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Howard Chizeck

University of Washington, Electrical Engineering, Faculty Member

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Sorbonne University

University of Washington

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São Paulo State University

University of Genova

Milovan Radulovic

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Papers by Howard Chizeck

Stochastic stability properties of jump linear systems

by Howard Chizeck and Kenneth A Loparo

IEEE Transactions on Automatic Control, 1992

... Xiangbo Feng, Member, IEEE, Kenneth A. Loparo, Senior Member, IEEE, Yuandong Ji, Member, IEEE... more

Linear quadratic control of a loaded agonist-antagonist muscle pair

IEEE Transactions on Biomedical Engineering, 1987

A discrete-time control law which gives the optimal applied force for a given position trajectory... more A discrete-time control law which gives the optimal applied force for a given position trajectory of a linear second-order external load is computed using linear quadratic regulator (LQR) theory. This control law is used with an existing first-order fixed interpulse interval (IPI) muscle force controller to regulate position in a simulated electrically stimulated loaded agonist-antagonist muscle system. Both force and position feedback are required to implement the control strategy. A nonlinear second-order model of a predominantly slow twitch muscle is used in the simulation. The results suggest that good position control of a loaded antagonist-agonist muscle system is possible if a linear model of the external load is appropriate.

Relationship between intracranial and sagittal sinus pressure in normal and hydrocephalic dogs

Pediatric Neuroscience, 1988

The relationship between intracranial and sagittal sinus pressure in normal and kaolin-induced hy... more The relationship between intracranial and sagittal sinus pressure in normal and kaolin-induced hydrocephalic greyhounds was examined. In normal dogs there was an average 14 mm Hg pressure difference between the ventricles and the sagittal sinus. Elevations of intraventricular pressure were accompanied by small but consistent elevations in sagittal sinus pressure. In hydrocephalic dogs the average pressure differential was only 2 mm Hg. Also elevations of intraventricular pressure were accompanied by greater elevations in sagittal sinus pressures than those seen in normal dogs. The volume-buffering capacity of the sagittal sinus was decreased, and sinography revealed filling of unusual venous collaterals in hydrocephalic dogs--both suggesting an increased resistance to outflow in the sagittal sinus.

Abstract KALMAN FILTERING WITH STATISTICAL STATE CONSTRAINTS

For linear dynamic systems with white process and measurement noise, the Kalman ¯lter is known to... more For linear dynamic systems with white process and measurement noise, the Kalman ¯lter is known to be the minimum variance linear state estimator. In the case that the random quantities are Gaussian, then the Kalman ¯lter is the minimim variance state estimator. However, in the appli-cation of Kalman ¯lters known signal information is often either ignored or dealt with heuristically. For instance, state variable constraints (which may be based on physical considerations) are often neglected because they do not ¯t easily into the structure of the optimal ¯lter. Previous work by the authors demonstrated an analytic method of incorporating deterministic state equality constraints in the Kalman ¯lter. This paper extends that work to develop the properties of Kalman ¯lters in the presence of statistical state constraints. That is, given a linear system such that the expected values of the state variables satisfy some linear equality, we can constrain the Kalman ¯lter estimates to sat-1 is...

Fully implanted adaptive deep brain stimulation in freely moving essential tremor patients

Objective: Deep brain stimulation (DBS) is a safe and established treatment for essential tremor ... more Objective: Deep brain stimulation (DBS) is a safe and established treatment for essential tremor (ET) and several other movement disorders. One approach to improving DBS therapy is adaptive DBS (aDBS), in which stimulation parameters are modulated in real time based on biofeedback from either external or implanted sensors. Previously tested systems have fallen short of translational applicability due to the requirement for patients to continuously wear the necessary sensors or processing devices, as well as privacy and security concerns. Approach: We designed and implemented a translation-ready training data collection system for fully implanted aDBS. Two patients chronically implanted with electrocorticography strips over the hand portion of M1 and DBS probes in the ipsilateral ventral intermediate nucleus of the thalamus for treatment of ET were recruited for this study. Training was conducted using a translation-ready distributed training procedure, allowing a substantially highe...

