Failure to evaluate the validity of an examinee's neuropsychological test performance can alter prediction of external criteria in research investigations, and in the individual case, result in inaccurate conclusions about the degree of impairment resulting from neurological disease or injury. The terms performance validity referring to validity of test performance (PVT), and symptom validity referring to validity of symptom report (SVT), are suggested to replace less descriptive terms such as effort or response bias. Research is reviewed demonstrating strong diagnostic discrimination for PVTs and SVTs, with a particular emphasis on minimizing false positive errors, facilitated by identifying performance patterns or levels of performance that are atypical for bona fide neurologic disorder. It is further shown that false positive errors decrease, with a corresponding increase in the positive probability of malingering, when multiple independent indicators are required for diagnosis. The rigor of PVT and SVT research design is related to a high degree of reproducibility of results, and large effect sizes of d=1.0 or greater, exceeding effect sizes reported for several psychological and medical diagnostic procedures. (JINS, 2012, 18, 1–7)

Symptom validity testing (SVT) has become a major theme of contemporary neuropsychological research. However, many issues about the meaning and interpretation of SVT findings will require the best in research design and methods to more precisely characterize what SVT tasks measure and how SVT test findings are to be used in neuropsychological assessment. Major clinical and research issues are overviewed including the use of the “effort” term to connote validity of SVT performance, the use of cut-scores, the absence of lesion-localization studies in SVT research, neuropsychiatric status and SVT performance and the rigor of SVT research designs. Case studies that demonstrate critical issues involving SVT interpretation are presented. (JINS, 2012, 18, 1–11)

Schizophrenia and schizotypal personality disorder share common clinical profiles, neurobiological and genetic substrates along with Prepulse Inhibition and cognitive deficits; among those, executive, attention, and memory dysfunctions are more consistent. Schizotypy is considered to be a non-specific “psychosis-proneness,” and understanding the relationship between schizotypal traits and cognitive function in the general population is a promising approach for endophenotypic research in schizophrenia spectrum disorders. In this review, findings for executive function, attention, memory, and Prepulse Inhibition impairments in psychometrically defined schizotypal subjects have been summarized and compared to schizophrenia patients and their unaffected first-degree relatives. Cognitive flexibility, sustained attention, working memory, and Prepulse Inhibition impairments were consistently reported in high schizotypal subjects in accordance to schizophrenia patients. Genetic studies assessing the effects of various candidate gene polymorphisms in schizotypal traits and cognitive function are promising, further supporting a polygenic mode of inheritance. The implications of the findings, methodological issues, and suggestions for future research are discussed. (JINS, 2012, 18, 1–14)

Both HIV infection and high levels of early life stress (ELS) have been related to abnormalities in frontal-subcortical structures, yet the combined effects of HIV and ELS on brain structure and function have not been previously investigated. In this study we assessed 49 non-demented HIV-seropositive (HIV+) and 47 age-matched HIV-seronegative healthy control (HC) adults. Levels of ELS exposure were quantified and used to define four HIV-ELS groups: HC Low-ELS (N = 20); HC High-ELS (N = 27); HIV+ Low-ELS (N = 24); HIV+ High-ELS (N = 25). An automated segmentation tool measured volumes of brain structures known to show HIV-related or ELS-related effects; a brief neurocognitive battery was administered. A significant HIV-ELS interaction was observed for amygdala volumes, which was driven by enlargements in HIV+ High-ELS participants. The HIV+ High-ELS group also demonstrated significant reductions in psychomotor/processing speed compared with HC Low-ELS. Regression analyses in the HIV+ group revealed that amygdala enlargements were associated with higher ELS, lower nadir CD4 counts, and reduced psychomotor/processing speed. Our results suggest that HIV infection and high ELS interact to increase amygdala volume, which is associated with neurocognitive dysfunction in HIV+ patients. These findings highlight the lasting neuropathological influence of ELS and suggest that high ELS may be a significant risk factor for neurocognitive impairment in HIV-infected individuals. (JINS, 2012, 19, 1–12)

