Shigeta Fujitani - Academia.edu (original) (raw)

Papers by Shigeta Fujitani

Cerebral cortex, Mar 1, 2024

Cerebral Cortex, Feb 15, 2022

Decoding the inner representation of a word meaning from human cortical activity is a substantial... more Decoding the inner representation of a word meaning from human cortical activity is a substantial challenge in the development of speech brain-machine interfaces (BMIs). The semantic aspect of speech is a novel target of speech decoding that may enable versatile communication platforms for individuals with impaired speech ability; however, there is a paucity of electrocorticography studies in this field. We decoded the semantic representation of a word from single-trial cortical activity during an imageability-based property identification task that required participants to discriminate between the abstract and concrete words. Using high gamma activity in the language-dominant hemisphere, a support vector machine classifier could discriminate the 2-word categories with significantly high accuracy (73.1 ± 7.5%). Activities in specific time components from two brain regions were identified as significant predictors of abstract and concrete dichotomy. Classification using these feature components revealed that comparable prediction accuracy could be obtained based on a spatiotemporally targeted decoding approach. Our study demonstrated that mental representations of abstract and concrete word processing could be decoded from cortical high gamma activities, and the coverage of implanted electrodes and time window of analysis could be successfully minimized. Our findings lay the foundation for the future development of semanticbased speech BMIs.

Surgery for Cerebral Stroke, 2019

A3-A3 side-to-side bypass (A3-A3 bypass) is commonly used for revascularization of the anterior c... more A3-A3 side-to-side bypass (A3-A3 bypass) is commonly used for revascularization of the anterior cerebral artery territory; however, it is indicated in few patients. This study investigated the indications for A3-A3 bypass based on our clinical experience and a literature review. The study included 5 patients (3 men and 2 women) who underwent A3-A3 bypass between April 2012 and November 2017. The patients were in their 20s (n = 2), 40s (n = 1), and 50s (n = 2). The diagnoses included unruptured anterior communicating artery aneurysm treated with trapping (n = 1), recurrent enlargement of the anterior communicating artery after clipping (n = 1), anterior cerebral artery dissection (n = 1), anterior cerebral artery stenosis with cerebral infarction (n = 1), and traumatic distal anterior cerebral artery aneurysm (n = 1). A3-A3 bypass was completed and patency was confirmed in all patients. The requirements for A3-A3 bypass performance include suturing skills for anastomosis, appropriate selection of donor and recipient vessels, and comprehensive preoperative assessment. The indications for A3-A3 bypass are various. When performing a craniotomy for anterior communicating artery aneurysms and distal anterior cerebral artery aneurysms, the A3-A3 bypass can be used as a rescue technique. Therefore, stroke surgeons should master the essential skills. Training in suturing skills is an important part of preparation for the procedure.

Journal of stroke and cerebrovascular diseases, Oct 1, 2021

Objectives : An association has been reported between delays in the onset-to-door (O2D) time for ... more Objectives : An association has been reported between delays in the onset-to-door (O2D) time for mechanical thrombectomy (MT) and outbreaks of coronavirus disease 2019 (COVID-19). However, the association between other MT time courses or functional outcomes and COVID-19 outbreaks remains unclear. We compared the time courses of stroke pathways or functional outcomes in 2020 (the COVID-19 era) with those in 2019 (the pre-COVID-19 era) in Tokyo, Japan. Materials and Methods : This retrospective observational study used data from the Tokyo-tama-REgistry of Acute endovascular Thrombectomy (TREAT), a multicenter registry of MT for acute large vessel occlusion in the Tokyo Metropolitan Area. Patients who had undergone acute MT from January 2019 to December 2020 were included. Patients were classified by the year they had undergone MT (2019 or 2020). Results : In total, 477 patients were analyzed. O2D time was significantly longer in 2020 (146.0 min) than in 2019 (105.0 min; p=0.034). No significant difference in door-to-puncture time (D2P) time or modified Rankin Scale (mRS) score 0–2 at 90 days was seen between 2019 and 2020. In the subgroup analysis, O2D time was significantly longer in the first half of 2020 compared with 2019. Multivariable logistic regression analysis revealed that the year 2020 was a independent predictor of longer O2D time, but not for mRS score 0–2 at 90 days. Conclusions : Although O2D time was significantly longer in the COVID-19 compared with the pre-COVID-19 era, D2P may not be significantly delayed and functional outcomes may not be different, despite the COVID-19 pandemic.

