Normative study of the Stroop Color and Word Test in an educationally diverse elderly population

Regression-based normative data for the D-KEFS Color-Word Interference Test in Norwegian adults ages 20-85

Objective: The Delis-Kaplan Executive Function System (D-KEFS) Color-Word-Interference Test (CWIT; AKA Stroop test) is a widely used measure of processing speed and executive function. While test materials and instructions have been translated to Norwegian, only American age-adjusted norms from D-KEFS are available in Norway. We here develop norms in a sample of 1011 Norwegians between 20 and 85 years. We provide indexes for stability over time and assess demographic adjustments applying the D-KEFS norms. Method: Participants were healthy Norwegian adults from Center for Lifespan Changes in Brain and Cognition (LCBC) (n = 899), the Dementia Disease Initiation (n = 77), and Oslo MCI (n = 35). Using regression-based norming, we estimated linear and non-linear effects of age, education, and sex on the CWIT 1-4 subtests. Stability over time was assessed with intraclass correlation coefficients (ICC). The normative adjustment of the D-KEFS norms was assessed with linear regression models. Results: Increasing age was associated with slower completion on all CWIT subtests in a non-linear fashion (accelerated lowering of performance with older age). Women performed better on CWIT-1&3. Higher education predicted faster completion time on CWIT-3&4. The original age-adjusted norms from D-KEFS did not adjust for sex or education. Furthermore, we observed significant, albeit small effects of age on all CWIT subtests. ICC analyses indicated moderate to good stability over time. Conclusion: We present demographically adjusted regression-based norms and stability indexes for the D-KEFS CWIT subtests. US D-KEFS norms may be inaccurate for Norwegians with high or low educational attainment, especially women.

Minimal effect of long-term clonazepam on cognitive function in patients with isolated rapid eye movement sleep behavior disorder

STUDY OBJECTIVES

Despite its widespread use in patients with isolated rapid eye movement sleep behavior disorder (iRBD), the cognitive effect of clonazepam is uncertain. This study aimed to investigate the effect of cumulative clonazepam on cognitive function in patients with iRBD.

METHODS

Demographic characteristics, baseline cognitive test, and most recent cognitive test information were collected retrospectively. Based on cumulative clonazepam doses, patients were classified into 4 subgroups: group 1, < 365 mg (1 mg × 1 year); group 2, 365 mg to < 1,095 mg (1 mg × 3 years); group 3, 1,095 mg to < 2,190 mg (1 mg × 6 years); and group 4, 2,190 mg or more. Cognitive test scores were calculated as z scores adjusted for age, education, and sex.

RESULTS

This study included 101 patients with iRBD (63 males). Groups 1, 2, 3, and 4 had 14, 20, 32, and 35 patients, respectively. In within-group comparisons, follow-up Digit Span Backward test and the Trail Making Test A scores decreased in group 3, and follow-up Trail Making Test A and the Trail Making Test B scores decreased significantly in group 4. In the multiple regression analysis to determine influential factors on cognitive decline, cumulative clonazepam dose did not show a significant correlation with any cognitive domain. Follow-up cognitive function showed significant correlation only with baseline cognitive function.

CONCLUSIONS

Memory and executive functions tended to decline in patients with iRBD. However, there was no significant effect of cumulative clonazepam. There was no evidence that long-term use of clonazepam was related to cognitive decline in patients with iRBD.

CITATION

Lee M, Kim TK, Hong JK, Yoon I-Y. Minimal effect of long-term clonazepam on cognitive function in patients with isolated rapid eye movement sleep behavior disorder. J Clin Sleep Med. 2024;20(7):1173-1182.

Association Between Executive Dysfunction-Related Activities of Daily Living Disability and Clinical Dementia Rating Domain Patterns in Patients With Vascular Dementia and Age-Matched Patients With Alzheimer's Dementia

OBJECTIVE

Although the Clinical Dementia Rating (CDR) scale was originally developed to stage Alzheimer's dementia (AD), it is now used globally for various types of dementia. The aim of this study was to investigate the characteristic pattern of CDR domains and its association with neuropsychological findings and activities of daily living (ADL) in patients with vascular dementia (VaD) and patients with AD.

METHODS

We recruited very mild to mild VaD and AD patients who were age-matched among the first visitors to a dementia clinic. All subjects underwent a standardized clinical interview, physical and neurological examinations, and laboratory tests, including brain magnetic resonance imaging, according to the protocol of the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease assessment battery.

RESULTS

A total of 105 pairs of VaD and AD patients participated in this study. Although the adjusted scores on Korean version of the Mini-Mental State Examination were similar between the two groups, the VaD patients performed better on the Boston Naming Test, Word List Memory, Word List Recall, Word List Recognition, and Constructional Recall Test. However, the scores on global CDR, CDR sum of boxes, and ADL-related CDR domains were higher in VaD patients than in AD patients (p<0.001). The VaD patients also showed poor performances on the Disability Assessment for Dementia Scale, Frontal Assessment Battery, Executive Clock Drawing Task, and Stroop tests.

CONCLUSION

Despite similar general cognitive function and better memory function, patients with VaD tend to be staged as severer dementia on the CDR scale than patients with AD because of more impaired ADL associated with executive dysfunction.

Fully immersive virtual reality exergames with dual-task components for patients with Parkinson's disease: a feasibility study

BACKGROUND

Dual-task training in Parkinson's disease (PD) improves spatiotemporal gait parameters, cognition, and quality of life. Virtual reality (VR) has been used as a therapeutic tool for patients to participate in activities in a safe environment, engage in multisensory experiences, and improve motivation and interest in rehabilitation. This study aimed to investigate the feasibility of fully immersive VR exergames with dual-task components in patients with PD.

METHODS

We developed VR exergames (go/no-go punch game, go/no-go stepping game, and number punch game) to improve habitual behavior control using motor-cognitive dual-task performance in patients with PD. The participants underwent 10 sessions 2-3 times a week, consisting of 30 min per session. The Unified Parkinson's Disease Rating Scale, Timed Up and Go test (TUG) under single- and dual-task (cognitive and physical) conditions, Berg balance scale (BBS), Stroop test, trail-making test, and digit span were evaluated before and after intervention. The Simulator Sickness Questionnaire (SSQ) was used to assess VR cybersickness. Usability was assessed using a self-reported questionnaire.

RESULTS

Twelve patients were enrolled and completed the entire training session. The mean age of participants was 73.83 ± 6.09 years; mean disease duration was 128.83 ± 76.96 months. The Hoehn and Yahr stages were 2.5 in seven patients and 3 in five patients. A significant improvement was observed in BBS and Stroop color-word test (p = 0.047 and p = 0.003, respectively). TUG time and dual-task interferences showed positive changes, but these changes were not statistically significant. The median SSQ total score was 28.05 (IQR: 29.92), 13.09 (IQR: 11.22), and 35.53 (IQR: 52.36) before, after the first session, and after the final session, respectively; the differences were not significant. Overall satisfaction with the intervention was 6.0 (IQR: 1.25) on a 7-point Likert-type scale.

