Tremor score is a domain of the global parkinsonian summary score. The tremor score is determined using a modified version of the motor portion of the United Parkinson's Disease Rating Scale (mUPDRS). A trained nurse clinician scores tremor based on 7 items:

1. Right arm resting tremor
2. Left arm resting tremor
3. Right leg resting tremor
4. Left leg resting tremor
5. Chin/jaw resting tremor
6. Right hand postural tremor
7. Left hand postural tremor

To assess resting tremor of the right and left arms and legs as well as the chin/jaw, participants are asked to sit completely relaxed and to count aloud backwards from 10. The nurse clinician observes the participant for rhythmic tremor. Participants are then instructed to hold their arms perpendicular to their body with palms down and fingers spread apart for 10 seconds. The nurse clinician observes for action and postural tremors.

Each item is scored using the respective scale below. The tremor domain score is calculated by adding the ratings for the individual items, dividing by the maximum possible score for the domain, then multiplying by 100. The domain score ranges from 0 to 100, with higher scores reflecting more tremor.

Rater responses for each item:

Items 1-5: Resting tremor

Items 6-7: Postural tremor

Note: This variable is not calculated if more than half of the items are missing.