four equal intervals of 15 s each (i.e., 15, 30, 45 and 60 s). The number of correct words, cluster size, number of switches, within-cluster pause and between-cluster pause were evaluated as a function of four 15-s time intervals between PWA and CS.

OUTCOMES & RESULTS

Compared with CS, PWA produced fewer words, had smaller cluster sizes and switched a fewer number of times. A decrease in the number of switches correlated with an increase in between-cluster pause durations. PWA showed longer within- and between-cluster pauses than CS. The two groups showed specific differences in the temporal pattern of the responses: as time evolved both PWA and CS showed decreased productivity for the number of correct words, but PWA reached the asymptote earlier in the time course than CS, neither group showed a change in cluster size, and the number of switches decreased as a function of time only for CS.

CONCLUSIONS & IMPLICATIONS

The findings suggest that for PWA the search and retrieval process is less productive and more effortful. This is indicated by smaller cluster size, fewer switches associated with increased between-cluster pause durations, as well as overall slowed retrieval times for the words. This shows that the difficulties with verbal fluency performance in aphasia have a strong basis in their lexical retrieval processes, as well as some difficulties in the executive component of the task.

Cognitive functioning in children with internalising, externalising and dysregulation problems: a population-based study

Psychiatric symptoms in childhood are closely related to neurocognitive deficits. However, it is unclear whether internalising and externalising symptoms are associated with general or distinct cognitive problems. We examined the relation between different types of psychiatric symptoms and neurocognitive functioning in a population-based sample of 1177 school-aged children. Internalising and externalising behaviour was studied both continuously and categorically. For continuous, variable-centred analyses, broadband scores of internalising and externalising symptoms were used. However, these measures are strongly correlated, which may prevent identification of distinct cognitive patterns. To distinguish groups of children with relatively homogeneous symptom patterns, a latent profile analysis of symptoms at age 6 yielded four exclusive groups of children: a class of children with predominantly internalising symptoms, a class with externalising symptoms, a class with co-occurring internalising and externalising symptoms, that resembles the CBCL dysregulation profile and a class with no problems. Five domains of neurocognitive ability were tested: attention/executive functioning, language, memory and learning, sensorimotor functioning, and visuospatial processing. Consistently, these two different modelling approaches demonstrated that children with internalising and externalising symptoms show distinct cognitive profiles. Children with more externalising symptoms performed lower in the attention/executive functioning domain, while children with more internalising symptoms showed impairment in verbal fluency and memory. In the most severely affected class of children with internalising and externalising symptoms, we found specific impairment in the sensorimotor domain. This study illustrates the specific interrelation of internalising and externalising symptoms and cognition in young children.

Mild Cognitive Impairments Moderate the Effect of Time on Verbal Fluency Performance

OBJECTIVES

Mild cognitive impairments (MCI) is a transitional state in aging associated with increased risk of incident dementia. The current study investigated whether MCI status moderated the effect of time on word generation during verbal fluency tasks. Specifically, the objective was to determine whether MCI status had differential effects on initial automatic or latter more effortful retrieval processes of fluency tasks.

METHODS

Participants were community residing older adults enrolled in a longitudinal cohort study. Of the 408 participants, 353 were normal (age=76.06±6.61; %female=57.8) and 55 were diagnosed with MCI (age=78.62±7.00; %female=52.7). Phonemic and category fluency were each administered for 60 s, but performance was recorded at three consecutive 20-s intervals (0-20 s [T1], 21-40 s [T2], 41-60 s [T3]. Separate linear mixed effects models for each fluency task were used to determine the effects of group, time, and their interaction on word generation.

RESULTS

In both fluency tasks, word generation declined as a function of time. Individuals with MCI generated fewer words compared to controls during the first 20 s of phonemic (beta=-1.56; p<.001; d=0.28) and category fluency (beta=-1.85; p<.001; d=0.37). Group by time interactions revealed that individuals with MCI demonstrated attenuated declines in word generation from the first to the second and third time intervals of both phonemic ([T1 vs. T2] beta=2.17, p=.001; d=0.41; [T1 vs. T3]beta=2.28, p=.001; d=0.45) and category ([T1 vs. T2] beta= 2.22, p=.002; d=0.50; [T1 vs. T3]beta=3.16, p<.001; d=0.71) fluency.

