School Achievement in Early Adolescence Is Associated With Students' Self-Perceived Executive Functions

The primary aim of this study was to investigate the relation between self-perceived executive functions (EFs) and the school achievement of young adolescents (aged 10–12 years), while controlling for parental education and sex. We specifically focused on executive aspects of daily life behavior and the higher-order EFs, as measured with self-report, rather than on the more basic EFs which have been the primary focus of prior investigations. In two independent samples of sixth graders (N > 200 each), students evaluated their EFs on a self-report questionnaire, the Amsterdam Executive Functioning Inventory. School achievement in the domains of mathematics and reading comprehension were evaluated with nationally used, norm-based achievement tests. Results revealed that the self-perceived EFs of young adolescents were significantly correlated with their school achievement in both study samples. School achievement was also correlated with the level of parental education, but the factor sex did not have such influence. In study 1, self-perceived EFs explained additional variance in school achievement, while controlling for parental education and sex. In study 2, this was only the case for the most robust measure of school achievement, i.e., the end-of-primary-school final achievement test. Furthermore, besides the relation with achievement tests, we also found a relation between self-perceived EFs and teacher ratings behavioral problems in the classroom. Together, our findings imply that young students can properly reflect on the effectiveness and appropriateness of their EFs in a way that is relevant to their academic achievement and classroom behavior. The findings underscore the importance of considering the development of EFs and parental education in the evaluation of academic achievements in early adolescence.

Sex differences in self-regulation in early, middle and late adolescence: A large-scale cross-sectional study

This large-scale cross-sectional study had the aim to investigate whether adolescent males and females differ in self-perceived self-regulation. The large sample size allowed us to investigate sex differences in three age-groups of young (n = 161), middle (n = 133) and late (n = 159) adolescents. Self-regulation was evaluated with a self-report questionnaire, the Amsterdam Executive Functioning Inventory (AEFI). This questionnaire gives a proxi for three executive functions that are important for proper self-regulation: (1) self-control & self-monitoring, (2) attention, and (3) planning & initiative taking. Results revealed clear sex differences in the self-regulation as perceived by mid-adolescents (i.e., 13-16 years). In this age period, females evaluated their attention higher than males, and they reported higher levels of self-control & self-monitoring. Our findings offer important new insights with respect to the decision making, academic achievements and behaviour of 13-16-year olds. Self-regulation is known to have a central role in academic achievement and in behavioural organisation. The sex differences in self-regulation in mid-adolescence may therefore explain part of the difference which males and females in this age-group exhibit in academic achievements and behavioural organisations. The results imply that self-regulation may be a relevant intervention target: rather than focussing on changing behaviour, interventions may focus more on self-insights and thereby changing the adolescent's perceptions about their behaviour. Increased self-insight may have the potency to actually change behaviour, which might be an interesting target for future investigation.

Eating the right amount of fish: inverted U-shape association between fish consumption and cognitive performance and academic achievement in Dutch adolescents

Fish consumption has shown its benefits for cognitive functioning in the elderly or children with disorders (e.g., autism, ADHD), but has rarely been investigated in relation to cognitive performance and school performance of healthy adolescents. We executed an observational study in 700 Dutch high school students aged 12-18 years. Fish consumption data, end term grades, scores on the Amsterdam Vocabulary Test, and scores on the Youth Self-Report were collected. Results revealed that 13.6% of the Dutch adolescents never ate fish, 6.4% met national guidelines, 16.9% reached half of the norm, and 63.1% did eat fish but too little to meet at least half of the norm. Analysis of variance, controlled for relevant covariates, showed significant differences between the four fish consumption groups in vocabulary (p=.05). A trend for significance was found for end term grades (p=.07). Contrast analyses demonstrated significant quadratic associations between fish consumption and vocabulary (p=.01) and end term grades (p=.01). Thus higher fish intake was associated with more advanced vocabulary and higher end term grades. However, eating more fish than the described norm seemed no longer beneficial.

MTHFR polymorphisms and cognitive ageing in the ninth decade: the Lothian Birth Cohort 1921

Low blood levels of B vitamins have been implicated in age-associated cognitive impairment. The present study investigated the association between genetic variation in folate metabolism and age-related cognitive decline in the ninth decade of life. Both the 677C>T (rs1801133) polymorphism and the scarcely studied 1298A>C (rs1801131) polymorphism of the MTHFR gene were assessed in relation to cognitive change over 8 years in older community-dwelling individuals. MTHFR genotype was determined in 476 participants of the Lothian Birth Cohort 1921, whose intelligence was measured in childhood in the Scottish Mental Survey of 1932. Cognitive performance on the domains of verbal memory, reasoning and verbal fluency was assessed at mean age of 79 (n = 476) and again at mean ages of 83 (n = 275) and 87 (n = 180). Using linear mixed models, the MTHFR 677C>T and 1298A>C variants were not associated with the rate of cognitive change between 79 and 87 years, neither in the total sample, nor in a subsample of individuals with erythrocyte folate levels below the median. APOE E4 allele carrier status did not interact with MTHFR genotype in affecting change in cognitive performance over 8 years. No significant combined effect of the two polymorphisms was found. In conclusion, MTHFR 677C>T and 1298A>C polymorphisms were not associated with individual change in cognitive functioning in the ninth decade of life. Although polymorphisms in the MTHFR gene may cause disturbances in folate metabolism, they do not appear to be accompanied by changes in cognitive functioning in old age.

