Sleep disorder may hold key to predicting Parkinson's before symptoms start

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria (both patients and healthy controls): 1. Right-handed participants. 2. Monolingual native Italian speakers. 3. Age between 50 and 75 years old. 4. Normal or corrected-to-normal visual acuity. 5. Mini Mental State Examination (MMSE) score greater than 24. 6. Oral and written informed consent to study participation. Additional inclusion criteria for iRBD patients: 7. Diagnosis of iRBD based on International Classification of Sleep Disorders, 3rd Edition (ICSD-3) criteria: presence of REM sleep without atonia; presence of sleep-related injurious-disruptive behaviors by history or abnormal sleep behaviors documented during PSG monitoring; absence of EEG epileptiform activity during REM sleep; presence of sleep disturbance not better explained by another sleep disorder, medical or neurologic disorder, mental disorder, medication use, or substance use disorder. 8. PSG-confirmed iRBD duration since diagnosis equal or greater than 5 years. 9. Absence of clinically defined Parkinson's disease. Exclusion Criteria for iRBD patients: 1. Secondary forms of RBD on the basis of historical data, neurologic examination, and cerebral MRI findings. 2. History of other systemic, neurologic, or psychiatric diseases, head injury, cardiovascular events, and cerebrovascular alterations visible at MRI scan. 3. Alcohol and/or psychotropic drugs abuse. 4. Contraindications to MRI scan (cardiac pace-maker or other types of cardiac catheters, splinters or metallic shards, metallic prosthesis not compatible with the magnetic field generated by MRI, claustrophobia). Exclusion Criteria for Healthy Controls: 1. Sleep disorders on the basis of clinical evaluation. 2. History of systemic, neurologic, or psychiatric diseases, head injury, cardiovascular events, and cerebrovascular alterations visible at MRI scan. 3. Alcohol and/or psychotropic drugs abuse. 4. Contraindications to MRI scan (cardiac pace-maker or other types of cardiac catheters, splinters or metallic shards, metallic prosthesis not compatible with the magnetic field generated by MRI, claustrophobia). 5. Hypnotic or benzodiazepine medication.