Your signature is your password: Haptic Passwords on Mobile Devices

ArXiv, 2020

In this paper, a new behavioral biometric password based on haptic interaction is described. This... more In this paper, a new behavioral biometric password based on haptic interaction is described. This "haptic password" system is built on a device that has a force-sensitive screen. The user authentication process leverages maximal overlap discrete wavelet transform (MODWT) based feature extraction along with a customized classifier as well as an adaptive template scheme to accommodate users' variations over time. An experimental study was conducted with 29 subjects and we investigated the authentication performance with multiple user postures under simulated forgery attacks. The performance of the model is evaluated based on authentication accuracies. The results suggest that this proposed haptic password system achieves robust high authentication accuracy and scalability, as well as forgery-proof performance.

Simulation of Bipedal Walking

A 3-dimensional computer model of sustainedbipedal walking is presented. It is intended be used a... more A 3-dimensional computer model of sustainedbipedal walking is presented. It is intended be used as adevelopment tool for walking controllers. The directdynamic simulation has 8 segments, 19 degrees offreedom and is driven by prescribed joint moment andstiffness trajectories. Limited feedback in the form of aproportional-derivative controller provides upper bodystability and allows walking to be sustained indefinitely.The joint moment and stiffness trajectories are specifiedin coarse block segments. By changing the intensity of hipextensor activity during terminal stance the walking stridelength is modulated.

The Physiome Projects and Multiscale Modeling [Life sciences]

The Physiome Projects are a diverse set of scientifically independent projects addressing integra... more The Physiome Projects are a diverse set of scientifically independent projects addressing integrative systems physiology and biology, conducted by individual investigators and teams from different countries. The emphasis in these projects is on medically related physiology and pharmacology. They gather modeling work, information processing methods and tools, databases, and other resources and make them available to a large research community. Their name comes from the physiome, which is defined as the quantitative description of the functional behavior of a living organism. Because the physiome spans the scales of anatomy from gene to whole organism, from bacteria to man, and covers a time scale from embryogenesis to senescence and death (i.e., minutes for bacteria and a century for a few of Earth's creatures), the goal of obtaining the physiome even for a single species is extremely ambitious and unrealizable in the near term. Nevertheless, it provides a definition for integrative efforts and a setting for strategizing and collaborating in science. In this article, we present an overview of the status, accomplishments, and challenges of the Physiome Projects and outline the role played by multiscale modeling.

Orthoses and electrical stimulation for walking in complete paraplegia

Identification of electrically stimulated quadriceps muscles in paraplegic subjects

This work establishes a method for the noninvasive in vivo identification of parametric models of... more This work establishes a method for the noninvasive in vivo identification of parametric models of electrically stimulated muscle in paralyzed individuals, when significant inertial loads and/or load transitions are present. The method used differs from earlier work, in that both the pulse width and stimulus period (interpulse interval) modulation are considered. A Hill-type time series model, in which the output is the product of two factors (activation and torque-angle) is used. In this coupled model, the activation dynamics depend upon velocity. Sequential nonlinear least squares methods are used in the parameter identification. The ability of the model, using identified time-varying parameters, to accurately predict muscle torque outputs is evaluated, along with the variability of the identified parameters. This technique can be used to determine muscle parameter models for biomechanical computer simulations, and for real-time adaptive control and monitoring of muscle response variations such as fatigue.