Acute tryptophan depletion selectively attenuates cardiac slowing in an Eriksen flanker task

In the present study, the effects of transiently lowering central serotonin levels by means of acute tryptophan depletion on measures of cognitive flexibility were examined. Flexible behaviour was measured in an Eriksen flanker task, and cardiac and electro-cortical responses to errors and congruent and incongruent stimuli were measured. The depletion was successful in lowering tryptophan levels and, as expected, it did not affect subjective mood. Depletion did not affect performance and electro-cortical measures and selectively affected cardiac measures. Depletion attenuated cardiac slowing to incongruent flanker stimuli but did not affect cardiac responses to congruent stimuli and errors. The selective effect on cardiac responses as compared to performance and electro-cortical measures was in accordance with earlier findings, as well as the attenuation of cardiac slowing. The selective effect on the cardiac response to incongruent stimuli was unexpected. Detailed analyses showed a close connection to the earlier reported attenuation of the cardiac response to negative feedback, and the effect is explained in terms of reduced anticipation of the feedback stimulus due to enhanced punishment prediction.

Affective symptoms as predictors of Alzheimer's disease in subjects with mild cognitive impairment: a 10-year follow-up study

BACKGROUND

Affective symptoms are common in subjects with mild cognitive impairment (MCI), but there is disagreement whether these symptoms are predictive for Alzheimer's disease (AD). We investigated the predictive accuracy of affective symptoms for AD during a follow-up study in subjects with MCI, and whether the predictive accuracy was modified by age, the presence of amnestic MCI or the length of follow-up.

METHOD

Newly referred subjects (n=263) with MCI older than 55 years were selected from a memory clinic and followed up after 2, 5 and 10 years. Predictors investigated were: symptoms of depression, anxiety, apathy and sleeping problems.

RESULTS

Affective symptoms were present in 50-70% of the subjects. The average follow-up period was 5.4 years and 79 subjects (29%) developed AD. Sleeping problems were associated with a decreased risk for AD [odds ratio (OR) 0.35, p<0.001]. Symptoms of depression (OR 0.61, p=0.059) and anxiety (OR 0.58, p=0.051) showed a trend in the same direction. The OR of apathy for AD was 0.67 (p=0.14). Depression was associated with a decreased risk for AD only in subjects without amnestic MCI, but not in subjects with amnestic MCI. Moreover, anxiety was related to the risk for AD differently between subjects diagnosed with AD at the 5-year follow-up (OR 0.23) and subjects diagnosed with AD at the 10-year follow-up (OR 1.7).

CONCLUSIONS

Affective symptoms are associated with a decreased risk for AD. The risk may be dependent on MCI subtype or length of follow-up, but it does not depend on age.

Fish consumption, not fatty acid status, is related to quality of life in a healthy population

Depressive symptoms in the community have a considerable impact on quality of life. Although long-chain polyunsaturated fatty acids (LCPUFA) have frequently been implicated in depressed mood, their relationship with quality of life has scarcely been investigated. This study examined the cross-sectional associations between fish consumption and plasma phospholipid LCPUFA status on the one hand, and quality of life, as measured by the Short Form 36 questionnaire, on the other in a population-based sample. The mental health component of quality of life was not associated with LCPUFA status or fish consumption. Fish consumption showed a positive association with physical well-being, which remained significant after correction for LCPUFA status, suggesting that the relationship between fish consumption and physical well-being is independent of the LCPUFA content of fish. These findings indicate that fish consumption may serve as a proxy for a healthy lifestyle or a favorable nutritional status, which is reflected in better quality of life.

Developmental changes in semantic verbal fluency: analyses of word productivity as a function of time, clustering, and switching

We investigated age-related improvement in semantic category verbal fluency (VF) in 309 Dutch schoolchildren attending first to ninth grade. Quantitative analyses of number of correct responses as a function of time as well as qualitative analyses of clustering and switching were conducted. Overall, Dutch VF task performance, i.e., number of correct responses over 60 seconds, was not established before mid-adolescence. This is in line with previously published studies, using VF number of correct responses over 60 seconds as the main outcome measure and examining VF task performance across other cultures and languages (e.g., Italian, French, Hebrew). Next, mean cluster size, a measure of lexico-semantic knowledge, was not established until at least grade 3. In contrast, performance on the VF outcome measures "number of switches/clusters" was established at least 4 years later. Qualitative and quantitative Design Fluency (DF) outcome measures support the notion that the numbers of switches/clusters are valid measures of higher order cognitive functions, such as strategy use and cognitive flexibility. In line of this, VF number of correct responses during 16-60 seconds, a measure of controlled information processing, is established at least 2 years later (i.e., grades 7-8) than number of correct responses during the first 15 seconds time slide, a measure of automatic processing. Finally, environment, i.e., the level of parental education, primarily affected automatic and lexico-semantic knowledge. No effects of sex on VF performance were found. These data suggest that the alternative scoring methods of VF tasks can be used to acquire knowledge on development of lower and higher order cognitive functions in healthy children and the influence of the environment on it.

