The strength and nature of the association between IQ and performance on other cognitive tests has both practical and conceptual significance for clinical neuropsychology. In this study, 28 measures derived from 16 cognitive tests were analyzed as a function of IQ in 221 adults. Participants were grouped by their IQ scores as having below average (BA), average (A), or above average (AA) intelligence. Planned comparisons revealed that A adults performed significantly better than BA adults on 25 of the 28 cognitive measures, and that AA adults performed significantly better than A adults on 19 of 28 measures. Effect sizes averaged .74 for BA–A comparisons and .41 for A–AA comparisons. Linear, quadratic, and cubic functions described the relationships between IQ and cognitive test performance equally well for most individual test measures and for a composite index of test performance, whereas quadratic and cubic functions explained the proportion of abnormal performances better than a linear function. These findings confirm that IQ predicts concurrent neuropsychological performance across the entire spectrum of intelligence, but more so among persons of average IQ or less than among those with above average IQ. (JINS, 2004, 10, 82–90.)

Few follow-up studies of children with very low birth weight (VLBW, <1,500 g) have examined neuropsychological sequelae at later ages or neonatal risks as predictors of these outcomes. The present study assessed cognitive skills at mean age 16 years in 48 participants with <750 g birth weight, 47 with 750–1,499 g birth weight, and 52 term-born controls. Our major objectives were to delineate the long-term cognitive consequences of VLBW, and to determine if risks for periventricular brain insults accounted for variations in outcomes. Analysis revealed poorer outcomes for the <750 g group than for term-born controls on nearly all measures, with specific impairments in visual–motor skills, spatial memory, and executive function. Predictors of outcome for participants with VLBW included lower birth weight, lower weight for gestational age, and a longer period of oxygen requirement for chronic lung disease. The longer-term consequences of VLBW are consistent with expectations based on early brain pathology and suggest limitations to functional plasticity. (JINS, 2004, 10, 987–1004.)

Researchers and clinicians using Jacobson and Truax's index to assess the reliability of change in patients, or its counterpart by Chelune et al., which takes practice effects into account, are confused by the different ways of calculating the standard error encountered in the literature (see the discussion started in this journal by Hinton-Bayre). This article compares the characteristics of (1) the standard error used by Jacobson and Truax, (2) the standard error of difference scores used by Temkin et al. and (3) an adaptation of Jacobson and Truax's approach that accounts for difference between initial and final variance. It is theoretically demonstrated that the last variant is preferable, which is corroborated by real data. (JINS, 2004, 10, 888–893.)

The present study examined dual-task performance in elders with cognitive impairments and normal controls. The participants (N = 60; M age = 84.6) were recruited from residential facilities and the community. They were assigned to one of three groups: (1) cognitive impairment; (2) residential facility control; (3) community control. Two different dual-task conditions were comprised of simple tests that are presumably processed via separate perceptual modalities: 1 visual–manual and 1 auditory–verbal. The first condition consisted of a visual cancellation test and an auditory digit span. The second condition was comprised of an alternate form of the visual cancellation test and letter fluency. MANOVA examined the effect of cognitive status (3-level independent variable) on 3 indices of dual-task performance (letter fluency, digit span, visual cancellation). Analyses controlled for age, education and performance on each test when performed alone. The results revealed that the cognitive impairment group incurred significantly greater dual-task costs compared to both control groups. Furthermore, as was evident from discriminant function analyses, the dual-task measures were very accurate and better than the traditional neuropsychological measures at discriminating elders with cognitive impairments from normal controls. (JINS, 2004, 10, 230–238.)

The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery was developed to evaluate cognitive impairments associated with Alzheimer's disease (AD). Previous studies have suggested that the battery is multi-dimensional, represented by either 3 or 5 dimensions. In this study a principal factor analysis was conducted using contemporary quantitative methods for determining the number of factors. Exploratory factor analysis of the CERAD battery and MMSE was conducted using one-half of the CERAD database (total N = 969). Glorfeld's modification of Horn's parallel analysis method suggested that there was 1 common factor in the variable matrix. Characterization of patterns of deficits in AD requires supplementation of measures derived from the CERAD and MMSE with other tests. (JINS, 2004, 10, 559–565.)

