Executive functioning in psychogeriatric patients: scalability and construct validity of the Behavioral Dyscontrol Scale (BDS)

OBJECTIVES: Item response theory was used to test the scalability of the Behavioral Dyscontrol Scale (BDS). The BDS assesses the control of voluntary movement, working memory and self-monitoring. Construct validity of the BDS was examined with confirmatory factor analysis. METHODS: The BDS was administered to 693 consecutive, community-dwelling visitors of a psychogeriatric day unit (424 women and 269 men between the ages of 50 and 94). Unidimensionality of the BDS was determined using Mokken's scalogram analysis. The BDS total score was correlated with other measures of executive function (Expanded Mental Control Test, category fluency, and alternating graphical sequences) and with episodic memory tests of orientation and delayed picture recognition in order to test a model of distinct latent constructs of executive functioning and episodic memory. RESULTS: Loevinger's scalability coefficient H was 0.58 for the complete item set of the BDS. Subjects can be ordered on the latent dimension of executive ability. The first eight items of the BDS (deleting the insight rating) satisfy the assumption of non-intersecting item characteristic curves (double monotonicity) which means that they comprise a Guttman-ordered scale (H = 0.60). The BDS and three independent measures of executive control strongly correlated with a latent construct of executive functioning (convergent validity). However, discriminant relations with a nonexecutive construct (recognition memory and orientation) could not be demonstrated. CONCLUSIONS: The BDS satisfies criteria for scalability according to item response theory. Its construct validity as an executive-specific measure is as yet unclear.     

SCHISTOSOMIASIS VACCINATION HISTORICAL DEVELOPMENT, PRESENT STATUS AND FUTURE PROSPECTS*

50 years of research on killed or live vaccine for schistosomiasis without successful produc- tion of a human schistosomiasis vaccine are reviewed.     

The importance of encoding instructions and retrieval cues in the assessment of memory in senile dementia

Sixteen senile dementia patients learned a categorized word list under different encoding and retrieval conditions. Recall increased when explanation of the category structure during encoding was combined with category cueing at retrieval. Explanation of the category structure given at presentation of the list to be remembered did not, by itself, increase recall. Also retrieval cueing with category names did not, by itself, facilitate recall. The recall performance of twelve normal elderly differed quantitatively and qualitatively from the performance of the dementia patients. However, patients suffering from senile dementia can, under certain conditions, benefit from the organization in a categorized list. While working with demented patients one has to be prepared to pay attention to the hidden potentials that do not show up spontaneously.     

Efficiency of sex pre-selection of spermatozoa by albumin separation method evaluated by double-labelled fluorescence in-situ hybridization

To evaluate the separation efficiency of Ericsson's two- and three- layer albumin separation methods, semen samples from 21 healthy males were studied. Seven patients already had two or more sons, another seven had two or more daughters and the other seven had primary infertility due to female factors. The semen samples were divided into three aliquots: one remained unprocessed initially, the other two aliquots went through two- and three-layer albumin separation methods respectively. All samples were then stained with X-Y double staining probes. In each group, four or five samples were processed at room temperature, and two or three at body temperature (37 degrees C). The labelling efficiency of X-Y double staining probe was over 99%. The X:Y sperm ratios were even in the original samples. The ratios of the X and Y spermatozoa were altered slightly but significantly after the two- layer (P < or = 0.05) or the three-layer (P < or = 0.005) separation. The alterations occurred only at room temperature. The X spermatozoa increased and the Y spermatozoa decreased, both to a small degree of difference (1.4-3.5%). Double fluorescence in-situ hybridization analysis therefore showed that albumin separation methods do not enrich Y spermatozoa.      

Recognition memory for words and faces in primary degenerative dementia of the Alzheimer type and normal old age

The suitability of Warrington's Recognition Memory Test (RMT) for discriminating between patients with dementia of the Alzheimer type and nondemented elderly subjects was tested in a study with 44 patients (aged 59 to 94) and 45 normal elderly (aged 69 to 92). The patients showed a significant memory deficit, both in Recognition Memory for Words (RMW) and Recognition Memory for Faces (RMF), even when the scores were corrected for verbal intelligence score (WAIS Vocabulary) or a measure of visuoperceptual ability (Raven's Coloured Progressive Matrices, CPM). Word-face discrepancy scores did not differentiate between dementia and normal old age. At the 95%-specificity level, the sensitivity of RMW and RMF for the detection of memory impairment in dementia was 81% and 100% for subjects below 80, and, less satisfactory, 59% and 76% for subjects of 80 years or older. Correlational analysis showed that the patients' RMW and RMF scores were moderately correlated (r = .40). The significant correlation (r = .45) between CPM and RMF suggests that visuoperceptual deficits are involved in deficient face recognition.     

Relationship between image quality and ultrasound exposure level in diagnostic US devices

Ultrasonographic B-mode images were obtained at various exposure levels with three real-time diagnostic scanners. Adult human and tissue-equivalent phantom images were compared in terms of diagnostic content and depth of penetration. For the exposure level settings used, spatial-peak pulse-average intensities ranged from approximately 10 to 500 W/cm2. At the 3.50-3.75-MHz nominal frequencies used in the study, images of the human abdomen showed little discernible change in quality with varying exposure levels. However, phantom tests confirmed that depth of penetration is a function of exposure level. The results suggest that a judicious use of exposure level and receiver gain controls can be a practical means for minimizing patient exposure to ultrasound without sacrifice of diagnostic effectiveness.