Biomechanical

Possible Biomechanical and Neuro Mechanisms for Flexible Compression Bracing: Food for Though!

Though the insights shared here can certainly be considered highly speculative, they are offered as possible mechanisms for the functional changes which we have observed in hopes of stimulating more thought and exploration in this area. At a wonderful 3-day course in February 1996 called "The Brain in 3-Dimensions", instructor Shelby Clayson, MS, OT casually shared some information during a break which has profoundly stimulated my thinking. My question to her was concerning any neurophysiological connection between deep pressure and proprioception. Her response both astounded and excited me! Not only were proprioception and deep pressure specific somatic inputs to an organization within the CNS designed for environmental exploration and learning, but this system also included vibration and precise touch as additional somatic inputs. An alternate organization designed for survival and protective functions included inputs of light touch and pain. Proprioceptive feedback deficits can be because of a primary deficit or because of inconsistent and poorly coordinated muscle activation disrupting the sensory feedback loop. Could it be that persons with these deficits are able to receive helpful information from vibratory and deep pressure receptors that enable improved functional movement control? Is this the link that makes Flexible Compression SPIO Bracing change functional control so quickly for some individuals?

If it is so, and my experience and intuition makes a strong connection to this piece of information, then one possible mechanism for the functional improvements that we have seen with Lycra is both direct deep pressure from contact with the skin and increased internal soft tissue pressure impacting both mechanical stability and pressure receptors. As the deep pressure receptors give more usable information to the Proprioceptive Feedback System, positional limb and body awareness is improved. The person is then able to direct movement and specific muscle activation more precisely. By observation, the little boy with Angelmann's Syndrome, appeared to have very little idea of where the edge of his body ended and the air began. Lycra Bracing from wrists to ankles with double compression through the trunk and across the shoulders, perhaps permitted him to better " feel and place his body in space." Increased light touch from the don of the top and bottom portion of the brace, caused a hypersensitive `fidgety' and `disorganized' response initially. This response was however temporary and changed quickly to a more attentive, interactive and deliberate demeanor within a few minutes. The latency response time for body righting to weight displacement on the therapy ball was reduced almost immediately from a 15-20 second average down to 5-10 seconds. With don of the SPIO, he opened his eyes wider, gave me direct visual regard and smiled. It was as if the Lycra suit "gave him better ownership of his body."

Some of the biomechanical mechanisms are fairly easily seen. Overstretched abdominal muscles can not contract as easily as those which are being held in a less stretched mid-range. Neoprene Cylindrical wraps around arms, legs and trunk exert a direct force against collapse from gravity in weight bearing and upright. Though the direct effect may be more subtle, Lycra also must have some dampening effect on external force vectors which are acting across joints, especially those with multiple degrees of freedom. This permits a slightly longer reaction time and contains overshooting so that the system has the possibility to become increasingly more predictable rather than less predictable.

Increased stability assisted by increased internal pressure on soft tissue structures, also in some cases probably plays a roll in the improved loading of joints which is seen. It is a well known fact that increased intraabdominal pressure provides improved anterior spinal stabilization. Abdominal muscle sets are taught for this reason to be used before and during heavy lifting to support and protect back structures. It makes sense that similar increased soft tissue pressure around shoulder and hip/pelvic girdle areas could be equally helpful in improving joint stabilization and reducing troublesome vector forces. The effect seen in the young girl with spastic diplegia in Louisiana might be an example of this mechanism. An independent walker with forearm crutches, her instable hips snapped and popped with each step. Double thickness SPIO Compression Bracing from the level of the lower ribs to her knees, immediately stopped the popping and clicking sounds and excessive hip lunation movement and improved both gait comfort and efficiency.

Another mechanism which may be contributing to the functional improvement seen, relates to the alteration of external forces. In a conversation with biomechanist, Gad Alon Ph.D., PT, he commented that among all of the force vectors acting to make life difficult for persons with movement control problems, external vector forces are probably causing the biggest problems. By dampening these forces, containing and supporting movement and force generation, persons with neuromotor control problems may be assisted in their ability to redirect force vectors more effectively into supporting surfaces. The more predictable and adaptive base of support may be account for the improved functional movement control which we have observed. Greater predictability of movement control and force generation might allow the person more possibilities to experiment with combined muscle activation in a greater variety of combinations.. This may partially account for the initial and continued more rapid learning curve for movement, stability, control and balance seen in some children with the addition of SPIO Bracing to an already established therapy intervention program. It may also account for the observation that even though function is improved with SPIO Bracing on, improved control generalizes over time to situations without brace wear. The dependency curve appears to lessen with wear instead of increasing.

Back Copyright © 1997 - Nancy Hylton, P.T