This study examined the relationship between processing speed (PS) and working memory (WM), as measured by performance on an n-back task, in relapsing-remitting multiple sclerosis (RRMS) patients. Simple PS was defined as reaction time (RT) on the 0-back task and complex PS was defined as RT on both the 1-back and 2-back tasks. Participants were administered all three n-back tasks (0-, 1-, and 2-back). Total correct responses, total dyads, and RTs were recorded. As expected, RT for all participants slowed as WM load increased. MS patients had slower RTs than controls across all tasks, and the difference between groups for RT was greatest during the 2-back task. When RT for simple PS (0-back) was parsed from the 1- and 2-back tasks, MS patients still showed impaired complex PS compared to controls. MS patients also made significantly fewer total correct responses and had fewer dyads than controls only on the 2-back task. These findings suggest that both WM and PS deficits are present in RRMS, and that as WM demand increases (from 1- to 2-back) both PS and WM deficits become more prominent. (JINS, 2007, 13, 417–423.)

A critical focus of neuropsychological research is to identify unbiased ways to compare heterogeneous groups on background variables relevant to neuropsychological performance. Whereas recent work has pointed to single word reading as a less culturally biased measure of educational experience than years of education, the extent to which reading score captures a broad range of educational experience and does so consistently across ethnic and language groups is unknown. The current study evaluated reading in relation to years of education in English-speaking Whites, Blacks, and Hispanics, and Spanish-speaking Hispanic older persons (n = 342). Consistent with previous work, reading scores at each grade level were lower in English speaking ethnic minorities than in Whites, supporting the idea that variables related to lifetime educational experience are often confounded with ethnicity. Standardized reading scores were highest in the Spanish speakers; however, interpretation of this difference is limited because scores were necessarily derived using separate normative samples. Importantly, the slopes of reading score by years of education were comparable across all groups. That is, reading scores rose consistently with years of education independently of ethnicity or language, suggesting that such scores can be treated comparably for theoretical and statistical purposes in multiethnic and multilingual samples. (JINS, 2007, 13, 228–236.)

As currently defined, it is not clear whether Nonverbal Learning Disabilities (NLD) should be considered a matter of kind or magnitude (Meehl, 1995). The taxonicity of NLD, or the degree to which it is best construed as discrete versus continuous, has not been investigated using methods devised for this purpose. Latent Class Analysis (LCA) is a method for finding subtypes of latent classes from multivariate categorical data. This study represents an application of LCA on a sample of children and adolescents with spina bifida myelomeningocele (SBM) (N = 44), those presenting with features of NLD (N = 28) but no medical condition, and control volunteers (N = 44). The two-class solution provided evidence for the presence of a taxon with an estimated base-rate in the SBM group of .57. Indicator validities (the conditional probabilities of indicator endorsement in each latent class) suggest a somewhat different priority for defining NLD than is typically used by researchers investigating this disorder. A high degree of correspondence between LCA classifications and those based on a more conventional algorithm provided evidence for the validity of this approach. (JINS, 2007, 13, 50–58.)

To evaluate the progression of cognitive decline in multiple sclerosis (MS) patients and the susceptibility of the Multiple Sclerosis Functional Composite (MSFC) Paced Auditory Serial Addition Test (PASAT) to change, we conducted a 1-year follow-up with a comprehensive neuropsychological examination to 19 initially cognitively impaired and 26 cognitively intact relapsing–remitting MS patients, and to 48 healthy controls. The results indicated that the cognitive performance of MS patients remained relatively stable. Healthy controls tended to perform better on most neuropsychological measures at follow-up, the same was not observed in the MS groups. PASAT showed a significant difference between the groups: the cognitively impaired group tended to deteriorate, whereas the control group and the cognitively intact group improved. The change in PASAT could not be explained by the background variables, for example, mood, quality of life, or nervousness. Therefore, the MSFC-PASAT seems to be a sensitive measure to show clinical change in the cognitive status. (JINS, 2007, 13, 791–798.)

