Development of supination-pronation movements in normal children.

Abstract

In 219 normal children aged from 4 to 9 years it is shown that several features of hand-arm supination/pronation movements do not develop with age at the same rate. Ipsilateral synkineses as well as associated mirror movements decrease and diadochokinetic movements are performed in a more regular way. Bimanual mirrorwise movements are well performed at an early age, while bimanual alternate movements have a slower development at the ages under study. It is argued that the developmental rate of bimanual alternate movements might partly represent the maturation of interhemispheric connectivity and contributes to the clinical judgment of development in a different way from the development of unimanual movements. It is thought that each characteristic of these movements has its own nervous substrate.