Concept: Neuropsychological test
Ayahuasca is an Amazonian psychoactive plant beverage containing the serotonergic 5-HT(2A) agonist N,N-dimethyltryptamine (DMT) and monoamine oxidase-inhibiting alkaloids (harmine, harmaline and tetrahydroharmine) that render it orally active. Ayahuasca ingestion is a central feature in several Brazilian syncretic churches that have expanded their activities to urban Brazil, Europe and North America. Members of these groups typically ingest ayahuasca at least twice per month. Prior research has shown that acute ayahuasca increases blood flow in prefrontal and temporal brain regions and that it elicits intense modifications in thought processes, perception and emotion. However, regular ayahuasca use does not seem to induce the pattern of addiction-related problems that characterize drugs of abuse. To study the impact of repeated ayahuasca use on general psychological well-being, mental health and cognition, here we assessed personality, psychopathology, life attitudes and neuropsychological performance in regular ayahuasca users (n = 127) and controls (n = 115) at baseline and 1 year later. Controls were actively participating in non-ayahuasca religions. Users showed higher Reward Dependence and Self-Transcendence and lower Harm Avoidance and Self-Directedness. They scored significantly lower on all psychopathology measures, showed better performance on the Stroop test, the Wisconsin Card Sorting Test and the Letter-Number Sequencing task from the WAIS-III, and better scores on the Frontal Systems Behavior Scale. Analysis of life attitudes showed higher scores on the Spiritual Orientation Inventory, the Purpose in Life Test and the Psychosocial Well-Being test. Despite the lower number of participants available at follow-up, overall differences with controls were maintained one year later. In conclusion, we found no evidence of psychological maladjustment, mental health deterioration or cognitive impairment in the ayahuasca-using group.
- Proceedings of the National Academy of Sciences of the United States of America
- Published almost 8 years ago
Recent reports show that fewer adolescents believe that regular cannabis use is harmful to health. Concomitantly, adolescents are initiating cannabis use at younger ages, and more adolescents are using cannabis on a daily basis. The purpose of the present study was to test the association between persistent cannabis use and neuropsychological decline and determine whether decline is concentrated among adolescent-onset cannabis users. Participants were members of the Dunedin Study, a prospective study of a birth cohort of 1,037 individuals followed from birth (1972/1973) to age 38 y. Cannabis use was ascertained in interviews at ages 18, 21, 26, 32, and 38 y. Neuropsychological testing was conducted at age 13 y, before initiation of cannabis use, and again at age 38 y, after a pattern of persistent cannabis use had developed. Persistent cannabis use was associated with neuropsychological decline broadly across domains of functioning, even after controlling for years of education. Informants also reported noticing more cognitive problems for persistent cannabis users. Impairment was concentrated among adolescent-onset cannabis users, with more persistent use associated with greater decline. Further, cessation of cannabis use did not fully restore neuropsychological functioning among adolescent-onset cannabis users. Findings are suggestive of a neurotoxic effect of cannabis on the adolescent brain and highlight the importance of prevention and policy efforts targeting adolescents.
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 over 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.
Non-motor symptoms such as neuropsychiatric and cognitive dysfunction have been found to be common in Parkinson’s disease (PD) but the relation between such symptoms is poorly understood. We focused on alexithymia, an impairment of affective and cognitive emotional processing, as there is evidence for its interaction with cognition in other disorders. Twenty-two non-demented PD patients and 22 matched normal control adults (NC) were administered rating scales assessing neuropsychiatric status, including alexithymia, apathy, and depression, and a series of neuropsychological tests. As expected, PD patients showed more alexithymia than NC, and there was a significant association between alexithymia and disease stage. Alexithymia was associated with performance on non-verbally mediated measures of executive and visuospatial function, but not on verbally mediated tasks. By contrast, there was no correlation between cognition and ratings of either depression or apathy. Our findings demonstrate a distinct association of alexithymia with non-verbal cognition in PD, implicating right hemisphere processes, and differentiate between alexithymia and other neuropsychiatric symptoms in regard to PD cognition.
Evaluating cognitive outcome measures for MS clinical trials: what is a clinically meaningful change?
- Multiple sclerosis (Houndmills, Basingstoke, England)
- Published almost 8 years ago
Brief cognitive assessments are increasingly emphasized in MS treatment studies and clinical care. While much is known about the reliability of several widely-used neuropsychological tests, interpretation of the changes in individual patients is inadequate. The FDA offers guidance on the issue, as related to patient-reported outcomes. Unfortunately, cognitive ability is only weakly correlated with the frequency and severity of self-reported cognitive problems. In this review, we critically examined the psychometrics of neuropsychological testing in MS, emphasizing statistical and anchor-based approaches to interpreting clinically meaningful change. We suggest that there are two paths forward that should be currently pursued. First, to employ co-primary outcomes, including a brief cognitive test and a clinician or observer’s impression on a scale of change, where successful treatment would require showing significant improvement in both measures. Secondly, to work toward showing that when reliable brief cognitive tests are employed, increments of statistically-relevant change would correlate with changes in clinically-relevant anchors (such as vocational disability or clinical relapses with cognitive impairment). The latter goal will allow a more parsimonious and scientifically efficient approach of utilizing only the brief cognitive test as a primary outcome. While some progress has been made in this direction, more research is needed. We are of the opinion that data from both the statistical and clinically meaningful approaches will be necessary to develop valid definitions of meaningful change on cognitive outcome measures, and that it would be best to pursue research using tests that already have well-established reliability and validity.
