6 Times Your Brain Acts Nutty (Déjà Vu, Anyone?) And When To Worry

If you've ever been unable to get a song out of your head, written down a common word that suddenly looks misspelled, or walked into a new building and felt as if you'd been there before, it's all in your head. Literally. Most of these tics are completely harmless, although a couple may be a sign it's time to seek help. Here's what experts say about common brain quirks.
 
1. It's a small world after all…over and over.
If your last trip to Disneyland left you with the "small world" song playing through your head for the rest of the day, you've experienced an earworm. "It's annoying but not harmful," says Allen Towfigh, medical director at New York Neurology and Sleep Medicine. "The loop of the song in your head is usually as long as your short-term memory; it's a loop that continues to fire." Towfigh notes that no research currently exists on earworms but says not to worry about it, as it happens to 98% of people.

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2. That word doesn't look right.

You're writing away on your computer when you notice a word that doesn't look right. It's one you see every day, so what gives? "When a common, simple word suddenly looks odd, we call that wordnesia," says Towfigh. "There's no neurological basis for it. It's simply anecdotal and could be an element of fatigue." Wordnesia is not a concern unless you actually can't recognize the word, in which case there might be actual trouble brewing, like stroke.
 
3. Didn't we already have this conversation?
Déjà vu, the feeling you've seen or felt something or been somewhere before, may be due to a slight difference in your brain's processing speeds, says Towfigh. "You listen and hear with two eyes and two ears. One theory behind déjà vu is that one input occurs a millisecond before the other ear or eye and makes it feel as if it's already occurred." In addition, your brain keeps a constant record of your experiences and can "scan" through its files and make an accidental pairing or connection to a prior similar experience. In rare cases such a feeling can also occur before a seizure, but is otherwise harmless.

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4. Music becomes color, names have flavor.
For people with synesthesia, the stimulation of one sense triggers an involuntary response from another sense. A person may "taste" names or see letters and numbers in color. Many artists and musically inclined people are synesthetes, including Mary J. Blige, Bob Dylan, and Pharrell Williams. "Synesthesia does not seem to be indicative of an underlying disorder," says Gayani DeSilva, a psychiatrist with St. Joseph Hospital in Orange, CA. "I suspect that as we learn more about sensory integration disorders, we will learn more about why some people perceive sensory input in different ways."
 
5. Who are you? Where am I?

Suddenly forgetting your own name and not recognizing people around you could be symptoms of transient global amnesia. During TGA your recall of recent events disappears, and you can't remember where you are or what's happening in the moment. It can be a sign of a seizure or a stroke, says Towfigh. "If you have a small seizure in the hippocampus, the part of the brain responsible for memory, your memory returns as blood flow is restored." It may happen once and never again but should always be checked out.  

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6. I don't remember this place.
In jamais vu, which is basically the opposite of déjà vu, a familiar setting suddenly seems unrecognizable. Or a person you know well is now unfamiliar. "This feeling often occurs before an epileptic seizure," says Towfigh. "It may be your brain's inability to match with its stored records." Other theories suggest jamais vu can be induced by repeatedly writing or saying a word out loud. After a while the word seems odd and unfamiliar, which researchers blame on "brain fatigue."