A Dynamic Mode Decomposition Method for Modal Analysis of Human Brain Diagnosis

Abstract

Modal analysis is a strong tool of mechanical diagnosis and behavior of bodies and structures. The method can be employed for human head as a body to recognize its natural frequencies. Brain injury can be destructive around the brain’s resonant frequencies with the external applied loading and motion. Vibrations due to an assault on the head are sent throughout the brain under impacts or high motions. These waves propagate and attenuate at different rates within the brain depending on the magnitude and direction of the impact loading or motion. By conducting modal analysis of the brain and identifying its resonant frequencies we can measure the risk of injury and reduce or possibly even eliminate vibrations in these frequency ranges. This paper employs a finite elements method to simulate the impacts for different impact angles on a human head. A numerical technique based on dynamic mode decomposition (DMD) will be used to extract the modal properties for the brain tissue in regions near the corpus callosum and brain stem. The study aims to identify a frequency range in which the brain is more susceptible to vibration with the end goal of better understanding the brain in the frequency domain and preventing future TBIs. Three modal frequencies were identified with frequency ranges of 44–68Hz, 68–155Hz, and 114–299Hz. It is found that the impact angle, displacement direction, and region of the brain have a significant impact on the modal response of brain tissue during any impact. The study also provides insight into the effects of impact angle, displacement direction, and different regions of the brain.