Kinematic and kinetic analysis of finger-handmotor function in children with central movement disorders

Objective: Handmotor function plays a central role for the prognosis in everyday life in children with movement disorders. The present study examines various paradigms for kinematic and kinetic testing and their diagnostic relevance, also for therapy monitoring, in children with spastic and dyskinetic cerebral palsy (CP) and in children with ataxia.

Methods: 140 children with central disorders of movement were quantitatively examined. The apparatus for the examination consisted in a hand grip object (200g, incl. force sensor, accelerometers), a precision scale, a small pinch grip object (20g). The test battery consisted of: maximum grip force (hand grip), reflectory force adaptation to sudden loads, fastest isometric force changes, lifting of the hand grip object, repetitive vertical movements with the hand grip object (ca. 30cm) in different frequencies, hand tapping, finger tapping, aiming (20cm), fastest single finger movements. Elementary drawing movements were examined by a digitizer tablet (small/big circles as fast as possible, small/big lines as fast as possible).

Results: Various pathological patterns could be found and some paradigms were dependent on severity. More than 90% of the children had pathological elementary functions. Ataxias had various kinematic and kinetic disturbances. Specific changes under therapy are shown.

Discussion: The presented objective motor diagnostic approach could be an important aid for therapy monitoring and rehabilitation planning in children with movement disorders.

Keywords: cerebral palsy, hand motor function, kinematics, force dynamics