Laterality In Parkinson’s Disease: A Neuropsychological Review

Laterality of motor symptom onset in Parkinson’s disease is both well-known and underappreciated. Treatment of disorders that have asymmetric pathological features, such as stroke and epilepsy, demonstrate the importance of incorporating hemispheric lateralization andspecialization into therapy and care planning. These practices could theoretically extend toParkinson’s disease, providing increased diagnostic accuracy and improved treatment outcomes; however, laterality in Parkinson’s disease has been largely ignored both clinically and in research. Additionally, while motor symptoms have generally received the majority of attention, non-motor features (e.g., autonomic dysfunction) also decrease quality of life and are influenced by asymmetrical neurodegeneration. Due to the laterality of cognitive and behavioral processes in the two brain hemispheres, analysis of hemibody side of onset can potentially give insight into expected symptom profile of the patient and allow for increased predictive accuracy of disease progression and outcome, thus opening the door to personalized and improved therapy in treating Parkinson’s disease patients. This review discusses motor and non-motor symptoms (namely autonomic, sensory, visuospatial, language, and emotional dysfunction) of Parkinson’s disease in respect to hemispheric lateralization from a theoretical perspective in hopes of providing a framework for future research and personalized treatment.