A Signal Analysis Algorithm for Determining Brain Compliance Non-Invasively

Abstract

Patients with increased intracranial pressure head injury, subarachnoid hemorrhage, and intracerebral (ICP) caused by hydrocephalus or brain injury have poor hematoma2. This approach is based on evidence that the brain compliance or increased brain stiffness. The condition intracranial pressure pulse is transmitted from the is commonly treated by a surgical diversion of cerebrospinal intracranial space into the endolymph of the inner ear via fluid (CSF) through placement of a ventriculoperitoneal (VP) a patent cochlear aqueduct and thence backward over the shunt. These inserted devices frequently fail and require middle ear ossicles to the tympanic membrane2'3'45.replacement. Assessment of failed devices typically requires Thus,er exis to capnura an invasive surgical procedure to implant an ICP sensor.Thus, there exists a good non-invasive way to capture Brain compliance can be determined non-invasively by the ICP waveform. An analysis of this waveform and a companng the intracranial pressure (ICP) waveform to the comparison to a timing reference signal, such as an digital artery waveform. The ICP waveform is derived from electrocardiogram (EKG), a carotid artery pulse, or a a piezo sensor snugged into the external ear canal and worn digital artery pulse reveals a way to quantify brain as a headset. The digital artery waveform is derived from a compliance. This comparison shows a near-linear time standard pulse oximeter.Digital signal processing shift of the ICP signal as compliance worsens.performed on sampled data from these two sensors shows a time-lag or phase relationship between the two waves which widens with worsening brain stiffness or compliance. An II. METHODOLOGY algorithm is presented that shows how these signals can be used to compute brain compliance. An instrument designed Algorithm to calculate real-time brain compliance is described.The Fourier Transform (FT) transforms a Keywords-Algorithm, brain compliance, Fourier mathematical signal in the time domain into one Transform, Fast Fourier Transform, hydrocephalus, represented by real and imaginary parts in the frequency intracranial pressure, phase angle domain. The FT operates solely on continuous time signals. Its analog for discrete time signals is the Discrete I. INTRODUCTION Fourier Transform (DFT). The DFT transforms n real Brain injury can occur when excessive cerebrospinal valued discrete time samples of a signal into n values fluid (CSF) is trapped within the cranium causing consisting of real and imaginary components. The DFT is increasing pressure If the pressure is not immediately a computationally intensive algorithm. It is typically relieved, back-logged CSF will prevent arterial blood computed using the Fast Fourier Transform (FFT), a from entering the brain eventually leading to brain-death. computationally efficient algorithm. fromyenteringcthephralin eventually linic tobin-deatin oThe FFT provides information about the frequency Hydrocephalus is a chronic condition of content of a signal by resolving the frequency into n malabso...