Systematic cognitive training produces long-term improvement in cognitive function and less difficulty in performing activities of daily living. We examined whether cognitive training was associated with reduced rate of incident dementia. Participants were from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study (n = 2,802). Incident dementia was defined using a combination of interview- and performance-based methods. Survival analysis was used to determine if ACTIVE treatment affected the rate of incident dementia during 5 years of follow-up. A total of 189 participants met criteria for incident dementia. Baseline factors predictive of incident dementia were older age, male gender, African American race, fewer years of education, relationship other than married, no alcohol use, worse MMSE, worse SF-36 physical functioning, higher depressive symptomatology, diabetes, and stroke (all p < .05). A multivariable model with significant predictors of incident dementia and training group revealed that cognitive training was not associated with a lower rate of incident dementia. Cognitive training did not affect rates of incident dementia after 5 years of follow-up. Longer follow-up or enhanced training may be needed to fully explore the preventive capacity of cognitive training in forestalling onset of dementia. (JINS, 2012, 18, 1–9)

This study sought to characterize neuropsychological functioning in MJ-using adolescents and emerging adults (ages 18–26) and to investigate whether gender moderated these effects. Data were collected from 59 teens and emerging adults including MJ users (n = 23, 56% female) and controls (n = 35, 50% female) aged 18–26 (M = 21 years). Exclusionary criteria included independent Axis I disorders (besides SUD), and medical and neurologic disorders. After controlling for reading ability, gender, subclinical depressive symptoms, body mass index, and alcohol and other drug use, increased MJ use was associated with slower psychomotor speed/sequencing ability (p < .01), less efficient sustained attention (p < .05), and increased cognitive inhibition errors (p < .03). Gender significantly moderated the effects of MJ on psychomotor speed/sequencing ability (p < .003) in that males had a more robust negative relationship. The current study demonstrated that MJ exposure was associated with poorer psychomotor speed, sustained attention and cognitive inhibition in a dose-dependent manner in young adults, findings that are consistent with other samples of adolescent MJ users. Male MJ users demonstrated greater cognitive slowing than females. Future studies need to examine the neural substrates underlying with these cognitive deficits and whether cognitive rehabilitation or exercise interventions may serve as a viable treatments of cognitive deficits in emerging adult MJ users. (JINS, 2012, 18, 1–11)

Huntington's disease (HD) is a genetic neurodegenerative disorder affecting the basal ganglia. These subcortical structures are particularly important for motor functions, response selection and implicit learning. In the current study, we have assessed prodromal and symptomatic HD participants with an implicit contextual learning task that is not based on motor learning, but on a purely visual implicit learning mechanism. We used an implicit contextual learning task in which subjects need to locate a target among several distractors. In half of the trials, the positions of the distractors and target stimuli were repeated. By memorizing this contextual information, attention can be guided faster to the target stimulus. Nine symptomatic HD participants, 16 prodromal HD participants and 22 control subjects were included. We found that the responses of the control subjects were faster for the repeated trials than for the new trials, indicating that their visual search was facilitated when repeated contextual information was present. In contrast, no difference in response times between the repeated and new trials was found for the symptomatic and prodromal HD participants. The results of the current study indicate that both prodromal and symptomatic HD participants are impaired on an implicit contextual learning task. (JINS, 2012, 18, 1–8)

Prospective memory (PM) is the ability to remember to perform a future action at a specified later time, which is investigated through the use of event-based and time-based tasks. Prior investigations have found that PM is impaired following traumatic brain injury (TBI). However, there is limited information regarding the cognitive functions that mediate TBI and PM performance. Thus, this study investigated time-based PM in TBI patients, and the relationship among time-based PM, time perception, and executive functions. To accomplish this objective, 18 severe TBI patients and 18 healthy matched controls performed a time-based PM task, a time reproduction task, and two executive functions (Stroop and n-back) tasks. While both groups increased their monitoring frequency close to the target time, TBI patients monitored more and were less accurate than healthy controls at the target time confirming the time-based PM dysfunction in these patients. Importantly, executive functions, particularly inhibition and updating abilities, were strongly related to time-based PM performance; both time perception and executive functions are involved in time-based prospective memory in controls, whereas, only executive functions appear to be involved in TBI time-based prospective memory performance. (JINS, 2012, 18, 1–9)

