Design and development of a sensorized wireless toy for measuring infants' manual actions.

The development of grasping is an important milestone that infants encounter during the first months of life. Novel approaches for measuring infants' manual actions are based on sensorized platform usable in natural settings, such as instrumented wireless toys that could be exploited for diagnosis and rehabilitation purposes. A new sensorized wireless toy has been designed and developed with embedded pressure sensors and audio-visual feedback. The fulfillment of clinical specifications has been proved through mechanical and electrical characterization. Infants showed a good grade of acceptance to such kind of tools, as confirmed by the results of preliminary tests that involved nine healthy infants: the dimensions fulfill infants' anthropometrics, the device is robust and safe, the acquired signals are in the expected range and the wireless communication is stable. Although achieved only through preliminary tests, such results confirm the hypothesis that this typology of instrumented toys could be useful for quantitative monitoring and measuring infants' motor development and ready to be evaluated for assessing motor skills through appropriate clinical trials.

Longitudinal study of unimanual actions and grasping forces during infancy.

Learning to grasp an object is an important milestone in neurological development during infancy. Several studies report development of reaching in infants but less attention is devoted to reaching with successful grasping and to development of grip force. This study investigates, in the first weeks of life, the development of palmar grasp both for assessment of unimanual/bimanual grasping actions in centrally and laterally placed objects and for measurement of exerted power grip force. We longitudinally examined ten infants from 18 weeks to 41 weeks, at 2-weeks intervals, with a toy placed in three positions (body midline, ipsilateral and contralateral shoulder). Our main aim was to study this development through an ecological approach. This was possible thanks to the use of the "biomechatronic gym", a new platform purposively developed for measuring reaching and grasping forces. These longitudinal trials showed a good level of acceptance and involvement by infants of the entire system. The results demonstrated a significant increase in unimanual power grip force between the 18th and 30th week followed by a flat period until the 41st week; we also ascertained an early tendency to play bimanually with centrally and laterally placed objects with a subsequent increase in all ages of unimanual successful power grasping both for central task and midline crossing. These developmental changes may be, in part, related to organism constraints such as maturation of the corticospinal tract.