Tuning Method of PI Controller for Given Damping Coefficient

Yohei Okada,Yuji Yamakawa,Takanori Yamazaki,Shigeru Kurosu 제어로봇시스템학회 2006 제어로봇시스템학회 국제학술대회 논문집 Vol.2006 No.10

Explainable artificial intelligence in emergency medicine: an overview

Okada Yohei,Ning Yilin,Ong Marcus Eng Hock 대한응급의학회 2023 Clinical and Experimental Emergency Medicine Vol.10 No.4

Artificial intelligence (AI) and machine learning (ML) have potential to revolutionize emergency medical care by enhancing triage systems, improving diagnostic accuracy, refining prognostication, and optimizing various aspects of clinical care. However, as clinicians often lack AI expertise, they might perceive AI as a “black box,” leading to trust issues. To address this, “explainable AI,” which teaches AI functionalities to end-users, is important. This review presents the definitions, importance, and role of explainable AI, as well as potential challenges in emergency medicine. First, we introduce the terms explainability, interpretability, and transparency of AI models. These terms sound similar but have different roles in discussion of AI. Second, we indicate that explainable AI is required in clinical settings for reasons of justification, control, improvement, and discovery and provide examples. Third, we describe three major categories of explainability: pre-modeling explainability, interpretable models, and post-modeling explainability and present examples (especially for post-modeling explainability), such as visualization, simplification, text justification, and feature relevance. Last, we show the challenges of implementing AI and ML models in clinical settings and highlight the importance of collaboration between clinicians, developers, and researchers. This paper summarizes the concept of “explainable AI” for emergency medicine clinicians. This review may help clinicians understand explainable AI in emergency contexts.

Application of Pluripotent Stem Cells to the Research on Neurological Disorders

Yohei Okada 한국실험동물학회 2014 한국실험동물학회 학술발표대회 논문집 Vol.2014 No.8

Transcranial direct current stimulation combined with action observation and electromyographic biofeedback training in a patient with writer's cramp

Yohei Okada,Chiharu Shibamoto,Yukari Osumi,Chihiro Asano,Riho Takeuchi,Sachio Nabeshima,Shu Morioka,Koji Shomoto 대한파킨슨병및이상운동질환학회 2018 Journal Of Movement Disorders Vol.11 No.2

We present a 47-year-old right-handed woman with a 15-year history of writer's cramp provided with six sessions of cathodal transcranial direct current stimulation (tDCS) combined with her observation of the writing actions performed by a healthy subject plus electromyographic (EMG) biofeedback training to decrease EMG activities of her right forehand muscles during writing for 30 min, 1 or 2/week for 4 weeks. She showed the improvement of dystonic posture and writing speed while writing after the intervention. The writing movement and writing speed scores on a writer's cramp rating scale and writing time decreased. Our findings demonstrated that cathodal tDCS combined with action observation and EMG biofeedback training might improve dystonic writing movements in a writer's cramp patient.

Can Postural Instability Respond to Galvanic Vestibular Stimulation in Patients with Parkinson’s Disease?

Hiroshi Kataoka,Yohei Okada,Takao Kiriyama,Yorihiro Kita,Junji Nakamura,Shu Morioka,Koji Shomoto,Satoshi Ueno 대한파킨슨병및이상운동질환학회 2016 Journal Of Movement Disorders Vol.9 No.1

Objective Galvanic vestibular stimulation (GVS) activates the vestibular afferents, and these changes in vestibular input exert a strong influence on the subject’s posture or standing balance. In patients with Parkinson’s disease (PD), vestibular dysfunction might contribute to postural instability and gait disorders. Methods Current intensity was increased to 0.7 mA, and the current was applied to the patients for 20 minutes. To perform a sham stimulation, the current intensity was increased as described and then decreased to 0 mA over the course of 10 seconds. The patient’s status was recorded continuously for 20 minutes with the patient in the supine position. Results Three out of 5 patients diagnosed with PD with postural instability and/or abnormal axial posture showed a reduction in postural instability after GVS. The score for item 12 of the revised Unified Parkinson’s Disease Rating Scale part 3 was decreased in these patients. Conclusions The mechanism of postural instability is complex and not completely understood. In 2 out of the 5 patients, postural instability was not changed in response to GVS. Nonetheless, the GVS-induced change in postural instability for 3 patients in our study suggests that GVS might be a therapeutic option for postural instability

