Postural reactions

Postural reaction testing assesses both proprioceptive and motor systems. Postural reaction deficits may be observed with disease in any part of the central or peripheral nervous system. At least two of the tests described below should be performed in each patient. I generally perform proprioceptive placing and hopping in all patients.  Other postural reaction tests are performed in specific situations as described below. For each of these tests, an abnormal response suggests the lesion is located at the level of the limb (neuromuscular system, spinal cord intumescence) or cranially. Lesions in the forebrain and midbrain usually lead to contralateral postural reaction deficits, while lesions caudal to the midbrain will cause ipsilateral postural reaction deficits.

General proprioception / Proprioceptive positioning

Technique: With the patient in a standing position, gently turn over one paw and place the dorsum of the paw on the ground or exam table.

Normal response: The patient should quickly replace the paw into a normal standing position.

Tips:

  • Ask the owner to not pet or talk to patient while testing. This may be enough to distract the patient from righting the paw.
  • Do not overly manipulate the limb since excessive movements of the limbs stimulate receptors in joints and muscles.

NOTE

This test is frequently called “conscious proprioception” (a.k.a., CP) by many clinicians and board-certified neurologists, including myself out of habit and previous training, knowing full well that this is a misnomer. Dr. Alexander de Lahunta, arguably one of the greatest minds in veterinary neurology, argues that the term conscious proprioception should not be used since this test involves a great many central and peripheral components to be normal and does not truly test conscious recognition of the paw being turned over.

Hopping

Hopping is probably the most reliable of the postural reactions.

Technique: Stand over the patient and gently lift the patient so that only one limb remains on the ground. Push the patient laterally on the down limb. Alternate limbs and repeat as necessary to get an accurate portrayal of the patient’s ability to hop. For large and giant breed dogs that are too heavy to lift safely, I just hold up the opposite limb rather than all 3 limbs.

Normal response: As the shoulder or hips moves laterally over the paw, the patient should make a quick, smooth step laterally.

Wheelbarrrow

Technique: Lift the pelvic limbs off the ground and gently push the patient forward.

Normal response: The patient should make alternating steps with the thoracic limbs.

Extensor postural thrust

Technique: Hold the patient off the ground, lower the pelvic limbs to the ground and gently push the patient backward.
Normal response: The patient should immediately start making coordinated backward steps when the pelvic limbs touch the ground.

Hemistand / hemiwalk

This postural reaction test is performed rarely in my practice. I typically reserve hemistand / hemiwalk for large to giant breed dogs that are too heavy to lift. Use caution in patients with any degree of weakness. An assistant should be available to help catch the patient should it fall.

Technique: Stand on one side of the patient and lift the thoracic & pelvic limbs on one side (hemistand) and then gently push the patient away from you (hemiwalk).
Normal response: The patient should be able to stand on two legs and make coordinated lateral steps.

Placing reactions

Placing reactions are typically performed only in cats and small breed dogs and can be divided into tactile placing and visual placing. Personally, I find these tests unpredictable. Many normal patients will not place their limbs appropriately, so results should be interpreted in light of other neurological exam findings.

Technique: For tactile placing, pick the patient up and cover the eyes. Bring the patient to the edge of the exam table and watch for placing the limbs. Visual placing is performed in the same manner, but the eyes are not covered.
Normal response: The patient should immediately place the paws up onto the table as soon as the limb contacts the edge of the table for tactile placing or just before reaching the table for visual testing.