Surgical Neurology International, Jan 3, 2020

is is an open-access article distributed under the terms of the Creative Commons Attribution-Non... more is is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.

Journal of Neurosurgery, Mar 1, 2017

OBJECTIVE Chronic subdural hematoma (CSDH) is a common form of intracranial hemorrhage with a rec... more OBJECTIVE Chronic subdural hematoma (CSDH) is a common form of intracranial hemorrhage with a recurrence rate of 9.2%-26.5% after bur hole surgery. Occasionally patients with bilateral CSDH undergo unilateral surgery because the contralateral hematoma is deemed to be asymptomatic, and in some of these patients the contralateral hematoma may subsequently enlarge, requiring additional surgery. The authors investigated the factors related to the growth of these hematomas. METHODS Ninety-three patients with bilateral CSDH who underwent unilateral bur hole surgery at Aizu Chuo Hospital were included in a retrospective analysis. Findings on preoperative MRI, preoperative thickness of the drained hematoma, and the influence of antiplatelet or anticoagulant drugs were considered and evaluated in univariate and multivariate analyses. RESULTS The overall growth rate was 19% (18 of 93 hematomas), and a significantly greater percentage of the hematomas that were iso-or hypointense on preoperative T1-weighted imaging showed growth compared with other hematomas (35.4% vs 2.3%, p < 0.001). Multivariate logistic regression analysis showed that findings on preoperative T1-weighted MRI were the sole significant predictor of hematoma growth, and other factors such as antiplatelet or anticoagulant drug use, patient age, patient sex, thickness of the treated hematoma, and T2-weighted MRI findings were not significantly related to hematoma growth. The adjusted odds ratio for hematoma growth in the T1 isointense/hypointense group relative to the T1 hyperintense group was 25.12 (95% CI 3.89-51.58, p < 0.01). CONCLUSIONS The findings of preoperative MRI, namely T1-weighted sequences, may be useful in predicting the growth of hematomas that did not undergo bur hole surgery in patients with bilateral CSDH.

Interdisciplinary Neurosurgery, Jun 1, 2021

This study evaluated the usefulness of computed tomography (CT) angiography for the detection of ... more This study evaluated the usefulness of computed tomography (CT) angiography for the detection of high-risk aortas for carotid artery stenting (CAS). We investigated changes in the treatment method and modifications of endovascular techniques according to the information from CT angiography. CT angiography using three-dimensional and multi-planar reconstruction was performed in 43 consecutive patients with carotid artery stenoses intended to undergo CAS. Two neurosurgeons evaluated the images and estimated the risk and difficulties of CAS. CT angiography clearly depicted the entire aorta, the supra-aortic vessels, and the ilio-femoral arteries in all patients. Abnormal vascular findings were found in 17 patients. High-risk aortic lesions for CAS were detected in 5 patients, including thick aortic plaques with thrombi in 2. We changed the treatment strategy from CAS to carotid endarterectomy (CEA) in these 2 patients. CT angiograms proved very useful in evaluating the approach routes of CAS in 12 patients. One patient had dissecting aneurysm of the thoracic aorta and another had aberrant right vertebral artery. In these two, the treatment strategy was changed from CAS to CEA. The treatment method was changed in 4 patients in total. CT angiography is useful for the detection of high-risk aortas for CAS and for the evaluation of safe approaches to the carotid artery.

