Potential features to select study populations at high risk for phenoconversion, for disease-modifying clinical trials in RBD
| Age | Equal or older than 65 years; or consider range between 55 and 75 years old36 37 |
| RBD features | Longer disease duration38 iRBD (ie, not due to narcolepsy, not due to brainstem lesion, not due to other known brain pathology) RBD not occurring in temporal association with antidepressant medications |
| Olfaction | Dysfunction measured by the cross-cultural 12-item test37 39 40 |
| Cognitive | Abnormal performance assessed by neuropsychological testing41 42 |
| Motor | Subtle motor dysfunction: parkinsonism, ataxia and/or dysmetria measured by the part III of the Unified Parkinson’s Disease Rating Scale37 43 44
Abnormal motor performance assessed by objective testing (eg, Purdue Pegboard) |
| Colour vision | Abnormal colour vision assessed by FM-100 |
| Autonomic | Autonomic dysfunction: constipation, urinary symptoms, erectile dysfunction, orthostatic hypotension36 45 46 |
| Dopamine imaging | DaT SPECT: reduced nigrostriatal dopaminergic binding in the putamen and striatum47 48 |
| Genetic | GBA mutation49 or other genotype that increases phenoconversion risk |
| Other | See section of Outcome Measures for Symptomatic Trials below or symptomatic trials section for discussion of imaging, biofluid and other potential selection biomarkers in development |
DaT, Dopamine transporter SPECT; FM-100, the Farnsworth Munsell 100 HueColor Vision Test; GBA, glucocerebrosidase ; iRBD, isolated rapid eye movement sleep behavioural disorder; RBD, rapid eye movement sleep behavioural disorder; SPECT, single-photon emission CT.