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David Patterson

Publications and source records attributed to David Patterson.

10 recordsLinked to original sources
PubMed2003

Uncontrolled manifold analysis of single trials during multi-finger force production by persons with and without Down syndrome.

Recently, the framework of the uncontrolled manifold (UCM) hypothesis has been used to study multi-finger synergies based on analysis of motor variability across large sets of trials. We introduce a similar method of analysis, which can be applied to single trials, and hence may be more relevant to studies of atypical populations. In one experiment, results of across-trials and single-trial UCM analysis were compared for control participants who performed accurate ramp force production trials by pressing with four fingers of the hand. Both types of analysis revealed selective stabilization of total force by co-variations of individual finger forces. The stabilization was more pronounced at higher forces. When the participants purposefully varied the relative involvement of fingers during the ramp, significantly higher UCM effects were observed. However, high-pass filtering of the data at 4 Hz made these results similar to those observed in trials with natural patterns of force production. These observations allow assessment of the contribution of processes at two levels of a hypothetical hierarchical control system to the stabilization of total force. We also applied the single-trial UCM method to re-analyze previously published data from another experiment to study the motor variability in a group of persons with Down syndrome (DS) because these persons have difficulty in motor planning and timing as well as in force stabilization. Results of single-trial UCM analysis demonstrated force stabilization in these persons. The degree of force stabilization improved significantly after three days of practice. The analysis also showed that the total pronation/supination moment generated by the four fingers with respect to the midpoint was stabilized. The degree of moment stabilization did not change with practice. We conclude that the single-trial method of UCM analysis allows the analysis of hypotheses about stabilization of different performance variables by alleged multi-finger synergies in both typical individuals and individuals with DS.

Adolescent↗
PubMed2003

Down's syndrome.

The sequencing of chromosome 21 and the use of models of Down's syndrome in mice have allowed us to relate genes and sets of genes to the neuropathogenesis of this syndrome, and to better understand its phenotype. Research in prenatal screening and diagnosis aims to find methods to identify fetuses with Down's syndrome, and reduce or eliminate the need for amniocentesis. Other areas of active research and clinical interest include the association of Down's syndrome with coeliac disease and Alzheimer's disease, and improved median age of death. Medical management of the syndrome requires an organised approach of assessment, monitoring, prevention, and vigilance. Improvements in quality of life of individuals with Down's syndrome have resulted from improvements in medical care, identification and treatment of psychiatric disorders (such as depression, disruptive behaviour disorders, and autism), and early educational interventions with support in typical educational settings. Approaches and outcomes differ throughout the world.

Adolescent↗
PubMed2003

International law, human rights and HIV/AIDS.

This article explores the relevance of international human rights law in the response to the HIV/AIDS epidemic at national and international levels. Public health advocates can use arguments based on this body of law to promote responses to HIV/AIDS that reflect sound public health principles and documented best practice. Development assistance is increasingly linked to rights-based approaches, such as participatory processes, and strategic alliances between health professionals, organizations of people living with HIV/AIDS, and affected communities. Legal and human rights advocacy strategies are increasingly productive and necessary.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Immunomodulators and "on demand" therapy with infliximab in Crohn's disease: clinical experience with 400 infusions.

OBJECTIVES: Infliximab has been proven effective for treatment of active Crohn's and fistulizing Crohn's disease. We reviewed our experience with infliximab in patients with Crohn's disease to determine if its combination with immunomodulators leads to better response and longer periods of disease quiescence. METHODS: We performed a retrospective chart review of 122 patients with Crohn's disease who received infliximab infusions. Data were collected on patient demographics, clinical response to infliximab, fistula response, prednisone dose, infusion reactions/side effects, concomitant immunomodulator therapy, and time intervals between infliximab infusions. RESULTS: Of 122 patients receiving infliximab infusions, 117 completed more than 2 wk of follow-up (400 infusions), and five patients had no follow-up. Co-therapies included azathioprine (AZA) in 47 (40.2%) patients, 6-mercaptopurine (6-MP) in 11 (9.4%), methotrexate (MTX) in 23 (19.7%), prednisone in 64 (54.7%), mesalamine in 51 (43.6%), and antibiotics in 16 (13.7%). Mean follow-up was 52 wk (14-864 days). Overall response rate to infliximab was similar between patients receiving immunomodulators (AZA/6-MP 87.9%, MTX 82.6%) and patients receiving infliximab alone (75%), although there was a trend toward higher response with AZA/6-MP (p = 0.10). More frequent drug reactions/side effects occurred in the infliximab alone group (22.2%) compared with patients receiving MTX (13.0%) and AZA/6-MP (13.8%), but this was not statistically significant. Prednisone dosage was reduced from a mean of 19.5 mg to 7.5 mg per day overall (p < 0.05). Fistula response and dosing intervals were not affected by concomitant immunosuppression. CONCLUSIONS: Concomitant use of immunomodulators with infliximab in patients with Crohn's disease did not improve patient response to several parameters measured, including clinical response rate, dose reduction of prednisone, fistula response, and mean intervals between infliximab infusions.

