Processing speed in normal aging: Effects of white matter hyperintensities and hippocampal volume loss

Changes in cognitive functioning are said to be part of normal aging. Quantitative MRI has made it possible to measure structural brain changes during aging which may underlie these decrements which include slowed information processing and memory loss. Much has been written on white matter hyperintensities (WMH), which are associated with cognitive deficits on tasks requiring processing speed and executive functioning, and hippocampal volume loss, which is associated with memory decline. Here we examine volumetric MRI measures of WMH and hippocampal volume loss together in relation to neuropsychological tests considered to be measures of executive functioning and processing speed in 81 non-demented elderly individuals, aged 75–90. Correlational analysis showed that when controlling for age, both greater WMH volume and smaller hippocampal volume were correlated with slower performances on most tests with the exception of a battery of continuous performance tests in which only WMH was correlated with slower reaction time (RT). We then performed a series of hierarchical multiple regression analyses to examine the independent contributions of greater WMH volume and reduced hippocampal volume to executive functioning and processing speed. The results showed that for the four measures requiring executive functioning and speed of processing, WMH volume and hippocampal volume combined predicted between 21.4% and 37% of the explained variance. These results suggest that WM integrity and hippocampal volume influence cognitive decline independently on tasks involving processing speed and executive function independent of age.     

Comparisons of the BRIEF parental report and neuropsychological clinical tests of executive function in Fetal Alcohol Spectrum Disorders: data from the UK national specialist clinic

Extant literature is sparse with regards to the relationship between caregiver reports and neuropsychological tests of executive functioning in Fetal Alcohol Spectrum Disorders (FASD). The goal of this paper was determining the clinical utilities of executive functioning measures used in the United Kingdom national FASD clinic. We examined relationships between outcomes on the Behavior Rating Inventory of Executive Function (BRIEF) and the Delis-Kaplan Executive Function System (D-KEFS), as part of an ongoing service evaluation. Profiles of executive functioning measures were reported in order to contribute to delineating a profile of executive dysfunction in FASD. Caregivers of 49 people with FASD completed the Parent BRIEF, and 61 people with FASD were administered the D-KEFS. Pearson’s Correlations between all 11 BRIEF scales and the 18 selected D-KEFS subscales showed little relationship. The BRIEF showed a profile of clinically significant elevations in all three Index scores and seven out of the eight Scale scores. Several D-KEFS tests showed below average executive functioning. Both executive function measures have separate clinical utility in demonstrating executive function deficits in FASD. The sample population used in this study also show a similar pattern to FASD populations internationally, suggesting a similar neuropsychological profile is seen in the United Kingdom. However, caregiver reports display little relationship to neuropsychological tests. These measures likely monitor different aspects of executive functioning in different settings. Future research should focus on identifying tests that better relate findings from clinical settings to behavior in daily life.     

Verbal ability and executive functioning development in preschoolers at head start

Research suggests that executive functioning skills may enhance the school readiness of children from disadvantaged homes. Questions remain, however, concerning both the structure and the stability of executive functioning among preschoolers. In addition, there is a lack of research addressing potential predictors of longitudinal change in executive functioning during early childhood. This study examined the structure of executive functioning from fall to spring of the preschool year using a multimethod battery of measures. Confirmatory factor analyses revealed a unidimensional model fit the data well at both time points, and tests of measurement invariance across time points indicated that children's mean latent executive functioning scores significantly improved over time. Verbal ability was a significant predictor of longitudinal change in executive functioning. Theoretical implications and directions for future research are discussed.     

Executive functioning in adolescent anorexia nervosa: Neuropsychology versus self- and parental-report

There is limited research concerning the relationship between neuropsychological assessment and self-report of executive functioning in adolescent anorexia nervosa (AN); available studies demonstrate only low to moderate correlations. Therefore, this study examines the association between neuropsychological test performance and self-report in AN. Forty adolescent inpatients with AN completed an extensive neuropsychological assessment, including set-shifting, central coherence, and questionnaires assessing executive functioning in daily life (BRIEF-SR). Their parents filled out an analog version (BRIEF-PF). Statistical analyses revealed low to medium positive and negative correlations between neuropsychological measures and BRIEF subscales. Similarly, self- and parental ratings were only slightly positively correlated, with patients scoring significantly higher than their parents on two subscales. The results support previous findings of modest correlations between self-report and performance-based testing and emphasize the importance of a multiple format assessment of executive functioning in adolescent AN.     

