Why do older adults have difficulty with semantic fluency?

In Alzheimer’s dementia (AD), greater declines in semantic fluency (SF) relative to letter fluency (LF) have been assumed to reflect semantic disintegration. However, the same pattern is observed in typical aging and neurodegenerative disorders besides AD. We examined this assumption by comparing different aspects of SF and LF performance in older adults with and without dementia, and identifying which verbal fluency measures most clearly distinguish AD from typical aging. Verbal fluency data were compared from 109 individuals with AD and 66 typically aging adults. Correct items, clusters, and errors were analyzed using both raw counts and proportions. Regression analyses examined Task-by-Group interactions and the impact of demographic variables on verbal fluency measures. ROC analyses examined the sensitivity and specificity of the different outcome measures. In regressions, interactions were found for raw but not proportional data, indicating that different group patterns were driven largely by the number of correct items produced. Similarly, in ROC analyses, raw SF totals showed stronger discriminability between groups than either raw discrepancy scores (SF–LF) or discrepancy ratios (SF/LF). Age and cognitive status (MMSE) were the strongest individual predictors of performance. Findings suggest that AD entails quantitative declines in verbal fluency, but qualitatively similar patterns of performance relative to typically aging adults. Thus, SF declines in AD seem to be at least partially attributable to an exaggeration of the underlying mechanisms common to typical aging, and do not necessarily implicate semantic disintegration.

BackgroundEvidence is emerging that subtle language decline is an early indicator of Alzheimer’s disease (AD). This study assessed change in semantic and letter fluency in individuals with subjective cognitive decline (SCD), and examined whether trajectories differed between individuals with and without amyloid‐beta (Aβ)‐pathology.MethodLongitudinal data from 437 individuals of the memory clinic‐based Amsterdam Dementia Cohort were included (Age 61±8 years, 184(42%) Female, follow‐up time 5.3±3.7 years; Table 1). Participants were classified as SCD at baseline, had available baseline Aβ‐information and had at least 1 follow‐up on semantic or letter fluency. Baseline Aβ‐status was dichotomized as positive/negative based on local cut‐offs for Aβ1‐42 concentrations in cerebrospinal fluid, or visual inspection of amyloid positron emission tomography‐imaging (Florbetapir or PiB). Two linear mixed models (LMM) were used to investigate change on semantic and letter fluency. Models included time and time*Aβ‐status as predictors of interest, a random intercept for participant, and age, sex, education were adjusted for. LMMs were subsequently stratified for Aβ‐status.ResultAt baseline, the groups did not differ in semantic (p = 0.313) or letter fluency (p = 0.294). Over time Aβ‐positive individuals changed more rapidly on semantic fluency compared to Aβ‐negative individuals (β = ‐0.32,CI = ‐0.49 – ‐0.14;p<.001). The Aβ‐positive group declined with 0.35 words per year (CI = ‐0.49 – ‐0.20;p<.001), while Aβ‐negative individuals did not show change (β = 0.03;CI = ‐0.12 – 0.06;p = 0.496) (Figure 1). On letter fluency Aβ‐positive individuals changed differently compared to Aβ‐negative individuals (β = ‐0.38;CI = ‐0.72 – ‐0.04;p = 0.028), to the extent that the Aβ‐positive group did not progress (β = 0.10;CI = ‐0.21 – 0.41;p = 0.533), while Aβ‐negative individuals improved with 0.47 words per year (CI = 0.29 – 0.65;p<.001) (Figure 2).ConclusionOur results indicate that Aβ‐positive individuals decreased on semantic fluency, but remained stable on letter fluency. In contrast, Aβ‐negative individuals remained stable on semantic fluency, while they improved on letter fluency over time, which might suggest a learning effect. These findings suggest that the presence of Aβ‐pathology is characterized by semantic loss, highlighting the potential of language based performance as a biomarker for Aβ‐pathology in SCD.

