Information processing, speed

Cognitive effects Human nonsmokers Administration of nicotine to tobacco nonusers produces small cognitive enhancements. Studies in tobacco nonusers have primarily measured attention, information processing speed, and memory. Nicotine improves perceptual speed, choice reaction time, and digit recall (Stough et al. 1995 Le Houezec et al. 1994 Foulds et al. 1996). Improvements also occur in digit symbol substitution and continuous performance tests without reducing accuracy (Petrie and Deary 1989 Levin et al. 1998). 

Sergejew, and T. Rolfe. The effects of cannabis on information-processing speed. Addict Behav 2004 29(6) 1213-1219. 

Response accuracy reflects the animal s capacity to remember the lever previously presented and therefore represents a measure of short-term memory. Simple reaction times reflect the animal s rapidity to respond to an unpredictable spatial stimulus and therefore represent a measure of attention. Choice reaction times reflect the animal s rapidity to choose between two levers and therefore represent a measure of decision taking or information processing speed. Performance on all parameters improves over the acquisition period and therefore indicates the animal s capacity to learn the new task. 

Fig. 14. Effects of diazepam and scopolamine on the 3 parameters measured during the acquisition of a delayed alternation task in the rat (mean performance over 10 sessions). Note that both diazepam and scopolamine significantly decrease the number of correct responses (impairment of learning/memory). Diazepam has no effect on simple reaction times whereas scopolamine significantly increases it (impairment of attention). Diazepam significantly decreases choice reaction times whereas choice reaction times are clearly increased by scopolamine. The increased choice reaction times with scopolamine probably reflect an impairment of information processing speed, whereas the decrease observed with diazepam probably reflects the disinhibitory effects of diazepam.

Severity of white matter change, brain atrophy and the presence of infarction are associated with decline in information-processing speed and executive function (Prins et al. 2005). Presence of subcortical hyperintensities is associated with cognitive impairment following clinical stroke secondary to lacunar infarction (Mok et al. 2005 Grau-Olivares et al. 2007). 

An example of an inferential task-analysis approach that is relatively new is nonlinear causal resource analysis (NCRA) [Kondraske, 1998,1999 Kondraske et al., 1997]. This method was motivated by human performance analysis situations where direct analysis is not possible (e.g., determination of the amount of visual information-processing speed required to drive safely on a highway). Quantitative task demands, in terms of performance variables that characterize the involved subsystems, are inferred from a population data set that includes measures of subsystem performance, resource availabilities (e.g., speed, accuracy, etc.), and overall performance on the task in question. This method is based on the simple observation that the individual with the least amount of the given resource (i.e., the lowest performance capacity) who is still able to accomplish a given goal (i.e., achieve a given level of performance in the specified high-level task) provides the key clue. That amount of availability is used to infer the amount of demand imposed by the task. 

Information processing speed = l/(8-choice reaction time)... 

Information-Processing Speed Information-Processing Accuracy and Speed-Accuracy Combinations Memory... 

A representative instrument [Kondraske et al., 1984 Kondraske, 1990] is illustrated in Figure 78.4. This device incorporates 8 LEDs and 15 high-speed touch sensors ( home, A1-A8 and B1-B6) and a dedicated internal microprocessor to measure an array of different performance capacities associated with information-processing. Measures at the most basic hierarchical level (visual information-processing speed, visual-spatial memory capacity, visual attention span, etc.) and intermediate level (coordination tasks involving different sets of more basic functional units) are included. 

For example, visual-upper extremity information-processing speed is measured in a paradigm whereby the test subject first places his/her hand on the home plate. A random time after an audible warning... 

Visual-upper extremity information processing speed Visual attention span Visual-spatial memory capacity Visual-numerical memory capacity... 

Visual information processing speed Visual-spatial memory capacity Postural stability... 

Visual upper extremity information procession speed Bond Lader visual analog scale... 

Visual upper extremity information processing speed Upper extremity random reach movement speed Index finger (proximal intercarpal phalangeal joint), flexion extension speed... 

The paradigm for measuring information-processing speed is commonly referred to as a reaction time test since the elapsed time (i.e., the processing time) between the onset of a given stimulus and the occurrence of a prescribed response is the basic measurable quantity. To obtain a processing speed measure, the stimulus content in bits, chunks, or simply stimuli is divided by the processing... 

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