Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease, with over 12 million patients expected globally by 2040. The disease is currently diagnosed at the appearance of motor symptoms, but by then, over 60% of striatal dopaminergic neurons have already been destroyed. Prodromal symptoms such as idiopathic REM Sleep Behavior Disorder (iRBD), anosmia, mood disorders and constipation appear earlier and are listed as criteria for a prodromal PD diagnosis. Identifying early signs is critical to initiate neuroprotective treatments as early as possible. While pain is prevalent and highly disabling in early PD, no data are currently available on pain perception in iRBD patients, whose condition is of the main risk factor for PD development.

Inclusion criteria:

• Diagnosed with iRBD confirmed by polysomnography;
• No clinical diagnosis of Parkinson's disease or other diagnosis of neurodegenerative disease;
• Ability to understand and complete study procedures and questionnaires;

Control group:

• Diagnosed with narcolepsy type 1;
• Coexisting REM sleep behavior disorder confirmed by polysomnography;
• Ability to understand and complete study procedures and questionnaires;

Exclusion Criteria:

• Diagnosed Parkinson's Disease, dementia with Lewy bodies or multiple system atrophy;
• Severe depression according to Diagnostic and Statistical Manual of Mental Disorders (DSM V);
• Inability to complete study procedures or questionnaires.