Adult↗
PubMed2002

Finger coordination in persons with Down syndrome: atypical patterns of coordination and the effects of practice.

The study addresses an issue of possible relations between the apparent "clumsiness" of persons with Down syndrome (DS) and changes in indices of finger coordination. We hypothesized that persons with DS would prefer less challenging, safer motor strategies reflected in finger coordination patterns. Maximal single- and multi-finger force production (MVC) tasks and multi-finger tasks that required the production of a controlled time pattern (ramp) of total force were studied. As compared to typical persons, persons with DS showed lower peak forces, lower force deficit (loss of finger force in multi-finger tasks as compared to single-finger tasks), and higher enslaving (involuntary force production by fingers that are not required to produce force). They showed higher variance of total force computed across several trials for ramp tasks. Their total force variance was higher than the sum of the variances of individual finger forces over the ramp duration, while in control participants the relation was opposite during the middle and late thirds of the ramp. Persons with DS practiced force production tasks over 3 days, one group practicing only one of the tasks (the ramp task with all four fingers acting together) while the other group practiced MVC and ramp tasks (variable practice). Practice led to an increase in MVC, force deficit, and enslaving. The relation between the total force variance and the sum of the variances of individual finger forces became closer to the one observed in typical persons. The effects of practice were more pronounced in the variable practice group. We conclude that persons with DS have a deficit in control of both single fingers and multi-finger groups. They use a less challenging, suboptimal strategy of multi-finger coordination which does not take advantage of the possibility of error compensation among the fingers. Practice is an effective way of improving finger coordination in DS, particularly when using variable tasks.

Adolescent↗
PubMed2002

Indigenous men taking their rightful place in society? A preliminary analysis of a participatory action research process with Yarrabah Men's Health Group.

Men's groups are increasingly being accepted as an important strategy in improving health and well-being, especially in Indigenous communities. However, it is hard to find systematic documentation and evaluation of such initiatives in the literature. This paper analyses the formative stages of a participatory action research (PAR) process which aims to engage and support the members of the Yarrabah Men's Health Group plan, implement and evaluate their activities. Data for the paper are based on a combination of a review of relevant literature, analysis of project documentation, participant observation and discussion and reflection with the participants of the men's group. The paper highlights the importance of (a) using a reflective approach, such as PAR, to engage men's support groups to clearly define the principles and values which both define them and to which they aspire and (b) personal development, education and employment, as a prerequisite for Indigenous men taking greater control and responsibility for their lives. These types of micro-level studies have important implications for the way community development is perceived and approached in Indigenous settings. There are also implications for the roles that academic researchers can play in supporting and adding value to community-driven initiatives to the mutual benefit of both parties.

Community Health Planning↗
PubMedDate not supplied

Corpora analyses of frequency of schwa deletion in conversational American English.

This study utilized two conversational speech databases to generate statistics about the frequency of occurrence of schwa deletion. Overall, the results showed a low frequency of schwa deletion in conversational American English. We investigated a number of factors that could have a potential effect on the propensity to delete schwa. The most pervasive factor was stress environment (pre-stress vs. post-stress), which showed a greater frequency of schwa deletion in the post-stress environment. The results are discussed with reference to processing spoken words and the role for corpus statistics in constraining models of word recognition.

Humans↗