Diabetes mellitus type II as a risk factor for depression: a lower than expected risk in a general practice setting

The aim of the present study was to determine whether a diagnosis of diabetes mellitus (DM) in a primary setting is associated with an increased risk of subsequent depression. A retrospective cohort design was used based on the Registration Network Family Practice (RNH) database. Patients diagnosed with diabetes mellitus at or after the age of 40 and who were diagnosed between 01-01-1980 and 01-01-2007 (N = 6,140), were compared with age-matched controls from a reference group (N = 18,416) without a history of diabetes. Both groups were followed for an emerging first diagnosis of depression (and/or depressive feelings) until January 1, 2008. 2.0% of the people diagnosed with diabetes mellitus developed a depressive disorder, compared to 1.6% of the reference group. After statistical correction for confounding factors diabetes mellitus was associated with an increased risk of developing subsequent depression (HR 1.26; 95% CI: 1.12–1.42) and/or depressive feelings (HR 1.33; 95% CI: 1.18–1.46). After statistical adjustment practice identification code, age and depression preceding diabetes, were significantly related to a diagnosis of depression. Patients with diabetes mellitus are more likely to develop subsequent depression than persons without a history of diabetes. Results from this large longitudinal study based on a general practice population indicate that this association is weaker than previously found in cross-sectional research using self-report surveys. Several explanations for this dissimilarity are discussed.

The posterior parahippocampal gyrus is preferentially affected in age-related memory decline

Atrophy in the medial temporal lobe is generally considered to be highly associated with age-related memory decline. Volume loss in the hippocampus and entorhinal cortex has extensively been investigated, but the posterior parts of the parahippocampal gyrus have received little attention. The present MRI study investigated whether volume differences in medial temporal lobe areas are differentially related to age-related memory decline. Thirty-nine subjects from a longitudinal study on cognitive aging (the Maastricht Aging Study) have been examined: 20 participants (mean age=67 years, range 52-80) with memory decline over a period of 12 years were matched to 19 participants without memory decline. Manual tracing was performed on 3T MR images to measure the volumes of the anterior, middle and posterior parts of the hippocampus and parahippocampal gyrus. A robust group difference and a significant association with memory decline were observed only in the posterior part of the parahippocampal gyrus. Our results may suggest that the posterior parahippocampal gyrus plays a key role in age-related memory decline.

Multiple indicators of age-related differences in cerebral white matter and the modifying effects of hypertension

We investigated differences associated with age and hypertension, a common risk factor for vascular disease, in three aspects of white matter integrity--gross regional volumes of the white matter, volume of the white matter hyperintensities (WMH) and diffusion properties. We acquired MRI scans on 93 adult volunteers (age 50-77 years; 36 with diagnosis of hypertension or elevated blood pressure), and obtained all measures in seven brain regions: frontal, temporal, parietal and occipital white matter, and the genu, body and splenium of the corpus callosum. The results demonstrated robust age-related differences in diffusion-based indices of cerebral white matter integrity and age-related increase in the WMH volume, but no age differences in the gross regional volumes of the white matter. Hypertension was associated with decline in fractional anisotropy, and exacerbated age differences in fractional anisotropy more than those in the volume of WMH. These findings indicate that of all examined measures, diffusion-based indices of white matter integrity may be the most sensitive indicators of global and regional declines and vascular damage in the aging brain.

Does cognitive function in older adults with hearing impairment improve by hearing aid use?

In the present study, the effects of hearing aid use by hearing-impaired older individuals on different aspects of cognitive function, such as memory, attention, executive functioning, and processing speed, were investigated. Fifty-six participants (mean age = 72.5) who were fitted with hearing aids were compared with 46 control participants (mean age = 74.5) with an equivalent hearing impairment, but who were not fitted with a hearing aid. After a dual baseline measurement and fitting of the hearing aids, all participants were assessed again with neurocognitive tests after 12 months. While the participants with hearing aids had improved aided hearing thresholds, they did not demonstrate an improved performance on the cognitive tests compared to the controls. Thus improved hearing did not improve cognitive functioning. These findings may suggest that hearing aid use only restores impairments at the level of the sensory organ, but does not affect the central nervous system and, as a consequence, cognitive functioning.

Cognition as predictor of current and follow-up depressive symptoms in the general population

OBJECTIVE

Previous studies have reported an association between depression and poor cognitive functioning. Unknown is to what degree such associations are merely state-related or reflect an enduring depression vulnerability. This study examined whether cognitive deficits predict current and/or follow-up (sub)clinical depressive symptoms in the general population.

METHOD

A population-based sample of 569 female twins and 43 of their sisters completed a neuropsychological battery. Cross-sectional and prospective associations between depressive symptoms measured at the subclinical [Symptom Checklist-90 (SCL-90)] and clinical level (Structured Clinical Interview for DSM-IV disorders) and neuropsychological factors (episodic memory and information processing speed) were examined.

RESULTS

Structured Clinical Interview for DSM-IV disorders baseline depressive symptoms were significantly associated with information processing speed but not with episodic memory. Episodic memory was significantly associated with follow-up SCL-90 depressive symptoms.

CONCLUSION

Being depressed is accompanied by slower information processing. Poor memory functioning may be a predictor for the onset of subclinical depressive symptoms.

Predictive value of mild cognitive impairment for dementia. The influence of case definition and age

BACKGROUND/AIMS

In population studies, different mild cognitive impairment (MCI) definitions have been used to predict dementia at a later stage. This study compared predictive values of different MCI definitions for dementia, and the effect of age on the predictive values was investigated.

