Low body weights, sometimes severely so, are common in patients with cerebral palsy (CP). There may be several causes of those low weights, including feeding difficulties that can make it difficult for people with CP to efficiently chew, swallow and digest food properly, which can lead to malnourishment.

Another popular belief is that spasticity and high muscle tone burn large numbers of calories over extended periods of time, thus leading to weight loss or the inability to put on weight. But is that theory true?

A study of 56 children with CP followed their growth after they underwent Selective Dorsal Rhizotomy (SDR), a surgical procedure meant to cut some sensory nerve fibers believed to cause spasticity. Results were published in BMC Neurology in 2010.

Despite the common belief that spasticity is a major culprit in low body weights for people with CP, researchers noted, “Energy expenditure in spastic CP is not well understood. Adaptation to low food intake, altered regulation of basal metabolism, reduced lean body mass, and decreased mobility are suggested to counterbalance the energy costs of spasticity. On the other hand, increased weight gain velocity after reduction of muscle tone by means of intrathecal baclofen (ITB) is reported in the literature.”

Weight Gain Following Surgeries

The children in the study ranged from underweight to overweight prior to undergoing SDR. Afterward, researchers noted weight gains in general, which was helpful to children who’d been seriously underweight, but was less helpful to children who either became overweight from the weight gain, or who’d been overweight to begin with and became even heavier after the procedures.

Researchers also noted that they couldn’t extrapolate from the children’s growth charts after surgery “since many of the included children had different degrees of chronic malnutrition.”

To read the study, go to biomedcentral.com/1471-2377/10/57).