A Dissociation Between Visual and Auditory Hemi-inattention: Evidence from Temporal Order Judgements

Patients with right hemisphere brain lesions often suffer from deficits in spatial attention that can be manifested in different sensory modalities. It has recently been claimed that a relationship (i.e., association) could exist between symptoms of hemi-inattention in different modalities, based on correlations between the results of visual and auditory clinical tests of neglect or extinction. However, it should be noted that the visual and auditory tasks varied greatly both in response type and level of sensitivity. Here, we have examined cross-modal associations in spatial attention deficits using a temporal order judgment task (TOJ) in which patients were required to identify which of two visual or auditory objects had appeared first. When compared to age and education matched control participants, the patients needed, on average, the contralesional stimulus to lead the ipsilesional stimulus to achieve the point of subjective simultaneity (PSS). No association between the degree of visual and auditory hemi-inattention was observed amongst the patients, suggesting that there is a certain degree of independence between the mechanisms subserving spatial attention across sensory modalities.