WAIS-III General Ability Index in neuropsychiatry and forensic psychiatry inpatient samples.

The purpose of this study is to examine the WAIS-III General Ability Index (GAI) in a sample of 33 neuropsychiatry inpatients and 47 forensic psychiatry inpatients. The GAI is comprised of the six subtests that form the Verbal Comprehension and the Perceptual Organization Indexes. The GAI, although highly correlated with the FSIQ, was on average 5.3 points higher in the neuropsychiatry sample and 4.2 points higher in the forensic psychiatry sample. The GAI was significantly higher than the Working Memory and the Processing Speed Indexes in both groups. The GAI, a composite measure of verbal and nonverbal intellect, appears to be an appropriate measure for use in day-to-day clinical practice in neuropsychology. To facilitate clinical use, statistically reliable difference scores between the GAI and the WMI and PSI, for the 95% confidence interval, are presented.     

Detecting malingering on the WAIS-III. Unusual Digit Span performance patterns in the normal population and in clinical groups.

In several studies, suppressed Digit Span performance has been proposed as a potential marker for deliberately poor performance in a neuropsychological evaluation. The purpose of this study was to document Digit Span performance patterns in the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; ) standardization sample and selected clinical groups. Base rate tables were generated for the Digit Span scaled score, longest span forward, longest span backward, and the Vocabulary-Digit Span difference score. Cut-off scores for suspecting negative response bias were proposed, and clinical case examples were used to illustrate these scores.     

A confirmatory factor analysis of the WMS-III in a clinical sample with crossvalidation in the standardization sample.

A maximum likelihood confirmatory factor analysis (CFA) of the Wechsler Memory Scale-III (WMS-III) was performed by applying LISREL 8 to a general clinical sample (n=281). Analyses were designed to determine which of seven hypothesized oblique factor solutions could best explain memory as measured by the WMS-III. Competing latent variable models were identified in previous studies. Results in the clinical sample were crossvalidated by testing all models in the WMS-III standardization samples (combined n=1,250). Findings in both the clinical and standardization samples supported a four-factor model containing auditory memory, visual memory, working memory, and learning factors. Our analysis differed from that presented in the WMS-III manual and by other authors. We tested our models in a clinical sample and included selected word list subtests in order to test the viability of a learning dimension. Consistent with prior research, we were also unable to empirically support the viability of the immediate and delayed memory indices, despite allowing the error terms between the immediate and delayed memory subtests to correlate.     

A confirmatory factor analysis of the WAIS-III in a clinical sample with crossvalidation in the standardization sample.

A maximum likelihood confirmatory factor analysis of the Wechsler Adult Intelligence Scale-III (WAIS-III) was performed by applying LISREL 8 to a clinical sample (n=328). Analyses were designed to determine which of the nine hypothesized oblique factor solutions could best explain intelligence as measured by the WAIS-III in the general clinical sample. Competing latent variable models were identified in previous studies and a priori model modifications were made to test derivations of the nine base models. Results in the clinical sample were crossvalidated by testing all models in the normative sample used in the standardization of the scale. Findings in both the clinical and standardization samples supported a six-factor model including Semantic Memory, Verbal Reasoning, Constructional Praxis, Visual Reasoning, Working Memory, and Processing Speed factors. Our analysis differed from that presented in the WAIS-III manual as we tested more complex models of intelligence in addition to the ones evaluated by the test publishers. As a result, a six-factor model that corresponded to an expanded version of a model based on Horn's Gf-Gc theory was empirically supported as having the best fit to the data. More complex derivations of this model failed to achieve sufficient goodness of fit.     

Concordance between the CVLT and the WMS-III word lists test.

The California Verbal Learning Test (CVLT) and the Word Lists Test (WLT) from the Wechsler Memory Scale-III are widely used tests of verbal learning and memory. To examine concordance between these popular tests, we administered both to a diagnostically diverse group of 25 patients. As expected, measures from the two tests were highly correlated, although level of concordance was not as high as might be expected. When diagnostic outcomes were discordant for free recall measures, the CVLT indicated impairment more often than did the WLT.     

