FAQ: 4
What are various postural reflexes and what is their clinical significance ?
Postural reflexes represent complex motor responses to a plurality of afferences such as the joints, the tendons, the muscles, the skin, the inner organs, telereceptors (eye) and otoreceptors (ear), and of course the labyrinth.
They are characterized by a certain stereotyped posture of the trunk, head, and extremities (i.e., the entire body), when the examiner attempts a strictly defined sudden change of position .
These Reflexes
- can determine level of neurological maturation.
- are age-specific in normal, healthy infants.
- Severe deviations from normal time frame may indicate neurological immaturity or dysfunction
1. SYMMETRICAL TONIC NECK REFLEX:
| Stimulus | S: The symmetrical tonic neck reflex is evoked by flexion or extension of the neck R: On raising the head of a kneeling child, extensor tone increases in the arms, and flexor tone increases in the legs |
| Duration | Birth – 3-4 months |
| In Normal infants | When they raise the head and shoulders in the prone: it helps them to support themselves on the arms and to get on to hands and knees. The reflex disappears when they learn to crawl, a movement which demands independence of movement of the limbs from the position ofthe head |
| In cerebral palsy | The reflex is overactive. The child can only extend his arms in kneeling when the head is raised. The legs are then fixed in flexion. As long as the head is raised the child is unable to extend his legs. If the head is lowered, the arms flex, the legs extend and the child falls on this face, so that he is unable to crawl. |
2. ASYMMETRIC TONIC NECK REFLEX:
| Stimulus Response | S: head turned to one side R: the arm extended to the same side. The contralateral knee is often flexed. |
| Duration | normally disappears by the age of 2 or 3 months |
| Clinical significance | The reflex is more marked in spastic babies and persists longer than in normal babies. The reflex is partly responsible for preventing the child rolling from prone to supine or vice versa is the early weeks |
3. PARACHUTE REFLEX:
| Stimulus Response | S: holding the child in ventral suspension and suddenly lowering towards the couch. R: arms extend as if to protect him from falling |
| Duration | Appears at 6 to 9 months – persists throughout life. |
| Clinical Significance | In children with cerebral palsy the reflex is absent or incomplete owing to the strong flexor tone in this position. In a child with hemiplegia the reflex would be normal on the unaffected side. |
4. LANDAU REFLEX: (VERTICAL SUSPENSION) :
| Stimulus Response | S:child is held in ventral suspension R: the head, spine and legs extend S: when the head is depressed, R: the hip, knees and elbows flex. |
| Duration | Appears by3 months – disappears by 1 year |
| Clinical significance | Absence of the reflex over the age of 3 months is seen in cases of motor weakness, cerebral palsy and mental subnormality |
5. RIGHTING REFLEXES:
Appear in a definite chronological order.
Enable the child to roll from prone to supine and supine to prone. They help him to get on to his hands and knees and to sit up.
Responsible for the ability to restore the normal position of the head in space and to maintain the normal postural relationship of the head, trunk and limbs during all activities.
- Neck righting reflex.
This is present at birth and is strongest at the age of 3 months. Turning of the head to one side is followed by movement of the boxy as a whole.
- Labyrinth righting reflex acting on the head.
This is present at 2 months of age, and strongest at 10 months. It enables the child to lift the head up in the prone position (when 1 to 2 months old) and later when in the supine position.
- The body righting reflex, acting on the body.
This appears at 7 to 12 months. It modifies the neck righting reflex and plays an important role in the child’s early attempts to sit and stand.
The child cannot turn to one side as the neck righting reflex is inhibited by the labyrinth reflex. He cannot raise the head in the supine or prone position.
He has great difficulty in turning over and sitting up.
In severe cases of cerebral palsy, when the examiner attempts to flex the child’s head, holding the back of the head, there is strong resistance to flexion: the head will extend and the whole back may arch.
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