Psychosomatic differentiation in infancy. I. Autonomic activity in the newborn.

Abstract

Summary The results of the above studies demonstrate that individual differences in autonomic function exist in the newborn within the first few days of life. We agree with the conclusions of Richmond and Lustman on this. However, we note there are pronounced behavior differences of the several indices, and no one of them should be taken as the index of activity of the autonomic nervous system. Levels of homeostatic activity vary between individuals and within individuals as to partitions of the autonomic nervous system. Thus, single indices reflect levels of stability or lability, but do not necessarily correlate with other equally valid measurements. We disagree with the belief that uniformly deficient homeostatic regulations are characteristic of the newborn. To state that wide fluctuations are or are not characteristic of the newborn is to oversimplify the problem. What has been observed is that utilizing any single index of autonomic nervous system function, a given group of the newborn will show a normal distribution of activity with gradations from "rigidity" to "lability." However, the same individuals can show reversed degrees of homeostasis when another index of autonomic nervous system is used. It appears possible that every newborn infant may have at least one "vulnerable" component of the autonomic nervous system whose response to environmental stimulation shows a capacity for more lability. The question as to whether the patterns or responses observed are characteristic for the individual is debatable. Studies by Wenger, Sontag, Jost, and Lacey emphasize that in adults autonomic responses tend to be peculiar to the individual. This has recently been questioned by a study of the effect of stimuli variation on the responses.7 Richmond and Lustman appear to concur in the views of Wenger with application to the newborn. While this may be true, we feel that the evidence for the newborn is inconclusive at present. The use of stimulation as the method for eliciting individual differences is subject to error and can be very misleading. Our graphs show the variability of response obtained with repeated stimulation. To say that any one fluctuation is characteristic for the individual stimulated is erroneous, of course. Our studies show that during the periods of sleep, feeding, and random behavior certain consistent rank-order levels of activity exist for individuals within single systems (e.g., respiration). We have shown that a normal distribution is obtainable with levels of autonomic variability, but no evidence is available which shows that the extremes of this curve are characteristic for those individuals. It is certainly possible that the same newborn on successive days may reverse positions on this curve for either a single measurement or multiple indices. Certain personality constellations have been associated with specific psychosomatic diseases. The argument against this thesis has included the fact that similar emotional conflicts or personality structures are observable in different psychosomatic disorders in addition to being found in individuals with no evidence of organic dysfunction. The explanation for this may in part be found in the possibility that the vegetative dysfunction usually associated with specific emotional constellations may, for constitutional reasons, not be the "vulnerable" autonomic nervous system component available. It appears that lability or stability may be constitutionally characteristic for only a single or few components of the autonomic nervous system and it would require the fortuitous concomitance of an available "vulnerable" segment with the "proper" psychopathology for a psychosomatic disorder to occur. Whether "physiological regression" occurs or is part of this process must await further studies. The real problem is to trace the patterns demonstrated above and note whether change occurs and under what circumstances. Does channelization in those showing lability or widening in those showing initial stability occur? The nature of environmental elements affecting these processes must be studied to determine whether common factors in the interpersonal relationships can produce specific somatic alterations.