The Cranial Rhythmic Impulse and Excessive Crying of Infancy

Background: Osteopathic physicians believe that the birthing process causes cranial dysfunction that may be manifested in somatic symptoms, one of which is excessive crying of infancy. Cranial dysfunction can be determined by assessing the cranial rhythmic impulse (CRI). Objective: The objective of this study is to examine whether an abnormal CRI is associated with excessive crying of infancy. Design: Full-term infants in the well-baby nursery of an urban public hospital in the Bronx, New York were enrolled. Two (2) osteopathic physicians independently measured the CRI in infants before discharge. One (1) osteopath repeated the CRI measurement at 2 weeks. At 6 weeks, an investigator blinded to the CRI and birth data assessed infant crying using the modified Ames Cry Score via telephone interview with the primary caretaker. The caretaker was also asked about maternal stress, use of home or cultural remedies, and the infant's diet. The main outcome measure was the presence of excessive crying. Results: One hundred and thirty-nine (139) patients were included in the final sample. The overall incidence of excessive crying was 41.7%. Excessive crying was associated with an abnormal CRI at 2 weeks (p < 0.001) but not with the CRI at birth (p = 0.23). Infants with an abnormal CRI at 2 weeks were 6.8 times (95% confidence intervals 2.2, 20.6) more likely to develop excessive crying than infants with a normal CRI. Infant diet was independently associated with excessive crying. Inter-rater agreement for CRI measurement was 0.70 using the κ statistic. Conclusions: These data suggest that an abnormal CRI at 2 weeks of age may be associated with excessive crying.