CONCLUSIONS

Early automatic retrieval processes in verbal fluency tasks are compromised in MCI. (JINS, 2017, 23, 44-55).

ADHD: Auditory and Visual Stimuli in Automatic and Controlled Processes

OBJECTIVE

Deficits in ADHD executive function (EF) task have been widely documented in a number of different studies. The aim of this work is to analyze the characteristics of auditory vigilance in ADHD and control subjects in two conditions: with and without interference.

METHOD

in the first study the Merrill's (1992) procedure on automaticity with the dual-task interference paradigm was used; in the second study the auditory test with automatic procedure was used.

RESULTS

The results of the study confirm that people with ADHD show deficits in auditory vigilance tests and become less careful when interference is introduced.

CONCLUSION

Results were discussed in terms of a deficit in automaticity process.

Semantic retrieval over time in the aging brain: Structural evidence of hippocampal contribution

This study investigates relationship between regional cerebral volumes and performances over time of a categorical fluency task, in a sample of older adults (n = 316). Using voxel-wise technique, the relationship between local grey matter volume and Isaacs Set Test (IST) scores at its early (first 15 sec) and late (last 15 sec) phase production was analyzed with a linear regression model adjusting for age, sex, educational level, ApoEɛ4 allele, handedness and Grey Matter atrophy. Lower early IST scores were associated with smaller volumes in bilateral inferior frontal gyri and in right thalamus, whereas lower late IST scores were associated to smaller left inferior parietal gyrus and left anterior hippocampus. An analysis based on automatic segmentation of hippocampus confirmed the latest relationship which cannot be attributed to the correlation of each variable with global cognitive impairment because it remained when MMSE was accounted for. We observed a switch from frontal to temporo-parietal regions as words retrieval become more difficult over time. Automatic speech production of the early phase of the category fluency task is dependent on executive networks integrity whereas controlled speech production of the late phase is dependent on memory networks integrity, including left hippocampus. These results are concordant with recent imaging studies expanding the implication of hippocampus to semantic memory performances and they underlie the need to consider verbal fluency task over time.

Analysis of young children's abilities to cluster and switch during a verbal fluency task

To investigate developmental changes that take place in verbal fluency (VF) performance during early childhood, a VF task was administered to 225 healthy, Dutch-speaking children aged between 4.14 and 6.89 years. Three categories of VF outcome measures were included: i.e., word productivity, mean cluster size, and number of switches. Age influenced performance on all VF outcome measures linearly; i.e., older children produced more words, made longer clusters, and switched more. Higher levels of intelligence were associated with increased VF word productivity, but not with measures of switching and clustering. When leaving intelligence out of these analyses, we additionally found an interaction between level of parental education (LPE) and sex on total word productivity, i.e., girls with parents who had lower LPE produced fewer words than the other children. Furthermore, a similar interaction of LPE and sex was found for the number of switches: i.e., girls who had parents with lower LPE made fewer switches than the other children. Findings suggest that even in 4 to 6-year-old children important changes take place over time in VF and in processes underlying successful performance. Attention should be paid to age-extrinsic factors, such as LPE and sex, since these have been found to influence VF performance in young children.

Developmental changes in frontal lobe function during a verbal fluency task: a multi-channel near-infrared spectroscopy study

OBJECTIVE

Near-infrared spectroscopy (NIRS) is commonly used to investigate continuous changes of brain activation and has excellent time resolution. Verbal fluency task (VFT) is widely used as a neuropsychological test of frontal lobe function. The aim of this study was to investigate normal developmental change in frontal lobe function during VFT performance using multi-channel NIRS, specifically focusing on oxygenation hemoglobin (oxyHb) changes.

METHODS

The subjects were 9 adults and 37 childrens who were all healthy right-handed volunteers. Children were divided into four age groups (group A, 6-8 years; group B, 9-11 years; group C, 12-14 years; group D, 15-18 years). The [oxyHb] changes were measured with 22 channels of NIRS during VFT. We defined the frontopolar region as the region of interest for analysis, and calculated the Z-score to compare the data between groups.

RESULTS

The task performance changed with age. There were significant differences between group A and other groups. The Z-score of [oxyHb] also significantly increased with age, when comparing adults to groups A and B. The task performances decreased with time in all groups. In contrast, [oxyHb] only continued to increase in the adult group.

