“Amino acids and fatigue after brain injury.”
Abstract:
Traumatic brain injury (TBI) is associated with many chronic deficiencies and disabilities. These dysfunctions are both psychological and physiological in nature. Psychological alterations include a diminished sense of well-being, depression, chronic fatigue, and anxiety. Plasma amino acids are important precursors for brain neurotransmitters that may affect these states. Studies have shown disturbances in the plasma essential amino acids (EAA) pattern in TBI patients, and we hypothesize that nutritional supplementation of EAA may reverse these disturbances in TBI patients. Specifically, we hypothesize that EAA supplementation will reduce fatigue in TBI patients.
In this study, we will first characterize the amino acid patterns in TBI patients and compare this to healthy controls. Further, we will investigate the response to an EAA supplement in these clients. This supplement has previously been shown to effectively increase plasma EAA concentrations and stimulate muscle protein synthesis in healthy controls. Based on the observed response in individuals with TBI, the supplement may be adjusted. We will thereafter provide it during an exhaustive sub-maximal exercise test. We hypothesize that EAA supplementation will increase the time to exhaustion when compared to a placebo supplement given instead.
Specific Aims:
The specific aims of this study are as follow:
- Compare the plasma concentrations of individual amino acids, and relations between them, in traumatic brain injury (TBI) patients and healthy controls
- Compare the response of plasma concentrations of individual amino acids to an essential amino acid (EAA) drink during rest in TBI patients and healthy controls
- Determine the test-retest variability of a sub-maximal exercise test to exhaustion in TBI patients
- Determine the effect of EAA supplementation (designed as a result of specific aims 1 and 2) during sub-maximal exercise on time to exhaustion in TBI patients.
