[Clinical studies on chaddock reflex].

One hundred neurological cases were evaluated for the positive rates of 6 pathological reflexes by the same examiner (author). Chaddock and Babinski reflexes were highly sensitive, their positive occurrence being 97.1% and 80.3% of the cases respectively, compared with other pathological reflexes. In patients with paresthesia on the soles, cold feet or foot grasping, Chaddock reflex was superior to Babinski, but in some cases Chaddock became definitely positive despite negative Babinski without attributable reasons, suggestive of the former is more sensitive than the latter. The original stimulation site in Chaddock reflex is the skin area just beneath the external malleolus, and within sural nerve distribution. The elicitation of Chaddock reflex was attempted by stimulating the dorsum of the foot from medial to lateral border, with definite positive responses from the areas of sural nerve distribution. To evaluate the sensitivity and receptive field of Chaddock reflex more objectively, the electromyographic method was employed in 13 cases. The needle electrode was inserted into the extensor hallucis longus (EHL) to monitor the up-going toe, as well as flexor hallucis brevis (FHB) for the plantar flexion of the toe, and the surface electric stimulator was applied to 7 different points of the foot and leg, including original Chaddock and Babinski zones. The results of electrical stimulations to 7 different sites revealed that definitely better responses of EHL in sural nerve distribution, compared with other nerve supply. The threshold strength to evoke the action potentials in EHL proved that Chaddock's area was significantly more sensitive than Babinski's area. The relationship of latencies between EHL and FHB on electrical stimulations to the Chaddock's and Babinski's areas showed that earlier and better responses in EHL than in FHB in Chaddock, which could be another reason that Chaddock reflex was more sensitive than Babinski. From the clinical and electromyographic evaluations mentioned above, Chaddock reflex is not just a variant of Babinski reflex, more sensitive and accurate, and its receptive field is considered to be in sural nerve distribution.