Concept: Neuropsychological assessment
There is a growing trend of inactivity among children, which may not only result in poorer physical health, but also poorer cognitive health. Previous research has shown that lower fitness has been related to decreased cognitive function for tasks requiring perception, memory, and cognitive control as well as lower academic achievement.
Caffeine is consumed by over 80% of U.S. adults. This review examines the effects caffeine has on cognitive and physical function, since most real-world activities require complex decision making, motor processing and movement. Caffeine exerts its effects by blocking adenosine receptors. Following low (∼40mg or ∼0.5 mg·kg(-1)) to moderate (∼300mg or 4 mg·kg(-1)) caffeine doses, alertness, vigilance, attention, reaction time and attention improve, but less consistent effects are observed on memory and higher-order executive function, such as judgement and decision making. Effects on physical performance on a vast array of physical performance metrics such as time-to-exhaustion, time-trial, muscle strength and endurance, and high-intensity sprints typical of team sports are evident following doses that exceed about 200mg (∼3mg·kg(-1)). Many occupations, including military, first responders, transport workers and factory shift workers, require optimal physical and cognitive function to ensure success, workplace safety and productivity. In these circumstances, that may include restricted sleep, repeated administration of caffeine is an effective strategy to maintain physical and cognitive capabilities.
Exercise-induced cognitive improvements have traditionally been observed following aerobic exercise interventions; that is, sustained sessions of moderate intensity. Here, we tested the effect of a 6 week high-intensity training (HIT) regimen on measures of cognitive control and working memory in a multicenter, randomized (1:1 allocation), placebo-controlled trial.
Impairments in metacognition, the ability to accurately report one’s performance, are common in patients with psychiatric disorders, where a putative neuromodulatory dysregulation provides the rationale for pharmacological interventions. Previously, we have shown how unexpected arousal modulates metacognition (Allen et al., 2016). Here, we report a double-blind, placebo-controlled, study that examined specific effects of noradrenaline and dopamine on both metacognition and perceptual decision making. Signal theoretic analysis of a global motion discrimination task with adaptive performance staircasing revealed that noradrenergic blockade (40 mg propranolol) significantly increased metacognitive performance (type-II area under the curve, AUROC2), but had no impact on perceptual decision making performance. Blockade of dopamine D2/3 receptors (400 mg amisulpride) had no effect on either metacognition or perceptual decision making. Our study is the first to show a pharmacological enhancement of metacognitive performance, in the absence of any effect on perceptual decision making. This enhancement points to a regulatory role for noradrenergic neurotransmission in perceptual metacognition.
Methylphenidate, modafinil, and caffeine for cognitive enhancement in chess: A double-blind, randomised controlled trial
- European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology
- Published almost 3 years ago
Stimulants and caffeine have been proposed for cognitive enhancement by healthy subjects. This study investigated whether performance in chess - a competitive mind game requiring highly complex cognitive skills - can be enhanced by methylphenidate, modafinil or caffeine. In a phase IV, randomized, double-blind, placebo-controlled trial, 39 male chess players received 2×200mg modafinil, 2×20mg methylphenidate, and 2×200mg caffeine or placebo in a 4×4 crossover design. They played twenty 15-minute games during two sessions against a chess program (Fritz 12; adapted to players' strength) and completed several neuropsychological tests. Marked substance effects were observed since all three substances significantly increased average reflection time per game compared to placebo resulting in a significantly increased number of games lost on time with all three treatments. Treatment effects on chess performance were not seen if all games (n=3059) were analysed. Only when controlling for game duration as well as when excluding those games lost on time, both modafinil and methylphenidate enhanced chess performance as demonstrated by significantly higher scores in the remaining 2876 games compared to placebo. In conjunction with results from neuropsychological testing we conclude that modifying effects of stimulants on complex cognitive tasks may in particular result from more reflective decision making processes. When not under time pressure, such effects may result in enhanced performance. Yet, under time constraints more reflective decision making may not improve or even have detrimental effects on complex task performance.
Two studies are reported comparing the performance of monolingual and bilingual children on tasks requiring different levels of working memory. In the first study, 56 5-year-olds performed a Simon-type task that manipulated working memory demands by comparing conditions based on two rules and four rules and manipulated conflict resolution demands by comparing conditions that included conflict with those that did not. Bilingual children responded faster than monolinguals on all conditions and bilinguals were more accurate than monolinguals in responding to incongruent trials, confirming an advantage in aspects of executive functioning. In the second study, 125 children 5- or 7-year-olds performed a visuospatial span task that manipulated other executive function components through simultaneous or sequential presentation of items. Bilinguals outperformed monolinguals overall, but again there were larger language group effects in conditions that included more demanding executive function requirements. Together, the studies show an advantage for bilingual children in working memory that is especially evident when the task contains additional executive function demands.
