Clinical Bottom Line
“How should I apply this information?”
This study provides information about the relationship between muscle volume and spasticity in children with diplegic cerebral palsy (CP) that has not been previously examined, using objective and reliable measurement tools. It offers therapists an alternate measure (isokinetic dynamometry) to the less reliable Modified Ashworth Scale for examining spasticity.
As the results of this study indicated significant, positive correlations in reflexive knee extensor activity with the volume of the muscle, this leads one to reconsider the traditional decision to decrease spasticity. Can spasticity in some cases actually be a “good thing?” For instance, the authors report that recently researchers have suggested that increased muscle volume in a spastic muscle may in fact provide metabolic benefits. In addition, if a muscle has an increased volume, might this indicate less disuse atrophy and possibly muscle strength (or potential for strengthening)? If this is the case, a closer examination of efforts to decrease spasticity is warranted, encouraging therapists to “think outside the box.”
“What should I be mindful about when applying this information?”
As the authors stated, the clinical relevance of this study is unknown. Does increased muscle volume lead to improved function? Does the amount of spasticity have a relationship to function? Does muscle volume or the level of spasticity have a relationship to strength?
Several conditions in the testing protocol also suggest caution in applying this information clinically. For instance, in daily movement (transitions, gait, etc), how often is the arc of 25° to 90° of knee flexion used in isolation and in what body positions? The degree of spasticity in children with CP is often related to position, movement, and effort. A child sitting in a fully supported position does not compare to an active child dealing with spasticity when more of the body is in motion or the task is more difficult. In addition, is the constant rate of 180° per second typical for a child with diplegic CP in everyday movement? Before we begin to consider changes in delivery of services and treatment of patients, we must consider these questions and be cautioned to not apply the results to client function too quickly.
Deborah Nervick, DPT, DHS, PCS
Franklin Pierce University
Concord, New Hampshire
Jennifer Parent-Nichols, DPT
Milford, New Hampshire