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Biomedical subjects

C Hardyck

Publications and source records attributed to C Hardyck.

15 recordsLinked to original sources
PubMed1998

Reducing urinary tract infections in catheterized patients.

To compare the effectiveness of two drainage systems in controlling urinary tract infections (UTIs), 65 elderly home care patients with indwelling urinary catheters participated in a retrospective intervention study. The patients first used a Foley drainable bag (DB) system, followed by a nondrainable one (NDB). Both systems used a Foley catheter. Data were obtained from physicians, nurses, caregivers, and patients regarding the number of UTIs and hospitalizations that occurred when using each system. Using the DB, 65 patients had 1,395 UTIs, 27 of which required hospitalization. Using the NDB, 2 patients had 71 UTIs, 2 of which required hospitalization. The cost for the non-hospitalization UTIs with DBs was estimated at $1,153,665 compared to $57,890 with NDBs. The hospital costs with DBs were estimated at $274,170 and $15,540 with NDBs. Because DBs were used longer than NDBs (mean = 44.4 months and 8.8 months, respectively), patients who used each bag for the same period of time were compared. When these patients used NDBs they had significantly fewer UTIs (56, with one hospitalization for 7 days) than when they used DBs (242, with 10 hospitalizations for 37 days). Although the cost of purchasing the non-replaceable NDBs is greater, the use of NDBs drastically reduced levels of infection as well as the overall cost to maintain catheterized patients.

Adult↗
PubMed1986

Cerebral asymmetries and experimental parameters: real differences and imaginary variations?

The basic conditions and stimulus parameters of the paradigm usually used to study visual field-hemisphere differences are reviewed. An argument is presented that a majority of published reports using this paradigm are, in fact, the same basic experiment. The similarity of many parameters over experiments constitutes a set of effects whose influence on our interpretations are not determinable since these parameters are seldom varied. Examples of unsuspected effects on lateralization are drawn from three studies carried out by the author and his colleagues.

Attention↗
PubMed1985

The eyes have it: exposure times and saccadic movements in visual half-field experiments.

Several tachistoscopic visual half-field experiments using exposure times in excess of 150 msec have been reported and arguments have been put forth justifying this procedure. An experiment was done investigating visual field accuracy under conditions where eye movement was allowed, following parafoveal exposure. Two control experiments were done to evaluate the viewing conditions. When eye movement is permitted, accuracy in both visual fields reaches 100%. It is concluded that visual field differences found with exposure times greater than 150 msec are due to the active cooperation of the subjects and not due to the justifications advanced by experimenters using long exposure times.

Adolescent↗
PubMed1985

Orienting attention within visual fields: how efficient is interhemispheric transfer?

Five experiments are reported examining the effect of attentional orienting on lexical decisions within visual half-fields. In Experiment 1, following baseline performance, subjects were instructed to improve performance to the right or left of the fixation point. In Experiment 2, trials were run in blocks with all items to one side of the fixation point. In Experiment 3, completely valid position indicators as to the location of the next item to be shown were presented prior to the stimulus item. In Experiment 4, to examine practice effects, no instructions or cuing were given to subjects. In Experiment 5, subjects were urged to improve performance, but with no instructions as to location. As a summary of our results, it can be stated that (a) consistent visual field differences in lexical decision performance are present, even when subjects were informed, prior to viewing, of the spatial location of the next stimulus item. (b) Lexical decision information initially input to one cerebral hemisphere is primarily processed in that hemisphere. Interhemispheric transfer of this type of language information seems to be done primarily as the end product of a cognitive process.

Attention↗
PubMed1984

Choosing sides: on the variability of language lateralization in normal subjects.

We report test-retest reliabilities and individual asymmetries for a lateralized lexical decision task. Although acceptable reliability was found for word recognition, most subjects did not show statistically significant asymmetries, despite a robust right visual field group advantage. Inter-subject variability was unrelated to sex, handedness, or familial sinistrality. We offer some suggestions as to why these differences are to be expected in the study of normal populations.

Adult↗
PubMed1980

Role of cerebral hemispheric processing in the visual half-field stimulus-response compatibility effect.

Two experiments were conducted to test theories of the stimulus-response (S-R) compatibility effect. Stimuli presented above and below a fixation point in the left and right visual field signaled choice responses in the midsagittal plane. Even though the duration of stimulus presentation in Experiment 1 was sufficiently brief, such that the possibility of eye movements was precluded, a visual half-field S-R compatibility effect was still obtained. That such an effect is found when it can be adequately specified to which hemisphere stimulus information is presented suggests that an explanation in terms of cerebral laterality factors be considered. The second experiment employed arbitrary symbols to represent the spatial property of stimuli used in prior experiments, and a similar pattern of results was obtained. These results are discussed in terms of a functional view of cerebral organization.

Dominance, Cerebral↗
PubMed1980

Lateral asymmetry in perceptual judgments of reading disabled, hyperactive and control children.

Three groups of 11 year old boys, classified as reading-disabled/hyperactive, hyperactive, and normal controls, made same-different judgments to pairs of verbal or visuospatial stimuli presented simultaneously to the right or left side of a fixation point. Two experimental paradigms were used, one emphasizing comparison judgments from memory, the other, new comparison judgments. Reading-disabled boys made more errors of judgment than did controls. All subjects exhibited faster reaction times for different judgments of pairs appearing in the left visual field. Reaction times were longer and errors more numerous for judgments made when two stimuli were presented simultaneously, one to each visual field. Differences in performance for the two halves of the visual field are attributed to memory storage effects for overlearned stimuli. The deficiency in interhemispheric comparisons is attributed to immaturity of the cerebral commissures. The reading-disabled group appears to encompass two subgroups with differing modes of information processing.

Child↗
PubMed1977

Handedness and part-whole relationships: a replication.

Nebes' 1971 experiment reporting a deficit in the performance of left-handed subjects on a measure of part-whole relationships was replicated, controlling for family history of handedness and for experimenter knowledge of subject handedness. No differences were found for any comparisons. Results are examined in relation to similar failures to replicate, indicating that the arc-circle measure does not reliably discriminate any visual-spatial differences associated with handedness.

Cognition↗
PubMed1977

Left-handedness.

Explore the source record for details and available documents.

Cerebral Cortex↗
PubMed1976

Left-handedness and cognitive deficit.

Intellectual and performance measures were taken on 7688 school children tested on three behavioral measures of handedness and one measure of eyedness. Test results were compared against all combinations of handedness and eyedness and against a measure of socio-economic level. No relationships of any kind were found. Comparisons of the present results are made against 33 studies concerned with possible deficits associated with left-handedness. The results of the present study combined with a review of the majority of studies on deficit and handedness strongly suggest that the hypothesis of no difference in intellectual and cognitive performance between right- and left-handed subjects can be accepted as true.

Attention↗