More expertise for a better perspective: Task and strategy-driven adaptive neurofunctional reorganization for word production in high-performing older adults

The suggestion that neurofunctional reorganization may contribute to preserved language abilities is still emerging in aging studies. Some of these abilities, such as verbal fluency (VF), are not unitary but instead rely on different strategic processes that are differentially changed with age. Younger (n = 13) and older adults (n = 13) carried out an overt self-paced semantic and orthographic VF tasks within mixed fMRI design. Our results suggest that patterns of brain activation sustaining equivalent performances could be underpinned by different strategies facing brain changes during healthy aging. These main findings suggest that temporally mediated semantic clustering and frontally mediated orthographic switching were driven by evolutive neurofunctional resources in high-performing older adults. These age-related activation changes can appear to be compatible with the idea that unique neural patterns expressing distinctive cognitive strategies are necessary to support older adults’ performance on VF tasks.     

Sex differences in cognition in healthy elderly individuals

ABSTRACT

Sex differences in patterns of cognitive test performance have been attributed to factors, such as sex hormones or sexual dimorphisms in brain structure, that change with normal aging. The current study examined sex differences in patterns of cognitive test performance in healthy elderly individuals. Cognitive test scores of 957 men and women (age 67–89), matched for overall level of cognitive test performance, age, education, and depression scale score, were compared. Men and women were indistinguishable on tests of auditory divided attention, category fluency, and executive functioning. In contrast, women performed better than men on tests of psychomotor speed and verbal learning and memory, whereas men outperformed women on tests of visuoconstruction and visual perception. Our finding that the pattern of sex differences in cognition observed in young adults is observed in old age has implications for future studies of both healthy elderly individuals and of those with cognitive disorders.     

Verbal Knowledge as a Compensation Determinant of Adult Age Differences in Verbal Fluency Tasks over Time

The aim of this study was to determine whether verbal knowledge can compensate for the age-related decline in word production during a fluency test. We assessed the performance of 20 young and 20 old subjects in standard letter and semantic fluency tasks over time (T1: 0–30 s vs. T2: 31–60 s). The number of words produced, switching, and clustering components (Troyer et al. Neuropsychology, 11(1): 138–146, 1997) were investigated. Correlations between age and cognitive factors (processing speed, executive functions, and vocabulary level) were analyzed. The results revealed a knowledge compensation mechanism in elderly subjects, but only in letter fluency productions. It only occurred during the second period and was related to an increase in the clustering component and a positive correlation between age and vocabulary level. The differences between letter and semantic fluency performances are discussed in terms of the nature of the non-semantic and semantic components involved in these tasks.     

Increasing Levels of Semantic Verbal Fluency in Elderly English Adults

ABSTRACT

Analyses incorporating large independent population-based samples and identical measures are needed to investigate recent trends in cognitive function. Nationally representative independent cohorts of community living individuals in England aged 65 years or older from the MRC Cognitive Function and Ageing Study in 1991 (n = 9458) and the English Longitudinal Study of Ageing in 2002 (n = 5196) were compared. East Cambridgeshire participants aged 65–69 years in 1991 (n = 680) were also compared to an independent cohort examined in 1996 (n = 600). Semantic verbal fluency, as measured by the animal naming neuropsychological test, increased by 1.1 extra words a minute in England between 1991 and 2002 (95% CI 0.9, 1.3). A similar increase was also observed in East Cambridgeshire. Levels of semantic verbal fluency appear to have increased in the older English population, which may help to buffer the aging population from future increases in dementia.     

Word fluency performance and strategies in children with cochlear implants: age‐dependent effects?

Löfkvist, U., Almkvist, O., Lyxell, B. & Tallberg, I.‐M. (2012). Word fluency performance and strategies in children with cochlear implants: age‐dependent effects? Scandinavian Journal of Psychology 53, 467–474. Word fluency was examined in 73 Swedish children aged 6–9 years divided into two age groups, 6–7 and 8–9 years; 34 deaf children with cochlear implants (CI) (15 girls/19 boys) and 39 age‐matched children with normal hearing (NH) (20 girls/19 boys). One purpose was to compare the ability to retrieve words in two different word fluency tasks; one phonemically based (FAS letter fluency) and one semantically based (animal fluency). A second purpose was to examine retrieval strategies in the two tasks by conducting an analysis of clustering and switching of word sequences. In general we found that age was an important factor for word fluency ability, in both the CI and the NH groups. It was also demonstrated that children with CI aged 8–9 years retrieved significantly fewer words and used less efficient strategies in the retrieval process, especially on the phonemically based task compared to children with NH of the same ages, whereas children 6–7 years performed similarly in both groups regarding number of retrieved words and use of strategies. The results are discussed with respect to factors such as age differences in performance for children with CI, especially for the phonemically based task.     

