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We explored the possible augmenting effect of traumatic brain injury (TBI) history on HIV (human immunodeficiency virus) associated neurocognitive complications. HIV-infected participants with self-reported history of definite TBI were compared to HIV patients without TBI history. Groups were equated for relevant demographic and HIV-associated characteristics. The TBI group evidenced significantly greater deficits in executive functioning and working memory. N-acetylaspartate, a putative marker of neuronal integrity, was significantly lower in the frontal gray matter and basal ganglia brain regions of the TBI group. Together, these results suggest an additional brain impact of TBI over that from HIV alone. One clinical implication is that HIV patients with TBI history may need to be monitored more closely for increased risk of HIV-associated neurocognitive disorder signs or symptoms.

Based upon prior findings with group means, a "prototypical pattern" of neuropsychological results with HIV infection has emerged: impaired executive functioning, motor skills, speed of information processing, and learning, with intact memory retention, most language skills, and visuospatial functioning. We examined neuropsychological results from 553 HIV+ adults to determine the number of patterns seen among individuals with HIV infection. Factor analysis of a relatively comprehensive neuropsychological battery identified 6 component factors: verbal memory (VeM), visual memory (ViM), processing speed (PS), attention/working memory (A/WM), executive function (EF), and motor (M). These factor scores were submitted to hierarchical cluster analysis, to determine the appropriate number of clusters or patterns in the cohort. Final cluster membership was then determined by K-means analysis, based on the Lange, Iverson, Senior, and Chelune (2002) method. A 6-cluster solution was found to be most appropriate. The definitions of the clusters were based upon ipsative scoring of factor scores to indicate relative strengths and weaknesses (independent of overall level of performance): Cluster 1: strong EF; Cluster 2: strong M, weak VeM and EF; Cluster 3: strong PS, weak ViM and EF; Cluster 4: strong VeM, weak M; Cluster 5: strong A/WM; Cluster 6: strong VeM, weak EF. Neuropsychological-impairment rates differed across clusters, but all 6 clusters contained substantial numbers of impaired and unimpaired individuals. Cluster membership was not explained by demographic variables or psychiatric or neuromedical confounds. Thus, there does not appear to be a single, prototypical pattern of neuropsychological impairment associated with HIV infection for this battery of representative neuropsychological tests.

The California Verbal Learning Test (CVLT) is designed to quantify components of verbal learning, retention and retrieval. The present study used multiple regression analyses to correct for demographic characteristics on CVLT performance measures. There were 906 subjects, of whom 549 were Caucasians (61%) and 357 were African Americans (39%). Age, education, ethnicity, and gender were found to be significant predictors of performance on several CVLT indices, including Total Words Recalled, Trial 1, Trial 5, List B, Short Delay Free Recall (SDFR), and Long Delay Free Recall (LDFR). Demographically corrected T-scores were calculated for a base sample of 672 subjects and cross-validated on 234 separate subjects. Tables and regression equations are offered to convert raw scores into T-scores corrected for age, gender, education, and ethnicity. Demographically corrected Recognition Discriminability cutoff scores were calculated for age and education levels. In order to provide some indices of important memory processes, we also computed indices of retrieval, Short-Delay forgetting and Long-Delay forgetting and present normative information for them.

Regression-based norms for the Trail Making Test, Boston Naming Test, and Wisconsin Card Sorting Test, which we published in 1991 and 1993, have been criticized by Fastenau (1998) as having overcorrected for demographic influences in a sample of 63 older adults. We present data from new, independent participant samples that are consistent with expectations from the regression-based norms. We propose that Fastenau's findings in this instance resulted from the nonrepresentative nature of his relatively small sample, rather than from statistical deficiencies of regression based norms. Our currently published norms on one of the four tests considered here, the Boston Naming Test, are based upon a participant sample that was small and had inadequate representation of young adults. We address this by providing updated norms based on a much larger and more representative sample (N = 531).

Patterns of memory performance were examined for 9 participants with HIV-associated dementia (HAD), 15 HIV-seropositive participants without dementia, and 15 HIV-seronegative controls. Episodic and semantic memory were assessed using the California Verbal Learning Test, the Boston Naming Test, and Verbal Fluency tests. The HAD group showed deficits in episodic memory, with relative sparing of semantic memory. In addition, results suggest a retrieval deficit in HAD rather than a deficit in retention of information. This pattern is consistent with the presence of a subcortical dementing process and supports findings from previous neuropathological, neuroimaging, and neuropsychological studies suggesting that subcortical brain dysfunction is frequently associated with HIV disease (e.g., Navia, Jordan, & Price, 1986).

The four neurological patient groups and the normals from the Wisconsin Card Sorting Test (WCST) standardization sample were used to examine the discriminability of the WCST's indices. Results reveal consistent differentiation of normals from the patient groups on all WCST variables, with classification rates averaging 71% accuracy. However, patient groups with frontal, diffuse, and nonfrontal lesions were not consistently discriminable from each other. The results suggest that the WCST is most usefully conceptualized as a measure of executive abilities that involves the frontal lobes, but should not be considered solely as a marker of isolated frontal lobe pathology.

