Using hand within the focal visual field.
Using a 3-D motion analysis of newborn’s arm movement, Von Hofsten 85 found that a newborn’s hand gets closer to a target when the baby fixates visually on the object compared to their movement when not fixating the object. That observation by Van Hofsten85 was supported by a work done by Brazeton, et al 94 . They found that 3 wk old babies showed a circular movement characterized by a series of extension-flexion patterns when attending to their mothers’ face. This pattern got disturbed to a jerky movement when infants lost the face-to-face interaction with their mothers.
This pattern was described as ‘swiping behaviour’ 73 . The former as well as the latter studies provide evidence for an early sensorimotor link between eye and hand. Visualization of the hand early in life is an important part of the coordination developed between eye and hand. Van der Meer et al 92 showed that spontaneous arm movements of newborn infants were decreased when occluding the arm from the infants’ sight. In that study infants were able to correct for small external forces applied to their arms only when the arms were visualized.
It has been reported that asymmetrical tonic neck reflex (ATNR) could be a mechanism to put the hand in the face side on the infants’ visual field, which may increase its probability of being seen and examined 95. Coryell & Henderson 95 also reported that the ATNR occurs most (56%) in the second month of life, which is when the central focal visual field starts to develop, so ATNR as they hypothesised that the reflex serves pointed to place the hand within the focal visual field. Von Hofsten 85 found that the number of forward arm movements on the face side of one week old infants was higher than the other side.
Furthermore, Van Kranen-Mastenbroek et al 96 were interested in seeing the results of spontaneous head turn on body posture (ATNR) of 3-8 days old newborns and its effect on lateralization of limb movements. They found that active head turn of the newborns included in the study was not followed by a dominant reaction pattern in any of the four limbs. However, their results showed that the frequency of limb movements of the face side were more than that of the skull side. They noticed that the infants spent more time in hand-¬mouth or hand- face contact of the hand ipsilateral to the face.
Visualization of the hand beyond neonatal and early infancy periods becomes important not to direct reaching but to correct the trajectory of the movement. For example, McDonnelled 99 fitted wedge prisms on 4-10 months old infants and noted that young infants in the study could not adjust the position of their hands to correct for the visual disortionof the prisms. As with young infants, older infants initially extended their arms toward the wrong place. However, when their hands entered their visual field, they corrected the trajectory of the hand and reached toward the correct location of the target.
Lasky 100 tested the effect of obscuring the hand from sight during a reach for infants who had just started to reach and those who had been reaching for a longer time (age range from 21/2 to 61/2 months). He found that the reaching movements of older infants were disrupted when the sight of the hand was obscured. Ashmead, et al 101 also reported that visualization of the hand by 9 months old infants is required only when making an adjustment to the reaching movement toward a moving illuminated toy presented in a dark room.
A final note related to the object used to eliciting upper limb movement is that infants tend to perform more reaches, when presented with a visual stimulus rather than an auditory stimulus; also the quality of reaching movement was better 66 . Three or two dimensional objects were found to elicit more voluntary upper limb movement than a blank visual field102 . Moreover, Bruner & Koslowski 103 found that the different sizes of presented objects had different effects on the infants arm and hand activity.
They found that small objects elicited hand movement appropriate to graspable objects, while with larger objects infants approached it with an open hand. McGuire & Turkewitz 104 reported that, unlike older infants, younger infants tend to withdraw from stimuli that are near, large and bright and approach those that are far, small and dim. Finally, Clifton et al 105 noticed more reaches toward objects presented within reach compared to objects beyond reach. Conclusion: These studies clearly indicate that infants can, from birth, process and react to stimuli. Studies that analyze infants’ reactions to taste, smell, sights and sounds prove this.
Several important assumptions can be made as a result of this study. First, infants are aware of various stimuli while in the uterus. The second assumption here is that babies can remember and recall. Anytime a baby responds to his mother’s voice, taste or smell, the idea is that the baby remembers it from his intrauterine experience. Thus, memory formation in neonates can hold many possibilities for work with both brain injured and non-brain injured infants. The ability for an infant to be prompted via his senses to move his head and arms holds great promise for rehabilitation.
While several options for rehabilitating brain-damaged infants, very few focus on physical therapy for newborns because of their lack of skilled control. Now, newborns can be enticed to make these movements through the introduction of external stimuli such as taste, smell and sound. Studies on newborn vision are more widespread. The first problems with focusing are well-documented. However, the rate at which a newborn learns to focus and track an object can also be manipulated by making sure that his hand is in his peripheral vision. This way, the infant can be encouraged to reach as a part of therapy for a brain injury.
Some research is underway to address this issue. Research with human neonates is focusing on applying quantitative brain imaging technology to newly born infants to determine associations between brain structure and motor-cognitive neurobehavioral development of normal children through five years of age and associations between brain injury or abnormality and disabilities within the motor and cognitive domains through five years of age. This research may lead doctors to make more use of intentional movement during the brain imaging instead of waiting for spontaneous movement in newborns.
More research is necessary to determine the role that this research will have on the rehabilitation of brain-damaged newborns. The sample set of these newborns is small, and researchers may have to wait years to see the results of their tests. Of course, much will depend upon the extent of the damage. However, with hope, the purposeful use of outside stimuli which the newborn both remembers and prefers from his time in the womb will entice him to make movements that could ultimately lead to his improvement or recovery.