Motor Arm Drift Scoring (Items 5a and 5b) Flashcards

For NIHSS Motor Arm testing, the patient is sitting up. At what angle and for how many seconds must the arm be held to receive a score of 0?

Answer: 90° for 10 seconds

When the patient is seated, the arm is positioned at 90°. A score of 0 (no drift) requires the patient to hold that position for 10 seconds without any downward movement. If the patient is supine, the angle changes to 45°, but the hold time remains 10 seconds.

A patient holds their arm at 90° but it drifts downward before 10 seconds — however, it does not hit the bed or their lap. How is Motor Arm scored?

Answer: 1 — the arm drifts before 10 seconds but does not fall

A score of 1 is assigned when the arm drifts from the starting position before 10 seconds but does not fall all the way to the bed or the patient's lap. The distinction between score 1 (drift) and score 2 (falls completely) is critical.

For a patient who is supine, the Motor Arm test positions the arm at:

Answer: 45° with palm down

When the patient is supine, the arm is held at 45° rather than 90°. The palm-down position is standard. The angle is adjusted because gravity acts differently on a reclining patient.

A patient makes no attempt to raise their arm against gravity and it falls immediately when released. The Motor Arm score is:

Answer: 3 — no effort against gravity

Score 3 is assigned when the patient makes no effort against gravity — the arm falls immediately with no active resistance. Score 4 (paralysis) is reserved for complete absence of any movement whatsoever, including no twitch or contraction. Score 3 still implies some residual but non-functional effort is absent against gravity.

The NIHSS requires the examiner to score Motor Arm for both the left and right arm. If a patient has a pre-existing shoulder injury on the right that limits range of motion, how should the examiner proceed?

Answer: Score the injured arm as UN (untestable) and note the pre-existing condition

When a limb cannot be tested due to a pre-existing orthopedic or other non-stroke condition, the item is marked UN (untestable). The examiner must document the reason. This prevents a structural impairment from inflating the stroke severity score.

Why are the left arm (5a) and right arm (5b) scored as separate items on the NIHSS?

Answer: Because hemispheric strokes typically cause unilateral deficits, and recording each side independently localizes the lesion and tracks asymmetry

Stroke often produces unilateral motor deficits corresponding to damage in one hemisphere. Scoring left and right arms separately allows clinicians to detect asymmetry, lateralize the lesion, and track differential recovery over time. The scores are never averaged.