Fluency Performance Research Articles

Depressive Symptoms are Associated with Decline Over Time in Verbal Fluency Performance in Female but Not Male Community-Dwelling Older Adults

ABSTRACT Objective The current study was designed to examine associations between depressive symptoms and longitudinal declines in category and letter fluency performance in a gender-stratified sample of older adults. Method Participants were community-residing older adults (females: n = 289; males: n = 233) followed annually (2011–2018) as part of a cohort study conducted at Albert Einstein College of Medicine in New York. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS). Standard forms assessed category and letter fluency performance. Participants were dementia-free during study enrollment. Results The presence of baseline depressive symptoms suggestive of subclinical depression was associated with a worse longitudinal decline in category fluency performance in female but not male participants. These associations remained significant when excluding participants with prevalent and incident mild cognitive impairment and incident dementia. Irrespective of gender, letter fluency performance did not decline over time and was not influenced by the presence of depressive symptoms. Discussion The present study’s results can aid in identification of older adults who may be at greater risk for cognitive decline, and add to the limited literature examining the influence of gender on longitudinal associations between depressive symptoms and verbal fluency performance.

The Role of Early Literacy Skills in Beginning to Read in Turkish: Longitudinal Findings from First Graders

The aim of this longitudinal study is to investigate the effects of early literacy skills on beginning to read in a transparent orthography, viz. Turkish. In line with this aim, a total of eighty-four participants were followed from preschool to the end of the first grade and the extent to which participants' early literacy skills in the preschool period predict their future reading performances was examined. All the data gathered in the study were collected individually at one-year intervals. The participants’ early literacy skills were tested by the "Test of Early Literacy (TEL)", reading comprehension skills was obtained with a text containing 162 words and 10 multiple choice questions, reading fluency performances were calculated with the formula of correct number of words per minute. Data were computed through correlation analysis, and hierarchical regression analysis. Results suggest that regarding phonological awareness, early literacy sub-skills, especially those contributing to or serving oral comprehension had positive effects on reading fluency and reading comprehension at the end of the first grade. Valuable conclusions have been drawn from this finding about the role of phonological awareness, and its contribution to reading in an agglutinative orthography such as Turkish. Obtained results are discussed in relation to the literature.

Diversity in verbal fluency performance and its associations with MRI-informed brain age matrices in normal ageing and neurocognitive disorders.

Category verbal fluency test (CVFT) has been widely used to assess and monitor the cognitive capacities in epidemiological studies and clinical trials. Pronounced discrepancy in CVFT performance has been found in individuals with different cognitive statuses. This study aimed to combine the psychometric and morphometric approaches to decode the complex verbal fluency performance in senior adults with normal ageing and neurocognitive disorders. This study adopted a two-stage cross-sectional design involving quantitative analyses of neuropsychological and neuroimaging data. In study I, capacity- and speed-based measures of CVFT were developed to evaluate the verbal fluency performance in normal ageing seniors (n=261), those with mild cognitive impairment (n=204), and those with dementia (n=23) whose age range is from 65 to 85 years. In study II, structural magnetic resonance imaging-informed gray matter volume (GMV) and brain age matrices were calculated in a subsample (n=52) from Study I through surface-based morphometry analysis. With age and gender as covariates, Pearson's correlation analysis was used to examine the associations of CVFT measures, GMV, and brain age matrices. Speed-based measures showed extensive and stronger associations with other cognitive functions than capacity-based measures. The component-specific CVFT measures showed shared and unique neural underpinnings with lateralized morphometric features. Moreover, the increased CVFT capacity was significantly correlated with younger brain age in mild neurocognitive disorder (NCD) patients. We found that the diversity of verbal fluency performance in normal ageing and NCD patients could be explained by a combination of memory, language, and executive abilities. The component-specific measures and related lateralized morphometric correlates also highlight the underlying theoretical meaning of verbal fluency performance and its clinical utility in detecting and tracing the cognitive trajectory in individuals with accelerated ageing.

