In medical science, a lot of knowledge, time and money is invested in the development of new technologies that can contribute to a healthier life, early diagnosis of diseases and preferably a full recovery. Sometimes, however, it turns out that certain existing technologies can also be used for other, medically diagnostic, tasks. The research recently launched that uses earbuds to recognize early signs of Alzheimer's disease is a good example.
In particular, the researchers, from the École de Technologie Supérieure and Dartmouth University, are looking at deploying the microphones now found in earbuds, among other things, for filtering background noise. The goal is to investigate whether earbuds could be a simpler and more accessible alternative to eye-tracking devices now used to recognize early signs of Alzheimer's.
Loss of movement control
People with Alzheimer's disease show a loss of movement control, in addition to cognitive decline. One of the first signs of this decline can be noticed in involuntary eye movements known as saccades. These rapid eye movements in Alzheimer's patients are often slower, less precise or delayed compared to those in healthy individuals. “Eye movements are fascinating because they are among the fastest and most precise movements in the human body, and thus depend on both excellent motor skills and cognitive functioning,” says researcher Arian Shamei.
To recognize and analyze these saccades, patients are monitored using eye-tracking devices. An examination not easily accessible to most people. The researchers are now looking at an alternative method that thus involve earbuds, and particularly their built-in microphones. “We use earbuds with in-ear microphones that pick up physiological signals from the body. Our goal is to develop health monitoring algorithms for hearing aids capable of long-term continuous monitoring and early disease detection,” says researcher Miriam Boutros.
Being able to recognize early symptoms for Alzheimer's disease by examining a patient's eyes and pupil movements is not new. A few years ago, for example, American scientists discovered that with so-called pupil-response testing, it is also possible to determine whether someone is at greater risk of developing Alzheimer's disease. To do so, they developed a smartphone app that tracks minute changes in a person's pupil size.
Vibrations of the eardrum
Eye movements, including saccades, cause vibrations of the eardrums that can be picked up by sensitive microphones in the ear. The researchers are conducting experiments with volunteers, using both hearing aids and conventional eye-trackers. Their goal is to identify signals that correspond to saccades and distinguish between healthy signals and others indicative of neurological disorders such as Alzheimer's disease. They hope their research will one day lead to devices that can perform non-invasive continuous monitoring for Alzheimer's disease and other neurological diseases.
“Although the current project focuses on long-term monitoring of Alzheimer's disease, we eventually want to address other diseases and be able to differentiate between them based on symptoms that can be monitored via in-ear signals,” Shamei said.
The research is led by Rachel Bouserhal of the Research in Hearing Health and Assistive Devices (RHAD) Laboratory at École de Technologie Supérieure and Chris Niemczak of Dartmouth University's Geisel School of Medicine.