Journal of neurosurgery, Apr 18, 2022

BACKGROUND Gastrointestinal stromal tumors (GISTs) are common subepithelial tumors that rarely me... more BACKGROUND Gastrointestinal stromal tumors (GISTs) are common subepithelial tumors that rarely metastasize to the intracranial space. Because the standard treatment for metastatic intracranial GISTs has not been established, multimodal therapies are needed, especially in the case of skull base metastasis. However, its outcome has not always been favorable. The authors report the longest known surviving case of skull base metastasis of GIST treated with imatinib only. OBSERVATIONS A 52-year-old male with a history of GIST presented with left facial swelling and numbness. Examinations revealed a 70-mm tumor occupying the left middle cranial fossa and the orbit. The authors performed transnasal endoscopic tumor biopsy for definitive diagnosis and reintroduced imatinib treatment. The tumor significantly decreased in size early after the introduction of imatinib, and symptoms completely disappeared within several weeks. The lesion has remained shrunk radiologically for 63 months, and the patient is continuously being followed up under imatinib treatment. LESSONS The authors reported a rare case of skull base metastasis of GIST successfully treated solely with systemic therapy with a tyrosine kinase inhibitor, achieving tumor control for over 5 years. This case suggests that tyrosine kinase inhibitors might play a key role in the multidisciplinary treatment for skull base metastases of GIST.

World Neurosurgery, Jul 1, 2020

Anomalous origin of the right vertebral artery from the right common carotid artery occurs rarely... more Anomalous origin of the right vertebral artery from the right common carotid artery occurs rarely. To the best of our knowledge, the medical literature contains no information about gray-scale and Doppler sonography findings in this anomaly, despite the extensive information available from angiographic studies and postmortem examinations. We present the case of a 32-year-old man who suffered from a sudden onset of hemiparesis on the left side. Doppler sonography revealed a partial thrombosis in the proximal part of right common carotid artery. The right vertebral artery was shown to originate from the proximal part of the right common carotid artery. The right vertebral artery was patent. Thus, the use of color Doppler sonography can aid in the diagnosis of some vascular anomalies.

Applied Psychophysiology and Biofeedback

Removal of the mesial temporal lobe (MTL) is an established surgical procedure that leads to seiz... more Removal of the mesial temporal lobe (MTL) is an established surgical procedure that leads to seizure freedom in patients with intractable MTL epilepsy; however, it carries the potential risk of memory damage. Neurofeedback (NF), which regulates brain function by converting brain activity into perceptible information and providing feedback, has attracted considerable attention in recent years for its potential as a novel complementary treatment for many neurological disorders. However, no research has attempted to artificially reorganize memory functions by applying NF before resective surgery to preserve memory functions. Thus, this study aimed (1) to construct a memory NF system that used intracranial electrodes to feedback neural activity on the language-dominant side of the MTL during memory encoding and (2) to verify whether neural activity and memory function in the MTL change with NF training. Two intractable epilepsy patients with implanted intracranial electrodes underwent a...

Neurofeedback (NF) shows promise in enhancing memory, but its application to the medial temporal ... more Neurofeedback (NF) shows promise in enhancing memory, but its application to the medial temporal lobe (MTL) still needs to be studied. Therefore, we aimed to develop an NF system for the memory function of the MTL and examine neural activity changes, and memory task score changes through NF training. We created a memory NF system using intracranial electrodes to acquire and visualise the neural activity of the MTL during memory encoding. Twenty trials of a tug-of-war game per session were employed for NF and designed to control neural activity bidirectionally (Up/Down condition). NF training was conducted with three patients with intractable epilepsy, and we observed an increasing difference in NF signal between conditions (Up−Down) as NF training progressed. Similarities and negative correlation tendencies between the transition of neural activity and the transition of memory function were also observed. Our findings demonstrate NF's potential to modulate MTL activity and memor...

Surgical Neurology International

Background: Common carotid artery occlusion (CCAO) is rare. Symptomatic lesions are resistant to ... more Background: Common carotid artery occlusion (CCAO) is rare. Symptomatic lesions are resistant to medical treatment and revascularization are often required, but there is no consensus on the treatment of CCAO. In this paper, two cases of symptomatic CCAO treated by carotid endarterectomy (CEA) with L-shaped ministernotomy, in which the lesions extended to the beginning part of the CCA, are reported. Case Description: Case 1 involved a 74-year-old man who presented with transient left limb numbness and an abnormal right visual field. Cerebrovascular angiography showed that the right CCA was occluded immediately after its origin and blood was supplied from the posterior circulation. CEA was performed with an L-shaped ministernotomy that allowed exposure of the CCA origin with minimal invasion. There were no complications associated with the sternal incision and he was discharged with a modified Rankin Scale (mRS) score of 0. Case 2 involved a 70-year-old man who presented with left hal...

