Programs that use the resources of law enforcement and the media to alert the public when a senior or vulnerable adult (particularly individuals with Alzheimer's Disease, another form of dementia or other mental disabilities) is missing. Silver Alerts uses a wide variety of media outlets including radio stations, television stations and cable television to broadcast information about missing persons. Variable message signs on roadways may also be used to alert motorists to be on the lookout for the missing individual; and reverse 911 or other emergency notification systems can be employed to alert residents of a neighborhood when a missing person is believed to be on foot. Activation criteria for Silver Alerts vary from state to state, but in general, the decision to issue an alert is made by the law enforcement agency investigating the missing person report.