Traumatic brain injury (TBI) is often associated with enduring impairments in high-level cognitive functioning, including working memory (WM). We examined WM function in predominantly chronic patients with mild, moderate and severe TBI and healthy comparison subjects behaviorally and, in a small subset of moderate-to-severe TBI patients, with event-related functional magnetic resonance imaging (fMRI), using a visual n-back task that parametrically varied WM load. TBI patients showed severity-dependent and load-related WM deficits in performance accuracy, but not reaction time. Performance of mild TBI patients did not differ from controls; patients with moderate and severe TBI were impaired, relative to controls and mild TBI patients, but only at higher WM-load levels. fMRI results show that TBI patients exhibit altered patterns of activation in a number of WM-related brain regions, including the dorsolateral prefrontal cortex and Broca's area. Examination of the pattern of behavioral responding and the temporal course of activations suggests that WM deficits in moderate-to-severe TBI are due to associative or strategic aspects of WM, and not impairments in active maintenance of stimulus representations. Overall, results demonstrate that individuals with moderate-to-severe TBI exhibit WM deficits that are associated with dysfunction within a distributed network of brain regions that support verbally mediated WM. (JINS, 2004, 10, 724–741.)

The internal consistency and convergent and discriminant validity of the d2 Test, a cancellation test of attention and concentration, was examined in a sample of 364 U.S. adults. Test-taking strategy, new process scores for assessing performance constancy, and relations to gender and education were explored. Results suggested that the d2 Test is an internally consistent and valid measure of visual scanning accuracy and speed. Overall performance scores were related to a proxy measure of test-taking strategy in the expected direction, and new acceleration and deterioration measures exhibited convergent validity. Suggested directions for future research include discrimination of attentional processes that support immediate and sustained visual scanning accuracy and speed, further examination of the impact of test-taking strategies on overall performance measures, and additional construct validity examinations for the new process measures. (JINS, 2004, 10, 392–400.)

We examined the possible role of autonomic activity in Huntington's disease (HD) during a risky decision making task. Skin conductance responses (SCRs) of 15 HD participants and 16 healthy controls were measured while they performed a computerized version of the Simulated Gambling Task (SGT). The results replicated our previous finding of a performance decrement in HD, and showed that HD was associated with an altered pattern of SCRs during the risky decision task. Specifically, the healthy controls produced increased SCRs following selections from the disadvantageous decks and following losing selections. In contrast, the SCRs of the HD group did not differentiate between wins and losses. These findings indicate a reduced impact of loss on decision-making processes under risky conditions in HD. (JINS, 2004, 10, 239–245.)

Verbal learning and memory (VLM) following pediatric stroke was characterized in a cross-sectional neuropsychological and neuroimaging study of 26 subjects, aged 5 to 17, with a history of pediatric stroke and 26 age, SES, and gender matched orthopedic controls. Further comparisons were made between the VLM profiles of stroke subjects with right versus left hemisphere lesions and early (≤12 months) versus late (>12 months) strokes. Overall, stroke subjects scored significantly lower than control subjects on several VLM indices (California Verbal Learning Test–Children; CVLT–C), as well as on measures of intellectual functioning (IQ) and auditory attention/working memory (Digit Span). Subgroup analyses of the stroke population found no significant differences in VLM, Digit Span, Verbal IQ or Performance IQ when left-hemisphere lesion subjects were compared to right-hemisphere lesion subjects. In contrast, early strokes were associated with significantly fewer words recalled after delay, reduced discriminability (fewer correct hits relative to false positive errors on recognition testing), and relatively worse auditory attention/working memory scores (Digit Span). These findings indicate that pediatric stroke subjects demonstrated more VLM impairment than control subjects, and early strokes were associated with greater recall and recognition deficits. In stark contrast with adult-onset stroke, both left- and right-hemisphere lesions during childhood resulted in similar VLM performance. (JINS, 2004, 10, 742–752.)