Level of Education and Category Fluency Task among Spanish Speaking Elders: Number of Words,Clustering, and Switching Strategies

ABSTRACT

It has been well documented that education influences the individual's performance on category fluency tasks but it is still unclear how this effect may differ across the different types of category tasks (i.e., animals, fruits, vegetables and clothing). This study aims (1) to analyze the effect of the level of education on four different types of category fluency tasks among elder Hispanic Americans and (2) to provide normative information on a population with different education levels that was previously screened for neurological and psychiatric conditions. In addition this study examines the semantic strategies used by these individuals to complete the fluency tasks. The sample included 105 healthy Hispanic individuals (age 55–98; 29 males and 76 females) divided into three education groups (<6, 6–11 and >11 years of education). Results showed that after controlling for age and gender, education has a main effect and is a strong predictor of performance in verbal fluency for the categories animals and clothing with increasing educational attainment being associated with higher category fluency scores and with more switches between categories. These findings suggest that the category fruit is less influenced by level of education than the other three semantic categories and may be a more appropriate test across different educational groups. Results from this study provide a reference for clinicians assessing verbal fluency in Spanish speaking populations.     

Sex differences in verbal fluency: the role of strategies and instructions

Sex differences in verbal fluency performance and strategies are highly controversial, nevertheless suggesting a slight female advantage at least for phonemic fluency. A tendency of increased clustering of words into phonemic and semantic subcategories in men and increased switching between those categories in women has been suggested. In spatial tasks, it has been demonstrated that changes in instructions favoring a certain cognitive strategy can alter sex differences in performance. Such an approach has, however, not been attempted previously with verbal tasks. In the present investigation, 19 women in their luteal cycle phase and 23 men performed a phonemic and a semantic fluency task with three different instructions, one neutral, one emphasizing the clustering, and one emphasizing the switching of words. While under neutral instructions no sex differences were observed in verbal fluency performance and strategies, sex differences in switching and overall performance were observed in semantic fluency with an instruction requiring a switching strategy. Furthermore, correlation analyses suggested that the importance of strategies for overall performance differed between women and men. While only switching, but not clustering was related to overall verbal fluency performance in all tasks under all instructions, this relationship was driven by women in the phonemic task, but by men in the semantic task. These results highlight the importance of a consistent methodology in sex difference research. Slight variations in instructions may in part explain inconsistencies regarding sex differences in verbal fluency between previous studies.     

Qualitative analysis of verbal fluency output: review and comparison of several scoring methods

We compared three approaches to scoring qualitative aspects of verbal fluency performance in 88 healthy young adults. Phonemic and semantic fluency output was scored for word clustering and switching between clusters. Convergent validity analyses using other tests presumed to tap into strategy use (California Verbal Learning Test, Ruff Figural Fluency Test) support scoring of phonemic and semantic clusters on both fluency tasks. Task-discrepant clustering (e.g., semantic clustering on phonemic fluency) may index intentional strategy use on both fluency tasks, whereas task consistent clustering (e.g., phonemic clustering on phonemic fluency) appears strategic only on semantic fluency. Switching can be decomposed into subtypes that appear to reflect different cognitive processes on phonemic versus semantic fluency. Principal components analyses suggest that earlier scoring methods do not fully capture the "process" aspects of verbal fluency performance.     

Children's word fluency strategies

Two word fluency tasks, the FAS letter fluency task and the "animal" semantic fluency task, were administered to 130 healthy Swedish-speaking children between 6 and 15 years of age. The main aim was to gather normative data on these word fluency tasks for Swedish-speaking children. Another purpose was to examine the switching and clustering strategies used, along with the occurrence of erroneous responses, in relation to demographic data and number of words retrieved. Both phonological and semantic analyses of switching and clustering were conducted. Higher age was found to be related to a more effective use of phonological and semantic switching and clustering strategies. The reference data resulting from this study may be of clinical value in examinations of children with various diagnoses, including language impairment.     

