Effects of prism adaptation and visual scanning training on perceptual and response bias in unilateral spatial neglect

ABSTRACT

In some patients with unilateral spatial neglect, symptoms reflect impaired lateralized spatial attention and representation (perceptual bias) whereas in others the inability to respond to stimuli located in contralesional space (response bias). Here, we investigated whether prismatic adaptation (PA) and visual scanning training (VST) differentially affect perceptual and response bias and whether rehabilitation outcome depends on the type of bias underlying symptoms. Two groups of neglect patients in the subacute phase were evaluated before, immediately after, and two weeks following 10 days of PA (n = 9) or VST (n = 9). Standard neuropsychological tests (i.e., Behavioural Inattentional Test, Diller cancellation test, and Line Bisection test) were administered to assess neglect symptoms, while the Landmark task was used to disentangle perceptual and response biases. Performance on the Landmark task revealed that PA was more effective in improving the perceptual bias, while VST mainly modulated the response bias. Neuropsychological tests performance suggested that VST is better suited to modulate neglect in patients with response bias, while PA may be effective in patients with both types of bias. These findings may offer novel insights into the efficacy of PA and VST in the rehabilitation of perceptual and response biases in patients with neglect.

KEYWORDS:

• stroke
• attention
• neuropsychological test
• rehabilitation
• perceptual motor performance

Acknowledgements

The authors would like to thank all participants who participated in this study. Our special thanks go to Silvia Moroso, Veronica Arzenton, Elodie Sibilli, Sara Ferracini for their support during the data collection.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Ministero dell’Istruzione, dell’Università e della Ricerca (grant number RICR_RILO_17_01, RICR_RILO_18_02).