Gray matter volume and within-task verbal fluency performance among older adults

The current study examined the relationship between gray matter volume (GMV) and rate of word generation over the course of three consecutive 20-sec intervals in 60-sec letter and category verbal fluency (VF) tasks. Attenuated rate of within-person word generation in VF provides incremental information beyond total scores and predicts increased risk of incident Mild Cognitive Impairment (MCI). No studies to date, however, have determined the structural neural substrates underlying word generation rate in VF. Participants were 70 community-residing adults ≥ 65 years, who completed the letter and category VF tasks and a 3 T structural MRI scan. Linear mixed effects models (LMEMs) were used to determine the moderating effect of GMV on word generation rate. Whole brain voxel-wise LMEMs, adjusted for age, gender, education, Wide-Range Achievement Test – reading subtest score (WRAT3), and global health score, were run using permutation methods to correct for multiple comparisons. Lower GMV, primarily in frontal regions (superior frontal, rostral middle frontal, frontal pole, medial orbitofrontal, and pars orbitalis), were related to attenuated word generation rate, especially for letter VF. We propose that lower frontal GMV underlies inefficient executive word search processes reflected by attenuated word generation slope in letter VF amongst older adults.

What Drives Animal Fluency Performance in Cantonese-Speaking Chinese Patients with Adult-Onset Psychosis?

Among the numerous studies investigating semantic factors associated with functioning in psychotic patients, most have been conducted on western populations. By contrast, the current cross-sectional study involved native Cantonese-speaking Chinese participants. Using the category fluency task, we compared performance between patients and healthy participants and examined clinical and sociodemographic correlates. First-episode psychosis patients (n = 356) and gender- and age-matched healthy participants (n = 35) were asked to generate as many 'animals' as they could in a minute. As expected, patients generated fewer correct responses (an average of 15.5 vs. 22.9 words), generated fewer clusters (an average of 3.7 vs. 5.4 thematically grouped nouns), switched less between clusters (on average 8.0 vs. 11.9 switches) and, interestingly, produced a larger percentage of Chinese zodiac animals than healthy participants (an average of 37.7 vs. 24.2). However, these significant group differences in the clusters and switches disappeared when the overall word production was controlled for. Within patients, education was the strongest predictor of category fluency performance (namely the number of correct responses, clusters, and switches). The findings suggest that an overall slowness in patients may account for the group differences in category fluency performance rather than any specific abnormality per se.

Verbal fluency tests assess global cognitive status but have limited diagnostic differentiation: evidence from a large-scale examination of six neurodegenerative diseases.

Verbal fluency is widely used as a clinical test, but its utility in differentiating between neurodegenerative dementias and progressive aphasias, and from healthy controls, remains unclear. We assessed whether various measures of fluency performance could differentiate between Alzheimer's disease, behavioural variant of frontotemporal dementia, non-fluent and semantic variants of primary progressive aphasia, progressive supranuclear palsy, corticobasal syndrome and healthy controls. Category and letter fluency tasks were administered to 33 controls and 139 patients at their baseline clinical visit. We assessed group differences for total number of words produced, psycholinguistic word properties and associations between production order and exemplar psycholinguistic properties. Receiver operating characteristic curves determined which measure could best discriminate patient groups and controls. The total word count distinguished controls from all patient groups, but neither this measure nor the word properties differentiated the patient groups. Receiver operating characteristic curves revealed that, when comparing controls to patients, the strongest discriminators were total word count followed by word frequency. Word frequency was the strongest discriminator for semantic variant of primary progressive aphasia versus other groups. Fluency word counts were associated with global severity as measured by Addenbrooke's Cognitive Examination Revised. Verbal fluency is an efficient test for assessing global brain-cognitive health but has limited utility in differentiating between cognitively and anatomically disparate patient groups. This outcome is consistent with the fact that verbal fluency requires many different aspects of higher cognition and language.

Regional white matter and gray matter damage and cognitive performances in multiple sclerosis according to sex.

