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At least 19 recordsLinked to original sources

PubMed1998

Auditory attentional shifts in reading-disabled students: quantification of attentional effectiveness by the Attentional Shift Index.

A controversy has existed for some years regarding auditory attentional skills in reading-disabled children. Data have suggested highly developed attentional skills in groups of reading-disabled students, but reduced attentional shifts have also been documented in equivalent groups. Attentional shifts in dichotic listening with forced or directed attention are usually inferred from a significant interaction between attentional task and ear. However, this procedure cannot be used to evaluate individual test performance, and the interaction does not give a useful measure of attentional shifts in dichotic listening meaningful for comparison with other tests of attention. In this paper attentional shifts in dichotic listening are quantified with the Attentional Shift Index (ASI), a measure for evaluating the degree of attentional shift in individual subjects. The ASI is based on the log-odds ratio of hits and intrusion errors when the subject has been tested under conditions of directed or forced attention. When 58.3% of the normative sample showed significant attentional shifts, none of the reading-disabled sample did so. This finding is discussed in relation to different types of deficits that can account for for the lack of auditory attentional shifts.

Acoustic Stimulation↗

PubMed2003

Dissociation between top-down attentional control and the time course of visual attention as measured by attentional dwell time in patients with mild cognitive impairment.

Studies of the time course of visual attention have identified a temporary functional blindness to the second of sequentially presented stimuli in that the attentional cost of attending to one visual stimulus may lead to impairments in identifying a second stimulus presented within 500 ms of the first. This phenomenon is known as the attentional blink or attentional dwell time. The neural correlates of the attentional blink and its relationship to mechanisms that control attention are unknown. To examine this relationship we tested healthy controls and subjects in the preclinical stage of Alzheimer's disease, known as mild cognitive impairment (MCI), on a paradigm which affords quantification of both the attentional blink and the top-down control of attention. When subjects were asked to identify both a number and a letter that were rapidly and sequentially presented on a visual display, the detrimental effect that identifying the first stimulus had on the ability to identify the second served as a measure of the attentional blink. When asked to identify only one of the two stimuli, the ability to ignore the first stimulus was a function of their top-down attentional control. The MCI subjects demonstrated a normal attentional dwell time but in contrast they showed impaired top-down attentional control within the same paradigm. This dissociation suggests that these two aspects of visual attention are subserved by different neural systems. The possible neural correlates of these two attentional functions are discussed.

Aged↗

PubMed2004

Early social attention impairments in autism: social orienting, joint attention, and attention to distress.

This study investigated social attention impairments in autism (social orienting, joint attention, and attention to another's distress) and their relations to language ability. Three- to four-year-old children with autism spectrum disorder (ASD; n = 72), 3- to 4-year-old developmentally delayed children (n = 34), and 12- to 46-month-old typically developing children (n = 39), matched on mental age, were compared on measures of social orienting, joint attention, and attention to another's distress. Children with autism performed significantly worse than the comparison groups in all of these domains. Combined impairments in joint attention and social orienting were found to best distinguish young children with ASD from those without ASD. Structural equation modeling indicated that joint attention was the best predictor of concurrent language ability. Social orienting and attention to distress were indirectly related to language through their relations with joint attention. These results help to clarify the nature of social attention impairments in autism, offer clues to developmental mechanisms, and suggest targets for early intervention.

Attention↗

PubMed2005

Deficient attention is hard to find: applying the perceptual load model of selective attention to attention deficit hyperactivity disorder subtypes.

BACKGROUND: Whether selective attention is a primary deficit in childhood Attention Deficit Hyperactivity Disorder (ADHD) remains in active debate. METHODS: We used the perceptual load paradigm to examine both early and late selective attention in children with the Primarily Inattentive (ADHD-I) and Combined subtypes (ADHD-C) of ADHD. RESULTS: No evidence emerged for selective attention deficits in either of the subtypes, but sluggish cognitive tempo was associated with abnormal early selection. CONCLUSIONS: At least some, and possibly most, children with DSM-IV ADHD have normal selective attention. Results support the move away from theories of attention dysfunction as primary in ADHD-C. In ADHD-I, this was one of the first formal tests of posterior attention network dysfunction, and results did not support that theory. However, ADHD children with sluggish cognitive tempo (SCT) warrant more study for possible early selective attention deficits.

