Abstract
Visuospatial neglect is a heterogenous syndrome which can occur following damage to either right or left hemisphere areas. This study employs voxel-lesion symptom mapping to identify the neural correlates of left and right egocentric and allocentric neglect in a large acute stroke cohort.A cohort of 446 acute stroke survivors (age = 26–95, 44% female) completed neuropsychological neglect assessment and routine clinical imaging. Similar to previous investigations, left egocentric and left allocentric neglect were associated with damage to distinct clusters of voxels within the posterior parietal and temporo-parietal junction areas. Unlike previous investigations, right egocentric neglect was found to most strongly associated with damage to more posterior voxels within left occipital cortical areas. Right allocentric neglect was found to be most strongly associated with damage to the anterior limb of the left internal capsule. Interestingly, the right hemisphere homologues of the areas implicated in right-lateralised neglect were not overlapping with those associated with left neglect impairment. This dissociation was present across both egocentric and allocentric neglect impairment.The results of this investigation suggest that right egocentric/allocentric neglect should not be characterised as a consequence of damage to left-hemisphere homologues of the right hemisphere attentional systems. These findings support the characterisation of visuospatial neglect as a heterogenous cluster of impairments rather than a unitary syndrome and provide novel insight into the neural correlates of spatial attention.
Highlights
Visuospatial neglect is most commonly characterised as a left-lateralised spatial attentional deficit which occurs following damage to right hemisphere temporo-parietal areas (Chechlacz et al, 2012; Parton et al, 2004)
While there was some degree of overlap (6.45%) between the neural correlates associated with left egocentric and left allocentric neglect, the voxels associated with right egocentric and right allocentric neglect demonstrated less than 0.5% overlap
4.2 Conclusion: The findings of this investigation elucidate the distinct neural correlates of right and left visuospatial neglect deficits in a large, representative sample of stroke survivors
Summary
Visuospatial neglect is most commonly characterised as a left-lateralised spatial attentional deficit which occurs following damage to right hemisphere temporo-parietal areas (Chechlacz et al, 2012; Parton et al, 2004). Visuospatial neglect has been found in a number of patients with damage confined to the cerebellum (Hildebrandt, Spang, & Ebke, 2002; Kim et al, 2008; Silveri, 2001) This heterogeneity in results has led to the hypothesis that visuospatial neglect represents a Journal Pre-proof disconnection syndrome (Bartolomeo et al, 2007) and this claim has been supported by studies linking left visuospatial neglect to damage to the right superior longitudinal (He et al, 2007; Thiebaut de Schotten et al, 2008), inferior longitudinal (Bird, 2006), and inferior fronto-occipital fasciculi (Urbanski et al, 2008). Treating visuospatial neglect as a heterogenous syndrome rather than a unitary behavioural deficit may help disentangle some of these findings
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