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T Bryant

Publications and source records attributed to T Bryant.

11 recordsLinked to original sources
PubMed2000

6-(18)F-DOPA PET study in patients with schizophrenia. Positron emission tomography.

Presynaptic dopamine metabolism was studied in a group of patients with schizophrenia and in an age- and gender-matched normal control group using 6-[(18)F]fluoro-L-DOPA ((18)F-DOPA) and positron emission tomography (PET). Nineteen patients, nine drug-free, 10 on neuroleptics, and 13 normal control subjects underwent PET scans using (18)F-DOPA. The neuroleptic-treated patients were taking typical neuroleptics (N=4) or the atypical neuroleptic, clozapine (N=6). The ratio of specific/non-specific activity was calculated for eight cortical and subcortical regions of interest. Medication-free patients had a significant reduction in (18)F-DOPA uptake in the ventral striatum (P=0.04) and significantly increased uptake in the posterior cingulate (P=0.02) compared with normal control subjects. The 18F-DOPA PET technique proved to be useful and sensitive in detecting changes in dopamine metabolism in patients with schizophrenia in vivo. The results of this study provide evidence of an aberrant dopamine system in schizophrenia.

Adult↗
PubMed1997

Axial lower-limb alignment: comparison of knee geometry in normal volunteers and osteoarthritis patients.

Osteoarthritis of the knee is associated with deformities of the lower limb and malalignment of the limb segments. Pathogenetic relationships between the two are poorly understood. Alignment was studied by standardized radiography in 167 symptomatic Canadian osteoarthritis patients, and compared with 119 healthy adult volunteers. In healthy adults overall alignment (hip-knee-ankle angle) was principally determined by distal femoral valgus (condylar hip angle) and proximal tibial-plateau varus (plateau-ankle angle): the angle between the joint surfaces (condylar plateau) was relatively constant. In osteoarthritis, disease-associated differences included condylar-plateau angles that were divergent: accentuated medial convergence in varus osteoarthritis and lateral convergence in valgus osteoarthritis. This was interpreted as change arising from focal loss of cartilage in the medial (varus osteoarthritis) or lateral (valgus osteoarthritis) compartments of the knee. The changes would contribute to increasing limb malalignment during disease progression. But differences of limb geometry also contributed to malalignment. These were the average trends: in varus osteoarthritis there was abnormal femoral geometry (lesser femoral condylar valgus), but tibial surface geometry was the same. In valgus osteoarthritis, the opposite was true: abnormal tibial geometry (lesser plateau varus), but normal femoral geometry. A possible explanation is that these abnormal knee geometries pre-exist and predispose to osteoarthritis, although it is not impossible that they (like condylar-plateau angle) change as disease progresses. Further approaches to population studies are discussed based on these findings, along with their implications for knee surgery.

Adult↗
PubMed1995

Development of factor-score-based models to explain and predict maximal box-lifting performance.

The objectives of the study were threefold: (1) to develop factor-score-based models to predict maximum mass on a box-lifting task using multiple regressions; (2) to compare predictive and explanatory powers of factor-score-based models to models derived from data-level variables; and (3) to apply these findings to ergonomic research and practical problem-solving situations. Forty-eight volunteers (25 women and 23 men) completed a maximal box-lifting task and a maximal isoinertial lifting test on an Incremental Lifting Machine (ILM). Dynamic data collected during isoinertial testing were summarized into 32 lift parameters, and then subjected to principal components analyses using the 'FACTOR PROCEDURE' from the Statistical Analysis System (SAS). Factor scores were calculated for each participant on each of the four factors comprising the final solution, and multiple regression equations for men, women and combined data were generated using the 'GENERAL LINEAR MODELS' procedure from SAS. Results revealed that prediction of box-lifting performance was optimized when regression equations were developed using numerous data-level variables as predictors, i.e., all 32 lift parameters and ILM mass. In comparison, explanation was enhanced but predictive capabilities were reduced when linear models were formed using ILM mass and the factor scores derived from analyses of isoinertial lifting. The use of variables loading on the factors gave slightly increased predictive power than did the factor-score-based models. Similar trends in predictive and explanatory powers appeared when the data were analysed according to gender. Ergonomic applications of factor-score-based models were discussed with regard to ongoing research as well as to practical problem-solving situations. It was concluded that the advantages and usefulness of factor-score-based models warranted their inclusion in future investigations of lifting performance.