Acute Respiratory Distress Syndrome (ARDS) is characterized by lung injury and hypoxemia, has a high mortality rate, and is associated with significant morbidity including cognitive and emotional sequelae and decreased quality of life. There is limited information regarding which of these factors are associated with decreased quality of life. This study assessed the relationships between quality of life, cognitive and emotional function in ARDS survivors at 1-year post-hospital discharge. Sixty-six ARDS survivors were administered a battery of neuropsychological tests, measures of emotional function and quality of life 1 year post-hospital discharge. At 1 year 45% of the ARDS patients had cognitive sequelae and 29% had mild to moderate symptoms of depression and anxiety. Depression, anxiety, and intensive care unit length of stay were significantly correlated with decreased quality of life. Cognitive impairments did not correlate with decreased quality of life. Illness severity and emotional function, but not cognitive sequelae, are associated with decreased quality of life 1 year following ARDS. ARDS is common and may result in significant cognitive and emotional morbidity and decreased quality of life. (JINS, 2004, 10, 1005–1017.)

The present study examined the influence of African American acculturation on the performance of neuropsychological tests following traumatic brain injury (TBI). Seventy one participants already enrolled in a larger-scale study assessing the impact of TBI (i.e., the South Eastern Michigan Traumatic Brain Injury Model Systems project) completed a self-report measure of African American acculturation (African American Acculturation Scale–Short Form; Landrine & Klonoff, 1995) in addition to a standardized battery of neuropsychological tests. Hierarchical regression analyses were conducted to evaluate the relationship between level of acculturation and test performance after controlling for injury-related (initial Glasgow Coma Scale score, time since injury) and demographic variables (age, sex, years of education, and socioeconomic status). Lower levels of acculturation were associated with significantly poorer performances on the Galveston Orientation & Amnesia Test, MAE Tokens test, WAIS–R Block Design, Rey Auditory Verbal Learning Test, and Symbol Digit Modalities Test. Decreased levels of acculturation were also significantly related to lower scores on a composite indicator of overall neuropsychological test performance. In addition, the examiner's ethnicity (Black or White) was related with scores on a few of the tests (i.e., Block Design, Trail Making Test), but was not significantly associated with the overall neuropsychological test performance. Overall, these findings suggest that differences in cultural experience may be an important factor in the neuropsychological assessment of African Americans following TBI, and provide additional support for the hypothesis that cultural factors may partially account for the differences among ethnic/cultural groups on neuropsychological tests. (JINS, 2004, 10, 566–577.)

It is important to preface this piece by advising the reader that the author is not writing from the point of view of a statistician, but rather that of a user of reliable change. The author was invited to comment following the publication of an original inquiry concerning Reliable Change Index (RCI) formulae (Hinton-Bayre, 2000) and after acting as a reviewer for the current Maassen paper (this issue, pp. 888–893). Having been a bystander in the development of various RCI methods, this comment serves to represent the struggle of a non-statistician to understand the relevant statistical issues and apply them to clinical decisions. When I first stumbled across the ‘classical’ RCI attributed to Jacobson and Truax (1991) (Maassen, this issue, Equation 4), I was quite excited and immediately applied the formula to my own data (Hinton-Bayre et al., 1999). Later, upon reading the Temkin et al. (1999) paper I commented on what seemed to be an inconsistency in their calculation of the error term (Hinton-Bayre, 2000). My “confusion” as Maassen suggests was derived from the fact that I noted the error term used was based on the standard deviation of the difference scores (Maassen, Expression 5*) rather than the Jacobson and Truax formula (Maassen, Expression 4). This apparent anomaly was subsequently addressed when Temkin et al. (2000) explained they had employed the error term proposed by Christensen and Mendoza (1986) (Maassen, Expression 5). My concern with the Maassen manuscript was that it initially appeared two separate values could be derived through using expressions 5 and 5* using the Temkin et al. (1999) data. This suggested there might be four (expressions 4, 5, 5*, and 6), rather than three, ways to calculate the reliable change error term based on a null hypothesis model. Once again I was confused. Only very recently did I discover that expressions 5 and 5* yield identical results when applied to the same data set (N.R. Temkin, personal communication) and when estimated variances are used (G. Maassen, personal communication). The reason for expressions 5 and 5* yielding slightly different error term values using the Temkin et al. (1999) data was due to use of nonidentical samples for parameter estimation. The use of non-identical samples came to light in the review process of the present Maassen paper—which Maassen now indicates in an author's note. Thus there were indeed only three approaches to consider (Expressions 4, 5, & 6). Nonetheless, Maassen maintains (personal communication) that Expression 5, as elaborated by Christensen and Mendoza (1986), represents random errors comprising the error distribution of a given person, whereas Expression 5* refers to the error distribution of a given sample. While it seems clear on the surface that the expressions represent separate statistical entities, it remains unclear to the present author how these expressions can then yield identical values when applied to test–retest data derived from a single normative group. Unfortunately however, my confusion does not stop there.

