Interactions between the neural and musculoskeletal systems are a prerequisite for the production of robust movement. In spite of this, the neural control and musculoskeletal structure underlying biological movements are typically studied independently, with little attention paid to how changes in one may affect the other. Understanding these interactions may be critical to improving current rehabilitation technologies and therapy methods. As an example, balance disorders are multifactorial in nature and identifying whether biomechanical or neural changes are the source of instability remains an unanswered question. I have used a combined experimental and modeling approach to understand neural and biomechanical interactions governing human balance control. I developed a simple four-bar linkage model with delayed feedback to investigate frontal-plane standing balance. Using methods from time-delay systems I present evidence from this model that biomechanical structure is important for behavioral function and show that neural control and biomechanical structure co-vary for stable human balance. Predictions from the model were tested experimentally to dissociate the effects of inertia and postural configuration on balance. In addition, I applied robust control methods to solve the difficult problem of comparing the relative performance between neuromechanical systems that differ in parameter values and predicted a common mechanism to explain changes in neural control across biomechanical contexts. In the future, the analytical tools and simulation methods I have developed can be generalized to investigate changes in neuromechanical interactions of various deficits in biomechanics (ACL rupture, amputation) and neural control (Parkinson's disease, stroke). Furthermore, this approach can be used to explain how neural control and biomechanical structure relate to the diversity of animal form and function, as well as suggest biomimetic control policies for robotics.

国立情報学研究所で電子化したコンテンツを使用している。

Thesis (Ph. D.)--University of Sydney, 2001. / Includes tables. Title from title screen (viewed Apr. 22, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Physiotherapy, Faculty of Health Science. Includes bibliography. Also available in print form.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

abstract: Otoacoustic emissions (OAEs) are soft sounds generated by the inner ear and can be recorded within the ear canal. Since OAEs can reflect the functional status of the inner ear, OAE measurements have been widely used for hearing loss screening in the clinic. However, there are limitations in current clinical OAE measurements, such as the restricted frequency range, low efficiency and inaccurate calibration. In this dissertation project, a new method of OAE measurement which used a swept tone to evoke the stimulus frequency OAEs (SFOAEs) was developed to overcome the limitations of current methods. In addition, an in-situ calibration was applied to equalize the spectral level of the swept-tone stimulus at the tympanic membrane (TM). With this method, SFOAEs could be recorded with high resolution over a wide frequency range within one or two minutes. Two experiments were conducted to verify the accuracy of the in-situ calibration and to test the performance of the swept-tone SFOAEs. In experiment I, the calibration of the TM sound pressure was verified in both acoustic cavities and real ears by using a second probe microphone. In addition, the benefits of the in-situ calibration were investigated by measuring OAEs under different calibration conditions. Results showed that the TM pressure could be predicted correctly, and the in-situ calibration provided the most reliable results in OAE measurements. In experiment II, a three-interval paradigm with a tracking-filter technique was used to record the swept-tone SFOAEs in 20 normal-hearing subjects. The test-retest reliability of the swept-tone SFOAEs was examined using a repeated-measure design under various stimulus levels and durations. The accuracy of the swept-tone method was evaluated by comparisons with a standard method using discrete pure tones. Results showed that SFOAEs could be reliably and accurately measured with the swept-tone method. Comparing with the pure-tone approach, the swept-tone method showed significantly improved efficiency. The swept-tone SFOAEs with in-situ calibration may be an alternative of current clinical OAE measurements for more detailed evaluation of inner ear function and accurate diagnosis. / Dissertation/Thesis / Ph.D. Speech and Hearing Science 2012

abstract: Gait and balance disorders are the second leading cause of falls in the elderly. Investigating the changes in static and dynamic balance due to aging may provide a better understanding of the effects of aging on postural control system. Static and dynamic balance were evaluated in a total of 21 young (21-35 years) and 22 elderly (50-75 years) healthy subjects while they performed three different tasks: quiet standing, dynamic weight shifts, and over ground walking. During the quiet standing task, the subjects stood with their eyes open and eyes closed. When performing dynamic weight shifts task, subjects shifted their Center of Pressure (CoP) from the center target to outward targets and vice versa while following real-time feedback of their CoP. For over ground walking tasks, subjects performed Timed Up and Go test, tandem walking, and regular walking at their self-selected speed. Various quantitative balance and gait measures were obtained to evaluate the above respective balance and walking tasks. Total excursion, sway area, and mean frequency of CoP during quiet standing were found to be the most reliable and showed significant increase with age and absence of visual input. During dynamic shifts, elderly subjects exhibited higher initiation time, initiation path length, movement time, movement path length, and inaccuracy indicating deterioration in performance. Furthermore, the elderly walked with a shorter stride length, increased stride variability, with a greater turn and turn-to-sit duration. Significant correlations were also observed between measures derived from the different balance and gait tasks. Thus, it can be concluded that aging deteriorates the postural control system affecting static and dynamic balance and some of the alterations in CoP and gait measures may be considered as protective mechanisms to prevent loss of balance. / Dissertation/Thesis / M.S. Bioengineering 2014

In September 2018 I started my research project at the Master of contemporary circus practices at DOCH, Stockholm. Much has happened since then. 2018 turned into 2021. The school changed its name to SKH. The world turned into a pandemic battle zone. I turned into a mother of two. Little things, big things. Life.The following is a compilation of material from the last 2½ years. It is made like this to provide insight into an unusual process. A research project where the obstacles during the process ended up being the theme of the project.It is structured as followed:Old text material is kept in its original shape, even when it is painful (!) for me to go back and read it. I have shortened some sections and deleted irrelevant parts even though I know that what seems irrelevant today can become relevant tomorrow. Repetitions will likely occur, some on purpose, others not.Old texts taken from school reports are in blue like this. Blue, for me the color of balance. When I balance on my hands, I see myself in and surrounded by blue shades when I maintain balance and in white when I fall.Extracts from a diary written during this writing process are in red like this. Blood red. Written during a lockdown where I felt quite melodramatic hence the color.A script I wrote to my classmates is in green, the color of... hope? Definitely of new life.New reflections are added, some to explain the research further, others to engage in a critical dialogue with my voice of the past. All new thoughts are in black like this. These texts are the narrator of the story, the guide of the exhibition, the detective of the disappeared meaning, the curator of the mess

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18768号 / 理博第4026号 / 新制||理||1580(附属図書館) / 31719 / 京都大学大学院理学研究科数学・数理解析専攻 / (主査)教授 堤 誉志雄, 教授 上田 哲生, 教授 加藤 毅 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

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