Serial Recall Order of Category Fluency Words: Exploring Its Neural Underpinnings

Background: Although performance on the category fluency test (CFT) is influenced by many cognitive functions (i.e., including language, executive functioning and speed of processing), item-level scoring methods of CFT performance might be a promising way to capture aspects of semantic memory that are less influenced by intervenient abilities. One such approach is based on the calculation of correlation coefficients that quantify the association between item-level features and the serial order with which words are recalled (SRO).Methods: We explored the neural underpinnings of 10 of these correlational indices in a sample of 40 healthy adults who completed a classic 1-min CFT and an MRI protocol inclusive of T1-weighted (analysed with voxel-based morphometry) and resting-state fMRI sequences for the evaluation of the default-mode network (DMN). Two sets of linear models were defined to test the association between neural maps and each correlational index: a first set in which major demographic and clinical descriptors were controlled for and a second set in which, additionally, all other 9 correlational indices were regressed out.Results: In the analysis of the DMN, ‘SRO-frequency’, ‘SRO-dominance’ and ‘SRO-body-object interaction’ correlational indices were all negatively associated with the anterior portion of the right temporoparietal junction. The ‘SRO-frequency’ correlational index was also negatively associated with the right dorsal anterior cingulate and the ‘SRO-dominance’ correlational index with the right lateral prefrontal cortex. From the second set of models, the ‘SRO-typicality’ correlational index was positively associated with the left entorhinal cortex. No association was found in relation to grey matter maps.Conclusion: The ability to retrieve more difficult words during CFT performance as measured by the correlational indices between SRO and item-level descriptors is associated with DMN expression in regions deputed to attentional reorienting and processing of salience of infrequent stimuli and dominance status. Of all item-level features, typicality appears to be that most closely linked with entorhinal functioning and may thus play a relevant role in assessing its value in testing procedures for early detection of subtle cognitive difficulties in people with suspected Alzheimer’s degeneration. Although exploratory, these findings warrant further investigations in larger cohorts.

Egg Consumption and 4-Year Change in Cognitive Function: The Rancho Bernardo Study

The role of dietary cholesterol in cognitive decline is unclear. Eggs are a rich source of nutrients and dietary cholesterol. This study examines the association of egg consumption with 4-year change in cognitive function in 890 older, community-dwelling adults. Participants were 357 men and 533 women aged □55y (means=70.1□8.4 and 71.5□8.8, respectively, p=0.016), from the Rancho Bernardo Cohort who attended a 1988-91 clinic visit. Egg intake was obtained with a food frequency questionnaire. Cognitive function was assessed with the Mini-Mental Status Exam (MMSE), Trails B and category fluency, and reassessed in 1992-96. In this sample, rates of egg consumption ranged from never (14.0% of men, 16.5% of women) to □5/week (7.0% of men, 3.8% of women; p=0.0013). Mean 1988-91 cognitive function scores for men vs. women were 27.5 vs. 27.7 on the MMSE (p=0.08), 105.9 vs. 121.6 on Trails B (p<0.0001), and 20.2 vs. 18.2 on category fluency (p<0.0001). Sex-specific regression analyses examined associations of egg consumption with change in cognitive function. In women, after adjustment for age and education, egg intake was associated with less decline over time in category fluency (beta=-.10, p=0.01), which remained significant after adjustment for smoking, alcohol, exercise, cholesterol, calorie intake, and protein intake (p=0.02). No other associations were found in women, and no associations were observed in men before and after adjustment for covariates. Results suggest that while high in dietary cholesterol, egg consumption is not associated with decline in cognitive function. For women, there may be a small beneficial effect for verbal memory.

Intensity of Walking Training Impacts Cognition Among Assisted Living Residents With Frailty

