Verbal and visuospatial executive functions in healthy elderly: The impact of education and frequency of reading and writing

From functional neuroimaging to neurostimulation: fNIRS devices as cognitive enhancers

Functional near-infrared spectroscopy (fNIRS) relies on near-infrared (NIR) light for changes in tissue oxygenation. For decades, this technique has been used in neuroscience to measure cortical activity. However, recent research suggests that NIR light directed to neural populations can modulate their activity through "photobiomodulation" (PBM). Yet, fNIRS is being used exclusively as a measurement tool. By adopting cognitive tests sensitive to prefrontal functioning, we show that a 'classical' fNIRS device, placed in correspondence of the prefrontal cortices of healthy participants, induces faster RTs and better accuracy in some of the indexes considered. A well-matched control group, wearing the same but inactive device, did not show any improvement. Hence, our findings indicate that the 'standard' use of fNIRS devices generates PBM impacting cognition. The neuromodulatory power intrinsic in that technique has been so far completely overlooked, and future studies will need to take this into account.

Understanding the Episodic Memory and Executive Functioning Axis Impairment in MCI Patients: A Multicenter Study in Comparison with CSF Biomarkers

BACKGROUND

This study aimed to explore the association between a verbal learning task that evaluates the potential mutual dependency between memory and executive functions (i.e., the Test of Memory Strategies, TMS) and cerebrospinal fluid (CSF) Alzheimer's Disease (AD) biomarkers.

METHODS

A sample of 47 mild cognitive impairment (MCI) participants from Poland and Spain were classified according to the Erlangen Score Diagnostic Algorithm (ESA) into CSF- (n = 16) and CSF+ (n = 31) groups. Correlation analyses between TMS word-list conditions and CSF biomarkers were conducted. Additionally, an analysis of covariance was performed to define the effect on ESA classification in the sample, using as a covariable the country of origin of the participants.

RESULTS

Significant associations between the TMS-3 condition and Aβ42, t-tau, and p-tau were observed for the whole sample. In addition, the CSF- participants obtained higher cognitive performance in TMS-3 compared to the CSF+ group. This outcome persisted if the groups were based on Aβ42 scores, but not t-tau or p-tau values.

CONCLUSIONS

These findings could indicate that poor performance on verbal learning tests may be affected by executive dysfunctions. Therefore, future intervention plans focused on training executive functions would be of interest to improve the ability of MCI patients to encode and organize information.

Genome-wide association study of population-standardised cognitive performance phenotypes in a rural South African community

Cognitive function is an indicator for global physical and mental health, and cognitive impairment has been associated with poorer life outcomes and earlier mortality. A standard cognition test, adapted to a rural-dwelling African community, and the Oxford Cognition Screen-Plus were used to capture cognitive performance as five continuous traits (total cognition score, verbal episodic memory, executive function, language, and visuospatial ability) for 2,246 adults in this population of South Africans. A novel common variant, rs73485231, reached genome-wide significance for association with episodic memory using data for ~14 million markers imputed from the H3Africa genotyping array data. Window-based replication of previously implicated variants and regions of interest support the discovery of African-specific associated variants despite the small population size and low allele frequency. This African genome-wide association study identifies suggestive associations with general cognition and domain-specific cognitive pathways and lays the groundwork for further genomic studies on cognition in Africa.

Does the frequency of reading and writing habits contribute to executive functions, intelligence, and learning in adolescents with healthy development?

The influence of the frequency of reading and writing habits (FRWH) on cognition has been investigated by several studies in the literature. However, the implications of FRWH on executive development, intelligence, and academic achievement are not yet clear in adolescents with healthy development. The aim was to verify whether there are differences in executive functions, intelligence, and academic achievement between adolescents with high and low FRWH. Moreover, we aimed to investigate if there are differences in the parental FRWH between adolescents with high and low FRWH. The sample was composed of 47 healthy adolescents, n = 24 with high FRWH and n = 23 with low FRWH. Adolescents with higher FRWH had better performance on measures of vocabulary, Speech Act analysis, and Oral Narrative Discourse. Therefore, a high FRWH has a positive influence on the cognitive development of healthy adolescents, especially with regard to pragmatic language. However, adolescents with low FRWH performed better than those with a high FRWH on an automatic counting task. The interpretation of cognitive performance and academic achievement scores in neuropsychological assessment should consider the FRWH of parents and adolescents. This factor should be targeted by early stimulation interventions to help adolescents achieve the highest possible levels of global development.

