Sunday, November 20, 2011
Cerebral Palsy and the Pediatric Evaluation
Part 2: The Developmental Process: Primitive and Postural Reactions
The second installment in this series on Understanding the Pediatric Evaluation revolves around two fundamental elements of the developmental process that are critical in the greater understanding of the long-term rehabilitation plan. Primitive and postural reactions are characteristic of critical early development that effectively signal progression and movement towards improved development. They are the easiest, earliest, and more frequently used tools in assessing neurological and motor development in newborns and infants.
Primitive reactions are mediated in the brainstem and are fully present at birth. They are characterized by automatic movement patterns that become more difficult to elicit after the first 4-6 months of life. Some examples below:
Postural Reactions develop following / during the disappearance of the primitive reactions. They can be considered voluntary actions that are produced by multiple sensory and structural inputs. They are complex motor responses to afferents like tendons, joints, skin, internal organs, and even the eyes and ears. They are characterized by predictable postural adjustments to specific applied sudden changes in position. As the child develops, the postural reactions (or postural performance) improve and manifest in more comprehensive ways as he /she ages. Some examples below:
The understanding of these reactions is fundamental in the effective and accurate assessment of the success of the rehabilitation protocol. To be more precise, Infants with cerebral palsy have been known to manifest persistence or delay in the disappearance of primitive reflexes and pathologic or absent postural reactions. Therefore, the emergence of postural reactions (and the reduction of primitive reactions) is the primary treatment goal and thus any protocol that promotes this will ultimately contribute to improved function.
Part 1 of this series identified the need to place primary focus on the developmental age rather than the chronological age. Although not age appropriate, the persistent appearance of primitive reactions in older children is simply an indication of their current status and placement along the developmental path. It should also be remembered that the actual "manifestation" of these primitive reactions may look significantly different in an older child than a 6 month old. The structural proportions (length, weight, mechanics, torque, etc) are very different, therefore the same "reaction" may subjectively appear to be more severe or, at times, appear to be something completely different.
What does this all mean and how does it apply to my understanding of Cerebral Palsy? The answer is quite simple and straight-forward: the developmental process is something that cannot be circumvented or skipped. If the child with Cerebral Palsy continues to manifest primitive reactions in conjunction with the absence of postural reactions,any expectations of higher order function (crawling, independant sitting, gross / fine motor skills) is unrealistic. Rather than a message of "gloomy reality", the fundamentals of the development of the human organism will allow you to understand the "right path" and therefore effectively reduce any unecessary anxiety and worry associated with the unknown. More importantly, it clearly identifies those interventions that are essentially "shortcuts" along the path...which initially produce increased levels of hope and expectation, but in the end reduce maximum potential.
I apologize for the relatively longer post...it has been quite the challenge to even keep it this short! The third installement: Cerebral Palsy and the Pediatric Evaluation: A Case Study Report will blend the theoretical elements of part 1 and 2 and demonstrate their application in a practical examination of the progress of an actual CP child. I hope that it achieves my goal of creating a link and close the loop of understanding.