Exercise has many proven cognitive benefits but the precise intensity to modify cognition is unclear. This pilot study investigated the role of exercise intensity on cognitive outcomes among assisted living residents. We enrolled n=33 frail or pre-frail residents who completed an 8 week, twice-weekly walking intervention. Participants were 66% female, and on average were 88 years old with a MMSE score=25.6, and low cognitive scores (Category Fluency Animals=10.45, Category Fluency Vegetables=7.67, Trail Making Test A=60.82 seconds, Trail Making Test B=155.18 seconds). Walking sessions used 5-minute intervals focused on maximizing steps, fast speeds, and multi-directions for 45 minutes per session. Participants in the high intensity group walked at >70% heart rate maximum or RPE 15-17 and those randomized to the casual intensity group walked at <60% heart rate maximum or RPE <13. Results showed the casual-intensity group improved more on Category Fluency tests (increase of 0.88 animals and 1.06 vegetables) compared to the high-intensity group (increase of 0.12 animals and increase of 0.35 vegetables). On Trail Making Test A, high-intensity participants had a 7.47 second decrease in time to complete compared to the casual-intensity group (2.00 seconds increase). On Trail Making Test B, high-intensity participants decreased time to complete by 27.13 seconds compared to a 26.19 decrease in the casual-intensity group. Results show promising trends in the role of exercise intensity in impacting different elements of cognition among assisted living residents.

The Contribution of Bilingualism to Cognitive Functioning and Regional Brain Volume in Normal and Abnormal Aging

We examined the association between bilingualism, executive function (EF), and brain volume in older monolinguals and bilinguals who spoke English, Spanish, or both, and were cognitively normal (CN) or diagnosed with Mild Cognitive Impairment (MCI) or dementia. Gray matter volume (GMV) was higher in language and EF brain regions among bilinguals, but no differences were found in memory regions. Neuropsychological performance did not vary across language groups over time; however, bilinguals exhibited reduced Stroop interference and lower scores on Digit Span Backwards and category fluency. Higher scores on Digit Span Backwards were associated with a younger age of English acquisition, and a greater degree of balanced bilingualism was associated with lower scores in category fluency. The initial age of cognitive decline did not differ between language groups. The influence of bilingualism appears to be reflected in increased GMV in language and EF regions, and to a lesser degree, in EF.

Serial Recall Order and Semantic Features of Category Fluency Words to Study Semantic Memory in Normal Ageing

Background: Category Fluency Test (CFT) is a common measure of semantic memory (SM). Test performance, however, is also influenced by other cognitive functions. We here propose a scoring procedure that quantifies the correlation between the serial recall order (SRO) of words retrieved during the CFT and a number of linguistic features, to obtain purer SM measures. To put this methodology to the test, we addressed a proof-of-concept hypothesis whereby, in alignment with the literature, older adults would show better SM.Methods: Ninety participants (45 aged 18–21 years; 45 aged 70–81 years) with normal neurological and cognitive functioning completed a 1-min CFT. SRO was scored as an ordinal variable incrementing by one unit for each valid entry. Each word was also scored for 16 additional linguistic features. Participant-specific normalised correlation coefficients were calculated between SRO and each feature and were analysed with group comparisons and graph theory.Results: Younger adults showed more negative correlations between SRO and “valence” (a feature of words pleasantness). This was driven by the first five words generated. When analysed with graph theory, SRO had significantly higher degree and lower betweenness centrality among older adults.Conclusion: In older adults, SM relies significantly less on pleasantness of entries typically retrieved without semantic control. Moreover, graph-theory metrics indicated better optimised links between SRO and linguistic features in this group. These findings are aligned with the principle whereby SM processes tend to solidify with ageing. Although additional work is needed in support of an SRO-based item-level scoring procedure of CFT performance, these initial findings suggest that this methodology could be of help in characterising SM in a purer form.

Characteristics of Performance according to Type of Semantic Lexical Task in Normal Elderly and Individuals with Subjective Memory Impairment

Purpose: For comparison of a semantic knowledge processing of the elderly, particularly the normal individuals and individuals with subjective memory impairment, this study aims to clarify what factors of semantic knowledge task could sensitively discriminate between the two groups by conducting various types of tasks and analyzing the aspects.Methods: High/low frequency category fluency test, concrete/abstract noun word defining test, and semantic association task were performed by 30 normal subjects and 30 subjective memory impaired subjects over 65 years old. Total and each subcategory scores were assessed for the category fluency test and word defining test, and correct response and reaction time were measured for the semantic association task.Results: It was found that there were significant differences between the two groups in the total score of the category fluency task (p < 0.001), low-frequency category score, abstract noun word defining task score (p < 0.05), and reaction time of semantic association task (p < 0.01).Conclusion: The result showed that in case of a target word with lower contact frequency and more abstract concept, the elderly with subjective memory impairment have difficulties in neural-networking activation of semantic knowledge and control of interruption stimulation when approaching a target word, with increased reaction time. This findings demonstrate that a semantic and lexical task has a clinical significance in discriminating a subjective memory impairment group.