Journal of Neurosurgery: Case Lessons

BACKGROUND Gastrointestinal stromal tumors (GISTs) are common subepithelial tumors that rarely me... more BACKGROUND Gastrointestinal stromal tumors (GISTs) are common subepithelial tumors that rarely metastasize to the intracranial space. Because the standard treatment for metastatic intracranial GISTs has not been established, multimodal therapies are needed, especially in the case of skull base metastasis. However, its outcome has not always been favorable. The authors report the longest known surviving case of skull base metastasis of GIST treated with imatinib only. OBSERVATIONS A 52-year-old male with a history of GIST presented with left facial swelling and numbness. Examinations revealed a 70-mm tumor occupying the left middle cranial fossa and the orbit. The authors performed transnasal endoscopic tumor biopsy for definitive diagnosis and reintroduced imatinib treatment. The tumor significantly decreased in size early after the introduction of imatinib, and symptoms completely disappeared within several weeks. The lesion has remained shrunk radiologically for 63 months, and the...

Resective surgery for mesial temporal lobe epilepsy (MTLE) carries the potential risk of memory d... more Resective surgery for mesial temporal lobe epilepsy (MTLE) carries the potential risk of memory decline. Neurofeedback (NF) which regulates brain activity and function, may be a promising solution for improving memory function. We constructed a memory-NF system using theta band power of electrocorticograms from the parahippocampal gyrus (PHG) and evaluated it with a preliminary study. As a result, we observed changes in theta-range oscillatory activity in PHG during NF training, and gained important insights for further developing the memory-NF system for memory enhancement.

Cerebral Cortex, 2022

Decoding the inner representation of a word meaning from human cortical activity is a substantial... more Decoding the inner representation of a word meaning from human cortical activity is a substantial challenge in the development of speech brain–machine interfaces (BMIs). The semantic aspect of speech is a novel target of speech decoding that may enable versatile communication platforms for individuals with impaired speech ability; however, there is a paucity of electrocorticography studies in this field. We decoded the semantic representation of a word from single-trial cortical activity during an imageability-based property identification task that required participants to discriminate between the abstract and concrete words. Using high gamma activity in the language-dominant hemisphere, a support vector machine classifier could discriminate the 2-word categories with significantly high accuracy (73.1 ± 7.5%). Activities in specific time components from two brain regions were identified as significant predictors of abstract and concrete dichotomy. Classification using these feature...

Journal of Stroke and Cerebrovascular Diseases, 2021

Objectives : An association has been reported between delays in the onset-to-door (O2D) time for ... more Objectives : An association has been reported between delays in the onset-to-door (O2D) time for mechanical thrombectomy (MT) and outbreaks of coronavirus disease 2019 (COVID-19). However, the association between other MT time courses or functional outcomes and COVID-19 outbreaks remains unclear. We compared the time courses of stroke pathways or functional outcomes in 2020 (the COVID-19 era) with those in 2019 (the pre-COVID-19 era) in Tokyo, Japan. Materials and Methods : This retrospective observational study used data from the Tokyo-tama-REgistry of Acute endovascular Thrombectomy (TREAT), a multicenter registry of MT for acute large vessel occlusion in the Tokyo Metropolitan Area. Patients who had undergone acute MT from January 2019 to December 2020 were included. Patients were classified by the year they had undergone MT (2019 or 2020). Results : In total, 477 patients were analyzed. O2D time was significantly longer in 2020 (146.0 min) than in 2019 (105.0 min; p=0.034). No significant difference in door-to-puncture time (D2P) time or modified Rankin Scale (mRS) score 0–2 at 90 days was seen between 2019 and 2020. In the subgroup analysis, O2D time was significantly longer in the first half of 2020 compared with 2019. Multivariable logistic regression analysis revealed that the year 2020 was a independent predictor of longer O2D time, but not for mRS score 0–2 at 90 days. Conclusions : Although O2D time was significantly longer in the COVID-19 compared with the pre-COVID-19 era, D2P may not be significantly delayed and functional outcomes may not be different, despite the COVID-19 pandemic.