CONCLUSIONS

Fully immersive VR exergames combined with physical and cognitive tasks may be used for rehabilitation of patients with PD without causing serious adverse effects. Furthermore, the exergames using dual-task components improved executive function and balance. Further development of VR training content may be needed to improve motor and dual-task performances. Trial registration NCT04787549 ( https://clinicaltrials.gov/ct2/show/NCT04787549 ).

The effects of high versus low frequency of combined physical and cognitive training on cognitive function in older adults with cognitive decline: a quasi-experimental study

BACKGROUND

The effects of combined training can be affected by training characteristics such as frequency, session length, and duration. No empirical studies to date have directly compared how combined physical and cognitive training offered at different training frequencies affects cognitive function for older adults with cognitive decline. This study investigated the impact of training frequency on cognitive outcomes after combined physical and cognitive training for older adults with cognitive decline.

METHODS

A quasi-experimental study was conducted in community facilities and day care centers. The study assigned 89 older adults with cognitive decline into high-frequency (HF) or low-frequency (LF) training groups. The participants received 90- to 105-min training sessions, one (LF) or three (HF) times a week, for 12 weeks. Outcome measures were the Montreal Cognitive Assessment, Word List subtest of the Wechsler Memory Scale, Digit Symbol Substitution Test (DSST), and Stroop Color Word Test.

RESULTS

The HF group demonstrated greater improvement in immediate memory measured by the WL-IM (F = 8.7, P = 0.004) and in executive function measured by the SCWT (F = 5.89, P = 0.017) than the LF group. Compared with the HF group, the LF group showed a great improvement in delayed memory measured by the WL-DM (F = 9.62, P = 0.003). The HF and LF groups both increased in processing speed and global cognitive function.

CONCLUSIONS

Our study indicated that the different training frequency of combined physical and cognitive training may result in benefits on different cognitive functions in older adults with cognitive decline. These findings may assist clinical practitioners in choosing appropriate training frequencies based on various intervention purposes for the elderly with cognitive decline.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT03619577 (08/08/2018).

Development of a Cognitive Composite for Preclinical Alzheimer's Disease in Korean Older Adults

BACKGROUND

As tracking subtle cognitive declines in the preclinical stage of Alzheimer's disease (AD) is difficult with traditional individual outcome measures, need for cognitive composite for preclinical AD is widely recognized.

OBJECTIVE

We aimed to develop culturally appropriate cognitive composite that sensitively identifies subtle cognitive decline of preclinical AD in Korean older adults.

METHODS

A total 225 cognitively normal elderly individuals from the Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's Disease, were included. Tests of episodic memory, orientation, and executive function were carefully selected through review of previously established composites. Three candidate composites including Consortium to Establish a Registry for Alzheimer's Disease Word list recall (WLR), Logical memory (LM) II, and Mini-Mental status examination (MMSE) in common, and Letter fluency test (LF), category fluency test, or Stroop color and word test, were selected.

RESULTS

Student t-tests demonstrated that only the composite composed of WLR, LM II, MMSE, and LF (Composite 1) showed a significant difference in score decline over two-year follow-up period between Aβ positive and negative group (p = 0.03). Linear mixed model analyses also showed that the Aβ x time interaction effect was significant only for Composite 1 (p = 0.025). Based on the results, Composite 1 was chosen as the final cognitive composite for preclinical Alzheimer's disease (CPAD).

CONCLUSIONS

CPAD can be used to assess subtle cognitive decline of preclinical AD in clinical research settings, especially in Korean older adults. It also may be used for monitoring progression or treatment benefits in clinical practices.

The Stroop Task Sex Difference: Evolved Inhibition or Color Naming?

Previous research shows that women outperform men in the classic Stroop task, but it is not known why this difference occurs. There are currently two main hypotheses: (1) women have enhanced verbal abilities, and (2) women show greater inhibition. In two Stroop experiments, we examined the Inhibition hypothesis by adopting a procedure, often used in visual cognition paradigms, that induces a particular inhibitory component. So-called Negative Priming occurs when a distracting non-target stimulus on one trial becomes the target on the following trial. Results from our experiments showed that the degree to which this type of inhibition occurs within the Stroop effect is no different for men and women. This was the case irrespective of whether participants made a vocal response (Experiment 1; n = 64, 32 men and 32 women) or a manual response (Experiment 2; n = 64, 32 men and 32 women). These results do not therefore support the Inhibition hypothesis. We additionally review findings from a range of paradigms that can be seen as indexing the different components required for the Stroop task (e.g., distractor suppression). This review suggests that the sex effect is due to superior color naming ability in women.

Clinical manifestation of patients with isolated rapid eye movement sleep behavior disorder after modest-to-long disease duration

Study Objectives

Patients with isolated rapid eye movement (REM) sleep behavior disorder (iRBD) are known to be at risk of neurodegenerative diseases but the time process of neurodegeneration remains unclear and its ethnic difference is rarely discussed. The objective of this study was to investigate the clinical manifestation of iRBD according to disease duration in a Korean cohort.

Methods

Patients who had been diagnosed with iRBD for at least 5 years were tracked and those currently remaining as iRBD were invited for motor, autonomic, olfactory, color discrimination, and cognitive tests. Cross-sectional comparison between patients with iRBD with modest disease duration (5–9.9 years) and long disease duration (≥10 years) was conducted.

Results

There were total of 198 patients with iRBD (135 males, 68.2%) tracked, whose average age at diagnosis was 65.9 years. Thirty-three had developed parkinsonism and 17 had developed dementia, resulting in a phenoconversion risk of 35.7% at 10 years. Hazard rate showed a gradually increasing trend over time, beginning from 2.1 conversions per year to 8.5 at 10 years. Patients with iRBD with a long disease duration (n = 19) had slightly higher motor scores than those with a modest duration (n = 82). However, they showed no difference in the frequency of motor abnormality or other clinical markers.

Conclusions

There is a possible racial or geographical difference of phenoconversion risk. The progression of neurodegeneration might be very subtle in that patients with iRBD with longer disease duration do not necessarily show higher frequency of neurodegeneration markers.

Dual-Task-Based Drum Playing with Rhythmic Cueing on Motor and Attention Control in Patients with Parkinson's Disease: A Preliminary Randomized Study

Although there have been increasing reports regarding the effectiveness of dual-task interventions in rehabilitation, the scope of this research is limited to gross motor movement, such as gait among patients with Parkinson's disease (PD). To expand the dual-task paradigm to upper extremity motor and attention control in PD, drum playing with modulation of musical elements was attempted. The objective of this study was to evaluate the effects of a drum playing intervention with rhythmic cueing on upper extremity motor control and attention control in patients with PD. Twelve participants were randomly assigned to the drum playing intervention with rhythmic cueing group or the control group. The results showed that the drum playing with rhythmic cueing (DPRC) group significantly increased their sustained time of entrainment (45 BPM) and their latency time until entrainment from pretest to posttest. For the DPRC group, the latency time until entrainment was significantly improved, and improvements in cognitive measures were also found. This study shows that DPRC has great potential to improve upper extremity motor control and attention control and supports the development of new interventions that include this technique for rehabilitation in patients with PD.

Validation of the Korean Version of the Anosognosia Questionnaire for Dementia

OBJECTIVE

Anosognosia is a common phenomenon in individuals with dementia. Anosognosia Questionnaire for dementia (AQ-D) is a well-known scale for evaluating anosognosia. This study aimed to establish a Korean version of the AQ-D (AQ-D-K) and to evaluate the reliability and validity of the AQ-D-K in patients with Alzheimer's disease (AD) dementia.

