Hand Function 7-24 Month Period

Development of Hand Function

Development of hand function for infants occurs in two processes; cascades in development and perception-action loops with embedded exploration and selection.

Cascades in Development

Hand development in infancy is formed by previous learned skills. New skills are a combination of established development with new skill acquistion. Hand function begins by spontaneous movement transitioning into intentional goal-directed play.

Perception-Action Loops with Embedded Exploration and Selection

Infants will use repeated trials to learn new skills. With each opportunity they learn how to vary their movement to attain success. Some patterns of movements will be fruitful than others. Performing an action repetitively allows for different sensory feedback as a consequence of their movement. This process of executing various movement patterns over repetitive trials refers to the perception-action loop.

Perception

The way in which we gather information about the events within the environment (the physical structure and the events occuring) is referred to as perception. We attain this information through an active process of the brain recognising patterns from the steady flow of sensory information. Some of the ways in which we perceive sensory information is through tasting, feeling, looking and listening. The use of hands provides the sensory function of feeling to learn about properties of the object.

7-12 Month Period

The purposes of the hand during this period is trifold:

1. As part of the postural and locomotor systems
   • learning to balance in sitting, crawling and buttock shuffling, cruising
2. For communication and in social interactions
3. For picking up, moving and manipulating objects
   • to explore their different properties and what can be done with them

Hand-Object Actions

During the 7-12 month time period, infants will use their hands to interact with objects with the varied complex actions:

• shaking
• banging
• patting, poking, stroking, flapping with the fingers
• turning objects over
• passing from one hand to the other
• throwing and dropping objects
• picking up, moving and dropping small and large objects

Grasp Patterns

As the infants learn to manipulate objects with the above hand-object actions, they also learn which grasp is best suited for each object. Repetitive trials allows them to find a finger pattern that is best suited to the size and shape of different objects.

Grasp patterns commonly seen during this period:

• Hook grasp
• Power grasp
• Palmar grasp,
• Circular grasp
• Chuck grasp
• Key grasp