Use of Stimulants to Ameliorate the Effects of Sleep Loss During Sustained Performance

A variety of experimental approaches is presently under investigation to study the impact of stimulant drugs on anticipated decrements of performance due to sleep loss and sustained operations. The drugs have been used either in a preventive (maintenance) paradigm designed to maintain behavior over long periods of time or in a recovery paradigm designed to offset the effects of sleep deprivation and/or sustained performance. Several such studies are reviewed and their results evaluated. Questions concerning theoretical and practical applications are raised, and suggestions for future research are discussed.     

Learning to ignore: Acquisition of sustained attentional suppression

We examined whether the selection mechanisms committed to the suppression of ignored stimuli can be modified by experience to produce a sustained, rather than transient, change in behavior. Subjects repeatedly ignored the shape of stimuli, while attending to their color. On subsequent attention to shape, there was a robust and sustained decrement in performance that was selective to when shape was ignored across multiple-colortarget contexts, relative to a single-color-target context. Thus, amount of time ignored was not sufficient to induce a sustained performance decrement. Moreover, in this group, individual differences in initial color target selection were associated with the subsequent performance decrement when attending to previously ignored stimuli. Accompanying this sustained decrement in performance was a transfer in the locus of suppression from an exemplar (e.g., a circle) to a feature (i.e., shape) level of representation. These data suggest that learning can influence attentional selection by sustained attentional suppression of ignored stimuli.     

Schizotypy and sustained attention: confirming evidence from an adult community sample

Sustained attention deficits represent one of the most robust findings in the study of schizophrenia and schizotypy. However, very little is known about the nature of sustained attention performance and schizotypy in the general adult population. The present study assessed sustained attention performance in a large, normative adult community sample (N = 305) with no history of psychosis using the Continuous Performance Test-identical pairs version (CPT-IP). Associations between overall CPT-IP performance and schizotypal personality disorder features, controlling for the effects of age, sex, and educational level, revealed diminished sensitivity (d', discriminability), and increased random errors were related to increased reality distortion features. These data, drawn from a general population sample, provided support for overall sustained attention deficits as an endophenotype for schizophrenia liability.     

Subjective experience and the attentional lapse: task engagement and disengagement during sustained attention

Three experiments investigated the relationship between subjective experience and attentional lapses during sustained attention. These experiments employed two measures of subjective experience (thought probes and questionnaires) to examine how differences in awareness correspond to variations in both task performance (reaction time and errors) and psycho-physiological measures (heart rate and galvanic skin response). This series of experiments examine these phenomena during the Sustained Attention to Response Task (SART, Robertson, Manly, Adrade, Baddeley, & Yiend, 1997). The results suggest we can dissociate between two components of subjective experience during sustained attention: (A) task unrelated thought which corresponds to an absent minded disengagement from the task and (B) a pre-occupation with one's task performance that seems to be best conceptualised as a strategic attempt to deploy attentional resources in response to a perception of environmental demands which exceed ones ability to perform the task. The implications of these findings for our understanding of how awareness is maintained on task relevant material during periods of sustained attention are discussed.     

A methodological note on evaluating performance in a sustained-attention-to-response task

We evaluated the influence of speed–accuracy trade-offs on performance in the sustained attention to response task (SART), a task often used to evaluate the effectiveness of techniques designed to improve sustained attention. In the present study, we experimentally manipulated response delay in a variation of the SART and found that commission errors, which are commonly used as an index of lapses in sustained attention, were a systematic function of manipulated differences in response delay. Delaying responses to roughly 800 ms after stimulus onset reduced commission errors substantially. We suggest the possibility that any technique that affects response speed will indirectly alter error rates independently of improvements in sustained attention. Investigators therefore need to carefully explore, report, and correct for changes in response speed that accompany improvements in performance or, alternatively, to employ tasks that control for response speed.     

