Newborns have a variety of unconscious motor response patterns to specific stimuli during the first weeks and months of life. The grasping reflex is one of these and consists of a forceful grasp with the hand when touched and pressure is applied to the palm. The toes and the sole of the foot also curl in an implied grasping movement when the sole of the foot is touched. The grasping reflex probably originally served reflexive clinging to the mother.
What is the grasping reflex?
Newborns have a variety of motor reflexes at birth. These are unconscious behaviors that are triggered by specific sensory stimuli. Newborns have a variety of motor reflexes at birth. These are unconscious behavioral patterns triggered by specific sensory stimuli. The development and disappearance of the reflexes is less dependent on the time of birth, but rather on the time of conception (conception age). The grasp reflex can be divided into the hand grasp reflex and the foot grasp reflex, which develop and disappear independently of each other. When the newborn’s palm is touched and pressure is applied, it responds unconsciously with a firm grasping movement of the fingers (fist closure). The foot grasp reflex is analogous to this. However, the foot grasp reflex consists only of the curvature of the toes and flexion of the sole of the foot when touched and pressure is applied to the sole of the foot, i.e. only an implied grasping movement. The grasping possibilities with the feet have regressed in humans developmentally. The hand and foot grasp reflexes are detectable from about the 32nd week of conception and disappear for the hand by the 9th month of life at the latest, and the foot grasp reflex regresses by the end of the first year of life at the latest, or when the child learns to walk upright.
Function and task
In newborns, the central nervous system, especially the cerebrum, is not fully developed and not yet fully functional, because otherwise the size of the head would make the birth process even more problematic. Many necessary skills – especially motor skills – that later take place consciously at will are replaced by unconsciously controlled reflexes, which are comparable to self-controlling regulatory circuits and are triggered by certain stimuli. The most important function and use of the grasping reflex, especially the hand grasping reflex, probably consisted during an earlier developmental stage of man in the fact that the newborn could actively hold on (cling) to the mother or to rod- or rope-like objects. This temporarily left the mother or another person with both hands free to do other things. The foot-grasping reflex probably also served to hold on and cling, but today it functions only in a rudimentary way because the mobility of the foot’s middle bones and the length of the foot’s toes as well as the musculature have regressed in the course of human developmental history. While the strong hand grasp reflex is still fully functional today and the baby can hold on to bars, ropes or even the mother’s clothing during the first months of life, the foot grasp reflex no longer fulfills this function. However, it can be used to maintain the rudimentary possibility of grasping with the foot through appropriate exercises during the transition to voluntary motor activity. The grasping reflex serves less for the reflex-like holding of objects than for the possibility of holding oneself. The foot-grasping reflex can also prove troublesome if it does not regress during the learning phase for upright walking. The child then has difficulty putting weight on the whole sole of the foot because instead he or she constantly wants to grasp with the foot and tends to try to stand and walk on tiptoe.
Diseases and complaints
The early infant reflexes in newborns – also called primitive reflexes – serve a variety of purposes. For example, some of the reflexes are important only prenatally, to protect the baby from entanglement of the umbilical cord with the limbs before birth and to set the baby up for the best possible position for birth by making certain movements of its own. Although the grasping reflex is not of primary importance for survival in humans today, it is still important that the reflex is already mature at birth.An only weakly developed or completely absent grasping reflex indicates serious direct muscle or joint diseases or neuronal maldevelopments, which should be clarified without fail. As a rule, other motor reflexes are also affected in the case of a non-developed grasping reflex. Normally, within the first months of life, the primitive reflexes are gradually overridden and replaced by conscious motor actions. This occurs through increasing maturation of the neocortex and myelination of the afferent nerves, which can report sensory messages to the central nervous system more rapidly than is possible via messages from the reflex arches. The degradation of the grasping reflex as well as the degradation of other reflexes only occurs according to the rules if the child trains the degradation through constant multisensory learning, through conscious motor actions (e.g. playful). In some children and even adults, remnants of the primitive reflexes are retained, which can lead to disturbed learning behavior, attention disorders and behavioral problems. Also arithmetic, reading and spelling deficiencies are partly attributed to a lack of breakdown of certain primitive reflexes. For example, if the foot-grasp reflex does not regress as a result of the toddler’s attempts to walk, learning to stand upright and walk is extremely difficult. The foot repeatedly attempts to arch inward in an imaginary grasping motion when weight is placed on the sole of the foot.