CONCLUSION

The verbal retrieval functions begin to mature in early adolescence and continue to grow up to adulthood.

Executive functioning in children with developmental dyslexia

The term "executive function" has been used to describe several higher-order cognitive processes. This study examined the processing speed, shifting, planning, and verbal fluency of a sample of 50 Portuguese children with developmental dyslexia (DD) and 50 typically developing children (TDC; chronological-age-matched controls) between 8 and 12 years of age to evaluate the children's executive functioning. Compared to TDC, children with DD revealed significant processing speed, shifting, and verbal fluency deficits. After controlling for differences in the general intellectual ability, significant group differences remained for shifting, verbal fluency and marginally for processing speed. No significant differences in planning ability were observed between the groups. No significant interaction of group, gender, and age was found for any of the executive functions measures studied. Word productivity in both semantic and phonemic verbal fluency tasks decreased significantly over the 60 seconds for both groups. Shifting was the only significant predictor of DD in the binary logistic regression analysis and yielded the highest area under the curve value (receiver operating characteristics curve analysis). Therefore, although these findings highlight the presence of specific executive functions deficits in children with DD, they should not be interpreted as indicative of the presence or absence of this learning disorder.

Verbal fluency in right brain damage: dissociations among production criteria and duration

This study aimed to verify dissociations in the performance of verbal fluency tasks with different production criteria and duration following vascular right-hemisphere damage. We tested the hypothesis that longer fluency tasks would be more sensitive in identifying deficits in the sample. The relationship between verbal fluency performance and sustained attention was also investigated. Forty adults with vascular right-hemisphere damage were assessed using verbal fluency tasks with three different production criteria (unconstrained, phonemic, and semantic fluencies from the Montreal Communication Evaluation Battery). Performance deficits in 1-min and 2-min fluency tasks were calculated (Z score) and compared (chi-square). Results did not suggest a difference in sensitivity between the task lengths in detecting cognitive impairment. However, double dissociations were found, highlighting the contribution of extended verbal fluency tasks to neuropsychological assessment. Analyses also showed that participants exhibited greater levels of impairment in the semantic fluency task. No relationship was identified between performance in sustained attention tasks and verbal fluency tasks, regardless of the latter's duration. The combined use of longer and shorter fluency tasks in the assessment of patients with right brain damage may contribute to the identification of different executive function impairments in this sample.

Effect of aneurysmal subarachnoid hemorrhage on word generation

Background. Aneurysmal subarachnoid hemorrhage (aSAH) survivors commonly exhibit impairment on phonemic and semantic fluency tests; however, it is unclear which of the contributing cognitive processes are compromised in aSAH patients. One method of disentangling these processes is to compare initial word production, which is a rapid, semiautomatic, frontal-executive process, and late phase word production, which is dependent on more effortful retrieval and lexical size and requires a more distributed neural network. Methods. Seventy-two individuals with aSAH and twenty-five control subjects were tested on a cognitive battery including the phonemic and semantic fluency task. Demographic and clinical information was also collected. Results. Compared to control subjects, patients with aSAH were treated by clipping and those with multiple aneurysms were impaired across the duration of the phonemic test. Among patients treated by coiling, those with anterior communicating artery aneurysms or a neurological complication (intraventricular hemorrhage, vasospasm, and edema) showed worse output only in the last 45 seconds of the phonemic test. Patients performed comparably to control subjects on the semantic test. Conclusions. These results support a “diffuse damage” hypothesis of aSAH, indicated by late phase phonemic fluency impairment. Overall, the phonemic and semantic tests represent a viable, rapid clinical screening tool in the postoperative assessment of patients with aSAH.

A comparison of phenylketonuria with attention deficit hyperactivity disorder: do markedly different aetiologies deliver common phenotypes?

