Higher Digit Symbol Substitution Test Scores Research Articles

Caffeine intake improves the cognitive performance of patients with chronic kidney disease.

ObjectiveCognitive impairment is a common complication of chronic kidney disease (CKD). Caffeine intake has been reported to improve cognitive performance in several studies. However, whether the benefits of caffeine intake on cognitive function apply to patients with CKD remains unknown.MethodsWe performed a retrospective cross-sectional study based on the National Health and Nutrition Examination Survey (NHANES). The data of CKD subjects and non-CKD subjects from NHANES 2011−2014 were analyzed. Propensity score matching (PSM) was performed based on age, sex, diabetes, cancer, educational level, energy intake and protein intake to select subjects. The Consortium to Establish a Registry for Alzheimer’s Disease Word Learning Test (CERAD-WL), the CERAD Word List Recall Test (CERAD-DR), the Animal Fluency Test (AF) and the Digit Symbol Substitution Test (DSST) were used, whereby the occurrence of cognitive impairment was identified. Logistic regression models were performed to evaluate the association between caffeine intake and cognitive performance in CKD and non-CKD participants. Stratified analyses according to the stage of CKD and the urinary albumin/creatinine ratio levels were performed. Plot curves were then generalized to present a non-linear relationship, and the inflection point for each non-linear model was obtained by using a recursive algorithm.ResultsCognitive impairment was more prevalent in CKD patients than in non-CKD subjects. For CKD patients, caffeine intake was associated with higher CERAD-WL, CERAD-DR, AF and DSST scores. For non-CKD subjects, caffeine intake was associated with higher DSST scores only. Subgroup analysis revealed that caffeine only benefited the cognitive function of patients with CKD stages 2 and 3. The analysis showed non-linear relationships of caffeine intake and cognitive function for both CKD and non-CKD subjects. The inflection point of caffeine intake for CKD patients was 279 mg/day.ConclusionThe recommended dose of caffeine intake to improve the cognitive function of CKD patients is ≤279 mg/day.

Abstract P013: Associations Between Diastolic Blood Pressure With Cognitive Functioning: Differences By Systolic Blood Pressure Among US Adults.

Introduction: While elevated systolic blood pressure (BP) is a known contributor to cognitive decline, the role of elevated diastolic BP (DBP) as an independent risk factor for cognitive decline is less clear, especially in relationship to systolic BP (SBP) levels. Objectives: To characterize the association between DBP and cognitive functioning at differing levels of SBP. Methods: The National Health and Nutrition Examination Survey is a nationally representative survey of U.S. adults conducted annually. Our sample included data from participants of the 1999-2002 and 2011-2014 cycles, age 60+, with measured BP and cognition (N=5,480). BP was measured three times manually with a standardized sphygmomanometer and averaged. Cognitive functioning was measured using the digit symbol substitution test (DSST), a measure of executive functioning (with higher scores indicating better performance: range 0-100). We tested for a statistical interaction between SBP and DBP. To determine whether DBP was associated with DSST score, we used linear regression analyses and stratified by categories of SBP. Models were adjusted for: age, sex, race, education, income, insurance, marital status, BMI, diabetes, BP medication, and cholesterol. All analyses accounted for the complex survey design. Results: Almost half (48.9%, SE=1.1) of the sample was aged 60-69 with 55.3% (SE=0.7) female. The association between DBP and cognitive functioning differed by SBP (p<0.01), leading to stratified analyses. Every 5 mmHg increment of DBP was associated with significantly higher DSST scores among individuals with SBP 110-119 mmHg only (beta: 0.76, 95% CI: 0.24, 1.27). Results were not significant among participants with SBP < 110mmHg (beta: 0.84, 95% CI: -0.09, 1.77), SBP 120-129 mmHg (beta: 0.09, 95% CI:-0.49, 0.69), SBP 130-140 mmHg (beta: 0.29, 95% CI: -0.10, 0.69), SBP 140-159 mmHg (beta: 0.23, 95% CI: -0.15, 0.61), or SBP ≥160mmHg (beta: -0.08, 95% CI: -0.56, 0.39). Conclusion: In a population-based sample of older US adults, higher DBP was associated with greater executive functioning only among individuals with normal SBP. The results suggest that at non-hypertensive levels of SBP, higher DBP may not be detrimental for cognitive performance.