Adult↗
PubMed1993

Adapting the Rivermead Behavioural Memory Test for use with children aged 5 to 10 years.

We describe modifications made to the Rivermead Behavioural Memory Test (RBMT) to make it appropriate for use with children. Results of a sample of 335 children aged 5 to 10 years, attending mainstream schools, are reported. Each child was given two of the four versions of the modified test for children together with a number of tests of memory and achievement from the Wechsler Intelligence Test for Children (Revised WISC-R), and the British Ability Scales (BAS). The children's version of the behavioural memory test (RBMTC) has good interrater and parallel from reliability. The validity of the RBMTC was established in two ways. First, with other tests of memory from the WISC and BAS. Second, a small (n = 36) group of children with severe epilepsy and memory difficulties, attending a residential school, were tested. The houseparents of these children were asked to complete rating scales on everyday memory performance. There was significant agreement between houseparents' observations and scores on the RBMTC (Spearman rank correlation = .71, p < .001), indicating that the test is indeed assessing everyday memory.

Child↗
PubMed1990

The effect of lifting protocol on comparisons with isoinertial lifting performance.

The purpose of the study was threefold: (1) to determine if protocol constraints affected scores on a box-lifting task; (2) to identify any differences in impact of protocol changes on male and female scores; and (3) to determine if these protocol changes affected correlations between maximal box-lifting scores and maximal scores obtained on isoinertial lifting tests. Two hundred and sixty nine participants (143 males and 126 females) completed maximal isoinertial lifting tests to 1.50 m and 1.80 m using a constrained protocol on an Incremental Lifting Machine (ILM). Participants were divided into three samples for completion of a maximal box-lifting task, with each sample using one of the following task protocols: (1) set style; (2) free style; and (3) ergonomically redesigned. Statistical analyses using general linear models procedures revealed that changes in protocol constraints significantly affected scores on lifting tasks. Removal of protocol constraints resulted in greater percentage increases in task scores for females than for males. Furthermore, disparate patterns between genders in task-test correlations were observed. It was concluded that the ILM was unable to predict female lifting capabilities accurately using any of the three protocols.

Anthropometry↗
PubMedDate not supplied

Predicting severity of cognitive impairment after severe head injury.

It is often assumed that age is an important variable in determining cognitive outcome following severe head injury. The present study was carried out to determine whether age at time of injury predicted severity of cognitive impairment. Our hypothesis was that the older the patient at time of head injury the worse should be the cognitive impairment. Cognitive impairment was assessed by scores on nine standardized tests. Scores were obtained from 144 consecutive referrals to a clinical psychologist; all subjects had sustained a severe head injury. Of these, 115 had suffered a closed head injury. Ages ranged from 13 to 65 years. Apart from Unusual Views and Verbal Fluency no significant correlations were found between age and test performance. Thus there was little evidence that age predicted performance on cognitive tests. A number of significant correlations were found between length of coma and cognitive performance. The findings would seem to confirm that cognitive outcome after severe head injury is predicted by length of coma (which reflects severity of brain damage) whilst age at time of injury does not appear to be a good predictor of outcome.

Activities of Daily Living↗
PubMedDate not supplied

How government policy decisions affect seniors' quality of life: findings from a participatory policy study carried out in Toronto, Canada.

Toronto seniors explored how government policy decisions were influencing their health and well-being. In this participatory policy study, emphasis was upon the lay and critical knowledge of highly informed seniors. Focus groups and interviews revealed that all three levels of governments were seen as not listening to seniors' voices. In nine key policy areas identified as influencing seniors' quality of life--hearing seniors' voices, housing, acute illness care, long-term care, income supports, transportation and mobility, promoting healthy lifestyles, access to information, and hearing voices from cultural communities--many concerns were raised. The gap between government rhetoric and government action on seniors' issues merits public health attention.

Aged↗