Verbal fluency output in children aged 7-16 as a function of the production criterion: qualitative analysis of clustering, switching processes, and semantic network exploitation

Developmental changes in children's verbal fluency were explored in this study. One hundred and forty children aged from 7 to 16 completed four verbal fluency tasks, each with a different the production criterion (letter, sound, semantic, and free). The age differences were analyzed both in terms of number of words produced, and clustering, switching, and semantic network exploration. Analysis of the number of words produced showed a larger difference between the 7-8- and the 9-10-year-olds in semantic than in letter fluency, but this difference gradually disappeared with increasing age for semantic fluency while remaining constant for letter fluency. In letter fluency production, age modified both the number of switches and clusters formed whereas in semantic fluency tasks, only cluster size changed with age. Concerning the semantic network exploration indicators derived from the supermarket fluency task, the number of categories sampled increased from 11 to 12 years, but efficient semantic exploitation occurred only after the age of 13-14 years. These results are discussed in terms of the development of strategic retrieval components and categorical knowledge.     

Influence of depression on verbal fluency performance

Abstract

Neuropsychologists are often faced with the challenge of assessing older adults who exhibit both cognitive deficits and symptoms of depression. This study examined factors associated with diminished fluency in elderly adults. Three groups were tested: 54 community elderly, 35 institutionalized elderly, and 40 young adults using the Controlled Oral Word Association test. Significant incremental contributions to performance on verbal fluency included age, education, depression, and the interaction term for depression and functional impairment. Diminished verbal fluency was associated with depression among older adults who were not functionally impaired. the results suggest that variables other than cerebral integrity must be taken into consideration when interpreting older adults' performance on fluency tests.     

Age-related differences in word-retrieval but not in meaning generation

ABSTRACT

This study examines age-associated changes in retrieval on a picture-naming task, phonemic and semantic fluency tasks, and the Homophone Meaning Generation Test (HMGT). The sample included 152 Hebrew-speaking adults, half young (mean age 22.75) and half old (mean age 76.05). Groups differed on the picture-naming task and on both verbal fluency tasks, but not on the HMGT. Age explained a greater share of the variance than did education level on these three tests, whereas the opposite pattern of results was seen on the HMGT. We suggest that age-related word finding difficulties are attenuated when performance allows for semantic rather than phonological access.     

Delayed reconfiguration of a non-emotional task set through reactivation of an emotional task set in task switching: an ageing study

ABSTRACT

In our everyday life, we frequently switch between different tasks, a faculty that changes with age. However, it is still not understood how emotion impacts on age-related changes in task switching. Using faces with emotional and neutral expressions, Experiment 1 investigated younger (n?=?29; 18–38 years old) and older adults’ (n?=?32; 61–80 years old) ability to switch between an emotional and a non-emotional task (i.e. responding to the face's expression vs. age). In Experiment 2, younger and older adults also viewed emotional and neutral faces, but switched between two non-emotional tasks (i.e. responding to the face's age vs. gender). Data from Experiment 1 demonstrated that switching from an emotional to a non-emotional task was slower when the expression of the new face was emotional rather than neutral. This impairment was observed in both age groups. In contrast, Experiment 2 revealed that neither younger nor older adults were affected by block-wise irrelevant emotion when switching between two non-emotional tasks. Overall, the findings suggest that task-irrelevant emotion can impair task switching through reactivation of the competing emotional task set. They also suggest that this effect and the ability to shield task-switching performance from block-wise irrelevant emotion are preserved in ageing.     

The effects of second-language acquisition on verbal fluency among elderly israelis

The present study investigated the effect of age of second-language acquisition (Hebrew) on verbal fluency in a random sample of 196 elderly Israelis from four distinct ethnic groups. Using conventional statistics, it was shown that phonemic fluency, particularly switching, is associated with education and the age of Hebrew acquisition, while semantic fluency, particularly clustering, is associated with age. Ethnic differences were not significant after controlling for the age of Hebrew acquisition and education. Additional analyses show that the tendency of subjects to use borrowed, non-Hebrew words on the phonemic fluency task was associated with lower total scores on this task and later age of Hebrew acquisition. In contrast, the tendency to use non-Hebrew words on the semantic fluency task was associated with age and higher total scores. These findings are discussed with regard to recent functional imaging studies of bilingual subjects. Such findings indicate that native and second languages form distinct areas of activation in the dominant anterior language area, an area often associated with phonemic processing and switching, whereas an overlap of activation of various languages has been demonstrated within the posterior language areas, those that are often associated with semantic processing.     

