Biomedical subjects

P J Bryden

Publications and source records attributed to P J Bryden.

12 recordsLinked to original sources

PubMed2005

Unimanual performance across the age span.

The purpose of the current investigation was to examine the age-related changes in the performance of the two hands on the Annett pegboard (Annett, 1970). The current study was part of a large-scale study investigating the development of unimanual and bimanual performance. Three hundred and two right-handed individuals participated in the present study, comprising five different age groups (3-5 year olds, 6 and 7 year olds, 8 and 9 year olds, 10-12 year olds, and 19-24 year olds). All participants completed the Waterloo Handedness Questionnaire and the standard Annett pegboard. Analyses revealed significant overall performance differences between the hands, as expected, where the right hand was significantly faster than the left hand. Additionally, significant performance differences between the hands were noted as a function of age. More specifically, the adults showed a much smaller performance difference between the hands than the other age groups. The results are discussed in light of current theories of the development of hand preference and manual asymmetry.

Adult↗

PubMed2005

A new method of administering the Grooved Pegboard Test: performance as a function of handedness and sex.

The purpose of the present study was twofold: first to examine the influences of sex and handedness on manual performance on the Grooved Pegboard Test; and secondly to provide normative data for two versions (Place and Remove tasks) of the Grooved Pegboard Test, as previous work (Bryden & Roy, 1999) had suggested that the Remove task of the Grooved pegboard may provide a purer measure of motor speed of the two hands than the standard administration of the Grooved Pegboard Test. One hundred and fifty-three (47 males and 106 females) participants completed the Grooved Pegboard Test. Individuals performed the standard version of the Grooved Pegboard Test (Place task) and a novel version of the test (Remove task). In the standard version, participants were timed on their speed for placing the pegs, while in the novel version they were timed on their speed for removing the pegs. Results confirmed previously noted hand and sex differences in the Place task of the Grooved Pegboard Test, as well as the lack of effect of handedness on performance (Bornstein, 1995; Ruff & Parker, 1993). Significant performance differences between the hands were also noted for the Remove task. Findings also indicated that the Remove task was sensitive to sex and handedness effects.

Adolescent↗

PubMed2005

Handedness and health: an examination of the association between different handedness classifications and health disorders.

The current study investigated the incidence of various health disorders in a sample population of undergraduate students, using a 25-item hand preference questionnaire. Analysis revealed significant differences existed in the incidence of several health disorders as a function of handedness: however, these differences depended on how hand preference was defined. Overall, the results showed that non-right-handed participants (i.e., those individuals with left-handed, ambidextrous, or inconsistent hand preferences) were significantly more likely to report specific health disorders (such as high blood pressure and epilepsy) than right-handed participants. The findings provide support for the argument that left-handedness, or non-right-handedness, is associated with various health disorders. The results are discussed in light of the Geschwind-Behan-Galaburda model of cerebral lateralisation.

Adolescent↗

PubMed2001

Knowledge of the risks and benefits associated with oral contraception in a university-aged sample of users and non-users.

As research has shown that knowledge concerning the health risks and benefits of oral contraceptive (OC) use is a contributor to OC compliance, the following study examined an educated sample of young women to determine the level of knowledge concerning the risks and benefits of OC use. A 28-item questionnaire was developed by the research team and distributed to female undergraduate students. Five questions were designed to assess the respondent's knowledge of OC. Overall, it found that OC users answered 71.9% of the questions correctly, whereas non-users answered significantly fewer questions correctly. As well, the number of correct responses increased with academic year, indicating that younger women were less knowledgeable about OC. The results of this study indicate that despite increased efforts to educate women, knowledge of OC remains a major problem, even in a sample of women with relatively high socio-economic status.

Adolescent↗

PubMed2001

Preliminary examination of oral contraceptive use among university-aged females.

The etymology and use of oral contraceptives (OCs) has greatly influenced the sexual practices and social lives (e.g., decisions concerning childbearing, careers) of adolescent and adult women. In addition, OCs have the potential to benefit or harm its users depending upon the utilization practices and characteristics/lifestyle habits of the women consuming them. A 28-item questionnaire was distributed to female students at a university in Central Ontario and examined: (1) socio-demographic information; (2) background information concerning oral contraceptive use (e.g., length of time taking the pill, concerns about pill use, side effects while on the pill); and (3) procedure for taking the pill (e.g. maximizing effectiveness and safety). Preliminary analysis indicated that females may not be equipped with adequate knowledge or receiving the necessary support to practice the most efficacious behaviours surrounding pill use.

Adolescent↗

PubMed2001

Can I twist your arm? The influence of target orientation on the magnitude of the right-hand advantage.

Controversy exists concerning whether handedness is a unidimensional trait or a multidimensional trait. However, researchers espousing the view that handedness is multidimensional are in disagreement regarding what the dimensions are that underlie handedness. Healey, Liederman, and Geschwind (1986) have provided some evidence that the type of musculature utilised (i.e., proximal versus distal) may be an underlying factor in determining handedness. The present research attempted to test this notion by examining the effects of target orientation on the relative performance of the two hands, using a peg-moving task. Target orientation was examined by utilising key-shaped pegs that fit securely into key-shaped holes. The results showed that the presence of target orientation increased the preferred-hand advantage. It is considered that this increased advantage for the right hand may be due to the hemispheric control of proximal versus distal musculature suggested by Geschwind and Galaburda (1985).