METHODS

We translated the original English version of AQ-D into Korean (AQ-D-K). Eighty-four subjects with very mild or mild AD dementia and their caregivers participated. Reliability of AQ-D-K was assessed by internal consistency and one-month test-retest reliability. Construct validity and concurrent validity were also evaluated.

RESULTS

Internal consistencies of the AQ-D-K patient form and caregiver form were high (Cronbach alpha 0.95 and 0.93, respectively). The test-retest reliability of AQ-D-K measured by intra-class correlation coefficient was 0.84. Three factors were identified: 1) anosognosia of instrumental activity of daily living; 2) anosognosia basic activity of daily living; and 3) anosognosia of depression and disinhibition. AQ-D-K score was significantly correlated with the clinician-rated anosognosia rating scale (ARS), center for epidemiological studies-depression scale (CES-D) and state-trait anxiety inventory (STAI).

CONCLUSION

The findings suggest that the AQ-D-K is a reliable and valid scale for evaluating anosognosia for AD dementia patients using Korean language.

Stroop color and word test (SCWT): Normative data for the Lebanese adult population

The Stroop Color and Word Test (SCWT) is one of the most commonly used measures to assess multiple cognitive functions. Several studies have shown that SCWT performance is influenced by different demographic factors and have recommended the necessity of generating normative data in different cultures. The present study aims to explore the effect of gender, age, and education on SCWT scores and to generate normative data for the Lebanese healthy adults. A sample of 321 healthy participants aged 18 and above was recruited from different Lebanese regions. The SCWT was administered to the participants. A regression-based strategy was applied to generate normative data. The results showed a statistically significant effect of age and education on the SCWT scores whereas no significant effect for gender was found. An interactive calculator was created to calculate estimated Z-scores based on corresponding predictions of the linear regression model. The calculator also provides percentile ranks. The present study is the first to generate normative data for the SCWT test in Lebanon. Neuropsychologists in Lebanon will benefit from this outcome to improve the accurate detection of executive function deficits in clinical settings for the Lebanese adult population.

Validation of SATURN, a free, electronic, self-administered cognitive screening test

BACKGROUND

Cognitive screening is limited by clinician time and variability in administration and scoring. We therefore developed Self-Administered Tasks Uncovering Risk of Neurodegeneration (SATURN), a free, public-domain, self-administered, and automatically scored cognitive screening test, and validated it on inexpensive (<$100) computer tablets.

METHODS

SATURN is a 30-point test including orientation, word recall, and math items adapted from the Saint Louis University Mental Status test, modified versions of the Stroop and Trails tasks, and other assessments of visuospatial function and memory. English-speaking neurology clinic patients and their partners 50 to 89 years of age were given SATURN, the Montreal Cognitive Assessment (MoCA), and a brief survey about test preferences. For patients recruited from dementia clinics (n = 23), clinical status was quantified with the Clinical Dementia Rating (CDR) scale. Care partners (n = 37) were assigned CDR = 0.

RESULTS

SATURN and MoCA scores were highly correlated (P < .00001; r = 0.90). CDR sum-of-boxes scores were well-correlated with both tests (P < .00001) (r = -0.83 and -0.86, respectively). Statistically, neither test was superior. Most participants (83%) reported that SATURN was easy to use, and most either preferred SATURN over the MoCA (47%) or had no preference (32%).

DISCUSSION

Performance on SATURN-a fully self-administered and freely available (https://doi.org/10.5061/dryad.02v6wwpzr) cognitive screening test-is well-correlated with MoCA and CDR scores.

Cognitive function of older adults engaging in physical activity

BACKGROUND

Physical activity can be classified as open-skilled or closed-skilled. Open-skilled physical activity, such as tennis, require participants to perform within a dynamic setting and respond to unpredictable and frequent environmental changes throughout the activity. Closed-skilled types of physical activity, such as swimming, are predictable and self-directed. However, the benefits of cognitive function in these two types of physical activities to older adults are unknown. This study examined the effects of participation in open- and closed-skilled physical activity on the cognitive function of older adults.

METHODS

The study recruited a total of 61 participants aged 65 years and over. Participant recruitment was achieved by distributing flyers asking for volunteers in various sports venues. Participants self-reported to be without medical conditions affecting their physical and cognitive function. All participants underwent a two-hour assessment session involving the completion of seven standardised cognitive function assessments, which were used to assess a range of cognitive function.

RESULTS

Overall mean scores across all of the assessments showed superior performance for the open- or closed-skilled participants when compared with the no-physical-activity group. The results of 61 adults who participated in this study showed that closed-skilled physical activity was associated with better selective attention and visuospatial function while open-skilled physical activity was associated with better inhibition and cognitive flexibility function. No significant difference in self-regulation ability was found between the open- or closed-skilled groups.

CONCLUSIONS

Open-skilled physical activity was associated with better inhibition, visual tracking, and cognitive flexibility while closed-skilled physical activity was associated with better selective attention and visuospatial perception. The findings have important practical implications for the health and quality of life of ageing populations, knowing which particular types of physical activity might affect the cognitive function.

Combined Scores from the EncephalApp Stroop Test, Number Connection Test B, and Serial Dotting Test Accurately Identify Patients With Covert Hepatic Encephalopathy

BACKGROUND & AIMS

The EncephalApp Stroop test is a high-sensitivity but low-specificity test that has been used to identify patients with covert hepatic encephalopathy (CHE). We aimed to develop a new strategy to detect CHE, combining EncephalApp Stroop test score with scores from subtests of the psychometric hepatic encephalopathy scoring system (PHES).

METHODS

We performed a survey of 569 adult volunteers (229 men) in 9 communities in Shanghai, China, administering the EncephalApp Stroop test to determine the range of scores in the general population. Data from the standard PHES, including the number connection test-A, number connection test-B (NCT-B), line tracing test, serial dotting test (SDT), and digit symbol test, were used as the reference standard for diagnosis of CHE. A combination of the EncephalApp Stroop with subtests of the PHES was used to establish a new strategy for CHE diagnosis. We validated our findings using data from 160 patients with cirrhosis from 5 centers China.

RESULTS

We determined the range of EncephalApp Stroop test scores for the volunteers of different decades of age, education levels, and sexes. Age, education level, and sex were independently associated with EncephalApp Stroop test scores. A combination of scores from the EncephalApp Stroop test, the NCT-B, and the SDT identified patients with CHE with the highest level of accuracy, when the standard PHES was used as the reference standard. A combination of scores of 187 sec for the EncephalApp Stroop test and below -1 for the NCT-B or below -1 for the SDT identified patients with CHE with an area under the curve (AUC) of 0.86, 81.0% sensitivity, and 91.9% specificity, and 87.5% accuracy. In the validation cohort, these cutoff scores identified patients with CHE with an AUC of 0.88, 97.1% sensitivity, 79.3% specificity, and 86.9% accuracy. The average time to calculate this score was 374±140 sec, compared 424±115 sec for the entire PHES.