Association between Serum Lipid Parameters and Cognitive Performance in Older Adults.

(1) Background: Previous studies have suggested the association between lipid profiles and cognitive function in older adults. However, they generated inconsistent results. We aim to determine the relationship between lipid profiles and cognitive performance in older adults. (2) Methods: We used the 2011–2014 National Health and Nutrition Examination Survey. This study included 2215 participants who were aged more than 60 years old and free of coronary heart disease or stroke. Lipid profiles included total cholesterol (TC), low density lipid cholesterol (LDL), high density lipid cholesterol (HDL), and triglyceride (TG). Cognitive function was assessed using the digit symbol substitution test (DSST). (3) Results: Positive correlations of DSST were observed with TC (r = 0.111; p < 0.0001), HDL (r = 0.127; p < 0.0001), and LDL (r = 0.107; p = 0.0005). However, there was no significant relationship between TG and DSST. A one-unit increase in HDL was associated with an increase in DSST score (beta coefficient: 0.036; p = 0.018); but the association was not significant for LDL, TG, and TC. In the categorical analysis, the high HDL group had a higher DSST score than the low HDL group (beta = 3.113; p < 0.0001) and the low TG group was more likely to show a lower DSST score than the high TC group (beta = −1.837; p = 0.0461). However, LDL and TC showed no statistically significant associations. Moreover, HDL was only associated with a 0.701 times increased risk of cognitive impairment (95% CI = 0.523–0.938) in the logistic regression analysis. (4) Conclusions: Higher blood concentrations of HDL levels were positively associated with DSST scores in older adults. We suggest that the high levels of HDL may be a protective factor against cognitive impairment.

Association of magnesium intake and vitamin D status with cognitive function in older adults: an analysis of US National Health and Nutrition Examination Survey (NHANES) 2011 to 2014.

Reduced cognitive function associated with aging has gained increasing attention as the US population ages. Magnesium plays a critical role in vitamin D biosynthesis and metabolism; and deficiencies in magnesium and vitamin D show associations with poor cognition. However, no study has examined their interaction. This study aimed to evaluate the associations of magnesium intake and serum 25-hydroxyvitamin D (25(OH)D) concentrations, indicating vitamin D status, with cognition, and interaction between these nutrients in older adults. Based on the National Health and Nutrition Survey (NHANES) 2011-2014, the study included 2466 participants aged ≥ 60years who completed the Digit Symbol Substitution Test (DSST) and had data available on serum 25(OH)D and magnesium intake. Cognitive impairment was defined as a DSST score lower than the lowest quartile. Serum 25(OH)D concentrations were measured by HPLC-tandem mass spectrometry. Higher total magnesium intake was independently associated with higher DSST scores (highest quartile vs lowest: β = 4.34, 95% CI 1.14-7.54). The association of total magnesium intake with high DSST score was primarily observed among women, non-Hispanic whites, physically active participants and those with sufficient vitamin D status, although the interactions were not significant. The odds of cognitive impairment was reduced with increasing intake of total magnesium (p trend < 0.01) and higher level of serum 25(OH)D (p trend = 0.05). Findings suggest that high magnesium intake alone may improve cognitive function in older adults, and the association may be stronger among subjects with sufficient vitamin D status. Further studies are needed to confirm these findings.

Normative data for the Digit Symbol Substitution Test in a population-based sample aged 65–79 years: Results from the German Health Interview and Examination Survey for Adults (DEGS1)

ABSTRACTObjective: To provide normative data for the Digit Symbol Substitution Test (DSST) of the Wechsler Adult Intelligence Scale, 3rd edition (WAIS-III) in a population-based sample of community-dwelling older adults in Germany according to age, sex, and level of education.Method: The sample comprised 1385 participants aged 65–79 years from the nationwide representative ‘German Health Interview and Examination Survey for Adults’ (DEGS1, 2008–2011). Participants with known cognitive impairment or dementia, other medical conditions affecting cognition, or currently using psychotropic drugs were excluded. Educational level was categorized as low, medium, and high according to the Comparative Analyses of Social Mobility in Industrial Nations (CASMIN) scale. Normative values for the DSST according to age, sex, and level of education were estimated by multiple linear regression using population weights.Results: Mean age was 71.1 years, 48.6% were men and low, medium, and high education levels were 62.8, 24.6, and 12.6%, respectively. Younger age, female sex, and higher level of education were significantly associated with higher DSST scores. Regression-based normative data for the DSST is provided according to age, sex, and level of education. In addition, a normative score calculator is provided.Conclusions: These are the first age-, sex-, and education-specific normative data for older individuals for the DSST of the WAIS-III in Germany. These normative data will enable future population-level analyses on impaired cognitive function according to DSST.

