No, staring at your phone won't give you 'horns,' says physical therapist

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Despite what you may have read, you're probably not going to grow a horn on the back of your skull from staring down at your cellphone, says a physical therapist.

A study published last year in the journal Scientific Reports looked at 1,200 X-rays and found that people aged 18 to 30 were more likely to have larger than usual bone protrusions on the backs of their skulls than people in their 30s, 40s or 50s.

The study's authors — David Shahar and Mark Sayers from Australia's University of the Sunshine Coast — concluded the bumps may be "linked to sustained aberrant postures associated with the emergence and extensive use of hand-held contemporary technologies, such as smartphones and tablets."

That prompted a slew of media outlets — including this program — to declare that young people are growing "horns" because they spend too much time on their phones.

"It's too soon to worry about that," Evan Johnson, an assistant professor and director of physical therapy at New York Presbyterian Och Spine Hospital, told As It Happens host Carol Off.

Reached for comment, Shahar said he and Sayers "have not ever drawn direct links" between the protrusions and cellphone use. Rather, he said, they connect the phenomenon to poor posture that is often associated with mobile technology.

Correlation, but no causation 

Johnson said while the study's findings are important, they have been blown out of proportion. 

"While we all have little bumps on the back of our heads, and it may be that young people's bumps might be a millimetre or two larger than than previous generation's, they're still OK," he said. "Their heads are intact."

These so-called horns are a natural feature in all humans, Johnson, said. The study found that 33 per cent of subjects had a larger than average bump — meaning longer than 10 millimetres. For people under 30, that number jumped to 41 per cent. 

Those larger bumps were more visible in subjects whose necks were bent forward in an abnormal posture, leading the researchers to conclude that when people constantly tilt their heads forward — when looking at a phone, for example — it causes bone growth in the space that connects the back of the skull to the neck.

"So the thought is heads forward, then there's more pulling and that explains a greater bump," Johnson said. 

But linking that to cellphone use, he said, is "a big jump."

With no control group, historical data or information about the subjects' phone use, it's impossible to say with certainly that phones are the culprit.

"There's a correlative link that they make, but there's no causal," Johnson said.

Shahar said his study never claims to find a direct correlation.

"These are postures often associated with the use of mobile technologies (also desk work, etc.) and so we drew some indirect links between these postures, mobile technology use and the presence of aberrant mechanical load to the cervical region of the spine," he said in an emailed statement.

"We are not against these modern technologies (quite the opposite actually), rather we are trying to highlight that sustained poor posture comes at a price."

Scientific backlash 

Still, several people in scientific community have questioned the study's methods and criticized the frenzy of coverage.

Dr. David J. Langer, the chairman of neurosurgery at Lenox Hill Hospital in New York, told the New York Times the study "seems a little bit far fetched."

"You're more likely to get degenerative disc disease or misalignment in your neck than a bone spur growing out of your skull," Langer said. "I haven't seen any of these, and I do a lot of X-rays."

Nivien Speith, a forensic scientist at the of the University of Derby, told Forbes that she's seen "plenty" of these enlarged bones on early Medieval skulls, especially men. 

"It could be genetic, or even just a simple bony outgrowth that has unknown etiology," she said. "Often, they can occur through trauma to the area as well."

While all the focus has been on the bumps, co-author Sayers told the Washington Post they aren't the real problem.

Instead, he called them a "portent of something nasty going on elsewhere, a sign that the head and neck are not in the proper configuration."

On that front, Johnson agrees.

He said it's "unquestionable" that the way we hunch over our phones, laptops and other technology for hours at a time is affecting our posture and our spinal health.

It's all about moderation, Johnson said. Slouching for a few minutes is fine. Hunching over a keyboard for eight hours straight, no so much. 

"It's good to know that there may be this muscular skeletal change, that we do need more studies and more data on that," he said.

"Not so much because it matters that you're growing a horn, so to speak. More because it tells us that hey, the way we're living right now has negative impacts."

Written by Sheena Goodyear. Interview with Evan Johnson produced by Sarah Jackson.