In this study, we investigated whether regional distribution of white matter (WM) lesions, normal-appearing [NA] WM microstructural abnormalities and gray matter (GM) atrophy may differently contribute to cognitive performance in multiple sclerosis (MS) patients according to sex. Using the same scanner, brain 3.0T MRI was acquired for 287 MS patients (females = 173; mean age = 42.1 [standard deviation, SD = 12.7] years; relapsing-remitting = 196, progressive = 91; median Expanded Disability Status Scale = 2.5 [interquartile range, IQR = 1.5-5.0]; median disease duration = 12.1 [IQR = 6.3-19.0] years; treatment: none = 70, first-line = 130, second-line = 87) and 172 healthy controls (HC) (females = 92; mean age = 39.3 [SD = 14.8] years). MS patients underwent also Rao's neuropsychological battery. Using voxel-wise analyses, we investigated in patients sex-related differences in the association of cognitive performances with WM lesions, NAWM fractional anisotropy (FA) and GM volumes (p < 0.01, family-wise error [FWE]). Sixty-six female (38%) and 48 male (42%) MS patients were cognitively impaired, with no significant between-group difference (p = 0.704). However, verbal memory performance was worse in males (p = 0.001), whereas verbal fluency performance was worse in females (p = 0.004). In both sexes, a higher T2-hyperintense lesion prevalence in cognitively-relevant WM tracts was significantly associated with worse cognitive performance (p ≤ 0.006), with stronger associations in females than males in global cognition (p ≤ 0.004). Compared to sex-matched HC, male and female MS patients had widespread lower NAWM FA and GM volume (p < 0.01). In both sexes, worse cognitive performance was associated with widespread reduced NAWM FA (p < 0.01), with stronger associations in females than males in global cognition and verbal memory (p ≤ 0.009). Worse cognitive performance was significantly associated with clusters of cortical GM atrophy in males (p ≤ 0.007) and mainly with deep GM atrophy in females (p ≤ 0.006). In this study, only limited differences in cognitive performances were found between male and female MS patients. A disconnection syndrome due to focal WM lesions and diffuse NAWM microstructural abnormalities seems to be more relevant in female MS patients to explain cognitive impairment.

Phonological Verbal Fluency Test for Russian-Speaking Children

Introduction: Verbal fluency tasks are mainly used for assessment of verbal fluency and have proven useful for differential diagnosis. The first objective of the study was to provide normative data on phonemic verbal fluency (for letters “Π” [p], “O” [o], “C” [s]) in children population. The second objective of the study was to establish diagnostic validity of the present task and to collect normative data on participants who survived posterior fossa tumor (PFT) and participants with treated hemoblastosis. Method: For diagnostics, we used verbal fluency test. The normative sample consisted of 746 participants aged 7–16 years. A linear multiple regression analysis was implemented for each dependent variable with age, gender, disease for all participants and academic achievement as predictors in normative sample. The performance of 746 healthy participants was compared to the performance of 118 participants who survived PFT and 492 participants who survived hemoblastosis using one-way ANOVA analysis. Results: Healthy children have better verbal fluency than their peers who survived cancer. In the group of healthy children, we assessed the relationship between verbal fluency and school performance. A significant correlation with the “Russian language” subject (r = 0.127; p < 0.001) emerged. In all three groups of children, age and gender turned out to be significant factors that affected the characteristics of verbal fluency. Conclusion: Our data will contribute to increasing the accuracy of verbal fluency deficit detection in Russian speakers and will be useful for differential diagnosis of cognitive impairment for children who have survived oncological diseases of various geneses.