Detecting change: A comparison of three neuropsychological methods, using normal and clinical samples.

Detecting change in individual patients is an important goal of neuropsychological testing. However, limited information is available about test-retest changes, and well-validated prediction methods are lacking. Using a large nonclinical subject group (N = 384), we recently investigated test-retest reliabilities and practice effects on the Wechsler Adult Intelligence Scale and Halstead-Reitan Battery. Data from this group also were used to develop models for predicting follow-up test scores and establish confidence intervals around them. In this article we review those findings, examine their generalizability to new nonclinical and clinical groups, and explore the sensitivity of the prediction models to real change. Despite similarities across samples in reliability coefficients and practice effects, limits to the generalizability of prediction methods were found. Also, when multiple test measures were considered together, one or more "significant" changes were common in all (including stable) subject groups. By employing normative cut-offs that correct for this, sensitivity of the models to neurological recovery and deterioration was modest to good. More complex regression models were not more accurate than the simpler Reliable Change Index with correction for practice effects when confidence intervals for all methods were adjusted for variations in level of baseline test performance.     

Exploratory factor analysis of the WAIS-III in a mixed patient sample.

The Wechsler Adult Intelligence Scale-III (WAIS-III) was administered to 152 patients at a VA Medical Center. Means for age, education, and Full Scale IQ were 51.49 years (SD = 13.00), 12.43 years (SD = 2.00), and 92.61 (SD = 14.06), respectively. Of the 152 patients, 69 had substance abuse disorders, 39 had medical/neurological conditions, 27 had both substance abuse and psychiatric disorders, and 17 had psychiatric conditions. The 13 WAIS-III subtests were subjected to a principal-axis factor analysis with oblimin rotation. Four factors were specified to be retained. The Verbal Comprehension, Perceptual Organization, and Processing Speed factors were identical to those in the standardization sample. However, Arithmetic could not be allocated to any factor within the patient sample. The Working Memory factor consisted only of the Digit Span and Letter-Number Sequencing subtests. © 2000 National Academy of Neuropsychology. Published by Elsevier Science Ltd     

Speed and memory in the WAIS-III Digit Symbol--Coding subtest across the adult lifespan.

The primary role of speed in determining Digit Symbol scores is well established. Among the important questions that remain to be resolved are: (1) whether speed accounts for all of the age-related decline in Digit Symbol scores, and (2) whether memory ability makes any significant contribution to Digit Symbol performance, especially after controlling for speed. We analyzed data from the WAIS-III/WMS-III standardization sample to resolve these issues. As expected, speed (Digit Symbol-Copy) correlated very strongly with Digit Symbol--Coding. Memory (Digit Symbol--Incidental Learning or WMS-III index scores) correlated more moderately with Digit Symbol-Coding. Even after controlling for variance in Coding explained by Copying, a statistically significant proportion of the residual variance was explicable in terms of memory functions. The contribution of memory to Digit Symbol--Coding, while relatively small, is real. In addition, a small portion of the age-associated decline in Coding scores cannot be accounted for by Copying scores.     

Rapid, efficient genotyping of clinical tumor samples by laser-capture microdissection/PCR/SSCP.

Background: Mutation analysis is becoming increasingly important in clinical practice, since sporadic mutations in tumors often correlate with prognosis and/or therapeutic response. However, the labor-intensive nature of the molecular analyses has limited the routine clinical use of tumor genotyping. Laser-capture microdissection (LCM) allows procurement of relatively pure tumor cell populations. We have investigated the possibility that the use of laser-capture microdissection would allow elimination of time-consuming intermediate steps in tumor genotyping. Design. Archival formalin-fixed, paraffin-embedded tissues from seven cases of colorectal adenocarcinoma were laser- and hand-microdissected and subsequently evaluated by PCR/SSCP/sequencing for Ki-ras exon 1 and p53 exons 5, 7, and 8. Results. Mutations in Ki-ras exon 1 and/or p53 exons 5 and 7 were detected in five of the seven samples. In the hand-microdissected samples, confident identification of mutations was possible in several cases only after band excision, DNA elution, reamplification, and verification of mutant enrichment by a second SSCP analysis prior to sequencing. In the laser-microdissected samples, confident mutation identification was possible in all cases with direct sequencing of the original PCR product, reducing the time required for molecular analysis to 3 days. Conclusion. Using laser-capture microdissection, mutant signals are strong enough to sequence directly from original PCR products. With rapid, efficient genotyping by LCM/PCR/SSCP, results can be incorporated directly into the surgical pathology report.     

