Sustained Selective Attention Research Articles

Closing-in behaviour in preschool children

Many pre-school children show closing-in behaviour (CIB) in graphic copying tasks: a tendency to place their copy abnormally close to or even on top of the model. Similar phenomena have been studied in patients with dementia, though it is unclear whether the superficial similarities between CIB in development and dementia reflect common underlying cognitive mechanisms. The aim of the present study was to investigate the cognitive functions involved in CIB in pre-school children. Forty-one children (3-5 years) were assessed for CIB, and completed a neuropsychological battery targeting visuospatial abilities, short term memory (verbal and spatial) and attention (sustained attention, selective attention and attention switching). Binary logistic regression found that performance on the attention subtests was the best unique predictor of CIB. A second analysis, in which the three attention subtests were entered as separate predictors, suggested that attention switching ability was most strongly related to CIB. These results support the view that CIB in children reflects inadequate attentional control. The convergence of these results with similar observations in patients with dementia further suggests that similar cognitive factors underlie CIB in these two populations.

Impact of Neonatal Thyroid Hormone Insufficiency and Medical Morbidity on Infant Neurodevelopment and Attention Following Preterm Birth

Infants born preterm are at risk of both transiently reduced thyroid hormone levels and impaired neurocognitive development, including attention deficits. The objective of this study was to examine the effects of reduced thyroid hormone levels on general neurodevelopment and attention at 3 months corrected age. Sixty-four infants born 24 to 35 weeks gestation were stratified into four gestational age groups: Group A, 23-26 weeks (n = 10); Group B, 27-29 weeks (n = 23); Group C, 30-32 weeks (n = 20); Group D, 33-35 weeks (n = 11). Controls were 33 healthy infants born full-term (Group E). In preterm only, free thyroxine (FT(4)), triiodothyronine (T(3)), and thyrotropin (TSH) were measured at 2 and 4 weeks of life and at 40 weeks postconceptional age. At 3 months corrected age, all infants were assessed with the Bayley Scales of Infant Development-Second Edition (BSID-II), from which both mental development index (MDI) and psychomotor development index (PDI) scores and four indices of attention were derived: sustained attention, selective attention, attention shift, and total attention. Gestational age-stratified preterm groups differed significantly in T(3) and FT(4) levels at 2 and 4 weeks of life in infants born less than 27 weeks gestation. Preterm infants overall scored significantly below full-term on BSID-II MDI and PDI, selective, sustained, and total attention scales. In the preterm group, FT(4) levels were positively associated with PDI and selective, sustained, and total attention. Reduced levels of thyroid hormone in the neonatal period in preterm infants are associated with a reduced neurocognitive outcome in the attention domain at 3 months corrected age.

Using fMRI to distinguish components of the multiple object tracking task

Multiple object tracking (MOT) has proven to be a powerful technique for studying sustained selective attention. However, surprisingly little is known about its underlying neural mechanisms. Previous fMRI investigations have identified several brain areas thought to be involved in MOT, but there were disagreements between the studies, none distinguished between the act of tracking targets and the act of attending targets, and none attempted to determine which of these brain areas interact with each other. Here we address these three issues. First, using more observers and a random effects analysis, we show that some of the previously identified areas may not play a specific role in MOT. Second, we show that the frontal eye fields (FEF), the anterior intraparietal sulcus (AIPS), the superior parietal lobule (SPL), the posterior intraparietal sulcus (PIPS) and the human motion area (MT+) are differentially activated by the act of tracking, as distinguished from the act of attention. Finally, by using an algorithm modified from the computer science literature, we were able to map the interactions between these brain areas.

