Certain sounds could relieve back stiffness
Sarah Berry | Fairfax Media | Sep 11 2017
If you were to describe the sensation of back stiffness you might use words like creaking, cracking and popping.
New research reveals this innate tendency to connect sound (or sight or smell) with sensation could change the way experts understand and treat lower back pain, a problem that affects 80 per cent of us and is the world's biggest contributor to disability.
Back pain experts already understood that physical pain goes hand-in-hand with perception; if we feel safe our body relaxes, softening our perception of pain whereas if our body senses danger it protects itself by amplifying our perception of pain.
For the paper, published in Nature journal Scientific Reports, Dr Tasha Stanton wanted to explore this concept further to see whether engaging our sense of sound could influence these perceptions.
"We thought that adding sounds that either increased or decreased the need for protection would impact people's protective responses for their back," said Stanton, a senior research fellow from The University of South Australia's School of Health Sciences. "And, indeed, this is what we found."
When they applied pressure to the spines of participants while playing a creaky door noise, people were more protective of their backs and believed the pressure being applied was greater than it was. When they applied pressure while playing a gentle whooshing sound or a noise that became less creaky over time, participants were less protective and believed the pressure being applied was less than it was.
"Critically, these changes in perception relate very well to feelings of stiffness," Stanton explained. "The more you overestimate force, the more stiff you feel and vice versa. In contrast, we found that actual objective measures of back stiffness [mechanical stiffness] do not relate at all to how stiff the back feels."
It is this mismatch between mechanical problem and pain perception that has researchers intrigued and has significant implications for the way pain is treated.