Adverse effect of dopamine agonist therapy in a patient with motor-intentional neglect

Studies in animals and humans report dopamine agonists can improve neglect. Because dopamine deficit reduces intention to act, it has been suspected t he dopamine agonist bromocriptine would improve deficient hemispatial inten tion. Thus, the effect of bromocriptine on line bisection was examined in a patient with neglect and failure of the action-intention system. The 58-ye ar-old patient had left-sided neglect from a right cerebral infarction invo lving both cortical and subcortical (striatal) structures. It was determine d that neglect on a line bisection task was attributable to a motor-intenti onal bias by testing under congruous and incongruous video monitoring. Test ing sessions were held before starting bromocriptine, on 20mg/d, and after stopping bromocriptine. The patient's ipsilesional bias increased on bromoc riptine, and improved when bromocriptine was stopped. Bromocriptine may wor sen neglect if putamenal receptors are damaged. Dopamine agonists may activ ate the normal hemisphere, increasing an intentional bias. Clinicians using dopaminergic pharmacotherapy should assess patients for this possible adve rse effect. (C) 1999 by the American Congress of Rehabilitation Medicine an d the American Academy of Physical Medicine and Rehabilitation.