A test of the CaR-FA-X mechanisms and depression in adolescents

ABSTRACT

People who have depression have difficulty recalling specific autobiographical information (Sumner, (2011) The mechanisms underlying overgeneral autobiographical memory: An evaluative review of evidence for the Ca R-FA-X model. Clinical Psychology Review, 3231(1), 34–48). This is called overgeneral autobiographical memory (OGM) and is associated with the development and persistence of depression. Williams, Barnhofer, Crane, Hermans, Raes, Watkins, & Dalgleish (2007 Autobiographical memory specificity and emotional disorder. Psychological Bulletin, 133(1), 122–148) proposed that OGM is maintained by three mechanisms: capture and rumination (CaR), functional avoidance (FA), and impaired executive control (X), and integrated these into the CaR-FA-X model. The aim of this study was to assess OGM and test the CaR-FA-X model in adolescents with low mood. We recruited 29 young people aged 12–17 with elevated symptoms of depression and 29 with minimal symptoms of depression, matched for gender and age. After controlling for IQ, adolescents with elevated depression retrieved fewer specific memories, ruminated more, and had poorer working memory and verbal fluency than adolescents with minimal depression. The groups did not differ on measures of inhibition or functional avoidance. The CaR-FA-X model was therefore partially supported. These results confirm that there is a relationship between low mood and OGM in young people and that OGM may arise as consequence of impaired working memory and verbal fluency and cognitive interference due to rumination.     

The influence of age and gender on ultra-rapid categorization

ABSTRACT

In ultra-rapid categorization studies, population-level reaction time differences in performance are consistently reported. In a previous study, we replicated these findings and also observed consistent gender differences in young adults (18–24 years old). We now tested a group of adolescents (11–16 years old) on the same ultra-rapid categorization tasks. Results indicated that age had a significant impact on categorization performance. Although women outperformed men during adulthood, this effect reversed in adolescence (boys faster than girls). This gender x age interaction for categorizing meaningful (non-)social visual scenes could be caused by gender-specific development processes underlying emotion regulation strategies and/or context sensitivity.     

Age-related changes in processing speed modulate context use during idiomatic ambiguity resolution

ABSTRACT

The goal of the current study was to investigate whether age-related changes in processing speed, as indexed by verbal fluency, modulate context use in the resolution of ambiguous idioms (e.g., tie the knot). Younger and older adults completed a cross-modal priming experiment where they decided whether visual word targets were related in meaning to idiomatically or literally biased auditory sentence primes. Older adults with high verbal fluency, similar to younger adults, showed context-dependent facilitation in both biasing sentence contexts. In contrast, older adults with low verbal fluency did not show facilitation of literal meanings in literally biased sentence contexts, likely because they had difficultly inhibiting the dominant figurative meaning. These findings argue that age-related changes in context use during ambiguity resolution are restricted to older adults with reduced processing speed. The results also suggest that verbal fluency may reflect the speed in recruiting frontally-mediated selection mechanisms during ambiguity resolution.     

Performance on a measure of category fluency in cognitively impaired elderly

ABSTRACT

Measures of verbal fluency are widely used in the assessment of cognitive functioning of the elderly. However, limited research has evaluated patterns (across specific timed intervals) of performance on tasks of language fluency in different forms of dementia. The current study investigated semantic fluency in 488 elderly individuals (249 with Alzheimer's dementia, 97 Vascular dementia, 97 Mild Cognitive Impairment and 45 cognitively intact) across 15-second intervals in an animal naming task using retrospective chart review. Normal controls produced significantly more exemplars and AD patients produced fewer animal names than the other groups. After the first 15- second time interval, the demented groups produced significantly fewer exemplars than the non-demented. At the end of 30 seconds it was possible to differentiate normal aging from MCI who no longer differed from the VaD group. Overall, it appears that the greatest and most clinically meaningful differences between the diagnostic groups were detected in the first three 15-second intervals. The present findings support the use of time intervals and total scores on tasks of verbal fluency in clinical settings and for research purposes.     

Differential impacts of age of acquisition on letter and semantic fluency in Alzheimer's disease patients and healthy older adults

The degree to which the typical age of acquisition (AoA) of words and word frequency have separable influences on verbal production tasks has been strongly debated. To examine the overlap between these factors in verbal fluency tasks, the performance of Alzheimer's disease (AD) patients (N?=?34) and normal elderly controls (N?=?36) was compared on semantic (e.g., vegetables) and letter (e.g., words that begin with F) fluency tasks. These comparisons revealed that words generated for the semantic fluency task had an earlier AoA while words generated for the letter fluency task had a higher word frequency. Differences in AoA between AD patients and controls were larger for semantic than letter fluency. These results suggest that AoA has an effect on verbal production that is independent of word frequency and that AoA has a semantic locus.