Bruce Willis is only 68 years old. His cognitive decline you mentioned is somewhat bizarre for such a young age. The question is why? Many people believe it was the 'clot shot'. This could very well be. Others think it is 'something' else. This could very well be... I don't know if this is true, but the frequent use of cocaine could be a factor. I don't know if Willis was in to that 'scene', but the era he became famous was when cocaine was flowing openly everywhere in Hollywood. The long term effect is cognitive decline. Jack Nicholson is another case similar to Bruce Willis.