Investigating the relation between L2 pauses, syntactic complexity, and pause location: Longitudinal data from L2-Spanish study-abroad learners

Inverse relations, or ‘trade-off effects’, are a common outcome of interlanguage development: a learner may increase performance in one linguistic domain while simultaneously decreasing performance in another. In this study, we investigate the relationships between one aspect of fluency (pause usage) and two aspects of syntactic complexity (utterance length and subordination) in relation to the location of pauses (between-clause or within-clause) in second-language (L2) oral narratives. The longitudinal analysis is based on monologic data produced by 16 English-speaking L2 learners of Spanish who participated in a seven-week study-abroad program in Spain. Overall, the learners decreased their silent-pause rate over the course of the program while concurrently increasing their number of syntactically complex clauses. Notably, the data suggest a systematic trade-off between pausing and complexity: the learners consistently produced more pauses (i.e. decreased fluency performance) during the elocution of the most complex clauses involving clausal subordination (i.e. increased complexity performance) in comparison to utterances lacking such subordination. We contextualize the findings within models of oral production and discuss how this research generates new insight into the processing factors that modulate pause usage in L2 speech.

Effect of Sleep Duration on Working Memory and Verbal Fluency Functions of Medical Faculty Students

Effect of Sleep Duration on Working Memory and Verbal Fluency Functions of Medical Faculty Students

The impact of hemodiafiltration on cognitive function in patients with end-stage renal disease.

Patients with end-stage renal disease are more likely to suffer cognitive impairment. Cognitive impairment may lead to long-term severe adverse consequences. To explore the impact of different blood purification therapy on cerebral blood flow and cognitive functions in end-stage renal disease. This prospective study evaluated patients with end-stage renal disease undergoing blood purification from January to March 2021. Matched healthy controls were also included. Participants performed neurocognitive measurements, including a mini-mental state examination, logical memory test-20-minutes delayed, verbal fluency test, digit span test, clock drawing test, and stroop color and word test C. In addition, we tested plasma amyloid-β protein levels, serum Fe and hemoglobin levels in blood samples. Cerebral blood flow was measured using pulsed pseudocontinuous arterial spin labeling. We analyzed and compared the correlation between cognitive function, biomarkers, and cerebral blood flow between patients and healthy subjects, as well as between patients with different treatments. A total of 44 patients with end-stage renal disease (mean age, 57.39 years ± 8.63) and 46 healthy controls (mean age, 56.15 years ± 6.40) were recruited. Patients receive hemodialysis three times a week, and 27 of them have been replaced hemodialysis for hemodiafiltration twice a month. The cognitive function of patients was worse than healthy controls (P < 0.05). The patients showed higher plasma concentrations of amyloid-β40, amyloid-β42, Tau, and pTau181 than healthy controls (P < 0.05). The group receiving both hemodialysis and hemodiafiltration had higher cerebral blood flow signal values in the left caudate nucleus (chuster-level P < 0.05, voxel-level P < 0.001). They also exhibited better verbal fluency function than the hemodialysis-only group (P < 0.05). Patients with the end-stage renal disease showed widespread cognitive declines. Cerebral blood flow generally decreased in the cerebral cortex and increased in subcortical regions. The hemodiafiltration may protect verbal function by increasing cerebral blood flow in the left caudate.

Longitudinal decline in semantic versus letter fluency, but not their ratio, marks incident Alzheimer's disease in Latinx Spanish-speaking older individuals.

To compare longitudinal verbal fluency performance among Latinx Spanish speakers who develop Alzheimer's disease to those who do not develop dementia in absolute number of words produced on each task and their ratio to combine both scores. Participants included 833 Latinx Spanish-speaking older adults from a community-based prospective cohort in Manhattan. We performed growth curve modeling to investigate the trajectories of letter and semantic fluency, and their ratio (i.e., 'semantic index'), between individuals who developed Alzheimer's disease and those who did not (i.e., controls). The semantic index quantifies the proportion of words generated for semantic fluency in relation to the total verbal fluency performance. Letter fluency performance did not decline in controls; we observed a linear decline in those who developed Alzheimer's disease. Semantic fluency declined in both groups and showed an increased rate of change over time in the incident Alzheimer's disease group; in comparison, the control group had a linear and slower decline. There were no group differences in the longitudinal trajectory (intercept and slope) of the semantic index. A decline in letter fluency and a more rapid and accelerating decline over time in semantic fluency distinguished people who developed Alzheimer's disease from controls. Using the semantic index was not a superior marker of incident Alzheimer's disease compared to examining the two fluency scores individually. Results suggest the differential decline in verbal fluency tasks, when evaluated appropriately, may be useful for early identification of Alzheimer's disease in Latinx Spanish speakers, a historically understudied population.