Japanese Journal of Stroke, 2020

Cerebral cortex, Mar 1, 2024

Cerebral Cortex, Feb 15, 2022

Decoding the inner representation of a word meaning from human cortical activity is a substantial... more Decoding the inner representation of a word meaning from human cortical activity is a substantial challenge in the development of speech brain-machine interfaces (BMIs). The semantic aspect of speech is a novel target of speech decoding that may enable versatile communication platforms for individuals with impaired speech ability; however, there is a paucity of electrocorticography studies in this field. We decoded the semantic representation of a word from single-trial cortical activity during an imageability-based property identification task that required participants to discriminate between the abstract and concrete words. Using high gamma activity in the language-dominant hemisphere, a support vector machine classifier could discriminate the 2-word categories with significantly high accuracy (73.1 ± 7.5%). Activities in specific time components from two brain regions were identified as significant predictors of abstract and concrete dichotomy. Classification using these feature components revealed that comparable prediction accuracy could be obtained based on a spatiotemporally targeted decoding approach. Our study demonstrated that mental representations of abstract and concrete word processing could be decoded from cortical high gamma activities, and the coverage of implanted electrodes and time window of analysis could be successfully minimized. Our findings lay the foundation for the future development of semanticbased speech BMIs.

Surgery for Cerebral Stroke, 2019

A3-A3 side-to-side bypass (A3-A3 bypass) is commonly used for revascularization of the anterior c... more A3-A3 side-to-side bypass (A3-A3 bypass) is commonly used for revascularization of the anterior cerebral artery territory; however, it is indicated in few patients. This study investigated the indications for A3-A3 bypass based on our clinical experience and a literature review. The study included 5 patients (3 men and 2 women) who underwent A3-A3 bypass between April 2012 and November 2017. The patients were in their 20s (n = 2), 40s (n = 1), and 50s (n = 2). The diagnoses included unruptured anterior communicating artery aneurysm treated with trapping (n = 1), recurrent enlargement of the anterior communicating artery after clipping (n = 1), anterior cerebral artery dissection (n = 1), anterior cerebral artery stenosis with cerebral infarction (n = 1), and traumatic distal anterior cerebral artery aneurysm (n = 1). A3-A3 bypass was completed and patency was confirmed in all patients. The requirements for A3-A3 bypass performance include suturing skills for anastomosis, appropriate selection of donor and recipient vessels, and comprehensive preoperative assessment. The indications for A3-A3 bypass are various. When performing a craniotomy for anterior communicating artery aneurysms and distal anterior cerebral artery aneurysms, the A3-A3 bypass can be used as a rescue technique. Therefore, stroke surgeons should master the essential skills. Training in suturing skills is an important part of preparation for the procedure.

Journal of stroke and cerebrovascular diseases, Oct 1, 2021

Objectives : An association has been reported between delays in the onset-to-door (O2D) time for ... more Objectives : An association has been reported between delays in the onset-to-door (O2D) time for mechanical thrombectomy (MT) and outbreaks of coronavirus disease 2019 (COVID-19). However, the association between other MT time courses or functional outcomes and COVID-19 outbreaks remains unclear. We compared the time courses of stroke pathways or functional outcomes in 2020 (the COVID-19 era) with those in 2019 (the pre-COVID-19 era) in Tokyo, Japan. Materials and Methods : This retrospective observational study used data from the Tokyo-tama-REgistry of Acute endovascular Thrombectomy (TREAT), a multicenter registry of MT for acute large vessel occlusion in the Tokyo Metropolitan Area. Patients who had undergone acute MT from January 2019 to December 2020 were included. Patients were classified by the year they had undergone MT (2019 or 2020). Results : In total, 477 patients were analyzed. O2D time was significantly longer in 2020 (146.0 min) than in 2019 (105.0 min; p=0.034). No significant difference in door-to-puncture time (D2P) time or modified Rankin Scale (mRS) score 0–2 at 90 days was seen between 2019 and 2020. In the subgroup analysis, O2D time was significantly longer in the first half of 2020 compared with 2019. Multivariable logistic regression analysis revealed that the year 2020 was a independent predictor of longer O2D time, but not for mRS score 0–2 at 90 days. Conclusions : Although O2D time was significantly longer in the COVID-19 compared with the pre-COVID-19 era, D2P may not be significantly delayed and functional outcomes may not be different, despite the COVID-19 pandemic.

