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.     

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.     

Category knowledge in Alzheimer's disease: normal organization and a general retrieval deficit.

Three hypotheses that could account for deficits in the retrieval of category information in Alzheimer's disease (AD) were evaluated: abnormal organization, class- or category-specific vulnerability, and limitation by general factors, such as decreased processing speed. Relative to 18 elderly control subjects, 18 patients with AD produced fewer items in a category fluency task and had longer reaction times in a category decision task. The pattern of performance across categories on both tasks was normal in the AD group: The same categories elicited the most (or fastest) responses in both the control group and the AD group. AD patients showed normal performance in ranking of category exemplars by typicality. There was no evidence for differential accessibility by category or by class of information (animate vs. inanimate). The authors conclude that a general factor or factors limit(s) retrievability equally across all categories.     

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.     

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.     

Influences of preclinical dementia and impending death on the magnitude of age-related cognitive deficits

The authors examined the influence of preclinical dementia and impending death on the cross-sectional relationship between age and performance in tasks assessing episodic memory, visuospatial skill, and verbal fluency. Increasing age was associated with a general decrease in cognitive performance. In addition, those who were to be diagnosed with dementia or had died by a 3-year follow-up, were older, and performed at a lower level than the remaining sample across all cognitive tasks at baseline. Nevertheless, removal of the preclinical dementia and impending death groups from the original sample affected the cross-sectional age-cognition relations relatively little. This pattern of findings suggests that the biological aging process exerts negative influences on cognitive functioning beyond those resulting from disease and mortality.     

Interacting effects of age and time of day on verbal fluency performance and intraindividual variability

We explored the effects of age and time of day (TOD) on verbal fluency ability with respect to performance level and intraindividual variability (IIV). Verbal fluency, which involves complex cognitive operations, was examined in 20 older (mean age = 72.8 years) and 20 younger (mean age = 24.2 years) adults with test start time alternating between morning and evening across four days. Older adults generated more words in the morning and younger adults more in the evening, corresponding with self-report peak TOD. Age by TOD interactions were also observed across fluency tasks on the number of switches among subcategory exemplars during word generation and on the IIV observed in switching behavior. Older adults exhibited greater variability in switching in the evening than in the morning, whereas younger adults showed the opposite pattern. These findings demonstrate that processes involving energization (initiating and sustaining) and attentional control may be particularly sensitive to age differences in TOD influences on cognition.     

The Spider Phobia Card Sorting Test: An investigation of phobic fear and executive functioning

Recent studies indicate that anxious participants show cognitive biases favouring threat‐related stimuli. However, most of this evidence comes from Stroop tasks, which are believed to tap a narrow range of executive skills. The current study investigated phobic fear and cognitive biases using tasks designed to tap a wider range of executive processes: the standard Wisconsin Card Sorting Test (WCST; Heaton, 1981), a modified version that included emotionally salient pictorial stimuli; the Spider Phobia Card Sorting Test (SPCST); and an emotionally valenced version of a verbal fluency task (VF). A total of 80 female participants (38 lower and 42 higher scorers on the Spider Phobia Questionnaire; SPQ) drawn from a larger sample of 126 completed either the standard WCST or the SPCST, the VF, and several mood measures. On the card sort, the higher SPQ SPCST group showed a significantly lower proportion of conceptual level responses, required a greater number of trials to complete the first category, and sorted significantly fewer stimulus cards to the spider target card than the lower SPQ SPCST group, or than either of the groups in the WCST condition who sorted to neutral target cards. On the VF, the higher SPQ group generated significantly more exemplars to the category “spiders” than the lower SPQ group. Therefore, fearful participants seemed to avoid or neglect the spider cue on the card sort, but performed better in generating “spiders” exemplars on the VF, as compared to the nonfearful group. Implications and limitations of these findings are discussed.     

Monitoring the Changing Status of Semantic Memory in Alzheimer's Disease: An Evaluation of Several Process Measures

The deficits in generating correct words on verbal fluency tasks exhibited by patients with Alzheimer's disease (AD) are accompanied by fewer switching responses, smaller phonemic and semantic cluster sizes, and greater than normal percentages of errors and category labels. On category fluency tasks, patients generate a greater proportion of words that are prototypical of their semantic class. To determine whether any of these supplementary measures of verbal fluency performance might be useful in revealing processes involved in the decline of semantic memory in AD, we studied 219 patients with AD and 115 elderly control participants longitudinally. Previously reported group differences between patients and controls were replicated, but changes in average cluster size, error rates, and prototypicality were not related to changes in overall severity of dementia and test-retest stability was only modest. The change in the percentage of labels generated on the Supermarket task was related to changes in dementia severity, but test-retest stability on this measure was quite low. All of these process measures appear to reflect only the current status of the patient's attention to the task and access to semantic knowledge, but they do not forecast future performance. The numbers of switching responses on the fluency tasks were sensitive to differences between clinically deteriorated and clinically stable patients and showed fairly high test-retest stability. However, the number of switching responses is so highly correlated with the number of correct words that it contributes little to the understanding of the processes involved in the progressive decline in performance on fluency tasks by patients with AD.     