The verbal fluency task is a widely used neuropsychological test of word retrieval efficiency. Both category fluency (e.g., list animals) and letter fluency (e.g., list words that begin with F) place demands on semantic memory and executive control functions. However, letter fluency places greater demands on executive control than on category fluency, making this task well suited to investigating potential bilingual advantages in word retrieval. Here we report analyses on the category and letter fluency for bilinguals and monolinguals at four ages, namely, 7-year-olds, 10-year-olds, young adults and older adults. Three main findings emerged: (1) verbal fluency performance improved from childhood to young adulthood and remained relatively stable in late adulthood; (2) beginning at 10-year-olds, the executive control requirements for letter fluency were less effortful for bilinguals than monolinguals, with a robust bilingual advantage on this task emerging in adulthood and (3) an interaction among factors showed that category fluency performance was influenced by both age and vocabulary knowledge, but letter fluency performance was influenced by bilingual status.

Sex differences in lateralization of semantic verbal fluency in temporal lobe epilepsy

The functional organization and related anatomy of executive functions are still largely unknown and were examined in the present study using a verbal fluency task. The objective of this study was to determine the cognitive architecture of a fluency task and related voxelwise anatomy in the GRECogVASC cohort and fMRI based meta-analytical data.First, we proposed a model of verbal fluency in which two control processes, lexico-semantic strategic search process and attention process, interact with semantic and lexico-phonological output processes. This model was assessed by testing 404 patients and 775 controls for semantic and letter fluency, naming, and processing speed (Trail Making test part A). Regression (R2 = .276 and .3, P = .0001, both) and structural equation modeling (CFI: .88, RMSEA: .2, SRMR: .1) analyses supported this model.Second, voxelwise lesion-symptom mapping and disconnectome analyses demonstrated fluency to be associated with left lesions of the pars opercularis, lenticular nucleus, insula, temporopolar region, and a large number of tracts. In addition, a single dissociation showed specific association of letter fluency with the pars triangularis of F3. Disconnectome mapping showed the additional role of disconnection of left frontal gyri and thalamus. By contrast, these analyses did not identify voxels specifically associated with lexico-phonological search processes.Third, meta-analytic fMRI data (based on 72 studies) strikingly matched all structures identified by the lesion approach.These results support our modeling of the functional architecture of verbal fluency based on two control processes (strategic search and attention) operating on semantic and lexico-phonologic output processes. Multivariate analysis supports the prominent role of the temporopolar area (BA 38) in semantic fluency and the F3 triangularis area (BA 45) in letter fluency. Finally, the lack of voxels specifically dedicated to strategic search processes could be due to a distributed organization of executive functions warranting further studies.

A person who has suffered the total loss of a sensory system has, indirectly, suffered a brain lesion. Semantic and phonologic verbal fluency are used for evaluation of executive function and language. The aim of this study is evaluation and comparison of phonemic and semantic verbal fluency in acquired blinds. We compare 137 blinds and 124 sighted people in verbal fluency task. The tasks were phonemic and semantic verbal fluency test that subjects should be generate as many word as possible in a limited amount of time for a given letter (Phonemic fluency) or a given category (Semantic fluency). Independent T Test was used to comparing blind with sighted. Findings show significant difference between two groups so that that sighted subjects have higher performance in semantic verbal fluency task (p = 0.000). Comparing sighted and blind subjects in phonemic verbal fluency task shows performance in sighted subjects (p = 0.000). Based on this study blinds have lower performance in semantic and phonemic verbal fluency task as a executive function of frontal lobe.

ABSTRACTVerbal fluency tasks, in which participants generate words during a set time, have been used in research and assessments of neurobiological disorders and impairments. Research on verbal fluency in dyslexia has shown impaired performance in semantic and letter fluency. However, studies report inconsistent results, and action fluency has not been examined in dyslexia. Current research has mainly examined verbal fluency in relation to executive functions, vocabulary, and phonological processing. The present study examined performance on letter, semantic, and action fluency in relation to reading ability in 42 students in higher education, of which 16 had developmental dyslexia and 26 had typical reading development. It was examined if verbal fluency can predict variance in reading ability when group, phonological awareness, and rapid automatized naming are controlled for. Results showed impaired verbal fluency in the developmental dyslexia group. Action fluency and group were significant predictors of reading ability, together explaining 73% of the variance, in a backward elimination regression analysis. The results point to a possible, unique connection between action fluency and reading ability; this connection is discussed based on their neurocognitive underpinnings.