METHODS

This study was conducted as part of an ongoing longitudinal study into the determinants of cognitive aging, the Maastricht Aging Study.

RESULTS

MCI best predicted dementia when multiple cognitive domains were considered and subjective complaints were not (sensitivity: 0.66, specificity: 0.78). Age had a strong influence on the sensitivity of MCI for dementia (age 60-70 years: sensitivity = 0.56; age 70-85 years: sensitivity = 0.70).

CONCLUSION

The inclusion of multiple cognitive domains and participants aged 70 years and older leads to the best prediction of dementia, regardless of subjective complaints.

[Category fluency (animals, professions) in normal cognitive ageing and dementia]

Regression-based normative data for commonly used semantic verbal fluency test (VFT) scores were derived from data of the Maastricht Aging Study (N=1,825; age range 24-81). Animal naming, profession naming, and the summed score (animal + profession naming) were shown to be profoundly affected by demographical variables, especially age and educational level. The clinical utility of the newly established regression-based VFT norms was evaluated in a large sample of psychogeriatric patients (N=1,063, of which n=890 met the criteria for Alzheimer's or vascular dementia). Results showed that the animal naming VFT score was the most sensitive measure to distinguish normal aging from dementia (when the specificities of the various VFT measures were equated). Fifty patients were found to commit stuck-in-set perseverations, i.e. they generated animal names during test administration of the profession naming VFT. The prevalence of stuck-in-set perseveration was 11.3% in Parkinson dementia and frontal variant frontotemporal dementia, versus 4.6% and 5.3% in dementia of the Alzheimer type and vascular dementia, respectively. Bivariate analyses revealed that people who committed stuck-in-set perseverations were more deficient on a measure of free recall and on several tests of executive control, such as the Expanded Mental Control Test, the Behavioral Dyscontrol Scale and the Alternating Graphical Sequences Test as a measure of response inhibition. Using multivariate logistic regression analysis, only the Alternating Graphical Sequences Test retained an independent effect in the association with stuck-in-set perseveration.

The association between APOE genotype and memory dysfunction in subjects with mild cognitive impairment is related to age and Alzheimer pathology

BACKGROUND

Memory problems are a main feature of mild cognitive impairment (MCI) and may be related to the apolipoprotein E (APOE) epsilon4 allele. We investigated whether the effect of the APOE genotype on memory in subjects with MCI was dependent on age and underlying Alzheimer disease (AD) pathology.

METHODS

Subjects with MCI (n = 180) were selected from a memory clinic setting. Subjects with at least one APOE epsilon4 allele (n = 83) were compared to non-carriers on several memory measures. Subjects were reassessed 5-10 years later in order to identify those who developed AD.

RESULTS

In the middle-aged subgroup, the APOE epsilon4 allele was most strongly related to decreased subjective organization and in the old subgroup to a decreased delayed recall. After excluding subjects with incipient AD (n = 33), results remained similar in the middle-aged subgroup, but in the old subgroup the APOE genotype was no longer associated with memory dysfunction.

CONCLUSION

The presence of the APOE epsilon4 allele is associated with impaired memory functioning in both middle-aged and old subjects with MCI, although the memory function affected varies with age. Its effect on memory function may be dependent on underlying AD pathology in elderly subjects, but not in middle-aged subjects.

Development of screening guidelines and clinical criteria for predementia Alzheimer's disease. The DESCRIPA Study

BACKGROUND

There is an urgent need to identify subjects with Alzheimer's disease (AD) in the predementia phase, but validated diagnostic approaches are currently lacking. In this paper, we present the background, design and methods of a study, which aims to develop clinical criteria for predementia AD. We also present baseline characteristics of the subjects included. The study was part of the multicentre DESCRIPA project, which is being conducted within the network of the European Alzheimer's Disease Consortium.

METHODS

Clinical criteria will be based on a prospective cohort study of non-demented subjects older than 55 years and referred to a memory clinic. At baseline, a number of markers and risk factors for AD were collected, including demographic variables, measures of performance in activities of daily living, cognitive, neuroimaging and genetic markers, and serum and cerebrospinal fluid markers. Subjects will be reassessed annually for 2-3 years, and we will evaluate which combination of variables best predicts AD-type dementia at follow-up.

RESULTS

Between 2003 and 2005, 881 subjects were included from 20 memory clinics. Subjects were on average 70.3 years old, and had 10.4 years of education. The average score on the Mini-Mental State Examination was 27.4.

Transfer effects of a cognitive strategy training for stroke patients with apraxia

The objective of this study was to evaluate transfer effects of cognitive strategy training for stroke patients with apraxia. During 8 weeks, 29 apraxic patients received cognitive strategy training to teach them how to perform activities of daily living (ADL) as independently as possible. ADL functioning was assessed at the rehabilitation centre at baseline and after 8 weeks of training. In addition, assessment took place at the patients' own homes after 8 weeks of training and 5 months after the start of the training. The performance of both trained and nontrained tasks was observed. Patients performed trained tasks and nontrained tasks at the same level of independency at the rehabilitation centre as well as at home, indicating transfer of training effects. These effects turned out to be stable over time.

