Patient case (clinical description): A 60-year-old man comes to the clinic complaining of hand tremor that started few months ago.  It is most bothering when he wants to drink from a glass or pour from a bottle. He does not smoke, but drinks occasionally. He recently started consuming more alcohol as his tremor subsides somewhat when he drinks small amounts of alcohol.  Family history is significant for similar problems in his mother.  Vital signs are normal and the patient has no other medical conditions.  Neurologic examination shows bilateral tremor in the upper extremities. The diagnosis of essential tremor is confirmed.

Patient's own account: I'm only a 60 years old man but I already suffer from shaky hands. It started a few months ago, and it really bothers me when I want to pour myself a glass or even while drinking. I don't smoke, but I drink alcohol from time to time. To be honest, I've been drinking a little more lately since it helps me with the shaking. My mom had the same issue when she was my age. The doctor took my vitals, and they were normal. I don't have any other medical issues. I underwent neurological exams and it showed that I’m shaky from both sides. The doctor diagnosed me with essential tremor.

Clinical trial: MRI Study of Brain Activity in Healthy Adults and Individuals With Parkinsonism and Rapid Eye Movement Disorder.

Eligibility criteria:
Inclusion Criteria:

          -  Healthy Control • Age 35-85

        Parkinson Disease (PD) Age 35-85

        Diagnosis of clinically definite PD made by a movement disorders specialist, with evidence
        of the following features:

          -  Presence of bradykinesia and 1 or both of the following:

               1. Rest tremor

               2. Rigidity

          -  Asymmetric Onset

          -  Progressive motor symptoms

          -  Levodopa responsive

          -  Duration at least 1 but not more than 10 years

          -  Hoehn and Yahr Stage 1-2

        Progressive Supranuclear Palsy (PSP) Age 40-85

        Diagnosis of clinically definite PSP, with the following features:

          -  Gradually progressive disorder.

          -  Onset after age 39

          -  Supranuclear palsy* and postural instability with falls in the first year of disease
             onset*.

          -  No evidence of other disease.

        Parkinsonism of Other or Undetermined Cause (POC) Age 35-85

        Diagnosis of parkinsonism of undetermined other other cause by a movement disorders
        specialist, with the following features:

          -  Signs and symptoms of Parkinsonism including

               1. Bradykinesia

               2. Mixed or resting tremor

               3. Rigidity

               4. Characteristic deficits of gait and balance associated with Parkinsonism

                  Essential Tremor (ET) Age 35-85

                  Diagnosis of essential tremor, with the following features:

          -  A 2+ postural tremor of at least 1 arm (a head tremor may also be present, but is not
             sufficient for diagnosis)

          -  On examination, there must be

               1. a 2+ kinetic tremor during at least 4 tasks, or;

               2. a 2+ kinetic tremor on 1 task and a 3+ kinetic tremor on a second task; tasks
                  include pouring water, using a spoon to drink water, drinking water,
                  finger-to-nose, and drawing a spiral

          -  If on examination, the tremor is present in the dominant hand, then by report, it must
             interfere with at least 1 activity of daily living.

        REM Behavior Disorder (RBD) Age 25 - 85

        Documented diagnosis of REM sleep behavior disorder (RBD) by a sleep medicine specialist,
        with the following clinical features:

          -  Presence of REM sleep without atonia on polysomnography

          -  At least one of the following conditions:

               1. Sleep-related, behaviors by history (eg, dream enactment behavior)

               2. Abnormal REM sleep behavior documented during PSG monitoring

        Exclusion Criteria:

        Healthy Control

          -  Pregnancy

          -  First-degree blood relative affected by PD

          -  Neurodegenerative disease

          -  History of repeated head injury, encephalitis, brain surgery, stroke, dementia,
             neuroleptic exposure, or serious medical illness that may interfere with
             participation.

        Parkinson Disease (PD)

          -  Any exclusion criteria that would exclude a healthy control patient

          -  Atypical features indicative of a Parkinson-Plus disorder

        Progressive Supranuclear Palsy (PSP)

          -  Any exclusion criteria that would exclude a healthy control patient

          -  Any finding atypical for PSP

          -  Neuroradiologic evidence of relevant structural abnormality unrelated to appropriate
             changes known to be associated with PSP

        Parkinsonism of Other or Undetermined Cause (POC)

          -  Any exclusion criteria that would exclude a healthy control patient

          -  Signs and symptoms suggestive of clear diagnosis of idiopathic Parkinson disease,
             Progressive Supranuclear Palsy, or Essential Tremor

        Essential Tremor (ET)

          -  Any exclusion criteria that would exclude a healthy control patient

          -  No other potential etiologic factors for the tremor

          -  Any first-degree blood relative affected by PD

          -  History of neurodegenerative disease

        REM Behavior Disorder (RBD)

          -  Any exclusion criteria that would exclude a healthy control patient

          -  Sleep disorder not better explained by another sleep disorder, medical or neurological
             disorder, mental disorder, medication use, or substance use disorder
No condition on gender to be admitted to the trial.
Accepts Healthy Volunteers
Subject must be at least 19 Years old.
Subject must be at most 85 Years

Eligibility (NLI label): Contradiction