Poor self-awareness of levodopa-induced dyskinesias in Parkinson's disease: Clinical features and mechanisms

Objectives: To study the factors and possible mechanisms associated with decreased self-awareness of levodopa-induced dyskinesias (LIDs) in patients with Parkinson's disease (PD). Methods: We enrolled 30 PD patients with LIDs. Patients were video-recorded in an "on" phase while experiencing LIDs. LIDs were objectively rated by means of the Unified Dyskinesias Rating Scale (UDyRS) by two movement disorders specialists while examining the patients. Patients were asked to rate the body site and the severity of their LIDs according to the 5-point UDyRS. Patients then rated their own LIDs while watching the video recording of themselves. Lastly, the patients rated the LIDs of other reference PD patients on a video recording. The same reference video recordings were shown to 15 healthy individuals matched for age, gender and education. Results: Seven of the 30 PD patients investigated were subjectively unaware of the presence of their LIDs. The majority of patients, however, recognized their LIDs when watching video recording of themselves. Patients displayed a specific poor self-awareness of trunk LIDs, in both the subjective evaluation and in the video recording-based subjective evaluation. By contrast PD patients correctly recognized LIDs in video recordings of reference PD patients. Poor self-awareness correlated with predominance of motor symptoms on the left body side. Conclusions: Poor self-awareness of LIDs is present in a proportion of PD patients as a form of anosognosia. The poor self-awareness of LIDs in the trunk is likely to be due to a complex interplay involving both anosognosic mechanisms and deficits in proprioceptive axial kinesthesia. (C) 2013 Published by Elsevier Ltd.