Surgical Neurology International, Jan 3, 2020

is is an open-access article distributed under the terms of the Creative Commons Attribution-Non... more is is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.

Journal of Neurosurgery, Mar 1, 2017

OBJECTIVE Chronic subdural hematoma (CSDH) is a common form of intracranial hemorrhage with a rec... more OBJECTIVE Chronic subdural hematoma (CSDH) is a common form of intracranial hemorrhage with a recurrence rate of 9.2%-26.5% after bur hole surgery. Occasionally patients with bilateral CSDH undergo unilateral surgery because the contralateral hematoma is deemed to be asymptomatic, and in some of these patients the contralateral hematoma may subsequently enlarge, requiring additional surgery. The authors investigated the factors related to the growth of these hematomas. METHODS Ninety-three patients with bilateral CSDH who underwent unilateral bur hole surgery at Aizu Chuo Hospital were included in a retrospective analysis. Findings on preoperative MRI, preoperative thickness of the drained hematoma, and the influence of antiplatelet or anticoagulant drugs were considered and evaluated in univariate and multivariate analyses. RESULTS The overall growth rate was 19% (18 of 93 hematomas), and a significantly greater percentage of the hematomas that were iso-or hypointense on preoperative T1-weighted imaging showed growth compared with other hematomas (35.4% vs 2.3%, p < 0.001). Multivariate logistic regression analysis showed that findings on preoperative T1-weighted MRI were the sole significant predictor of hematoma growth, and other factors such as antiplatelet or anticoagulant drug use, patient age, patient sex, thickness of the treated hematoma, and T2-weighted MRI findings were not significantly related to hematoma growth. The adjusted odds ratio for hematoma growth in the T1 isointense/hypointense group relative to the T1 hyperintense group was 25.12 (95% CI 3.89-51.58, p < 0.01). CONCLUSIONS The findings of preoperative MRI, namely T1-weighted sequences, may be useful in predicting the growth of hematomas that did not undergo bur hole surgery in patients with bilateral CSDH.

Interdisciplinary Neurosurgery, Jun 1, 2021

This study evaluated the usefulness of computed tomography (CT) angiography for the detection of ... more This study evaluated the usefulness of computed tomography (CT) angiography for the detection of high-risk aortas for carotid artery stenting (CAS). We investigated changes in the treatment method and modifications of endovascular techniques according to the information from CT angiography. CT angiography using three-dimensional and multi-planar reconstruction was performed in 43 consecutive patients with carotid artery stenoses intended to undergo CAS. Two neurosurgeons evaluated the images and estimated the risk and difficulties of CAS. CT angiography clearly depicted the entire aorta, the supra-aortic vessels, and the ilio-femoral arteries in all patients. Abnormal vascular findings were found in 17 patients. High-risk aortic lesions for CAS were detected in 5 patients, including thick aortic plaques with thrombi in 2. We changed the treatment strategy from CAS to carotid endarterectomy (CEA) in these 2 patients. CT angiograms proved very useful in evaluating the approach routes of CAS in 12 patients. One patient had dissecting aneurysm of the thoracic aorta and another had aberrant right vertebral artery. In these two, the treatment strategy was changed from CAS to CEA. The treatment method was changed in 4 patients in total. CT angiography is useful for the detection of high-risk aortas for CAS and for the evaluation of safe approaches to the carotid artery.