Influence of mesiodens on adjacent teeth and the timing of its safe removal

Barham Majd,Okada Shunsuke,Hisatomi Miki,Khasawneh Abdullah,Tekiki Nouha,Takeshita Yohei,Kawazu Toshiyuki,Fujita Mariko,Yanagi Yoshinobu,Asaumi Junichi 대한영상치의학회 2022 Imaging Science in Dentistry Vol.52 No.1

Purpose: To focus on the effects of the presence of mesiodens on adjacent teeth and to investigate the timing of its safe removal. Materials and Methods: Cone-beam computed tomography examinations, obtained at Okayama University Hospital over a three-year period, were inspected. Data were recorded including the number of mesiodens; associated abnormalities; and the relationship with neighboring structures. Depending on multiple factors, the risk of developing complications due to early extraction of a mesiodens was divided into three categories: high, medium, and low risk. Results: A total of 5,958 cone-beam computed tomography exams were obtained, 460 patients aged 3-85 years were diagnosed with a total of 568 mesiodens, 382 (67.3%) of which were discovered in young patients (age <10 years), and 333 (87.2%) of these were associated with abnormalities. Regarding the risk categories, 11 (1.9%) were considered to be in the high-risk, five (0.9%) in the medium-risk and 552 (97.2%) in the low-risk categories. Moreover, eight out of 11 high-risk mesiodens were extracted and no post-operative complications have been seen. Conclusion: As the results showed that no postoperative complications were seen in all the extracted cases of high- risk mesiodens, this indicates the possibility of safe extraction at an early age which could reduce related future complications.

Fourth molar: A retrospective study and literature review of a rare clinical entity

Babatunde O. Bamgbose,Shunsuke Okada,Miki Hisatomi,Yoshinobu Yanagi,Yohei Takeshita,Zahrau Saleh Abdu,Edugie J. Ekuase,Junichi Asaumi 대한영상치의학회 2019 Imaging Science in Dentistry Vol.49 No.1

Purpose: The prevalence of supernumerary teeth has been reported to be between 0.1% and 3.8%. The aim of this study was to determine the prevalence, clinical significance, and associated pathologies of fourth molars based on a retrospective study and a literature review. Materials and Methods: A 5-year retrospective prevalence study was conducted at the Department of Oral Diagnosis and Dentomaxillofacial Radiology of Okayama University Hospital, Okayama, Japan. The study involved extracting data from the digital records of patients from January 1, 2013 through December 31, 2017. The sampling frame included all patients who had panoramic radiographs, cone-beam computed tomography (CT), and multislice CT images during the period under review. Results: A total of 26,721 cases were reviewed and 87 fourth molars were identified. The prevalence of fourth molars in the 5-year study at Okayama was calculated as 0.32%. The mean age of patients with a fourth molar was 30.43 years, and the male-to-female ratio was 1:0.98. The vast majority of cases were in the maxilla (92%) and had normal shapes (89.7%); furthermore, 82.8% of cases were unerupted. Conclusion: The prevalence of fourth molars in the study population was found to be 0.32%, and fourth molars occurred with approximately equal frequency in males and females. Fourth molars were more common in the maxilla and were predominantly unerupted and small.

Fourth molar: A retrospective study and literature review of a rare clinical entity

Bamgbose, Babatunde O.,Okada, Shunsuke,Hisatomi, Miki,Yanagi, Yoshinobu,Takeshita, Yohei,Abdu, Zahrau Saleh,Ekuase, Edugie J.,Asaumi, Jun-ichi Korean Academy of Oral and Maxillofacial Radiology 2019 Imaging Science in Dentistry Vol.49 No.1