Neural mechanisms of intermodal sustained selective attention with concurrently presented auditory and visual stimuli

We investigated intermodal attention effects on the auditory steady-state response (ASSR) and the steady-state visual evoked potential (SSVEP). For this purpose, 40-Hz amplitude-modulated tones and a stream of flickering (7.5 Hz) random letters were presented concurrently. By means of an auditory or visual target detection task, participants’ attention was directed to the respective modality for several seconds. Attention to the auditory stream led to a significant enhancement of the ASSR compared to when the visual stream was attended. This attentional modulation was located mainly in the right superior temporal gyrus. Vice versa, attention to the visual stream especially increased the second harmonic response of the SSVEP. This modulation was focused in the inferior occipital and lateral occipitotemporal gyrus of both hemispheres. To the best of our knowledge, this is the first demonstration of amplitude modulation of the ASSR and the SSVEP by intermodal sustained attention. Our results open a new avenue of research to understand the basic neural mechanisms of intermodal attention in the human brain.

Sustained Selective Attention Skills of Preschool Children With Specific Language Impairment: Evidence for Separate Attentional Capacities

The present study was designed to investigate the performance of preschool children with specific language impairment (SLI) and their typically developing (TD) peers on sustained selective attention tasks. This study included 23 children diagnosed with SLI and 23 TD children matched for age, gender, and maternal education level. The children's sustained selective attention skills were assessed with different types of stimuli (visual, nonverbal-auditory, linguistic) under 2 attentional load conditions (high, low) using computerized tasks. A mixed design was used to compare children across groups and performance across tasks. The SLI participants exhibited poorer performance than their peers on the sustained selective attention tasks presented in the auditory modality (linguistic and nonverbal-auditory) under the high attentional load conditions. Performance was comparable with their peers under the low attentional load conditions. The SLI group exhibited similar performance to their peers on the visual tasks regardless of attentional load. These results support the notion of attention difficulties in preschool children with SLI and suggest separate attentional capacities for different stimulus modalities.

VISUAL SEARCH ATTENTION AND EXECUTIVE FUNCTION IN CHINESE CHILDREN WITH WILLIAMS SYNDROME

INTRODUCTION: Williams syndrome (WS) is a rare neurodevelopmental disorder that is caused by a hemizygous deletion on chromosome 7q11.23. The interest of WS to neurocognitive scientists stems from the uneven profiles of cognitive abilities, with spatial cognition seriously impaired and language and face processing relatively proficient. We know relatively little about the visual search attention and executive function in children with WS. OBJECTIVE: The objective of this study was to examine the nature of visual search attention and executive function in children with WS, compared with children with Down syndrome (DS), healthy chronological age–matched control subjects (CA), and healthy mental age–matched control subjects (MA). METHODS: A total of 142 children were tested: 21 with WS, 25 with DS, 45 CA, and 41 MA. MA were matched to the children with WS and DS using the Peabody Picture Vocabulary Test. All participants were assessed on a set of computerized visual search tasks and Wilding Monster Sorting Test using a touch-screen. RESULTS: The results showed that selective attention, switch, and sustained attention of children with WS all are less developed. Children with WS produced a large number of shape errors, and they also confused shape distractors with targets more than the other groups. Children with WS exhibited poorer executive performance as compared with both groups of typical children. They produced more repetitive errors than did children with DS. CONCLUSIONS: These findings reveal distinct visual search deficits and atypically developing executive function in children with WS.

Attentional functions in children and adolescents with attention-deficit/hyperactivity disorder with and without comorbid tic disorder

Although the coexistence of attention-deficit/hyperactivity disorder (ADHD) and tic disorder (TD) is common, the nature of association is yet not fully understood. Thus, the aim of the present study was to explore attentional dysfunction in children with pure ADHD compared to children with comorbid ADHD + TD. Three groups of 20 children each, aged 8-15 years with either ADHD, ADHD + chronic tic disorder or Tourette syndrome (ADHD + TD) and a healthy control group were compared in their performance on three computerized attention tasks. Tasks of sustained attention, selective attention and interference control were employed. In addition, parental ratings of ADHD symptom severity and behaviour problems were obtained. Both clinical groups were rated as equally inattentive, however, externalising symptoms were more severe in the ADHD group. Objective measures of attentional performance revealed differences between the groups: whereas the ADHD group was markedly impaired in sustaining attention and selective attention/inhibitory control, the ADHD + TD group only showed marginal deficits in selective attention/inhibitory control. Possible explanations for the superior performance of the comorbid group are discussed: In particular, the results may indicate that in some patients, the tic disorder produces behavioural symptoms of ADHD, but not the broad neurocognitive deficits that usually are associated with ADHD. Alternatively, compensatory neural mechanisms of TD patients may result in a better neuropsychological performance of comorbid patients relative to patients suffering from pure ADHD.

