Jabbing a steel needle into your flesh is not ever going to be fun, per se, but scientists have found a way to make it at least hurt a lot less. The trick is actually fooling your nerve cells with a small device that applies pressure and vibration. Here's how it works.
Popular Science reports on a study presented at this week's meeting of the American Society of Anesthesiologists. The 21 volunteers in the study were poked in the shoulder while various amounts of heat, cold, pressure, and vibration were applied. (One caveat, they were jabbed with a plastic needle that doesn't puncture the skin but causes needle-like pain because, well, ethical research standards.) The researchers found that a certain amount of pressure and vibration applied for 20 seconds before the jabbing was the most effective. Temperature didn't seem to make much of a difference.
How does this fool the brain? Well, the gate control theory of pain says that pain signals originating from the broken skin must pass through "nerve gates" in the spinal cord on its way to the brain. But these gates can be blocked by other physical sensations, like pressure or vibrations. This also explains why applying pressure to an cut makes it a little less painful.
Dentists can already use some form of a vibrating needle, though this new study suggests pressure and vibration before the injection may be of more benefit. And, to take completely different tacks, there are also scientists developing sugar microneedles and swallowable injections. The future of shots could be a lot less painful. [ASA via Popular Science]
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