Prospective memory (PM) is the ability to remember to execute delayed intentions. Previous studies indicate that PM is impaired in persons with mild cognitive impairment (MCI) and dementia, but the extent, nature, and cognitive correlates are unclear. A meta-analytic review was, therefore, performed (literature search 1990 to July 2011) on case-control studies on PM in dementia (10 studies, 336 patients, 505 controls) and MCI (7 studies, 225 patients, 253 controls). Differences between event-based and time-based PM and between measures of prospective and retrospective memory were examined, as well as correlations with other cognitive functions. Results showed that patients with dementia or MCI exhibit large deficits in PM (Hedges’ d −1.62 [95% confidence interval −1.98 to −1.27; p < .0001] for dementia; −1.24 [−1.51 to −0.995; p < .0001] for MCI; difference dementia vs. MCI: QM = 1.94, p = .16). Impairments were comparable in size for event-based and time-based PM (p > .05), as well as for prospective and retrospective memory (p > .05). PM showed modest correlations with measures of retrospective memory (median r = 0.27) and executive functioning (median r = 0.30). PM appears a valid construct in neuropsychological assessment in patients with dementia or MCI, but more insight is needed in the optimal characteristics of PM tasks to be used in clinical practice. (JINS, 2012, 18, 1–11)

Antipsychotic medications can contribute to neurocognitive and motor impairments, but specific links to individualized pharmacological treatment regimens are unclear. In 68 participants with stabilized first-episode psychosis (FEP), we investigated the links between neuropsychological functions and an established anticholinergic potency index and a new D2 antagonist potency index developed in our lab. Each participant's psychiatric medication regimen was converted into estimated receptor antagonist loads based upon specific medication dosage(s) and reported in vitro brain muscarinic cholinergic and D2 receptor antagonism. In addition to the global neuropsychological impairments of FEP participants, the findings supported the hypothesized links between receptor antagonist loads and specific deficits. Higher anticholinergic load was associated with poorer delayed verbal memory but was not related to motor functioning. In contrast, higher D2 load was associated with poorer motor functioning but not verbal memory. These selective antagonist load associations explained 19% of the variance in motor functioning and 17% of the variance in delayed verbal memory. Evidently, some of the neuropsychological impairments found in persons with FEP are selectively related to the specific pharmacodynamics and the dosing of their medication regimens. Moreover, these effects can be readily estimated from practical and inexpensive indices. (JINS, 2012, 18, 1–11)

Difficulties related to inhibition and set-shifting have been suggested as possible endophenotypes of Attention Deficit Hyperactivity Disorder (ADHD). However, such difficulties have not been consistently found in studies using standard neuropsychological tests. This has been partly explained by the complexity of these tests and the need to include contrast measures which control for more basic functions. The purpose of the present study was to examine whether difficulties related to inhibition and set-shifting in adult ADHD patients could be revealed by the Color Word Interference Test (CWIT) from the Delis Kaplan Executive Function System (D-KEFS). A clinically recruited group of adults with ADHD (n = 60) obtained significantly lower scores than population derived controls (n = 60) on both primary summary (p < .001) and contrast measures (p = .004) of set-shifting. The differences between the groups remained statistically significant after controlling for intellectual function and working memory (p = .003). However, no significant differences between the groups were observed on any measure of inhibition. The study indicates that adults with ADHD have specific difficulties with set-shifting as measured by the CWIT, difficulties that probably also reflect problems related to executive function in their daily life. (JINS, 2012, 18, 1–10)

Memory problems are common in patients with a range of neurological conditions, but there have been few attempts to provide and evaluate the usefulness of memory training for groups of neurological outpatients. We used a waitlist-controlled trial design to assess the effectiveness of a newly created, 6-session intervention, which involved training in the use of compensatory strategies as well as education regarding memory function, neurological damage, sleep and lifestyle factors that have an impact on memory. Fifty-six patients with neurological conditions (e.g., stroke, epilepsy) and memory complaints completed the training and assessments. Outcomes were evaluated in terms of reported strategy use as well as objective and subjective measures of anterograde and prospective memory. Training resulted in significant improvements on number of strategies used, scores on the Rey Auditory Verbal Learning Test (total learning and delayed recall) and self-report on the Comprehensive Assessment of Prospective Memory. Improvements were stable at 3-month follow-up. Better individual outcomes were related to lower baseline memory scores, fewer symptoms of depression and greater self-awareness of memory function. Overall the study provides encouraging results to indicate that patients with neurological conditions such as stroke and epilepsy can show improvements in memory after a relatively short group-based intervention. (JINS, 2012, 18, 1–11)

