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.     

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 and12 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.     

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.     

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.     

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.     

Clustering and switching in unconstrained,phonemic and semantic verbal fluency: the role of age and school type

We investigated the role of age and school type on clustering and switching in verbal fluency tasks (VFTs) with Brazilian children. The children were administered unconstrained, phonemic and semantic VFTs with a duration of 150 or 120 s, respectively. Both age and school type influenced all variables and in terms of performance over time. Older children and private school students outperformed the remainder of the sample, with the first 30 s of each VFT usually being the most productive. Although the size of the clusters produced did not differ between groups, the types of clusters did show some variations, with semantic clusters being the most frequent. Our results revealed strong correlations between switching ability and word production in all three VFTs. In conclusion, the executive functions known as planning and cognitive flexibility play a crucial role in word production by organising and facilitating the recall of lexical information from memory.     

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

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.     

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.     

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.     

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.     

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.     

The Effects of Age,Sex and Alzheimer's Disease on Strategy Use During Verbal Fluency Tasks

ABSTRACT

Clustering and switching strategies during phonemic and semantic verbal fluency tasks were investigated in healthy adults (n = 193, 86 males, 20–90 years) in young, middle-aged, young–old, and old–old age groups (Study 1). Older groups produced fewer total words and lower switching scores; males relied more on clustering and females on switching to produce equivalent output. In Study 2, early Alzheimer's disease participants, compared to healthy older adults, (n = 26 per group) produced fewer total words and smaller average clusters. Sex, age, and clinical differences on switching and clustering strategies support a dual processing model of verbal fluency.     

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.     

语音回路和视空间模板对音位流畅性和语义流畅性的影响

采用双任务范式,通过四种次任务考察了工作记忆两个子系统－语音回路和视空间模板对音位流畅性和语义流畅性的影响。实验1表明,主动产生系列发音和被动聆听声音判断对音位流畅性影响更大,表明音位流畅性更依赖于语音回路。实验2表明,字形匹配和字形旋转判断对语义流畅性影响更大,表明语义流畅性更依赖于视空间模板。研究还表明,被试完成音位流畅性任务的策略更易受语言的特点影响,完成语义流畅性任务的策略更易受概念系统的特性影响     

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

The performance of ADHD children on semantic category fluency (SCF) versus initial letter fluency (ILF) tasks was examined. For each participant, word production was recorded for each 15-s time slice on each task. Performance on both fluency tasks was compared to test the hypothesis that children with ADHD are characterized by a performance deficit on the ILF task because performance on this task is less automated than performance on the SCF. Children classified with ADHD (N = 20) were compared to children with other psychopathology (N = 118) and healthy controls (N = 130). Results indicated that the groups could not be differentiated by the total number of words produced in 60 s in either fluency task. As hypothesized, a significant interaction of group by productivity over time by type of fluency task was found: ADHD children had more problems finding words in the first 15 s of the IFL than did children in the other two groups, and as compared with their performance on the SCF. Results were taken to indicate that children with ADHD symptoms show a delay in the development of automating skills for processing abstract verbal information.     

Searching for the Right Word: Performance on Four Word-Retrieval Tasks Across Childhood

Word retrieval was assessed in 207 normally developing Hebrew-speaking children aged 8–17 through four tasks: picture naming, phonemic fluency, semantic fluency, and homophone meaning generation (HMGT). Scores on all tests correlated positively and significantly with participant age. Yet, age effects and the correlation between age and test scores were weakest for the naming test and strongest for the HMGT. We discuss the nature of the word search involved in each task and suggest that the more executive demands required by a test the steeper the slope of performance increase on this test.     

