Balance and Fall-Risk Testing in St. Louis

Standing upright is not one system. It is three, cross-checking each other several times a second: the balance organs of the inner ear, the position sense coming up from your feet and legs, and vision. The brain compares the three. When they agree, you do not think about it. When one drifts and the other two disagree with it, you feel unsteady — and you compensate, usually without knowing you are doing it.

Videonystagmography — VNG — measures the first of those three directly. Small sensors placed around the eyes record eye movement while you follow targets, change head position, and sit in darkness. Eye movement is used because the inner ear is wired straight to the muscles that move the eyes; that reflex is what holds an image steady while your head moves. Recording the eyes is the most practical way to read an organ buried in bone.

What comes back is not a yes or no. It is a description of which side is weaker, whether the loss is peripheral or central, and how much of your steadiness is currently being carried by vision and by your feet — the two systems that compensate when the inner ear stops pulling its weight.

Because the patients most likely to have two of the three systems failing at once are the patients we see every day.

Peripheral neuropathy takes away position sense from the feet. Cervical radiculopathy and spinal stenosis change how the legs are recruited. Chronic pain narrows how much people move, and movement is what maintains balance. Several drug classes used for pain and for blood pressure blunt the reflexes that catch you. Diabetes damages nerve, vessel, and — as the data below show — the inner ear as well.

A patient with numb feet has already spent down their reserve. They are standing on vision and the inner ear. If the inner ear is also impaired and nobody has checked, the first sign is the fall.

This is the part that changes management, so it is worth stating precisely.

Using the National Health and Nutrition Examination Survey, Agrawal and colleagues found that 35.4 percent of US adults aged 40 and older — about 69 million people — had measurable vestibular dysfunction. Odds were 70 percent higher in people with diabetes. Among those whose vestibular dysfunction was clinically symptomatic, meaning they reported dizziness, the odds of falling rose twelvefold. That is a survey of 5,086 US adults aged 40 and older, and the measure was a standing-balance test, not a full vestibular battery.

A second analysis of the same survey went further and asked the question that matters here: in a person with diabetes, is the inner-ear problem simply the neuropathy showing up again, or is it its own thing? Vestibular dysfunction independently raised the odds of falling more than twofold — odds ratio 2.3, 95 percent confidence interval 1.1 to 5.1 — after adjusting for peripheral neuropathy and retinopathy. More striking still, once vestibular dysfunction, peripheral neuropathy, and retinopathy were all entered into the model together, the association between diabetes itself and falling disappeared. The three complications accounted for it.

Read that plainly: in a diabetic patient, testing the feet and stopping there measures part of the risk and reports it as the whole. Peripheral neuropathy is independently associated with falls in its own right, which a 2024 case-cohort study in the Journal of the Peripheral Nervous System also found — though that study followed only 31 people, and its effect size should be read as a direction, not a number to quote.

No one of these is a fall-risk score. Together they say which system is failing, by how much, and whether anything about it is treatable.

VNG — the inner ear and its central connections. Separates a peripheral vestibular loss, which often responds to rehabilitation, from a central pattern that means something else is going on.

Cognivue [Cognitive and Memory Testing] — computerized cognitive assessment. Attention and processing speed are what let you react to a trip before you are on the floor. Cognitive testing is a named part of a standard fall-risk assessment for exactly that reason.

Kinetisense [Gait Analysis for Fall Analysis] — markerless motion capture that records how you actually move: gait, posture, weight shift, and how you rise from a chair. It measures the output of the whole system, after all the compensating is done.

Small fiber and autonomic testing — the small nerve fibers that carry sensation from the sole, and the autonomic fibers that hold your blood pressure up when you stand. Blood pressure that drops on standing is a fall mechanism in its own right, and it is silent.

Ankle–brachial index and peripheral vascular flow — because numb, cold, painful feet are not always nerve. Circulation and nerve produce overlapping symptoms and entirely different treatment.

EMG and nerve conduction studies — where the weakness is coming from. A foot that will not clear the ground can be a peripheral nerve, a nerve root at the spine, or muscle. Electrodiagnostic testing tells them apart, and the answer changes what is worth treating.

Every one of the systems above can fail quietly, and every one of them can be compensated for — until another one fails. That is the trap. Someone can lose most of one inner ear and walk normally in a bright, familiar room, then go down in a dark hallway or on a patterned carpet where vision stops helping.

A single test finds a single deficit and tells you nothing about the reserve behind it. Measuring several systems tells you how many of them are still working, which is the thing that actually predicts whether the next stumble ends on the floor. The balance-testing literature reaches the same conclusion from the other direction: a systematic review of diagnostic balance tests concluded that a brief test is reasonable for screening, but that a battery is needed for a comprehensive assessment.

It also produces something a score cannot: a list of which specific deficits are treatable. Vestibular loss can be rehabilitated. Orthostatic drops can be managed. A contributing medication can be reconsidered. A compressed nerve root can be treated. Knowing which of those is in play is the entire point.

