Associated movements as a measure of developmental age.

Fifty normal kindergarten and 50 first-grade children were examined three times at six-month intervals for synkineses to stress gaits and mirror movements to finger lifting, finger spreading, and timed motor maneuvers. Motor signs in the age-sensitive range showed substantial individual differences between children of the same chronological age. The frequency of associated movements changed reliably in the expected direction over a 12-month period, and within each domain of neuromotor function the individual motor signs conformed to a stable sequence of developmental stages. It is concluded that age-appropriate motor signs for associated movements are a reliable measure of developmental age, in contrast to chronological age, among elementary-school children.