Telerobotic Control in Virtual Reality

OCEANS 2019 MTS/IEEE SEATTLE

and the Navy have identified more than 400 underwater sites potentially contaminated with munitio... more and the Navy have identified more than 400 underwater sites potentially contaminated with munitions [22]. These munitions were left as a result of past military activities. They are an explosive hazard and their contents pose an environmental risk. An effective ROS (Robot Operating System) package that interfaces with Simulink/Matlab was developed to teleoperate an underwater robotic system in Virtual Reality for the remediation of these munitions. The key advantage of this VR teleoperation method is more effective and intuitive control in comparison to teleoperation methods that utilize a 2D monitor and joystick/keyboard/manipulandum input device. The ROS package was built to work with the Oculus DK2 VR headset and the Razer TM Hydra hand controllers.

Etiology of ventriculomegaly in choroid plexus papilloma

In order to test the hypothesis that overproduction of cerebrospinal fluid can cause the hydrocep... more In order to test the hypothesis that overproduction of cerebrospinal fluid can cause the hydrocephalus seen in choroid plexus papillomas, adult mongrel dogs with and without hydrocephalus were subjected to high pressure intraventricular infusions of artificial cerebrospinal fluid (CSF). Pre- and postinfusion volumes were calculated, using a new method for on-line measurement of ventricular volume involving linear measurements from Conray ventriculograms. Ventricular volumes increased an average of 8% in 36 h. The dogs previously made hydrocephalic by the intracisternal injection of kaolin had a significant volume increase (34% in 36 h). Overproduction of CSF alone can produce hydrocephalus, but the presence of hydrocephalus in choroid plexus papillomas is more likely to be a result of the complex interaction of CSF overproduction and partial restriction of CSF flow.

Proceedings of the Sixth Deep Brain Stimulation Think Tank Modulation of Brain Networks and Application of Advanced Neuroimaging, Neurophysiology, and Optogenetics

Frontiers in Neuroscience

Proceedings of the Sixth Deep Brain Stimulation Think Tank Modulation of Brain Networks and Application of Advanced Neuroimaging, Neurophysiology, and Optogenetics

Frontiers in Neuroscience

Proceedings of the Sixth Deep Brain Stimulation Think Tank Modulation of Brain Networks and Application of Advanced Neuroimaging, Neurophysiology, and Optogenetics

Frontiers in Neuroscience

Motor cortical decoding performance depends on controlled system order

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2014

Recent advances in intracortical brain-machine interfaces (BMIs) for position control have levera... more Recent advances in intracortical brain-machine interfaces (BMIs) for position control have leveraged state estimators to decode intended movements from cortical activity. We revisit the underlying assumptions behind the use of Kalman filters in this context, focusing on the fact that identified cortical coding models capture closed-loop task dynamics. We show that closed-loop models can be partitioned, exposing feedback policies of the brain which are separate from interface and task dynamics. Changing task dynamics may cause the brain to change its control policy, and consequently the closed-loop dynamics. This may degrade performance of decoders upon switching from manual tasks to velocity-controlled BMImediated tasks. We provide experimental results showing that for the same manual cursor task, changing system order affects neural coding of movement. In one experimental condition force determines position directly, and in the other force determines cursor velocity. From this we d...

On the existence of a lactate threshold during incremental exercise: a systems analysis

Journal of Applied Physiology

The relationship between blood lactate concentration ([La]) and O2 uptake (VO2) during incrementa... more The relationship between blood lactate concentration ([La]) and O2 uptake (VO2) during incremental exercise remains controversial: does [La] increase smoothly as a function of VO2 (continuous model), or does it begin to increase abruptly above a particular metabolic rate (threshold model)? The dynamic characteristics of the underlying physiological system are investigated using system identification analysis techniques. A multivariate deterministic time series model of the [La] and VO2 response to incremental changes in work rate was fitted to simulated and experimental data. Time-varying system response parameters were determined through the application of a weighted recursive least squares algorithm. The model, using the identified time-varying parameters, provided a good fit to the data. The variation of these parameters over time was then examined. Two major transitions in the parameters were found to occur at intensity levels equivalent to 53 +/- 8% and 77 +/- 9% maximal VO2 (e...

