Noninvasive Wearable RF Device Towards Monitoring Brain Atrophy and Lateral Ventricle Enlargement

Abstract

Alzheimer's disease is the most common form of neurodegenerative disease and a leading cause of dementia today. A pathological effect of Alzheimer's disease is brain atrophy, which is the progressive shrinkage of the brain volume and weight. Another effect of Alzheimer's disease is the enlargement of lateral ventricles in the brain. Currently, MRI and CT scanners can detect and show images of the brain during different stages of Alzheimer's disease. However, its limited accessibility, high costs, and static structure make it inconvenient for some to use. This paper presents the design and novel application of a wearable device comprising of flexible microwave antennas, with an operating frequency range of 800 MHz to 2.5 GHz, that detects the progression of brain atrophy and lateral ventricle enlargement in patients with Alzheimer's at the earliest stage possible. The operating principle of the antennas are simulated in near field using CST and the device is experimentally validated using lamb brain samples and samples representing cerebral spinal fluid (CSF). The measured reflection coefficients (S11) and transmission coefficients (S21) were found to correlate with changes in brain volume and changes in CSF volume successfully, thus giving an indication of the progression of Alzheimer's disease in a patient.

Integrated Flexible Hybrid Silicone-Textile Dual-Resonant Sensors and Switching Circuit for Wearable Neurodegeneration Monitoring Systems

“…Similarly, in the case of severe neurodegeneration, around 96 ml of salt was mixed with 150 ml of coconut oil to create the CSF phantom used in the experiment. This method was used based on the work performed in [7] where the authors fabricated different sizes of CSF objects to simulate the characteristic of enlarged lateral ventricles. Although the fabricated CSF objects do not accurately represent the fluidic nature of CSF, the samples provide a convenient way of performing the experiments for lateral ventricle enlargement to evaluate the performance of the sensors and switching circuit.…”

“…Microwave medical imaging has been used for stroke and cancer detection successfully [5], [6]. The authors have also developed and tested an initial wearable device, consisting of inkjet-printed antennas for detecting and monitoring brain atrophy and lateral ventricle enlargement, which is discussed in [7]. In that work, the minimum brain atrophy that could be detected by the antennas was 5%.…”

“…In addition, the smallest N increase in lateral ventricle enlargement that could be detected was a volume increase of 22.6 mm 3 . The work described in [7] was, to the authors' knowledge, the first study conducted for monitoring neurodegenerative disease using microwave sensing techniques. A microwave head imaging system typically consists of a device containing antenna sensors that are placed on the body under test, and a vector network analyser (VNA) that is used to generate and receive microwave signals from each of the antenna elements.…”

Parallel Delay Multiply and Sum Algorithm for Microwave Medical Imaging Using Spark Big Data Framework

“…A wearable and portable device in a hat-like shape proposed in our previous work [42] was used. The device contains an array of six flexible antennas created using thin polyethylene terephthalate.…”

“…The total weight of the device (components include a hat, two switching circuits and six sensors) is 291.7 g. The insertion loss of the proposed system is −3.9 dB, which is slightly larger due to the flexibility of the device. Further information about the switching systems, VNA and a PC can be found in [42].…”