Do antisaccade deficits in schizophrenia provide evidence of a specific inhibitory function?

Despite its inhibitory control requirements, antisaccade deficits have been consistently associated with working memory impairments in schizophrenia. We investigated whether variance in antisaccade performance could be better accounted for in terms of a specific inhibitory function. We assessed 48 clinically stable out-patients with schizophrenia on an antisaccade task, as well as on measures of spatial and verbal working memory, sustained selective attention, and a simple motoric go/no-go measure of response inhibition. In a stepwise multiple regression analysis, go/no-go task performance accounted for a considerably greater percentage of variance in antisaccade performance (25.3%) than either working memory (8.4%) or sustained selective attention task (9.1%). We conclude that antisaccade deficits in schizophrenia appear to be better understood in terms of a specific deficit of inhibitory control than in terms of more general difficulties with context maintenance or goal neglect.

Comparing attentional skills in children with acquired and developmental central nervous system disorders

Attentional impairments in children occur in the context of both developmental and acquired disorders involving the central nervous system (CNS) and may have implications for ongoing development, potentially impeding cognitive, educational, and behavioral functions. Using a continuous performance paradigm (CPT), this study compared attentional profiles of children with developmental and acquired conditions impacting on the CNS: (i) attention deficit-hyperactivity disorder (ADHD: n=27); (ii) moderate traumatic brain injury (TBI: n=41); (iii) acute lymphoblastic leukemia (n=31); and (iv) insulin-dependent diabetes mellitus (n=39). A healthy control group (n=46) was also examined. Groups were compared on measures of sustained attention, selective attention, and response inhibition. In addition, measures of performance variability and deterioration and processing speed were examined. Results showed that children with ADHD exhibited global and severe attentional impairments in contrast to all other groups. Children with moderate TBI displayed mild attentional difficulties, restricted to selective and sustained attention domains. In conclusion, although CPT parameters differentiated the ADHD group from all others, a disorder-specific profile was not observed.

Are deficits in executive sub-processes simply reflecting more general cognitive decline in schizophrenia?

Background Schizophrenia is associated with both global and specific cognitive deficits. We sought to investigate whether deficits in executive subcomponents differed in their relationship to global cognitive impairments. Method 95 patients were classified according to pre-morbid and current general cognitive ability as having either (a) intact pre-morbid and current general cognitive ability; (b) intact pre-morbid but deteriorated current ability, and (c) deteriorated both pre-morbid and current cognitive ability. All patients completed measures of verbal and spatial working memory, sustained selective attention, attentional set sifting, and inhibitory control. Results Deficits on both measures of working memory were associated with general cognitive ability. None of the attentional control deficits observed were associated with general ability. Further, spatial working memory deficits were also associated with more severe negative symptoms. Conclusions These results provide further evidence of the discreet nature of attentional deficits in schizophrenia. By contrast, this study suggests that working memory deficits may to some extent index more general cognitive decline. Awareness of such overlap is important for schizophrenia genetics studies where working memory measures has been used to index supposedly discreet aspects of cognitive dysfunction.