You will be seated for the VNG portion, wearing a light head-mounted unit with sensors placed around the eyes. You will be asked to follow a moving target with your eyes, and your head and body will be moved into several positions. Part of the recording is done with your eyes open in darkness, because that is when the inner ear has to work without vision covering for it.

Some of the positional portions can provoke brief dizziness. That is not a side effect — provoking and recording it is how the test localizes the problem. It usually settles within minutes of sitting up. Bring someone to drive you if you are prone to motion sickness or if dizziness is your main symptom.

The other components are painless. Cognivue [Cognitive and Memory Testing] is done at a screen. Kinetisense [Gait Analysis for Fall Analysis] records you walking and standing. Vascular and autonomic testing use cuffs and surface electrodes. Nerve conduction studies use brief electrical pulses that feel like a tap or a snap; needle EMG, when it is needed, involves a fine solid needle and is described by most patients as a deep ache rather than a sharp pain.

Tell us beforehand what you take. Several medications — including sedatives, some antihistamines, and anything that suppresses dizziness — will change the recording, and we will tell you which to hold and for how long.

The output is a map of which systems are contributing, and in what proportion. That drives four decisions.

What is rehabilitable — a peripheral vestibular loss is often trainable, and the exercises are specific to which side and which canal. What is medical — an orthostatic blood pressure drop, a B12 or vitamin D deficiency, glucose that is doing damage below the threshold that gets called diabetes. What is structural — a nerve root or a stenosis that electrodiagnostic testing has localized. And what is environmental — because if you are running on vision, lighting, floor surface, and footwear stop being lifestyle advice and become part of the treatment.

We also repeat the measurement. A single reading is a snapshot; the useful information is the direction of travel, and whether what we did about it moved anything.

The output is quantified and it is repeatable, which is what makes serial testing worth doing. A gait assessment returns a risk-of-fall percentage, a mobility index, cadence, sway and gait velocity, each of it also expressed against normative values for comparison. Read once it is a snapshot. Read across visits it shows whether the direction of travel has changed — and whether what we did about it moved anything.

Nerve, vessel, inner ear, and brain are not four unrelated organs that happen to fail together in the same person. They share a supply, and they share a substrate. Small vessels and small nerve fibers are the first tissue to register a metabolic problem and the last to be looked at, which is why a person can be told their labs are fine while three balance systems are already degrading.

The survey data make this concrete rather than theoretical. Vestibular dysfunction in the National Health and Nutrition Examination Survey was not simply present or absent in people with diabetes — it tracked with how long they had been diabetic and with their hemoglobin A1c, a pattern the authors described as suggestive of a dose–response relationship between the severity of the metabolic disease and the damage to the inner ear. The ear was reading the metabolic state, the same way the feet were.

That is why this assessment does not stop at the balance organs. Glucose handling, insulin resistance, B12 and vitamin D status, blood pressure regulation, muscle mass, and vascular flow are part of the workup, because they are the upstream drivers of what the balance tests are measuring downstream. Insulin resistance precedes a diabetes diagnosis by years and a routine glucose test will miss it. Metformin depletes B12. Losing muscle removes both the strength to catch yourself and a source of the signaling molecules that regulate inflammation.

Treating the readout without treating the terrain buys a little time. Treating the terrain is what changes the direction of travel.

A fall-risk assessment sounds like a narrow, technical thing. It is not, and it is worth being plain about why we invest this much in it.

Falling is rarely a single event. It is the hinge in a sequence: an injury, then a fear of falling, then less walking, then less muscle, worse glucose control, worse circulation, worse nerve function, worse balance — and a higher chance of the next fall. Each turn of that loop is also a loss of something a person actually cares about. Driving. Stairs. Showering without help. Going out after dark. Living in their own home. People stop doing these one at a time, usually without telling anyone, and the medical system tends not to notice until an ambulance is involved.

The cost does not stay with the individual either. It lands on a spouse who becomes a caregiver, on adult children who reorganize their working lives, and on a health system that pays for the fracture and the rehabilitation but not for the assessment that would have found the loose component eighteen months earlier. Deterioration in one person is not a private event; it redistributes onto everyone around them.

This is why we test across disciplines rather than referring the ear to one specialist, the feet to another, and the memory to a third, each of whom sees a normal result within their own domain and sends the patient on. The interaction between the systems is the finding. Nobody looking at one system in isolation can see it.

Anyone with peripheral neuropathy, particularly diabetic neuropathy, and anyone who has had a fall or a near-fall in the past year. Anyone who has stopped doing something — stairs, showers without a rail, walking outside after dark — because of unsteadiness rather than pain. Anyone with dizziness, lightheadedness on standing, or a feeling of being off balance that has never been sorted out.

Also anyone on a medication list long enough that nobody has recently asked what the whole list is doing to their balance. That is its own review, and it is worth having.

You do not need a referral to be evaluated here.