CONCLUSION

Scores from the EncephalApp Stroop test, NCT-B, and SDT identify patients with CHE with approximately 87% accuracy, and in a much shorter time than the standard PHES. This score combination could be a valid and convenient method for identifying patients with CHE. chictr.org.cn number, ChiCTR-EDC-17012007, ChiCTR1800019954.

Ageing stereotypes and prodromal Alzheimer's disease (AGING): study protocol for an ongoing randomised clinical study

INTRODUCTION

The number of older people diagnosed with amnestic mild cognitive impairment (aMCI), the prodromal state of Alzheimer's disease (AD), is increasing worldwide. However, some patients with aMCI never convert to the AD type of dementia, with some remaining stable and others reverting to normal. This overdiagnosis bias has been largely overlooked and gone unexplained. There is ample evidence in the laboratory that negative ageing stereotypes (eg, the culturally shared belief that ageing inescapably causes severe cognitive decline) contribute to the deteriorating cognitive performances of healthy older adults, leading them to perform below their true abilities. The study described here is intended to test for the first time whether such stereotypes also impair patients' cognitive performances during neuropsychological examinations in memory clinics, resulting in overdiagnosis of aMCI.

METHODS AND ANALYSIS

The ongoing study is a 4-year randomised clinical trial comparing patients' physiological stress and cognitive performances during neuropsychological testing in memory clinics. A total of 260 patients attending their first cognitive evaluation will be randomised to either a standard condition of test administration, assumed here to implicitly activate negative ageing stereotypes or a reduced-threat instruction condition designed to alleviate the anxiety arising from these stereotypes. Both groups will be tested with the same test battery and stress biomarkers. For 30 patients diagnosed with aMCI in each group (n=60), biomarkers of neurodegeneration and amyloidopathy will be used to distinguish between aMCI with normal versus abnormal AD biomarkers. A 9-month follow-up will be performed on all patients to identify those whose cognitive performances remain stable, deteriorate or improve.

ETHICS AND DISSEMINATION

This protocol has been approved by the French National Agency for Medicines and Health Products Safety and the Sud-Est I French Ethics Committee (2017-A00946-47). Results will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03138018.

Abnormal expression of circRNA_089763 in the plasma exosomes of patients with post‑operative cognitive dysfunction after coronary artery bypass grafting

Post-operative cognitive dysfunction (POCD) is a complication of the central nervous system characterized by mental disorders, anxiety, personality changes and impaired memory. POCD occurs frequently after coronary artery bypass grafting (CABG) and can severely affect quality of life for patients. To date, the development of POCD biomarkers remains a challenge. Alterations in the expression of non-coding RNAs from brain tissue and peripheral blood have been linked to POCD. The present study aimed to detect the differential circular RNAs (circRNAs) in plasma exosomes of patients with POCD after CABG. The relative expression levels of circRNAs were analyzed using circRNA microarray analysis in the plasma exosomes of patients with POCD. Differentially altered circRNAs (P<0.05, fold change >1.5) were validated by reverse transcription-quantitative PCR in the plasma exosomes of patients with POCD. The target genes of the microRNAs were predicted using bioinformatics analysis. The functions and signaling pathways of these target genes were investigated by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses. The microarray results indicated that the levels of nine circRNAs in patients with POCD were higher than those in the control subjects; and six circRNAs were at a lower level than those in control subjects. The RT-qPCR results from patients with POCD showed that only circRNA_089763 of the 15 circRNAs identified was significantly increased compared with control subjects. circRNA target gene prediction and functional annotation analysis showed significant enrichment in several GO terms and pathways associated with POCD. The present study provides evidence for the abnormal expression of POCD-induced circRNA_089763 in human plasma exosomes, as well as the involvement of POCD.

Clinical and Biomarker Characteristics According to Clinical Spectrum of Alzheimer's Disease (AD) in the Validation Cohort of Korean Brain Aging Study for the Early Diagnosis and Prediction of AD

We aimed to present the study design of an independent validation cohort from the Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's disease (AD) (KBASE-V) and to investigate the baseline characteristics of the participants according to the AD clinical spectrum. We recruited 71 cognitively normal (CN) participants, 96 with subjective cognitive decline (SCD), 72 with mild cognitive impairment (MCI), and 56 with AD dementia (ADD). The participants are followed for three years. The Consortium to Establish a Registry for AD scores was significantly different between all of the groups. The logical memory delayed recall scores were significantly different between all groups, except between the MCI and ADD groups. The Mini-Mental State Examination score, hippocampal volume, and cerebrospinal fluid (CSF) amyloid-β42 level were significant difference among the SCD, MCI, and ADD groups. The frequencies of participants with amyloid pathology according to PET or CSF studies were 8.9%, 25.6%, 48.3%, and 90.0% in the CN, SCD, MCI, and ADD groups, respectively. According to ATN classification, A+/T+/N+ or A+/T+/N- was observed in 0%, 15.5%, 31.0%, and 78.3% in the CN, SCD, MCI, and ADD groups, respectively. The KBASE-V showed a clear difference according to the AD clinical spectrum in neuropsychological tests and AD biomarkers.

Effects of smartphone-based memory training for older adults with subjective memory complaints: a randomized controlled trial

OBJECTIVES

We explored whether newly developed application (Smartphone-based brain Anti-aging and memory Reinforcement Training, SMART) improved memory performance in older adults with subjective memory complaints (SMC).

METHOD

A total of 53 adults (range: 50-68 years; 52.8% female) were randomized into either one of two intervention groups [SMART (n = 18) vs. Fit Brains® (n = 19)] or a wait-list group (n = 16). Participants in the intervention groups underwent 15-20 minutes of training per day, five days per week for 8 weeks. We used objective cognitive measures to evaluate changes with respect to four domains: attention, memory, working memory (WM), and response inhibition. In addition, we included self-report questionnaires to assess levels of SMC, depression, and anxiety.

RESULTS

Total WM quotient [t(17) = 6.27, p < .001] as well as auditory-verbal WM score [t(17) = 4.45, p < .001] increased significantly in the SMART group but not in the control groups. Self-reports of memory contentment, however, increased in the Fit Brains® group only [t(18) = 2.12, p < .05).

CONCLUSION

Use of an 8-week smartphone-based memory training program may improve WM function in older adults. However, objective improvement in performance does not necessarily lead to decreased SMC.

Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's Disease: Methodology and Baseline Sample Characteristics

OBJECTIVE

The Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's disease (KBASE) aimed to recruit 650 individuals, aged from 20 to 90 years, to search for new biomarkers of Alzheimer's disease (AD) and to investigate how multi-faceted lifetime experiences and bodily changes contribute to the brain changes or brain pathologies related to the AD process.

METHODS

All participants received comprehensive clinical and neuropsychological evaluations, multi-modal brain imaging, including magnetic resonance imaging, magnetic resonance angiography, [11C]Pittsburgh compound B-positron emission tomography (PET), and [18F]fluorodeoxyglucose-PET, blood and genetic marker analyses at baseline, and a subset of participants underwent actigraph monitoring and completed a sleep diary. Participants are to be followed annually with clinical and neuropsychological assessments, and biannually with the full KBASE assessment, including neuroimaging and laboratory tests.

