Early development of head movements between birth and 4 months of age: a longitudinal study

The control of head posture and movement play a significant role in the early development of motor skills. However, a detailed kinematic study charting this development is currently lacking. Hence, the authors performed a longitudinal study of 18 infants between birth and 4 months charting changes in head posture and movements when tracking a visual object. The results showed that beyond 2 months, the head was more often held at the body midline and this was accompanied by an increase in the number, extent, and speed of head movement. Further, it was found that head movements were organized into movement units. Movement units initially increased in number, but after 3 months decreased in number and increased in duration, especially after peak velocity. This more symmetrical profile velocity points to more controlled head movements after 3 months of age.