Journal of neurosurgery, Apr 18, 2022

BACKGROUND Gastrointestinal stromal tumors (GISTs) are common subepithelial tumors that rarely me... more BACKGROUND Gastrointestinal stromal tumors (GISTs) are common subepithelial tumors that rarely metastasize to the intracranial space. Because the standard treatment for metastatic intracranial GISTs has not been established, multimodal therapies are needed, especially in the case of skull base metastasis. However, its outcome has not always been favorable. The authors report the longest known surviving case of skull base metastasis of GIST treated with imatinib only. OBSERVATIONS A 52-year-old male with a history of GIST presented with left facial swelling and numbness. Examinations revealed a 70-mm tumor occupying the left middle cranial fossa and the orbit. The authors performed transnasal endoscopic tumor biopsy for definitive diagnosis and reintroduced imatinib treatment. The tumor significantly decreased in size early after the introduction of imatinib, and symptoms completely disappeared within several weeks. The lesion has remained shrunk radiologically for 63 months, and the patient is continuously being followed up under imatinib treatment. LESSONS The authors reported a rare case of skull base metastasis of GIST successfully treated solely with systemic therapy with a tyrosine kinase inhibitor, achieving tumor control for over 5 years. This case suggests that tyrosine kinase inhibitors might play a key role in the multidisciplinary treatment for skull base metastases of GIST.

World Neurosurgery, Jul 1, 2020

Anomalous origin of the right vertebral artery from the right common carotid artery occurs rarely... more Anomalous origin of the right vertebral artery from the right common carotid artery occurs rarely. To the best of our knowledge, the medical literature contains no information about gray-scale and Doppler sonography findings in this anomaly, despite the extensive information available from angiographic studies and postmortem examinations. We present the case of a 32-year-old man who suffered from a sudden onset of hemiparesis on the left side. Doppler sonography revealed a partial thrombosis in the proximal part of right common carotid artery. The right vertebral artery was shown to originate from the proximal part of the right common carotid artery. The right vertebral artery was patent. Thus, the use of color Doppler sonography can aid in the diagnosis of some vascular anomalies.

Applied Psychophysiology and Biofeedback

Removal of the mesial temporal lobe (MTL) is an established surgical procedure that leads to seiz... more Removal of the mesial temporal lobe (MTL) is an established surgical procedure that leads to seizure freedom in patients with intractable MTL epilepsy; however, it carries the potential risk of memory damage. Neurofeedback (NF), which regulates brain function by converting brain activity into perceptible information and providing feedback, has attracted considerable attention in recent years for its potential as a novel complementary treatment for many neurological disorders. However, no research has attempted to artificially reorganize memory functions by applying NF before resective surgery to preserve memory functions. Thus, this study aimed (1) to construct a memory NF system that used intracranial electrodes to feedback neural activity on the language-dominant side of the MTL during memory encoding and (2) to verify whether neural activity and memory function in the MTL change with NF training. Two intractable epilepsy patients with implanted intracranial electrodes underwent a...

Neurofeedback (NF) shows promise in enhancing memory, but its application to the medial temporal ... more Neurofeedback (NF) shows promise in enhancing memory, but its application to the medial temporal lobe (MTL) still needs to be studied. Therefore, we aimed to develop an NF system for the memory function of the MTL and examine neural activity changes, and memory task score changes through NF training. We created a memory NF system using intracranial electrodes to acquire and visualise the neural activity of the MTL during memory encoding. Twenty trials of a tug-of-war game per session were employed for NF and designed to control neural activity bidirectionally (Up/Down condition). NF training was conducted with three patients with intractable epilepsy, and we observed an increasing difference in NF signal between conditions (Up−Down) as NF training progressed. Similarities and negative correlation tendencies between the transition of neural activity and the transition of memory function were also observed. Our findings demonstrate NF's potential to modulate MTL activity and memor...

Surgical Neurology International

Background: Common carotid artery occlusion (CCAO) is rare. Symptomatic lesions are resistant to ... more Background: Common carotid artery occlusion (CCAO) is rare. Symptomatic lesions are resistant to medical treatment and revascularization are often required, but there is no consensus on the treatment of CCAO. In this paper, two cases of symptomatic CCAO treated by carotid endarterectomy (CEA) with L-shaped ministernotomy, in which the lesions extended to the beginning part of the CCA, are reported. Case Description: Case 1 involved a 74-year-old man who presented with transient left limb numbness and an abnormal right visual field. Cerebrovascular angiography showed that the right CCA was occluded immediately after its origin and blood was supplied from the posterior circulation. CEA was performed with an L-shaped ministernotomy that allowed exposure of the CCA origin with minimal invasion. There were no complications associated with the sternal incision and he was discharged with a modified Rankin Scale (mRS) score of 0. Case 2 involved a 70-year-old man who presented with left hal...