Purpose: The prevalence of supernumerary teeth has been reported to be between 0.1% and 3.8%. The aim of this study was to determine the prevalence, clinical significance, and associated pathologies of fourth molars based on a retrospective study and a literature review. Materials and Methods: A 5-year retrospective prevalence study was conducted at the Department of Oral Diagnosis and Dentomaxillofacial Radiology of Okayama University Hospital, Okayama, Japan. The study involved extracting data from the digital records of patients from January 1, 2013 through December 31, 2017. The sampling frame included all patients who had panoramic radiographs, cone-beam computed tomography (CT), and multislice CT images during the period under review. Results: A total of 26,721 cases were reviewed and 87 fourth molars were identified. The prevalence of fourth molars in the 5-year study at Okayama was calculated as 0.32%. The mean age of patients with a fourth molar was 30.43 years, and the male-to-female ratio was 1:0.98. The vast majority of cases were in the maxilla (92%) and had normal shapes(89.7%); furthermore, 82.8% of cases were unerupted. Conclusion: The prevalence of fourth molars in the study population was found to be 0.32%, and fourth molars occurred with approximately equal frequency in males and females. Fourth molars were more common in the maxilla and were predominantly unerupted and small.

Open-Chamber Co-Culture Microdevices for Single-Cell Analysis of Skeletal Muscle Myotubes and Motor Neurons with Neuromuscular Junctions

Nao Yamaoka,Kazunori Shimizu,Yu Imaizumi,Yohei Okada,Hiroyuki Honda 한국바이오칩학회 2019 BioChip Journal Vol.13 No.2

Degeneration of motor neurons and skeletal muscles or the collapse of neuromuscular junctions (NMJs) causes progressive motility disturbances in many neuromuscular diseases. Although various microdevices for the co-culture of skeletal muscle myotubes and motor neurons have been developed to investigate neuromuscular diseases in vitro, it remains difficult to isolate single myotubes and motor neurons from the device for single-cell analyses, such as gene expression analysis. Here, we developed open chamber-coculture microdevices that contain cell culture chambers with narrow widths. Given the small chamber width (0.2 mm), the device significantly prevented the overlap among myotubes within the chamber. The percentage of non-overlapping was 95.6 ± 7.7% for the 0.2-mmwidth chamber and 11.8 ± 6.4% for the 7-mm-width chamber as a control. In addition, the device with the 0.2-mm chamber promoted myotube maturation, as indicated by the longer widths and lengths of the myotubes relative to those in the control chamber. Single C2C12 myotubes and human induced pluripotent stem cell (hiPSC)-derived motor neurons were successfully collected from the device with the 0.2-mm chamber using a micromanipulator equipped with a glass capillary. Furthermore, myotubes and hiPSC-derived motor neurons were co-cultured in the device with the 0.2- mm chamber, and the formation of NMJs were observed. Thus, the developed device is a useful tool for performing single-cell analysis for studying neuromuscular diseases in vitro.

Unveiling the Impact of Outpatient Physiotherapy on Specific Motor Symptoms in Parkinson’s Disease: A Prospective Cohort Study

Terasawa Yuta,Ikuno Koki,Fujii Shintaro,Nishi Yuki,Tanizawa Emi,Nabeshima Sachio,Okada Yohei 대한뇌신경재활학회 2023 뇌신경재활 Vol.16 No.3

Understanding how outpatient physiotherapy impacts on specific motor symptoms in Parkinson's disease (PD) is important for multidisciplinary care, but these points have not been clarified. We investigated the impact of outpatient physiotherapy on individual motor symptoms in PD patients. Fifty-five PD patients participated in the prospective cohort study, which examined the changes in motor symptoms after 90 min of outpatient physiotherapy program (1×/week for 10 weeks) and at 3 months follow-up. Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) motor score and tremor, rigidity, bradykinesia, and axial scores were assessed and compared pre-intervention, post-intervention, and at follow-up. Significant level was set at 0.05. Their MDS-UPDRS motor score and axial score significantly decreased post-intervention and at the follow-up. In the analysis differentiating effects based on the severity of motor symptoms according to the MDS-UPDRS motor score, only the moderate-severe group showed significant decreases in their MDS-UPDRS motor score, bradykinesia, and axial scores post-intervention, as well as in their MDS-UPDRS motor score, rigidity, bradykinesia, and axial scores at the follow-up. These findings suggest the outpatient physiotherapy might provide benefits, particularly in managing axial symptoms and bradykinesia, for community dwelling PD patients with moderate-severe motor symptoms within a multidisciplinary care framework.