Attention↗

PubMed2003

Shifts of attention in light and in darkness: an ERP study of supramodal attentional control and crossmodal links in spatial attention.

Crossmodal links in spatial attention, uncovered by recent behavioural and electrophysiological studies, have been interpreted as evidence for supramodal processes controlling shifts of attention. However, previous experiments have usually been conducted in illuminated environments. Continuously available visuo-spatial information might result in shifts of attention being primarily guided by visible information, even when another modality is task-relevant. The present ERP study evaluated this. A symbolic auditory cue directed attention to the left or right hand. Participants had to detect infrequent tactile targets delivered to the cued hand, while ignoring any visual stimuli. Stimuli were presented either in a lit environment or in darkness. Although continuous ambient visuo-spatial information was eliminated in the latter condition, processing of task-irrelevant visual events was still modulated by spatial attention for the tactile task. Moreover, ERP correlates of attentional shifts in the cue-target interval were similar for both illumination conditions. This was further confirmed in a follow-up experiment where the darkness condition was repeated without any peripheral visual stimulation ever occurring. These findings demonstrate that the ERP correlates of crossmodal attention (both preparatory effects in the cue-target interval, and also modulations of stimulus-evoked components) do not depend on selection being guided by ambient visible information in a lit environment. They suggest instead that spatial shifts of attention are controlled supramodally.

Acoustic Stimulation↗

PubMed2005

Dissecting the attention deficit hyperactivity disorder (ADHD) phenotype: sustained attention, response variability and spatial attentional asymmetries in relation to dopamine transporter (DAT1) genotype.

ADHD is a childhood-onset behavioural disorder with a heterogeneous profile of neuropsychological impairment. Neuropsychological heterogeneity may, in part, reflect underlying genetic differences. Here we examined sustained attention, response variability and spatial attentional asymmetries in a sample of children and adolescents with ADHD (n=22) in relation to dopamine transporter genotype (DAT1) and also controls (n=20). Participants performed the sustained attention to response task (SART) (testing sustained attention and response variability) and the greyscales task (a perceptual measure of attentional bias). The latter has previously been shown to yield a robust leftward attentional asymmetry in healthy subjects. The 10-repeat allele of the DAT1 gene has been associated with ADHD in a number of studies and appears to have biological significance. The ADHD group was sub-divided into those individuals with two copies of the "high-risk" 10-repeat allele (high-risk DAT1) versus those with one or no copies of this allele (low-risk DAT1). The high-risk DAT1 ADHD group displayed greater response variability on the SART than either the low-risk DAT1 group or healthy controls, whereas the latter two groups did not differ. Further, the high-risk DAT1 group showed an attenuated spatial asymmetry, relative to the low-risk DAT1 ADHD group, who showed the typical leftward attentional asymmetry. Our results suggest that the 10-repeat DAT1 allele may mediate neuropsychological impairment in ADHD. The application of molecular genetics may help to define neuropsychological impaired subgroups of ADHD.

Adolescent↗

PubMed1997

Attentional selection and attentional gradients: an alternative method for studying transient visual-spatial attention.

In two experiments, I employed an alternative method for studying transient visual-spatial attention. Instead of using precues, attention was manipulated by presenting most stimuli sequentially at predictable locations. In Experiment 1, most stimuli appeared in a regular clockwise or counterclockwise order, but some were separated by one or both visual meridians from the expected location. In Experiment 2, most stimuli were presented successively along the horizontal meridian, and some stimuli were separated by one, two, or three positions from the expected location. Faster response times and larger posterior P1 and N1 components as well as enhanced negativities at midline electrodes were found for expected-location than for unexpected-location stimuli. These effects were partially modulated by the distance of unexpected stimuli from the current focus of attention, suggesting the existence of attentional gradients. Moreover, the data suggest that the direction of previous attentional shifts and the visual meridians play an important role for spatial attention.