Previous research has shown that word-finding difficulties in older age are associated with functional and structural brain changes. Functional brain networks, measured through electroencephalography, reflect the brain’s neurophysiological organisation. However, the utility of functional brain networks, to predict word-finding in older and younger adults has not yet been investigated. This study utilised eyes-closed resting-state electroencephalography data (61 channels) from the Leipzig Study for Mind-Body-Emotion Interactions dataset (Babayan et al., 2019) to investigate the relationship between functional brain networks and word-finding ability in 53 healthy right-handed younger (aged 20–35) and 53 (aged 59–77) older adults. Brain segregation reflects the efficiency of localised brain regions to process information, while brain integration reflects the efficiency of global information processing between distant brain regions. Word-finding ability was quantified as the number of orally produced words during a semantic and letter fluency task. Multiple linear regression revealed that, in older adults, greater synchronised brain activity was associated with lower semantic fluency. Irrespective of age, greater brain segregation was related to lower semantic fluency. Increased brain integration corresponded to greater semantic fluency in older adults. Both older and younger participants with a more optimised balance between brain segregation and integration performed better on semantic fluency. These findings suggest that word-finding ability seems to be related to brain segregation and integration, possibly indicating alterations in cognitive control or compensatory changes in brain activity. The article further provides a discussion on neural dedifferentiation, hyper-synchronisation, study limitations, and directions for future research.

Background: Among the factors that influence word retrieval are characteristics of the stimulus (e.g., length, frequency), characteristics of the individual (e.g., age, education), and characteristics of the task itself. Task factors have not been studied as thoroughly as stimulus and individual factors; in fact, it is often implicitly assumed that groups should be expected to perform similarly in any task involving lexical retrieval. Aims: This assumption was explicitly investigated in the current study by comparing word retrieval in healthy younger, middle-aged and older adults using three tasks with different stimulus and response characteristics. We hypothesised that the degree of constraint of the task would negatively affect word-retrieval performance in normally ageing participants. Methods & Procedures: Word retrieval was examined in three tasks: picture naming, vocabulary definition, and verbal fluency. The relationship of performance to age and education within each task, and the relationships of performance across tasks, were examined in order to clarify the nature of age-related word-retrieval decline. Outcomes & Results: Age-related declines in word retrieval were found in picture naming and verbal fluency tasks, whereas an age advantage was found for vocabulary definition. Conclusions: The task constraint hypothesis was partly supported. Unanticipated results require a revision of the hypothesis to take into account the nature of the constraints in each task, relative to the mechanisms underlying age-related declines in lexical retrieval.

Objective:Semantic verbal fluency (SVF) has traditionally been correlated with activity in the left anterior temporal lobe. Damage to the anterior temporal lobe, such as from a traumatic brain injury (TBI) or neurodegenerative disease, can result in impairments in semantic fluency and language expression. Although the orbitofrontal cortex (OFC) is not well studied as being correlated to this process, its functional connectivity to language-related brain regions, such as the inferior frontal gyrus (Broca’s area), suggests it may also play a role in SVF. In fact, preliminary research has shown that lesions in the OFC are associated with semantic fluency deficits (Almairac et al. 2015). As such, the goal of this study was to investigate whether OFC volume correlates with SVF in a population of Veterans with a prior TBI.Participants and Methods:Thirty-five Veterans who sustained TBIs were included in this study (11% female, age M = 41.77, SD = 11.27; years of education M =14.94, SD = 1.62). All participants underwent a magnetic resonance imaging (MRI) and regional normative volumes were standardized to account for differences in brain size (volume of brain area/total brain volume). Participants were given the Delis Kaplan Executive Function System (D-KEFS) verbal fluency subtest to measure verbal generativity. A Pearson correlation was conducted to investigate the relationship between OFC volume and SVF performance. Post hoc analysis was conducted with Veterans who met the criteria for a TBI sustained by a blast to the head (n = 25).Results:A significant positive correlation emerged between left OFC volume and semantic fluency (category subtest; p = .03, r = .35). Additional analyses with Veterans with blast-related TBIs indicated a significant correlation between the volume of the OFC and performance on the category (p = .02, r = .45), and switching (p = .02, r = .43) subtests of the D-KEFS verbal fluency test.Conclusions:These findings demonstrate a correlation between the volume of the left OFC and SVF performance. Specifically, Veterans with TBIs had decreased volume of the OFC which correlated with deficits on a SVF task. Among Veterans with blast-related TBIs, both category and category switching subtests correlated with OFC volume. Given the functional connectivity between the OFC and language areas of the brain, this study highlights the importance of analyzing associated cortical regions beyond the anterior temporal lobe when studying SVF performance.