Shape and letter cancellation test performance was investigated among large samples of African American, Hispanic, and White non-demented elders. Ethnic minority elders took significantly longer to complete both tasks compared to Whites. An index of task efficiency, which simultaneously measures time and accuracy, suggested that slower time by minority elders was not related to a measurable effort to achieve greater accuracy. The frequency of commission errors was greater in our sample than in previous reports, especially among ethnic minority elders. Although significant differences were observed between the ethnic groups when matched for years of education, equating for literacy level eliminated all performance differences between African Americans and Whites on both cancellation tasks. (JINS, 2004, 10, 401–411.)

Impairment in delayed recall has traditionally been considered a hallmark feature of Alzheimer's disease (AD). However, vulnerability to semantic interference may reflect early manifestations of the disorder. In this study, 26 mildly demented AD patients (mild AD), 53 patients with mild cognitive impairment without dementia (MCI), and 53 normal community-dwelling elders were first presented 10 common objects that were recalled over 3 learning trials. Subjects were then presented 10 new semantically related objects followed by recall for the original targets. After controlling for the degree of overall memory impairment, mild AD patients demonstrated greater proactive but equivalent retroactive interference relative to MCI patients. Normal elderly subjects exhibited the least amount of proactive and retroactive interference effects. Recall for targets susceptible to proactive interference correctly classified 81.3% of MCI patients and 81.3% of normal elderly subjects, outperforming measures of delayed recall and rate of forgetting. Adding recognition memory scores to the model enhanced both sensitivity (84.6%) and specificity (88.5%). A combination of proactive and retroactive interference measures yielded sensitivity of 84.6% and specificity of 96.2% in differentiating mild AD patients from normal older adults. Susceptibility to proactive semantic interference may be an early cognitive feature of MCI and AD patients presenting for clinical evaluation. (JINS, 2004, 10, 91–100.)

Ipsative approaches to neuropsychological assessment typically involve interpreting difference scores between individual test scores. The utility of these methods is limited by the reliability of neuropsychological difference scores and the number of comparisons between scores. The present study evaluated the utility of difference scores using factor analytic methods, including reliable components analysis (RCA), equally weighted composites and individual neuropsychological measures. Data from 1,364 individuals referred for neuropsychological assessment were factor analyzed and the resulting solutions were used to compute composite scores. Reliabilities and confidence intervals were derived for each method. Results indicated that RCA outperformed other factor analytic methods, but produced a slightly different factor structure. Difference scores derived using orthogonal solutions were slightly more reliable than oblique methods, and both were more reliable than those from equally weighted composites and individual measures. Confidence intervals for difference scores were considerably smaller for factor methods relative to those for individual test comparisons, due to the greater reliability of factor based difference scores and the smaller number of comparisons required. These findings suggest that difference scores derived from orthogonal factor solutions, particularly RCA solutions, may improve reliability for clinical assessment purposes. (JINS, 2004, 10, 578–589.)