Cognitive functioning in healthy older adults aged 64-81: a cohort study into the effects of age, sex, and education

The objective of this study was to determine a possible differential effect of age, education, and sex on cognitive speed, verbal memory, executive functioning, and verbal fluency in healthy older adults. A group of 578 healthy participants in the age range of 64-81 was recruited from a large population study of healthy adults (Maastricht Aging Study). Even in healthy individuals in this restricted age range, there is a clear, age-related decrease in performance on executive functioning, verbal fluency, verbal memory, and cognitive speed tasks. The capacity to inhibit information is affected most. Education had a substantial effect on cognitive functioning: participants with a middle or high level of education performed better on cognitive tests than did participants with a low level of education. Women performed better than men on verbal memory tasks. Therefore, education and sex must be taken into account when examining an older individual's cognitive performance.

[Development of memory clinics in The Netherlands]

AIM

Memory Clinics (MC's) are multidisciplinary teams involved with early diagnosis and treatment of people with dementia. In order to attain more insight into the development of this kind of services in The Netherlands, we compared the data of two inventories, one of 1998 and the other of 2004.

RESULTS

The number of MC's increased from 12 to 40. The number of referrals per service has also increased. Dementia was the most important syndromal diagnosis. The focus is less exclusively on academic centres. An growing number of MC's has structural collaborations with local service providers for mental health. Differences among MC's exist with regard to the number of referrals per week, the intensity and duration of the diagnostic procedures and the proportion of people without dementia. There is much interest among MC's to participate in a national network for harmonisation and quality control.

CONCLUSION

MC's are an increasing part of standard care for people with early dementia and other cognitive disorders.

Subclinical psychotic experiences and cognitive functioning as a bivariate phenotype for genetic studies in the general population

OBJECTIVE

Cognitive deficits may be vulnerability markers for the development of schizophrenia. This study examined whether cognitive deficits are related to specific dimensions of subclinical psychotic experiences and whether associations between these variables are caused by additive genetic, common environmental and/or individual-specific environmental factors.

METHOD

A general population sample of 298 female twin pairs completed the Community Assessment of Psychic Experiences and a neuropsychological test battery. Associations between subclinical positive and negative psychotic dimensions and neuropsychological factors (episodic memory and information processing speed) were examined. Univariate correlation and structural equation analyses were performed to explore the role of genetic and environmental factors in the phenotypes separately. Bivariate correlation and structural equation analyses were applied to examine the causes of association.

RESULTS

There were significant correlations between information processing speed and both the positive (r=.11; p<.05) and the negative dimension (r=.10; p<.05). For the negative dimension and for speed of processing, the data suggested a model that included genetic factors. The observed phenotypic correlation between the negative dimension and information processing speed could be solely explained in terms of additive genetic factors. Although the comparison of the correlations for MZ and DZ pairs did not give a clear indication as to the underlying causes of the association, structural equation modelling suggested that the observed phenotypic correlation between the negative dimension and information processing speed could be solely explained in terms of additive genetic factors.

CONCLUSION

Negative symptoms and information processing speed are associated at the subclinical level and this association appears to be influenced by genetic factors exclusively. Bivariate psychosis phenotypes may represent suitable candidates for molecular genetic studies in the general population.

Exploratory study into the relation between plasma phospholipid fatty acid status and cognitive performance

Previous research found a negative association between DHA status and selective attention in pregnant women. Goal of the present exploratory study is to investigate the potential relationship between essential fatty acid status and cognitive performance in a healthy non-pregnant population. Cognitive performance of 54 non-pregnant women was determined at baseline, 3, 15, and 22 weeks later with an objective neurocognitive test battery covering different brain domains. Plasma phospholipid fatty acid status was determined at baseline and at 22 weeks. The fatty acids of primary interest (arachidonic acid, adrenic acid, Osbond acid, eicosapentaenoic acid, and docosahexaenoic acid) were no significant predictors of cognitive performance at baseline or 22 weeks later. However, they attributed significantly (26.3%) to the amount of explained variance of the learning effect on the Stroop task, measuring general speed of information processing. Higher docosahexaenoic acid levels were associated with a slower learning curve. For arachidonic acid the opposite was found. In conclusion, this study provides a preliminary indication that a higher DHA status might be associated with slower learning curves. However, additional studies are necessary.

Acute tryptophan depletion improves performance and modulates the BOLD response during a Stroop task in healthy females

To gain more insight into the effect of low brain serotonin (5-HT) on brain activation related to conflict, the present study examined the effect of acute tryptophan depletion (ATD) on performance and the blood oxygen level dependent (BOLD) response during a combined cognitive and emotional Stroop task. Fifteen healthy female volunteers were tested during a placebo and tryptophan depletion session in an event-related fMRI design. ATD improved performance during Stroop interference. Two effects of ATD on the BOLD response were found. Firstly, ATD increased the BOLD response in the anterior cingulate cortex (ACC) (BA 32) when incongruent color words were compared with congruent color words in the first Stroop block the participants performed. Secondly, ATD increased the BOLD response in the left precuneus (BA 31) and cuneus (BA 18) during congruent color words. ATD did not affect the BOLD response accompanying emotional stimuli. However, we showed that ATD increased the interference of negative words on color naming. This finding was explained in terms of an emotional processing bias in favor of negative words, which leads to stronger interference of these words. In line with previous studies, the present study showed that a temporary reduction of 5-HT improved Stroop performance and changed the underlying brain activation pattern in healthy female participants. Moreover, we replicated our previous finding that ATD modulated the BOLD response in the dorsomedial prefrontal cortex during tasks that require cognitive control.

