Studies of Cristospinal Reflexes (Laterotorsion) II.:Caloric Nystagmus and Laterotorsion in Normal Individuals

A previously reported method for simultaneously recording the cristo-ocular (nystagmus) and cristo-spinal (laterotorsion) reflexes is reviewed. Calorically induced turning of the head, neck and body produced changes in weight on two pneumatic systems introduced beneath the head of supine individuals, which was expressed as laterotorsion. This recording was made in addition to the usual nystagmus. Such records were collected, studied and subjected to statistical analysis.Spontaneous laterotorsions of normal individuals were always less than 269 g after two minutes. Caloric laterotorsion was always in the direction of the slow component and averaged 828 g.Maximum laterotorsion and nystagmus were fairly consistent for a given individual but varied between individuals.A statistical analysis revealed a significant correlation between vertigo and laterotorsion but not between vertigo and nystagmus.The lack of quantitative correlation between nystagmus and laterotorsion was evidenced by unequal patterns of behaviour which expressed itself as (1) lack of correlation between maxima of the two reflexes, (2) unequal time for development of the maxima and (3) unequal duration of the nystagmus and of the laterotorsion.Light decreases both nystagmus and laterotorsion. The decrease of laterotorsion was less than that of nystagmus.