Different Sources of Sugar Consumption and Cognitive Performance in Older Adults: Data From the National Health and Nutrition Examination Survey 2011-2014.

Excess sugar consumption, particularly in sugar-sweetened beverages (SSBs), has been linked to poor cognitive performance. We aimed to assess the association of consumption of total sugar, as well as the consumption of SSBs, solid desserts, and 100% fruit juice with cognitive performance among older adults. Consumption of total sugar, SSBs, solid desserts, and 100% fruit juice were obtained from the 24-hr recall interview. Cognitive performance was evaluated using the Consortium to Establish a Registry for Alzheimer's Disease word list, the Animal Fluency Test, and the Digit Symbol Substitution Test. Binary logistic regression models were used to evaluate the association between consumption of sugar (total and from different sources) and cognitive performance. A total of 1,938 participants aged 60years or older from the National Health and Nutrition Examination Survey 2011-2014 were included. Compared to the lowest tertile, the highest tertile of total sugar consumption was independently associated with higher odds of low memory performance (odds ratio [OR]=1.87, 95% confidence interval [CI]=1.00; 3.50, p=.049). Consumption of SSBs was associated with higher risk of low memory (OR=1.58, 95% CI=1.11; 2.25, p=.014), whereas consumption of solid desserts was associated with lower risk of low verbal fluency performance (OR=0.62, 95% CI=0.41; 0.95, p=.032). Higher consumption of total sugars and SSBs was associated with lower memory performance, while consumption of solid desserts was associated with higher verbal fluency performance.

Does comorbid depression impact executive functioning (EF) in adults diagnosed with ADHD?: a comparison of EF across diagnoses in clinically-referred individuals

ABSTRACT Introduction Executive functioning (EF) is a salient factor in both ADHD as well as depressive disorders. However, sparse literature has examined whether depression severity impacts EF concurrently among adults with ADHD. The goal of this study was to examine differences in EF between adult patients diagnosed with ADHD and those diagnosed with a non-ADHD primary psychopathological condition, as a function of both ADHD presentation and depression severity in a diverse clinical sample. Method This crosssectional study included 404 adult patients clinically referred for neuropsychological evaluation to assist with differential diagnosis and/or treatment planning related to known or suspected ADHD. Various EF tasks and a measure of depression severity were administered. One-way MANOVA analyses were conducted to compare EF performance between individuals diagnosed with ADHD or a non-ADHD primary psychopathological condition, with additional analyses examining group differences based on ADHD presentation and depression severity. Regression analyses also examined the potential contribution of depression severity to each EF measure within each group. Results No significant EF performance differences were found when comparing individuals diagnosed with ADHD and those with a non-ADHD primary psychopathological condition, nor based on ADHD presentation. When comparing across groups using cut-offs for high or low depression, only one EF measure showed significant differences between groups. Further, depression severity generally did not predict reduced EF performances with the exception of verbal fluency and working memory performances in select groups. Conclusions This study demonstrated that individuals with ADHD generally perform comparably on EF measures regardless of the presence or absence of comorbid depression. These results suggest further examination of EF deficits when they emerge for adults with ADHD, especially beyond comorbid depression severity.

Sequential production of motor-action verb subtypes in Parkinson's disease patients.