Brief report: Relationship between performance testing and parent report of attention and executive functioning profiles in children following perinatal arterial ischemic stroke

Children with perinatal arterial ischemic stroke (PAIS) have increased rates of attention and executive functioning (EF) weaknesses. Research in other pediatric disorders has documented poor consistency between parent report of these skills and performance-based measures. We compared these data sources in children with PAIS. Forty full-term (≥37 weeks) children ages 3–16 (median = 7.2 years; 58% male) with PAIS completed neuropsychological testing and composite scores were created for seven attention and EF domains (Processing Speed; Attention; Working Memory; Verbal Retrieval; Inhibitory Control; Flexibility/Shifting; Planning). Parents completed “real-world” functioning questionnaires (ADHD Rating Scale-IV, BRIEF). Correlational analysis were used to compare parent and performance measures. Correlations between ADHD Rating Scale-IV scores and the performance-based Attention and Inhibition composite scores were nonsignificant. Significant negative correlations were found between the BRIEF GEC and performance-based Verbal Retrieval and Processing Speed composites, but remaining GEC/composite comparisons were nonsignificant. Analyses between parent report BRIEF index scores and the corresponding performance-based domain identified one significant negative correlation between the BRIEF Working Memory Index and the Working Memory composite score. While children with PAIS demonstrate difficulties in attention and EF on both parent report and performance measures, little significance was found in comparisons of these two types of measures. There may be several explanations for this dissociation: measures assessing different aspects of the same underlying construct; performance-based measures lacking ecological validity; and parents underestimating/underreporting their child’s deficits. Thus, multiple sources of informant and performance data are necessary to make more accurate conclusions about functioning in these domains.     

Parent rating of executive function in fetal alcohol spectrum disorder: A review of the literature and new data on Aboriginal Canadian children

Aboriginal children in Canada are at high risk of fetal alcohol spectrum disorder (FASD) but there is little research on the cognitive impact of prenatal alcohol exposure (PAE) in this population. This paper reviews the literature on parent report of executive functioning in children with FASD that used the Behavior Rating Inventory of Executive Function (BRIEF). New data on the BRIEF is then reported in a sample of 52 Aboriginal Canadian children with FASD for whom a primary caregiver completed the BRIEF. The children also completed a battery of neuropsychological tests. The results reveal mean scores in the impaired range for all three BRIEF index scores and seven of the eight scales, with the greatest difficulties found on the Working Memory, Inhibit and Shift scales. The majority of the children were reported as impaired on the index scores and scales, with Working Memory being most commonly impaired scale. On the performance-based tests, Trails B and Letter Fluency are most often reported as impaired, though the prevalence of impairment is greater for parent ratings than test performance. No gender difference is noted for the parent report, but the boys had slightly slower intellectual functioning and were more perseverative than the girls on testing. The presence of psychiatric comorbidity is unrelated to either BRIEF or test scores. These findings are generally consistent with prior studies indicating that parents observe considerable executive dysfunction in children with FASD, and that children with FASD may have more difficulty with executive functions in everyday life than is detected by laboratory-based tests alone.     

Association of television violence exposure with executive functioning and white matter volume in young adult males

Prior research has indicated that self-reported violent media exposure is associated with poorer performance on some neuropsychological tests in adolescents. This study aimed to examine the relationship of executive functioning to violent television viewing in healthy young adult males and examine how brain structure is associated with media exposure measures. Sixty-five healthy adult males (ages 18–29) with minimal video game experience estimated their television viewing habits over the past year and, during the subsequent week, recorded television viewing time and characteristics in a daily media diary. Participants then completed a battery of neuropsychological laboratory tests quantifying executive functions and underwent a magnetic resonance imaging (MRI) scan. Aggregate measures of executive functioning were not associated with measures of overall television viewing (any content type) during the past week or year. However, the amount of television viewing of violent content only, as indicated by both past-year and daily diary measures, was associated with poorer scores on an aggregate score of inhibition, interference control and attention, with no relationship to a composite working memory score. In addition, violent television exposure, as measured with daily media diaries, was associated with reduced frontoparietal white matter volume. Future longitudinal work is necessary to resolve whether individuals with poor executive function and slower white matter growth are more drawn to violent programming, or if extensive media violence exposure modifies cognitive control mechanisms mediated primarily via prefrontal cortex. Impaired inhibitory mechanisms may be related to reported increases in aggression with higher media violence exposure.     

Long-term executive function deficits in children with traumatic brain injuries: assessment using the Behavior Rating Inventory of Executive Function (BRIEF).