Adult↗

PubMed1993

Quality of attention in chronic fatigue syndrome: subjective reports of everyday attention and cognitive difficulty, and performance on tasks of focused attention.

Patients with chronic fatigue syndrome (also known as post-viral fatigue syndrome or myalgic encephalomyelitis) commonly report cognitive difficulties concerning attention, concentration and memory. In this study, patients were compared with matched controls on two questionnaires which assess subjective difficulties with attention and general cognitive functioning, and on two tasks requiring focused attention. Patients reported significantly greater difficulty with attention on the Everyday Attention Questionnaire and more cognitive symptoms on the Profile of Fatigue-Related Symptoms. The objective tests did not clearly indicate a deficit in patients' focused attention; patients tended to perform less well on the Embedded Figures Test and the Stroop Colour-Word Interference Test, but these differences were not significant. There was, however, evidence of psychomotor retardation, with patients having longer response times for word reading and colour naming in the Stroop test. Difficulties in interpreting findings for both subjective and objective cognitive measures are discussed.

Adult↗

PubMed2005

Adults with dyslexia demonstrate space-based and object-based covert attention deficits: shifting attention to the periphery and shifting attention between objects in the left visual field.

Performance on a covert visual attention task is compared between a group of adults with developmental dyslexia (specifically phonological difficulties) and a group of age and IQ matched controls. The group with dyslexia were generally slower to detect validly-cued targets. Costs of shifting attention toward the periphery when the target was invalidly cued were significantly higher for the group with dyslexia, while costs associated with shifts toward the fovea tended to be lower. Higher costs were also shown by the group with dyslexia for up-down shifts of attention in the periphery. A visual field processing difference was found, in that the group with dyslexia showed higher costs associated with shifting attention between objects in they LVF. These findings indicate that these adults with dyslexia have difficulty in both the space-based and the object-based components of covert visual attention, and more specifically to stimuli located in the periphery.

Adult↗

PubMed2000

Evidence for distinct attentional bottlenecks in attention switching and attentional blink tasks.

E. Weichselgartner and G. A. Sperling (1987), using rapid serial visual presentation (RSVP), estimated that attention could be moved to a new spatial location within 300-400 ms. H. J. Müller and P. M. Rabbit (1989) used a spatial cuing task and found a similar time course for voluntarily redeploying attention. A separate phenomenon known as the attentional blink (AB) also follows a similar time course, yet occurs when participants attend to a single spatial location. The present study found that attention can be shifted more quickly than previously estimated and that part of the deficit observed during searches of spatially distinct RSVP streams is due to an AB. The results support some early and late selection accounts for the temporal dynamics of visual attention and suggest different bottlenecks during visual selection. The implications for visual search and visual processing are discussed.

Attention↗

PubMed2005

Visual attention in behaving cats: attention shifts and sustained attention episodes are accompanied by distinct electrocortical activities.

We analyse a particular class of fast electrocortical rhythms that occur in a limited part of the primary visual cortex (BA 18) during eye saccades in behaving cats placed in a lit environment. Their high frequency (50-132 Hz) contrasts with that of two other classes of rhythms recorded in the same cortical area, the 25-45 Hz visual rhythms (40 Hz) that we previously showed to accompany sustained focused attention, and the alpha rhythms (approximately 10 Hz), that occur in situations of rest. These "very fast visual rhythms" (VFVRs) consist of two brief successive trains, a first one of low amplitude preceding the saccade onset, and a second one, much larger, during the saccade itself. The possibility is considered, that the first train subtends a presaccadic attention shift, and the second, a change of gaze towards a new target through the interception saccade. ECoG activities can thus well distinguish between attention shift and sustained attention.

Animals↗

PubMed2003

Attention, spatial representation, and visual neglect: simulating emergent attention and spatial memory in the selective attention for identification model (SAIM).