Different authors have used different estimates of variability in the denominator of the Reliable Change Index (RCI). Maassen attempts to clarify some of the differences and the assumptions underlying them. In particular he compares the ‘classical’ approach using an estimate SEd supposedly based on measurement error alone with an estimate SDiff based on the variability of observed differences in a population that should have no true change. Maassen concludes that not only is SEd based on classical theory, but it properly estimates variability due to measurement error and practice effect while SDiff overestimates variability by accounting twice for the variability due to practice. Simulations show Maassen to be wrong on both accounts. With an error rate nominally set to 10%, RCI estimates using SDiff wrongly declare change in 10.4% and 9.4% of simulated cases without true change while estimates using SEd wrongly declare change in 17.5% and 12.3% of the simulated cases (p < .000000001 and p < .008, respectively). In the simulation that separates measurement error and practice effects, SEd estimates the variability of change due to measurement error to be .34, when the true variability due to measurement error was .014. Neuropsychologists should not use SEd in the denominator of the RCI. (JINS, 2004, 10, 899–901.)

The social outcomes of pediatric traumatic brain injury (TBI) were examined in a prospective, longitudinal study that included 53 children with severe TBI, 56 with moderate TBI, and 80 with orthopedic injuries, recruited between 6 and 12 years of age. Child and family functioning were assessed at baseline, at 6- and 12-month follow-ups, and at an extended follow-up a mean of 4 years post injury. Growth curve analyses revealed that pediatric TBI yields negative social outcomes that are exacerbated by family environments characterized by lower socioeconomic status, fewer family resources, and poorer family functioning. After controlling for group membership, age, race, socioeconomic status, and IQ, path analyses indicated that long-term social outcomes were accounted for in part by specific neurocognitive skills, including executive functions and pragmatic language, and by social problem-solving. Deficits in these domains among children with TBI are likely to reflect damage to a network of brain regions that have been implicated in social cognition. (JINS, 2004, 10, 412–426.)

In their recent article, Delis et al. (2003) criticized the use of factor analysis for evaluating construct validity. Focusing on a key component of their argument, they reported a high correlation between two memory test scores in a community sample but a low correlation between the same scores in a sample of people with Alzheimer's disease. As a consequence, they argued that the presence of a “dissociation” between the two variables in the Alzheimer's sample contradicted the single-factor result derived from studies of community samples and other clinical groups: “Two variables that share a high degree of variance in normal participants … and thus appear to measure a unitary cognitive construct, can dissociate into two distinct functions, but only in certain homogeneous patient populations” (p. 940).

The ability to measure neuropsychological outcomes in a comparable manner in different cultural groups is important if studies conducted in geographically diverse regions are to advance knowledge of disease effects and moderating influences. The purpose of this study was to evaluate the application of neuropsychological test procedures developed for use in North America and Europe to children in a rural region of Kenya. Our specific aim was to determine if these methods could be adapted to a non-Western culture in a manner that would preserve test reliability and validity. Procedural modifications yielded reliable tests that were sensitive to both the sequelae of cerebral malaria and to children's social and school backgrounds. Results suggest that adaptations of existing tests can be made in such a way as to preserve their utility in measuring the cross-cultural sequelae of childhood neurological diseases. (JINS, 2004, 10, 246–260.)

Major depressive disorder (MDD) and frontotemporal dementia (FTD) are both disorders in elderly populations that involve the prefrontal cortex and appear to have similar neurocognitive deficits. This review examined whether there are testable deficits in cognition that are consistent across individuals within the same neuropathological condition that could be used to facilitate early diagnoses. Medline and PsychInfo databases were searched for cognitive studies of depressed and FTD patients that used a matched control group and reported findings with means and standard deviations (N = 312). Effect sizes for FTD patients with mild and moderately advanced disease were compared to effect sizes within subgroups of depressed patients, such as inpatients, outpatients and community volunteers. Moderately advanced FTD patients were more impaired than depressed patients over all domains, particularly in language ability, although depressed inpatients appeared similar to FTD patients in some domains. Effect sizes for FTD patients who were in the mild, or early, stage of the disease (MMSE = 28) were similar to those of depressed outpatients but slightly worse than those of community volunteers in all domains except semantic memory and executive ability. In the latter two domains, even mild FTD patients had notably large deficits. All FTD patients showed more severe deficits in some domains relative to other domains. In contrast, depressed patients tended to vary by clinical presentation or disease severity, but the magnitude of impairment for each subgroup remained relatively consistent across domains and they did not have the severe focal deficits in one or two domains demonstrated by FTD patients. (JINS, 2004, 10, 753–771.)