Phenylketonuria (PKU) is a well-defined metabolic disorder arising from a mutation that disrupts phenylalanine metabolism and so produces a variety of neural changes indirectly. Severe cognitive impairment can be prevented by dietary treatment; however, residual symptoms may be reported. These residual symptoms appear to overlap a more prevalent childhood disorder: Attention Deficit/Hyperactivity Disorder (ADHD). However, the aetiology of ADHD is a vast contrast to PKU: it seems to arise from a complex combination of genes; and it has a substantial environmental component. We ask whether these two disorders result from two vastly different genotypes that converge on a specific core phenotype that includes similar dysfunctions of Gray's (Gray, 1982) Behavioural Inhibition System (BIS), coupled with other disorder-specific dysfunctions. If so, we believe comparison of the commonalities will allow greater understanding of the neuropsychology of both disorders. We review in detail the aetiology, treatment, neural pathology, cognitive deficits and electrophysiological abnormalities of PKU; and compare this with selected directly matching aspects of ADHD. The biochemical and neural pathologies of PKU and ADHD are quite distinct in their causes and detail; but they result in the disorder in the brain of large amino acid levels, dopamine and white matter that are very similar and could explain the overlap of symptoms within and between the PKU and ADHD spectra. The common deficits affect visual function, motor function, attention, working memory, planning, and inhibition. For each of PKU and ADHD separately, a subset of deficits has been attributed to a primary dysfunction of behavioural inhibition. In the case of ADHD (excluding the inattentive subtype) this has been proposed to involve a specific failure of the BIS; and we suggest that this is also true of PKU. This accounts for a substantial proportion of the parallels in the superficial symptoms of both disorders and we see this as linked to prefrontal, rather than more general, dysfunction of the BIS.

Verbal fluency in children with ADHD: strategy using and temporal properties

Verbal fluency tasks are commonly used in cognitive and developmental neuropsychology in assessing executive functions, language skills as well as divergent thinking. Twenty-two typically developing children and 22 children with ADHD between the ages of 8 and 12 years were examined using verbal fluency tasks, prepotent response inhibition, and working memory tests. The clinical group showed impaired inhibitory and spatial working memory processes. We used different qualitative analyses of verbal fluency tasks to explore the lexical and executive strategies (word clustering and switching), and the temporal properties of the responses. Children with ADHD had a leeway in applying relevant lexical or executive strategies related to difficulties in strategy using. The reduced efficiency of children with ADHD in semantic fluency task is based on suboptimal shifting between word clusters and is related to the lack of ability of producing new clusters of items. The group difference appeared at the level of accessing and/or activating common words; however, the executive process of searching the lexicon extensively is intact.

Executive function profile of Chinese boys with attention-deficit hyperactivity disorder: different subtypes and comorbidity

This study examined the executive function (EF) profile of Chinese boys with attention-deficit hyperactivity disorder (ADHD) using a large sample. Executive function performance within the ADHD subtypes and the effects of comorbidity were also investigated. Five hundred Chinese boys (375 with ADHD and 125 controls) aged 6-15 completed a battery of EF tests. Boys with all types of ADHD performed worse in all of the EF tests than age- and intelligence quotient-matched healthy controls. The boys with the inattention ADHD subtype and the combined subtype showed similar impairments across different EF tasks, whereas the boys with the hyperactive-impulsive ADHD subtype primarily displayed deficits in theory of mind and visual memory. Comorbid oppositional defiant disorder/conduct disorder had no additional influence on the EF characteristics of the boys with ADHD only, whereas comorbid learning disorder increased the severity of inhibition and shifting impairments.

The influence of 5-HTT and COMT genotypes on verbal fluency in ecstasy users

Deficits in verbal fluency associated with ecstasy use have been well established; however, the mechanisms underlying this impairment have yet to be elucidated. In this study we investigated for the first time whether there was a disproportionate impairment in two cognitive subcomponents of verbal fluency: clustering (ability to generate words within the same subcategory) and switching (ability to change the subcategory). We also investigated a possible association between ecstasy use and verbal fluency in subjects genotyped for 5-HTT (5-HTTLPR and 5-HTTVNTR) and COMT (val(108/158)met, rs165599 and rs2097603) polymorphisms, in order to find a potential implication of genetic factors. Ecstasy polydrug users (n = 30) and non-ecstasy users (n = 41) were evaluated in both semantic and phonemic fluency. Results showed that ecstasy users had poorer semantic (but not phonemic) fluency performance than controls. Detailed analysis of clustering and switching performance revealed that this impairment was associated with poorer clustering mechanisms. Clustering was also modulated by the COMT rs165599 polymorphism independently of the group. A specific effect of the 5-HTTLPR polymorphism on switching performance was also found, with ss carriers performing significantly worse than ls and ll carriers, suggesting a serotonin modulation of frontal-executive flexibility. Based on the impaired clustering and switching strategies observed in ecstasy users, it might be proposed that both semantic knowledge and retrieval are impaired in this population. The verbal fluency deficit in ecstasy users may be attributable to a disruption of frontal-striatal circuits directly related with the serotonin function as well as a depletion of lexical-semantic stores mediated by temporal structures.