Neural substrates for dividing and focusing attention between simultaneous auditory and visual events

With information constantly bombarding the human sensory systems, how is it that we attend to behaviorally relevant information? The present study examined the behavioral and neural bases of attending to one sense while ignoring another sense (bimodal selective attention) contrasted with attending simultaneously to two senses (bimodal divided attention). In a functional magnetic resonance imaging (fMRI) study, subjects simultaneously heard novel melodies and viewed geometric shapes. They were instructed to actively attend to only one or to both senses (selective or divided attention) or as a baseline condition, passively observe both (bimodal passive). Memory tests for both attended and unattended stimuli validated that subjects were following the attention instructions. Selective attention led to increased activity in relevant sensory cortices while simultaneously leading to decreased activity in irrelevant sensory cortices. The divided attention instruction did not lead to a global increase in sensory cortex activity compared to the bimodal passive baseline condition. However, divided attention did recruit heteromodal areas in the left dorsolateral prefrontal cortex, while selective attention did not recruit any frontal areas. We propose that sustained selective and divided bimodal attention were achieved via distinct neural processes. Selective attention was achieved primarily via modulation of the sensory cortices. Divided attention was achieved for most individuals via recruitment of the middle-dorsolateral prefrontal cortex. However, there was also a trade-off between activity in posterior-dorsolateral prefrontal cortex and sensory regions, such that individuals who demonstrated the best performance during divided attention also showed the greatest recruitment of sensory cortices.

Selective auditory attention in 3- to 5-year-old children: An event-related potential study

Behavioral and electrophysiological evidence suggests that the development of selective attention extends over the first two decades of life. However, much of this research may underestimate the attention abilities of young children. By providing strong, redundant attention cues, we show that sustained endogenous selective attention has similar effects on ERP indices of auditory processing in adults and children as young as 3 years old. All participants were cued to selectively attend to one of two simultaneously presented stories that differed in location (left/right), voice (male/female), and content. The morphology of the ERP waveforms elicited by probes embedded in the stories was very different for adults, who showed a typical positive-negative-positive pattern in the 300 ms after probe onset, and children, who showed a single broad positivity during this epoch. However, for 3- to 5-year-olds, 6- to 8-year-olds, and adults, probes in the attended story elicited larger amplitude ERPs beginning around 100 ms after probe onset. This attentional modulation of exogenously driven components was longer in duration for the youngest children. In addition, attended linguistic probes elicited a larger negativity 300–500 ms for all groups, indicative of additional attentional processing. These data show that with adequate cues, even children as young as 3 years old can selectively attend to one auditory stream while ignoring another and that doing so alters auditory sensory processing at an early stage. Furthermore, they suggest that the neural mechanisms by which selective attention affects auditory processing are remarkably adult-like by this age.

The effects of combined caffeine and glucose drinks on attention in the human brain

The objective of this research was to measure the effects of energising drinks containing caffeine and glucose, upon mental activity during sustained selective attention. Non-invasive electrophysiological brain recordings were made during a behavioural study of selective attention in which participants received either energising or placebo drinks. We tested specifically whether energising drinks have significant effects upon behavioural measures of performance during a task requiring sustained visual selective attention, as well as on accompanying components of the event-related potential (ERPs) related to information processing in the brain. Forty healthy volunteers were blindly assigned to receive either the energising drink or a similar-tasting placebo drink. The behavioural task involved identifying predefined target stimulus among rapidly presented streams of peripheral visual stimuli, and making speeded motor responses to this stimulus. During task performance, accuracy, reaction times and ongoing brain activity were stored for analysis. The energising drink enhanced behavioural performance both in terms of accuracy and speed of reactions. The energising drink also had significant effects upon the event-related potentials. Effects started from the enhancement of the earliest components (C1/P1), reflecting early visual cortical processing in the energising-drink group relative to the placebo group over the contralateral scalp. The later N1, N2 and P3 components related to decision-making and responses were also modulated by the energising drink. Energising drinks containing caffeine and glucose can enhance behavioural performance during demanding tasks requiring selective attention. The behavioural benefits are coupled to direct effects upon neural information processing.