Long-term deficits in executive functions following childhood traumatic brain injuries (TBI) were examined using the Behavior Rating Inventory of Executive Function (BRIEF). Parents completed the BRIEF approximately 5 years postinjury as part of a prospective study of children injured between the ages of 6 and 12. The children were between 10 and 19 years of age at the time of the assessment, and included 33 with severe TBI, 31 with moderate TBI, and 34 with orthopedic injuries. Parents also rated children's adaptive functioning and completed several other measures of parent and family functioning. Children were administered a neuropsychological test battery that included several measures of executive functions. The groups displayed a significant linear trend in BRIEF scores, with the largest deficits in executive functions reported in children with severe TBI. BRIEF scores were related consistently across groups to a test of working memory, but not to other neuropsychological measures. BRIEF scores also predicted children's adaptive functioning and behavioral adjustment, as well as parent psychological distress, perceived family burden, and general family functioning. The findings indicate that TBI results in long-term deficits in executive functions that are related to children's psychosocial outcomes, as well as to parent and family functioning.     

Long-Term Executive Function Deficits in Children With Traumatic Brain Injuries: Assessment Using the Behavior Rating Inventory of Executive Function (BRIEF)

Long-term deficits in executive functions following childhood traumatic brain injuries (TBI) were examined using the Behavior Rating Inventory of Executive Function (BRIEF). Parents completed the BRIEF approximately 5 years postinjury as part of a prospective study of children injured between the ages of 6 and 12. The children were between 10 and 19 years of age at the time of the assessment, and included 33 with severe TBI, 31 with moderate TBI, and 34 with orthopedic injuries. Parents also rated children's adaptive functioning and completed several other measures of parent and family functioning. Children were administered a neuropsychological test battery that included several measures of executive functions. The groups displayed a significant linear trend in BRIEF scores, with the largest deficits in executive functions reported in children with severe TBI. BRIEF scores were related consistently across groups to a test of working memory, but not to other neuropsychological measures. BRIEF scores also predicted children's adaptive functioning and behavioral adjustment, as well as parent psychological distress, perceived family burden, and general family functioning. The findings indicate that TBI results in long-term deficits in executive functions that are related to children's psychosocial outcomes, as well as to parent and family functioning.     

The association between negative and dysexecutive syndromes in schizophrenia: a cross-cultural study

This paper examined the relationship between the 'negative syndrome' (NS) and the neuropsychological 'dysexecutive syndrome' (DES) in schizophrenia. The study also examined whether any relationship that exists between the NS and the DES holds equally for British and Japanese subjects. We compared 26 Japanese with 17 British schizophrenic patients, divided into 'mild' and 'severe' NS groups, on the basis of performance on neuropsychological tests, including the 'Behavioural Assessment of Dysexecutive Syndrome' (BADS). We found that patients with severe NS showed more everyday executive deficits than those with mild NS. The severity of NS was correlated with executive competence. The association between NS and the BADS performance was closer than that between NS and other conventional executive measures. These findings were not influenced by cultural differences between Japanese and British subjects, and, hence, suggested the existence of culture-neutral neurobehavioural processes.     

Changing patterns of neuropsychological functioning in children living at high altitude above and below 4000 m: a report from the Bolivian Children Living at Altitude (BoCLA) study

The brain is highly sensitive to environmental hypoxia. Little is known, however, about the neuropsychological effects of high altitude residence in the developing brain. We recently described only minor changes in processing speed in native Bolivian children and adolescents living at approximately 3700 m. However, evidence for loss of cerebral autoregulation above this altitude (4000 m) suggests a potential threshold of hypoxia severity over which neuropsychological functioning may be compromised. We conducted physiological and neuropsychological assessments in 62 Bolivian children and adolescents living at La Paz (～3700 m) and El Alto (～4100 m) in order to address this issue. Groups were equivalent in terms of age, gender, social class, schooling, parental education and genetic admixture. Apart from percentage of hemoglobin saturated with oxygen in arterial blood (%SpO(2)), participants did not differ in their basal cardiac and cerebrovascular performance as explored by heart rate, mean arterial pressure, end-tidal carbon dioxide, and cerebral blood flow velocity at the basilar, anterior, middle and posterior cerebral arteries. A comprehensive neuropsychological assessment was administered, including tests of executive functions, attention, memory and psychomotor performance. Participants living at extreme altitude showed lower levels of performance in all executive tests (Cohen effect size = -0.91), whereas all other domains remained unaffected by altitude of residence. These results are compatible with earlier physiological evidence of a transitional zone for cerebral autoregulation at an altitude of 4000 m. We now show that above this threshold, the developing brain is apparently increasingly vulnerable to neuropsychological deficit.     

