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Title: Spatial Working Memory and Sustained Attention in the Neglect Syndrome.
Author: Malhotra, Paresh Arjun.
ISNI:       0000 0001 3617 4326
Awarding Body: Imperial College London (University of London)
Current Institution: Imperial College London
Date of Award: 2007
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Spatial neglect is most prominently associated with damage to the right cerebral hemisphere, especially parietal and frontal regions. Although many studies of the neglect syndrome have tended to focus on spatial pathological mechanisms, an increasing body ofdata points to right hemisphere involvement in spatial and nonspatial domains, including spatial working memory (SWM) and sustained attention. The experiments described here critically examine the roles ofSWM, sustained attention and their interaction in the neglect syndrome. By employing a vertical variant of the traditional Corsi blocks it was possible to demonstrate impaired SWM in neglect. A deficit was also found using a second 'purer' task, which required no manual response or memory for sequence order. Impairment on this task correlated with neglect severity, providing evidence for a contributory role for impaired SWM in neglect. Sustained attention was examined by assessing the ability to maintain attention to centrally-displayed visual stimuli. Patients with neglect were impaired, although there was no worsening ofperformance over time, or vigilance decrement. A subsequent study revealed that neglect patients have worsening performance over time only when maintaining attention towards spatial targets... suggesting a previously undescribed interaction between spatial impairment and sustained attention in neglect. Damage to white matter underlying parietal cortex was associated with both impaired SWM and sustained attention, consistent with evidence suggesting involvement for right fronto-parietal networks in both these domains. As impaired SWM and sustained attention appear to contribute to neglect, modulation of one or both of these might lead to improvement. A proof-of-principle trial using guanfacine, anoradrenergic agent previously shown to affect SWM and vigilance, demonstrated that, in selected patients, noradrenergic stimulation leads to improved search. Together, these studies detail the roles of impaired SWM and sustained attention in neglect, in addition to exploring a possible role' for targeted pharmacological treatment.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available