41 resultados para Attention Visuo-Spatiale


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Over the last two decades there has been a marked change in the way that the public perceives environmental issues and the concepts associated with sustainable development. Few would argue that this has moved into the mainstream of public consciousness. Coverage of sustainability related concepts within the media, as illustrated by a sample of 112 worldwide newspapers, shows a clear upward trajectory. Taking the example of climate change and sustainable development this paper explores this increasing coverage, and arguably awareness of, sustainability concepts and considers parallels with the concepts of punctuated equilibrium and issue-attention cycles.

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OBJECTIVE:

To compare the performance of patients with mild-moderate Alzheimer's disease (AD) and vascular dementia (VaD) on tests of information processing and attention.

METHOD:

Patients with AD (n=75) and VaD (n=46) were recruited from a memory clinic along with dementia-free participants (n=28). They underwent specific tests of attention from the Cognitive Drug Research battery, and pen and paper tests including Colour Trails A and B and Stroop. All patients had a CT brain scan that was independently scored for white-matter change/ischaemia.

RESULTS:

Attention was impaired in both AD and VaD patients. VaD patients had more impaired choice reaction times and were less accurate on a vigilance test measuring sustained attention. Deficits in selective and divided attention occurred in both patient groups and showed the strongest correlations with Mini Mental State Examination scores.

CONCLUSION:

This study demonstrates problems with the attentional network in mild-moderate AD and VaD. The authors propose that attention should be tested routinely in a memory clinic setting.

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The control of social attention during early infancy was investigated in two studies. In both studies, an adult turned towards one of two targets within the infant's immediate visual field. We tested: (a) whether infants were able to follow the direction of the adult's head turn; and (b) whether following a head turn was accompanied by further gaze shifts between experimenter and target. In the first study, 1-month-olds did not demonstrate attention following at the group level. In addition, those infants who turned towards the same target remained fixed on it and did not shift attention again. In Study 2, we tested infants longitudinally at 2-4 months. At the group level, infants followed the adult's head turn at 3 and 4 months but not at 2 months. Those infants who turned towards the same target at 3 and 4 months also shifted gaze back and forth between experimenter and target. By 3 months, infants seem able to capitalize on the social environment to disengage and distribute attention more flexibly. The results support the claim that the control of social attention begins in early infancy, and are consistent with the hypothesis that following the attention of other people is dependent on the development of disengagement skills.

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We report a longitudinal study investigating developmental changes in the structure of attention engagement during early infancy. Forty-three infants were observed monthly from 2 to 4 months. Attention engagement was assessed from play interactions with parents, using a coding system developed by Bakeman and Adamson (1984). The results indicated a developmental transition in attention engagement at 3 months: after this age infants engaged for longer periods and in a wider variety of states. Most infants displayed person engagement at 2 months, passive joint engagement at 3 months, and object engagement at 4 months. To address whether emerging abilities of attention engagement allow infants to follow the attention of social partners, we compared attention engagement to performance on an experimental measure of attention control (reported by Perra & Gattis, 2010). Analyses revealed a positive relation between passive joint engagement and checking back, suggesting that changes in passive joint engagement reflect the development in attention control.

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Previous eye tracking research on the allocation of attention to social information by individuals with autism spectrum disorders is equivocal and may be in part a consequence of variation in stimuli used between studies. The current study explored attention allocation to faces, and within faces,
by individuals with Asperger syndrome using a range of static stimuli where faces were either viewed in isolation or viewed in the context of a social scene. Results showed that faces were viewed typically by the individuals with Asperger syndrome when presented in isolation, but attention to the eyes was significantly diminished in comparison to age and IQ-matched typical viewers when faces were viewed as part of social scenes. We show that when using static stimuli, there is evidence of atypicality for individuals with Asperger syndrome depending on the extent of social context. Our findings shed light on the previous explanations of gaze behaviour that have emphasised the role of movement in atypicalities of social attention in autism spectrum disorders and highlight the importance of consideration of the realistic portrayal of social information for future studies.