The fat-but-fit paradigm within the context of cognitive function.

To evaluate the association of the Fat-but-Fit paradigm with cognitive function in an older adult population. Data from the 1999-2002 National Health and Nutrition Examination Survey were used (N = 2,336 adults 60-85 yrs). Physical activity was assessed via open-ended questions asking about participation in 48 leisure-time activities over the previous 30 days. Using Metabolic Equivalent of Task calculations for each activity, participants were classified as either active or inactive. Participants were then classified into one of six groups (Normal BMI and Inactive [referent], Overweight BMI and Inactive, Obese BMI and Inactive, Normal BMI and Active, Overweight BMI and Active, Obese BMI and Active), based on their activity status and body mass index (BMI). The Digit Symbol Substitution Test (DSST) was employed to assess cognitive function. Compared to those who had a normal BMI and were inactive (referent), those who had a normal BMI and were active had a 4-unit higher DSST score (β = 4.0; 95% CI: 1.0-6.9; P = 0.009); those with an overweight BMI and active had a 4.5-unit higher DSST score (β = 4.5; 95% CI: 1.3-7.6; P = 0.008); and those who had an obese BMI and active had a 3.7-unit higher DSST score (β = 3.7; 95% CI: 0.96-6.4; P = 0.01). Being active, regardless of weight classification (normal, overweight, or obese) was positively associated with cognitive function in this sample of older adults. This suggests that perhaps the best strategy to promote cognitive health in this population may be to encourage adequate levels of physical activity.

Free-Living Physical Activity, Executive Function, and Kidney Disease

Objective: We evaluated the specific association between physical activity and cognition among older adults with kidney disease in the United States. Methods: Data from the 1999-2002 National Health and Nutrition Examination Survey (NHANES) was used to identify 66 older adults, between 60-85 years, with complete data on selected study variables. Diagnosis of kidney disease was assessed via self-report. Participation in physical activity was determined from self-report data. The DSST (Digit Symbol Substitution Test) was used to assess participant executive cognitive functioning tasks of pairing and free recall. Individuals were excluded if they had missing data on the study variables assessed, or if they self-reported having coronary artery disease, congestive heart failure, stroke or a heart attack. Results: Physical activity was associated with higher cognitive performance in this sample. After adjustments, those meeting MVPA guidelines (vs. not) had an 8.77 higher DSST score (β=8.77; 95% CI: 1.65-15.89; P=0.02). Also, after adjustments, for every 1 MET-min-month increase in MVPA, participants had a 0.0007 DSST increase (β=0.0007; 95% CI: -0.0001-0.001; P=0.08), although this result was not statistically significant. Conclusion: In this sample of older adults with kidney disease, there was a positive association between physical activity participation and higher levels of cognitive functioning.

Combined associations of sedentary behavior and cardiorespiratory fitness on cognitive function among older adults

BackgroundSedentary behavior, cardiorespiratory fitness, cognition and age are interrelated and associated with cardiovascular function. No study, however, has specifically evaluated the independent and combined associations of cardiorespiratory fitness and sedentary behavior on cognition, which was this study's purpose. MethodsData from the 1999–2002 NHANES were used (N=2451; 60–85yrs). Sedentary behavior was assessed via self-report; cardiorespiratory fitness was assessed from a medical-related algorithm; and cognition function was assessed from the Digit Symbol Substitution Test (DSST). ResultsBeing in the bottom quartile for sedentary behavior (β=2.13; 95% CI: 0.49–3.77; P=0.01) and the top quartile for cardiorespiratory fitness (β=7.48; 95% CI: 5.4–9.5; P<0.001) were independently associated with higher cognitive function. In the additive model, those with an index score of 1 (vs. 0) and 2 (vs. 0), respectively, had a 3.87 (β=3.87; 95% CI: 1.76–5.98; P=0.001) and 10.40 (β=10.4; 95% CI: 7.31–13.5; P<0.001) higher DSST score. ConclusionHigh cardiorespiratory fitness and low sedentary behavior were jointly associated with the highest cognitive function. This has important cardiovascular implications as a progression of neurocognitive impairment is associated with increasingly severe manifestations of cardiovascular disease.

