Anticipatory Motor Planning and Control of Grasp in Children with Unilateral Spastic Cerebral Palsy

Abstract

Children with unilateral spastic cerebral palsy (USCP) have impairments in motor planning, impacting their ability to grasp objects. We examined the planning of digit position and force and the flexibility of the motor system in covarying these during object manipulation. Eleven children with a left hemisphere lesion (LHL), nine children with a right hemisphere lesion (RHL) and nine typically developing children (controls) participated in the study. Participants were instructed to use a precision grip with their dominant/less affected hand to lift and keep an object level, with either a left, centered or right center of mass (COM) location. Digit positions, forces, compensatory torque and object roll where measured. Although children with USCP generated a compensatory torque and modulated digit placement by lift-off, their index finger was either collinear or higher than the thumb, regardless of COM location, leading to larger rolls after lift-off especially for the RHL group. The findings suggest that while the kinetics of grasp control is intact, the kinematics of grasp control is impaired. This study adds to the understanding of the underlying mechanisms of anticipatory planning and control of grasp in children with USCP and may provide insights on how to improve hand function in children with USCP.

Correlation between Cognitive Abilities and Fine Motor Skills in Children with Hemiparetic Cerebral Palsy

“…According to the definition of motor planning, it is a cognitive process in which a patient plans and carries out a series of suitable movements in the direction of an object while keeping in mind both the forward internal model and the information that is now accessible. The development of one's motor abilities and experience with movement both influence one's capacity to create internal representations of a physical act (17)(18) .…”

Neural Correlates of Impaired Grasp Function in Children with Unilateral Spastic Cerebral Palsy

“…Children with USCP display anticipatory control impairments during grasp (e.g., [5,12,15,73]. There are 'global planning' impairments in anticipatory control of action during functional tasks where anticipatory control impairments are displayed in both the more and less affected hands (e.g., [15,73,74]).…”

“…Children with USCP display anticipatory control impairments during grasp (e.g., [5,12,15,73]. There are 'global planning' impairments in anticipatory control of action during functional tasks where anticipatory control impairments are displayed in both the more and less affected hands (e.g., [15,73,74]). For example, the manner and location of which they grasp the object with their less affected hand may not be biomechanically optimal for keeping an asymmetrical object from tilting after it is lifted, as they keep their thumb collinear or lower than their index finger [15].…”

“…There are 'global planning' impairments in anticipatory control of action during functional tasks where anticipatory control impairments are displayed in both the more and less affected hands (e.g., [15,73,74]). For example, the manner and location of which they grasp the object with their less affected hand may not be biomechanically optimal for keeping an asymmetrical object from tilting after it is lifted, as they keep their thumb collinear or lower than their index finger [15]. However, the scaling of force development is effector dependent, as the impairments are lateralized to the more affected hand ( [11,68,75,76]).…”

“…The paradigm was first used by Johansson and Westling in a series of studies starting four decades ago to examine cutaneous afferent input during grasp [7][8][9][10]. Since then, this approach has been used in many patient populations, including children with USCP to examine various aspects of grasp such as anticipatory control and adaptation of fingertip forces (e.g., [4][5][6][11][12][13][14][15]).…”