注意控制和短时存储对音位流畅性和语义流畅性的影响

工作记忆的中央执行系统具有注意控制和短时存储的功能。采用双任务范式,探讨了中央执行系统的注意控制和短时存储对言语流畅性的影响。实验1考察了中央执行系统的转换和抑制功能对音位流畅性和语义言语流畅性的影响。结果表明,中央执行系统的转换和抑制功能对两种言语流畅性的影响相当。实验2考察了中央执行系统的注意控制资源和短时存储资源对两种言语流畅性的影响。结果表明,语义流畅性更依赖于短时存储资源,音位流畅性更依赖于注意控制资源。研究还发现,被试完成语义流畅性任务的策略更易受概念系统的特性影响,完成音位流畅性任务的策略更易受语言的特点影响。在实验研究的基础上,作者提出了工作记忆影响言语流畅性的理论模型     

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.     

A longitudinal study of the performance of the elderly and young on the Tower of Hanoi puzzle and Rey recall

Normal performance on the Tower of Hanoi puzzle by amnesic patients has been taken as support for viewing this problem solving task as having a nondeclarative memory component. Individuals in each decade of life between the 20s and 80s were asked to solve this puzzle four times in four sessions with intersession intervals from 1 to 7 days (Davis & Keller, 1998). Participants in their 70s and 80s were significantly impaired compared to participants in their 20s and 30s. The elderly were also significantly impaired on five immediate trials of a 15 words verbal recall test. Participants were readministered these tests an average of 6.6 years later for the elderly (n = 12) and 7.7 years later for the young (n = 11). For the Tower of Hanoi, the performance of the elderly, but not the young individuals, was significantly poorer than their original performance. For the verbal recall test, no significant change over time was detected for the young or elderly participants. These findings support the view that some nondeclarative and/or problem solving tasks demonstrate as great or greater decline with age than some declarative tasks.     

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.     

Behavior analysis in instructional design: A functional typology of verbal tasks

This paper describes and illustrates a typology of verbal instructional tasks for advanced classroom instruction and inservice training. The typology is based upon functional definitions of elementary and conceptual behavior, and incorporates the kinds of goals and objectives that surveys and research have shown to be important for experienced learners. The typology's metastructure is B. F. Skinner's (1957) verbal behavior classification system. This paper describes Skinner's system as a context for understanding and selecting instructional tasks for experienced learners. This paper also discusses rate of response as an important dimension of proficiency or mastery, and procedures for selecting proficiency criteria of tasks in the typology are also described. Results of the first of a series of validation studies indicated that high agreement between typology designer and subjects' classification of tasks can be attained after a short training session. The typology is discussed as a vehicle for standardizing instructional research and practice, and as a basis for research on transfer of control across classes of verbal behavior. Implications for research on building fluency of adult performance, and efficiency in instructional design are also discussed.     

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.     

Category and letter fluency in semantic dementia, primary progressive aphasia, and Alzheimer's disease

This study examined the impact of various degenerative dementias on access to semantic knowledge and the status of semantic representations. Patients with semantic dementia, primary progressive aphasia, and Alzheimer's disease were compared with elderly controls on tasks of category and letter fluency, with number of words generated, mean lexical frequency and errors recorded. The findings are consistent with the view that category and letter fluency rely on both common and unique cognitive processes. Fluency tasks, with the richness of data obtained, are valuable in distinguishing different dementia syndromes from one another.     

Perseveration in Normal Aging: A Comparison of Perseveration Rates on Design Fluency and Verbal Generative Tasks

Three generative tasks (design generation, animal naming, words starting with m) from the Cognitive Linguistic Quick Test were administered to 73 healthy individuals in four age groups (18–39, 40–59, 60–74, 75–88) and scored for perseveration and productivity. Perseveration rates for design generation were significantly higher, and increased linearly as a function of age. The number of individuals who perseverated at least once on design generation also increased linearly, with highest prevalence in the oldest group. No age effects were found for perseveration on the verbal naming tasks. Perseverations across tasks were independent of one another. The design generation task may require multiple simultaneous processing skills, placing more demand on compromised executive processing in the elderly.     

Typical intellectual engagement and cognition in the ninth decade of life: The Lothian Birth Cohort 1921

Investment traits-the tendency to seek out and engage in cognitive activity-might affect intellectual growth across the life span, specifically the development from fluid to crystallized intelligence. Here we explore how childhood IQ at age 11 years, IQ at age 79, and the investment trait Typical Intellectual Engagement (TIE) at age 81 affect the mean level and change in verbal fluency scores, used as an indicator of crystallized intelligence, across the ages 79, 83, and 87 in the Lothian Birth Cohort 1921 (maximum N = 569; Deary, Whiteman, Starr, Whalley, & Fox, 2004). A first latent growth model showed significant variance in the mean level of verbal fluency and significant decline in verbal fluency from age 79 to age 87. The rate of change was invariant across study participants in the Lothian Birth Cohort 1921. A second model found that IQ at age 11 significantly predicted IQ at age 79 (β = .66; p < .001), which in turn predicted verbal fluency and TIE in the ninth decade of life with standardized path parameters of .46 and .15 (p < .001), respectively. TIE had a significant association with verbal fluency (β = .14, p = .002); together, IQ at age 11 and 79 and TIE accounted for 25.5% of the variance in verbal fluency. A final model identified the TIE subfactor of intellectual curiosity as a significant mediator of the effect of IQ on verbal fluency; the TIE subfactors abstract thinking, reading, and problem solving showed no significant associations. In summary, TIE-in particular, intellectual curiosity-significantly mediated the effects of IQ on crystallized intelligence in old age. Because there was no significant between-subjects variance in verbal fluency trajectories in the current study, neither TIE nor IQ were associated with individual differences in cognitive decline. (PsycINFO Database Record (c) 2012 APA, all rights reserved).