development of manipulative skills

Overview of Manipulative Skills

  • Manipulative skills involve motor skills related to object control.

Key Components of Manipulative Skills

  • Reaching

    • Definition: Extending the arm or hand towards an object.
    • Requires coordination and control.

  • Grasping

    • Definition: The action of holding or seizing something with the hand.
    • Involves the use of hand strength and grip adaptation.

Pre-Reaching

  • Pre-Reaching
    • Definition: The uncoordinated extension of an arm towards an object within the visual field.
    • Reflex involved: Reflex observable around 18 hours of age.
    • Onset: At birth.
    • Integration Age: 4 to 6 months.
    • Stimulus: Head raising.
    • Response: Attempting to reach.

Environmental Constraints on Reaching

  • Factors influencing reaching:
    • Physical constraints: Objects’ size and shape, individual hand size, and arm strength.
    • Cultural context: Variation in object handling based on setting (e.g., holding a wine glass differently at home versus a restaurant).
    • Motivational factors: Personal motivations or fears influencing whether to reach for an object.
    • Environmental visibility: Differences in reaching capability in darkness versus light.

Development of Reaching Skills

  • Infants initially knock objects over due to lack of experience.
  • Children begin acquiring skills necessary to configure their hands correctly before reaching.
  • Adults typically prepare their hands (shape) to the object before reaching.
  • Importance of visual-motor mapping: Aligning gaze to the object to facilitate reaching.

Grasping and Scaling

  • Grasping tends to remain a stable skill throughout life and does not typically need to be relearned.
  • Object size is more critical than shape for grasping.
  • Development of Grips:
    • Power grips are learned before precision grips.
    • Definition: Power grips use the entire hand for forceful object movement.
      • Types of Power Grips:
      • Palmar grasp: No thumb involvement.
      • Radial grasp: Thumb involved.
      • Cylindrical grip: Holding an object cylindrical in shape.
      • Spherical grip: Holding a round object.
      • Hook grip: Holding something with fingers like carrying a suitcase.
      • Hammer grip: Control exerted from the fingers rather than the palm.
    • Precision grips: Thumb and fingers used for fine manipulation.
      • Types of Precision Grips:
      • Radial digital grip: Using fingers for holds.
      • Inferior pincher grip: Pad to pad grip squeezing together.
      • Superior pincher grip: Tip to tip grip.
      • Three jaw chuck: Holding an object with three fingers.
      • Lateral prehension: Pinching between finger and thumb.
      • Lumbrical grip: Holding an object with palm contact.

Lateral Reaching and Object Transfer

  • Movement patterns in infants involve bilateral reaching.
  • Steps/ranges of acquisition include:
    • Holding an object with one hand.
    • Transferring an object across the midline (from one hand to another).
    • Reaching across the body.
    • Concurrently gripping more than one object.
  • Skill development includes practical applications, such as a child passing an object across their body.

Age-Related Changes in Reaching and Grasping

  • Around age 50, adults experience:
    • Decreased speed in reaching tasks.
    • Diminished grip strength, often linked to individual functional constraints rather than aging alone.

Catching Skills

  • Catching Definition: Gaining control of a moving object by intercepting it with hands or an implement (glove, racket, etc.).
  • Catching is typically developed after skills in throwing and kicking.
    • Proficient catchers prepare hands to receive the object with 'give.'
    • **Catching Techniques: **
    • Fingers point up for high objects; fingers point down for low objects.
    • Pre-Catching Stage: Initial uncoordinated actions at 8-9 months.
  • Skill Development:
    • By 2 years old, children can catch a large, conveniently placed ball.
    • By ages 3-6 years, children exhibit improved techniques: moving the body, giving with the hands, and correctly adjusting fingers.

Coincidence Anticipation

  • Related to understanding spatial-temporal perception in relation to movement.
  • Coincidence anticipation: The ability to time movements to coincide with the arrival of a moving object.
    • Development through childhood influences catching abilities, accounting for factors like social exposure to catching activities.

Task Constraints in Catching

  • Factors affecting catching include:
    • Complexity of movements needed to catch an object (requires coordination).
    • Size of the ball (larger objects easier to catch).
    • Object trajectory (vertical and horizontal components).
    • Background contrast affecting visibility of the ball relative to the surroundings.
    • Speed of the object and how consistent the motion is.

Key Observations on Aging and Catching Skills

  • Older adults face physical declines affecting catching abilities because of:
    • Motor skills and precision reductions.
    • Changes in sensory perception can diminish performance as experienced with some tasks.
    • Greater difficulty multitasking or planning movements effectively.