Norm scores of cancelation and bisection tests for unilateral spatial neglect: data from a Brazilian population

OBJECTIVE

Unilateral spatial neglect (USN) results in a consistent and exaggerated spatial asymmetry in the processing of information about the body or space due to an acquired brain injury. There are several USN tests for clinical diagnosis, but none of them are validated in Brazil. The aim was to obtain normative values from a healthy sample in Brazil and to evaluate the effects of demographic variables on USN tests.

METHODS

This was a cross-sectional study performed with 150 neurologically healthy individuals. USN was evaluated using the line cancelation (LC), star cancelation (SC), and line bisection (LB) tests in the A3 (29.7 x 42.0 cm) sheet format.

RESULTS

In LC, 143 participants had 0 omissions, and the occurrence of failure was significantly associated with aging (OR=1.1[1.02-1.2]; p=0.012). In SC, 145 participants had fewer than 1 omission, and the occurrence of failure was significantly associated with aging (OR=1.07[1.03-1.11]; p<0.001). In LB, deviations were the lowest for those with the highest level of education (r=0.20; p=0.015), and the deviation was 9.5 mm.

CONCLUSION

The cutoff points presented in this study may be indicative of USN, but due to performance differences based on age, we suggest using different norm scores for different age groups. These norm scores can be used in the clinic immediately for USN diagnosis.

Age, education and gender effects on Wisconsin card sorting test: standardization, reliability and validity in healthy Argentinian adults

The Wisconsin Card Sorting Test (WCST) is a widely used neuropsychological assessment of executive functioning. The aim of this study was to provide norm values and analyze the psychometric properties of WCST in healthy Argentinian adults aged from 18 to 89 years old (N = 235). Descriptive statistics are reported as means, standard deviations and percentiles, with the effects of age, education and gender being investigated by ANOVA, and with the effect sizes being calculated. The psychometrics were studied using the WCST structure, reliability, convergent validity, and discriminant validity, and WCST norms adjusted for age and educational level are proposed. This instrument is a reliable and valid tool for the assessment of executive functions. However, as the age- and educational-related effects were demonstrated, these characteristics need to be considered before interpreting WCST scores. Regarding gender, no differences were found. Our results expand the geographical and sociocultural applicability of WCST.

Distinguishing mild cognitive impairment from healthy aging and Alzheimer's Disease: The contribution of the INECO Frontal Screening (IFS)

Executive functions are affected differently in healthy aging, Mild Cognitive Impairment (MCI) and Alzheimer's Disease (AD), and evaluating them is important for differential diagnosis. The INECO Frontal Screening (IFS) is a brief neuropsychological screening tool, developed to assess executive dysfunction in neurodegenerative disorders.

GOALS

We aimed to examine whether and how MCI patients can be differentiated from cognitively healthy controls (HC) and mild to moderate AD patients based on IFS performance. We also explored how IFS scores are associated with age, years of education, and depressive/anxious symptoms (as assessed by the Hospital Anxiety and Depression Scale).

METHOD

IFS total scores were compared between 26 HC, 32 MCI and 21 mild to moderate AD patients. The three groups were matched for age and education. The Area Under the Curve (AUC) was analyzed and optimal cut-offs were determined.

RESULTS

Healthy participants had higher IFS scores than both clinical groups, and MCI patients had higher scores than AD patients. IFS showed high diagnostic accuracy for the detection of MCI (AUC = .89, p < .001) and AD (AUC = .99, p < .001), and for the differentiation between the clinical groups (AUC = .76, p < .001). We provide optimal cut-offs for the identification of MCI and AD and for their differentiation. We also found that, in general, higher education predicted higher IFS scores (no associations with age and depressive/anxious symptoms were observed). Altogether, these findings indicate that evaluating executive functions with the IFS can be valuable for the identification of MCI, a high-risk group for dementia, and for differentiating this condition from healthy aging and AD.

Trait Impulsivity in Alcohol-naïve Offspring at High Risk for Alcoholism

BACKGROUND

Impulsivity is considered to be a vulnerability marker for substance use disorders, including alcoholism, in offspring with familial alcoholism. However, it is not adequately explored whether different age groups offspring at high risk for alcoholism differ in their impulsivity. The present study examined trait impulsivity in offspring at high risk for alcoholism, and further examined impulsivity by categorizing these offspring into different age groups. The study also examined the association between impulsivity and age, and the association of executive functions with age and education.

