Epilepsy, neuropsychological deficits, and EEG lateralization.

One hundred eight epileptic patients (59 men, 49 women; 55% partial seizures, 45% generalized) were examined on 45 indices comprising a modified Halstead Neuropsychological Test Battery. Factor analyses identified five dimensions: Verbal Comprehension, Perceptual Organization, Selective Attention, Motor Skills, Abstract Reasoning. These factors are similar to those previously reported for neurocognitive abilities in several different populations. Relative deficits on Verbal Comprehension and Abstract Reasoning were related, as predicted, to left hemispheric dysfunction as indexed by EEG localization. Perceptual Organization demonstrated a further, predictable relationship to right hemispheric function. Deficits on Selective Attention were not clearly lateralized, being correlated with a wide variety of electroencephalographic abnormalities. The implications of these findings for the use of neurocognitive profiles in treatment planning for this population are discussed.

Trait analyses of the Luria-Nebraska Intellectual Processes, Motor Functions, and Memory Scales.

Trait analyses of the Luria-Nebraska's Intellectual Processes, Motor Functions, and Memory Scales were performed using multitrait-multimethod procedures and confirmatory factor analysis. Three measures each of intellectual, motor, and memory functions were administered to 161 neuropsychiatric patients. Intellectual scales (viz., Luria-Nebraska and WAIS-R) were found to have convincing discriminant properties, but motor and memory measures demonstrated visibly less such robustness. Confirmatory factor analyses supported a three-factor model of the 9 x 9 matrix, in which each of the three Luria-Nebraska scales serves as a marker for the factors. Issues related to the neuropsychological constructs, test construction, and construct validity of measurement procedures employed in clinical neuropsychology are discussed.

Wechsler Verbal-Performance IQ discrepancies among psychiatric inpatients: implications for subtle neuropsychological dysfunctioning.

One hundred seventy-nine psychiatric inpatients were administered the WAIS-R and several neuropsychological and academic achievement tests. All subjects were assigned to three groups based on their WAIS-R's VIQ-PIQ discrepancy scores: (i) Low Verbal (Verbal IQ < Performance IQ. by at least 13 points); (ii) Low Performance (Performance IQ < Verbal IQ by at least 13 points); and (iii) Equal (Verbal IQ-Performance IQ within 13 points). The Low Verbal group made significantly more errors on the Speech Sounds Perception Test, demonstrated lower spelling scores, evinced more aphasic signs, and had had more special education placements than did the Equal or Low Performance groups. The Low Performance subjects demonstrated significantly more signs of constructional dyspraxia and performed more poorly on the Grooved Pegboard test. The neuropsychiatric patients who had Verbal-Performance IQ discrepancies of at least one standard deviation may be at risk for specific, subtle neuropsychological deficits.

Relationships between the WAIS and neuropsychological measures for neuropsychiatric inpatients.

The current study examines the sensitivity of the Wechsler Adult Intelligence Scale in predicting performance on a modified Halstead Neuropsychological Test Battery for lower-functioning neuropsychiatric inpatients (97 men, 54 women). Regression analyses support earlier-reported findings that the WAIS's subtests more accurately predict neuropsychological test performance than do the WAIS IQ's alone. The IQ's and scaled scores respectively predicted 27% and 39% of the variance in the Halstead's measures. The overall relationship between neurocognitive and WAIS indices is somewhat greater than previous reports and is apparently due to the fact that the lower the overall level of cognitive ability, the lower is neuropsychological functioning in general. However, since most of the variance in the modified Halstead Battery was not common with the WAIS's indices, these findings continue to support the practice of including both sets of measures as part of a comprehensive neuropsychological assessment paradigm for such patients. The importance of developing instruments and procedures which more precisely measure "fluid" neurocognitive abilities is underscored.

The effects of unilateral and multifocal lesions on the WAIS-R: a factor analytic study of stroke patients.

An exploratory maximum likelihood factor analysis of the inter-correlations among the 11 subtests of the WAIS-R was undertaken for 167 patients who had a primary diagnoses of cerebrovascular accident (right hemisphere, n = 79; left hemisphere, n = 55; diffuse or multifocal, n = 33). On the WAIS-R, this sample performed below normative standards (average scaled score = 7.1), but demonstrated a pattern of variability among subtests similar to the normative groups. Interestingly, VIQ-PIQ discrepancy analyses revealed V > P profiles for patients with lesions in either or both hemispheres. The best fit for the WAIS-R matrix was an oblique two-factor model comprised of the Verbal and Performance subtests. This factor solution, which was moderately correlated (.52), accounted for 58.8% of the total variance. The stability of a two-factor structure in this neurologic impaired population suggests that the WAIS-R is a robust measure, even when used within such a rehabilitation population. Only two of the eleven subtests (i.e., Comprehension and Picture Arrangement), however, were related to lesion site. Rehabilitation settings may need to rely more on neuropsychological procedures that measure the more "fluid" areas of neurocognitive ability, in contrast to the WAIS-R which appears less sensitive to the neurological impairment associated with stroke.

Estimating pattern similarity for correlation matrices from differing neuropsychiatric populations.