The aim of this study was to characterize the sequential production of three subtypes of MAVs in PD patients: whole body (e.g., run), specific body part (e.g., kick), and instrumental (e.g., saw). This study also aimed to identify the production characteristics for each of the two main phases in fluency performance: selection (initial abundant item production) and retrieval (more paced and scarce production). This study involved a group of 20 nondemented, on-medication PD patients, with an average age of 66.59 years (standard deviation = 4.13), and a comparison group (CG) of 20 normal elderly individuals, matched by years of education and controlled for cognitive performance and depression. Both groups performed a classical verb fluency task. Sequential word-by-word analyses were conducted. Significant differences were found at the initial production of whole-body MAVs and the overall production of instrumental verbs (both measures were lower in the PD group). A repeated-measures analysis of variance confirmed the linear CG performance and the quadratic PD performance. PD patients present altered production of whole-body and instrumental MAVs. This proposal for the semantic sequential analysis of motor verbs deserves further investigation, as a new methodology for the evaluation of fluency performance in motor-related disease.

Clustering and switching analysis of verb fluency in individuals with Alzheimer’s disease

To investigate verb fluency performance in individuals with Alzheimer's disease compared with healthy older adults by analyzing total correct responses, number of clusters, average cluster size, and number of switches. This is a case-control study of 39 healthy older adults and 29 older adults with a diagnosis of Alzheimer's disease. Verb fluency performance was analyzed in terms of total number of correct verbs retrieved, number of clusters, average cluster size, and number of switches. To obtain the study outcomes, we previously conducted a procedure for categorization of the verbs that would compose the clusters. The classification of verbs was adapted for this study, including assessment by raters and analysis of inter-rater reliability. Individuals with Alzheimer's disease showed significantly poorer performance than healthy controls in the number of switches and total number of correct verbs retrieved. The two groups did not differ significantly in the other measures. In this study, individuals with Alzheimer's disease showed impaired verb fluency, characterized by a reduced number of verbs retrieved and fewer transitions between verb categories. The findings suggest that, in Alzheimer's disease, verb fluency is more sensitive to cognitive deficits resulting from executive dysfunction than from semantic disruption.

Neural correlates of verbal fluency revealed by longitudinal T1, T2 and FLAIR imaging in stroke

Diffusion-weighted imaging has been widely used in the research on post-stroke verbal fluency but acquiring diffusion data is not always clinically feasible. Achieving comparable reliability for detecting brain variables associated with verbal fluency impairments, based on more readily available anatomical, non-diffusion images (T1, T2 and FLAIR), enables clinical practitioners to have complementary neurophysiological information at hand to facilitate diagnosis and treatment of language impairment. Meanwhile, although the predominant focus in the stroke recovery literature has been on cortical contributions to verbal fluency, it remains unclear how subcortical regions and white matter disconnection are related to verbal fluency. Our study thus utilized anatomical scans of ischaemic stroke survivors (n = 121) to identify longitudinal relationships between subcortical volume, white matter tract disconnection, and verbal fluency performance at 3- and 12-months post-stroke. Subcortical grey matter volume was derived from FreeSurfer. We used an indirect probabilistic approach to quantify white matter disconnection in terms of disconnection severity, the proportion of lesioned voxel volume to the total volume of a tract, and disconnection probability, the probability of the overlap between the stroke lesion and a tract. These disconnection variables of each subject were identified based on the disconnectome map of the BCBToolkit. Using a linear mixed multiple regression method with 5-fold cross-validations, we correlated the semantic and phonemic fluency scores with longitudinal measurements of subcortical grey matter volume and 22 bilateral white matter tracts, while controlling for demographic variables (age, sex, handedness and education), total brain volume, lesion volume, and cortical thickness. The results showed that the right subcortical grey matter volume was positively correlated with phonemic fluency averaged over 3 months and 12 months. The finding generalized well on the test data. The disconnection probability of left superior longitudinal fasciculus II and left posterior arcuate fasciculus was negatively associated with semantic fluency only on the training data, but the result aligned with our previous study using diffusion scans in the same clinical population. In sum, our results presented evidence that routinely acquired anatomical scans can serve as a reliable source for deriving neural variables of post-stroke verbal fluency performance. The use of this method might provide an ecologically valid and more readily implementable analysis tool.