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Autism is a neuro-developmental disorder defined by atypical social behaviour, of which atypical social attention behaviours are among the earliest clinical markers (Volkmar et al., 1997). Eye tracking studies using still images and movie clips have provided a method for the precise quantification of atypical social attention in ASD. This is generally characterised by diminished viewing of the most socially pertinent regions (eyes), and increased viewing of less socially informative regions (body, background, objects) (Klin et al., 2002; Riby & Hancock, 2008, 2009). Ecological validity within eye tracking studies has become an increasingly important issue. As of yet, however, little is known about the precise nature of the atypicalities of social attention in ASD in real-life. Objectives: To capture and quantify gaze patterns for children with an ASD within a real life setting, compared to two Typically Developing (TD) comparison groups. Methods: Nine children with an ASD were compared to two age matched TD groups – a verbal (N=9) and a non-verbal (N=9) comparison group. A real-life scenario was created involving an experimenter posing as a magician, and consisted of 3 segments: a conversation segment; a magic trick segment; and a puppet segment. The first segment explored children’s attentional preferences during a real-life conversation; the magic trick segment explored children’s use of the eyes as a communicative cue, and the puppet segment explored attention capture. Finally, part of the puppet section explored children’s use of facial information in response to an unexpected event. Results: The most striking difference between the groups was the diminished viewing of the eyes by the ASD group in comparison to both control groups. This was found particularly during the conversation segment, but also during the magic trick segment, and during the puppet segment. When in conversation, participants with ASD were found to spend a greater proportion time looking off-screen, in comparison to TD participants. There was also a tendency for the ASD group to spend a greater proportion of time looking to the mouth of the experimenter. During the magic trick segment, despite the fact that the eyes were not predictive of a correct location, both TD comparison groups continued to use the eyes as a communicative cue, whereas the ASD group did not. In the puppet segment, all three groups spent a similar amount of time looking between the puppet and regions of the experimenter’s face. However, in response to an unexpected event, the ASD group were significantly slower to fixate back on the experimenter’s face. Conclusions: The results demonstrate the reduced salience of socially pertinent information for children with ASD in real life, and they provide support for the findings from previous eye tracking studies involving scene viewing. However, the results also highlight a pattern looking off-screen for both the TD and ASD groups. This eye movement behaviour is likely to be associated specifically with real-life interaction, as it has functional relevance (Doherty-Sneddon et al., 2002). However, the fact that it is significantly increased in the ASD group has implications for their understanding of real life social interactions.

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The majority of children who are born very preterm escape major impairment, yet more subtle cognitive and attention problems are very common in this population. Previous research has linked infant focused attention during exploratory play to later cognition in children born full-term and preterm. Infant focused attention can be indexed by sustained decreases in heart rate (HR). However there are no preterm studies that have jointly examined infant behavioral attention and concurrent HR response during exploratory play in relation to developing cognition. We recruited preterm infants free from neonatal conditions associated with major adverse outcomes, and further excluded infants with developmental delay (Bayley Mental Development Index [MDI?

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There is evidence that the developmental trajectory of cortisol secretion in preterm infants is altered, with elevated basal cortisol levels observed postnatally through at least 18 months corrected age (CA). This alteration is possibly due to neonatal pain-related stress. High cortisol levels might contribute to greater risk of impaired neurodevelopment. Since maternal factors are important for the regulation of infant stress responses, we investigated relationships between infant (neonatal pain-related stress, attention, cortisol) and maternal (stress, interactive behaviors) factors at age 8 months CA. We found that interactive maternal behaviors buffered the relationship between high neonatal pain-related stress exposure and poorer focused attention in mothers who self-reported low concurrent stress. Furthermore, in preterm infants exposed to high concurrent maternal stress and overwhelming interactive maternal behaviors, higher basal cortisol levels were associated with poor focused attention. Overall, these findings suggest that maternal factors can influence the cognitive resilience at 8 months of preterm infants exposed to early life stress.

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Purpose: This study examines long-term neuropsychological and psychosocial outcomes of survivors of malignant middle cerebral artery infarction treated via decompressive hemicraniectomy. Method: A case series design facilitated a detailed analysis of the outcomes among five participants. Neuropsychological domains assessed included premorbid and current IQ, sustained, selective and divided attention, visual and auditory memory, executive functioning and visuo-spatial ability. Psychosocial domains assessed included self-rated depression, anxiety and quality of life. Participants and their main carer were asked about their retrospective view of surgery. Results: All participants showed neuropsychological impairments in multiple cognitive domains, with preserved ability in others. Effects of laterality of brain function were evident in some domains. Clinically significant depression was evident in two participants. Overall quality of life was within average limits in three of four assessed participants. Four participants retrospectively considered surgery as having been a favourable course of action. Conclusion: While neuropsychological impairments are highly likely post-surgery, preserved abilities and social support may serve a protective function against depression and an unacceptably poor quality of life. Results do not support the suggestion that decompressive hemicraniectomy following malignant middle cerebral artery infarction necessarily leads to unacceptable neuropsychological or psychosocial outcomes.

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Objectives: To investigate the role of the prefrontal cortex in attention-based modulation of cortical somatosensory processing.

Methods: Six prefrontal stroke patients were compared with eleven neurologically intact older adults during a vibrotactile discrimination task. All subjects attended to stimuli on one digit while ignoring distracter stimuli on a separate digit of the same hand. Subjects were required to report infrequent targets on the attended digit only. Throughout testing electroencephalography was used to measure event-related potentials for both task-relevant and irrelevant stimuli.

Results: Prefrontal patients demonstrated significant changes in cortical somatosensory processing based on attention compared to age-matched controls. This was evident both in early unimodal somatosensory processing (i.e. P100) and in later cortical processing stages (i.e. long-latency positivity). Moreover, there was a tendency towards a tonic loss of inhibition over early somatosensory cortical processing (i.e. P50).

Conclusions: The attention-based modulation noted for neurologically intact older adults was absent in prefrontal lesion patients.

Significance: The present study highlights the important role of prefrontal regions in sustaining inhibition over early sensory cortical processing stages and in modifying somatosensory transmission based on task-relevance. Notably these deficits extend beyond those previously shown to occur as a function of age.