What Is Old Age? Differences in Views of Old Age Between Employees and the Self-Employed.

Isolated REM sleep behavior disorder (iRBD) is a parasomnia characterized by a loss of muscle atonia during REM sleep and dream enactment, with an estimated prevalence ranging from 0.5% to 2.01% in the general population. Polysomnography (PSG) is currently the gold standard for identifying iRBD. Individuals with iRBD have a high risk of developing α-synucleinopathies, particularly Parkinson's disease (PD) and dementia with Lewy bodies (DLB). The estimated risk of phenoconversion is 33.5% after 5 years, 82.4% after 10 years, and 96.6% after 14 years. For this reason, iRBD represents an important target for potential neuroprotective therapies, and an important model for understanding disease progression of prodromal PD. Therefore, it is of paramount importance to establish biomarkers that can reliably identify and monitor subjects at high risk of rapid phenoconversion to PD. Imaging studies have demonstrated decreased striatal dopamine transporter uptake and substantia nigra hyperechogenicity as potential markers to identify individuals with iRBD at risk of phenoconversion within three years. However, these imaging methods are relatively expensive and time-consuming, and may not be readily available in all healthcare settings. Subtle motor deficits have been reported to be present in iRBD, and therefore, may be helpful markers for predicting future phenoconversion. Therefore, motor assessment methods may be relatively inexpensive tools that can aid in screening for iRBD and monitoring disease progression, particularly risk of phenoconversion. Several studies have aimed to characterize the motor impairment seen in iRBD using various motor assessment methods, however, to our knowledge, no review has aimed to summarize the existing evidence.