For which condition is 38 CFR 3.318 applicable?

38 CFR 3.318 specifically pertains to service connection for Amyotrophic Lateral Sclerosis (ALS), acknowledging the unique circumstances surrounding this condition. Under this regulation, veterans who have served at least 90 days of active service are eligible for a presumption of service connection for ALS. The regulation recognizes that there is a sufficient basis for presuming a link between military service and the development of ALS, streamlining the process for those affected by this debilitating disease.

This provision is significant because ALS is a progressive neurodegenerative disease that profoundly affects motor neuron function, leading to severe physical limitations. The presumption eliminates the need for extensive evidence proving service-related causation, allowing veterans access to benefits more easily.

The other options, while related to distinct aspects of veterans' benefits and conditions, do not specifically align with the stipulations set forth in 38 CFR 3.318 and therefore are not applicable to this particular regulation. Chronic diseases and diseases due to ionizing radiation exposure have their own respective regulatory frameworks and criteria, while secondary service connection involves conditions that are a result of a service-connected disability rather than a primary condition like ALS.