The selective attention for identification model (SAIM) is presented. This uses a spatial window to select visual information for recognition, binding parts to objects and generating translation-invariant recognition. The model provides a qualitative account of both normal and disordered attention. Simulations of normal attention demonstrate 2-object costs and effects of object familiarity on selection, global precedence, spatial cueing, and inhibition of return. When lesioned, SAIM demonstrated either view- or object-centered neglect or spatial extinction, depending on the type and extent of lesion. The model provides a framework to unify (a) object- and space-based theories of normal selection, (b) dissociations within the syndrome of unilateral neglect, and (c) attentional and representational accounts of neglect.

Attention↗

PubMed1985

Selective attention and the brain: a hypothesis concerning the hippocampal--ventral striatal axis, the mediation of selective attention, and the pathogenesis of attentional disorders.

The mechanisms mediating selective attention are not currently known. Dysfunctional selective attention is a common and prominent finding in a variety of medical and psychiatric conditions. A hypothesis is developed that efferents from the hippocampal formation are the final common pathway of processes which determine the noteworthiness of both exteroceptive and interoceptive stimuli, and that dysfunction of these efferents is a common pathway for a variety of anatomical, electrophysiological, and neurochemical lesions. This hypothesis suggests that clinical syndromes of disordered attention may be caused by various lesions of efferent connections from hippocampal formation to nucleus accumbens. The hypothesis further addresses the possibility that the threshold of hippocampus to various classes of stimuli may change on a diurnal and phasic basis. Experimental evidence that bears on the hypothesis is reviewed and experimental implications of the hypothesis are explored.

Attention↗

PubMed2006

Attentional blink and attentional capture: endogenous versus exogenous control over paying attention to two important events in close succession.

Identification of the second of two targets is impaired if it is presented less than about 500 msec after the first This attentional blink (AB) occurs under dual-task conditions in which observers are required to report both targets. AB magnitude has been estimated by subtracting the accuracy scores in the dual task from the corresponding scores in a single task in which observers are instructed to ignore the first target. Experiment 1 showed this procedure to be inappropriate, because the first target cannot be ignored. The remaining three experiments elaborated on this finding andrevealed separate endogenous and exogenous sources of the second-target deficit. A parallel was drawn between the AB deficit and the deficit observed in attentional capture. Both types of deficit can be explained on the basis of a hybrid input-filtering model in which endogenous and exogenous factors are subserved by different pathways.

Attention↗

PubMed2005

Attention-deficit disorder (attention-deficit/ hyperactivity disorder without hyperactivity): a neurobiologically and behaviorally distinct disorder from attention-deficit/hyperactivity disorder (with hyperactivity).

Most studies of attention-deficit/hyperactivity disorder (ADHD) have focused on the combined type and emphasized a core problem in response inhibition. It is proposed here that the core problem in the truly inattentive type of ADHD (not simply the subthreshold combined type) is in working memory. It is further proposed that laboratory measures, such as complex-span and dual-task dichotic listening tasks, can detect this. Children with the truly inattentive type of ADHD, rather than being distractible, may instead be easily bored, their problem being more in motivation (underarousal) than in inhibitory control. Much converging evidence points to a primary disturbance in the striatum (a frontal-striatal loop) in the combined type of ADHD. It is proposed here that the primary disturbance in truly inattentive-type ADHD (ADD) is in the cortex (a frontal-parietal loop). Finally, it is posited that these are not two different types of ADHD, but two different disorders with different cognitive and behavioral profiles, different patterns of comorbidities, different responses to medication, and different underlying neurobiologies.

Attention Deficit Disorder with Hyperactivity↗

PubMed2006

Effects of methylphenidate on multiple components of attention in children with attention deficit hyperactivity disorder.