Journal of Neurosurgery: Case Lessons

BACKGROUND Gastrointestinal stromal tumors (GISTs) are common subepithelial tumors that rarely me... more BACKGROUND Gastrointestinal stromal tumors (GISTs) are common subepithelial tumors that rarely metastasize to the intracranial space. Because the standard treatment for metastatic intracranial GISTs has not been established, multimodal therapies are needed, especially in the case of skull base metastasis. However, its outcome has not always been favorable. The authors report the longest known surviving case of skull base metastasis of GIST treated with imatinib only. OBSERVATIONS A 52-year-old male with a history of GIST presented with left facial swelling and numbness. Examinations revealed a 70-mm tumor occupying the left middle cranial fossa and the orbit. The authors performed transnasal endoscopic tumor biopsy for definitive diagnosis and reintroduced imatinib treatment. The tumor significantly decreased in size early after the introduction of imatinib, and symptoms completely disappeared within several weeks. The lesion has remained shrunk radiologically for 63 months, and the...

Resective surgery for mesial temporal lobe epilepsy (MTLE) carries the potential risk of memory d... more Resective surgery for mesial temporal lobe epilepsy (MTLE) carries the potential risk of memory decline. Neurofeedback (NF) which regulates brain activity and function, may be a promising solution for improving memory function. We constructed a memory-NF system using theta band power of electrocorticograms from the parahippocampal gyrus (PHG) and evaluated it with a preliminary study. As a result, we observed changes in theta-range oscillatory activity in PHG during NF training, and gained important insights for further developing the memory-NF system for memory enhancement.

Cerebral Cortex, 2022

Decoding the inner representation of a word meaning from human cortical activity is a substantial... more Decoding the inner representation of a word meaning from human cortical activity is a substantial challenge in the development of speech brain–machine interfaces (BMIs). The semantic aspect of speech is a novel target of speech decoding that may enable versatile communication platforms for individuals with impaired speech ability; however, there is a paucity of electrocorticography studies in this field. We decoded the semantic representation of a word from single-trial cortical activity during an imageability-based property identification task that required participants to discriminate between the abstract and concrete words. Using high gamma activity in the language-dominant hemisphere, a support vector machine classifier could discriminate the 2-word categories with significantly high accuracy (73.1 ± 7.5%). Activities in specific time components from two brain regions were identified as significant predictors of abstract and concrete dichotomy. Classification using these feature...

Journal of Stroke and Cerebrovascular Diseases, 2021

Objectives : An association has been reported between delays in the onset-to-door (O2D) time for ... more Objectives : An association has been reported between delays in the onset-to-door (O2D) time for mechanical thrombectomy (MT) and outbreaks of coronavirus disease 2019 (COVID-19). However, the association between other MT time courses or functional outcomes and COVID-19 outbreaks remains unclear. We compared the time courses of stroke pathways or functional outcomes in 2020 (the COVID-19 era) with those in 2019 (the pre-COVID-19 era) in Tokyo, Japan. Materials and Methods : This retrospective observational study used data from the Tokyo-tama-REgistry of Acute endovascular Thrombectomy (TREAT), a multicenter registry of MT for acute large vessel occlusion in the Tokyo Metropolitan Area. Patients who had undergone acute MT from January 2019 to December 2020 were included. Patients were classified by the year they had undergone MT (2019 or 2020). Results : In total, 477 patients were analyzed. O2D time was significantly longer in 2020 (146.0 min) than in 2019 (105.0 min; p=0.034). No significant difference in door-to-puncture time (D2P) time or modified Rankin Scale (mRS) score 0–2 at 90 days was seen between 2019 and 2020. In the subgroup analysis, O2D time was significantly longer in the first half of 2020 compared with 2019. Multivariable logistic regression analysis revealed that the year 2020 was a independent predictor of longer O2D time, but not for mRS score 0–2 at 90 days. Conclusions : Although O2D time was significantly longer in the COVID-19 compared with the pre-COVID-19 era, D2P may not be significantly delayed and functional outcomes may not be different, despite the COVID-19 pandemic.

Japanese Journal of Stroke, 2020