Effects of Methylphenidate on Attention Skills in Children With Attention Deficit/Hyperactivity Disorder

AbstractThis study aimed to investigate the effects of methylphenidate on children with Attention Deficit Hyperactivity Disorder (ADHD). The study employed a conceptual framework of attention, consistent with contemporary theory, and including the following components: sustained attention, selective attention, divided attention, shifting attention, and speed of information processing. Fifteen children (12 boys and 3 girls) of normal intelligence, with a diagnosis of ADHD according to the DSM-IV criteria, and ranging in age from 8 to 11 years participated in the study. Children's attentional abilities were evaluated using the Test of Everyday Attention for Children (TEA-Ch: Manly, Roberston, Anderson, & Nimmo-Smith, 1999). A double-blind counterbalanced repeated-measures design approach was employed to tap on–off medication effects, and deviations from normal. Results showed that comparisons between on–off medication conditions generally detected few differences with respect to sustained and selective attention measures and simple processing speed. In contrast, for higher-level attention domains, including shifting and divided attention, children on medication demonstrated a speed–accuracy trade-off, exhibiting greater accuracy, but slower completion times. When data from the ADHD group were compared to controls a consistent pattern emerged, with children with ADHD in the medication condition being more accurate across all attention domains on all measures. While these children also tended to record slower completion times, group differences and effect sizes were of smaller magnitude. The findings of this study suggest a possible speed–accuracy trade-off effect for children with ADHD on medication.

Age-related decrements in performance on a brief continuous performance test

Research has revealed age-related decrements in performance on a variety of attention-related tasks, including sustained attention, selective attention, and inhibition tasks (e.g., [Armstrong, C. (1997). Selective versus sustained attention: A continuous performance test revisited. Clinical Neuropsychologist, 11(1), 18–33; Chao, L. L. & Knight, R. T. (1997). Prefrontal deficits in attention and inhibitory control with aging. Cerebral Cortex, 7(1), 63–69; Deaton, J. E., & Parasuraman, R. (1993). Sensory and cognitive vigilance: Effects of age on performance and subjective workload. Human Performance, 6(1), 71–97]). The continuous performance test (CPT) is a well-recognized measure of sustained attention and impulsivity [Riccio, C. A., Reynolds, C. R., & Lowe, P. (2001). Clinical applications of continuous performance tests: Measuring attention and impulsive responding in children and adults. New York: John Wiley & Sons, Inc.]. In the following study, the influence of age on CPT performance was assessed. Thirty-two healthy adults (age 19–82) completed a brief K–A version of the CPT under “clear” and “noisy” trial conditions. Under both conditions, participants’ accuracy on the CPT task decreased with age. In both conditions, the number of commission errors (including false alarms) increased significantly as age increased. This relationship differed with omission errors, as age accounted for a significant proportion of variance in omission errors under the noisy condition alone. Overall, this study provides evidence for age-related differences in performance on a brief CPT, particularly for deficits in selective response inhibition.

The influence of sustained selective attention on stimulus selectivity in macaque visual area MT.

Remarkable alterations of perception during long-lasting attentional processes have been described in several recent studies. Although these findings have gained much interest, almost nothing is known about the modulation of neuronal responses during sustained attention. Therefore, we investigated the effect of prolonged selective attention on neuronal feature selectivity. Awake macaque monkeys were trained to perform a motion-tracking task that required attending one of two simultaneously presented moving bars for up to 15 sec. Extracellular recordings were obtained from neurons in macaque motion-sensitive middle temporal visual area (MT/V5). Under conditions of attention, we found high and constant direction selectivity over time. This was expressed by a strong and persistent response contrast between presentations of preferred and nonpreferred stimuli in successive motion cycles. With attention directed to another moving bar, neuronal responses to the behaviorally irrelevant stimulus became continuously less specific for the direction of motion. In particular, increasingly higher firing rates for motion in null direction caused a strong reduction of direction selectivity, which further increased with enhanced proximity between target and distracter bar. A passive condition experiment revealed that this reduction occurred only when motion remained the behaviorally relevant feature but disappeared when attention was withdrawn from this feature domain. Thus, sustained attention seems to stabilize direction selectivity of neurons in area MT against a time and competition-dependent degradation, whereas nonattended objects suffer from a reduced neuronal representation.

