Motor Grade 0 Assessment and Clinical Significance

Standardized Grading Systems

The American College of Cardiology/American Heart Association/American Association for Thoracic Surgery guidelines define a 5-point scale for lower extremity motor function assessment, where Grade 0 = No movement, Grade 1 = Flicker of movement, Grade 2 = Able to bend knee to move leg, Grade 3 = Unable to perform straight leg raise against gravity, but better leg movement, and Grade 4 = Normal movement with expected later or demonstrated ambulation 1
The Fugl-Meyer Motor Assessment uses a 3-point ordinal scale, where 0 = No active motion, 1 = Partial motion, and 2 = Motion appears to be normal, applicable to both upper and lower extremity assessments 2, 3, 4, 5

When evaluating extremities with no movement, observe for any visible muscle contraction or joint motion, and look specifically for even a "flicker of movement" which would upgrade the score to grade 1 1
Test all major muscle groups systematically, including shoulder, elbow, wrist, finger for upper extremity, and hip, knee, ankle for lower extremity 2, 3
A motor grade of 0 requires immediate physician notification in postoperative settings, as it may represent early and potentially reversible paralysis, particularly after thoracic aortic procedures where spinal cord perfusion is at risk 1

Do not confuse absence of voluntary movement with flaccidity, as grade 0 specifically refers to no active motion, regardless of tone 1, 2
Ensure the patient is attempting to move, and distinguish from sensory deficits by confirming the patient understands the command and is attempting movement 1