Automated Control of Drug Infusion

IFAC Proceedings Volumes

Cortical brain computer interface for closed-loop deep brain stimulation

IEEE transactions on neural systems and rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society, Jan 18, 2017

Essential Tremor is the most common neurological movement disorder. This progressive disease caus... more Essential Tremor is the most common neurological movement disorder. This progressive disease causes uncontrollable rhythmic motions-most often affecting the patient's dominant upper extremity-that occur during volitional movement and make it difficult for the patient to perform everyday tasks. Medication may also become ineffective as the disorder progresses. For many patients, deep brain stimulation (DBS) of the thalamus is an effective means of treating this condition when medication fails. In current use, however, clinicians set the patient's stimulator to apply stimulation at all times-whether it is needed or not. This practice leads to excess power use, and more rapid depletion of batteries that require surgical replacement. In the work described here, for the first time, neural sensing of movement (using chronically-implanted cortical electrodes) is used to enable or disable stimulation for tremor. Therapeutic stimulation is delivered only when the patient is actively ...

Proceedings of the Fourth Annual Deep Brain Stimulation Think Tank: A Review of Emerging Issues and Technologies

Frontiers in integrative neuroscience, 2016

This paper provides an overview of current progress in the technological advances and the use of ... more This paper provides an overview of current progress in the technological advances and the use of deep brain stimulation (DBS) to treat neurological and neuropsychiatric disorders, as presented by participants of the Fourth Annual DBS Think Tank, which was convened in March 2016 in conjunction with the Center for Movement Disorders and Neurorestoration at the University of Florida, Gainesveille FL, USA. The Think Tank discussions first focused on policy and advocacy in DBS research and clinical practice, formation of registries, and issues involving the use of DBS in the treatment of Tourette Syndrome. Next, advances in the use of neuroimaging and electrochemical markers to enhance DBS specificity were addressed. Updates on ongoing use and developments of DBS for the treatment of Parkinson's disease, essential tremor, Alzheimer's disease, depression, post-traumatic stress disorder, obesity, addiction were presented, and progress toward innovation(s) in closed-loop application...

Stochastic stability properties of jump linear systems

by Howard Chizeck and Kenneth A Loparo

IEEE Transactions on Automatic Control, 1992

... Xiangbo Feng, Member, IEEE, Kenneth A. Loparo, Senior Member, IEEE, Yuandong Ji, Member, IEEE... more

Linear quadratic control of a loaded agonist-antagonist muscle pair

IEEE Transactions on Biomedical Engineering, 1987

A discrete-time control law which gives the optimal applied force for a given position trajectory... more A discrete-time control law which gives the optimal applied force for a given position trajectory of a linear second-order external load is computed using linear quadratic regulator (LQR) theory. This control law is used with an existing first-order fixed interpulse interval (IPI) muscle force controller to regulate position in a simulated electrically stimulated loaded agonist-antagonist muscle system. Both force and position feedback are required to implement the control strategy. A nonlinear second-order model of a predominantly slow twitch muscle is used in the simulation. The results suggest that good position control of a loaded antagonist-agonist muscle system is possible if a linear model of the external load is appropriate.

Relationship between intracranial and sagittal sinus pressure in normal and hydrocephalic dogs

Pediatric Neuroscience, 1988

The relationship between intracranial and sagittal sinus pressure in normal and kaolin-induced hy... more The relationship between intracranial and sagittal sinus pressure in normal and kaolin-induced hydrocephalic greyhounds was examined. In normal dogs there was an average 14 mm Hg pressure difference between the ventricles and the sagittal sinus. Elevations of intraventricular pressure were accompanied by small but consistent elevations in sagittal sinus pressure. In hydrocephalic dogs the average pressure differential was only 2 mm Hg. Also elevations of intraventricular pressure were accompanied by greater elevations in sagittal sinus pressures than those seen in normal dogs. The volume-buffering capacity of the sagittal sinus was decreased, and sinography revealed filling of unusual venous collaterals in hydrocephalic dogs--both suggesting an increased resistance to outflow in the sagittal sinus.

