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

ObjectivesTo study the factors and possible mechanisms associated with decreased self-awareness of levodopa-induced dyskinesias (LIDs) in patients with Parkinson's disease (PD).MethodsWe 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.ResultsSeven 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.ConclusionsPoor 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.     

6‐n‐propylthiouracil taste disruption and TAS2R38 nontasting form in Parkinson's disease

Background: The few studies that evaluated taste function in Parkinson's disease (PD) showed inconsistent results. The inherited ability to taste the bitter compound of 6‐n‐propylthiouracil has been considered to be a paradigm of general taste perception. 6‐n‐propylthiouracil taste perception is mediated by the TAS2R38 receptor, and reduced 6‐n‐propylthiouracil sensitivity has been associated with several diseases not typically related to taste function. Objectives: We evaluated the 6‐n‐propylthiouracil taste perception and the TAS2R38 gene as genetic risk factors for the development of idiopathic PD in PD patients and healthy controls (HC). Methods: The 6‐n‐propylthiouracil taste perception was assessed by testing the responsiveness, and the ability to recognize, 6‐n‐propylthiouracil and sodium chloride. The participants were classified for 6‐n‐propylthiouracil taster status and genotyped for the TAS2R38 gene. Results: A significant increase in the frequency of participants classified as 6‐n‐propylthiouracil nontasters and a reduced ability to recognize bitter taste quality of 6‐n‐propylthiouracil were found in PD patients when compared with healthy controls. The results also showed that only 5% of PD patients had the homozygous genotype for the dominant tasting variant of TAS2R38, whereas most of them carried the recessive nontaster form and a high number had a rare variant. Conclusions: Our results show that 6‐n‐propylthiouracil taster status and TAS2R38 locus are associated with PD. The 6‐n‐propylthiouracil test may therefore represent a novel, simple way to identify increased vulnerability to PD. Moreover, the presence of the nontasting form of TAS2R38 in PD may further substantiate that disease‐associated taste disruption may represent a risk factor associated with the disease. © 2018 International Parkinson and Movement Disorder Society     

Cardiovascular autonomic neuropathy and falls in Parkinson disease: a prospective cohort study

Journal of Neurology - Falls represent one of the main complications of Parkinson’s disease (PD), significantly lowering quality of life. Cardiovascular autonomic neuropathy (cAN) is one of...