RATIONALE: Methylphenidate (MPH) has been shown to be effective in the treatment of attention deficits in children with attention deficit hyperactivity disorder (ADHD). Although a variety of studies have been performed, there is little available information as to which components of attentional functioning are disturbed in ADHD. OBJECTIVES: The aim of the present study was to monitor the effect of MPH on various measures of attention in children with ADHD. METHODS: In a double-blind, placebo-controlled, crossover study, the attentional functioning of 58 children diagnosed with ADHD without psychiatric comorbidity was examined. Assessment of attention was performed on their usual MPH treatment and following withdrawal of the drug. Furthermore, the attentional performance of 58 healthy children was assessed. The test battery consisted of reaction time tasks, including measures of alertness, vigilance, divided attention, flexibility, and aspects of selective attention such as focused attention, inhibition, and integration of sensory information. RESULTS: In comparison to the test performance of healthy children, children with ADHD displayed impairments of vigilance, divided attention, flexibility, and aspects of selective attention including focused attention, inhibition, and integration of sensory information. Statistical comparison of attentional functioning of children with ADHD on and off MPH treatment revealed that the medication resulted in an improved task accuracy regarding vigilance, divided attention, inhibition, focused attention, integration of sensory information, and flexibility. CONCLUSION: The present findings indicate that various aspects of attention are markedly impaired in children with ADHD. Treatment with MPH was accompanied by improvements in attention functions of small to moderate sizes. Although MPH-induced improvements were observed in a broad range of attention measures, children with ADHD who were on MPH treatment nevertheless displayed serious deficits in a number of components of attention.

Attention↗

PubMed2005

Treating attention in mild aphasia: evaluation of attention process training-II.

UNLABELLED: This study examined whether attention processing training-II [Sohlberg, M. M., Johnson, L., Paule, L., Raskin, S. A., & Mateer, C. A. (2001). Attention Process Training-II: A program to address attentional deficits for persons with mild cognitive dysfunction (2nd ed.). Wake Forest, NC: Lash & Associates.; APT-II], when applied in the context of a multiple baseline ABA design, would improve the attention abilities of RW, a patient with mild conduction aphasia and concomitant attention and working memory deficits. We also explored whether APT-II training would enhance RW's auditory comprehension, other cognitive abilities such as memory, and his and his spouse's perceptions of his daily attention and communication difficulties. With treatment, RW improved on trained attention tasks and made modest gains on standardized tests and probes that evaluated cognitive skills related to treatment activities. Nominal change in auditory comprehension and untrained attention and memory functions was observed, and neither RW nor his spouse reported noticeable improvements in his daily attention or communication abilities. These and previous findings indicate that structured attention retraining may enhance specific attention skills, but that positive changes in broader attention and untrained functions are less likely. LEARNING OUTCOMES: As a result of reading this article, the participant will be able to: (1) summarize the previous literature regarding attention impairments and treatment approaches for patients with aphasia. (2) describe how Attention Processing Training-II affected the attention, auditory comprehension, and other cognitive abilities of the patient in this study.

Aphasia, Wernicke↗

PubMed2004

[Effects of distractors on sustained attention in children with attention-deficit hyperactive disorder].

OBJECTIVE: Using an experimental design combining the sustained attention task (CPT, SART) and the flanker task, we investigated: 1) whether children with attention-deficit hyperactive disorder (ADHD) have deficits in their sustained attention; 2) whether distractors have different effects on response to targets at different sustained attention levels; 3) whether different subtypes of ADHD children show different patterns in sustained attention. METHODS: Subjects were recruited from elementary school (Grade 2 - 6). Twenty seven ADHD children (23 male, 4 female) and 29 normal controls (24 male, 5 female) were matched by IQ and age. The cognitive experiment measuring reaction times and error rates was conducted on a computer using DMDX software. ADHD and normal children's performance in sustained attention and the effect of distractors were analyzed, and the results of subtypes of ADHD were compared. RESULTS: ADHD children and normal children did not show significant differences in error rates in their response to dominant (non-attentional) item. However, distractors impaired ADHD children's response to targets. ADHD children also showed more errors than normal children in the sustained attention task, but compared with the non-distractor condition, distractors facilitated their response. CONCLUSIONS: ADHD children have deficits in their sustained attention, reflecting the deficits in brain development. More importantly, this study found that the effects of distractors in sustained attention can be dissociated according to the level of demand on sustained attention: distractors interfered with responses to targets when the demand on sustained attention was low, and they facilitated responses to targets when the demand on sustained attention was high. There were no significant differences between ADHD-inattentive type and ADHD-combined type in their deficits in sustained attention.

Attention↗