Abstract KALMAN FILTERING WITH STATISTICAL STATE CONSTRAINTS

For linear dynamic systems with white process and measurement noise, the Kalman ¯lter is known to... more For linear dynamic systems with white process and measurement noise, the Kalman ¯lter is known to be the minimum variance linear state estimator. In the case that the random quantities are Gaussian, then the Kalman ¯lter is the minimim variance state estimator. However, in the appli-cation of Kalman ¯lters known signal information is often either ignored or dealt with heuristically. For instance, state variable constraints (which may be based on physical considerations) are often neglected because they do not ¯t easily into the structure of the optimal ¯lter. Previous work by the authors demonstrated an analytic method of incorporating deterministic state equality constraints in the Kalman ¯lter. This paper extends that work to develop the properties of Kalman ¯lters in the presence of statistical state constraints. That is, given a linear system such that the expected values of the state variables satisfy some linear equality, we can constrain the Kalman ¯lter estimates to sat-1 is...

Fully implanted adaptive deep brain stimulation in freely moving essential tremor patients

Objective: Deep brain stimulation (DBS) is a safe and established treatment for essential tremor ... more Objective: Deep brain stimulation (DBS) is a safe and established treatment for essential tremor (ET) and several other movement disorders. One approach to improving DBS therapy is adaptive DBS (aDBS), in which stimulation parameters are modulated in real time based on biofeedback from either external or implanted sensors. Previously tested systems have fallen short of translational applicability due to the requirement for patients to continuously wear the necessary sensors or processing devices, as well as privacy and security concerns. Approach: We designed and implemented a translation-ready training data collection system for fully implanted aDBS. Two patients chronically implanted with electrocorticography strips over the hand portion of M1 and DBS probes in the ipsilateral ventral intermediate nucleus of the thalamus for treatment of ET were recruited for this study. Training was conducted using a translation-ready distributed training procedure, allowing a substantially highe...

Your signature is your password: Haptic Passwords on Mobile Devices

ArXiv, 2020

In this paper, a new behavioral biometric password based on haptic interaction is described. This... more In this paper, a new behavioral biometric password based on haptic interaction is described. This "haptic password" system is built on a device that has a force-sensitive screen. The user authentication process leverages maximal overlap discrete wavelet transform (MODWT) based feature extraction along with a customized classifier as well as an adaptive template scheme to accommodate users' variations over time. An experimental study was conducted with 29 subjects and we investigated the authentication performance with multiple user postures under simulated forgery attacks. The performance of the model is evaluated based on authentication accuracies. The results suggest that this proposed haptic password system achieves robust high authentication accuracy and scalability, as well as forgery-proof performance.

Simulation of Bipedal Walking

A 3-dimensional computer model of sustainedbipedal walking is presented. It is intended be used a... more A 3-dimensional computer model of sustainedbipedal walking is presented. It is intended be used as adevelopment tool for walking controllers. The directdynamic simulation has 8 segments, 19 degrees offreedom and is driven by prescribed joint moment andstiffness trajectories. Limited feedback in the form of aproportional-derivative controller provides upper bodystability and allows walking to be sustained indefinitely.The joint moment and stiffness trajectories are specifiedin coarse block segments. By changing the intensity of hipextensor activity during terminal stance the walking stridelength is modulated.