Análise de clustering e switching da fluência de verbos em indivíduos com doença de Alzheimer

ABSTRACT Purpose To investigate verb fluency performance in individuals with Alzheimer’s disease compared with healthy older adults by analyzing total correct responses, number of clusters, average cluster size, and number of switches. Methods This is a case-control study of 39 healthy older adults and 29 older adults with a diagnosis of Alzheimer’s disease. Verb fluency performance was analyzed in terms of total number of correct verbs retrieved, number of clusters, average cluster size, and number of switches. To obtain the study outcomes, we previously conducted a procedure for categorization of the verbs that would compose the clusters. The classification of verbs was adapted for this study, including assessment by raters and analysis of inter-rater reliability. Results Individuals with Alzheimer’s disease showed significantly poorer performance than healthy controls in the number of switches and total number of correct verbs retrieved. The two groups did not differ significantly in the other measures. Conclusion In this study, individuals with Alzheimer’s disease showed impaired verb fluency, characterized by a reduced number of verbs retrieved and fewer transitions between verb categories. The findings suggest that, in Alzheimer’s disease, verb fluency is more sensitive to cognitive deficits resulting from executive dysfunction than from semantic disruption.

Language Fluency Deficits in Post-treatment Lyme Disease Syndrome.

Recent neurocognitive studies of patients with post-treatment Lyme disease syndrome (PTLDS) find consistent deficits in memory and processing speed. Language fluency deficits are observed as well but may be secondary to poor memory and slowing rather than an independent deficit. This study performed a secondary analysis of data presented previously, including individuals with PTLDS and comparison samples of healthy volunteers (HC) and patients with major depressive disorder (MDD), to determine if language fluency deficits could be accounted for by poor performance in these other neurocognitive domains. Basic verbal abilities, memory, and processing speed were all significantly associated with fluency performance. MDD patients' fluency deficits relative to HC were accounted for by these covariates. However, PTLDS patients' poorer fluency performance relative to both other groups was not. Language fluency appears to be an independent area of neurocognitive deficit within the constellation of PTLDS symptoms.

SLEEP DURATION MEDIATES THE RELATIONSHIP BETWEEN LETTER FLUENCY AND COGNITION

Abstract Changes in cognition are a normative part of aging. Verbal fluency is widely used for assessing cognitive function, including predicting mild cognitive impairment. As people age, sleep duration and quality decrease. This has been associated with cognitive decline; individuals with low-quality sleep (fewer hours and difficulties with initiation or maintenance of sleep) are more likely to complain of poorer cognition. Lack of sleep is detrimental to verbal fluency (word production). Longer sleep has been linked to memory deficits and is a potential indicator of mild cognitive impairment. This study aimed to address the relationship between verbal fluency and cognitive function as mediated by sleep duration. Participants included 31 middle-aged adults (female, n=19;age=53.55±7.18yrs) and 24 older adults (female=14; age=70.33±3.69yrs). The MoCA assessed cognitive functioning. Verbal fluency (90 seconds each) was measured via category word (animals; semantic verbal fluency) and letter word (phonemic verbal fluency; F,A,S). Mediation models used Baron and Kenny’s (1986) approach for estimating mediation effects, controlling for age and education. Category results were non-significant. However, sleep duration partially mediated the relationship between letter fluency for each letter and cognitive function, respectively (F:F(2,52)=7.31, p=.002, R2=.22; A: F(2,52)=3.80, p=.029, R2=.18; S: F(2,52)=5.47, p=.007, R2=.17). Sleep hours were negatively associated with letter fluency, meaning fewer hours of sleep improved fluency performance, which in turn was positively associated with MOCA scores (F: b=-.378, 95%CI [-0.64, 0.02]; A: b=-.172, 95%CI [-0.42, 0.01]; S: b=-.24, 95%CI [-0.64, 0.02]. This coincides with the abovementioned literature and helps further understand how sleep and cognitive performance are related.