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Rolandino G, Gagliardi M, Martins T, Cerone GL, Andrews B, FitzGerald JJ. Developing RPC-Net: Leveraging High-Density Electromyography and Machine Learning for Improved Hand Position Estimation. IEEE Trans Biomed Eng 2024; 71:1617-1627. [PMID: 38133970 DOI: 10.1109/tbme.2023.3346192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
OBJECTIVE The purpose of this study was to develop and evaluate the performance of RPC-Net (Recursive Prosthetic Control Network), a novel method using simple neural network architectures to translate electromyographic activity into hand position with high accuracy and computational efficiency. METHODS RPC-Net uses a regression-based approach to convert forearm electromyographic signals into hand kinematics. We tested the adaptability of the algorithm to different conditions and compared its performance with that of solutions from the academic literature. RESULTS RPC-Net demonstrated a high degree of accuracy in predicting hand position from electromyographic activity, outperforming other solutions with the same computational cost. Including previous position data consistently improved results across subjects and conditions. RPC-Net showed robustness against a reduction in the number of electromyography electrodes used and shorter input signals, indicating potential for further reduction in computational cost. CONCLUSION The results demonstrate that RPC-Net is capable of accurately translating forearm electromyographic activity into hand position, offering a practical and adaptable tool that may be accessible in clinical settings. SIGNIFICANCE The development of RPC-Net represents a significant advancement. In clinical settings, its application could enable prosthetic devices to be controlled in a way that feels more natural, improving the quality of life for individuals with limb loss.
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Manfield J, Thomas S, Bogdanovic M, Sarangmat N, Antoniades C, Green AL, FitzGerald JJ. Seeing Is Believing: Photon Counting Computed Tomography Clearly Images Directional Deep Brain Stimulation Lead Segments and Markers After Implantation. Neuromodulation 2024; 27:557-564. [PMID: 37921733 DOI: 10.1016/j.neurom.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 08/11/2023] [Accepted: 09/12/2023] [Indexed: 11/04/2023]
Abstract
BACKGROUND AND OBJECTIVES Directional deep brain stimulation (DBS) electrodes are increasingly used, but conventional computed tomography (CT) is unable to directly image segmented contacts owing to physics-based resolution constraints. Postoperative electrode segment orientation assessment is necessary because of the possibility of significant deviation during or immediately after insertion. Photon-counting detector (PCD) CT is a relatively novel technology that enables high resolution imaging while addressing several limitations intrinsic to CT. We show how PCD CT can enable clear in vivo imaging of DBS electrodes, including segmented contacts and markers for all major lead manufacturers. MATERIALS AND METHODS We describe postoperative imaging and reconstruction protocols we have developed to enable optimal lead visualization. PCD CT images were obtained of directional leads from the three major manufacturers and fused with preoperative 3T magnetic resonance imaging (MRI). Radiation dosimetry also was evaluated and compared with conventional imaging controls. Orientation estimates from directly imaged leads were compared with validated software-based reconstructions (derived from standard CT imaging artifact analysis) to quantify congruence in alignment and directional orientation. RESULTS High-fidelity images were obtained for 15 patients, clearly indicating the segmented contacts and directional markers both on CT alone and when fused to MRI. Our routine imaging protocol is described. Ionizing radiation doses were significantly lower than with conventional CT. For most leads, the directly imaged lead orientations and depths corresponded closely to those predicted by CT artifact-based reconstructions. However, unlike direct imaging, the software reconstructions were susceptible to 180° error in orientation assessment. CONCLUSIONS High-resolution photon-counting CT can very clearly image segmented DBS electrode contacts and directional markers and unambiguously determine lead orientation, with lower radiation than in conventional imaging. This obviates the need for further imaging and may facilitate anatomically tailored directional programming.
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Affiliation(s)
- James Manfield
- Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - Sheena Thomas
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Marko Bogdanovic
- Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | | | | | - Alexander L Green
- Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK; Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - James J FitzGerald
- Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK; Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.
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Keogh C, Saavedra F, Dubo S, Aqueveque P, Ortega P, Gomez B, Germany E, Pinto D, Osorio R, Pastene F, Poulton A, Jarvis J, Andrews B, FitzGerald JJ. Closed-loop parameter optimization for patient-specific phrenic nerve stimulation. Artif Organs 2024; 48:274-284. [PMID: 37246826 DOI: 10.1111/aor.14593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 05/02/2023] [Accepted: 05/25/2023] [Indexed: 05/30/2023]
Abstract
BACKGROUND Ventilator-induced diaphragm dysfunction occurs rapidly following the onset of mechanical ventilation and has significant clinical consequences. Phrenic nerve stimulation has shown promise in maintaining diaphragm function by inducing diaphragm contractions. Non-invasive stimulation is an attractive option as it minimizes the procedural risks associated with invasive approaches. However, this method is limited by sensitivity to electrode position and inter-individual variability in stimulation thresholds. This makes clinical application challenging due to potentially time-consuming calibration processes to achieve reliable stimulation. METHODS We applied non-invasive electrical stimulation to the phrenic nerve in the neck in healthy volunteers. A closed-loop system recorded the respiratory flow produced by stimulation and automatically adjusted the electrode position and stimulation amplitude based on the respiratory response. By iterating over electrodes, the optimal electrode was selected. A binary search method over stimulation amplitudes was then employed to determine an individualized stimulation threshold. Pulse trains above this threshold were delivered to produce diaphragm contraction. RESULTS Nine healthy volunteers were recruited. Mean threshold stimulation amplitude was 36.17 ± 14.34 mA (range 19.38-59.06 mA). The threshold amplitude for reliable nerve capture was moderately correlated with BMI (Pearson's r = 0.66, p = 0.049). Repeating threshold measurements within subjects demonstrated low intra-subject variability of 2.15 ± 1.61 mA between maximum and minimum thresholds on repeated trials. Bilateral stimulation with individually optimized parameters generated reliable diaphragm contraction, resulting in significant inhaled volumes following stimulation. CONCLUSION We demonstrate the feasibility of a system for automatic optimization of electrode position and stimulation parameters using a closed-loop system. This opens the possibility of easily deployable individualized stimulation in the intensive care setting to reduce ventilator-induced diaphragm dysfunction.
