Infancy Movement Types Quiz

Types of Movement in Infancy

• Primitive reflexes are stereotyped movements or responses to stimuli.

• They are controlled sub-cortically and are dominant from the last 4 months of prenatal life to the first 4 months of postnatal life.

• These reflexes are involuntary responses to specific stimulation, often mediated by lower CNS centers.

• Newborns exhibit strong reflexes at birth, but these reflexes decrease in strength over time, disappearing around the fourth month.

• Primitive reflexes are the first neurological functions to develop, laying the groundwork for motor development.

• Failure of a reflex to appear or persist at the appropriate age can indicate a neurological issue.

• As higher centers of the CNS mature, primitive reflex activity transitions into volitional movement.

• Primitive reflexes never completely disappear.

• By four to six months of age, most primitive reflexes modify and no longer produce a stereotyped response.

• Reflexes can be categorized into three levels based on CNS maturation:

  • Spinal reflexes are the first level, involving initial muscle coordination patterns like flexion or extension. Examples include flexor withdrawal, extensor thrust, and crossed extension.
  • Brainstem reflexes, the second level, affect muscle tone in response to head or body positioning changes. Examples include tonic labyrinthine, ATNR, STNR, and positive/negative supporting reactions.
  • Midbrain reflexes, the third level, enable the infant to maintain balance and stability when changing positions during the first year of life. Includes righting reactions (automatic reactions)

Differentiating Reflexes from Spontaneous Movements

• Reflexes are responses to specific external stimuli, while spontaneous movements do not have an apparent external stimulus.
• Reflexive movements are typically specific and localized, while spontaneous movements are often nonspecific and generalized.

Appearance and Disappearance of Reflexes

• In typically developing infants, reflexes show a less specific response over time and eventually become non-stimulatable.

• A reflex appearing and disappearing at the expected average age indicates a typical developmental progress.

• Deviations in timing or execution of reflexes might signal developmental issues.

• Persistent reflexes after the average disappearance age may indicate a cerebral condition.

• A nonexistent or very weak reflex on one side compared with the other could suggest a lower motor neuron issue.

Postural Reactions

• Postural reactions (gravity reflexes) help infants automatically maintain posture in changing environments.
• Some postural responses help maintain an upright posture for breathing and feeding.
• Others help the infant with movement, such as rolling over.
• Postural reactions typically appear after the infant is two months old.
• These reactions are automatic and maintain the body's upright position through muscle tone adjustments.

Midbrain Reactions

• Midbrain reactions are automatic reactions, important for establishing a normal head and body relationship.
• They allow a person to assume normal standing positions and maintain stability during movement changes. These reactions develop in the first year of life.

Cortical Reactions

• Cortical reactions are mediated by the cortex, basal ganglia, and cerebellum.
• They appear with bipedal maturation.
• Divided into two types:
  • Equilibrium reactions maintain balance during body movement changes.
  • Protective reactions protect the body from falls by extending limbs, and develop up to age five.

Locomotor Reflexes

• Locomotor reflexes, like stepping, swimming, and crawling, appear before voluntary motor skills.
• Locomotor reflexes usually disappear for months before the infant develops the voluntary skills.

Test your knowledge on the types of movements in infancy and the significance of primitive reflexes. This quiz covers their development, duration, and implications for neurological health. Understand how these reflexes are crucial in transitioning to voluntary motor skills.