Published on : 26 November 20214 min reading time
STAGES OF PSYCHOMOTOR DEVELOPMENT IN CHILDREN
In children, motor skills are inherent to the corticospinal system and the subcorticospinal system (lower system). The latter matures earlier and in an ascending fashion, unlike the corticospinal system, which matures later and in a descending fashion. If the subcorticospinal system is displayed from the last three months of fetal life, the superior system only expresses itself at the beginning of birth, gradually suppressing reflex motricity. This is concretely translated by the installation of a controlled, rapid and precise motricity, followed by a passive tonus of the limbs which gradually relaxes.
DEFINITION OF REFLEX MOTRICITY
These are primary motor reflexes occurring in the first months of the child, and whose presence indicates a good functioning of the subcortical system. They are observed during the examination of the infant born at term, and are however destined to disappear between the 2nd and the 4th month. For this reason, if these so-called archaic or primary reflexes persist beyond the 5th month, it could be pathological.
The motor reflexes are the sucking reflexes to the stimulation of the peribuccal areas, manifested by the orientation of the infant’s lips. Also the grasping reflex, provoked by the stimulation of the palm of the hands (the infant grasps firmly, with a strong flexion of the fingers), the sucking-deglutition allowing him to suck. Automatic walking, the cardinal point reflex that occurs when the cheek is tickled, and the Moro reflex are all examples of motor reflexes.
PSYCHOMOTOR DEVELOPMENT OF THE CHILD: PASSIVE AND ACTIVE TONE
The passive and active tone of the newborn are systematically examined neurologically at birth. The evolution of the infant’s tone is in the caudocephalic direction.
THE PASSIVE TONE
The evaluator can assess the passive tone of a newborn by flexing the joints of the upper and lower limbs in relation to each other in a fetal position. He will analyze the spontaneous quadriflexion posture of the limbs.
Other maneuvers allow to appreciate it like the scarf sign (no crossing of the elbow of the median line at the approach of a hand towards the contralateral shoulder), or the analysis of angles. The popliteal angle or angle of extension of the leg on the thigh will be less than or equal to 90° and increases to 180° at 8 months. The heel-ear angle is less than or equal to 90°, etc.
THE ACTIVE TONE
The examination of the active tone is done by examining the straightening of the head, by examining the way the newborn stands on his legs when held under the arms, or when standing. The same is true when the baby is supported on the soles of his or her feet.
In general, tone changes rapidly as a function of maturation. It goes from a stage of physiological hypertonia (at birth) to a stage of hypotonia from the 8th month. The psychomotor development or gross motor skills of the child depends, therefore, on the child’s ability to control his or her axial tone.
This leads to independent walking, which generally takes place between 12 and 13 months of age. It is the evolution of tone that allows the child to hold his head at 3 months, to sit without any support at 7 months, or to stand up between 10 and 12 months. The disappearance of primary reflexes, including grasping in this case, gives rise to a contact grasp between 4 and 5 months. This still evolves into symmetrical prehension and lateralization until the child is 4 years old.
The evaluation of psychomotor development in children will necessarily focus on motor acquisitions, as well as their cognitive abilities. By cognition, we mean reasoning, intelligence, perception, memory, language, etc. At the same time, these analyses aim to ensure that the child’s brain growth is normal. It is important to note that a child’s development is the result of genetic factors and his or her environment.