Pathological plantar response. II. Loss of significance of stimulus site.

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Abstract
Reflex patterns were recorded in the short hallux from painful stimulation of 10 msec. to the hallux ball or to the hollow of the foot in 120 patients with lesions of the central nervous system. These patterns were contrasted in relation to varying degrees of severity and levels of injuries in the nervous system. It was shown that contrast might be preserved or abolished in patients with either patterns of dominant extensor or flexor activity. A decrease in contrast, therefore, must be related to another type of injury in the reflex mechanism other than that responsible for increased extensor activity. Contrast might be abolished in cases of cerebral hemispheric lesions and was usually absent in cases of total cord transection. In view of these data, it was presumed that contrast is dependent on cortical influence over spinal reflex centers. Total paralysis of the toes was usually accompanied by loss of contrast. Loss of sensibility on the plantar surface was accompanied by an increase of reflex threshold and a decrease of contrast. Clinically, studies of contrast would only exceptionally furnish diagnostic data not more readily obtainable by other methods.