VNG Balance Testing in St. Louis: When Neuropathy Is Not the Only Reason You Are Unsteady

What Happens During a VNG Test?

Testing is non-invasive. There are no needles and no injections. You sit for most of it. Sensors are placed near the eyes to record movement while you look at targets and while your position is changed.

Some position changes can bring on brief dizziness. That is part of what is being measured, not a sign something went wrong. The feeling usually settles quickly. Tell the person testing you if you have neck or back limits, so the positions can be adjusted. If position changes tend to leave you unsteady, it is wise to have someone drive you home.

The Metabolic Dose–Response: Why the Ear Fails Alongside the Nerve

This is the part that makes vestibular testing a neuropathy question, not an ear question.

Researchers examined vestibular function in the National Health and Nutrition Examination Survey. They did not simply find that people with diabetes had more inner-ear dysfunction than people without. They found that it tracked with the metabolic state. It was more common with longer disease, more common with higher hemoglobin A1c, and more common alongside the other diabetic complications. The authors described the pattern as suggestive of a dose–response relationship between the severity of the metabolic disease and damage to the vestibular system.

The same analysis went further. Vestibular dysfunction raised the odds of falling more than twofold in people with diabetes. The odds ratio was 2.3 (95 percent confidence interval 1.1 to 5.1). And that was after adjusting for peripheral neuropathy and retinopathy. Then vestibular dysfunction, peripheral neuropathy and retinopathy were all entered together. The link between diabetes itself and falling disappeared into those three complications.

That is the terrain argument, stated in survey data. The inner ear is not a separate organ that happens to fail at the same time as your feet. It is the same small-vessel, small-fiber, metabolically-driven process showing up in a different tissue. And it adds to your fall risk independently of what your feet are doing.

It is also why treating the terrain is not an add-on to balance care. It is the part of balance care with the most leverage.

Quantifying Fall Risk Takes More Than One Test

Standing upright is a system with backups: inner ear, position sense from the feet and legs, and vision, checked against each other all the time. Any one part can weaken a long way while the other two carry the load. That is why people with large deficits walk normally in a bright, familiar room and go down in a dark hallway.

So the number that matters is not whether a deficit exists. It is how much reserve is left. That takes measuring more than one system:

• VNG — the inner ear and its central connections. It shows whether a loss is peripheral and can be rehabbed, or central and something else.
• Kinetisense [Gait Analysis for Fall Analysis] — markerless motion capture of posture, weight shift, sit-to-stand and gait. It shows the end result after every system has made up for the others.
• Cognivue [Cognitive and Memory Testing] — attention and processing speed. These decide whether a stumble gets caught or ends in a fall.
• Small fiber and autonomic testing — feeling from the sole, and the blood pressure response to standing. A silent orthostatic drop (blood pressure falling when you stand) is its own way to fall.
• Ankle–brachial index and vascular flow — because numb, cold feet are not always a nerve problem, and the treatment is entirely different.
• EMG and nerve conduction studies — whether weakness comes from a peripheral nerve, a nerve root or muscle. Only electrodiagnostic testing tells them apart.

A systematic review of diagnostic balance tests reached the same conclusion from the research side. A brief test is reasonable for screening, but a battery is needed for a comprehensive assessment. One test finds one deficit. It tells you nothing about the margin behind it. A full assessment instead produces a set of numbers that can be tracked: a risk-of-fall percentage, a mobility index, cadence, sway and gait velocity. Each is also compared against normal values.

What Losing Your Footing Actually Costs

For a neuropathy patient, the loop feeds itself through metabolism. That makes it different from an ordinary fall risk. Unsteadiness cuts down walking. Less walking costs muscle, and muscle is where most glucose is cleared. Poorer glucose clearing worsens the small-vessel and small-fiber damage already underway. That damage weakens feeling and inner-ear function further, and the unsteadiness deepens. The fall does not start the cycle. It speeds up one that is already turning.

What gets lost along the way is not recorded anywhere. Driving. Stairs. Showering without help. Going out after dark. Staying in your own home. People give these up one at a time, quietly. They usually tell nobody until something breaks.

There is a wider cost too. Neuropathy is common and under-diagnosed. Its balance effects arrive so quietly that they are often recorded for the first time in an emergency room. Then come the fracture, the hospital stay, the loss of independent living, and the family member who leaves work. That is costly in every way that matters. Nearly all of it flows from a metabolic process that could have been measured years earlier. Balance testing is not an extra in neuropathy care. It is how you find out how much time is left to change the outcome.