Age-related changes in neural mechanisms of prospective memory

The capability to remember and execute intentions in the future – termed prospective memory (PM) – may be of special significance for older adults to enable successful completion of important activities of daily living. Despite the importance of this cognitive function, mixed findings have been obtained regarding age-related decline in PM, and, currently, there is limited understanding of potential contributing mechanisms. In the current study, older (N=41) and younger adults (N=47) underwent task-functional MRI during performance of PM conditions that encouraged either spontaneous retrieval (Focal) or sustained attentional monitoring (Non-focal) to detect PM targets. Older adults exhibited a reduction in PM-related sustained activity within the anterior prefrontal cortex (aPFC) and associated dorsal frontoparietal cognitive control network, due to an increase in non-specific sustained activation in (no-PM) control blocks (i.e., an age-related compensatory shift). Transient PM-trial specific activity was observed in both age groups within a ventral parietal memory network that included the precuneus. However, within a left posterior inferior parietal node of this network, transient PM-related activity was selectively reduced in older adults during the non-focal condition. These age differences in sustained and transient brain activity statistically mediated age-related declines in PM performance, and were potentially linked via age-related changes in functional connectivity between the aPFC and precuneus. Together, they support an account consistent with the Dual Mechanisms of Control framework, in which age-related PM declines are due to neural mechanisms that support proactive cognitive control processes, such as sustained attentional monitoring, while leaving reactive control mechanisms relatively spared.     

Performance-based and parent ratings of attention in children treated for a brain tumor: The significance of radiation therapy and tumor location on outcome

Children are at increased risk for cognitive difficulties following the diagnosis and treatment of a brain tumor. Radiation therapy (RT) and tumor location are commonly-cited predictors of neurocognitive functioning. Disruptions to foundational neurocognitive processes such as attention, working memory, and processing speed underlie declines on measures of general intellectual functioning. While several studies have examined visual sustained attention in pediatric brain tumor patients, auditory sustained attention has yet to be examined. This study employs a longitudinal design to examine performance-based and parent ratings of attention in children undergoing surgical resection of a brain tumor (n = 29) and treated with (n = 11) or without (n = 18) RT at 6.79 months post-surgery (baseline) and then again at 30.56 months post-surgery (follow-up). The measures include an auditory continuous performance test (CPT) and parent ratings of attention and hyperactivity on a behavior rating scale. Ultimately, children treated with and without RT performed similarly on performance-based and parent ratings of attention. However, the performance on the auditory CPT differed according to tumor location, with children with infratentorial tumors committing more inattention and inhibitory control errors compared to children with supratentorial tumors. Parent ratings did not differ according to tumor location, and parent ratings and auditory sustained attention performance are not significantly correlated. The findings are interpreted in the context of neurocognitive and brain development.     

Neurocognitive functioning in adults with attention-deficit/hyperactivity disorder

The performance of nine adults with attention-deficit/hyperactivity disorder (ADHD) was compared with the performance of 23 normal controls on computerized measures of target orientation, sustained attention, encoding speed, and motor output/response organization to determine the nature of the neurocognitive deficits of adults with ADHD. While the groups' performances on measures of sustained attention and encoding speed did not differ, significant group differences were seen on a task that targeted motor output/response organization. These data suggest that the neurocognitive difficulties of ADHD adults are not related to a primary deficit in sustained attentional functioning. Rather, the deficient information processing in ADHD adults is related to difficulties with motor output/response organization.     

Evidence for a cognitive control network for goal-directed attention in simple sustained attention

The deterioration of performance over time is characteristic for sustained attention tasks. This so-called “performance decrement” is measured by the increase of reaction time (RT) over time. Some behavioural and neurobiological mechanisms of this phenomenon are not yet fully understood. Behaviourally, we examined the increase of RT over time and the inter-individual differences of this performance decrement. On the neurophysiological level, we investigated the task-relevant brain areas where neural activity was modulated by RT and searched for brain areas involved in good performance (i.e. participants with no or moderate performance decrement) as compared to poor performance (i.e. participants with a steep performance decrement). For this purpose, 20 healthy, young subjects performed a carefully designed task for simple sustained attention, namely a low-demanding version of the Rapid Visual Information Processing task. We employed a rapid event-related functional magnetic resonance imaging (fMRI) design. The behavioural results showed a significant increase of RT over time in the whole group, and also revealed that some participants were not as prone to the performance decrement as others. The latter was statistically significant comparing good versus poor performers. Moreover, high BOLD-responses were linked to longer RTs in a task-relevant bilateral fronto-cingulate-insular-parietal network. Among these regions, good performance was associated with significantly higher RT-BOLD correlations in the pre-supplementary motor area (pre-SMA). We concluded that the task-relevant bilateral fronto-cingulate-insular-parietal network was a cognitive control network responsible for goal-directed attention. The pre-SMA in particular might be associated with the performance decrement insofar that good performers could sustain activity in this brain region in order to monitor performance declines and adjust behavioural output.     

