Adaptive motor strategy for squatting in spastic diplegia

Automatico-voluntary dissociation in Angelman syndrome

“…However when he walks, while he has an uplifted,¯exed posture of the left arm, he has a downward¯exion attitude of his right arm. This automatico-voluntary dissociation is consistent with the idea that so-called`associated reactions' such as upper-limb posturing during ambulation depend on different pathways than those implicated in voluntary movements [2]. The resumption of right upper-limb dexterity also suggests a cortical reorganisation through functional connections which may re¯ect novel corticospinal projections [3], transposing kinematic invariants such as those demonstrated for the command of complex limb movements [4].…”

Head stability during whole body movements in spastic diplegia

“…Motor organization in cerebral palsy is largely determined by the persistence of these archaic patterns [10]. According to the concept of adaptive motor strategies, the motor patterns developed by children with cerebral palsy represent their solution for the underlying cerebral problem, re¯ecting priority management by the central nervous system [11]. Stability of head orientation appears to be an important priority for normal children but not for children with spastic diplegia.…”

Distinct multi-joint control strategies in spastic diplegia associated with prematurity or Angelman syndrome

“…This would require a stable frame of reference for collecting and integrating information from directional and orientation sensors, which may account for the high stability ensured to head angular orientation throughout the movements. Furthermore, feed-forward control is suggested by anticipatory deactivation of antigravity muscles, as previously described for various upper limb (Hufschmidt and Hufschmidt, 1954;Hoffman and Strick, 1995) and lower limb movements (Cheron et al, 1997;Dan et al, 1999;. This phenomenon ensures interruption of posture controlled by the antagonist muscles, facilitating prompt initiation of movement by a brisk activation of agonist muscles.…”

“…Kinematic analysis revealed differences in multi-joint control. Normal children performed the movement using the motor strategy recently described for children of 3±12 years (Dan et al, 1999) and adults (Cheron et al, 1997). It consists of coordinated hip, knee and ankle¯exion resulting in quasi-rectilinear trajec- tories of the body segments with conservative postural adjustment for trunk, head and arm orientation.…”

“…There has been a growing body of evidence that the study of multi-joint, whole-body movements involving change in posture can identify speci®c strategies of motor control (Stapley et al, 1998;. We therefore focused on the kinematics and lower limb electromyographic (EMG) activities associated with the movement of squatting, which has been studied previously in different populations (Cheron et al, 1997;Dan et al, 1999;.…”