Sustained attention tests

Lawrence and colleagues (2002) explored the neural substrates of nicotine effects on sustained attention using the rapid visual information processing (RVIP) task. Smokers (n = 15) received either placebo or 21-mg transdermal nicotine patch prior to testing. Matched nonsmokers (n = 14) were tested under similar conditions, but did not receive a nicotine patch. Relative to the placebo condition, the smokers in the nicotine condition demonstrated improved task performance and increased neural activity in the parietal and occipital cortices, the thalamus and caudate, and decreased activity in left frontal, anterior and posterior cingulate, insula, and left parahippocampal regions (see Fig. 3). As noted by the authors, previous studies... 

Attentional or cognitive impairments have also been observed in rodent models of nicotine withdrawal. These include impaired performance of a test of sustained attention (Shoaib and Bizarro 2005), disrupted contextual fear conditioning (Davis and Gould 2007 Davis et al. 2005), disrupted operant behaviors (Vann et al. 2006), and decreased prepulse inhibition, a test of selective attention (Semenova et al. 2003). 

As discussed previously, results of studies conducted with nicotine-deprived smokers are difficult to interpret. Without pre-deprivation baseline data, which few studies report, it is difficult to conclude whether nicotine reversed deprivation-induced deficits or enhanced performance beyond that observed in the nondeprived state. In general, however, nicotine and smoking at least reversed deprivation-induced deficits in certain abilities in abstinent smokers, but such beneficial effects have not been observed consistently across a range of performance measures. For example, about half of the studies that measured sustained attention and memory reported a positive effect of nicotine however, the effects were limited to some subjects or one aspect of test performance. 

Consistent with the other types of attention, benzodiazepines impair performance in tests of sustained attention or vigilance.14 143 145 There is no evidence that benzodiazepines exacerbate the vigilance decrement normally observed during prolonged, tedious tests. The impairment caused by benzodiazepines in tests of sustained attention is not secondary to sedation, but rather a direct effect on perceptual sensitivity, resulting in decreased hits and increased response time in detecting stimulus targets. 

Marijuana also impairs sustained attention. In a 30-min vigilance task, hashish users exhibited more false alarms than non-using control subjects 257 This finding is consistent with the observation that the impairing effects of marijuana on sustained attention are most evident in tests that last 30 to 60 min tests with durations of 10 min are not adversely affected by marijuana.11... 

Another important consideration in the selection of an impairment testing system is whether norm-based decision criteria will be used to evaluate readiness to perform an assignment and, if so, whether such norms are currently available. It is important that such norms address both decrements and improvements in performance, as improved performance may also signal the influence of a risk factor. For example, stimulant medications may have minimal effect on performance of most tasks, but under test conditions requiring sustained attention, enhanced performance may be noted.14 These same doses of stimulant medication may have important implications for more complex dimensions of human behavior,15 16 so the detection of enhanced performance may signal an increased risk for detrimental effects on other more complex behaviors that are not directly measured during testing. 

Although the effects of caffeine on some aspects of performance may be difficult to establish, the impact of this compound on tasks requiring vigilance or sustained attention is clearer. Lieberman et al. (110) evaluated the impact of 32-, 64-, 128-, and 256-mg doses of caffeine on a four-choice visual reaction time test (10 min), a continuous-performance task (variable duration), and the Wilkinson auditory vigilance test (1 hr). Results indicated that every dose of caffeine improved four-... 

The effect of intrauterine cocaine exposure on visual attention, cognition, and behavior has been investigated in 14 cocaine-exposed children and 20 controls aged 14-60 months (288). The cocaine-exposed children were slower in tests of disengagement and sustained attention. They also had greater difficulties in behavioral regulation. 

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