Language decline is usually the fastest and predominant change in primary progressive aphasia (PPA). In Alzheimer's disease (AD), it is usually associated with global cognitive deficits. Decreased speech output, reduced conversational initiation, echolalia, and changes in the pragmatics of conversation are seen in the behavioral variant of frontotemporal dementia (FTD-bv), however, the evolution of language disturbance in FTD-bv patients is rarely examined systematically with a standardized language battery. We aimed to longitudinally track the nature of language change in FTD-bv, PPA, and AD using a standardized measure of language functioning. We also explored the nature of language deficits between semantic dementia (SD) patients and the fluent subgroup of PPA patients. The Western Aphasia Battery was administered to 105 AD, 20 FTD-bv, 54 PPA, and 10 SD patients on 2 occasions with approximately 1 year between assessments. Ninety-nine of these patients were examined an additional year. FTD-bv and PPA patients showed a faster language decline than AD patients. The eventual overlap in language functioning in FTD-bv and PPA suggests that these syndromes belong to the same spectrum of disorders. In conclusion, longitudinal language assessment provides us with a unique understanding of the evolution and progression of language deterioration in various dementias. (JINS, 2007, 13, 237–245.)

The current study examines whether the Homophone Meaning Generation Test (HMGT; Warrington, 2000) is correlated with the phonemic and/or the semantic fluency tests and compares its association with the number of switches and clusters and the mean cluster size of these two tasks. One hundred healthy Hebrew speakers (18–35 years of age; mean = 24.9) generated meanings for 24 homophones and provided words beginning in three different letters, as well as words belonging to three semantic categories. Results show that the HMGT score correlated significantly and similarly with the total score of both the phonemic and the semantic fluency tests. There was a significant correlation between the HMGT and the number of phonemic switches and clusters, but not between the HMGT and the mean phonemic cluster size. The HMGT correlated with the number of semantic switches and clusters, as well as with the mean semantic cluster size. The findings suggest that the relationship between these tests is mediated by a shared executive component, attesting to the HMGT's utility in tapping into mechanisms of shifting and mental flexibility. (JINS, 2007, 13, 424–432.)

Many rehabilitation protocols following traumatic brain injury (TBI) utilize reinforcement and reward to influence behavior and facilitate recovery; however, previous studies suggest survivors of severe TBI demonstrate impairments in contingency utilization and sensitivity. The precise neurobiological mechanisms underlying these deficits have not been thoroughly explored, but can be examined using the “feedback-related negativity” (FRN)— an event-related potential (ERP) component evoked following performance or response feedback (e.g., whether a monetary reward is obtained) with a larger FRN following unfavorable than favorable outcomes—particularly when unfavorable feedback occurs in the context of high reward probability. We examined ERPs elicited by favorable (monetary gain: “reward”) and unfavorable (no monetary gain: “non-reward”) feedback during a guessing task where probability of reward outcome was manipulated in survivors of severe TBI and demographically matched healthy participants. Consistent with previous findings, controls showed larger amplitude FRN to non-reward feedback and the largest amplitude FRN following a non-reward when reward probability context was greatest. In contrast, FRN in TBI participants did not significantly differentiate non-reward from reward trials and their FRN was largest to reward trials in the low reward probability context. Findings implicate an electrophysiological marker of impaired reward context sensitivity following severe TBI. (JINS, 2007, 13, 615–625.)

Sensitive measures of neuropsychological function were adapted to a telephone administration format for use in a large survey of quality of life in breast cancer survivors (BCS). Healthy controls (HC) and BCS were recruited from the community and administered the same neuropsychological test battery on two occasions separated by 1 week. Subjects were randomly assigned to conditions, stratified by diagnosis: In-person at Time-1 and In-person at Time-2 (P-P); Telephone at Time-1 and Telephone at Time-2 (T-T); T-P; and P-T. Four cognitive (Rey Auditory Verbal Learning Test, Controlled Oral Word Association, Digit Span, Symbol Digit) and two self-report measures (Squire Memory Self-Report Scale, Center for Epidemiological Studies Depression Scale) were used. The 106 subjects were randomized (54 HC and 52 BCS). Test–retest reliabilities (intraclass correlations) did not differ significantly by condition across the cognitive or self-report measures and ranged from moderate to near perfect (r's .43–.93; p's < .05). Mean scores at Time-1, practice effects (Time-1 to Time-2), and standard errors of measurement were comparable between In-person and Telephone administration formats. Results suggest that memory, attention, information processing speed, verbal fluency, and self-report of mood and memory can be measured reliably and precisely over the telephone. (JINS, 2007, 13, 799–806.)