Semantic category fluency versus initial letter fluency over 60 seconds as a measure of automatic and controlled processing in healthy school-aged children

Verbal fluency was operationalized as the number of words produced in a restricted category (i.e., semantic category [SCF] and words beginning with a given letter [ILF]) in 60 seconds. Word production in the first 15 seconds of either type of fluency task was defined as a measure of automatic information processing, whereas word production in the remaining 45 seconds (in 15-second periods) was taken as a measure of controlled information processing. Data revealed that over 60 seconds healthy children aged 8.4-9.7 years (n = 91) produced significantly more words and less incorrect responses on the SCF task than on the ILF task. Although word production was a function of both type of task and time, it was highest in the initial time slice of either type of fluency and decreased as time on task increased. Finally, no sex differences were found for any measure of performance on either type of fluency task. In contrast, the level of occupational achievement of the caregiver (LOA) appeared to be a determinant of the child's performance on either type of fluency task, indicating that LOA affects higher-order processes, such as the automation of newly learned verbal skills and effortful processing.

Differences in cognitive performance during pregnancy and early motherhood

BACKGROUND

Pregnancy has often been associated with cognitive deficits, but results are equivocal and little is known about how these deficits progress with time.

METHOD

In the present study, the cognitive performance of 57 pregnant women was compared with that of 50 non-pregnant women matched for age and education, using a well-validated neurocognitive test battery at weeks 14, 17, 29, and 36 of pregnancy, and 32 weeks postpartum in the pregnant group and at comparable times in the non-pregnant group.

RESULTS

Memory encoding and retrieval, as assessed with a word learning task, were significantly lower in the pregnant group than in the control group. This difference was still present at 32 weeks after delivery. The two groups did not differ in complex speed of information processing at any of the test moments; however, general speed of information processing was significantly compromised during early motherhood (week 32 postpartum).

CONCLUSION

Thus, memory performance is poorer during pregnancy and early motherhood, and general speed of information processing is slower during early motherhood.

Ambulatory blood pressure, asymptomatic cerebrovascular damage and cognitive function in essential hypertension

Prolonged exposure to elevated blood pressure (BP) can lead to both structural (white matter lesions (WML) or infarctions) and functional changes in the brain. We studied in previously diagnosed essential hypertensive individuals if diurnal BP variation and ambulatory BP (ABP) profile (daytime, night time and 24-h BP averages) were related to evidence of WML, the presence of 'silent' infarcts, and cognitive performance. A group of 86 patients (mean age 57.4+/-10 years, range 40-80) were first screened for hypertension-related organ damage and underwent 24-h ABP monitoring, magnetic resonance imaging (MRI) of the brain, and a comprehensive neurocognitive assessment. Age and ABP profile were related to more periventricular, but not subcortical, WML and to presence of lacunar infarctions on MRI. After correction for demographical group differences, no association was found between night time dipping of BP on the one hand and both WML load and cognitive parameters (verbal memory, sensorimotor speed, cognitive flexibility) on the other. The presence of lacunar infarctions, however, predicted lower performance on verbal memory. Furthermore, daytime and 24-h pulse pressure averages were associated with pWML, whereas systolic BP and mean arterial pressure (MAP) for daytime, night-time and 24-h periods were higher in patients with lacunar infarctions. Notwithstanding the large variability of WML in this sample, the evidence of a connection between diurnal BP variation and early target organ damage in the brain was not convincing. However, the ABP profile may be predictive of cerebral lesion type.

Prevalence of primitive reflexes and the relationship with cognitive change in healthy adults

OBJECTIVES

Primitive reflexes (PR) generally disappear early in life but may reappear later, in which case they are often associated with chronic neurological conditions, such as dementia or Parkinson's disease. Studies have shown that the presence of PRs may be indicative of both the severity and rate of progression of these diseases and may be the result of disinhibition of cortical networks. The association between PRs and cognitive function in usual ageing is unclear. We investigated whether the occurrence, amplitude, and persistence of four nociceptive (glabbelar tap, palmomental, pollicomental, and snout reflexes), three prehensile reflexes (suck, palmar grasp, and rooting), and two other reflexes (mouth open finger-spread and nuchocephalic reflexes) were related to performance in specific cognitive domains in normal ageing individuals.

METHODS

Four-hundred and seventy normal aging participants (25-82 years) in the Maastricht Aging Study (MAAS), were included in the study. They were neurologically and cognitively screened at baseline and were retested after 3 (only individuals aged 50 years and older at baseline) and 6 years.

RESULTS

The prevalence of most PRs increased with age: 47% of men aged 25-45 years had at least one PR, compared with 73% of men aged 65-85 year (p = 0.002). In women these percentages were 51 and 75, respectively (p=0.008). The prevalence, amplitude, and persistence of PRs were unrelated to cognition at baseline or at the 3- or 6-year follow-up.

CONCLUSIONS

The prevalence of particularly nociceptive reflexes rises substantially with increasing age in normal individuals. However, the presence of PRs cannot be considered to be a marker of cognitive decline in normal aging individuals.

