In a groundbreaking feat of science, a pair of psychologists at the University of Melbourne have proved that there are no senses beyond the normal five. (Wow.) This probably means that this kind of thing is fake, too:
Instead, the sensation you may be experiencing all comes down to not being able to identify what, specifically, has changed in the visual field you're processing. The authors write:
In particular, it is clear that to some extent we are also aware of the global properties of the scene, such as the mean luminance or the distribution of spatial frequencies. It follows that we may be able to detect a change to a visual scene by detecting a change to one or more of these global properties. However, detecting a change to global property may not supply us with enough information to accurately identify or localise which object in the scene has been changed. Thus, it may be possible to reliably detect the occurrence of changes without being able to identify or localise what has changed. Previous attempts to show that this can occur with natural images have produced mixed results. Here we use a novel analysis technique to provide additional evidence that changes can be detected in natural images without also being identified or localised. It is likely that this occurs by the observers monitoring the global properties of the scene.
In a write-up of their study at The Conversation, the authors conclude: "Our study therefore shows that people can indeed detect changes that they cannot identify, but debunks the claim that this is evidence for a sixth sense."