Impulse control disorders (ICDs) are frequent in Parkinson’s disease (PD). Aim of the present study was to investigate cognition and behaviour in PD patients with and without ICDs, in order to identify potential early clinical features which might be associated to the development of ICDs. We recruited 17 PD patients with ICDs and 17 without ICDs, matched for several clinical variables, without clinically significant cognitive deficits. Assessments included behavioural scales and a neuropsychological battery, including the Iowa Gambling Task (IGT). In patients with ICDs, the total score of the BIS and the Motor Impulsivity subscore were significantly higher than in patients without ICDs. In patients with ICDs, we observed only statistical trends towards a worse performance on neuropsychological tasks (go-no-go subtest of the Frontal Assessment Battery, oral verb naming task, copying of drawings with landmarks) sensitive to frontal lobe dysfunction (FLD) and on the IGT (loss of a greater amount of money, more risky choices). As compared to patients without ICDs, they reported a more than threefold number of errors on the interference subtest of Stroop test, which is also sensitive to FLD. Although this study did not show any significant difference between PD patients presenting ICDs as compared with patients without ICDs on neuropsychological variables, some preliminary evidence was detected suggesting a trend toward a worse performance of the PD-ICD group on few neuropsychological tasks which are at least partially sensitive to frontal lobe dysfunction, including tasks sensitive to dysfunction of ventral fronto-striatal loops.
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 over 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.
Most neuropsychological assessments include at least one measure that is administered, scored, or interpreted by computers or other technologies. Despite supportive findings for these technology-based assessments, there is resistance in the field of neuropsychology to adopt additional measures that incorporate technology components. This literature review addresses the research findings of technology-based neuropsychological assessments, including computer- and virtual reality-based measures of cognitive and functional abilities. We evaluate the strengths and limitations of each approach, and examine the utility of technology-based assessments to obtain supplemental cognitive and behavioral information that may be otherwise undetected by traditional paper-and-pencil measures. We argue that the potential of technology use in neuropsychological assessment has not yet been realized, and continued adoption of new technologies could result in more comprehensive assessment of cognitive dysfunction and in turn, better informed diagnosis and treatments. Recommendations for future research are also provided.
We report the clinical assessment of J.P., an 86 year-old man with Broca’s aphasia complaining of memory problems. Our aim was to objectively investigate his level of cognitive functioning using standardized neuropsychological tests in order to determine the nature of his memory impairment. J.P.’s medical history included left-middle cerebral artery (left-MCA) stroke, high frequency hearing loss, macular degeneration, and a recent hospitalization related to a fall. Results from his neuropsychological testing and from information gathered during the clinical interview with his wife suggested that a deficit in executive functioning might have been the source for some of his perceived memory problems. We were unable to detect any progressive cognitive decline that might have been suggestive of something more sinister. Despite his age J.P. was a fully functioning and highly contributing member of his society who was completing quite complex activities of daily living (ADLs). We provided J.P. with a compensatory set of strategies in order for him to circumvent his executive difficulties and impairment in expressive language. In the elderly population survivors of stroke are continuing to rise with improvements in drug treatment and primary care. This case study is important as it provides information on neuropsychological assessment in aphasia; and draws attention to valuable information in a client’s clinical history that might help clarify the prognosis.
The impact of omega-3 long-chain polyunsaturated fatty acids (LCPUFAs) on cognition is heavily debated. In the current study, the possible association between omega-3 LCPUFAs in blood and cognitive performance of 266 typically developing adolescents aged 13-15 years is investigated. Baseline data from Food2Learn, a double-blind and randomized placebo controlled krill oil supplementation trial in typically developing adolescents, were used for the current study. The Omega-3 Index was determined with blood from a finger prick. At baseline, participants finished a neuropsychological test battery consisting of the Letter Digit Substitution Test (LDST), D2 test of attention, Digit Span Forward and Backward, Concept Shifting Test and Stroop test. Data were analyzed with multiple regression analyses with correction for covariates. The average Omega-3 Index was 3.83% (SD 0.60). Regression analyses between the Omega-3 Index and the outcome parameters revealed significant associations with scores on two of the nine parameters. The association between the Omega-3 Index and both scores on the LDST (β = 0.136 and p = 0.039), and the number of errors of omission on the D2 (β = -0.053 and p = 0.007). This is a possible indication for a higher information processing speed and less impulsivity in those with a higher Omega-3 Index.