Alpha-synuclein Rt-quic and Neurologic Symptoms in Persons With idiOpathic anosMiA

This study is investigating whether a specific protein linked to Parkinson's disease (alpha-synuclein) can be detected in people who have lost their sense of smell for no known reason (called idiopathic olfactory dysfunction). Loss of smell can sometimes be an early sign of Parkinson's disease years before movement problems begin. **You may be eligible if...** - You are between 55 and 75 years old - You have a slowly progressing, unexplained loss of smell (not due to allergies, nasal disease, injury, or surgery) - You have not been diagnosed with a neurodegenerative disease such as Parkinson's or dementia - You are able to give informed consent - (Healthy volunteers without smell problems are also eligible as controls) **You may NOT be eligible if...** - You already have a diagnosed neurological or psychiatric condition - Your smell loss is due to a known cause (such as chronic sinusitis, trauma, or medication) - You show obvious signs of dementia or Parkinson's disease - You have severe nasal abnormalities or active infections - You currently abuse alcohol or drugs Talk to your doctor to see if this trial is right for you.