Bipolar disorder (BD) is a chronic psychiatric condition characterized by episodes of mania, hypomania, and depression. Due to the cognitive impairments associated with BD, patients frequently experience difficulties in attention, memory, and executive functions, which in turn adversely affect specific aspects of their language abilities, such as word retrieval, verbal fluency, and the organization of coherent speech. The present study aims to determine the extent to which the verbal fluency skills of native Turkish-speaking individuals with BD are impaired compared to healthy controls and to identify whether there are differences in verbal fluency skills and their subcategories between bipolar I disorder (BD I) and bipolar II disorder (BD II) groups. A cross-sectional comparative design was employed in this study, including 39 euthymic patients diagnosed with BD I or BD II and 39 healthy controls. Verbal fluency was assessed using a standardized task comprising semantic fluency, semantic switching, phonemic fluency, and automatic speech subtests. All assessments were conducted under blinded conditions, and scoring was performed by independent raters. Group comparisons were carried out using ANOVA, Kruskal-Wallis, and ANCOVA analyses; age was controlled for through covariance analysis. Additionally, sensitivity analyses were conducted within the 25-55 age range. The control group demonstrated significantly higher performance than the BD groups across all semantic and phonemic verbal fluency tasks. No statistically significant differences were observed between the groups in automatic speech tasks. When comparing the BD I and BD II groups, a statistically significant difference was found only in the action (verb) category, with the BD II group outperforming the BD I group. The findings indicate that bipolar disorder is associated with marked impairments in semantic and phonemic verbal fluency, while automatic speech abilities appear to be relatively preserved. Moreover, the observed difference between BD subtypes-particularly in the action (verb) category-suggests that the type of the disorder may differentially influence cognitive-linguistic functioning.

Numerous variants of verbal fluency tasks exist within clinical and research domains that purport to measure “executive function.” However, to date, there has been a paucity of research examining what specific abilities are measured by these tasks. In this study, the relationships between a select group of cognitive constructs and phonemic, semantic, alternating, and excluded-letter verbal fluency tests were examined in 93 young healthy individuals (aged 18 to 35 years old). Forward-selection multiple regression analyses were performed for each fluency task. Phonemic fluency was associated with verbal intellectual function and processing speed; semantic fluency was associated with working memory and semantic word retrieval; excluded-letter fluency was associated with processing speed; and alternating fluency was associated with semantic word retrieval. These results highlight verbal intellectual function, processing speed, and semantic word-retrieval contributions to verbal fluency performances. The main conclusion from this study is that the abilities associated with verbal fluency performance in a young healthy population are multifactorial and differ across fluency variants. These findings progress our theoretical understanding of what is measured by different verbal fluency tasks and will assist interpretation of performance.

Objective: The aim of this study is to contrast the genetics of neuropsychological tasks in individuals from nuclear families clustering ADHD in a Caribbean community. Method: We recruited and clinically characterized 408 individuals using an extensive battery of neuropsychological tasks. The genetic variance underpinning these tasks was estimated by heritability. A predictive framework for ADHD diagnosis was derived using these tasks. Results: We found that individuals with ADHD differed from controls in tasks of mental control, visuospatial ability, visuoverbal memory, phonological and verbal fluency, verbal and semantic fluency, cognitive flexibility, and cognitive ability. Among them, tasks of mental control, visuoverbal memory, phonological fluency, semantic verbal fluency, and intelligence had a significant heritability. A predictive model of ADHD diagnosis using these endophenotypes yields remarkable classification rate, sensitivity, specificity, and precision values (above 80%). Conclusion: We have dissected new cognitive endophenotypes in ADHD that can be suitable to assess the neurobiological and genetic basis of ADHD.

OBJECTIVETo test the hypothesis that semantic impairment is present in both patients with dementia with Lewy bodies (DLB) and those with dementia of Alzheimer's type (DAT).METHODSA comprehensive battery of neuropsychological...

Verbal fluency performance in amnestic MCI and older adults with cognitive complaints