Hyun-Joon Yoo - Academia.edu (original) (raw)

Papers by Hyun-Joon Yoo

Scientific Reports, Jan 27, 2021

Precise monitoring of the brain after a stroke is essential for clinical decision making. Due to ... more Precise monitoring of the brain after a stroke is essential for clinical decision making. Due to the non-invasive nature and high temporal resolution of electroencephalography (EEG), it is widely used to evaluate real-time cortical activity. In this study, we investigated the stroke-related EEG biomarkers and developed a predictive model for quantifying the structural brain damage in a focal cerebral ischaemic rat model. We enrolled 31 male Sprague-Dawley rats and randomly assigned them to mild stroke, moderate stroke, severe stroke, and control groups. We induced photothrombotic stroke targeting the right auditory cortex. We then acquired EEG signal responses to sound stimuli (frequency linearly increasing from 8 to 12 kHz with 750 ms duration). Power spectral analysis revealed a significant correlation of the relative powers of alpha, theta, delta, delta/alpha ratio, and (delta + theta)/(alpha + beta) ratio with the stroke lesion volume. The auditory evoked potential analysis revealed a significant association of amplitude and latency with stroke lesion volume. Finally, we developed a multiple regression model combining EEG predictors for quantifying the ischaemic lesion (R 2 = 0.938, p value < 0.001). These findings demonstrate the potential application of EEG as a valid modality for monitoring the brain after a stroke. Stroke is a neurological disorder caused by vascular disease, including cerebral infarction, intracerebral haemorrhage, and subarachnoid haemorrhage 1. It is the second leading cause of death worldwide and its treatment incurs a substantial economic cost 2. Consequently, comprehensive clinical guidelines for stoke management have been complied as countermeasures for reducing stroke-related disabilities 3. However, the global burden of stroke remains high 2. Moreover, stroke is a heterogeneous condition and its clinical course is difficult to predict. Further, there may be progressive stroke-induced brain damage during the subacute stage, which further aggravates the neurological outcome 4. Therefore, precise monitoring and evaluation of the brain injury are paramount for establishing effective treatment strategies and prognosis prediction. With advances in modern medicine, various efficient imaging modalities and evaluation tools have been developed to monitor and evaluate the post-stroke brain condition. Among them, computed tomography (CT) and magnetic resonance imaging (MRI) are the most widely used modalities due to their sensitivity to brain ischaemic or haemorrhagic changes and their provision of structural information 5. Therefore, it is recommended that patients admitted to hospitals with suspected stroke undergo immediate brain imaging evaluation 3. However, these neuroimaging modalities are expensive and may not be available in some facilities. Therefore, the use of CT or MRI for repetitive monitoring is limited despite being the diagnostic tools of choice for stroke detection. However, although these imaging modalities provide detailed anatomical information about the brain; they do not assess the functional status of the brain. There are other alternative imaging techniques such as positron emission tomography (PET), which is often used to evaluate brain metabolism. However, the associated radiation exposure and high costs limit its feasibility as a routine clinical monitoring tool 6. Stroke-related clinical scales such as the National Institutes of Health Stroke Scale (NIHSS) and the Mini-Mental State Examination (MMSE) are also widely used 7,8. Although the administration of these scales requires well-trained physicians, they are relatively simple to implement and have been reported useful for estimating the neurologic deficit changes in patients over time 9. However, they require appropriate cooperation from patients and cannot be administered to patients who are aphasic or under anaesthesia. Additionally, clinical scales are prone to be affected by the patients' general condition including fatigue, pain, and post-stroke depression, which makes it difficult for clinicians to determine the patients' status 10. This makes it difficult to evaluate the patients' status objectively.

Scientific Reports, Jan 27, 2021

Precise monitoring of the brain after a stroke is essential for clinical decision making. Due to ... more Precise monitoring of the brain after a stroke is essential for clinical decision making. Due to the non-invasive nature and high temporal resolution of electroencephalography (EEG), it is widely used to evaluate real-time cortical activity. In this study, we investigated the stroke-related EEG biomarkers and developed a predictive model for quantifying the structural brain damage in a focal cerebral ischaemic rat model. We enrolled 31 male Sprague-Dawley rats and randomly assigned them to mild stroke, moderate stroke, severe stroke, and control groups. We induced photothrombotic stroke targeting the right auditory cortex. We then acquired EEG signal responses to sound stimuli (frequency linearly increasing from 8 to 12 kHz with 750 ms duration). Power spectral analysis revealed a significant correlation of the relative powers of alpha, theta, delta, delta/alpha ratio, and (delta + theta)/(alpha + beta) ratio with the stroke lesion volume. The auditory evoked potential analysis revealed a significant association of amplitude and latency with stroke lesion volume. Finally, we developed a multiple regression model combining EEG predictors for quantifying the ischaemic lesion (R 2 = 0.938, p value < 0.001). These findings demonstrate the potential application of EEG as a valid modality for monitoring the brain after a stroke. Stroke is a neurological disorder caused by vascular disease, including cerebral infarction, intracerebral haemorrhage, and subarachnoid haemorrhage 1. It is the second leading cause of death worldwide and its treatment incurs a substantial economic cost 2. Consequently, comprehensive clinical guidelines for stoke management have been complied as countermeasures for reducing stroke-related disabilities 3. However, the global burden of stroke remains high 2. Moreover, stroke is a heterogeneous condition and its clinical course is difficult to predict. Further, there may be progressive stroke-induced brain damage during the subacute stage, which further aggravates the neurological outcome 4. Therefore, precise monitoring and evaluation of the brain injury are paramount for establishing effective treatment strategies and prognosis prediction. With advances in modern medicine, various efficient imaging modalities and evaluation tools have been developed to monitor and evaluate the post-stroke brain condition. Among them, computed tomography (CT) and magnetic resonance imaging (MRI) are the most widely used modalities due to their sensitivity to brain ischaemic or haemorrhagic changes and their provision of structural information 5. Therefore, it is recommended that patients admitted to hospitals with suspected stroke undergo immediate brain imaging evaluation 3. However, these neuroimaging modalities are expensive and may not be available in some facilities. Therefore, the use of CT or MRI for repetitive monitoring is limited despite being the diagnostic tools of choice for stroke detection. However, although these imaging modalities provide detailed anatomical information about the brain; they do not assess the functional status of the brain. There are other alternative imaging techniques such as positron emission tomography (PET), which is often used to evaluate brain metabolism. However, the associated radiation exposure and high costs limit its feasibility as a routine clinical monitoring tool 6. Stroke-related clinical scales such as the National Institutes of Health Stroke Scale (NIHSS) and the Mini-Mental State Examination (MMSE) are also widely used 7,8. Although the administration of these scales requires well-trained physicians, they are relatively simple to implement and have been reported useful for estimating the neurologic deficit changes in patients over time 9. However, they require appropriate cooperation from patients and cannot be administered to patients who are aphasic or under anaesthesia. Additionally, clinical scales are prone to be affected by the patients' general condition including fatigue, pain, and post-stroke depression, which makes it difficult for clinicians to determine the patients' status 10. This makes it difficult to evaluate the patients' status objectively.