The administration of N-acetyl-cysteine (an anti-oxidant) for seven days along with observation will result in improved hearing and balance function in individuals who demonstrate these disorders after blast exposure when compared to a placebo medicine and observation at the seven day time point.

5.0 RESEARCH PLAN: The goal of this study is to examine the use of one anti-oxidant, N acetylcysteine (NAC), in individuals who suffer blast injury and demonstrate early sequela of mTBI.

Recent changes in war fighting and operational situations have changed the injury patterns that our troops face in all aspects of military operations. Mild traumatic brain injury (mTBI) is among the most common injuries seen in the current theater of operations. While other injury patterns have shown a decrease over the last twelve months, mTBI from blast exposure has continued to be seen at increasing levels. This may be due in part to the fact that research has shown the individuals may suffer mTBI secondary to blast injury from one significant exposure or from repeated low level exposure which is more common as individuals rotate back to the theatre of operations for second, third, and even forth tours of duty. The sequela of mTBI include balance disorders, hearing loss, and cognitive dysfunction. These disorders can present immediately after the injury or several weeks after the injury but tests of function can detect injury shortly after the injury. Evidence exists in laboratory work and in human studies that anti-oxidant medicine can reduce/eliminate the sequela of mTBI if administered within 8-24 hours of injury.

5.1 OBJECTIVES: A population and single-subject design, double blinded, placebo controlled study comparing the effectiveness of the observation and administration of the anti-oxidant NAC to placebo in individuals suffering the sequela of mTBI after a single or multiple blast exposures.

5.2 HYPOTHESIS: The administration of NAC for seven days along with observation will result in improved hearing and balance function in individuals who demonstrate these disorders after blast exposure when compared to a placebo medicine and observation at the seven day time point

5.3 SPECIFIC AIMS:

1. To determine the frequency of hearing loss and balance disorders in those exposed to blast injury that have non-emergent or non-urgent medical or surgical disorders and display a pattern of injury consistent with mTBI.
2. To determine the effectiveness of one week of anti-oxidant, N-acetylcysteine combined with observation, in the reduction of hearing loss and balance disorders one week after injury as compared to placebo medication and observation.
3. To determine the effectiveness of one week of anti-oxidant, N-acetylcysteine combined with observation, in the reduction of hearing loss and balance disorders six months after injury as compared to one week of placebo medication and observation.

Inclusion Criteria:

1. Be active duty United States Service member
2. Be between the ages of 18 and 50 years
3. Present to TQ Surgical within 24 hours of blast exposure.
4. Have complains consistent with possible TBI including hearing loss, dizziness, lightheadedness, cognitive difficulties, and/or had loss of consciousness.
5. Are not expressly excluded by the criteria listed below.

Exclusion Criteria:

1. Require urgent or emergent surgical procedures.
2. Will require medical evacuation to any level III or higher facility (other then to a level III for a CT scan only).
3. Has evidence of an open head wound.
4. Pregnant Females
5. The use, within the last seven days, of a nutritional supplement containing an anti-oxidant.