The relationship between cognitive performance and electrophysiological indices of performance monitoring

Studies of electrophysiological indices of performance monitoring, such as the error-related negativity (ERN), posterror positivity (Pe), and N2 components of the event-related potential (ERP), suggest that increased ERN and Pe amplitudes and decreased N2 amplitudes are associated with better cognitive flexibility and cognitive control abilities; however, few studies have directly examined the relationship between cognitive performance and ERP indices of performance monitoring. We examined the neuropsychological profile of 89 healthy individuals who performed a modified flanker task. The neuropsychological domains tested included memory, verbal fluency, and attention/executive functioning. Pearson’s correlations and multiple regression analyses showed a significant relationship between measures of attention/executive functioning and ERN amplitude, even when negative affect, reaction time interference, and posterror slowing were controlled. N2 amplitude related only to posterror slowing. The amplitude of the Pe was not significantly related to any cognitive domains. These findings are consistent with recent work indicating that performance monitoring requires attention skills and cognitive flexibility. Implications for the conflict-monitoring and reinforcement-learning theories are discussed.     

Executive functioning as a mediator of the relationship between age and episodic memory in healthy aging

The extent to which age-related differences in executive functioning account for age-related differences in recall from episodic memory was examined in a group of healthy older adults. Fifty-one subjects between the ages of 60 and 91 years were given tests of general cognitive abilities, episodic memory, and executive functioning. A mediational model was proposed with executive functioning as the mediator of the relationship between age and delayed recall. Consistent with this model, regression analyses indicated that, when considered alone, age was a significant predictor of recall (p <.001); however, age was not a significant predictor of recall when the effect of executive functioning was partialled out of the equation (p=.37). Furthermore, the unique contribution of executive functioning accounted for 36% of the variance in recall performance. A significant portion of age-related differences in episodic memory recall, therefore, may be due to age-related differences in the executive skills required for optimal performance on such tests.     

Time of day affects episodic memory in older adults

The neuropsychological test scores of 2030 cognitively normal older adults were examined to evaluate performance patterns as they related to time of day (TOD) at which testing was initiated. Multiple regression analyses were used to examine the association of TOD with scores on seven neuropsychological tests used in the clinical evaluation of dementia. Episodic memory performance was significantly related to TOD, while memory span and verbal fluency were not. Best performance occurred during early morning hours and late afternoon; worst performance occurred mid-day (i.e., noon). These findings may have implications for clinical assessment, the design of research on dementia, and the daily functioning of older adults.     

The relation between cognitive and motor performance and their relevance for children’s transition to school: A latent variable approach

Both theoretically and empirically there is a continuous interest in understanding the specific relation between cognitive and motor development in childhood. In the present longitudinal study including three measurement points, this relation was targeted. At the beginning of the study, the participating children were 5–6-year-olds. By assessing participants’ fine motor skills, their executive functioning, and their non-verbal intelligence, their cross-sectional and cross-lagged interrelations were examined. Additionally, performance in these three areas was used to predict early school achievement (in terms of mathematics, reading, and spelling) at the end of participants’ first grade. Correlational analyses and structural equation modeling revealed that fine motor skills, non-verbal intelligence and executive functioning were significantly interrelated. Both fine motor skills and intelligence had significant links to later school achievement. However, when executive functioning was additionally included into the prediction of early academic achievement, fine motor skills and non-verbal intelligence were no longer significantly associated with later school performance suggesting that executive functioning plays an important role for the motor-cognitive performance link.     

Time of Day Affects Episodic Memory in Older Adults*

ABSTRACT

The neuropsychological test scores of 2,030 cognitively normal older adults were examined to evaluate performance patterns as they related to time of day (TOD) at which testing was initiated. Multiple regression analyses were used to examine the association of TOD with scores on seven neuropsychological tests used in the clinical evaluation of dementia. Episodic memory performance was significantly related to TOD, while memory span and verbal fluency were not. Best performance occurred during early morning hours and late afternoon; worst performance occurred mid-day (i.e., noon). These findings may have implications for clinical assessment, the design of research on dementia, and the daily functioning of older adults.     