Selective spatial attention to left or right hand flutter sensation modulates the steady-state somatosensory evoked potential

Steady-state somatosensory evoked potentials (SSSEPs) were recorded from the scalp of human subjects elicited by 20 and 26 Hz mechanical vibrations applied simultaneously to the index finger of the left (20 Hz) and right hand (26 Hz). Subjects were instructed to attend to the flutter vibration at one finger while ignoring the other finger and to detect rare target events at the to-be-attended finger. The amplitude of the frequency coded SSSEP elicited by the attended vibration was significantly enlarged when attention was focused at the respective finger. This amplitude enhancement with attention was most prominent over fronto-central electrode locations contralateral to the attended finger. This is the first report to show the attentional modulation of the SSSEP amplitude in humans, suggesting an enhancement of neural responses in the sense of flutter with attention. The findings will open a new approach for studying the neural mechanisms of sustained selective attention in somatosensation.

The relationship between visual-perception and attention in Chinese with schizophrenia

Previous studies suggest possible visual-perceptual deficits associated with schizophrenia, and co-existing impairments in attention and visual-perceptual function in people with schizophrenia. This study examines if people with schizophrenia show visual-perceptual difficulty and whether different components of attention, namely sustained attention, selective attention, switching attention and attentional control processing, relate to the visual-perceptual function of people with schizophrenia differently. A total of 94 participants voluntarily participated in this study: 47 of them were diagnosed with schizophrenia and 47 were normal controls. Visual-perceptual abilities were measured by the Hooper Visual Organization Test (HVOT) for visual organization ability and the Judgment of Line Orientation Test (JLOT) for spatial perception and orientation. Tests for measuring different components of attention were also administered. We observed that our clinical participants performed significantly poorer in both the HVOT and the JLOT. We further noticed that nonverbal intelligence had a significant influence on our participants' performance in these two administered tests. Regarding the relationship between attention and visual-perceptual function, our findings indicated that such a relationship existed only among our clinical participants, not the normal controls. The attention control process significantly predicted the performance in the HVOT and switching attention efficiency significantly predicted the performance in the JLOT.

Selective spatial attention to left or right hand flutter sensation modulates the steady-state somatosensory evoked potential

Steady-state somatosensory evoked potentials (SSSEPs) were recorded from the scalp of human subjects elicited by 20 and 26 Hz mechanical vibrations applied simultaneously to the index finger of the left (20 Hz) and right hand (26 Hz). Subjects were instructed to attend to the flutter vibration at one finger while ignoring the other finger and to detect rare target events at the to-be-attended finger. The amplitude of the frequency coded SSSEP elicited by the attended vibration was significantly enlarged when attention was focused at the respective finger. This amplitude enhancement with attention was most prominent over fronto-central electrode locations contralateral to the attended finger. This is the first report to show the attentional modulation of the SSSEP amplitude in humans, suggesting an enhancement of neural responses in the sense of flutter with attention. The findings will open a new approach for studying the neural mechanisms of sustained selective attention in somatosensation.

Attention Deficits in Patients with Persisting Postconcussive Complaints: A General Deficit or Specific Component Deficit?

This study aimed to examine attentional performance in patients with persisting postconcussive complaints, using a multi-componential perspective. Comparisons of attentional performances of 92 patients with postconcussive complaints and 86 normal controls were conducted using tests of sustained attention (Sustained Attention to Response Task; Digit Backward Span), selective attention (Stroop Word-Color Test; Color Trails Test), divided attention (Paced Auditory Serial Addition Test; Symbol Digit Modalities Test), and attentional control processing (Six Elements Test; Tower of Hanoi). Questionnaires on daily life inattentive behaviour were also administered to all participants and their significant others. A MANOVA indicated that patients with persisting postconcussive complaints demonstrated a general deficit in attentional performance as compared with their normal controls, F (18, 145) = 7.939, p = .005. These patterns still persisted when measures of emotional disturbance were controlled, F (18, 143) = 5.159, p = .005. Moreover, for sustained attention and selective attention, we were able to statistically control for speed and the differences remained. Future research should be conducted to better control the potential confound of speed for all the attentional components in order to differentiate any specific component deficits in these patients.