The Physiome Projects and Multiscale Modeling [Life sciences]

The Physiome Projects are a diverse set of scientifically independent projects addressing integra... more The Physiome Projects are a diverse set of scientifically independent projects addressing integrative systems physiology and biology, conducted by individual investigators and teams from different countries. The emphasis in these projects is on medically related physiology and pharmacology. They gather modeling work, information processing methods and tools, databases, and other resources and make them available to a large research community. Their name comes from the physiome, which is defined as the quantitative description of the functional behavior of a living organism. Because the physiome spans the scales of anatomy from gene to whole organism, from bacteria to man, and covers a time scale from embryogenesis to senescence and death (i.e., minutes for bacteria and a century for a few of Earth's creatures), the goal of obtaining the physiome even for a single species is extremely ambitious and unrealizable in the near term. Nevertheless, it provides a definition for integrative efforts and a setting for strategizing and collaborating in science. In this article, we present an overview of the status, accomplishments, and challenges of the Physiome Projects and outline the role played by multiscale modeling.

Orthoses and electrical stimulation for walking in complete paraplegia

Identification of electrically stimulated quadriceps muscles in paraplegic subjects

This work establishes a method for the noninvasive in vivo identification of parametric models of... more This work establishes a method for the noninvasive in vivo identification of parametric models of electrically stimulated muscle in paralyzed individuals, when significant inertial loads and/or load transitions are present. The method used differs from earlier work, in that both the pulse width and stimulus period (interpulse interval) modulation are considered. A Hill-type time series model, in which the output is the product of two factors (activation and torque-angle) is used. In this coupled model, the activation dynamics depend upon velocity. Sequential nonlinear least squares methods are used in the parameter identification. The ability of the model, using identified time-varying parameters, to accurately predict muscle torque outputs is evaluated, along with the variability of the identified parameters. This technique can be used to determine muscle parameter models for biomechanical computer simulations, and for real-time adaptive control and monitoring of muscle response variations such as fatigue.

Telerobotic Control in Virtual Reality

OCEANS 2019 MTS/IEEE SEATTLE

and the Navy have identified more than 400 underwater sites potentially contaminated with munitio... more and the Navy have identified more than 400 underwater sites potentially contaminated with munitions [22]. These munitions were left as a result of past military activities. They are an explosive hazard and their contents pose an environmental risk. An effective ROS (Robot Operating System) package that interfaces with Simulink/Matlab was developed to teleoperate an underwater robotic system in Virtual Reality for the remediation of these munitions. The key advantage of this VR teleoperation method is more effective and intuitive control in comparison to teleoperation methods that utilize a 2D monitor and joystick/keyboard/manipulandum input device. The ROS package was built to work with the Oculus DK2 VR headset and the Razer TM Hydra hand controllers.

Etiology of ventriculomegaly in choroid plexus papilloma

In order to test the hypothesis that overproduction of cerebrospinal fluid can cause the hydrocep... more In order to test the hypothesis that overproduction of cerebrospinal fluid can cause the hydrocephalus seen in choroid plexus papillomas, adult mongrel dogs with and without hydrocephalus were subjected to high pressure intraventricular infusions of artificial cerebrospinal fluid (CSF). Pre- and postinfusion volumes were calculated, using a new method for on-line measurement of ventricular volume involving linear measurements from Conray ventriculograms. Ventricular volumes increased an average of 8% in 36 h. The dogs previously made hydrocephalic by the intracisternal injection of kaolin had a significant volume increase (34% in 36 h). Overproduction of CSF alone can produce hydrocephalus, but the presence of hydrocephalus in choroid plexus papillomas is more likely to be a result of the complex interaction of CSF overproduction and partial restriction of CSF flow.

Proceedings of the Sixth Deep Brain Stimulation Think Tank Modulation of Brain Networks and Application of Advanced Neuroimaging, Neurophysiology, and Optogenetics

Frontiers in Neuroscience

Proceedings of the Sixth Deep Brain Stimulation Think Tank Modulation of Brain Networks and Application of Advanced Neuroimaging, Neurophysiology, and Optogenetics

Frontiers in Neuroscience

Proceedings of the Sixth Deep Brain Stimulation Think Tank Modulation of Brain Networks and Application of Advanced Neuroimaging, Neurophysiology, and Optogenetics

