Part A quantifies the tremor at rest, with posture holding, and with action and intention manoeuvres, for nine parts of the body. Naturally, some body parts would not normally have tremor in all three situations. For example, voice tremor is a tremor of action only so the rating scale does not score voice tremor at rest or with posture. Since face, tongue, head, and trunk tremors are basically present at rest or with posture holding, this new scale eliminates scoring of those tremors in the action/intention category.

Severity of tremor in each of the nine body part is rated by amplitude. Whether the tremor is intermittent or always present (a phenomenonologic characteristic of resting tremor in parkinsonism) is not a factor in the severity score. The definitions for tremor severity indicate that 1 + and 2+ tremors could be either intermittent or continuous. Since larger amplitude tremors are less likely to be intermittent, the definitions for 3+ and 4+ severities do not list the choice for intermittency.

Tremor severity in part A is rated for three situations: rest, maintaining a posture, and performing an activity. Definitions for the three situations are provided for the limbs, tongue, head, and trunk. Face tremor is scored only as a resting tremor. The lips and chin are the most common sites of face tremor and are affected in parkinsonism particularly, rather than in other types of tremors. Tongue tremor at rest is scored with the tongue resting in the mouth; posture tremor is scored with the tongue maintained protruded from the mouth.

Voice tremor can be detected by listening to the patient talk, but it is sometimes difficult to differentiate by sound alone voice tremor and dystonic adductor dysphonia (also known as spastic dysphonia or spasmodic dysphonia). It is much easier to detect voice tremor and to distinguish it from dystonic dysphonia by having the patient utter a single sound such as "aaaahhhh……." or "eeeehhh……" and hold it for as long as possible. Voice tremor is rhythmic, whereas dystonic adductor dysphonia produces irregular interruptions of sound.

Tremor of the head and the trunk when the patient is sitting or standing is considered a postural tremor; rest tremor of the head or trunk is measured when the patient is lying down with the head and body supported against gravity.

Tremor of the arms and legs can be distal or proximal. Rest tremor of the limbs is assessed with the limbs in complete repose. Often this is easily accomplished when the patient is sitting, forearms and hands relaxing on the lap and feet supported by the floor. In individuals who are tense and cannot relax the muscles, one might have to assess for rest tremor of the limbs with the patient supine. Postural tremor of the arms is observed by having the patient stretch the arms in front of the body both with elbows extended and with elbows flexed. Postural tremor of the legs is observed by having the patient elevate the legs, which is sometimes easier if done one leg at a time. This can be accomplished with the patient sitting or lying. For ease and consistency in scoring, the sitting position is recommended. The hips and knees are flexed with the legs maintained in the air against gravity.

Action and intention tremor are given a single score. For the arms, the patient carries out the finger to nose manoeuvre as well as such other actions as buttoning, dialling telephone, writing, and bringing a cup to the mouth. Some of these activities are rated separately in part B and C of the rating scale, giving additional weight to this type of tremor in the total tremor score. For the legs, action/intention tremor is assessed by having the patient carry out the toe to finger manoeuvre. Since postural tremor will be superimposed on top of action/intention tremor, it is important to determine if the activity results in a greater tremor amplitude than that seen with posture holding alone. Similarly, rest tremor can be superimposed on top of posture tremor after the posture is maintained for several seconds. This resting component should not be misinterpreted as postural tremor.