Neuropsychological deficits of visuospatial attention: subtypes, clinical utility, and underlying mechanisms

Visuospatial neglect is a common neuropsychological syndrome characterised by consis- tently lateralised spatial attentional deficits. The purpose of this thesis is to investigate patterns of heterogeneity within visuospatial neglect, to determine this syndrome’s underlying mechanisms, and to investigate the practical utility of considering this heterogeneity within clinical settings. Chapter Two presents a critical analysis of common neglect assessment methods and in- vestigates the utility of neglect severity metrics which can be extracted from neuropsychological measures. Chapter Three analyses behavioural heterogeneity in neglect dyslexia to investigate the relationship between reading-related and domain-general neglect impairments. Chapter Four presents three case studies characterising representation-level neglect dyslexia in order to evalu- ate existing models of spatial attention. Chapter Five presents a detailed, lesion-mapping analysis of visuospatial neglect deficits aiming to determine whether right neglect is anatomically homolo- gous to left-lateralised neglect. Finally, Chapter Six analyses the relationship between the occur- rence of acute neglect and poor long term recovery outcomes to determine whether the specific behavioural phenotype of acute neglect impairment acts as a useful prognostic indicator. The findings of these data chapters are then cumulatively discussed to extend fundamental understanding of the neglect syndrome, establish a novel conceptualisation of representation- level neglect dyslexia, evaluate current neglect-related clinical practices, and clarify the recovery outcome of stroke survivors exhibiting acute neglect impairment.