Increase in periventricular white matter hyperintensities parallels decline in mental processing speed in a non-demented elderly population

OBJECTIVE

To investigate the influence of deep white matter hyperintensities (DWMH) and periventricular white matter hyperintensities (PVWMH) on progression of cognitive decline in non-demented elderly people.

METHODS

All data come from the nested MRI sub-study of the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). We performed a 3 year follow up study on 554 subjects of the PROSPER study using both repeated magnetic resonance imaging and cognitive testing. Cognitive decline and its dependency on WMH severity was assessed using linear regression models adjusted for sex, age, education, treatment group, and test version when applicable.

RESULTS

We found that the volume of PVWMH at baseline was longitudinally associated with reduced mental processing speed (p = 0.0075). In addition, we found that the progression in PVWMH volume paralleled the decline in mental processing speed (p = 0.024). In contrast, neither presence nor progression of DWMH was associated with change in performance on any of the cognitive tests.

CONCLUSION

PVWMH should not be considered benign but probably underlie impairment in cognitive processing speed.

Is peri-operative cortisol secretion related to post-operative cognitive dysfunction?

BACKGROUND

The pattern of cortisol secretion is influenced by surgery. As cortisol can adversely affect neuronal function, this may be an important factor in the development of post-operative cognitive dysfunction (POCD). We hypothesized that the incidence of POCD would be related to changes in cortisol level.

METHODS

We studied 187 patients aged over 60 years undergoing major non-cardiac surgery with general or regional anaesthesia. Saliva cortisol levels were measured pre-operatively and at 1 day, 7 days and 3 months post-operatively in the morning (08.00 h) and in the afternoon (16.00 h) using salivettes. Cognitive function was assessed pre-operatively, on day 7 and at 3 months using four neuropsychological tests. POCD was defined as a combined Z score of greater than 1.96.

RESULTS

After surgery, salivary cortisol concentrations increased significantly. POCD was detected in 18.8% of subjects at 1 week and in 15.2% after 3 months. The pre-operative ratios between the morning and afternoon cortisol concentrations (am/pm ratios) were 2.8 and 2.7 in patients with POCD at 1 week vs. those without POCD at 1 week, respectively. The am/pm ratios decreased significantly post-operatively to 1.9 and 1.6 at 1 week, respectively (P = 0.02 for both). In an analysis considering all am/pm ratios, it was found that the persistent flattening in am/pm ratio was significantly related to POCD at 1 week.

CONCLUSION

The pattern of diurnal variation in cortisol level was significantly related to POCD. Thus, circadian rhythm disturbance or metabolic endocrine stress could be an important mechanism in the development of cognitive dysfunction after major surgery.

Generalized atherosclerosis, cognitive decline, and depressive symptoms in old age

BACKGROUND

Atherosclerosis may be linked to cognitive decline and depression in old age.

METHODS

The Leiden 85-Plus Study is a prospective population-based study of 599 subjects from age 85 onward. The generalized atherosclerotic burden was rated by the number of cardiovascular pathologies at baseline, as assessed by history taking from treating physicians and EKG. Cardiovascular pathologies included myocardial infarction, angina pectoris or myocardial ischemia, claudicatio intermittens, and arterial surgery. Global cognitive function (Mini-Mental State Examination), attention (Stroop Test), processing speed (Letter Digit Coding Test), immediate recall memory (Word Learning Test-Immediate Recall), delayed recall memory (Word Learning Test-Delayed Recall), and depressive symptoms (15-item Geriatric Depression Scale) were assessed each year from ages 85 through 90. The prospective associations between both the generalized atherosclerosis rating and stroke with cognitive function and depressive symptoms were analyzed by linear mixed models adjusted for sex and level of education.

RESULTS

During follow-up, there was a significant cognitive decline and a significant increase of depressive symptoms. At baseline, a history of stroke was correlated with lower global cognitive function, slower processing speed, impaired immediate and delayed recall memory, and more depressive symptoms. In addition, a higher generalized atherosclerosis rating was correlated with impaired global cognitive function, lower attention, and a slower processing speed at baseline. During follow-up, a higher generalized atherosclerosis rating was associated with an accelerated decline of immediate recall memory and delayed recall memory. In contrast, there was no relation between the generalized atherosclerosis rating and depressive symptoms, either in the cross-sectional analysis or in the prospective analysis.

CONCLUSION

In the population at large, generalized atherosclerosis contributes to cognitive decline in old age but not to depression.

Positive affect and its relationship to free recall memory performance in a sample of older Dutch adults from the Maastricht Aging Study

OBJECTIVE

A Dutch translation of the Positive and Negative Affect Scale (PANAS) was used to measure Positive Affect (PA) and its relationship to episodic memory in a sample of Dutch adults between the ages of 40 to 82 years. Specifically, the role of PA was examined as a predictor of performance on a serial list learning task that included a recognition and free recall component.

METHODS

Participants were divided into two age groupings representing middle-age (40 to 64 years) and older (65 to 82 years) adults with respect to the study sample.

RESULTS

PA was not related to recognition performance in either age grouping. In the older age group, however, PA predicted free recall.

CONCLUSIONS

PA facilitated episodic memory in older adults when unsupported tasks conditions were present that placed heavy demands on processing resources.

