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Biomedical subjects

D W Harper

Publications and source records attributed to D W Harper.

27 records · Page 2Linked to original sources
PubMed1980

Evidence for the role of attentive fields in masking.

A masking task was employed to determine whether predictions derived from the attentive-field postulate of assimilation theory could be verified. The distance between masking and test lines was varied both towards and away from the center of the attentive field. As predicted, masking was greater when the mask was near the center of attention than when it was located at the periphery of the field. A variation of the mathematical formula developed previously to predict visual illusions was employed to fit the individual and group functions found in this study.

Attention↗
PubMed1979

Signal detection analysis of effect of white noise intensity on sensitivity to visual flicker.

Rating scale estimates of sensitivity to visual flicker were obtained from three subjects under 10 different intensities of auditory stimulation. Results indicated reliable "sawtooth"-like changes in sensitivity as a function of increasing intensity of white noise. No systematic and reliable changes were found in estimates of response bias. Theory and future research are discussed with reference to the possible contribution of cortical arousal.

Auditory Perception↗
PubMed1976

Aftereffects of short-term monocular deprivation on critical flicker frequency of the non-occluded eye.

Ten subjects were monocularly deprived for a period of 6 hr. The CFF of the non-occluded eye was determined just before deprivation, at 3 and 6 hr. of deprivation and at 1, 3, 5, and 18 hr. following restoration of binocular vision. Results indicated a large depression in CFF at 6 hr. of deprivation followed by a gradual return to baseline that was virtually complete 18 hr. afterr binocular vision was restored. The results were discussed in terms of previous research and theory.

Differential Threshold↗
PubMedDate not supplied

Changing bowel hygiene practice successfully: a program to reduce laxative use in a chronic care hospital.

Laxative use was significantly reduced in our long-term care facility when an interdisciplinary program based on a philosophy of prevention and health promotion was implemented. Specifically, increased fluid and fiber intake, timely toileting habits, and regular activity/exercise led to a halving of the number of patients receiving laxatives as required, relative to pre-program levels and relative to a control unit not receiving the program.

Aged↗
PubMedDate not supplied

Patterns of outcome measurement in Parkinson's disease clinical trials.

The study examines the pattern of use and clinimetric properties of clinical endpoints used in randomized trials for Parkinson's disease (PD). Randomized drug trials for PD were identified through a Medline search conducted from January 1966 until August 1998. The endpoints used in these trials were abstracted. Reports examining the clinimetric properties of the disease-specific scales used in these trials were also abstracted. Data regarding the consistency, accuracy, discrimination and feasibility of scales used in at least 10% of trials were determined. One hundred and thirty-seven articles met the inclusion criteria; 70.8% of trials used some clinical scale for PD as an endpoint. The Unified Parkinson's Disease Rating Scale (UPDRS) was the most commonly used scale (32.8%). Factors independently associated with the use of the UPDRS included: the study location in the US, mean age of subjects over 62.7 years and publication after 1994. The UPDRS was more thoroughly studied and superior in most clinimetric domains compared to scales developed earlier. Few studies included generic health status (2.9%) or cognitive measures (16.8%) as secondary endpoints. There have been definite improvements in the area of disease-specific measurement in PD trials since the introduction of the UPDRS. The results of studies that used instruments with poor or unreported clinimetric properties should be critically interpreted.

Aged↗