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Biomedical subjects

M Bolduc

Publications and source records attributed to M Bolduc.

10 recordsLinked to original sources
PubMed1998

Risk reconsidered: targets of violence in the social networks of people with serious psychiatric disorders.

Risk Reconsidered: Targets of violence in the Social Networks of People with Serious Mental illness. This exploratory analysis addresses the questions: 1) Who among the members of the social network of a person diagnosed with a major psychiatric disorder is likely to become a target of violence? 2) What kind of relationships do targets have with respondents in terms of the quality and quantity of interactions?, and 3) What are the risk factors that contribute to being a target of violence for people who are in the social networks of persons with serious mental disorders? The samples of 169 people with serious mental disorders were followed for 30 months. A logistic regression model of the risk for being a target of violence among the members of the cohort's social network reveals that both target and respondent characteristics are salient, and that mothers who live with adult children who have schizophrenia and co-occurring substance abuse bear a substantially elevated risk of becoming a target of violence, compared to other social network members. Other factors that elevate the risk for being a target of violence are being an immediate family members of the respondent, more time in residence with the respondent, and whether the respondent is financially dependent on the family. Respondents with the most mental health center visits had lower odds of committing an act or threat of violence against a social network member.

Adult↗
PubMed1993

Discrepancy in the evaluation of visual impairment of elderly low-vision patients by general eye care practitioners and by low-vision practitioners.

Levels of impairment and disability determine eligibility for different welfare programs for visually handicapped persons. General eye care practitioners have to determine the level of impairment for administrative purposes, whereas the low-vision practitioner measures the level of impairment in order to plan the rehabilitation program. We compared the severity of visual impairment reported by the referring practitioners and the one reported by the low-vision specialists for the population of elderly low-vision patients receiving care from one of the largest rehabilitation centers for the visually handicapped in Quebec. Visual acuity ratings reported by general practitioners are lower than those reported by low-vision practitioners. The presence of visual handicap is generally well identified but the severity of visual impairment according to the World Health Organization (WHO)'s categories is not properly gauged by the general eye care practitioners as expressed by the sensitivity and the positive predictive value of the classification of the general practitioners in respect to the classification of the low-vision optometrists. The need to use existing standardized methods to measure visual acuity (VA) is emphasized. It may be hypothesized that this overestimation of the severity of the visual condition may have a negative impact on the process of rehabilitation of the elderly.

Aged↗
PubMed1992

To use or not to use the refractive correction along with hand-held magnifiers.

Equivalent viewing power (EVP), field of view, and working distance (WD) were calculated for 4 different magnifier equivalent powers, four magnifier-to-eye distances, and for uncorrected spherical ametropias varying from +20.00 to -20.00 D in 0.25 D steps. Results show that the various viewing conditions which arise (depending on whether or not the refractive correction is worn) can differ considerably. The uncorrected unaccommodating myope has a greater EVP than the equivalent power of the magnifier if he chooses a magnifier-to-eye distance shorter than the focal length of the magnifier. In this situation, field of view is also enhanced. The uncorrected unaccommodating hyperope using a magnifier-to-eye distance longer than the focal length of the magnifier achieves a stronger EVP than the equivalent power of the magnifier. However, field of view is then reduced. For the uncorrected unaccommodating spherical ametrope, the use of a magnifier-to-eye distance corresponding to the focal length of the magnifier seems to be a good compromise between EVP, field of view, and working distance.

Eyeglasses↗
PubMed1991

Effect of induced blur on visual acuity and stereoacuity.

The acuities of three subjects with good visual acuity and stereoacuity were reduced by the addition of diffusing filters placed before one or both eyes; these subjects then underwent automated stereoacuity and visual acuity tests. Results were idiosyncratic and differed from subject to subject to such an extent that no general rule sufficed to describe the effect of different degrees of blur on visual acuity and stereoacuity. It had been thought that blur degraded stereoacuity more than visual acuity but most of the results from one subject indicated the opposite effect. The effects of monocular vs. binocular blur are discussed.

Form Perception↗
PubMed1989

Routine intraoperative angioscopy in lower extremity revascularization.