Frontiers in Neuroscience

Motor cortical decoding performance depends on controlled system order

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2014

Recent advances in intracortical brain-machine interfaces (BMIs) for position control have levera... more Recent advances in intracortical brain-machine interfaces (BMIs) for position control have leveraged state estimators to decode intended movements from cortical activity. We revisit the underlying assumptions behind the use of Kalman filters in this context, focusing on the fact that identified cortical coding models capture closed-loop task dynamics. We show that closed-loop models can be partitioned, exposing feedback policies of the brain which are separate from interface and task dynamics. Changing task dynamics may cause the brain to change its control policy, and consequently the closed-loop dynamics. This may degrade performance of decoders upon switching from manual tasks to velocity-controlled BMImediated tasks. We provide experimental results showing that for the same manual cursor task, changing system order affects neural coding of movement. In one experimental condition force determines position directly, and in the other force determines cursor velocity. From this we d...

On the existence of a lactate threshold during incremental exercise: a systems analysis

Journal of Applied Physiology

The relationship between blood lactate concentration ([La]) and O2 uptake (VO2) during incrementa... more The relationship between blood lactate concentration ([La]) and O2 uptake (VO2) during incremental exercise remains controversial: does [La] increase smoothly as a function of VO2 (continuous model), or does it begin to increase abruptly above a particular metabolic rate (threshold model)? The dynamic characteristics of the underlying physiological system are investigated using system identification analysis techniques. A multivariate deterministic time series model of the [La] and VO2 response to incremental changes in work rate was fitted to simulated and experimental data. Time-varying system response parameters were determined through the application of a weighted recursive least squares algorithm. The model, using the identified time-varying parameters, provided a good fit to the data. The variation of these parameters over time was then examined. Two major transitions in the parameters were found to occur at intensity levels equivalent to 53 +/- 8% and 77 +/- 9% maximal VO2 (e...

Automated Control of Drug Infusion

IFAC Proceedings Volumes

Cortical brain computer interface for closed-loop deep brain stimulation

IEEE transactions on neural systems and rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society, Jan 18, 2017

Essential Tremor is the most common neurological movement disorder. This progressive disease caus... more Essential Tremor is the most common neurological movement disorder. This progressive disease causes uncontrollable rhythmic motions-most often affecting the patient's dominant upper extremity-that occur during volitional movement and make it difficult for the patient to perform everyday tasks. Medication may also become ineffective as the disorder progresses. For many patients, deep brain stimulation (DBS) of the thalamus is an effective means of treating this condition when medication fails. In current use, however, clinicians set the patient's stimulator to apply stimulation at all times-whether it is needed or not. This practice leads to excess power use, and more rapid depletion of batteries that require surgical replacement. In the work described here, for the first time, neural sensing of movement (using chronically-implanted cortical electrodes) is used to enable or disable stimulation for tremor. Therapeutic stimulation is delivered only when the patient is actively ...

Proceedings of the Fourth Annual Deep Brain Stimulation Think Tank: A Review of Emerging Issues and Technologies

Frontiers in integrative neuroscience, 2016

This paper provides an overview of current progress in the technological advances and the use of ... more This paper provides an overview of current progress in the technological advances and the use of deep brain stimulation (DBS) to treat neurological and neuropsychiatric disorders, as presented by participants of the Fourth Annual DBS Think Tank, which was convened in March 2016 in conjunction with the Center for Movement Disorders and Neurorestoration at the University of Florida, Gainesveille FL, USA. The Think Tank discussions first focused on policy and advocacy in DBS research and clinical practice, formation of registries, and issues involving the use of DBS in the treatment of Tourette Syndrome. Next, advances in the use of neuroimaging and electrochemical markers to enhance DBS specificity were addressed. Updates on ongoing use and developments of DBS for the treatment of Parkinson's disease, essential tremor, Alzheimer's disease, depression, post-traumatic stress disorder, obesity, addiction were presented, and progress toward innovation(s) in closed-loop application...