How to Assess Motor Function
It’s Jenna’s first day of duty at the Intensive Care Unit. Currently, she is a fourth year nursing student and is on her 2nd month of clinical exposure. Today, they are asked to just observe the routines and procedures performed in the area since it’s their first day.
She hears the staff nurse assigned to cubicle 2 tell the staff nurse from cubicle 3 that she is about to perform motor function assessment. Curious, Jenna asks if she could observe while the nurse this. Finally, another learning she would be gaining today. She follows the staff nurse into the cubicle and observes intently on how the procedure is done.
When assessing motor function, from a neurological perspective, the assessment should focus on arm and leg movement. Considerations must include:
- muscle size
- muscle tone
- muscle strength
- involuntary movements
- posture, gait
Note: Symmetry is the most important consideration when identifying focal findings. Compare one side of the body to the other when performing your assessment.
How to assess conscious patient:
- Limb assessment of a conscious patient usually involves a grading of strength (see below)
- 5 Full ROM against gravity and resistance; normal muscle strength
- 4 Full ROM against gravity and a moderate amount of resistance; slight weakness
- 3 Full ROM against gravity only, moderate muscle weakness
- 2 Full range of motion when gravity is eliminated, severe weakness
- 1 A weak muscle contraction is palpated, but no movement is noted, very severe weakness
- 0 Complete paralysis
- Assess the patient in a supine position.
- Ask him/her to separate both legs to test for hip abduction.
- Then ask the patient to bring the legs back together to test for hip adduction.
- Sit the patient on the side of the bed to assess knee flexion and extension.
- Ask the patient to flex and extend the knee. If able to do this, apply resistance as these movements are repeated.
- Test plantar and dorsiflexion by having the patient push down against your hand with their foot and then pull up against your hand with their foot. Remember to compare left side to right side.
- Assess ability to flex elbow (biceps) and straighten (triceps).
- Assess ability to raise shoulders and return to a resting position.
- Assess wrist flexion and extension. Test each function with resistance.
- For focused upper extremity assessment, assess each digit for flexion, extension and lateral movement.
How to assess Unconscious Patient
- Observe the patient for spontaneous/involuntary movement
- Apply painful stimuli to elicit a motor response (start with central pain; move to peripheral pain if no response occurs).
- Assess for paralysis of the limb by lifting both arms and releasing them together. If one limb is paralyzed it will fall more rapidly than the non-paralyzed arm.
- Observe for spontaneous/involuntary movement
- Apply painful stimuli to elicit a motor response.
- Begin with central pain. Nailbed or peripheral pain can be attempted if the patient doesn’t respond to central pain (caution needs to be used when interpreting peripheral pain as it may stimulate spinal reflex responses vs withdrawal or other more deliberate responses).
- To assess for paralysis of the one limb you can position the patient on their back and flex the knees so that both feet are flat on the bed. Release the knees simultaneously. If the leg falls to an extended position with the hip externally rotated, paralysis is present.
- The normal leg should stay in the flexed position for a few seconds and then gradually assume its previous position.