Should We Bother to Look for the Babinski Sign?

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Should We Bother to Look for the Babinski Sign?

Researchers put the sign to the evidence-based test — but do the results apply to clinical practice?

Aiming to scientifically evaluate testing for the Babinski response as part of the complete neurologic examination, 10 physicians examined 10 subjects with known pyramidal findings affecting one leg (8 patients), both legs (1 patient), or neither leg (1 patient).

The authors analyzed the Babinski-response test for inter-rater reliability and then compared its accuracy to that of foot-tapping rate testing. Inter-rater reliability for the Babinski test was lower than with foot tapping ( ${kappa}$ =0.30 vs. 0.73), as was its accuracy in detecting known weakness (56% vs. 85% for foot tapping). The authors concluded that the Babinski sign "was a poor predictor of the presence of upper motor neuron weakness" and that "given the many pressures on physicians to shorten evaluation times . . . the Babinski sign should be deemphasized."

Comment: The neurologic examination has evolved with changes in the frequency of diseases. For example, much of the original "Queen Square" mental status examination was designed to be sensitive to general paralysis of the insane, but it is now directed to Alzheimer disease. These authors make the case for skipping the Babinski-response test and thereby reveal a profound misunderstanding of the unitary, contextual nature of the bedside evaluation. It is not a discontinuous process. I have little doubt that you could apply the same approach to almost every part of the examination and show it is unnecessary in the same way. If a critical amount of a work of art is removed, the impact of the painting is suddenly completely lost. The Babinski reflex itself is a continuous phenomenon, for it can be "majestic" in spinal cord disease, the only sign of a pyramidal lesion; "suspicious" in nonmotor cortical disease, retreating to the most lateral border of the foot when the frontal tonic foot grasp encroaches upon the shared cutaneous reflexogenic zone; or even faked by the malingerer. The expert examiner constantly sculpts a complete (infinite) examination into one tailored to understand the patient’s specific problem. Will there be experts in the future if the examination is taught with the Babinski sign deemphasized? Is this a way to improve the understanding of our patients’ conditions, or does it really just save healthcare dollars? If the neurologic exam comes to be performed as a mindless checklist, it will deteriorate into a vestigial ritual of little value, and laboratory testing will be the final arbiter of clinical decision making.

— Thomas D. Sabin, MD

Dr. Sabin is a member of the Journal Watch Neurology advisory board.

Published in Journal Watch Neurology January 26, 2006