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Visual Reaction Time (visual + reaction_time)

Distribution by Scientific Domains
Medical Sciences80%

Selected Abstracts

Evaluation of a new method of assessing depth of sedation using two-choice visual reaction time testing on a mobile phone,

ANAESTHESIA, Issue 1 2009
A. J. Thomson
Summary The utility of two-choice visual reaction time testing using a specially programmed mobile telephone as a measure of sedation level was investigated in 20 healthy patients sedated with target controlled infusions of propofol. At gradually increasing target concentrations visual reaction time was compared with patient-assessed visual analogue scale sedation scores and an observer-rated scale. Propofol sedation caused dose-dependent increases in visual reaction time and visual analogue scale scores that were statistically significant when the calculated effect-site concentration reached 0.9 ,g.ml,1 (p < 0.05) and 0.5 ,g.ml,1 (p < 0.01) respectively. While visual analogue scale scores were more sensitive at lower levels of sedation than visual reaction time, the latter demonstrated marked increase in values at higher levels of sedation. Visual reaction time may be useful for identifying impending over-sedation. [source]

An electromyographic investigation of the effect of stimulus,response mapping on choice reaction time

PSYCHOPHYSIOLOGY, Issue 1 2001
Thierry Hasbroucq
The activity of the agonist muscles was recorded during the performance of a two-choice visual reaction time (RT) task in which the compatibility of the stimulus,response mapping was manipulated. Correct trials were distinguished according to whether or not the activation of the agonist of the required response was preceded by an activation of the agonist of the nonrequired response. Double activation trials were more numerous for the incompatible than for the compatible mapping. Furthermore, these trials yielded longer RTs than the single muscular activation trials. These results suggest that initial activations of nonrequired responses are more frequently aborted and corrected when the mapping is incompatible than when it is compatible. This finding supports the dimensional overlap model of stimulus,response compatibility (S. Kornblum, T. Hasbroucq, & A. Osman, 1990). [source]

Evaluation of a new method of assessing depth of sedation using two-choice visual reaction time testing on a mobile phone,

ANAESTHESIA, Issue 1 2009
A. J. Thomson
Summary The utility of two-choice visual reaction time testing using a specially programmed mobile telephone as a measure of sedation level was investigated in 20 healthy patients sedated with target controlled infusions of propofol. At gradually increasing target concentrations visual reaction time was compared with patient-assessed visual analogue scale sedation scores and an observer-rated scale. Propofol sedation caused dose-dependent increases in visual reaction time and visual analogue scale scores that were statistically significant when the calculated effect-site concentration reached 0.9 ,g.ml,1 (p < 0.05) and 0.5 ,g.ml,1 (p < 0.01) respectively. While visual analogue scale scores were more sensitive at lower levels of sedation than visual reaction time, the latter demonstrated marked increase in values at higher levels of sedation. Visual reaction time may be useful for identifying impending over-sedation. [source]

Effects of Alzheimer's disease and mild cognitive impairment on driving ability: a controlled clinical study by simulated driving test

INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 3 2009
Cristina Frittelli
Abstract Objective To assess the effects of Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI) on simulated car driving ability. Methods Twenty patients with a probable AD of mild severity (Clinical Dementia Rating, CDR,=,1) were compared with 20 subjects with MCI (CD,=,0.5), and a group of age-matched neurologically normal controls on a driving simulation task. Measures of driving competence included the length of run, the number of infractions (omission of stop at pedestrian crossings, speed limits violation), the number of stops at traffic lights, the mean time to collision, and the number of off-road events. Results in the driving competence measures were correlated with scores obtained from simple visual reaction times and mini-mental state examination (MMSE). Results The patients with mild AD performed significantly worse than MCI subjects and controls on three simulated driving measures, length of run and mean time to collision (p,<,0.001), and number of off-road events (p,<,0.01). MCI subjects had only a significantly shorter time-to-collision than healthy controls (p,<,0.001). Simple visual reaction times were significantly longer (p,<,0.001) in patients with AD, compared to MCI and healthy controls, and showed a borderline significant relation (p,=,0.05) with simulated driving scores. Driving performance in the three groups did not significantly correlate with MMSE score as measure of overall cognitive function. Conclusions Mild AD significantly impaired simulated driving fitness, while MCI limitedly affected driving performance. Unsafe driving behaviour in AD patients was not predicted by MMSE scores. Copyright © 2008 John Wiley & Sons, Ltd. [source]