Objectives: 1) to determine whether patients with recent TBI entering a rehabilitation facility are dehydrated, malnourished, and/or have an increased resting metabolic rate; 2) to determine whether resting metabolic rate is associated with severity of TBI; 3)to determine the duration of metabolic changes seen in BI patients admitted to a rehabilitation facility. Patient Population: Patients admitted to the inpatient TBI unit at SRH for treatment of head trauma. Methods: Patients had their caloric expenditure measured three times: once upon admission, and two times during their first week of stay. Resting energy expenditure data will be obtained using a portable metabolic unit (Cosmed, K4b2, Rome, Italy). Results: Data was collected on 21 subjects. The test/retest reliability of the device was found to be poor. IRB approval has been obtained to conduct the study with a specially calibrated filter for the portable metabolic unit, which will improve test/retest reliability.