MATERIALS AND METHODS

Sample consisted of alcohol-naïve offspring at high (n = 34) and low (n = 34) risk for alcoholism. Participants were matched on age (±1 year), education (±1 year), and gender. The measures included were: Mini-international neuropsychiatric interview, family interview for genetic studies, sociodemographic data sheet, Annett's handedness questionnaire, Barratt's Impulsiveness Scale-version 11, and tests assessing executive functions.

RESULTS

Offspring at high risk for alcoholism demonstrated significantly high impulsivity. Furthermore, offspring at high risk were categorized into three subgroups with age. Results showed no significant difference between the subgroups with respect to impulsivity. Correlation analysis revealed no significant association between impulsivity and age. However, executive functions (concept formation, working memory, and safe decision-making) showed significant positive association, while perseveration and risky decision-making showed a negative association with age and education in both the groups.

CONCLUSION

The present study demonstrates high impulsivity trait in offspring at high risk for alcoholism. The high impulsivity could pose a risk for addiction and may require preventive intervention.

Effects of aging on memory strategies: a validation of the Portuguese version of the Test of Memory Strategies

OBJECTIVE

Previous literature has shown that executive functions (EF) are related to performance in memory tasks. The fact that there are no psychometric tests that evaluate these two constructs simultaneously led a group of researchers to develop the Test of Memory Strategies (TSM). Given the potential importance of this instrument for neuropsychological evaluation, in this study, we aimed to evaluate the psychometric properties of the TMS in Portuguese sample. We also examined the effect of aging by exploring profiles of performance on the TMS, comparing young and elderly healthy subjects.

METHOD

Total of 135 healthy participants were submitted to a neuropsychological assessment and were divided into four age groups: a group of young adults (25-35 years) and three groups of older individuals (aged 60-69 years, 70-79 years, and 80 or more years).

RESULTS

Findings supported the reliability of the TMS scores, based on analyses of internal consistency. As expected, factor analysis of the TMS scores revealed that the test yielded two factors, one capturing EF and the other memory. Correlations with classic neuropsychological tests supported convergent and discriminant validity of the TMS scores. The elderly groups presented more difficulties in creating and mobilizing memory strategies when compared with a younger group, after controlling for the influence of education, although both groups presented increases in performance throughout the five TMS subscales.

CONCLUSIONS

The findings suggest that the TMS is an adequate measure to assess memory and EF, simultaneously, presenting adequate psychometric properties for a Portuguese sample.

Impact of sociodemographic variables on executive functions

Executive functions (EFs) regulate human behavior and allow individuals to interact and act in the world. EFs are sensitive to sociodemographic variables such as age, which promotes their decline, and to others that can exert a neuroprotective effect.

Strictly Lobar Cerebral Microbleeds Are Associated With Cognitive Impairment

Background and Purpose—

Different distributions of cerebral microbleeds (CMBs) are associated with distinct pathological mechanisms. Lobar CMBs are thought to be related to cerebral amyloid angiopathy, whereas deep or infratentorial CMBs are related to hypertensive vasculopathy. The present study aimed to evaluate the effects of CMBs and their locations on a variety of cognitive domains.

Methods—

Study subjects were selected from the community-based I-Lan Longitudinal Aging Study. We assessed cognitive domains, including verbal memory, language, visuospatial executive function, and verbal executive function. CMBs were evaluated using 3T susceptibility-weighted magnetic resonance imaging.

Results—

We studied 959 subjects (mean±SD, 62.5±8.6 years; 425 [44.3%] men). CMBs were found in 14.2% of the population. We classified subjects with CMBs into 2 different groups based on the locations of their CMBs: (1) deep or infratentorial (85 subjects, 8.8% of population) and (2) strictly lobar (49, 5.1%). Multivariate linear analysis showed that strictly lobar CMBs were significantly associated with deficits in global cognitive function (Mini-Mental State Examination) and visuospatial executive function, as determined by the copy test of the Taylor complex figure test and the clock drawing test. We adjusted our results for age, sex, years of education, cardiovascular risk factors, and other markers of cerebral small vessel disease, lacunes, and white matter hyperintensity. Deep or infratentorial CMBs were not associated with changes in cognitive function in our population.

Conclusions—

Strictly lobar, but not deep or infratentorial, CMBs are associated with changes in cognitive function, especially in visuospatial executive functions. Cerebral amyloid angiopathy may be the underlying pathology associated with CMB-related cognitive impairment.