If a veteran has a pre-existing condition that was noted in his or her entrance medical exam, then the presumption of soundness does not apply, but if that condition worsens during active service, the presumption of aggravation might apply instead. The presumption of aggravation is found in 38 U.S.C. 1153, which states: “A preexisting injury or disease will be considered to have been aggravated by active military, naval, or air service, where there is an increase in disability during such service, unless there is a specific finding that the increase in disability is due to the natural progress of the disease.”
The presumption of aggravation applies only during active service, so it does not apply if a veteran’s pre-existing condition is aggravated during active duty for training or inactive duty for training. Unlike the presumption of soundness where the burden of proof is on the VA, for the presumption of aggravation to apply, the veteran must submit evidence of an increase in disability. But note, the veteran does not need to prove that a specific incident in service cause the increase – all that is required is evidence that the disability worsened during a period of active military service. Also, the increase in disability needs to be more than a temporary worsening or flare-up, but it is not required that the increase be enough to warrant that the condition be given a higher evaluation on the VA disability rating schedule. The key is that the increase is nontemporary, and is related the underlying condition itself. This requires clear, competent medical evidence. The best type of evidence is documentation of an increase in the disability in the veteran’s service medical records. Another method is to compare the severity of the condition before service with the severity of the condition shortly after service. If the veteran was treated by a private physician for the condition, that will be helpful evidence as well. In addition, lay statements from friends or family who were around the veteran and observed the increase in disability can be useful evidence. But again, medical evidence is the most important evidence in claims involving the aggravation of a pre-existing disability.
If a veteran is able to demonstrate that a pre-existing disability permanently increased in severity during active service, the disability is presumed to have been aggravated by service and no further evidence from the veteran is required. The VA is able to rebut the presumption of aggravation with clear and unmistakable evidence that the increase in disability was due to the natural progression of the disease. This requires a medical conclusion supported by independent medical evidence. While the veteran is not required to submit additional evidence that the condition was aggravated by service, it may be a good idea for the veteran to get an opinion from a non-VA doctor which states that the stress of military service caused the increase in disability, not the natural progression of the disease, in order to make it more difficult for the VA to rebut the presumption.
If the VA is unable to rebut the presumption of aggravation and grants service connection for the disability that increased in severity during service, then the disability rating will be calculated by deducting the severity of the condition as it existed before service from the current level of disability (unless a veteran in totally disabled due to the aggravated condition, in which case no deduction will be made).