Working memory (WM) and inhibitory control (IC) are general-purpose resources that guide cognition and behavior. In this study, the developmental relations between WM and IC were investigated in 96 typically developing children aged 6 to 17 years in an experimental task paradigm using an efficiency metric that combined speed and accuracy performance. The ability to activate and process information in WM showed protracted age-related growth. Performance involving WM and IC together was empirically distinguishable from that involving WM alone. The results indicate that developmental improvements in WM are attributable to increased processing efficiency in activation, suppression, and strategic resource deployment, and that WM and IC are best studied in novel, complex situations that elicit competition among those resources (JINS, 2007, 13, 59–67.)

To date, minimal research has investigated the effect of combining dexamphetamine with standard naming therapy after stroke. The present study used a double-blind, placebo-controlled, multiple baseline, crossover design with two individuals in the chronic stage of stroke recovery. Each individual attended two 4-week blocks of naming therapy (two to three treatment sessions per week). Dexamphetamine (10 mg) was administered at the start of each session during one therapy block, while a placebo was administered during the other therapy block. Therapy progress on treated and untreated items was assessed by a confrontation naming task during and after each therapy block. Both individuals showed greater progress in therapy and maintenance of therapy gains when behavioral treatment was combined with dexamphetamine rather than placebo, although this gain was only statistically significant in one individual. There was no significant improvement on a control task (nonword reading) in either individual. The results provide preliminary evidence that dexamphetamine paired with combined semantic and phonological therapy may be beneficial for the treatment of naming disorders in chronic aphasia. (JINS, 2007, 13, 972–979.)

We investigated the psychometric properties of the random number generation (RNG) task in four studies using a mixed sample of young adults (n = 306), middle-aged adults (n = 40), and patients diagnosed with schizophrenia (n = 26). Data in study 1 were best accounted for by a three-factor solution representing inhibition of stereotypical schemas (seriation), output inhibition (repetition), and monitoring of previous output (cycling). Modest test-retest correlations were found, with the seriation factor showing acceptable stability across time (study 2). In study 3, RNG task performance was related to scores on concurrent neurocognitive tasks to establish construct validity. RNG scores correlated with healthy controls' performance on the Stroop color-word test and patients diagnosed with schizophrenia with executive dysfunctions. Patients diagnosed with schizophrenia performed poorer on the seriation factor of the RNG than healthy control participants (study 4). Our results indicate that the RNG task has modest to acceptable psychometric properties. It primarily taps executive subfunctions (i.e., inhibition, updating, and monitoring), which are affected by psychopathological or neurological deficits. (JINS, 2007, 13, 626–634.)

Deep brain stimulation (DBS) has the potential to significantly reduce motor symptoms in advanced Parkinson's disease (PD). Controversy remains about non-motor effects of DBS and the relative advantages of treatment at two brain targets, the globus pallidus internus (GPi) and the subthalamic nucleus (STN). We investigated effects of DBS on neuropsychological functioning in 42 patients with advanced PD randomly assigned to receive staged bilateral DBS surgery of either the GPi or STN. Patients underwent neuropsychological assessment prior to and 6 months after unilateral surgery. Twenty-nine subsequently underwent surgery to the contralateral side and completed a second follow-up neuropsychological evaluation 15 months later. Unilateral treatment resulted in small but statistically significant reductions in performance on several measures, including verbal fluency and working memory. A similar pattern was observed after bilateral treatment. Reductions in verbal associative fluency were significant only after left-sided treatment. There were few significant differences related to treatment at the two surgical targets. Supplementary analyses suggested that decrements in select neuropsychological domains following DBS are unrelated to age or post-surgical reduction in dopaminergic medication dose. Findings are discussed with reference to possible causes of neuropsychological decline and the need for further controlled studies of specific neuropsychological effects of DBS. (JINS, 2007, 13, 68–79.)