Journal Article↗

PubMed2000

A performance measure of the degree of hand preference.

The present paper describes a performance method for determining hand preference. The task requires participants to reach into different regions of hemispace to perform various actions (point, pick up, toss, sweep, and position) with a dowel located at each position. In accordance with the participants' hand preference as measured by the Waterloo Handedness Questionnaire, the preferred hand was used more frequently on the various performance tasks. The distribution of hand use in working space indicates that preferred hand use was almost exclusive for actions carried out in ipsilateral hemispace, while it is used only moderately for actions in contralateral hemispace, revealing that this hand is used throughout a wider range of extrapersonal space than the nonpreferred hand. These trends were observed across all of the performance tasks, suggesting that task complexity did not affect the frequency of preferred hand use either overall or, more specifically, in right hemispace, as was predicted. This finding is inconsistent with empirical work on questionnaires indicating that verbal reports of preferred hand use increase for more complex tasks (e.g., Steenhuis & Bryden, 1988). As well, performance on the preferential reaching task correlated significantly with hand preference as measured on the Waterloo Handedness Questionnaire (Bryden, 1977), unlike the other performance measure examined, indicating that the preferential reaching task is sensitive to differences in the degree of hand preference.

Adult↗

PubMed1999

Spatial task demands affect the extent of manual asymmetries.

The degree of hand preference and the magnitude of hand differences in performance are thought to relate to skill level. The purpose of the experiments discussed here was to examine the effect of skill as reflected in the spatial precision demands of a movement, on the extent of manual asymmetries. Experiment 1 utilised the Annett pegboard, and manipulated spatial precision by varying peg diameter. The second experiment utilised the Grooved pegboard, and manipulated spatial precision by altering the size of the target hole. Analyses revealed that movement time increased as a function of the increased spatial precision demands. Although the preferred hand was always faster, the magnitude of this advantage was only affected in Experiment 2, in which the manipulation of spatial precision was maximal. The implications of these findings for the skill interpretation of handedness are discussed.

Journal Article↗

PubMed1994

An examination of colour-contingent pattern aftereffects.

The McCollough effect (ME) is an example of a pattern-contingent colour aftereffect. This study describes some characteristics of another visual aftereffect linking pattern and colour here called a colour-contingent pattern aftereffect (CCPA). After inducing with, for example, a magenta and black radial pattern and a green and black pattern of concentric circles, presentation of a green homogeneous field evoked a faint image of a radial pattern superimposed on the field, whereas presentation of a magenta homogeneous field produced a faint image of concentric circles. The pattern was blurred and fleeting, occurring with the onset of the homogeneous field, but nevertheless was evoked reliably. Various properties of these colour-contingent pattern aftereffects are reported. Although the aftereffects have some of the characteristics of the ME, the CCPA is not as long lasting as the ME, and, unlike the usual ME, it is abolished if eye-movements are made during induction.

Color Perception↗

PubMedDate not supplied

A developmental analysis of the relationship between hand preference and performance: II. A performance-based method of measuring hand preference in children.

The present study describes a performance-based method of measuring hand preference in children. Three aspects of handedness were considered to be important in developing the paradigm (a) overall hand preference across a number of tasks, (b) consistency of hand use and, (c) the use of the preferred hand in a bimanual task. The new paradigm, termed the WatHand Box Test (WBT), requires participants to perform a variety of unimanual tasks such as, using a hammer, tossing a ball, and opening a lock with a key. To determine the validity of the WBT and examine the developmental trends in hand preference, eighty right-handed children and adults (ages 3-4, 6-7, 9-10, and 18-24 years) performed the WBT. First, the WBT was found to correlate significantly with scores on a standard hand preference questionnaire for the adults. As well, significant developmental trends were noted in hand preference as measured by the WBT. Most specifically, three- and four-year-olds had significantly lower scores on the WBT indicating a less stable pattern of hand preference than in the other three age groups.

Adolescent↗

PubMedDate not supplied

A developmental analysis of the relationship between hand preference and performance: I. Preferential reaching into hemispace.

The present study describes a developmental performance measure of hand preference that considers task complexity and position in hemispace. Eighty right-handed children and adults (ages 3-4, 6-7, 9-10, 18-24) were observed for hand selection responses to 2 unimanual tasks (simple vs complex) across positions in hemispace. Results revealed an age-related trend in the tendency to use the preferred hand in right and left hemispace. While the adult's and 3- to 4-year-old's preferred hand use decreased as they moved into left hemispace, children between the ages of 6 and 10 years tended to use their preferred hands consistently throughout both regions of hemispace. The relationship between hand preference and skilled, cost-efficient performance throughout development are discussed.

Adolescent↗

PubMedDate not supplied

Posture and target location effects on manual preference.

Twenty-nine right-handed participants made unimanual movements to 5 target locations while standing and while balancing on a rocker platform. Manual preference was affected by target location (p < .001; manual preference tended to be concordant with target hemispace) and posture (p < .05; responses from the rocker platform were associated with a lower level of right-hand responding). A location by posture interaction (p < .05) indicated that the effect of posture was present only for targets in left hemispace; the right hand was used less frequently in the rocker condition than simple standing. Manual preference is viewed as a process of response selection motivated by an effort to minimize neural processing and mechanical costs.

Brain↗