Controlled visuomotor preparation deficits in attention-deficit/hyperactivity disorder

To the best of the authors' knowledge, there are no published reports on visuomotor preparation in attention-deficit/hyperactivity disorder (ADHD). This is unfortunate, because research suggests that ADHD is an output-related deficit, and suboptimal execution of tasks may be the result of incomplete visuomotor preparation. The authors compared 19 children with ADHD with 124 healthy and 120 pathological controls in terms of their performance (speed, speed variability, and accuracy) on the finger precuing test, a test measuring (automatic and controlled) visuomotor preparation. The data implied that children with ADHD have an impaired ability to engage in effortful, controlled visuomotor preparation activities. Fast, automatic response preparation was not affected by ADHD. In addition, children with ADHD showed more variability in overall test performance than other children. No group differences were found in response accuracy.

Effects of a novel method of acute tryptophan depletion on plasma tryptophan and cognitive performance in healthy volunteers

RATIONALE

Disorders associated with low levels of serotonin (5-HT) are characterized by mood and cognitive disturbances. Acute tryptophan depletion (ATD) is an established method for lowering 5-HT levels and an important tool to study the effects of reduced 5-HT on mood and cognition in human subjects. The traditional ATD method, i.e., administration of separate amino acids (AAs), has several disadvantages. The AA mixture is costly, unpalatable and associated with gastrointestinal discomfort.

OBJECTIVES

The University of Maastricht developed a new and inexpensive method for ATD: a natural collagen protein (CP) mixture with low tryptophan (TRP) content. The reductions in plasma TRP after taking this CP mixture were compared with the reductions achieved taking the traditional AA mixture, and effects on memory and reversal learning were studied.

METHODS

Fifteen healthy young volunteers participated in a double-blind, counterbalanced within-subject study. Reversal learning, verbal memory and pattern recognition were assessed at baseline and 3-4 h after taking the CP mixture.

RESULTS

The new ATD method significantly reduced plasma TRP by 74% and the ratio between TRP and the other large AAs (TRP/LNAA) by 82%. The placebo mixture did not change these measures. Delayed recognition reaction time on the verbal learning task was increased following ATD. No other cognitive effects were found.

CONCLUSIONS

The CP mixture was shown to be an efficient tool for lowering plasma TRP in humans. The validity of this method with regard to behavioral changes remains to be established in healthy, vulnerable and clinical populations.

Verbal memory and aspects of attentional control in children and adolescents with anxiety disorders or depressive disorders

BACKGROUND

The aim was to examine basic performance on attention and memory tasks in treatment-naive children and adolescents with anxiety disorder or depressive disorder and in healthy subjects under drug-free conditions.

METHODS

Basic neurocognitive performance on attention and verbal memory tasks was examined in children and adolescents with emotional disorders, between 6 and 17 years of age. A total of 34 children with an anxiety disorder, 31 children with a depressive disorder, and 33 healthy controls were assessed with a comprehensive neuropsychological test battery. All children were treatment-naive at the time of testing. Five different computerised attention tasks and the Rey Auditory-Verbal Learning Test were administered.

RESULTS

A significant effect of diagnosis was found for verbal memory but not for attention.

LIMITATIONS

The large age range and inclusion of different diagnoses resulted in rather inhomogeneous groups.

CONCLUSION

The present study provided evidence for an undisturbed attentional performance in both patient groups and a dissociation in memory functioning between anxious and depressed children. Memory impairment was found to be specifically associated with childhood depression.

Thyroid function, depressed mood, and cognitive performance in older individuals: the Maastricht Aging Study

The hypothesis was tested that thyroid function, as indicated by serum thyroid-stimulating hormone (TSH) level, is associated with cognitive performance in a healthy aging population. In a random sample of 120 participants recruited from the Maastricht Aging Study (MAAS), aged between 49 and 71 years, we assessed TSH level, mood state (Symptom Check List, subscale depression), and three domains of cognitive function: verbal memory, general sensorimotor speed, and complex flexibility. After correction for age, sex, and educational level, a negative association between TSH and memory function was apparent: higher levels of TSH predicted lower levels of memory performance. Exclusion of individuals with TSH levels suspect for thyroid disorder (n=2) or who were on thyroid replacement (n=3) attenuated this association. Furthermore, additional control for mood status reduced the association below the significance level. No interaction between age and TSH on cognition was found, which indicated that the TSH-memory association was independent of age group level. We conclude that the association between TSH level and memory performance was small and dependent on mood status and the presence of (possible) thyroid disease in this relatively healthy population based sample. Prospective studies are needed to address the role of thyroid function in age-related cognitive decline.

Verbal fluency over time as a measure of automatic and controlled processing in children with ADHD

The performance of ADHD children on semantic category fluency (SCF) versus initial letter fluency (ILF) tasks was examined. For each participant, word production was recorded for each 15-s time slice on each task. Performance on both fluency tasks was compared to test the hypothesis that children with ADHD are characterized by a performance deficit on the ILF task because performance on this task is less automated than performance on the SCF. Children classified with ADHD (N = 20) were compared to children with other psychopathology (N = 118) and healthy controls (N = 130). Results indicated that the groups could not be differentiated by the total number of words produced in 60 s in either fluency task. As hypothesized, a significant interaction of group by productivity over time by type of fluency task was found: ADHD children had more problems finding words in the first 15 s of the IFL than did children in the other two groups, and as compared with their performance on the SCF. Results were taken to indicate that children with ADHD symptoms show a delay in the development of automating skills for processing abstract verbal information.