In adults, studies examining the long-lasting cognitive effects of marijuana use demonstrate subtle deficits in attention, executive function, and memory. Because neuromaturation continues through adolescence, these results cannot necessarily generalize to adolescent marijuana users. The goal of this study was to examine neuropsychological functioning in abstinent marijuana using and demographically similar control adolescents. Data were collected from 65 adolescent marijuana users (n = 31, 26% females) and controls (n = 34, 26% females) 16–18 years of age. Extensive exclusionary criteria included independent psychiatric, medical, and neurologic disorders. Neuropsychological assessments were conducted after > 23 days of monitored abstinence. After controlling for lifetime alcohol use and depressive symptoms, adolescent marijuana users demonstrated slower psychomotor speed (p < .05), and poorer complex attention (p < .04), story memory (p < .04), and planning and sequencing ability (p < .001) compared with controls. Post hoc analysis revealed that the number of lifetime marijuana use episodes was associated with poorer cognitive function, even after controlling for lifetime alcohol use. The general pattern of results suggested that, even after a month of monitored abstinence, adolescent marijuana users demonstrate subtle neuropsychological deficits compared with nonusers. It is possible that frequent marijuana use during adolescence may negatively influence neuromaturation and cognitive development. (JINS, 2007, 13, 807–820.)

Motor and gestural skills of children with autism spectrum disorders (ASD), developmental coordination disorder (DCD), and/or attention deficit hyperactivity disorder (ADHD) were investigated. A total of 49 children with ASD, 46 children with DCD, 38 children with DCD+ADHD, 27 children with ADHD, and 78 typically developing control children participated. Motor skills were assessed with the Bruininks–Oseretsky Test of Motor Proficiency Short Form, and gestural skills were assessed using a test that required children to produce meaningful gestures to command and imitation. Children with ASD, DCD, and DCD+ADHD were significantly impaired on motor coordination skills; however, only children with ASD showed a generalized impairment in gestural performance. Examination of types of gestural errors revealed that children with ASD made significantly more incorrect action and orientation errors to command, and significantly more orientation and distortion errors to imitation than children with DCD, DCD+ADHD, ADHD, and typically developing control children. These findings suggest that gestural impairments displayed by the children with ASD were not solely attributable to deficits in motor coordination skills. (JINS, 2007, 13, 246–256.)

There are recent reports that alexithymia may be associated with brain dysfunction involving frontal lobes or right hemisphere regions. However, little is known about the relationship between alexithymia and cognitive deficits in Parkinson's disease (PD). The authors investigated the neuropsychological correlates of alexithymia in a population of 70 nondemented PD patients and 70 controls. Alexithymia was screened using the 20-item version of the Toronto Alexithymia Scale (TAS-20). Standardized scales that measure verbal episodic memory, executive functions, abstract reasoning, and visual–spatial and language abilities were adopted. PD patients with alexithymia performed worse than both PD patients without alexithymia and controls with or without alexithymia on tasks requiring visual–spatial processing. Moreover, regression analyses showed that, in PD patients, but not in controls, poor performance on a constructional praxis task predicted high scores on the TAS-20 subscale, which assesses difficulty in identifying emotions. These data evidence an association between alexithymia and visual–spatial processing alterations in PD patients, supporting the view that the right hemisphere could be specifically involved in the modulation of some facets of alexithymia. (JINS, 2007, 13, 980–992.)

Despite the many studies examining linguistic deterioration in Alzheimer's disease (AD), very little is known about changes in verbal expression during the preclinical phase of this disease. The objective of this study was to determine whether changes in verbal expression occur in the preclinical phase of AD. The sample consisted of 40 healthy Spanish speakers from Antioquia, Colombia. A total of 19 were carriers of the E280A mutation in the Presenilin 1 gene, and 21 were noncarrier family members. The two groups were similar in age and education. All the participants were shown the Cookie Theft Picture Card from the Boston Diagnostic Aphasia Examination and were asked to describe the scene. Specific grammatical and semantic variables were evaluated. The performance of each group was compared using multivariate analyses of the variance for semantic and grammatical variables, and errors. Carriers of the mutation produced fewer semantic categories than noncarriers. In the preclinical phase of AD, changes in verbal expression are apparent and early detection of these differences may assist the early diagnosis of and intervention in this disease. (JINS, 2007, 13, 433–439.)

