Spatial neglect treatment: The brain’s spatial-motor Aiming systems

ABSTRACT

Animal and human literature supports spatial-motor “Aiming” bias, a frontal-subcortical syndrome, as a core deficit in spatial neglect. However, spatial neglect treatment studies rarely assess Aiming errors. Two knowledge gaps result: spatial neglect rehabilitation studies fail to capture the impact on motor-exploratory aspects of functional disability. Also, across spatial neglect treatment studies, discrepant treatment effects may also result from sampling different proportions of patients with Aiming bias. We review behavioural evidence for Aiming spatial neglect, and demonstrate the importance of measuring and targeting Aiming bias for treatment, by reviewing literature on Aiming spatial neglect and prism adaptation treatment, and presenting new preliminary data on bromocriptine treatment. Finally, we review neuroanatomical and network disruption that may give rise to Aiming spatial neglect. Because Aiming spatial neglect predicts prism adaptation treatment response, assessment may broaden the ability of rehabilitation research to capture functionally-relevant disability. Frontal brain lesions predict both the presence of Aiming spatial neglect, and a robust response to some spatial neglect interventions. Research is needed that co-stratifies spatial neglect patients by lesion location and Aiming spatial neglect, to personalize spatial neglect rehabilitation and perhaps even open a path to spatial retraining as a means of promoting better mobility after stroke.

KEYWORDS:

• Spatial neglect
• motor-intention
• frontal lobe syndrome

Acknowledgements

The data used in this study are the property of the Kessler Foundation and the federal government. We thank Priyanka Shah-Basak for assisting with data analysis in the analysis of bromocriptine therapeutic response data. We also thank Lorie Gage Richards, whose comments and feedback about the concept of Aiming spatial neglect were very helpful to the presentation of this paper. Three reviewers read and commented on this manuscript in preliminary form, and we thank them for their useful suggestions to make our paper better.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Kessler Foundation; National Institutes of Health [grant number K24HD062647, R01NS055808]; Administration for Community Living/NIDILRR [grant number 90IF0037]; Wallerstein Foundation for Geriatric Improvement; and the Department of Veteran Affairs, Rehabilitation Research and Development Service.