Accuracy of estimates of premorbid intelligence based on demographic variables

Regression equations have been presented for estimating premorbid IQs on Wechsler's intelligence scales, using the demographic variables employed to stratify the various standardization samples as predictors. The accuracy of the resulting estimates for classifying patients into Wechsler's seven IQ categories (from very superior to mentally retarded) was evaluated, and it was found that even the best estimates can be expected to misclassify more than half of all patients. Such estimates still can contribute to valid inferences about a patient's premorbid intelligence, but only when they are used in conjunction with information from other sources.     

Equal weighting vs. differential weighting of subtest scores on short forms of Wechsler's Intelligence Scales

Data from the standardization samples for the WISC-R, the WPPSI, and the WAIS-R were employed to compare the validities and reliabilities of each of several short forms, using (a) the multiple regression weights based on those data, and (b) equal weights. For the short forms of the WISC-R, comparisons were also made using (c) the multiple regression weights reported by the investigators who proposed the short forms, based on their data. The validities and reliabilities varied little from one set of weights to another, so that a strong case can be made for the use of equal weights, which also possess the advantages of simpliciity and robustness.     

The diagnosis of polyarteritis nodosa

We investigated diagnostic testing in polyarteritis nodosa (PAN) by calculating, from published data, the sensitivity and specificity of visceral angiography and muscle, nerve, testicle, kidney, and liver biopsy. Test sequence strategies were constructed by Bayesian inference using a computer program written for this purpose. Test sequences were compared with an aggressive strategy consisting of repeated tests until there was a positive finding or until the available tests were exhausted, and a conservative strategy consisting of 1 biopsy procedure plus angiography. The Bayesian analysis agreed most closely with the conservative approach for most prior probabilities (degree of suspicion) that a patient had PAN. The aggressive strategy had an overall sensitivity of 90% and specificity of 91%, whereas the conservative strategy was 85% sensitive and 96% specific. Furthermore, the aggressive strategy was more costly ($2,986 versus $1,961) and had a higher rate of morbidity (3.8 versus 2.7 days of hospitalization per patient evaluated) than did the conservative strategy. The mortality rates of both strategies were equivalent (∼0.05 deaths per hundred patients evaluated). The per-case cost of diagnosis increased as prevalence decreased, and at 10% prevalence, the aggressive strategy cost more than $17,000 per case diagnosed. Sensitivity analysis revealed that the strategies were moderately affected by the test characteristics, within reasonable assumptions, but that the differences in conservative and aggressive approaches remained. Thus, our analysis based on available data and the assumption of test independence suggests that the preferred diagnostic evaluation of patients with symptoms suggestive of PAN consists, in most cases, of a single biopsy procedure, with angiographic evaluation if necessary.     

Effect of hydrazine sulfate on glucose-regulating enzymes in the normal and cancerous rat

Glucokinase, hexokinase, fructose 1,6-bisphosphatase and phosphoenolpyruvate carboxykinase specific activities were monitored in liver cytosol from rats that had been made cancerous with 1,2-dimethylhydrazine and then treated with hydrazine sulfate. The presence of intestinal cancer, specifically, was confirmed by laparotomy and by histological analysis. Sustained changes in hexokinase and glucokinase specific activities were first evident during the latter weeks that the carcinogen was being administered. Upon subsequent treatment with hydrazine sulfate, glucokinase activity further decreased, and liver cytosolic phosphoenolpyruvate carboxykinase activity increased. Liver cytosolic hexokinase and fructose 1,6-bisphosphatase specific activities were not appreciably affected by the hydrazine sulfate treatment. These results indicate that hydrazine sulfate may influence carbohydrate metabolism at the level of selected liver enzymes not only with respect to gluconeogenesis, but also in terms of glucose uptake.     

Predicting Axillary Nodal Positivity in 2282 Patients with Breast Carcinoma

Axillary lymph node status continues to be the single most important prognostic variable for breast cancer survival despite significant progress in the molecular and genetic characterization of breast malignancies. All patients with invasive breast cancer who underwent axillary lymph node dissection as part of their treatment were evaluated by 11 clinical and pathologic factors, including the primary lesion's T category (TNM staging system), whether the lesion was clinically palpable, the presence of lymphatic or vascular invasion, nuclear grade, estrogen and progesterone receptors, S-phase, age, HER2/neu overexpression, histology (infiltrating lobular or ductal), and ploidy. A total of 2282 axillary dissections were performed: 391 in patients with ductal carcinoma in situ (DCIS) [3 of which (0.8%) contained metastases] and 1891 in patients with invasive breast cancer [680 of which (36%) contained metastases]. Multivariate analysis of patients with invasive cancer identified four factors as independent predictors of axillary lymph node metastases: lymph/vascular invasion, tumor size, nuclear grade, tumor palpability. Among a group of 189 patients with nonpalpable, non-high-grade invasive lesions 15 mm or smaller without lymph/vascular invasion, only 6 (3%) had metastases to lymph nodes. If any three of the favorable factors were present, lymph node positivity was 6% or less. Clinical and pathologic feature of the primary lesions can be used to estimate the risk of axillary lymph node metastases. Such risk assessment can be used for the treatment decision-making process.     

An appraisal of three criteria for evaluating the usefulness of WAIS-R short forms

The findings of research on short forms of the WAIS-R are used to illustrate the following points about three criteria for evaluating the usefulness of a short form: (a) the correlation between a short form and the Full Scale is virtually certain to be highly significant; (b) it makes little difference whether the mean IQ on a short form differs significantly from that on the Full Scale; (c) the percentage of disagreements between a short form and the Full Scale in classifying subjects into IQ categories is virtually certain to be unacceptably high. Consequently, there appears to be little justification for regarding the three criteria as criteria.     

Examining the chapman and chapman theory of schizophrenia through continuous word association with two nosological systems

Examined the Chapman and Chapman (1973) theory of excessive yielding to normal response biases in schizophrenia by using the technique of continuous word association. The word association stimulus list included items with single and multiple meanings (homographs) in order to investigate differential response characteristics between single- and multiple-meaning items and the relative neglect of nondominant meaning responses. Several word association variables were examined, including logical relatedness, reaction time, and response productivity. Further, two discrete samples were studied: A DSM-II-diagnosed sample of schizophrenic and nonschizophrenic Ss (N = 61) and a sample (N = 60) diagnosed according to the more contemporary Research Diagnostic Criteria of Spitzer, Endicott, and Robins (1978) with schizophrenic, manic, and schizoaffective disorder diagnoses. Results were not in accord with predictions derived from the Chapmans' theory using either diagnostic approach.