Neonatal Primitive Reflexes: Assessment and Integration Milestones

Understanding Primitive Reflexes in the Newborn

Primitive reflexes in the newborn (NB) are stereotyped, involuntary responses that reveal the priority of focal subcortical centers governing tone and movement during the transitional state of cortical immaturity. Most of these reflexes (normal reflexes) are present in the NB and disappear spontaneously as the Central Nervous System (CNS) matures. Their integration is fundamental for the development of voluntary, active, and functional mobility, usually occurring during the first year of life.

Suckling Reflex

Procedure: When the baby is relaxed and supine, the index finger is introduced slightly between their lips.
Response: An automated suction response is elicited.
Integration: This reflex typically disappears around two months of age and is crucial for feeding.

Rooting Reflex (Orientation)

Procedure: Stimulate the lip area with a finger.
Response: The child purses their lips and turns their head toward the examiner's finger, seeking the stimulus. If the child is hungry, the reflex is more pronounced.
Integration: It disappears around two months and is related to feeding.

Palmar Grasp Reflex

Procedure: The child is placed supine. The examiner places their index finger transversely across the child's palm.
Response: The child closes their hand tightly. This reflex appears with great intensity in the newborn.
Integration: It gradually diminishes as it integrates into active manipulation, disappearing completely between 3 and 4 months.

Plantar Grasp Reflex

Procedure: Pressing the first interosseous space of the sole of the foot.
Response: A powerful flexor response of the toes is elicited.
Integration: Appears in normal children and disappears during the third quarter of the first year, correlating with the onset of standing.

Positive Support Reflex (Primitive Standing)

Procedure: The child is held upright with their feet touching a flat surface (e.g., a table).
Response: The child responds by straightening their legs and bearing weight momentarily.
Integration: This reflex can be obtained from the newborn up to 2–3 months of age.

Stepping Reflex (Automatic Walking)

Procedure: Building upon the Positive Support Reflex, the child is inclined slightly forward.
Response: They will make alternating stepping movements as if walking.
Integration: This reflex typically disappears by the 4th week of life.

Placing Reflex (Overcoming Obstacles)

Procedure: Lightly stimulate the dorsum (backs) of the foot against the edge of a table (tested one foot at a time).
Response: A response of flexion in the lower limb is obtained, causing the foot to lift and place itself onto the surface.
Integration: Persists until 4–6 weeks of age.

Moro Reflex (Startle Reflex)

Procedure: The examiner supports the child's head and allows it to momentarily drop backward while the child is supine (a drop of only 1 or 2 cm off the table).
Response: The child responds by extending their arms in a broad, embracing movement, with hands open and fingers abducted. Leg extension may also occur, though this is variable. The movement is often accompanied by crying.
Integration: Present at birth but diminishes in intensity and usually disappears by 2–3 months.

Galant Reflex (Truncal Incurvation)

Procedure: The baby is held prone, suspended by the abdomen. The examiner strokes the paravertebral area (along the spine) from D4 (scapula level) down to L2 (lower back).
Response: The child responds with a curvature of the trunk toward the stimulated side. The arm and leg on the side of the curvature abduct (move away), while the contralateral limbs adduct (approach).
Integration: This reflex should disappear between the 4th and 5th month, correlating with the development of trunk rotation and extension.

Crossed Extension Reflex

Procedure: The child is placed supine. The examiner holds one leg in extension and firmly strokes the sole of the foot from heel to toes.
Response: The opposite leg responds in three phases:

1. Flexion of the hip and knee.
2. Extension of the hip and knee.
3. Adduction of the leg toward the midline, often with toes fanned.

Asymmetrical Tonic Neck Reflex (ATNR)

Procedure: The child is placed supine with limbs aligned. The examiner sharply turns the child's head to one side.
Response: Extension of the limbs on the side the face is turned toward (the 'fencer's pose'), and flexion of the contralateral limbs (upper and sometimes lower).
Integration: In normal children, this reflex should be integrated (eliminated) within three months.

Prone Head Righting Reflex (Survival)

Procedure: Place the child prone with the head straight down.
Response: The child responds by turning the head to one side to clear the airway and avoid suffocation.
Integration: This is a crucial survival reflex present at birth.