Evaluating Interhemispheric Synchronization with Hemodynamic Oscillation in Acute Stroke Patients

  • 陸 怡萱

Student thesis: Doctoral Thesis


In stroke vascular pathology is related to the remodeling of the neurovascular and profound change of capillary flow pattern The cerebral autoregulation (CA) is hypothesized to be damaged in stroke patient which may cause the imbalance in synchronization of hemodynamic oscillation within two hemispheres Among various neuroimaging techniques near-infrared spectroscopy (NIRS) is a promising neuro-imaging technique to explore the changes of inter-oscillatory synchronization in both resting and motor task conditions The aims of this study were to evaluate the interhemispheric synchronization during hemodynamic oscillation in acute stroke patients A twenty-channel NIRS system was used to measure the concentration of hemoglobin at prefrontal cortex (PFC) supplementary motor cortex (SMA) and primary motor cortex (M1) in both hemispheres the measurement in resting state and motor task were conducted for acute unilateral stroke patients at 7th day and 14th day after stroke onset According to infarct volume and region the stroke patients were divided into three groups: large infarct volume (LIV) middle infarct volume (MIV) and small infarct volume (SIV) In resting state condition subjects were asked to sit comfortably with minimum movement for 5 minutes In addition to magnitude coherence function the wavelet-based phase coherence (PC) of NIRS data was utilized to estimate the phase synchronization of both hemispheres Our results showed that the PC value in 0 06-0 15 Hz interval and 0 02-0 06 Hz interval exhibited significant lower in the LIV group than the SIV group (control group) at 14th day after stroke onset In motor task condition subjects were asked to perform the finger tapping in a self-pace fashion using their index finger and middle finger alternatively The tasks were executed at 10- second active followed by 20-second of resting We observed that the lower HbD (HbO-HbR) was found in MIV stroke group compared to SIV stroke group However it did not reach significant level of difference For further investigation of in the time-course change of acute stroke we compare the infarct volume from MRI and HbD from NIRS at two stroke phases The result showed that infarct volume decreased as the increase in the HbD This indicates that functional neuron activity became stronger when stroke recovery improved In conclusion we examined the cerebral autoregulation and neuron activity in acute unilateral stroke patients at two different stroke phases Different phase coherence of interhemispheric hemodynamics among LIV MIV and SIV stroke patients group indicates altered impaired cerebral autoregulation Moreover different acute stroke phase might reflect the effects of brain neuron damage and response to the event-related optical signal
Date of Award2020
Original languageEnglish
SupervisorJia-Jin Chen (Supervisor)

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