The present example illustrates a method for assessing pattern similarity for correlation matrices from populations known to differ in clinically important respects. The data underlying previously published confirmatory factor analyses of neuropsychological traits are presented in two methods for assessing whether the matrices are similar enough to justify their aggregation into a single composite matrix. The significance of this procedure for research in applied neuropsychology is commented upon in terms of the benefits to model diagnostics.

Factor structure of the Family Environment Scale: effects of social desirability.

Presented for 64 Ss a replication of the Family Environment Scale's maximum likelihood factor structure for which the two-factor, Varimax-rotated solution was found to be stable when the correlations among the subscales were corrected for the effects of social desirability response bias. As reported previously (Fowler, 1981), the first bipolar dimension, "cohesion vs. conflict," measures relationship-centered concerns, while the second bipolar axis "organization-control," reflects basic system-maintenance properties of family activity. These two factors are comparable to others reported in small-group research, parent-child interaction studies, and human communication investigations. A comprehensive statistical model of the Family Environment Scale can be constructed where the semantic space of the 10 subscales reflects the two supraordinate concepts of "interpersonal cohesion" and "control." It is not yet known to what extent the modeling of this impression-space can be expanded to reveal dependencies on imminent (familial and individual) cognitive and personality schemata.

WAIS factor pattern for neuropsychiatric inpatients.

The current study examines the factor pattern of the Wechsler Adult Intelligence Scale for a sample of 151 neuropsychiatric inpatients (97 men, 54 women). As expected, these patients performed less well on all 11 of the subtests and ranged from .60 to 1.54 SD below normative standards. These patients were neither more variable nor were the intercorrelations among the subtests lower than those of the normative group. As in previous research, maximum likelihood factor analyses revealed the presence of a Verbal Comprehension dimension and a Perceptual Organization dimension, factors that were moderately correlated (.60). The stability of a two-factor solution for the WAIS in this population and its implications for the inclusion of the WAIS as a component of a neuropsychological assessment paradigm are discussed.

A multifactor model of the Halstead-Reitan Neuropsychological Test Battery and its relationship to cognitive status and psychiatric diagnosis.

An oblique, five-factor model of a modified Halstead-Reitan Neuropsychological Test Battery is presented. One hundred fifty-one neuropsychiatric inpatients (94 men, 57 women) were examined on 44 neuropsychological indices. Five correlated dimensions (r = .25), viz., Verbal Comprehension, Perceptual Organization, Sensory-attention, Primary Motor, and Tactile-spatial abilities, were identified by maximum likelihood factor analyses of this correlation matrix. These findings are quite similar to those reported earlier by Fowler, Richards, Berent, and Boll (1985, 1987) and Royce, Yeudall, and Bock (1976). The factors may be broadly categorized using the distinction made by Lezak (1983) for verbal, nonverbal, and mental activity variables. MANOVAs revealed systematic relationships between simple-weighted factor scores and: (1) the overall level of cognitive functioning (p less than .01), as well as (2) psychiatric diagnosis (p less than .01). Implications of these findings for understanding the impact of neuropsychiatric disorders on the structure of abilities for such patients are developed.

WAIS-R factor and performance on the Luria-Nebraska's Intelligence, Memory, and Motor Scales: a canonical model of relationships.

The pattern and level of performance on the WAIS-R and the Luria-Nebraska's Intelligence, Memory, and Motor Scales were examined for 93 neurologically impaired adults. Maximum likelihood factor analyses of the WAIS-R indicated the presence of strongly correlated (.72) Verbal Comprehension and Perceptual Organization dimensions. Comparisons of these factors to those of the standardization group revealed an acceptable level of similarity (.94) for Verbal Comprehension, but not for Perceptual Organization (.53). Canonical correlations between WAIS-R factor scores and the three Luria-Nebraska scaled scores accounted for 82% of the total variance. Each set of procedures evidently is indexing the same theoretical constructs. Implications of these findings for our understanding of the measurement models that underlie clinical neuropsychology are discussed.

Confirmatory factor analytic models of the WAIS-R for neuropsychiatric patients.

Five multifactor models, in both orthogonal and oblique versions, and a single-factor model of the WAIS-R's factor pattern were examined by confirmatory maximum likelihood factor analyses of a data matrix constructed from the results for 90 neuropsychiatric patients. None of the models fits the data matrix in an absolute sense, even though all of the models represented an improvement over a null statistical model. For the multifactor models, the best results were obtained by oblique solutions, in which the degree of correlation between the factors varied from .71 to .93. The single-factor model fit nearly as well as, and in some instances better than, many of the multifactor models. The best-fitting model, viz., a three-factor oblique one, was only marginally better in its fit than two of the three two-factor models or the competing three-factor model.

Comparison of two cognitive bedside screening instruments in nursing home residents: a factor analytic study.

The Mini-Mental State Examination (MMSE) and the Blessed Orientation-Memory-Concentration test (BOMC) were each administered to 110 nursing home residents. The correlation between the MMSE and BOMC's total score was -.79. Maximum likelihood factor analysis revealed a two-factor structure, consisting of memory-attention and verbal-comprehension factors that were highly correlated (.69). The results suggest that the somewhat longer MMSE may be preferred for bedside mental status testing, as it clearly measures an additional dimension of cognitive ability, while the BOMC is primarily a unidimensional test. The theoretical and clinical implications of bedside mental status testing of elderly patients are discussed.