2 resultados para Tactile hypersensitivity
em DI-fusion - The institutional repository of Université Libre de Bruxelles
Resumo:
While the number of traditional laptops and computers sold has dipped slightly year over year, manufacturers have developed new hybrid laptops with touch screens to build on the tactile trend. This market is moving quickly to make touch the rule rather than the exception and the sales of these devices have tripled since the launch of Windows 8 in 2012, to reach more than sixty million units sold in 2015. Unlike tablets, that benefit from easy-to-use applications specially designed for tactile interactions, hybrid laptops are intended to be used with regular user-interfaces. Hence, one could ask whether tactile interactions are suited for every task and activity performed with such interfaces. Since hybrid laptops are increasingly used in educational situations, this study focuses on information search tasks which are commonly performed for learning purposes. It is hypothesized that tasks that require complex and/or less common gestures will increase user's cognitive load and impair task performance in terms of efficacy and efficiency. A study was carried out in a usability laboratory with 30 participants for whom prior experience with tactile devices has been controlled. They were asked to perform information search tasks on an online encyclopaedia by using only the touch screen of and hybrid laptop. Tasks were selected with respect to their level of cognitive demand (amount of information that had to be maintained in working memory) and the complexity of gestures needed (left and/or right clicks, zoom, text selection and/or input.), and grouped into 4 sets accordingly. Task performance was measured by the number of tasks succeeded (efficacy) and time spent on each task (efficiency). Perceived cognitive load was assessed thanks to a questionnaire given after each set of tasks. An eye tracking device was used to monitor users' attention allocation and to provide objective cognitive load measures based on pupil dilation and the Index of Cognitive Activity. Each experimental run took approximately one hour. The results of this within-subjects design indicate that tasks involving complex gestures led to a lower efficacy, especially when the tasks were cognitively demanding. Regarding efficacy, there is no significant differences between sets of tasks excepted for tasks with low cognitive demand and complex gestures that required more time to be achieved. Surprisingly, users that declared the biggest experience with tactile devices spent more time than less frequent users. Cognitive load measures indicate that participants reported having devoted more mental effort in the interaction when they had to use complex gestures.
Resumo:
BACKGROUND: Positive skin prick tests (SPT) for food allergens and specific IgE (sIgE) in serum indicate sensitization but do not enable distinction between sensitized but tolerant and clinically allergic patients. OBJECTIVE: Herein, we evaluate the clinical relevance of basophil activation tests (BATs) for peanut or egg allergy diagnosis. METHODS: Thirty-two peanut-allergic, 14 peanut-sensitized (sIgE(+) and/or SPT(+) to peanuts) but tolerant children and 29 controls with no history of an adverse reaction to peanuts were included. Similarly, 31 egg-allergic, 14 egg-sensitized children (sIgE(+) and/or SPT(+) to egg white) and 22 controls were studied. Flow cytometric analysis of CD63 expression or CD203c upregulation on basophils and the production of leukotrienes (LT) were performed in response to an in vitro crude peanut extract or ovalbumin (OVA) challenge. RESULTS: After in vitro peanut challenge, the basophils from peanut-allergic children showed significantly higher levels of activation than those from controls (P<0.001). After OVA challenge, a similar distinction (P<0.001) was observed between egg-allergics and controls. Interestingly, the majority of egg- or peanut-sensitized children failed to activate basophils, respectively, in response to OVA and peanut challenge. The sensitivity of the CD63, CD203c and LT assay was 86.7%, 89.5% and 76.0% with a specificity of 94.1%, 97.1% and 94.6% for peanut allergy diagnosis. The corresponding performances of BATs applied to egg allergy diagnosis were 88.9%, 62.5% and 77.8% for the sensitivity and 100%, 96.4% and 96.4% for the specificity. CONCLUSION: Neither conventional tests nor BATs are sensitive and specific enough to predict food allergy accurately. However, BATs may helpfully complete conventional tests, especially SPT, allowing improved discrimination between allergic and non-allergic individuals.