Rehabilitation of unilateral spatial neglect and neuroimaging.

We review the literature on current knowledge of the role of unilateral spatial neglect as an independent predictor of poor functional outcome after right brain injury, the neural mechanisms and neural substrates that are responsible for the manifestation of neglect behaviors, and the available rehabilitation techniques for neglect amelioration. We focus on the neuroimaging correlates of these rehabilitation techniques and rehabilitation amelioration, their mode of action and their potential to make a difference in functional outcomes, by assessing their potential to improve patients' performance in activities of daily living. We recognize that there is no consensus on efficacious treatments for neglect rehabilitation, and acknowledge that the lack of complete clarity of the neural substrates and mechanisms underlying neglect phenomena may hinder the development of efficacious rehabilitation techniques. We discuss current opinions on the neural mechanisms of hemispatial neglect and delved into the neural substrates of neglect based on functional and structural imaging. We explore the role of damage or dysfunction within specific right hemisphere structures in generating certain neglect subtypes and discussed how such knowledge may guide treatments for the rehabilitation of unilateral neglect. From this foundation, we proceed to explore the available rehabilitation techniques for neglect amelioration and how neuroimaging may guide the choice of therapies for different forms of unilateral neglect. We discuss cognitive rehabilitation approaches which form the bedrock of most traditional rehabilitation programs and follow with a description of other available, but less well utilized methods of neglect rehabilitation, including sensory stimulation, sensorimotor adaptation to visual perturbations by prism adaptation, and pharmacological agents (mainly dopamine agonists) that might augment rehabilitation. We also discuss the efficacy of these techniques in neglect rehabilitation and compare the potential of these diverse techniques to ameliorate not only the different symptoms of neglect, but also the different subtypes of neglect. Finally, we make suggestions about future research that could enhance the rehabilitation of neglect.