A new method for early detection of Alzheimer’s disease could involve listening to the patient’s eyes via microphones placed in their ears.

This is all caused by a type of eye movement called a saccade. One of the very first signs of Alzheimer’s disease is a subtle slowness and imprecision of these tiny adjustments of the eyeballs.

The type of equipment typically required to track saccades could make analysis tricky, but strategically placed microphones designed to listen for normal body functions could instead measure movements.

A team of researchers led by electrical engineer Rachel Bouserhal from École de Technologie Supérieure in Canada and neuroscientist Chris Niemczak from Dartmouth College in the United States aims to test the technique on 35 Alzheimer’s patients to evaluate its effectiveness.

“Eye movements are fascinating because they are among the fastest and most precise movements in the human body, so they rely on both excellent motor skills and cognitive functioning,” says electrical engineer Arian Shamei from the School of Higher Technology.

To construct a meaningful visual image of an image or scene, our eyes perform a series of rapid, coordinated movements, fixing their attention on one point after another for tens of milliseconds at a time. You may have seen them if you’ve ever closely observed someone reading or observed their rapid eye movement during REM sleep.

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These are jerksand for a patient with Alzheimer’s, small movements become slower and less precise as motor control deteriorates. It’s very subtle at first, just a few milliseconds, but the changes becomes more pronounced as the disease progresses.

Scientists believe saccadic latency has the potential as an early diagnostic tool for Alzheimer’s disease, one that is inexpensive, non-invasive, painless and accessible to people with different literacy levels. But eye-tracking equipment isn’t always portable or accessible, so the researchers thought another option might work: a type of technology called auditory.

“It’s an earphone with in-ear microphones that captures physiological signals from the body,” says electrical engineer Miriam Boutros from the School of Higher Technology.

“Our goal is to develop hearing aid health monitoring algorithms that can provide long-term continuous monitoring and early disease detection.”

The movements of your eyes, including jerks, produce tiny vibrations in your eardrums. Most people cannot hear them because the body and brain are able to filter them; in fact, patients with a rare condition called superior canal dehiscence syndrome can hear his own eyeballs moving.

But a sensitive microphone can detect these vibrations. To determine whether they can provide enough information to serve as a diagnostic tool, researchers will equip 35 patients diagnosed with Alzheimer’s disease or mild cognitive impairment and 35 healthy controls with eye tracking devices and hearing aids. .

It is hoped that their findings will contribute to the development of a portable tool that can not only diagnose Alzheimer’s disease earlier, but also track the progression of the disease. And since Alzheimer’s disease is not the only disease that can manifest saccadic latency, the principle could also be applied elsewhere.

“While the current project focuses on long-term monitoring of Alzheimer’s disease,” Shamei says“Eventually, we would like to tackle other diseases and be able to differentiate them based on symptoms that can be tracked using in-ear signals.”

The team presented their work at 187th Meeting of the Acoustical Society of America.