Two major challenges facing researchers interested in cognitive change are that measures of change are often not very reliable, and they may reflect effects of prior test experience in addition to the factors of primary interest. One approach to dealing with these problems is to obtain multiple measures of change on parallel versions of the same tests in a measurement burst design. A total of 783 adults performed three parallel versions of cognitive tests on two occasions separated by an average of 2.6 years. Performance increased substantially across the three sessions within each occasion, and for all but vocabulary ability these within-occasion improvements were considerably larger than the between-occasion changes. Reliabilities of the changes in composite scores were low, but averages of the three changes had larger, albeit still quite modest, reliabilities. In some cognitive abilities individual differences were evident in the relation of prior test experience and the magnitude of longitudinal change. Although multiple assessments are more time consuming than traditional measurement procedures, the resulting estimates of change are more robust than those from conventional methods, and also allow the influence of practice on change to be systematically investigated. (JINS, 2012, 18, 1–8)

The objective of this study is to assess attention in recently diagnosed relapsing-remitting multiple sclerosis patients. Twenty-seven patients with early multiple sclerosis and low clinical disability scores (EDSS<2) and 27 sex-, age-, and education-matched healthy controls underwent attention assessment using the Attentional Network Test, a computerized task designed to measure efficiency independently in 3 attentional networks (Alerting, Orienting and Executive Control). MS patients had significantly less efficiency in the Alerting network (p = .006). In contrast, in the Orienting and Executive Control networks, they did not differ from controls. A significant interaction between Alerting and Executive Control was also found in the MS patients (p = .007). Early relapsing-remitting multiple sclerosis particularly affects the Alerting domain of attention, whereas the Orienting and Executive Control domains are not affected. (JINS, 2012, 18, 1–7)

We examined two-wave longitudinal changes in two indicators of neurocognitive speed (i.e., mean rate, intraindividual variability) using one simple and three complex reaction time tasks. Participants included idiopathic Parkinson's disease (PD) patients, with and without incipient dementia, and normal controls. At baseline, there were 45 patients (26 men, 19 women) with idiopathic PD who ranged from 65 to 84 years (M = 71.3; SD = 4.5) and 47 matched controls (27 men, 20 women) who ranged from 65 to 84 years (M = 71.4; SD = 4.9). The 18-month longitudinal sample comprised of 74 returning participants (43 controls; 31 PD patients) who had no cognitive impairment or dementia at both waves. Ten of the 31 PD patients returning for Time 3 had dementia or cognitive impairment. These constituted the PD with incipient dementia (PDID) group. Repeated measures analyses of variance showed that the PD and PDID groups were slower over time on the reaction time tasks, whereas the controls improved their performance over time on all tasks. Inconsistency distinguished the two clinical groups (i.e., the PDID group but not the PD group became more inconsistent over time). Changes in neurocognitive speed and inconsistency may be valid clinical markers of PDID. (JINS, 2012, 18, 1–9)

Individuals with anorexia nervosa (AN) are often characterized as possessing excessive self-control and are unusual in their ability to reduce or avoid the consumption of palatable foods. This behavior promotes potentially life-threatening weight loss and suggests disturbances in reward processing. We studied whether individuals with AN showed evidence of increased self-control by examining the tendency to delay receipt of a monetary, non-food related, reward. Underweight AN (n = 36) and healthy controls (HC, n = 28) completed a monetary intertemporal choice task measuring delay discounting factor. Individuals with AN reduced the value of a monetary reward over time significantly less than HC (F[1,61] = 5.03; p = 0.029). Secondary analyses indicated that the restricting subtype of AN, in particular, showed significantly less discounting than HC (F[1,46] = 8.3; p = 0.006). These findings indicate that some individuals with AN show less temporal discounting than HC, suggestive of enhanced self-control that is not limited to food consumption. This is in contrast to other psychiatric disorders, for example, substance abuse, which are characterized by greater discounting. Though preliminary, these findings suggest that excessive self-control may contribute to pathological processes and individuals with AN may have neuropsychological characteristics that enhance their ability to delay reward and thereby may help to maintain persistent food restriction. (JINS, 2012, 18, 1–8)