Age related differences in metacognitive control: role of executive functioning

To examine whether aging affects metacognitive control, elderly and young adults carried out a readiness-recall task, in which subjects monitor their own learning procedure, allowing strategy manipulation (study time and rehearsal) to be measured. Age differences were observed in metamemory control performance. Younger adults were found to be better at adjusting study time and rehearsal to the task. Moreover, to determine whether age-related differences in strategy manipulation may mediate age-related differences in memory performance, performance on the readiness-recall task was compared to performance on an experimenter-paced task. Results indicated that younger adults recalled significantly more words in the readiness-recall task than in the experimenter test. This was not the case for older adults. Furthermore, a hierarchical regression analysis revealed that age-related differences in strategy manipulation mediate some age-related differences in memory performance. Our aim was also to determine whether metacognitive control is related to executive functions. Thus, all participants were administered standard neuropsychological tests used to assess executive functioning. Significant partial correlation appeared between metamemory control and executive functioning. Finally, a hierarchical regression analysis indicated that age-related decline in metamemory control may be largely the result of executive limitations associated with aging.     

Neuropsychological mediators of the links among age, chronic illness, and everyday problem solving

Reductions in everyday problem solving (EPS) are often reported in older age, although the underlying mechanisms remain unclear. The authors examined the role of 2 variables predicted to mediate (neuropsychological abilities and health status) or moderate (health status) the relationship between age and EPS performance. Toward these ends, they compared EPS and neuropsychological performance in 50 functionally independent adults with chronic kidney disease (CKD) and 64 control participants matched on age and education. Both older age and CKD were associated with worse performance on measures of EPS and memory/executive abilities. Neuropsychological abilities were positively associated with EPS performance. In both the full sample and control participants only, memory/executive functioning mediated the association between presence of chronic illness and EPS. Furthermore, memory/executive functioning partially mediated the link between age and EPS. Findings indicate that relations among age, health status, and EPS are not straightforward. Although performance on neuropsychological measures appeared to underlie EPS declines in chronic illness, increasing age remained independently associated with reduced EPS. The authors discuss implications for models of adult developmental changes in everyday cognition.     

Childhood abuse and neglect and cognitive flexibility in adolescents

Childhood maltreatment (CM) has been associated with diminished executive functioning in children and adults; however, there is a relative paucity of study of executive function in adolescents exposed to CM. Yet, executive dysfunction in adolescence may have important adverse consequences including increased vulnerability to risky behaviors and impaired school functioning. This study investigates the relationship between self-reported CM and an executive function, cognitive flexibility, in adolescents without identified psychiatric disorders. Effects of physical and emotional, abuse and neglect, maltreatment subtypes were explored. Thirty adolescents ages 12-17 years, 50% females, completed the retrospective self-report Childhood Trauma Questionnaire (CTQ) and were administered the Wisconsin Card Sorting Test (WCST). Correlational analyses assessed the relationship between WCST perseverative error scores norm-referenced for age and education with CTQ total scores. The relationship with nonperseverative errors, as well as with physical and emotional abuse and neglect CM subscores, were explored. Total CTQ scores showed significant associations with perseverative errors on the WCST, but not with nonperseverative errors. Significant associations with perseverative errors were seen for physical abuse and physical neglect among the CTQ subscales. The results suggest both physical abuse and physical neglect are associated with diminished cognitive flexibility in adolescents. These effects were detected in adolescents without identified psychiatric diagnoses suggesting the importance of considering executive dysfunction in adolescents exposed to CM who may not meet diagnostic criteria for an Axis I disorder and that tests of perseverative errors, such as those of the WCST, may be sensitive indicators of this dysfunction.     

Assessment of executive function in ADHD adolescents: contribution of performance tests and rating scales

This study aimed to analyze performance on measures of neuropsychological and behavioral executive functions (EF) in adolescents with attention deficit hyperactivity disorder (ADHD), and to evaluate the utility of performance-based tests for predicting scores on behavioral EF ratings. One hundred eighteen adolescents (75 ADHD and 43 controls) aged 12–16 years performed neuropsychological tests and completed a behavior rating scale of EF. The ADHD group presented significantly lower scores than controls on Full Scale IQ (FSIQ) and all indexes of the WISC-IV, except the verbal comprehension index (VCI). The ADHD group had significantly lower scores on performance-based tests of working memory, planning and inhibition, and on EF rating scales. Scores on the cognitive EF working memory, planning and flexibility modestly predicted performance on behavioral EF. The results suggest that the combined use of performance-based tests and rating scales provides valuable complementary information that can improve the assessment of executive domains in ADHD.