Developmental changes in semantic verbal fluency: analyses of word productivity as a function of time, clustering, and switching

We investigated age-related improvement in semantic category verbal fluency (VF) in 309 Dutch schoolchildren attending first to ninth grade. Quantitative analyses of number of correct responses as a function of time as well as qualitative analyses of clustering and switching were conducted. Overall, Dutch VF task performance, i.e., number of correct responses over 60 seconds, was not established before mid-adolescence. This is in line with previously published studies, using VF number of correct responses over 60 seconds as the main outcome measure and examining VF task performance across other cultures and languages (e.g., Italian, French, Hebrew). Next, mean cluster size, a measure of lexico-semantic knowledge, was not established until at least grade 3. In contrast, performance on the VF outcome measures "number of switches/clusters" was established at least 4 years later. Qualitative and quantitative Design Fluency (DF) outcome measures support the notion that the numbers of switches/clusters are valid measures of higher order cognitive functions, such as strategy use and cognitive flexibility. In line of this, VF number of correct responses during 16-60 seconds, a measure of controlled information processing, is established at least 2 years later (i.e., grades 7-8) than number of correct responses during the first 15 seconds time slide, a measure of automatic processing. Finally, environment, i.e., the level of parental education, primarily affected automatic and lexico-semantic knowledge. No effects of sex on VF performance were found. These data suggest that the alternative scoring methods of VF tasks can be used to acquire knowledge on development of lower and higher order cognitive functions in healthy children and the influence of the environment on it.

Speed of language comprehension is impaired in ADHD

OBJECTIVE

Children with ADHD have an increased risk of poor academic performance. It is important to identify cognitive processes that may be related to this academic failure. In Western schooling systems, especially language processing skills may be of relevance. The present study, therefore, compares the ability to comprehend complex sentences of individuals with and without ADHD.

METHOD

Fifteen children (aged 8-11) and 15 adolescents (aged 12-16) with ADHD combined subtype are matched for age, gender, and parental level of education to 30 control subjects. Language comprehension is measured using the neuropsychological procedure proposed by Luria and an adapted version of the Token Test.

RESULTS

Compared with the control group, children and adolescents with ADHD perform significantly slower on language comprehension tasks. Differences in accuracy are limited. No interaction between age and ADHD is found.

CONCLUSIONS

Children and adolescents with ADHD are slower and less efficient than matched control subjects with regard to complex sentence comprehension.

Comorbidity study of ADHD: applying association rule mining (ARM) to National Health Insurance Database of Taiwan

OBJECTIVE

This paper intends to apply association rule mining (ARM) to explore the labyrinthian network of ADHD comorbidity, and to examine the practicality of ARM in comorbidity studies using clinic databases.

METHODS

From clinic records of enrollees of Taiwan National Health Insurance (NHI), 18,321 youngsters aged 18 or less with diagnosis of ADHD in 2001 were recruited as case group in this study. And all their clinic diagnoses made from 2000 to 2002, as comorbidity, were categorized according to "The International Classification of Disease, 9th Revision, Clinical Modification" (ICD-9-CM) diagnosis system. For comparison, fourfold non-ADHD controls were recruited from 2001s NHI enrollees on a random base but matched gender and age of cases. ARM was done with Apriori algorithm to examine the strengths of associations among those diagnoses. The support and confidence values of ARM results were examined. Comorbidity rates and relative risk (RR) ratios of both groups of each diagnosis were compared one another.

RESULTS

ADHD case group has apparently higher risk of comorbidity with psychiatric comorbidity than with other physical illnesses. From results of ARM, developmental delay (DD) appears as an important node between ADHD and anxiety disorder (support: 5.12%, confidence: 97.42%), mild mental retardation (support: 4.42%, confidence: 92.09%) and autism (support: 6.49%, confidence: 94.93%).

CONCLUSIONS

The finding of this study, an important role of DD between ADHD and other psychiatric comorbidity, supports neurological findings in developmental delay of ADHD children's front cortex, as well as some epidemiology findings. This study also demonstrated the practicality of ARM in comorbidity studies using enormous clinic databases like NHIRD.