RESULTS

As of March 2017, in total, 758 individuals had volunteered for this study. Among them, in total, 591 participants-291 cognitively normal (CN) old-aged individuals, 74 CN young- and middle-aged individuals, 139 individuals with mild cognitive impairment (MCI), and 87 individuals with AD dementia (ADD)-were enrolled at baseline, after excluding 162 individuals. A subset of participants (n=275) underwent actigraph monitoring.

CONCLUSION

The KBASE cohort is a prospective, longitudinal cohort study that recruited participants with a wide age range and a wide distribution of cognitive status (CN, MCI, and ADD) and it has several strengths in its design and methodologies. Details of the recruitment, study methodology, and baseline sample characteristics are described in this paper.

Cognitive performance norms from the Korean genome and epidemiology study (KoGES)

BACKGROUND

While normative data on neuropsychological performance provide baseline metrics for the assessment and diagnosis of mild cognitive impairment and dementia, a lack of comparative normative data in non-Caucasian populations makes it difficult to conduct similar evaluations and studies in individuals from diverse backgrounds. The current paper aims to provide normative data on a range of cognitive measures in a Korean general population sample and investigate various demographic and health variables associated with cognitive performance in this representative population.

METHOD(S)

The study population was 1,528 stroke and dementia-free individuals who participated in the Korean Genome and Epidemiology study (KoGES) (mean age 60.43 ± 7.30, 52.42% female). All participants underwent a comprehensive neuropsychological test battery that included verbal and visual memory, language, attention, and executive function measures. A health examination and a questionnaire-based interview were also administered.

RESULTS

The majority of cognitive test results were associated with age, education, and gender. In general, higher education and younger age was associated with better cognitive performance. Explained variance increased modestly in models that included measures of general health and depressive symptoms.

CONCLUSION

Normative data of cognitive performance in a community based Korean population are presented. These norms provide reference values in a non-Caucasian middle to older aged sample.

Subjective memory complaints in an elderly population with poor sleep quality

OBJECTIVES

The association between sleep disturbances and cognitive decline in the elderly has been putative and controversial. We evaluated the relation between subjective sleep quality and cognitive function in the Korean elderly.

METHOD

Among 459 community-dwelling subjects, 352 subjects without depression or neurologic disorders (mean age 68.2 ± 6.1) were analyzed in this study. All the participants completed the Korean version of the consortium to establish a registry for Alzheimer's disease neuropsychological battery (CERAD-KN) as an objective cognitive measure and subjective memory complaints questionnaire (SMCQ). Based on the Pittsburgh sleep quality index, two types of sleepers were defined: 'good sleepers' and 'poor sleepers'.

RESULTS

There were 192 good sleepers (92 men) and 160 poor sleepers (51 men). Poor sleepers reported more depressive symptoms and more use of sleep medication, and showed higher SMCQ scores than good sleepers, but there was no difference in any assessments of CERAD-KN. In the regression analysis, depressive symptoms and subjective sleep quality were associated with subjective memory complaints (β = 0.312, p < 0.001; β = 0.163, p = 0.005).

CONCLUSION

In the elderly without depression, poor sleep quality was associated with subjective memory complaints, but not with objective cognitive measures. As subjective memory complaints might develop into cognitive disorders, poor sleep quality in the elderly needs to be adequately controlled.

The Stroop Color and Word Test

The Stroop Color and Word Test (SCWT) is a neuropsychological test extensively used to assess the ability to inhibit cognitive interference that occurs when the processing of a specific stimulus feature impedes the simultaneous processing of a second stimulus attribute, well-known as the Stroop Effect. The aim of the present work is to verify the theoretical adequacy of the various scoring methods used to measure the Stroop effect. We present a systematic review of studies that have provided normative data for the SCWT. We referred to both electronic databases (i.e., PubMed, Scopus, Google Scholar) and citations. Our findings show that while several scoring methods have been reported in literature, none of the reviewed methods enables us to fully assess the Stroop effect. Furthermore, we discuss several normative scoring methods from the Italian panorama as reported in literature. We claim for an alternative scoring method which takes into consideration both speed and accuracy of the response. Finally, we underline the importance of assessing the performance in all Stroop Test conditions (word reading, color naming, named color-word).

Association of Cerebral Amyloidosis, Blood Pressure, and Neuronal Injury with Late-Life Onset Depression

Previous literature suggests that Alzheimer's disease (AD) process may contribute to late-life onset depression (LLOD). Therefore, we investigated the association of LLOD with cerebral amyloidosis and neuronal injury, the two key brain changes in AD, along with vascular risks. Twenty nine non-demented individuals who first experienced major depressive disorder (MDD) after age of 60 years were included as LLOD subjects, and 27 non-demented elderly individuals without lifetime experience of MDD were included as normal controls (NC). Comorbid mild cognitive impairment (MCI) was diagnosed in 48% of LLOD subjects and in 0% of NC. LLOD, irrespective of comorbid MCI diagnosis, was associated with prominent prefrontal cortical atrophy. Compared to NC, LLOD subjects with comorbid MCI (LLOD_MCI) showed increased cerebral ¹¹C-Pittsburg compound B (PiB) retention and plasma beta-amyloid 1–40 and 1–42 peptides, as measures of cerebral amyloidosis; and, such relationship was not observed in overall LLOD or LLOD without MCI (LLOD_woMCI). LLOD subjects, particularly the LLOD_woMCI, had higher systolic blood pressure (SBP) than NC. When analyzed in the same multiple logistic regression model that included prefrontal gray matter (GM) density, cerebral amyloidosis, and SBP as independent variables, only prefrontal GM density showed a significant independent association with LLOD regardless of MCI comorbidity status. Our findings suggest AD process might be related to LLOD via prefrontal neuronal injury in the MCI stage, whereas vascular processes—SBP elevation, in particular—are associated with LLOD via prefrontal neuronal injury even in cognitively intact or less impaired individuals.

Stroop Color-Word Interference Test: Normative data for the Latin American Spanish speaking adult population

OBJECTIVE

To generate normative data on the Stroop Test across 11 countries in Latin America, with country-specific adjustments for gender, age, and education, where appropriate.

METHOD

The sample consisted of 3,977 healthy adults who were recruited from Argentina, Bolivia, Chile, Cuba, El Salvador, Guatemala, Honduras, Mexico, Paraguay, Peru, and, Puerto Rico. Each subject was administered the Stroop Test, as part of a larger neuropsychological battery. A standardized five-step statistical procedure was used to generate the norms.

RESULTS

The final multiple linear regression models explained 14-36% of the variance in Stroop Word scores, 12-41% of the variance in the Stoop Color, 14-36% of the variance in the Stroop Word-Color scores, and 4-15% of variance in Stroop Interference scores. Although t-tests showed significant differences between men and women on the Stroop test, none of the countries had an effect size larger than 0.3. As a result, gender-adjusted norms were not generated.

CONCLUSIONS

This is the first normative multicenter study conducted in Latin America to create norms for the Stoop Test in a Spanish-Speaking sample. This study will therefore have important implications for the future of neuropsychology research and practice throughout the region.

