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)

The relationship between assistive technology for cognition (ATC) and cognitive function was examined using a systematic review. A literature search identified 89 publications reporting 91 studies of an ATC intervention in a clinical population. The WHO International Classification of Functioning, Disability and Health (ICF) was used to categorize the cognitive domains being assisted and the tasks being performed. Results show that ATC have been used to effectively support cognitive functions relating to attention, calculation, emotion, experience of self, higher level cognitive functions (planning and time management) and memory. The review makes three contributions: (1) It reviews existing ATC in terms of cognitive function, thus providing a framework for ATC prescription on the basis of a profile of cognitive deficits, (2) it introduces a new classification of ATC based on cognitive function, and (3) it identifies areas for future ATC research and development. (JINS, 2012, 18, 1–19)

The National Institutes of Health (NIH) Magnetic Resonance Imaging (MRI) Study of Normal Brain Development is a landmark study in which structural and metabolic brain development and behavior are followed longitudinally from birth to young adulthood in a population-based sample of healthy children. Cross-sectional findings from the neuropsychological test battery have been previously described (Waber et al., 2007). The present report details 4-year longitudinal neuropsychological outcomes for those children who were aged 6 to 18 years at baseline (N = 383), of whom 219 (57.2%) completed all 3 visits. Primary observations were (1) individual children displayed considerable variation in scores across visits on the same measures; (2) income-related differences were more prominent in the longitudinal than in the cross-sectional data; (3) no association between cognitive and behavioral measures and body mass index; and (4) several measures showed practice effects, despite the 2-year interval between visits. These data offer an unparalleled opportunity to observe normative performance and change over time on a set of standard and commonly used neuropsychological measures in a population-based sample of healthy children. They thus provide important background for the use and interpretation of these instruments in both research settings and clinical practice. (JINS, 2012, 18, 179–190)

This study examined everyday action impairment in participants with Parkinson's disease dementia (PDD) by comparison with participants with Parkinson's disease-no dementia (PD) or Alzheimer's disease (AD) and in reference to a neuropsychological model. Participants with PDD (n = 20), PD (n = 20), or AD (n = 20) were administered performance-based measures of everyday functioning that allowed for the quantification of overall performance and error types. Also, caregiver ratings of functional independence were obtained. On performance-based tests, the PDD group exhibited greater functional impairment than the PD group but comparable overall impairment relative to the AD group. Error patterns did not differ between PDD and PD participants but the PDD group demonstrated a higher proportion of commission errors and lower proportion of omission errors relative to the AD group. Hierarchical regression analyses showed omission errors were significantly predicted by neuropsychological measures of episodic memory, whereas commission errors were predicted by both measures of general dementia severity (MMSE) and executive control. Everyday action impairment in PDD differs quantitatively from PD but qualitatively from AD and may be characterized by a relatively high proportion of commission errors—an error type associated with executive control deficits. (JINS, 2012, 18, 1–12)

Olfactory hallucinations (OHs) are present in a significant minority of people with schizophrenia, yet these symptoms are under-researched and poorly understood. This study aimed to identify the neuropsychological impairments that associate with OHs in schizophrenia. Patients with schizophrenia or schizoaffective disorder were classified into an OH group and a group with auditory-verbal hallucinations (AVHs) and no lifetime history of OHs. Patients were age- and gender-matched to a healthy control group. All participants were assessed using: a test of odor identification; decision-making and socio-emotional tests of orbitofrontal cortex (OFC) and amygdala function; and a battery of standardized executive tests. Patients, as a whole, performed more poorly than controls on the tests of odor identification, emotion processing and executive function, consistent with previous research. Only two tests of OFC functioning: the Object Alternation Task, taken from Oscar-Berman and Zola-Morgan's (1980a, 1980b) Comparative Neuropsychological Tasks, and a test of “faux pas” understanding discriminated between the OH and AVH patients. Findings provide the first preliminary support for OH-specific neuropsychological impairments associated with OFC dysfunction in schizophrenia. (JINS, 2012, 18, 1–10)