Cognitive reserve among highly intelligent older individuals makes detection of early Alzheimer's disease (AD) difficult. We tested the hypothesis that mild memory impairment determined by IQ-adjusted norms is associated with single photon emission computed tomography (SPECT) perfusion abnormality at baseline and predictive of future decline. Twenty-three subjects with a Clinical Dementia Rating (CDR) score of 0, were reclassified after scores were adjusted for IQ into two groups, 10 as having mild memory impairments for ability (IQ-MI) and 13 as memory-normal (IQ-MN). Subjects underwent cognitive and functional assessments at baseline and annual follow-up for 3 years. Perfusion SPECT was acquired at baseline. At follow-up, the IQ-MI subjects demonstrated decline in memory, visuospatial processing, and phonemic fluency, and 6 of 10 had progressed to a CDR of 0.5, while the IQ-MN subjects did not show decline. The IQ-MI group had significantly lower perfusion than the IQ-MN group in parietal/precuneus, temporal, and opercular frontal regions. In contrast, higher perfusion was observed in IQ-MI compared with IQ-MN in the left medial frontal and rostral anterior cingulate regions. IQ-adjusted memory impairment in individuals with high cognitive reserve is associated with baseline SPECT abnormality in a pattern consistent with prodromal AD and predicts subsequent cognitive and functional decline. (JINS, 2007, 13, 821–831.)

All object-related actions are complex. Even the “simplest” of reach to grasp movements requires finely honed coordination of the muscles of the arm, hand, and fingers; is dependent upon exquisitely tuned feedforward and feedback mechanisms for motor control; is honed by learning; and is influenced by such cognitive factors as task goals. In this sense, then, the title of this Symposium, Complex Object-Related Actions, contains a redundancy. It is also true, however, that (as compared with, say, memory, language, executive function, attention, and spatial skills) the study of skilled action has been neglected within the fields of neuropsychology and cognitive neuroscience. One reason for this finding may be that many psychologists and neuroscientists do not view action as “cognitive” (Rosenbaum, 2005). As the work presented here illustrates, there is ample recent evidence suggesting that this view is inaccurate. We retain the word “Complex” in the title of the Symposium to emphasize the cognitive, psychological, and memory-related aspects of action that deserve broader interest. We suspect that the organizational principles and mechanisms that underlie cognition in many other domains will be found to play a role in the action system as well.

Forensic neuropsychology studies usually address either cognitive effort or psychological response validity. Whether these are distinct constructs is unclear. In 122 participants evaluated in a compensation-seeking context, the present Exploratory Factor Analysis examined whether forced-choice cognitive effort measures (Victoria Symptom Validity Test, Test of Memory Malingering, Letter Memory Test) and Minnesota Multiphasic Personality Inventory, Second Edition (MMPI-2) validity scales (L, F, K, FBS, Fp, RBS, Md, Dsr2, S) load on independent factors. Regardless of factor rotation strategy (orthogonal or oblique), four response validity factors emerged by means of both Principal Components Analysis (82.7% total variance) and Principal-Axis Factor Analysis (74.1% total variance). The four factors were designated as follows: Factor I, with large loadings from L, K, and S—underreporting of psychological symptoms; Factor II, with large loadings from FBS, RBS, and Md—overreporting of neurotic symptoms; Factor III, with large loadings from VSVT, TOMM, and LMT—insufficient cognitive effort; and Factor IV, with the largest loadings from F, Fp, and Dsr2—overreporting of psychotic/rarely endorsed symptoms. Results reflect the heterogeneity of response validity in forensic samples referred for neuropsychological evaluation. Administration of both cognitive effort measures and psychological validity scales is imperative to accurate forensic neuropsychological assessment. (JINS, 2007, 13, 440–449.)

Candidates for coronary artery bypass graft surgery have been found to exhibit reduced cognitive function prior to surgery. However, little is known regarding the factors that are associated with pre-bypass cognitive function. A battery of neuropsychological tests was administered to a group of patients listed for bypass surgery (n = 109). Medical, sociodemographic and emotional predictors of cognitive function were investigated using structural equation modeling. Medical factors, namely history of hypertension and low ejection fraction, significantly predicted reduced cognitive function, as did several sociodemographic characteristics, namely older age, less education, non-English speaking background, manual occupation, and male gender. One emotional variable, confusion and bewilderment, was also a significant predictor whereas anxiety and depression were not. When significant predictors from the three sets of variables were included in a combined model, three of the five sociodemographic characteristics, namely age, non-English speaking background and occupation, and the two medical factors remained significant. Apart from sociodemographic characteristics, medical factors such as a history of hypertension and low ejection fraction significantly predicted reduced cognitive function in bypass candidates prior to surgery. (JINS, 2007, 13, 257–266.)