Continued methodological imprecisions, nontransparency, and misinterpretation in a meta-analysis of semantic fluency in schizophrenia: a comment on “Corrigendum to: Semantic memory impairment across the schizophrenia continuum: a meta-analysis of category fluency performance” by Tan et al.

Even after issuing a corrigendum, Tan et al.’s [2020 (Schizophr Bull Open 1(1), sgaa054)] clustering meta-analysis contains serious methodological imprecisions, it remains methodologically nontransparent, and the interpretations are not backed by the conventional ontology of semantic fluency.

Association between anemia, physical performance and cognitive function in Iranian elderly people: evidence from Bushehr Elderly Health (BEH) program

Background and objectives The present study aimed to investigate the relation between anemia and hemoglobin (Hgb) concentration, physical performance, and cognitive function in a large sample of Iranian elderly population. Methods Data were collected from Bushehr elderly health (BEH) program. A total of 3000 persons aged ≥60 years were selected through multistage random sampling. Hemoglobin values lower than 12 and 13 g/dL were considered as anemia for women and men, respectively. The cognitive function was measured using the Mini-cog test and Category fluency test (CFT), and the physical function was measured using handgrip strength (muscle strength), Relative handgrip strength (RHGS), and 4.57-m usual gait speed. Univariate and adjusted multivariate logistic regression and linear regression with Stata MP (version 15) were run, and a p-value of < 0.05 was used as statistically significant for all analyses. Results Among participants, 7.43% were anemic, and 115 (51.57%) simultaneously had anemia and cognitive disorder. There were significant associations between red blood cell count (RBC), hemoglobin (Hgb), platelet count (PLT), and hematocrit percentage (HCT) with cognitive impairment. Additionally, Hgb concentration was significantly associated with all physical measures (Mean handgrip, Relative handgrip, and usual gait speed) and late recall (mini-cog) among the whole participants. This association remained statistically significant after considering multi-cofounders. In contrast, after stratifying the participants by gender, the association between Hgb concentration and usual gait speed was decreased in both men and women; moreover, Hgb association with cognitive measures (category fluency test and late recall) was no longer significant (all p-values > 0.05). Conclusion There was a cross-sectional and significant association between anemia and functional variables (e.g., Relative and mean handgrip) in Iranian elderly population, whereas Semantic memory, Late recall, and walking were more affected by gender.

Comment on “Semantic memory impairment across the schizophrenia continuum: a meta-analysis of category fluency performance” by Tan et al.

I read with great interest the study by Tan et al. (2020) who conducted a meta-analysis of semantic fluency in people across the psychosis continuum. Among other analyses, the authors provide the first meta-analysis of clustering and switching on semantic fluency in patients with chronic schizophrenia, reporting that patients display significantly smaller “mean cluster sizes” compared to healthy subjects. I argue that there are serious concerns about the compatibility of the clustering data used in the meta-analysis.

Neuropsychological Impairments in Young Patients With Subclinical Hypothyroidism: A Case Control Study

Background: There is a lack of clarity about the cognitive dysfunction in young patients with subclinical hypothyroidism (SCH). This study was done to explore the neuropsychological impairments in young patients with SCH and compare them with euthyroid controls. Methods: Patients between 18 and 45 years of age and diagnosed with SCH were recruited. Controls were euthyroid age, gender, and education matched. All the cases and controls underwent a detailed neuropsychological assessment with a battery of tests validated for use in the age groups of 18 to 65 years. Results: Thirty-nine patients with a mean age of 30.3 ± 7.7 years (female:male ratio 12:1) and 23 controls (female:male ratio 21:2) with a mean age of 33.4 ± 7.1 years ( P = .24) were included in the study. The mean TSH value was 6.36 ± 1.3 mIU/L and 2.49 ± 1.03 mIU/L in cases and controls, respectively ( P < .001). The visual memory delayed recall was impaired, in 48.71% ( n = 19) and 21.7% ( n = 5) cases and controls, respectively ( P = .03). The category fluency test showed impairment in a greater number of cases (35.9%, n = 14) as compared to controls (13%, n = 3; P = .04). Conclusion: This study shows that younger patients with SCH have delayed visual memory recall and category fluency deficits, which are suggestive of dysfunction of the prefrontal cortex and temporal lobe in young SCH patients. These impairments may justify the treatment of young SCH patients with replacement therapy.