In the age of digital medicine, we still have the reflex hammer

It seems that no medical gadget is immune to the wave of digitization pushing healthcare along. From heart rate monitors to thermometers, scales, contact lenses, glasses, blood pressure monitors and inhalers - even the simplest medical devices are going digital. But in this sea of change one tool remains unaffected: the reflex hammer.

Nearly 130 years since its invention by Doctor Auenbrugger in 18th century Vienna, the reflex hammer is still invaluable in diagnosing nervous and muscular disorders. Decades after science has mapped our neuronal pathways, why has the humble reflex hammer hung on?

As NPR recently reported, the reflex hammer remains one of medicine’s most essential tools. A simple knob of rubber on a metal handle is used to assess nerve function by briskly tapping the tendons of major muscles to elicit a reflex. While physicians have experimented with different designs and materials, the basic model we associate with a doctor’s office hasn’t really changed since its invention in the 19th century.

In many cases the reflex hammer remains the best way to determine important components of a diagnosis, like whether a patient's pathology lies in the brain or elsewhere in the body. It can also help prevent wasteful healthcare spending by avoiding unnecessary tests.

“Reflexes tell the story of neurologic diseases of all sorts,” as Dr. Stephen Krieger, a multiple sclerosis expert, tells NPR. A few taps from a reflex hammer can help a neurologist determine whether the patient is suffering from a brain disorder, which results in hyperactive reflexes, or a muscular or nervous condition that usually reduces reflexes.

Properly used, a reflex hammer can help neurologists narrow down some diagnoses without ordering expensive tests. For example, Dr. Andrew Wilner of the Mayo Clinic was diagnosing a patient who had back pain and numbness in their legs. Wilner suspected either Guillain-Barre Syndrome (GBS) - an autoimmune disorder of peripheral nerves - or some kind of injury to the spinal cord.

Using a reflex hammer, Dr. Wilner determined that the patient had brisk knee jerks, pointing to a lesion in the spinal cord that was subsequently found using an imaging study. By listening to the story told by reflexes, the medical team was able to avoid pursuing costly tests involved in a GBS diagnosis.

Digital medical devices are pushing healthcare forward, creating possibilities for new techniques and efficiencies that were unimaginable a decade ago. But as Dr. Krieger points out, “the simple, elegant, inexpensive almost plebeian swing of the reflex hammer has a cost/benefit ratio that I think no advanced technology will ever match.”

The reflex hammer reminds us that when it comes to medical diagnoses, sometimes basic is better.