Sustaining visual attention in the face of distraction: a novel gradual-onset continuous performance task

Sustained attention is a fundamental aspect of human cognition and has been widely studied in applied and clinical contexts. Despite a growing understanding of how attention varies throughout task performance, moment-to-moment fluctuations are often difficult to assess. In order to better characterize fluctuations in sustained visual attention, in the present study we employed a novel continuous performance task (CPT), the gradual-onset CPT (gradCPT). In the gradCPT, a central face stimulus gradually transitions between individuals at a constant rate (1,200 ms), and participants are instructed to respond to each male face but not to a rare target female face. In the distractor-present version, the background distractors consist of scene images, and in the distractor-absent condition, of phase-scrambled scene images. The results confirmed that the gradCPT taxes sustained attention, as vigilance decrements were observed over the task’s 12-min duration: Participants made more commission errors and showed increasingly variable response latencies (RTs) over time. Participants’ attentional states also fluctuated from moment to moment, with periods of higher RT variability being associated with increased likelihood of errors and greater speed–accuracy trade-offs. In addition, task performance was related to self-reported mindfulness and the propensity for attention lapses in everyday life. The gradCPT is a useful tool for studying both low- and high-frequency fluctuations in sustained visual attention and is sensitive to individual differences in attentional ability.     

Examining the role of emotional valence of mind wandering: All mind wandering is not equal

To evaluate the role of emotional valence on the impact of mind wandering on working memory (WM) and sustained attention, we reanalyzed data from three independently conducted studies that examined the impact of stress on WM (Banks & Boals, 2016; Banks, Welhaf, & Srour, 2015) and sustained attention (Banks, Tartar, & Welhaf, 2014). Across all studies, participants reported the content of their thoughts at random intervals during the WM or sustained attention task. Thought probes in all studies included a core set of response options for task-unrelated thoughts (TUTs) that were negatively, positively, or neutrally emotionally valenced. In line with theories of emotional valenced stimuli on capture of attention, results suggest negatively valenced TUTs, but not positively valenced TUTs, were related to poorer WM and sustained attention in two studies. Neutral TUTs were related to poorer WM but not sustained attention performance. Implications for models of mind wandering are discussed.     

A cognitive tool to diagnose predominantly inattentive ADHD behavior

Poor performance on tests of reading comprehension could be the result of weak word-recognition skills, inconsistent attention (ADD), or a combination of the two. Identifying the source of the reading disability (RD) reliably has been difficult because inconsistent attention interferes with reading and weak word recognition skill makes attention wander. The situation is further complicated by the fact that there are no objective diagnostic tests for ADD (Breggin, 1998; Diller, 1998). We proposed a new model of differential diagnosis of ADHD-I/RD and field-tested its utility in two studies. The new diagnostic procedure utilizes intra-individual differences seen in the performance of at-risk learners on tasks related to reading that vary in the degree of sustained attention required for successful performance. The hypothesis is that children whose attention is inconsistent would perform more poorly on tests such as listening comprehension, which require sustained attention, than on tests such as reading comprehension, which are more tolerant of inattention. Such differences will not be seen in the test scores of children who have only a reading disability because their performance on reading tests is determined more by the difficulty level of the tests than by the sensitivity of the tests to attention. The validity of this new model was evaluated by determining the relationship between differences seen in the scores of tests that differ in their attention requirement and the degree of inconsistency in sustained attention as measured by Conners' CPT. The results of the two studies indicate this to be a viable approach. The results of the second study are presented in this report.     