Converging evidence, including observations in patients with Parkinson's disease (PD), suggests that dopamine plays a role in impulsivity. This multi-faceted construct includes considerations of both time and risk; determining how these more specific processes are affected by PD and dopaminergic treatment can inform neurobiological models. We examined the effects of PD and its treatment on temporal discounting and risky decision-making in a cohort of 23 mild-moderate PD patients and 20 healthy participants. Patients completed the Balloon Analogue Risk Task and a temporal discounting paradigm both on and off their usual dopamine replacement therapy. PD patients did not differ from controls in their initial risk-taking on the Balloon Analogue Risk Task, but took progressively more risks across trials when on medication. A subset of patients and controls was tested again, 1.5–3 years later, to explore the effects of disease progression. On follow-up, baseline risk-taking diminished in patients, but the tendency to take increasing risks across trials persisted. Neither disease progression nor its treatment affected the temporal discounting rate. These findings suggest a different neural basis for temporal discounting and risk-taking, and demonstrate that risk-taking can be further decomposed into initial and trial-by-trial effects, with dopamine affecting only the latter. (JINS, 2012, 18, 1–10)

Libon et al. (2010) provided evidence for three statistically determined clusters of patients with mild cognitive impairment (MCI): amnesic (aMCI), dysexecutive (dMCI), and mixed (mxMCI). The current study further examined dysexecutive impairment in MCI using the framework of Fuster's (1997) derailed temporal gradients, that is, declining performance on executive tests over time or test epoch. Temporal gradients were operationally defined by calculating the slope of aggregate letter fluency output across 15-s epochs and accuracy indices for initial, middle, and latter triads from the Wechsler Memory Scale-Mental Control subtest (Boston Revision). For letter fluency, slope was steeper for dMCI compared to aMCI and NC groups. Between-group Mental Control analyses for triad 1 revealed worse dMCI performance than NC participants. On triad 2, dMCI scored lower than aMCI and NCs; on triad 3, mxMCI performed worse versus NCs. Within-group Mental Control analyses yielded equal performance across all triads for aMCI and NC participants. mxMCI scored lower on triad 1 compared to triads 2 and 3. dMCI participants also performed worse on triad 1 compared to triads 2 and 3, but scored higher on triad 3 versus triad 2. These data suggest impaired temporal gradients may provide a useful heuristic for understanding dysexecutive impairment in MCI. (JINS, 2012, 18, 20–28)

We investigated differences between Alzheimer's disease (AD) and vascular dementia (VaD) from the appearance of the first cognitive symptoms, focusing on both time of onset and rate of accelerated decline for different cognitive functions before dementia diagnosis. Data from a longitudinal population-based study were used, including 914 participants (mean age = 82.0 years, SD = 5.0) tested with a cognitive battery (word recall and recognition, Block Design, category fluency, clock reading) on up to four occasions spanning 10 years. We fit a series of linear mixed effects models with a change point to the cognitive data, contrasting each dementia group to a control group. Significant age-related decline was observed for all five cognitive tasks. Relative to time of diagnosis, the preclinical AD persons deviated from the normal aging curve earlier (up to 9 years) compared to the preclinical VaD persons (up to 6 years). However, once the preclinical VaD persons started to decline, they deteriorated at a faster rate than the preclinical AD persons. The results have important implications for identifying the two dementia disorders at an early stage and for selecting cognitive tasks to evaluate treatment effects for persons at risk of developing AD and VaD. (JINS, 2012, 18, 191–199)

