Alzheimer's disease (AD) is a neurodegenerative disease affecting the prefrontal cortex, among other areas of the brain. This disease affects seniors and the risk of suffering from it increases with age. It is estimated that 44% of the American population from ages 65 to 74 have Alzheimer's disease, and 38% for American's aged 85 or older. By 2050, it is estimated that 51% of Americans aged 65 years or older will suffer from AD.
Some of the current technologies to diagnose this disease include MRI and CT scans. Unfortunately, these technologies are very expensive and require specialized personel to install, maintain, operate and analyze the data.
But what if there was a way to early detect Alzheimers?
This project involved building a near-infrared spectrometer which is affordable to reduce cost to researchers. The device's design goal was to be wearable, comfortable, and minimalist so that the patient and researcher could have a better experience during tests. The concept pitch raised $11,000 for research and development funding which jump-started this project.
The design direction was initiated by Camille April Le Quere and the NIRS was created by a team of five individuals (David Livermore, Duncan Polley, Emmanuel Wilson, Tori-Lynn Temple, and Camille April Le Quere). This project was ongoing for 8 months with the core team and I was brought on and responsible for tweaking some of the initial proposals. I ultimately became the main Solidworks and rendering individual for the team.
Near-Infrared spectroscopy is used in this Alzheimer Band. This is a brain imaging technique that emits light at wavelengths near infrared, which is in the range of 750-950nm, traverses skin, bones, and brain matter. A light near infrared is injected into the brain, specifically into the prefrontal region. As the light enters the human tissues, some get absorbed, meanwhile some are scattered. From the scattered light, a portion comes back within a few centimeters from a light source. The larger the emitter-detector distance, the deeper the signal penetrates into brain matter.
From the change of absorption, one can determine the concentration of oxy- and deoxygenated hemoglobin flowing in the prefrontal cortex. These measurements can then indicate anomalies that could be caused by Alzheimer's disease.
The image below shows the optode holder, which is a set of light emitters and photodetectors which are held to the head. The photodetector is on each corner of the optode holder and it uses a high speed silicon PIN diode. The receiving circuit board located behind is composed of a current to voltage converter, an amplifier stage, and a low-pass filter. There needs to be a total of four receiving circuits in the final implementation. Once this signal is processed by receiving circuitry, it is converted to a digital signal for further processing and analysis.