Asymmetrical Tonic Neck Reflex in Children

INTRODUCTION

Approaches to treatment of central nervous system dys­function such as Bobath’s neurodevelopmental approach (Bobath and Bobath, 19 72) and Ayres’ sensori-integrative approach (Ayres, 19 72) incorporate a developmental view of central nervous system function. Such a view suggests that with maturation increasingly higher levels of integration in­corporate early responses within more adaptable and complex ones. For example, certain reflexes which are normally seen in early development have less effect with increased maturity. Such a reflex is the asymmetrical tonic neck re­flex (ATNR) . The ATNR, according to Hellebrandt, et al. (1962) , was originally described by Magnus and de Kleijn as elicited by a sideward rotation of the head. With rotation, extensor tone increases in the muscles of the “jaw-arm and -leg” (the side of the body toward which the face is turned). At the same time flexor tone increases in the “skull-arm and -leg” (the opposite side) . The commonly held clinical view of the developmental course of the ATNR is that it can be seen in normal infants between 1 week and 5 months of age. It is believed to be inhibited as the central nervous system matures (Peiper, 1963) . However, research suggests that the ATNR continues to influence movement in normal adults under certain conditions in eluding relaxation and exercise stress (Fukuda, 1959, 1961; Helle-brandt, Schade and Cams, 1962; Ikai, 1950; Tokizane, 1951; Waterland, Doudlah and Shambies, 1966) and children (Parr, Routh, Byrd and McMillan, 19 74) . Some therapists appear unaware of these data when they label the presence of the ATNR in children over 6 months old as “abnormal”. Such labeling of “abnormal” reflex presence is considered one sign of an immature or dysfunctional level of central nervous system integration (Fiorentino, 19 73; Rider, 19 73). Other therapists have modified their evaluation in response to the data suggesting a normal continuing in­fluence of the ATNR. They attempt to assess the magnitude of the response elicited rather than a simple response/no response dichotomy (Finocchiaro, 1974; Parmenter, 1975; Parr et al., 1974).