BACKGROUND: Head trauma in adolescents has been linked with deficits in attention and executive function that can compromise the performance of everyday tasks. Although previous research has examined this issue using computerized neuropsychological testing, little work has been done using laboratory-based measurements of attention and executive function in this population. A longitudinal analysis of recovery patterns of these measures among adolescents is central to understanding the effects of concussions across the age spectrum. PURPOSE: This study prospectively and longitudinally examined laboratory-based measures of attention and executive function in concussed adolescents sequentially over a 2-month period following injury. METHODS: Two measures of attention and executive function: the Attentional Network Test (ANT) and Task-Switching Test (TST) were administered to 20 concussed adolescents within 72 hours post injury as well as at one week, two weeks, one month, and two months post injury. Twenty healthy, matched control subjects were similarly assessed at the same time intervals. Data were analyzed by two-way, mixed effects analyses of variance to determine the effect of group and time on the dependent variables. RESULTS: Compared with control subjects, the concussed group exhibited a significantly greater switch cost on the TST (p = .038, mean difference value = 38 ms) and a significantly greater reaction time for the ANT conflict effect component (p = .015, mean difference value = 34 ms) for up to two months after injury. CONCLUSIONS: Concussed adolescents have difficulty recovering executive function after injury and may require extended recuperation time before full recovery is achieved. Evaluations focusing on attention and executive function can be useful additions in the assessment and follow-up after head injury.
The current paper proposes the Dysexecutive Luck hypothesis; that beliefs in being unlucky are associated with deficits in executive functioning. Four studies suggest initial support for the Dysexecutive Luck hypothesis via four aspects of executive functioning. Study 1 established that self-reports of dysexecutive symptoms predicted unique variance in beliefs in being unlucky after controlling for a number of other variables previously reported to be related to beliefs around luck. Studies 2 to 4 demonstrated support for the Dysexecutive Luck hypothesis via assessment of executive functioning via: (1) two fundamental executive functions (shifting and inhibition), (2) emotional processes related to executive functioning as described by the Somatic Marker hypothesis, and (3) higher executive functions as accessed via divergent thinking. The findings suggest that individuals' beliefs in being unlucky are accompanied by a range of deficits in executive functioning.
Neuropsychological, Functional, and Behavioral Outcome in South African Traumatic Brain Injury Litigants.
- Archives of clinical neuropsychology : the official journal of the National Academy of Neuropsychologists
- Published about 7 years ago
Few studies address the extent to which, during the process of litigation, individuals with moderate-to-severe traumatic brain injury might malinger in their performance on neuropsychological assessment batteries. This study explored whether financial settlement influenced neuropsychological test performance and activities of daily living in litigants (N = 31) who were tested and interviewed both during litigation and 1 year or more after case settlement. Results showed that neuropsychological test scores did not change from assessment during forensic proceedings to assessment after settlement. Although some improvement was evident in activities of daily living, the gains were small and their clinical significance questionable. We found no evidence that individuals with moderate-to-severe TBI, despite clear potential for secondary gain, malingered or delivered sub-optimal effort during neuropsychological evaluation taking place in the context of litigation.
Prospective memory performance shows a decline in late adulthood. The present article examines the role of 3 main executive function facets (i.e., shifting, updating, and inhibition) as possible developmental mechanisms associated with these age effects. One hundred seventy-five young and 110 older adults performed a battery of cognitive tests including measures of prospective memory, shifting, updating, inhibition, working memory, and speed. Age effects were confirmed in prospective memory and also obtained in shifting, updating, and inhibition. Yet, facets of executive control differently predicted prospective memory performance: While inhibition and shifting were strong predictors of prospective memory performance and also explained age differences in prospective memory, updating was not related to prospective memory performance across adulthood. Furthermore, considering executive function measures increased the amount of explained variance in prospective remembering and reduced the influence of speed. Working memory was not revealed to serve as a significant predictor of prospective memory performance in the present study. These findings clarify the role of different facets of controlled attention on age effects in prospective memory and bear important conceptual implications: Results suggest that some but not all facets of executive functioning are important developmental mechanisms of prospective memory across adulthood beyond working memory and speed. Specifically, inhibition and shifting appear to be essential aspects of cognitive control involved in age-related prospective memory performance. (PsycINFO Database Record © 2012 APA, all rights reserved).