Hemiakinesia is akinesia or hypokinesia (inability or difficulty initiating movement) confined to one side of the body. Although hemiakinesia is the norm at the onset of idiopathic Parkinson’s disease ("hemiparkinsonism"), persistent hemiakinesia should prompt a reevaluation of this diagnosis. Corticobasal degeneration often remains unilateral; a search for structural lesions of the basal ganglia should also be undertaken. Hemiakinesia may also indicate motor neglect, usually with right-sided lesions. Lesions of the basal ganglia, ventral ("motor") thalamus, limbic system, and frontal lobes may cause hemiakinesia.