BlackBerry Thumb: Real Illness or Just Dumb?

Jan. 26, 2005 -- Do your thumbs hurt? If you're sending lots of text messages, you may have the trendiest new malady: "BlackBerry thumb."

Yes, you can peck out text messages with any finger. But users of popular wireless devices such as the BlackBerry type much faster by pecking out messages with their thumbs. Many people soon learn to type 40 words a minute.

Whatever your thumb-typing speed, lots of messages mean lots of repetitive thumb motions. And that could mean trouble, says Alan Hedge, PhD, director of the human factors and ergonomics research group at Cornell University in Ithaca, N.Y.

"The thumb is not a very dexterous part of the hand," Hedge tells WebMD. "It is really designed as a stabilizer for pinch gripping with a finger. That is why you only have two of them, not eight. It is the fingers that have dexterity, not the thumb."

The full-size keyboard was designed with this in mind. One uses one's dexterous fingers for lightning strikes on the letter keys. One reserves one's relatively clumsy thumbs for the humble task of striking the spacebar.

"When you switch that around, you put a lot of strain on the thumb," Hedge says. "So if you persist in typing a lot of information with your thumbs, you risk injury."

Hand surgeon Prosper Benhaim, MD, associate professor of orthopaedic and plastic surgery at UCLA, agrees that too much thumbing could be injurious.

"Anything that causes repeat motion can predispose someone to injuries of various sorts, whether it is tendinitis or aggravating underlying arthritis," Benhaim tells WebMD. "These things can be made worse or even initiated by overuse. But thumb typing is very repetitive, and the keys are so small it makes it difficult to navigate around easily. Because it is so small, people are likely to press harder vs. a larger keyboard. So the thumb on the BlackBerry does more than you would do with your fingers on a keyboard.'