The plantar reflex: additional value of stroking the lateral border of the foot to provoke an upgoing toe sign and the influence of experience

The aim of this work was to determine the value of stroking the lateral dorsal border of the foot, in addition to stroking the sole in patients with a suspected pyramidal tract lesion. In addition, we studied the differences in interpretation between neurologists, residents, and medical students. We included subjects who had weakness of at least one leg and in whom a pyramidal tract lesion was suspected. After testing muscle power, tone, reflexes, and foot tapping, a decision on the presence of a pyramidal syndrome had to be made by each observer. After stimulating the sole as well as the lateral border of the foot, observers made a decision about the presence of a pyramidal syndrome again. Twenty-two legs of 18 patients were examined. Testing the plantar reflex (according to both methods) led to a change of opinion on the presence of a pyramidal syndrome in 45 of 69 (65 %) observations. On analysis according to level of experience, a change of opinion occurred in 19 (86 %) observations by medical students, 15 (65 %) by residents, and 11 (46 %) by neurologists. On eight occasions, the change was prompted by stimulation of the lateral border; in five of these cases the examiner (three medical students and two residents) found a new pathological response. Consecutively stroking the sole and the lateral border may be of added value, especially for less-experienced physicians. It seems that more-experienced physicians need fewer tests in the physical examination in order to identify a pyramidal syndrome of the leg.