The inability to see through blood remains the main obstacle to the widespread and routine use of angioscopy. Local irrigation with a balanced salt solution is presently the most widely used method to clear the blood. By applying basic principles of irrigation and using a unique, dedicated, irrigation pump, we found that routine angioscopy during lower extremity revascularization that yields consistent high-quality studies is feasible, clinically useful, and safe. Between May 1, 1987, and July 31, 1988, 136 intraoperative angioscopies were performed during 112 peripheral bypass procedures, 15 thrombectomies, 2 embolectomies, and 7 miscellaneous revascularization procedures. Mean total irrigation fluid used in the peripheral bypasses was 398 mL (range, 0 to 1400 mL). Good visual quality was obtained in more than 80% of angioscopies and the failure rate was only 1.8%. On the basis of the findings in 71 of the 136 angioscopies, 78 clinical or surgical decisions were made. No complications were directly attributable to the insertion of the angioscope or use of the pump.

Angiography↗
PubMed1988

Relative importance of after-effects, environment and socio-economic factors on the social integration of stroke victims.

This research is about the social integration of victims of a cerebrovascular accident. The objective is to evaluate the relative importance of physical after-effects, socio-economic characteristics, social and environmental factors on the degree of social integration subsequently achieved. This is a longitudinal evaluation with three data collections from an initial sample of 129 persons from the Quebec City area, Canada. Individual functional autonomy increases significantly while in institution and during the six months following discharge. At the time of discharge, 72.9% return to a normal home. A regression analysis shows that the determining factors relating to homecoming are motor functions and autonomy, personal perception of health conditions, proximity of children and relatives, relatively low age, regular presence of another person in the home, and proximity of friends. An important decrease in the practice of many activities occurs six months after homecoming: paid work, housework, management of personal affairs, and leisure activities. Absence of serious motor and language after-effects, a high level of perceived health condition, accessible facilities, proximity of relatives, and the ownership of a car are the factors most strongly associated with continued practice of these activities. Social contacts are more frequent than for comparable populations as far as children and relatives are concerned, but they are less frequent with friends. Proximity is a key factor. A quarter of the sample experiences problems relating to psychological well-being.

Activities of Daily Living↗
PubMed1988

Stereoacuity testing: an illusion of tilt when viewing two parallel vertical rods or lines.

When stereoacuity was measured, some subjects (but not all) saw the two vertical rods of the test to be tilted. The perceived tilt indicated that the top of a rod was nearer to or farther from the observer than the bottom. Sometimes one rod appeared tilted and sometimes both. It was rare for both to appear tilted in the same direction. There are 9 possible tilt combinations including both rods vertical. All were observed but only 1 of the 3 subjects observed them all. In some instances, the frequency with which a particular tilt combination was seen was influenced by which rod was nearer and by the binocular disparity presented by the rods. During a stereoacuity test, tilt can confuse the identification of the nearer rod. Uncertainty is avoided by regarding the middle of the rods. Lines drawn on paper were also seen to tilt by some subjects.

Adult↗
PubMedDate not supplied

Ethanol-induced alterations in EEG alpha activity and apparent source of the auditory P300 evoked response potential.

The relationship among topographic brain electrical activity mapping, auditory-evoked response potentials (ERPs), plasma ethanol levels and subjective reports of intoxication was examined in 4 male volunteers. The source of the auditory P300 ERP (a measure of selective attention and memory encoding) was estimated using a recently developed computer program. The effect of ethanol on the P300 wave was studied using a standard oddball paradigm both with and without a concomitant divided attention task. Ethanol (0.7 g/kg) administration produced marked increases in EEG alpha activity during the ascending limb of the blood ethanol curve. Acute ethanol administration caused a delay in the latency and a reduction in the amplitude of the auditory P300 ERP. A similar effect on P300 topography was noted in waves that were affected by the tones while the subjects also listened to a story (divided attention). After ethanol, the source of the P300 wave appeared to have shifted to a position posterior and inferior to its original location. P300 ERP's generated during the divided attention task were also disrupted and shifted to positions inferior to their original. However, the variability of the dipole vector was much greater during the divided attention task than after ethanol administration. These data demonstrate that ethanol's effects on cognitive processing skills may be similar to those produced when individuals experience distractions while concentrating on a task.

Adult↗