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Biomedical subjects

G W Stuart

Publications and source records attributed to G W Stuart.

6 recordsLinked to original sources
PubMed1992

Positive and negative symptoms in the psychoses: multidimensional scaling of SAPS and SANS items.

Recently, the validity of the simple dichotomy between positive and negative symptoms in psychosis has been questioned. A newly admitted group of 114 DSM-III patients with psychotic disorder were assessed using Andreason's positive and negative symptoms scales. Multidimensional scaling, augmented by cluster analysis, was applied to the full item set of these scales and showed clearly that there are three major, independent groups of symptoms: Hallucinations/Delusions, Positive Thought Disorder and Negative Symptoms. Within the Hallucinations/Delusions and Negative Symptoms groups there was some additional structure which does not conform to the SAPS and SANS sub-scales. In particular there was considerable heterogeneity within the Hallucinations/Delusions group, and delusions of persecution may represent a fourth independent dimension of psychopathology which is under-represented in these scales.

Adult↗
PubMed1992

Colour inputs to random-dot stereopsis.

Recently it has been claimed by Livingstone and Hubel that, of three anatomically and functionally distinct visual channels (the magnocellular, parvocellular interblob, and blob channels), only the magnocellular channel is involved in the processing of stereoscopic depth. Since the magnocellular system shows little overt colour opponency, the reported loss of the ability to resolve random-dot stereograms defined only by colour contrast seems consistent with this view. However, Julesz observed that reversed-contrast stereograms could be fused if correlated colour information was added. In the present study, 'noise' (non-corresponding) pixels were injected into random-dot stereograms in order to increase fusion time. All six subjects tested were able to achieve stereopsis in less than three minutes when there was only correspondence in colour and not in luminance, and three when luminance contrast was completely reversed. This ability depends on information about the direction of colour contrast, not just the presence of chromatic borders. When luminance and chromatic contrast are defined in terms of signal-to-noise ratios at the photoreceptor mosaic, chromatic information plays at least as important a role in stereopsis as does luminance information, suggesting that the magnocellular channel is not uniquely involved.

Color Perception↗
PubMedDate not supplied

Construct validation in adolescents of the brief current form of the Parental Bonding Instrument.

We have reported elsewhere the development of a brief version of the Parental Bonding Instrument (PBI), which we have called the Parental Bonding Instrument-Brief Current form (PBI-BC), for use in survey research in adolescent samples. It was shown in that report that PBI-BC retained the factor structure of the original instrument. The structure remained stable in adolescents' ratings of their mothers and their fathers. Given the evidence of a relationship between the dimensions from the original scale and psychopathology, it was expected that the PBI-BC would be similarly related to measures of psychopathology, namely, that there would be a set of positive correlations between the perceived parental bonding styles of high control and low autonomy-giving and measures of pathology, with a negative relationship between pathology and perceived parental styles of high care and low rejection. In addition, the present study explored the relationships between perceived parental styles and bipolar positive and negative self-concept measures, with the expectations that high control and low autonomy would be associated with more negative self-concept and that high care and low rejection would be associated with more positive self-concept. The results generally confirmed these expectations, suggesting that the brief instrument has adequate construct validity and would be particularly useful as a brief index in studies of adolescents.

Acculturation↗
PubMedDate not supplied

Psychological adaptation of nurses post-disaster.

Disasters have the potential to cause major disruptions in lifeline services and family support systems. As caregivers, nurses are required to make difficult choices during national emergencies and may be at risk for experiencing psychological distress following a disaster. This study describes the responses of a group of nurses following Hurricane Hugo, and makes recommendations to minimize the stress placed on nurses working in a time of disaster.

Adaptation, Psychological↗