Types of Service Connection
Condition incurred or aggravated during military service
Direct Service Connection
Condition incurred or aggravated during military service
Secondary Service Connection
Condition caused or aggravated by already service-connected condition
Presumptive
Conditions presumed service-connected (e.g., Agent Orange, Gulf War, PACT Act burn pits)
Aggravation
Pre-existing condition worsened beyond natural progression during service