Interpreting atmospheric pollen counts for use in clinical allergy: allergic symptomology.

BACKGROUND: Allergists generally consider atmospheric pollen counts to be an estimate of the antigenic challenge confronting allergic individuals. The nature of this challenge depends on the particular pollen types found in the atmosphere and also the airborne concentration of these pollen types. Both clinical experience and clinical investigations support these assumptions; however, a coherent system for relating pollen counts and allergic symptomology does not exist. OBJECTIVE: This review article will systematically review the medical and technical literature concerning the clinical significance of atmospheric pollen counts. Data sources: This review article will consider three independent bodies of literature: 1) data contrasting human exposure patterns with rooftop pollen counts; 2) data concerning dose-response relationships between atmospheric pollen counts and allergic symptomology; and 3) data concerning methods for indexing atmospheric pollen counts based on a pollen type's in vivo allergenicity and terminal velocity. RESULTS: Three principal results emerged. First, rooftop pollen counts imperfectly approximate human exposure to atmospheric pollen. Differences in both the concentration and type of pollen encountered by humans can be expected to differ from samples obtained on rooftops. Second, allergic symptomology is positively correlated with atmospheric pollen counts. Investigations involving Betula (birch) pollen offer quantitative dose-response models. Complex, nonlinear relationships that seem to reflect both the priming effect and late-phase reactions exist. Last, atmospheric pollen counts can be indexed based on a contemporary application of Thommen's postulates. This system provides allergists with a means to estimate the clinical significance of various pollen types by combining data concerning in vivo allergenicity and terminal velocity. CONCLUSIONS: These conclusions should allow allergists to judge the clinical significance of atmospheric pollen counts with greater sophistication than was previously possible.     

Polymerase chain reaction for the detection of Neisseria gonorrhoeae in clinical samples.

AIMS: To evaluate the use of a cppB gene derived polymerase chain reaction (PCR) assay for direct detection of Neisseria gonorrhoeae in clinical samples. METHODS: A PCR assay was performed on 33 N gonorrhoeae strains and 12 other Neisseria species and other normal genital flora to evaluate the specificity of the chosen cppB primers. The assay was subsequently evaluated with 52 clinical swab samples collected from China. RESULTS: An amplified product of 390 base pairs (bp) was observed with all the N gonorrhoeae strains, each of these products on digestion with the restriction enzyme MspI produced two bands of 250 bp and 140 bp respectively. This set of primers did not produce any amplified product of the expected length with the other non-gonococcal strains tested. For the 52 clinical swabs, 34 were culture positive and PCR successfully detected all these positives. In addition the PCR was positive for two swabs which were culture negative but positive for N gonorrhoeae antigens when tested with the ELISA method (Gonozyme). CONCLUSIONS: This PCR assay is a promising diagnostic tool for detection of gonococci directly from clinical swab samples. Further evaluation is necessary.     

A cautionary note on deviation scores for the WISC-III and WAIS-III

This article highlights some dangers inherent in interpreting individual examinee strengths and weaknesses in WAIS-III and WISC-III profiles. In both manuals, there are tables providing point estimates for determining if a significant difference exists when comparing one subtest to the average of several subtests. However, these point estimates may lead to interpretation errors. A confidence interval approach that provides a solution to the interpretation problem is described and illustrated. These intervals show that differences between a single subtest score and the average subtest score that just reach statistical significance carry the potential of having no clinical significance.