The present study investigates selective attention and verbal free recall in amyotrophic lateral sclerosis (ALS) and examines the contribution of selective attention, encoding, consolidation, and retrieval memory processes to patients’ verbal free recall. We examined 22 non-demented patients with sporadic ALS and 22 demographically related controls using Stroop Neuropsychological Screening Test (SNST; selective attention) and Rey Auditory Verbal Learning Test (RAVLT; immediate & delayed verbal free recall). The item-specific deficit approach (ISDA) was applied to RAVLT to evaluate encoding, consolidation, and retrieval difficulties. ALS patients performed worse than controls on SNST (p < .001) and RAVLT immediate and delayed recall (p < .001) and showed deficient encoding (p = .001) and consolidation (p = .002) but not retrieval (p = .405). Hierarchical regression analysis revealed that SNST and ISDA indices accounted for: (a) 91.1% of the variance in RAVLT immediate recall, with encoding (p = .016), consolidation (p < .001), and retrieval (p = .032) significantly contributing to the overall model and the SNST alone accounting for 41.6%; and (b) 85.2% of the variance in RAVLT delayed recall, with consolidation (p < .001) and retrieval (p = .008) significantly contributing to the overall model and the SNST alone accounting for 39.8%. Thus, selective attention, encoding, and consolidation, and to a lesser extent of retrieval, influenced both immediate and delayed verbal free recall. Concluding, selective attention and the memory processes of encoding, consolidation, and retrieval should be considered while interpreting patients’ impaired free recall. (JINS, 2012, 18, 1–10)

The purpose of this study was to investigate the effects of pediatric traumatic brain injury (TBI) on verbal and visual-spatial working memory (WM). WM tasks examined memory span through recall of the last item of a series of stimuli. Additionally, both verbal and visual-spatial tests had a dual-task condition assessing the effect of increasing demands on the central executive (CE). Inhibitory control processes in verbal WM were examined through intrusion errors. The TBI group (n = 73) performed more poorly on verbal and visual-spatial WM tasks than orthopedic-injured children (n = 30) and non-injured children (n = 40). All groups performed more poorly on the dual-task conditions, reflecting an effect of increasing CE load. This effect was not greater for the TBI group. There were no group differences in intrusion errors on the verbal WM task, suggesting that problems in WM experienced by children with TBI were not primarily due to difficulties in inhibitory control. Finally, injury-related characteristics, namely days to follow commands, accounted for significant variance in WM performance, after controlling for relevant demographic variables. Findings suggest that WM impairments in TBI are general rather than modality-specific and that severity indices measured over time are better predictors of WM performance than those taken at a single time point. (JINS, 2012, 18, 29–38)

In this study we examined the association between intrauterine growth, indexed either as a categorical variable or continuous dimension, and neuropsychological outcome, in a very low birth weight (VLBW) sample of 143 preschoolers. When the commonly used split at the 10th percentile rank was applied to classify intrauterine growth restriction (IUGR), we found that the growth restricted group (n = 25) exhibited significantly poorer performance in the global motor domain, but not on any other neuropsychological measure. In contrast, when adequacy of intrauterine growth was indexed by standardized birth weight, a continuous dimension, this early risk factor explained a unique portion of the variance in global cognitive abilities and visuospatial skills, as well as in global, fine, and gross motor skills. These findings are consistent with recent magnetic resonance imaging data disclosing global neurodevelopmental changes in the brains of preterm infants with IUGR. When cases classified with IUGR (<10th percentile) were excluded, the relationship between adequacy of intrauterine growth and global cognitive abilities remained significant despite range restriction. Hence, an association between appropriateness of intrauterine growth and global intellectual outcome may be observed even within the population of VLBW preschoolers with adequate standardized birth weight. (JINS, 2012, 18, 200–211)

This study aimed to examine the relationship between perspective-taking and impaired decision-making in patients with ventromedial prefrontal (VM) lesions, using the Ultimatum Game (UG). In the UG, two players split a sum of money and one player proposes a division while the other can accept or reject this. Eight patients with VM damage and 18 healthy controls participated as responders in a modified version of the UG, in which identical offers can generate different rejection rates depending on the other offers available to the proposer. Participants had to either accept or reject offers of 2:8 NIS (2NIS for them and 8 NIS for the proposer), which were paired with one of four different possible offers (5:5, 4:6, 2:8, 8:2). Results indicate that the controls more often rejected offers of 2:8 when the alternative was 4:6 (a greedy alternative) than when the alternative was 5:5 (fair alternative), whereas the VM patients showed the opposite pattern of decision-making. Additionally, the overall rejection rates were higher in patients as compared to controls. Furthermore, scores on a perspective-taking scale were negatively correlated with rejection rates in the patient group, suggesting that perspective-taking deficits may account for impaired decision-making in VM patients. (JINS, 2012, 18, 952–961)