Association Between Serum Triglycerides and Cerebral Amyloidosis in Cognitively Normal Elderly

OBJECTIVES

Although many preclinical studies have suggested the possible linkage between dyslipidemia and cerebral amyloid deposition, the association between serum lipid measures and cerebral amyloid-beta (Aβ) deposition in human brain is still poorly known. We aimed to investigate the association in cognitively normal (CN) elderly individuals.

DESIGN

Cross-sectional study.

SETTING

University hospital dementia clinic.

PARTICIPANTS

59 CN elderly.

MEASUREMENTS

The study measures included comprehensive clinical and neuropsychological assessment based on the CERAD protocol, magnetic resonance imaging and (11)C-labelled Pittsburgh Compound B positron emission tomography scans, and quantification for serum lipid biomarkers.

RESULTS

Multiple linear regression analyses showed that a higher serum triglycerides level was associated with heavier global cerebral Aβ deposition even after controlling age, sex, and apolipoprotein E ε4 genotype. Serum apolipoprotein B also showed significant positive association with global cerebral Aβ deposition, but the significance disappeared after controlling serum triglycerides level. No association was found between other lipid measures and global cerebral Aβ deposition.

CONCLUSIONS

The findings suggest that serum triglycerides are closely associated with cerebral amyloidosis, although population-based prospective studies are needed to provide further evidence of the causative effect of triglycerides on cerebral amyloidosis.

Heterogeneity of Regional Brain Atrophy Patterns Associated with Distinct Progression Rates in Alzheimer's Disease

We aimed to identify and characterize subtypes of Alzheimer’s disease (AD) exhibiting different patterns of regional brain atrophy on MRI using age- and gender-specific norms of regional brain volumes. AD subjects included in the Alzheimer's Disease Neuroimaging Initiative study were classified into subtypes based on standardized values (Z-scores) of hippocampal and regional cortical volumes on MRI with reference to age- and gender-specific norms obtained from 222 cognitively normal (CN) subjects. Baseline and longitudinal changes of clinical characteristics over 2 years were compared across subtypes. Whole-brain-level gray matter (GM) atrophy pattern using voxel-based morphometry (VBM) and cerebrospinal fluid (CSF) biomarkers of the subtypes were also investigated. Of 163 AD subjects, 58.9% were classified as the “both impaired” subtype with the typical hippocampal and cortical atrophy pattern, whereas 41.1% were classified as the subtypes with atypical atrophy patterns: “hippocampal atrophy only” (19.0%), “cortical atrophy only” (11.7%), and “both spared” (10.4%). Voxel-based morphometric analysis demonstrated whole-brain-level differences in overall GM atrophy across the subtypes. These subtypes showed different progression rates over 2 years; and all subtypes had significantly lower CSF amyloid-β_1–42 levels compared to CN. In conclusion, we identified four AD subtypes exhibiting heterogeneous atrophy patterns on MRI with different progression rates after controlling the effects of aging and gender on atrophy with normative information. CSF biomarker analysis suggests the presence of Aβ neuropathology irrespective of subtypes. Such heterogeneity of MRI-based neuronal injury biomarker and related heterogeneous progression patterns should be considered in clinical trials and practice with AD patients.

An updated Italian normative dataset for the Stroop color word test (SCWT)

The Stroop color and word test (SCWT) is widely used to evaluate attention, information processing speed, selective attention, and cognitive flexibility. Normative values for the Italian population are available only for selected age groups, or for the short version of the test. The aim of this study was to provide updated normal values for the full version, balancing groups across gender, age decades, and education. Two kinds of indexes were derived from the performance of 192 normal subjects, divided by decade (from 20 to 90) and level of education (4 levels: 3-5; 6-8; 9-13; >13 years). They were (i) the correct answers achieved for each table in the first 30 s (word items, WI; color items, CI; color word items, CWI) and (ii) the total time required for reading the three tables (word time, WT; color time, CT; color word time, CWT). For each index, the regression model was evaluated using age, education, and gender as independent variables. The normative data were then computed following the equivalent scores method. In the regression model, age and education significantly influenced the performance in each of the 6 indexes, whereas gender had no significant effect. This study confirms the effect of age and education on the main indexes of the Stroop test and provides updated normative data for an Italian healthy population, well balanced across age, education, and gender. It will be useful to Italian researchers studying attentional functions in health and disease.

Functional Neuroanatomical Correlates of The Frontal Assessment Battery Performance in Alzheimer Disease: A FDG-PET Study

BACKGROUND/OBJECTIVES

We aimed to elucidate the functional neuroanatomical correlates of Frontal Assessment Battery (FAB) performances by applying [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) to a large population of patients with Alzheimer disease (AD).

METHODS

The FAB was administered to 177 patients with AD, and regional cerebral glucose metabolism (rCMglc) was measured by FDG-PET scan. Correlations between FAB scores and rCMglc were explored using both region-of-interest-based (ROI-based) and voxel-based approaches.

RESULTS

The ROI-based analysis showed that FAB scores correlated with the rCMglc of the dorsolateral prefrontal cortices. Voxel-based approach revealed significant positive correlations between FAB scores and rCMglc which were in various cortical regions including the temporal and parietal cortices as well as frontal regions, independent of age, gender, and education. After controlling the effect of global disease severity with Mini-Mental State Examination score, significant positive correlation was found only in the bilateral prefrontal regions.

CONCLUSIONS

Although FAB scores are influenced by temporoparietal dysfunction due to the overall progression of AD, it likely reflects prefrontal dysfunction specifically regardless of global cognitive state or disease severity in patients with AD.

Brazilian preliminary norms and investigation of age and education effects on the Modified Wisconsin Card Sorting Test, Stroop Color and Word test and Digit Span test in adults

Executive functions are involved in a series of human neurological and psychiatric disorders. For this reason, appropriate assessment tools with age and education adjusted norms for symptom diagnosis are necessary.

Differences in functional brain connectivity alterations associated with cerebral amyloid deposition in amnestic mild cognitive impairment

Despite potential implications for the early detection of impending Alzheimer’s disease (AD), very little is known about the differences of large-scale brain networks between amnestic mild cognitive impairment (aMCI) with high cerebral amyloid-beta protein (Aβ) deposition (i.e., aMCI+) and aMCI with no or very little Aβ deposition (i.e., aMCI−). We first aimed to extend the current literature on altering intrinsic functional connectivity (FC) of the default mode network (DMN) and salience network (SN) from cognitively normal (CN) to AD dementia. Second, we further examined the differences of the DMN and the SN between aMCI−, aMCI+, and CN. Forty-three older adult (12 CN, 10 aMCI+, 10 aMCI−, and 11 AD dementia) subjects were included. All participants received comprehensive clinical and neuropsychological assessment, resting-state functional magnetic resonance imaging, structural MRI, and Pittsburgh compound-B-PET scans. FC data were preprocessed using multivariate exploratory linear optimized decomposition into independent components of FMRIB’s Software Library. Group comparisons were carried out using the “dual-regression” approach. In addition, to verify presence of gray matter volume changes with intrinsic functional network alterations, voxel-based morphometry was performed on the acquired T1-weighted data. As expected, AD dementia participants exhibited decreased FC in the DMN compared to CN (particularly in the precuneus and cingulate gyrus). The degree of alteration in the DMN in aMCI+ compared to CN was intermediate to that of AD. In contrast, aMCI− exhibited increased FC in the DMN compared to CN (primarily in the precuneus) as well as aMCI+. In terms of the SN, aMCI− exhibited decreased FC compared to both CN and aMCI+ particularly in the inferior frontal gyrus. FC within the SN in aMCI+ and AD did not differ from CN. Compared to CN, aMCI− showed atrophy in bilateral superior temporal gyri whereas aMCI+ showed atrophy in right precuneus. The results indicate that despite the similarity in cross-sectional cognitive features, aMCI− has quite different functional brain connectivity compared to aMCI+.

