The Role Of Spasticity In Body Composition And Energy Expenditure After Spinal Cord Injury

Abstract

Deterioration in body composition after spinal cord injury (SCI) is well documented. Individuals with SCI have a reduction in fat free mass (FFM) and increase fat mass (FM). Factors that might attenuate such deterioration are worth investigating. We have recently shown that spasticity, increased muscle tone, could defend against muscle atrophy. However, the effect of spasticity on whole body composition and energy expenditure is not well documented. PURPOSE: To determine the effect of spasticity on body composition and energy expenditure in chronic individuals with SCI. METHODS: Ten individuals with chronic SCI (33 ± 7 yrs old; 25 ± 4 Kg/m2; C6-T11; American Spinal Injury Association A and B) were recruited from the outpatient clinics of the University of Michigan. After being admitted to the General Clinical Research Center, the ten participants underwent assessment of their body composition using Dual Energy X-ray Absorptiometry to measure their FFM and FM. Spasticity of the hip, knee and ankle flexors and extensors was measured using modified Ashworth Scale at 2, 5 and 8.00 pm. The average of the three time points was recorded. After overnight fasting, resting metabolic rate (RMR) using indirect calorimetry unit was assessed. RESULTS: The RMR was 1256 ± 231 Kcal/day. Their respiratory exchange ratio was 0.76 ± 0.05. FFM and FM were 64 ± 6 and 36 ± 6 %, respectively. Increased knee extensor spasticity was associated with greater total %FFM (r=0.64; P = 0.048). Additionally, knee extensor spasticity was associated with lower %FM (r = −0.66; P = 0.03). Increased FFM (Kg) was associated with higher RMR (r= 0.89; P= 0.0001). However, increasing spasticity did not appear related to RMR. CONCLUSIONS: Spasticity may help to defend deterioration in body composition after SCI and may indirectly influence RMR by maintaining FFM. Supported by STARS foundation, NIDRR (H133P030004) and GCRC (NIH-M01- RR000042) to ASG.