Verbal Fluency,Semantics, Context and Symptom Complexes in Schizophrenia

Lexical-semantic access and retrieval was examined in 15 adults diagnosed with schizophrenia and matched controls. This study extends the literature through the inclusion of multiple examinations of lexical-semantic production within the same patient group and through correlating performance on these tasks with various positive and negative clinical symptoms. On tasks of verbal fluency, meaning generation, sentence production using contextual information and confrontation naming, participants with schizophrenia made significantly more semantic errors on naming tasks; produced fewer meanings for homophones; produced fewer items on semantic, phonological, cued and switching fluency tasks; and produced more errors on sentence production tasks when compared to healthy controls. Significant correlations were also observed between ratings of psychomotor poverty and measures of semantic production and mental inflexibility. This study has provided additional evidence for deficits in lexical-semantic retrieval which are not due to underlying semantic store degradation, do not involve phonological based retrieval, and at the level of sentence generation appear to vary as a function of the contextual constraints provided.     

Pervasive influence of semantics in letter and category fluency: a multidimensional approach

We used multidimensional statistical procedures to study semantic and lexical processes underlying word retrieval in verbal-fluency performance. Forty healthy participants were given a two-choice letter task (i.e., generate items beginning with the letter 'A' or 'F', in any order) and a two-choice category task (i.e., generate animal or fruit names, in any order). Using correspondence analysis (CoA) and hierarchical clustering (HC), we found evidence of prominent semantic organization in both letter and category fluency. For example, a striking categorical segregation between animate and inanimate entities emerged during the letter task. Analysis of inter-item times revealed strong sequential priming effects in both tasks. Taken together, these results indicate that semantic facilitation is pervasive in word retrieval processes, even in the letter-fluency task, and therefore suggest that the traditional view of letter fluency as a purely phonemically based task should be revised. Finally, our findings may help explain patterns of verbal-fluency measures obtained in focal brain lesion patients.     

Phonological–semantic flexibility and its role in reading for Chinese kindergarten children

The present study aimed to examine the role of phonological–semantic flexibility (PSF) in learning to read Chinese. PSF refers to a specific flexibility applied to process the dual linguistic dimensions of words (i.e., sound and meaning). A correlational study (Study 1) was conducted to determine the unique contribution of PSF to three aspects of early reading abilities, including word reading accuracy, word reading fluency and reading comprehension. A total of 190 Chinese kindergarten children were tested on a PSF task and a range of cognitive, linguistic and reading tasks. Results of hierarchical regressions showed that PSF uniquely and significantly contributed to the reading abilities beyond the effects of established cognitive factors (IQ, working memory, inhibition control, and cognitive flexibility) and linguistic factors (syllable skills, morphological skill and vocabulary skill). In the second part, an intervention study (Study 2) was conducted in which two groups of kindergarten children received explicit training on PSF (27 children) and colour–shape flexibility (26 children) respectively. Children in the PSF group showed significantly more improvement in PSF and word reading fluency than the control group. Overall, the present study demonstrated the theoretical and practical importance of PSF for learning to read Chinese.     

Phonological sensitivity and memory in children with a foreign language learning difficulty

The phonological processing and memory skills of 12- and 13-year-old Italian children with difficulty in learning English as a foreign language (foreign language learning difficulty, FLLD) were examined and compared with those of a control group matched for age and nonverbal intelligence. Three experiments were conducted. A dissociation between verbal and visuo-spatial working memory was observed when compared to the control group; children with FLLD showed a poorer performance in a phonological working memory task but performed to a comparable level in a visuo-spatial working memory task (Experiment 1). In Experiment 2 the word length and the response modality of an auditory word span task were manipulated in order to examine the efficiency of the phonological loop and the relevance of the spoken output. The FLLD group did not show sensitivity to the word length effect and showed no advantage in the picture pointing recall condition. In Experiment 3 children with FLLD were shown to be sensitive to phonological similarity but again they showed neither a word length effect nor a slower articulation speed. Furthermore, in all three experiments children with FLLD were shown to be less efficient in phonological sensitivity tasks and this deficit appeared to be independent of the phonological memory problem. All three experiments consistently showed that children with FLLD have an impairment in phonological memory and phonological processing, which appear to be independent from one other but both contribute to the children's difficulty in learning a second language.