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Functional Neurology
Published in James Crossley, Functional Exercise and Rehabilitation, 2021
Imagine driving down a road and a child suddenly runs out in front of the car. We have fractions of a second to save that child’s life. To generate an appropriate response, the brain receives sensory feedback (i.e. the girl running in front of us), interprets that feedback (i.e. the level of danger based on where they are and the speed we are going), selects an appropriate response (i.e. break or swerve out of the way) and sends a motor signal to activate muscles (i.e. to turn the wheel). The time it takes for all this to happen is known as reaction time. Scientists measure reaction times using various methods: Reaction sticks that are dropped and have to be caught as fast as possible. The test can be replicated using a ruler.Light board reaction tests assess the time taken to touch lights appearing in a random order on a light board in front of the person. This test has been used as one of a panel of tests by American Football League Teams to test players before they enter the draft.The average human reaction time is typically 0.25 seconds to a visual stimulus, 0.17 for an audio stimulus and 0.15 seconds for a touch stimulus. Reaction times are ‘hard-wired’ and depend on the time it takes for sensory signals to pass from the periphery to the brain and from the brain to the muscles. Reaction times are not changeable or trainable.
Investigative Duties on Scene
Published in Kevin L. Erskine, Erica J. Armstrong, Water-Related Death Investigation, 2021
Alcohol intensifies the effects of wind, heat, boat motion, and fatigue, which adversely affects balance, judgment, and reaction time. These stressors weaken the body, making the chance of an accident much greater. Sitting in the sun increases your body heat, and this in turn causes sweating. As a person rides in a boat, his or her body constantly adjusts to the position of the boat. This constant adjustment increases body heat and fatigue. Sweating and alcohol consumption cause severe dehydration. Dehydration causes fatigue, irritability, headaches, and sleepiness. All these factors increase the risk of an accident. Research has proven that one-third of the amount of alcohol it takes to make a person legally intoxicated on land can make a boater equally impaired on the water. Alcohol use impairs judgment and slows reaction time. Most people can become impaired with only one drink. It makes it difficult for the operator to pay attention and perform simple tasks, such as keeping track of other vessels operating in the immediate area. In emergency situations, this can be critical if the operator is forced to make an immediate decision. For these reasons, alcohol consumption while boating significantly increases the likelihood of accidents. Table 2.5 shows areas of impairment due to varying blood alcohol concentration (BAC) while boating.
Preimplantation Genetic Testing for Aneuploidies: Where We Are and Where We're Going
Published in Darren K. Griffin, Gary L. Harton, Preimplantation Genetic Testing, 2020
Andrea Victor, Cagri Ogur, Alan Thornhill, Darren K. Griffin
MDA is a non-PCR-based method for WGA. MDA uses high-fidelity bacteriophage DNA polymerase that denatures double-stranded DNA and amplifies a single-stranded template in an isothermal reaction. The high-fidelity polymerase reduces nucleotide errors in amplified sequences, which is well suited for single nucleotide polymorphism (SNP) detection; however, its amplification uniformity across the genome appears hampered compared to PCR-based methods [57]. Though minimal hands-on time is required, the reaction time can be greater than 8 hours.
Midfrontal Theta and Cognitive Control During Interlimb Coordination Across the Adult Lifespan
Published in Journal of Motor Behavior, 2023
Siel Depestele, Kim van Dun, Stefanie Verstraelen, Sybren Van Hoornweder, Raf Meesen
In line with previous literature, an age-complexity effect was present, evidenced by the larger increase in reaction time during complex movements in older relative to younger adults (Boisgontier et al., 2016; Rasooli et al., 2021; Van Hoornweder et al., 2022). Importantly, this age-complexity effect was already present in middle-aged adults, as reaction time increased significantly from simple to complex movements, and there was no longer a significant difference in reaction time between the middle-aged and older adults for the more complex movements. This finding corroborates previous research, which also found that reaction time in interlimb coordination, and in a button-pressing paradigm is already compromised at middle-age (McEvoy et al., 2001; Rasooli et al., 2021). Yet, Berchicci et al. (2012) found that reaction time was maintained in middle-aged relative to younger adults in a button pressing task (Berchicci et al., 2012). This discrepancy might be explained by differences in the nature of the implemented tasks. One key difference lies in the involvement of one limb, often only one finger for the button pressing tasks, versus the involvement of multiple limbs in the interlimb tasks. Also, McEvoy et al. (2001) employed a choice reaction task, while Berchicci et al. (2012) employed a go/no-go task (Berchicci et al., 2012; McEvoy et al., 2001).
Effects of Sleep Deprivation in Military Service Members on Cognitive Performance: A Systematic Review
Published in Military Behavioral Health, 2022
Lyddia A. Petrofsky, Corinne M. Heffernan, Brian T. Gregg, Enrique V. Smith-Forbes
Previous studies on SD and cognitive performance have focused on tests of vigilance such as the PVT, which is based on simple reaction times to a stimulus occurring at random intervals to measure vigilant attention (Lim & Dinges, 2008). Additionally, researchers at the Army Aeromedical Research Lab have explored the relationship between marksmanship and cognition, finding a significant relationship between marksmanship and reaction time among other skills (such as divided attention) required for marksmanship performance (Kelley et al., 2011). Smith et al. (2019) established that sleep deprived SMs display increased reaction times impacting marksmanship performance. This is a noteworthy finding because it accentuates the importance of SMs’ ability to fire a weapon quickly and at the right moment, possibly making a critical difference in becoming a casualty of war. Reaction times have been further studied as a matter of life and death in the medical field. In other cognitively demanding occupations involving life or death scenarios, such as anesthesiology which requires sustained vigilance to quickly respond to multiple critical demands, results have shown slowed reaction times after SD from working on night call duty (Saadat et al., 2017).
Effect of Social Context on Cognitive and Motor Behavior: A Systematic Review
Published in Journal of Motor Behavior, 2022
Maha Mnif, Soufien Chikh, Mohamed Jarraya
In addition, various studies have highlighted the effect of social context on the cognitive behavior of human beings. Particular interest has also been given to the change in reaction time during different social situations. (Quesque et al., 2013, Quesque et al., 2017; Quesque & Coello, 2014). These studies challenge this view by showing that a reaction time can vary depending on the social condition in which it is performed. For example, Quesque and Coello (2014) observed that the reaction time was longer when participants moved a wooden object for the partner than for them. These studies challenge this view by showing that a reaction time can vary depending on the social condition in which it is performed. Besides, the reaction time was shown to be shorter during an action performed with a partner than individually (Quesque et al., 2013, Quesque et al., 2017).