Feasibility and validity of the structured attention module among economically disadvantaged preschool-age children

Rooted in the theory of attention put forth by Mirsky, Anthony, Duncan, Ahearn, and Kellam (1991), the Structured Attention Module (SAM) is a developmentally sensitive, computer-based performance task designed specifically to assess sustained selective attention among 3- to 6-year-old children. The current study addressed the feasibility and validity of the SAM among 64 economically disadvantaged preschool-age children (mean age = 58 months; 55% female); a population known to be at risk for attention problems and adverse math performance outcomes. Feasibility was demonstrated by high completion rates and strong associations between SAM performance and age. Principal Factor Analysis with rotation produced robust support for a three-factor model (Accuracy, Speed, and Endurance) of SAM performance, which largely corresponded with existing theorized models of selective and sustained attention. Construct validity was evidenced by positive correlations between SAM Composite scores and all three SAM factors and IQ, and between SAM Accuracy and sequential memory. Value-added predictive validity was not confirmed through main effects of SAM on math performance above and beyond age and IQ; however, significant interactions by child sex were observed: Accuracy and Endurance both interacted with child sex to predict math performance. In both cases, the SAM factors predicted math performance more strongly for girls than for boys. There were no overall sex differences in SAM performance. In sum, the current findings suggest that interindividual variation in sustained selective attention, and potentially other aspects of attention and executive function, among young, high-risk children can be captured validly with developmentally sensitive measures.     

Motivational influences on cognitive control: Behavior,brain activation,and individual differences

What changes in brain activity are associated with changes in motivational state? The present study addressed this question by having participants perform a cognitive task (AX variant of the Continuous Performance Test; AX-CPT) under three different blocked motivational conditions (reward-incentive, penalty-incentive, and baseline). Behavioral data showed that the incentive conditions modulated task performance, potentially by altering participants’ cognitive control strategy. Neuroimaging data indicated that the reward condition was associated with a sustained increase in a primarily right-lateralized network that included parietal and prefrontal cortex. Additionally, individual differences were observed, such that activation in both reward-related brain regions and frontopolar cortex was linked to the degree of motivation-induced performance enhancement and to motivation-related personality variables. These results suggest that changes in motivational state may modulate performance through sustained activity in cognitive control regions and that the effect of incentives may be affected by the personalities of the participants.     

Sitting with it: An investigation of the relationship between trait mindfulness and sustained attention

BackgroundSustaining attention for extended periods of time is associated with negative affect and this increase in negative affect is related to poorer task performance. Trait mindfulness has been shown to be associated with better sustained attention performance. This may be because trait mindfulness is associated with better attention ability or better emotion regulation ability.AimsThe present research aims to replicate previous findings and better understand why trait mindfulness is associated with better sustained attention performance.MethodParticipants responded to self-report questionnaires assessing their trait mindfulness, attentional control, and experiential avoidance. Next, participants performed a sustained attention task, during which they also reported their subjective feelings of discomfort and boredom. Finally, participants reported their retrospective discomfort and boredom after the task.ResultsWe replicated and extended previous findings by showing that the relationship between trait mindfulness and sustained attention performance was mediated by negative affect experienced during the task. Moreover, the correlation between trait mindfulness and sustained attention disappeared when controlling for experiential avoidance, but remined when controlling for attention control.ConclusionOur results suggest that trait mindfulness is associated with sustained attention because of enhanced emotion regulation and that enhancing affective regulation would be an effective strategy for improving sustained attention performance.     

The Relationship Between Measures of Cognitive Attention and Behavioral Ratings of Attention in Typically Developing Children

In the present study, we explored the relation between performance on cognitive measures of attention (selection, sustained, and control) and behavioral ratings of inattention and hyperactivity in a sample of typically developing children aged 3 to 7 years. We also examined the influence of chronological age and IQ on both task performance and behavior ratings. Four well-documented attention paradigms were employed, the Visearch (single-target search) task as a measure of selective attention, the Continuous Performance Test (CPT) as a measure of sustained attention, the Day-Night task as a measure of response inhibition, and the Visearch (dual-target search) task as a measure of inhibitory control. The Conners' Rating Scales (Cognitive/Inattention and Hyperactivity subscales) were used to allow for a finer tuned comparison of cognitive performance as related to inattentive behaviors versus hyperactive behaviors. Findings indicate that accuracy and speed in the Visearch dual search task were the most sensitive measures relating respectively to inattentive and hyperactive rated behaviors.     