The evaluation of current level of neuropsychological functioning is handicapped by the lack of validated actuarial methods for estimating premorbid intellectual functioning. The present study cross-validated and attempted to improve the one existing method of using demographic variables in a systematic way to predict WAIS Full Scale IQ (Wilson et al., 1978). A sample of 491 neurologically normal subjects was used. The results generally supported the IQ prediction equation, but did reveal systematic differences in accuracy of prediction and direction of prediction error for IQs in the high and low ranges. Also, a simpler IQ prediction formula that uses only years of education was developed and compared with the 5-variable Wilson et al. formula.

Three hundred and three patients with chronic obstructive pulmonary disease and concomitant neuropsychological impairment plus 99 healthy control subjects matched on the basis of socio-demographic variables were administered an expanded version of the Halstead-Reitan Battery and a battery of instruments measuring the quality of everyday-life functioning. The results indicated that neuropsychological measures can be used to predict everyday-life functioning in impaired persons, but few significant relationships were observed in the normals. Neuropsychological status was more consistently related to activities of daily living and basic social role performance than to emotional status. Complex, multifunctional neuropsychological tasks were found to be the best overall predictors of life functioning, whereas more specific tasks served as better predictors of specific dimensions of life functioning.

This study used the Peabody Individual Achievement Test (PIAT) to assess reading and spelling skills in a normal control group (n = 100) and in patients having cerebral damage in the left hemisphere (LH; n = 86) or right hemisphere (RH; n = 76). Relative to the normals, both brain-damaged groups were impaired on PIAT Reading Comprehension and Spelling. Only the LH group was impaired on PIAT Reading Recognition. PIAT performances were strongly related to extent of brain damage within the left hemisphere, but not within the right. Similarly, whereas reading and spelling deficits were associated with temporal- and occipital-lobe involvement in the LH group, presence or absence of specific lobe involvement was unrelated to PIAT performance in the RH group. Relationships also were assessed between PIAT performances and demographic variables and the Average Impairment Rating from the Halstead-Reitan Battery.

This study assessed the diagnostic utility of the Seashore Tonal Memory Test in detecting and localizing cerebral lesions. A group of 238 subjects with focal or diffuse cerebral lesions and a group of 112 normal comparison subjects were administered the Seashore Tonal Memory Test and the Halstead-Reitan Battery. All brain-damaged subgroups did significantly worse than the normal group on the Tonal Memory Test. Patients with right-hemisphere lesions were more impaired on this test than were those with left-hemisphere lesions. In contrast, Seashore Rhythm Test scores were not significantly different for groups with right- versus left-hemisphere lesions. Tonal Memory performance was not found to be related to more precise location of structural lesions within the right hemisphere. Step-wise discriminate function analyses indicated that the Tonal Memory Test adds to the Halstead-Reitan Battery in discriminating left-hemisphere from right-hemisphere lesions and that, for this purpose, it was a better discriminator than all but one of the individual tests currently in the battery.

Forty-one patients with putative Alzheimer's Disease (AD) were evaluated to determine the diagnostic utility of a profile of Wechsler Adult Intelligence Scale (WAIS) subtests which has been proposed by Fuld (1984) to identify cholinergic dysfunction. Only nine (21.9%) of these patients had positive Wechsler profiles. Half (n = 21) of the AD patients had been given the WAIS, and the other half (n = 20) the Wechsler Adult Intelligence Scale-Revised (WAIS-R). Positive profiles occurred more often in the AD subgroup given the WAIS-R, but this difference was not statistically significant. Specificity of the formula was evaluated using Wechsler results of 42 older normals and 30 patients who were being evaluated for dementia but who did not have AD. One of the 42 normals (2.4%) and five of the patient controls (16.7%) showed a positive Wechsler profile. Because of the Fuld formula's low sensitivity, a negative Wechsler profile cannot be used to help rule out AD. Although specificity of the formula is high, the diagnostic value of a positive Wechsler profile is modest even under the most favorable AD baserate conditions.

A newly developed T score conversion system that corrects Wechsler Adult Intelligence Scale (WAIS) and Wechsler Adult Intelligence Scale-Revised (WAIS-R) subtest and IQ scores for appropriate demographic variables was used to compare subjects' performance on the two versions of the instrument. Using 428 pairs of subjects matched on age, education, and sex, with one person in each pair having taken the WAIS and the other the WAIS-R, we found no significant differences in level or pattern of performance when analyses were performed on the T scores. This was in contrast to highly significant differences when uncorrected scaled scores and IQ values were compared. Therefore, the T score system appears to provide a tool which may help clinicians make more direct comparisons between the results obtained on the WAIS and WAIS-R.