Low Incidence Of Extensor Plantar Reflex In Newborns In An Indigenous African Population

Abstract

Background The plantar reflex has been reported to be predominantly flexor in African infants and in African subjects with lesions of the corticospinal tracts. This study was done to determine the incidence of extensor plantar reflex in healthy full-term newborns in an indigenous African population. Methods Healthy term newborns with Apgar score of 8 and above at one minute were recruited into the study consecutively in a maternity hospital in Ibadan, Nigeria. The plantar reflex was elicited by stroking the lateral side of the sole with firm pressure, between 24 - 48 hours after delivery. Results Of 461 newborns, the plantar reflex was extensor in 85, flexor in 374, and absent in two. The cumulative incidence of extensor plantar reflex was 18 % (95 % CI 15 - 22), while the standardised incidence ratio was 25 % (95 % CI 22 - 27). Conclusion This study shows that the plantar reflex is predominantly flexor in this indigenous African population. Although the physiological basis of this finding is not known, it may indicate early maturation of the corticospinal tracts in African newborns. But Le but de l\'etude est de determiner l\'incidence du reflexe cutane plantaire chez des nouveaux nes Africains en bonne sante. Methode Les nouveaux nes a terme avec un score d\'Apgar de 8 ou plus ont ete inclus dans une etude consecutive realisee dans la maternite d\'Ibadan au Nigeria. Le reflexe cutane plantaire a ete recherche selon les regles, 24 et 48h apres la delivrance. Resultats Sur 461 nouveaux nes le reflexe cutane a ete observe en extension dans 85 cas et en flexion dans 374 cas et absent dans 2 cas. L\'incidence cumulative du reflexe cutane plantaire etait de 18% (95% CI 15-12), tandis que le ratio de l\'incidence standard etait de 25% (95% CI 22-27) Conclusion Cette etude montre que le reflexe cutane plantaire est predominant en flexion dans cette population africaine autochtone. Bien que les bases physiologiques de ce constat ne soit pas connu, il pourrait indiquer la precoce maturation du tractus cortico spinal chez le nouveau ne africain Keywords : plantar reflex, Babinski, African, neonate, Afrique, nouveau-ne, examen neurologique, reflexes, reflexes cutane plantaire African Journal of Neurological Sciences Vol. 24 (1) 2005: pp. 25-28