Sustained attention and related perceptuomotor functions

The present study examined the relationship between two measures of sustained attention on the Continuous Performance Test (reaction time and omission errors) and several performance measures on neuropsychological tests. Analysis suggests that sustained attention as measured by processing speed predicts performance on neuropsychological measures of relatively greater complexity and that the Stroop test, which requires maintaining steady focus on a changing stimulus field, may be more sensitive to lapses in attention than other neuropsychological tests.     

Investigating sustained attention ability in the elderly by using two different approaches: Inhibiting ongoing behavior versus responding on rare occasions

Previous studies on sustained attention ability in the elderly produced inconsistent results. The aim of this study was to evaluate sustained attention performance in younger and older individuals by using, in a within-subjects design, two versions of the same task (the sustained attention to response task, SART) in which only in the response mode differed: in a traditionally formatted task (TFT), subjects had to respond to rare targets, and in a Go/No-Go task they had to withhold response to rare targets. Results showed that in the TFT SART only the older group exhibited a vigilance decrement. On the contrary, only young individuals showed a vigilance decrement in the Go/No-Go SART. These results showed that older individuals, who also reported less mind wandering and a higher level of motivation, exhibited preserved sustained attention ability in the Go/No-Go SART, which could be explained by increased engagement of cognitive control mechanisms in this population. The discrepancy in performance depending on the approach used also underlines the need for further studies on the nature of attention failures and their underlying mechanisms.     

Absent-mindedness: Lapses of conscious awareness and everyday cognitive failures

A brief self-report scale was developed to assess everyday performance failures arising directly or primarily from brief failures of sustained attention (attention-related cognitive errors-ARCES). The ARCES was found to be associated with a more direct measure of propensity to attention lapses (Mindful Attention Awareness Scale--MAAS) and to errors on an existing behavioral measure of sustained attention (Sustained Attention to Response Task--SART). Although the ARCES and MAAS were highly correlated, structural modelling revealed the ARCES was more directly related to SART errors and the MAAS to SART RTs, which have been hypothesized to directly reflect the lapses of attention that lead to SART errors. Thus, the MAAS and SART RTs appear to directly reflect attention lapses, whereas the ARCES and SART errors reflect the mistakes these lapses are thought to cause. Boredom proneness was also assessed by the BPS, as a separate consequence of a propensity to attention lapses. Although the ARCES was significantly associated with the BPS, this association was entirely accounted for by the MAAS, suggesting that performance errors and boredom are separate consequences of lapses in attention. A tendency to even extraordinarily brief attention lapses on the order of milliseconds may have far-reaching consequences not only for safe and efficient task performance but also for sustaining the motivation to persist in and enjoy these tasks.     

Interactions between endogenous and exogenous attention during vigilance

The ability to remain vigilant over long periods of time is critical for many everyday tasks, but controlled studies of visual sustained attention show that performance declines over time when observers are required to respond to rare stimulus events (targets) occurring in a sequence of standard stimulus events (nontargets). When target discrimination is perceptually difficult, this vigilance decrement manifests as a decline in perceptual sensitivity. We examined whether sudden-onset stimuli could act as exogenous attentional cues to improve sensitivity during a traditional sustained attention task. Sudden-onset cues presented immediately before each stimulus attenuated the sensitivity decrement, but only when stimulus timing (the interstimulus interval [ISI]) was constant. When stimulus timing was variable, exogenous cues increased overall sensitivity but did not prevent performance decline. Finally, independent of the effects of sudden onsets, a constant ISI improved vigilance performance. Our results demonstrate that exogenous attention enhances perceptual sensitivity during vigilance performance, but that this effect is dependent on observers’ being able to predict the timing of stimulus events. Such a result indicates a strong interaction between endogenous and exogenous attention during vigilance. We relate our findings to a resource model of vigilance, as well as to theories of endogenous and exogenous attention over short time periods.