Physical Activity and Cognitive Function among Older Adults with Congestive Heart Failure Patients

Objective: Research among the general population demonstrates that regular participation in physical activity is associated with enhanced cognitive function. Although less investigated among congestive heart failure patients, this is important to consider among congestive heart failure patients because this population exhibits less physical activity behavior, worse executive function, psychomotor speed and memory-related cognitive function. The purpose of this brief report was to examine the association between physical activity and cognitive function among congestive heart failure patients. Methods: Data from the 1999-2002 population-based National Health and Nutrition Examination Survey was used. Moderate-to-vigorous physical activity (MVPA) and congestive heart failure status were subjectively assessed, with cognitive function assessed via the Digit Symbol Substitution Test (DSST). Results: 133 participants (Agerange = 60-85; Agemean = 72.8; 51.3% male; 83.7% white) had congestive heart failure and complete data on the study variables. In a weighted multivariable linear regression accounting for the complex survey design employed in NHANES, congestive heart failure patients who engaged in any level of MVPA in the past month had a significantly higher DSST score (βadjusted = 5.40; 95% CI: 0.58-10.22; P=0.03). Conclusion: Physical activity was positively associated with cognitive function among congestive heart failure patients, which provides suggestive evidence that physical activity may help to preserve cognitive function among older adults with evidence of congestive heart failure.

Association Between Cerebellar Gray Matter Volumes, Gait Speed, and Information-Processing Ability in Older Adults Enrolled in the Health ABC Study

The cerebellum plays an important role in mobility and cognition. However, it is unclear which regions of the cerebellum are associated with gait speed and information-processing ability in older adults without overt brain damage. Cross-sectional associations between cerebellar gray matter volumes (GMV), gait speed, and information-processing ability were explored in 231 community-dwelling adults (mean age: 83 years, 48% black, 58% female). We measured gait speed on an automated walkway and information-processing ability on the Digit Symbol Substitution test (DSST). Total and regional cerebellar GMV was measured on 3T-magnetic resonance imaging. Lobar GMV of the cerebellum, obtained by an automated parcellation process, were aggregated based on the cognitive (lobules VI, VII, VIII and crus I, II), sensorimotor (lobules II, IV, V), and vestibular (lobules IX and X) functions ascribed to the cerebellar regions. Larger cerebellar GMV correlated with faster gait speed and superior DSST scores (both p < .001) independent of age, gender, atrophy, and small vessel disease. After adjusting for age, gender, and atrophy, larger cognitive cerebellar GMV correlated with both faster gait speed (p = .04) and higher DSST scores (p < .001), larger sensorimotor cerebellar GMV correlated significantly with DSST alone (p = .02), and the vestibular cerebellar GMV with neither. The association between cognitive cerebellar GMV and gait speed was no longer significant after adjusting for DSST score in the linear regression models. The relationship between gait speed and cerebellar GMV is influenced by information-processing ability, and this relationship is stronger in subregions ascribed to cognitive than vestibular or sensorimotor functions.

Early Age-Related Macular Degeneration, Cognitive Function, and Dementia

To describe the association of cognitive function and dementia with early age-related macular degeneration (AMD) in older individuals. This population-based study included 2,088 persons aged 69 to 97 years who participated in the Cardiovascular Health Study. The AMD was assessed from retinal photographs based on a modified Wisconsin AMD grading system. Cognitive function was assessed using the Digit Symbol Substitution Test (DSST) and the Modified Mini-Mental State Examination. Participants were also evaluated for dementia using detailed neuropsychological testing. After controlling for age, sex, race, and study center, persons with low DSST scores (lowest quartile of scores, < or =30) were more likely to have early AMD (odds ratio, 1.38; 95% confidence interval, 1.03-1.85) than were persons with higher DSST scores. In analyses further controlling for education, systolic blood pressure, total cholesterol level, diabetes mellitus, smoking status, and apolipoprotein E genotype, this association was stronger (odds ratio, 2.00; 95% confidence interval, 1.29-3.10). There was no association of low Modified Mini-Mental State Examination scores, dementia, or Alzheimer disease with early AMD. In this older population, cognitive impairment may share common age-related pathogenesis and risk factors with early AMD.