Clinical Spanish norms of the Stroop test for traumatic brain injury and schizophrenia

The Stroop Color-Word Test is a useful tool to evaluate executive attention and speed of processing. Recent studies have provided norms for different populations of healthy individuals to avoid misinterpretation of scores due to demographic and cultural differences. In addition, clinical norms may improve the assessment of cognitive dysfunction severity and its clinical course. Spanish normative data are provided for 158 closed traumatic brain injury (TBI) and 149 first-episode schizophrenia spectrum disorder (SCH) patients. A group of 285 Spanish healthy individuals (HC) was also considered for comparison purposes. Differences between groups were found in all Stroop scores with HC outperforming both clinical groups (p .3 in all cases). TBI patients scored lower than SCH patients in word-reading (p < .001 and d = .6), and color-naming conditions (p < .001 and d = .4), but not in the color-word condition (p = .34 and d = .03). However, SCH patients exhibited a higher interference effect as compared to TBI (p < .002 and d = .5). Three sets of norms stratified by age and education (HC), and by education (TBI and SCH) are presented for clinical use.

Beta-amyloid associated differential effects of APOE ε4 on brain metabolism in cognitively normal elderly

OBJECTIVE

Although apolipoprotein (APOE) ε4 allele is a well-established risk factor for late-onset Alzheimer disease (AD), the mechanism of its effects on AD pathogenesis is not fully understood. We aimed to investigate the effects of APOE genotype on regional cerebral glucose metabolism in cognitively normal (CN) elderly. We further tried to elucidate whether or not such effects are associated with beta-amyloid protein (Aβ) deposition.

METHODS

31 CN elderly participants underwent clinical examination, a range of neuropsychological tests, APOE genotyping, and Pittsburgh compound-B- and fluorodeoxyglucose-PET scans.

RESULTS

17 APOE ε4 carriers and 15 non-carriers were included. Both hypometabolic and hypermetabolic regions were observed in ε4 carriers compared with noncarriers when age, education, and sex were controlled. When the degree of global cerebral Aβ deposition was adjusted, the hypometabolic regions in the temporo-parietal area (i.e., BA 22 and 39) largely disappeared, whereas the hypermetabolic regions persisted in medial frontal and anterior temporal areas (i.e., BA 38, 11, and 39). Behaviorally, verbal episodic memory scores of APOE ε4 carriers were slightly lower than those of noncarriers, though still within normal range.

CONCLUSIONS

Our findings indicate that decreased cerebral glucose metabolism in the temporoparietal junction associated with APOE ε4 in CN elderly appears to be mediated by Aβ deposition, and the effect of APOE ε4 on hypermetabolism in the frontal and anterior temporal regions is independent of Aβ and may be associated with presence of compensatory mechanism in CN elderly with the ε4 allele.

Performance of an adult Brazilian sample on the Trail Making Test and Stroop Test

Objective

The Trail Making Test (TMT) and Stroop Test (ST) are attention tests widely used in clinical practice and research. The aim of this study was to provide normative data for the adult Brazilian population and to study the influence of gender, age and education on the TMT parts A and B, and ST cards A, B and C.

Methods

We recruited 1447 healthy subjects aged ≥18 years with an educational level of 0-25 years who were native speakers of Portuguese (Brazilian). The subjects were evaluated by the Matrix Reasoning and Vocabulary subtests of the Wechsler Adult Intelligence Scale-III, along with the TMTA, TMTB and ST A, B and C.

Results

Among the participants, mean intellectual efficiency was 103.20 (SD: 12.0), age 41.0 (SD: 16.4) years and education 11.9 (SD: 5.6) years. There were significant differences between genders on the TMTA (p=0.002), TMTB (p=0.017) and STC (p=0.024). Age showed a positive correlation with all attention tests, whereas education showed a negative correlation. Gender was not found to be significant on the multiple linear regression model, but age and education maintained their interference.

Conclusion

Gender did not have the major impact on attentional tasks observed for age and education, both of which should be considered in the stratification of normative samples.

Spectrum of cognitive impairment in Korean ALS patients without known genetic mutations

Background

Cognitive impairment is associated with a negative prognosis in amyotrophic lateral sclerosis (ALS), as well as with clinical specificity. We investigate neuropsychological function in ALS patients without known genetic mutations in a Korean tertiary clinic.

Methods

Three hundred and eighteen patients were enrolled in a prospective longitudinal cohort from September 2008 to February 2012. At the time of diagnosis of sporadic ALS, we carried out genetic and comprehensive neuropsychological tests on all patients, and collected demographic and clinical characteristics. Six cognitive domains, namely executive function, attention, language, calculation, visuospatial function and memory were evaluated. ANOVA and t-tests were used to assess differences in clinical characteristics and neuropsychological parameters between sporadic ALS patients. The Kaplan-Meier method and Cox proportional hazard model were used for survival analysis.

Results

One hundred and sixty-six patients were categorized into five subtypes: normal cognition (ALS pure), cognitive impairment (ALSci), behavioral impairment (ALSbi), frontotemporal dementia (ALS-FTD), and other types of dementia. Seventy patients (70/166, 42.2%) were cognitively or behaviorally impaired. Among the impaired patients, eight (8/166, 4.8%) had FTD-type dementia and one (1/166, 0.6%) was Alzheimer's disease-type. The ALS patients with cognitive impairment (ALSci) and with FTD (ALS-FTD) were more severely impaired in executive function, attention, language and memory than the cognitively intact ALS patients (ALS pure). In a survival analysis, ALSci (β = 1.925, p = 0.025) and ALS-FTD groups (β = 4.150, p = 0.019) tended to have shorter survival than the ALS pure group.

Conclusions

About half of ALS patients without known genetic variation have cognitive or behavioral impairment. ALS patients with cognitive abnormalities, especially FTD, have a poorer prognosis than those without cognitive impairment. In neuropsychological profiling, executive tasks were effective in identifying cognitive impairment in the ALS patients. It would be useful for clinicians to classify ALS according to neuropsychological profiles, and screen for subtle cognitive impairment.

Executive function changes before memory in preclinical Alzheimer's pathology: a prospective, cross-sectional, case control study

BACKGROUND

Early treatment of Alzheimer's disease may reduce its devastating effects. By focusing research on asymptomatic individuals with Alzheimer's disease pathology (the preclinical stage), earlier indicators of disease may be discovered. Decreasing cerebrospinal fluid beta-amyloid42 is the first indicator of preclinical disorder, but it is not known which pathology causes the first clinical effects. Our hypothesis is that neuropsychological changes within the normal range will help to predict preclinical disease and locate early pathology.

