Measuring Muscle Tone May Help Assess Nutritional Needs of Children With CP, Study Says

Measuring both body composition and muscle tone in children and adolescents with cerebral palsy (CP) may help to evaluate their nutritional status, a new study suggests.

The study, “The Relationship between Body Composition and Muscle Tone in Children with Cerebral Palsy: A Case-Control Study,” was published in the journal Nutrients.

Brain injury associated with CP often causes inappropriate muscle activation and an increase in muscle tone that leads to stiffness and tightness. Higher muscle tone is believed to require more energy during movement. 

“These changes directly affect general health, mobility, and independence in everyday life, increasing the level of disability in children with CP,” the researchers wrote.

Increased muscle tone also leads to more difficulty in food intake and swallowing, resulting in nutritional deficits that can exacerbate the development of these children.

Previous studies have shown that the amount of energy obtained through food is sometimes insufficient to meet the energy needs of children with CP. As such, body composition analysis is an important tool to estimate such needs. 

A method known as bioelectrical impedance analysis (BIA) is a common tool to assess the nutritional status of children with cerebral palsy. BIA is a noninvasive technique that sends a harmless electric current through the body. Different types of tissue offer different resistance to the movement of the current, thereby allowing scientists a way to measure body components.

The method gives measurements of the amount of fat mass and other components (fat-free mass) present in the body. Muscle mass and total body water are measured. BIA is also able to measure the metabolically active component of a person’s fat-free mass, defined as the body cell mass. Importantly, measurements by BIA can be used to assess a child’s nutritional status.

In the study, researchers at the University of Rzeszow assessed the relationship between body composition using BIA and muscle tone using the Ashworth scale (higher scores indicate more muscle tone).

The study enrolled 118 children and adolescents (ages 4–18, 76 boys) with CP who had different levels of motor skills, as determined by the Gross Motor Function Classification System (GMFCS).

Most children were defined as GMFCS level II (47.5%) and as having spastic cerebral palsy (79.7%). A group of healthy individuals, matched for age and sex, was included as a control.

Results showed that children with CP had significantly lower fat-free mass, muscle mass, body cell mass, and total body water than healthy children. 

In addition, the body cell mass index was significantly lower in boys with CP. The same tendency was observed in girls with CP, although it did not reach statistical significance. 

“These results provide evidence that children with CP have lower energy reserves reflected by lower body composition parameters, which may result in a potentially higher risk of undernutrition and faster dynamics of changes in the body component due to existing malnutrition,” the researchers wrote. 

Children with CP who had higher scores in the Ashworth scale, or higher muscle tone, were found to have significantly lower values of fat mass, fat-free mass, muscle mass, body cell mass, and total body water.

“These findings are linked with the increased caloric intake needs proportional to the increased muscle tone,” the researchers wrote, and this higher energy need “results in a reduction of all the components of body composition.” 

In addition, children with more impaired motor skills, corresponding to GMFCS level III-IV, had significantly lower values of fat-free mass, muscle mass, body cell mass, body cell mass index, and total body water, compared with those classified as level I-II.

Overall, these findings “showed lower parameters of body composition in children with CP compared to healthy children, and a decrease in the parameters coinciding with higher muscle tone in the study group.” 

These results suggest that it is “necessary to measure and cure muscle tone while assessing the nutritional status of children with CP.”