Deficits of contralesional awareness: a case study on what paper-and-pencil tests neglect

Attentional orienting and awareness for contralesional hemispace were studied longitudinally in a woman (GB) who suffered a right hemispheric stroke without any motor impairment and who presented normal performance on standard paper-and-pencil tests for neglect but manifested difficulties in everyday life. We aimed to test whether computer-based, dual-task paradigms were sufficiently sensitive to detect the presence of subclinical neglect in GB.

We assessed the spatial awareness of GB by means of cued-detection tasks, paper-and-pencil tests, attentionally demanding dual tasks, and in several ecological settings after her discharge from the hospital. A group of right brain-damaged patients and an age-matched healthy participant were also tested with the dual tasks.

Dramatic awareness deficits for the left contralesional hemispace emerged in GB only under dual-task conditions, both in computer-based and in ecological settings, as if her degree of contralesional space awareness impairment was closely dependent on the quantity of available attentional resources. Our dual-task paradigm was also effective in quantifying awareness improvements over time. The absence of motor impairments, uncommon for a postacute patient with severe albeit hidden neglect, allowed us to ascribe her everyday life impairments for contralesional hemispace to awareness deficits. The performance of the group of patients confirmed the detrimental effects of the dual tasks, whereas the performance of the healthy control we tested was not affected by dual-task manipulation.

Our results confirm the well-known lack of sensitivity of standard neuropsychological tests to detect subclinical forms of neglect, which, nonetheless, may result in negative consequences in everyday life. Computer-based, resource-demanding paradigms seem to be a promising solution to uncover subtle awareness deficits that can affect the everyday life of stroke patients.