METHODS AND FINDINGS

We recruited adults with probable Alzheimer's disease or asymptomatic cognitively healthy adults, classified after medical and neuropsychological examination. By logistic regression, we derived a cutoff for the cerebrospinal fluid beta amyloid42/tau ratios that correctly classified 85% of those with Alzheimer's disease. We separated the asymptomatic group into those with (n = 34; preclinical Alzheimer's disease) and without (n = 36; controls) abnormal beta amyloid42/tau ratios; these subgroups had similar distributions of age, gender, education, medications, apolipoprotein-ε genotype, vascular risk factors, and magnetic resonance imaging features of small vessel disease. Multivariable analysis of neuropsychological data revealed that only Stroop Interference (response inhibition) independently predicted preclinical pathology (OR = 0.13, 95% CI = 0.04-0.42). Lack of longitudinal and post-mortem data, older age, and small population size are limitations of this study.

CONCLUSIONS

Our data suggest that clinical effects from early amyloid pathophysiology precede those from hippocampal intraneuronal neurofibrillary pathology. Altered cerebrospinal fluid beta amyloid42 with decreased executive performance before memory impairment matches the deposits of extracellular amyloid that appear in the basal isocortex first, and only later involve the hippocampus. We propose that Stroop Interference may be an additional important screen for early pathology and useful to monitor treatment of preclinical Alzheimer's disease; measures of executive and memory functions in a longitudinal design will be necessary to more fully evaluate this approach.

Demographically adjusted norms for Catalan older adults on the Stroop Color and Word Test

The Stroop Color and Word Test (SCWT) is a short test that is widely used in neuropsychological assessment to evaluate the executive aspects of attention control, information processing speed, selective attention, cognitive flexibility, and executive function in terms of the ability to inhibit a usual response in favor of an unusual response. The aim of this study was to create normative data from the SCWT adjusted for age, sex, and educational level for its clinical use in a population of 55 years of age and above. The SCWT was administered to a population-based sample of 2,151 participants aged 55 or older, and the effect of sex, age, and educational level was determined in the SCWT by means of linear regression models. Normative tables were created following the traditional method based on the stratification by relevant variables and on regression models.

Normative data for healthy older adults and an abbreviated version of the Stroop test

Normative data for the Kaplan version of the Stroop Test are presented for 153 healthy, cognitively intact older adults aged 50-89 years. Increasing age was associated with decreased performance on all three subtests (Stroop A, Stroop B, and Stroop C), while years of education was only associated with Stroop B performance. Hence the normative data were stratified by age into three groups (50-64, 65-74, 75-89). Completion times for the first half of each trial (half-time scores) were found to have good split-half reliability and correlated highly with the original full administration scores. Means and standard deviations for the half-time administration are also presented for this sample. The current study provides more comprehensive normative data for older adults than previously available, as well as normative information for half-time scores that may have future clinical utility as an alternative, abbreviated version of the Kaplan Stroop Test.

Spanish normative studies in young adults (NEURONORMA young adults project): norms for Stroop Color-Word Interference and Tower of London-Drexel University tests

INTRODUCTION

The Stroop Color-Word Interference Test (Stroop) measures cognitive flexibility, selective attention, cognitive inhibition and information processing speed. The Tower of London-Drexel University version test (TOL) assesses higher-order problem solving and executive planning abilities.

OBJECTIVE

In this study, as part of the Spanish normative studies project in young adults (NEURONORMA young adults), we present normative data for the Stroop and young adults TOL tests.

MATERIAL AND METHODS

The sample consisted of 179 participants who are cognitively normal and range in age from 18 to 49 years. Tables are provided to convert raw scores to scaled scores. Scores adjusted for sociodemographic factors were obtained by applying linear regression techniques.

RESULTS

No effects were found for age and sex in either test. Educational level impacted most of the Stroop test variables and some of the TOL scores (Total Moves score and Total Initiation Time score).

CONCLUSIONS

The norms obtained will be extremely useful in the clinical evaluation of young Spanish adults.

The influence of functional social support on executive functioning in middle-aged African Americans

Social support has a positive influence on cognitive functioning and buffers cognitive decline in older adults. This study examined the relations between social support and executive functioning in middle-aged adults. A community-based sample of African Americans completed the Interpersonal Support Evaluation List, a measure of functions of social support, and two measures of executive functioning, the Stroop Color and Word Test and the Wisconsin Card Sorting Test (WCST). Hierarchical regression analyses were used to explore the hypothesis that different facets of perceived social support influence performance on measures of executive functioning. After controlling for age, gender, and education, social support facets including belonging support, self-esteem support, appraisal support, and tangible support were significant predictors of Stroop performance. In addition, tangible support significantly predicted WCST performance. These findings add to previous literature on social support and cognition; however, findings for middle-aged adults are unique and suggest that social support has a positive influence on some executive functions in African Americans prior to old age.

Differential contribution of cognitive and psychomotor functions to the age-related slowing of speech production

Healthy elderly adults are slower to initiate and produce speech. However, the sources of the slowing remain poorly understood. The present study evaluates to which extent psychomotor and cognitive changes influence age-related slowing in speech generation. Four verbal tasks varying in degree of difficulty and cognitive demands were used to evaluate 30 young and 30 healthy elderly. Speed of word production was measured by reaction times and pronunciation durations. Stroop test and Digits backwards were used as cognitive predictors while the Purdue Pegboard and Finger Tapping were used as psychomotor predictors. The relative contribution of cognitive and psychomotor functioning was evaluated by hierarchical regression analyses and based on the processing speed hypothesis. Results showed that Vocabulary and psychomotor execution significantly explained a portion of the variance in RTs depending on type of verbal task. These variables explained 36% of the total variance in reading, 26% in naming, 31% in phonemic fluency and 47% in semantic fluency. Also, Vocabulary and psychomotor functions strongly predicted pronunciation speed. Conversely, tests related to executive functions and working memory were not significant predictors. These data demonstrate the importance of the interplay between Vocabulary and psychomotor decline on speed of language production among healthy elderly adults.

Neural Correlates of Stroop Performance in Alzheimer's Disease: A FDG-PET Study

Background/Aims

The Stroop test is commonly applied in elderly subjects for the evaluation of cognitive impairment related to Alzheimer's disease (AD) and related disorders. This study aimed to investigate the functional neural correlates of the Stroop performance in AD.

Methods

In 136 probable AD patients and 54 cognitively normal elderly, a [¹⁸F]-fluorodeoxyglucose positron emission tomography scan and Stroop Color Word Test (SCWT) were performed. The correlations between the Stroop effect, which was measured by 6 different scoring methods, and regional cerebral glucose metabolism (rCMglc) were explored using a region-of-interest (ROI) approach and voxel-based analysis.

Results

Among 6 Stroop interference measures, only 2 scores, including the SCWT color-word (CW) score, were significantly correlated with rCMglc of the dorsolateral prefrontal and anterior cingulate ROIs. Voxel-based analysis revealed significant positive correlations between SCWT CW scores and rCMglc in the inferior parietal lobule, middle temporal gyrus and middle frontal gyrus. Such correlations remained significant only in the less severe AD group.

Conclusion

In AD patients, the Stroop effect depends on the functional integrity of the prefrontal cortices. Some parietotemporal regions also appear to be responsible for the Stroop effect in AD individuals.