Louise Sauvé | PubMed Health

PubMed2005

Scene perception, gaze behavior, and perceptual learning in virtual environments.

More and more immersive environments are developed to provide support for learning or training purposes. Ecological validity of such environments is usually based on learning performance comparisons between virtual environments and their genuine counterparts. Little is known about learning processes occurring in immersive environments. A new technique is proposed for testing perceptual learning during virtual immersion. This methodology relies upon eye-tracking technologies to analyze gaze behavior recorded in relation to virtual objects' features and tasks' requirements. It is proposed that perceptual learning mechanisms engaged could be detected through eye movements. In this study, nine subjects performed perceptual learning tasks in virtual immersion. Results obtained indicated that perceptual learning influences gaze behavior dynamics. More precisely, analysis revealed that fixation number and variability in fixation duration varied with perceptual learning level. Such findings could contribute in shedding light on learning mechanisms as well as providing additional support for validating virtual learning environments.

Adult↗

PubMed2003

Prevalence of metabolic alterations predictive of cardiovascular disease risk in the Québec population.

BACKGROUND: It is well established that cardiovascular diseases (CVD) are the most important cause of morbidity and mortality in North America and in industrialized countries. Furthermore, the presence of CVD risk factors is widespread in Canada, and two-thirds of adult Canadians present at least one traditional risk factor for CVD. OBJECTIVE: To quantify the prevalence of metabolic alterations predictive of an increased risk of CVD in a representative sample of the Québec population. METHODS: A representative sample of the Québec population was obtained through the Québec Health Survey 1990. The cohort of 1844 subjects (907 men and 937 women), aged from 18 to 74 years, completed the evaluation, which consisted of interviews, validated questionnaires for personal and family history of CVD risk factors, and a physical examination. Anthropometric measurements, blood pressure, fasting plasma lipoprotein-lipid levels as well as fasting glucose and insulin concentrations were obtained. RESULTS: Thirty one per cent of the Québec population had a normal body weight defined by body mass index (BMI) less than 25 kg/m2 with a healthy metabolic profile (glycemia less than 6.1 mmol/L, total cholesterol less than 5.2 mmol/L, low density lipoprotein-cholesterol less than 3.4 mmol/L, triglycerides less than 2.3 mmol/L and high density lipoprotein-cholesterol greater than 0.90 mmol/L). On the other hand, 28% of the population was treated for known metabolic chronic diseases (CVD, diabetes, dyslipidemias and hypertension), whereas the remaining 33% of the Québec population (BMI greater than 25 kg/m2) were characterized by an altered metabolic profile predictive of an increased CVD risk. Furthermore, 75% of men and 70% of women with an altered metabolic profile presented at least two CVD risk factors. Overall, women tended to display a significantly healthier metabolic risk profile than men (P<0.05). CONCLUSIONS: According to our results, only 31% of the Québec population is nonobese without major alterations in their metabolic risk profile. Indeed, 61% of Quebecers are either characterized by chronic diseases or by an altered metabolic profile increasing their risk for the development of CVD and type 2 diabetes. Such a high prevalence should be a source of concern justifying the development of simple screening tools for early identification of the asymptomatic carriers of this cluster of metabolic abnormalities.

Adolescent↗