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Affiliation(s)
- Conor Keogh
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Francisco Saavedra
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
- Department of Electrical Engineering, Universidad de Concepcion, Concepcion, Chile
| | - Sebastian Dubo
- Department of Physiotherapy, Universidad de Concepcion, Concepcion, Chile
| | - Pablo Aqueveque
- Department of Electrical Engineering, Universidad de Concepcion, Concepcion, Chile
| | - Paulina Ortega
- Department of Physiotherapy, Universidad de Concepcion, Concepcion, Chile
| | - Britam Gomez
- Department of Electrical Engineering, Universidad de Concepcion, Concepcion, Chile
| | - Enrique Germany
- Department of Electrical Engineering, Universidad de Concepcion, Concepcion, Chile
| | - Daniela Pinto
- Department of Electrical Engineering, Universidad de Concepcion, Concepcion, Chile
| | - Rodrigo Osorio
- Department of Electrical Engineering, Universidad de Concepcion, Concepcion, Chile
| | - Francisco Pastene
- Department of Electrical Engineering, Universidad de Concepcion, Concepcion, Chile
| | - Adrian Poulton
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Jonathan Jarvis
- School of Sports and Exercise Science, Liverpool John Moores University, Liverpool, UK
| | - Brian Andrews
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - James J FitzGerald
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
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Sotirakis C, Su Z, Brzezicki MA, Conway N, Tarassenko L, FitzGerald JJ, Antoniades CA. Identification of motor progression in Parkinson's disease using wearable sensors and machine learning. NPJ Parkinsons Dis 2023; 9:142. [PMID: 37805655 PMCID: PMC10560243 DOI: 10.1038/s41531-023-00581-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 09/20/2023] [Indexed: 10/09/2023] Open
Abstract
Wearable devices offer the potential to track motor symptoms in neurological disorders. Kinematic data used together with machine learning algorithms can accurately identify people living with movement disorders and the severity of their motor symptoms. In this study we aimed to establish whether a combination of wearable sensor data and machine learning algorithms with automatic feature selection can estimate the clinical rating scale and whether it is possible to monitor the motor symptom progression longitudinally, for people with Parkinson's Disease. Seventy-four patients visited the lab seven times at 3-month intervals. Their walking (2-minutes) and postural sway (30-seconds,eyes-closed) were recorded using six Inertial Measurement Unit sensors. Simple linear regression and Random Forest algorithms were utilised together with different routines of automatic feature selection or factorisation, resulting in seven different machine learning algorithms to estimate the clinical rating scale (Movement Disorder Society- Unified Parkinson's Disease Rating Scale part III; MDS-UPDRS-III). Twenty-nine features were found to significantly progress with time at group level. The Random Forest model revealed the most accurate estimation of the MDS-UPDRS-III among the seven models. The model estimations detected a statistically significant progression of the motor symptoms within 15 months when compared to the first visit, whereas the MDS-UPDRS-III did not capture any change. Wearable sensors and machine learning can track the motor symptom progression in people with PD better than the conventionally used clinical rating scales. The methods described in this study can be utilised complimentary to the clinical rating scales to improve the diagnostic and prognostic accuracy.
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Affiliation(s)
- Charalampos Sotirakis
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Zi Su
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Maksymilian A Brzezicki
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Niall Conway
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Lionel Tarassenko
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK
| | - James J FitzGerald
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Chrystalina A Antoniades
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
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Manfield J, Thomas S, Antoniades C, Green AL, FitzGerald JJ. High resolution photon counting CT permits direct visualisation of directional deep brain stimulation lead segments and markers. Brain Stimul 2023; 16:1276-1277. [PMID: 37611658 DOI: 10.1016/j.brs.2023.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 06/29/2023] [Accepted: 08/18/2023] [Indexed: 08/25/2023] Open
Affiliation(s)
- James Manfield
- Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - Sheena Thomas
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Charalambos Antoniades
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Alexander L Green
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK; Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - James J FitzGerald
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK; Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK.
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Brzezicki MA, Conway N, Sotirakis C, FitzGerald JJ, Antoniades CA. Antiparkinsonian medication masks motor signal progression in de novo patients. Heliyon 2023; 9:e16415. [PMID: 37265609 PMCID: PMC10230196 DOI: 10.1016/j.heliyon.2023.e16415] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/17/2023] [Accepted: 05/16/2023] [Indexed: 06/03/2023] Open
Abstract
Patients not yet receiving medication provide insight to drug-naïve early physiology of Parkinson's Disease (PD). Wearable sensors can measure changes in motor features before and after introduction of antiparkinsonian medication. We aimed to identify features of upper limb bradykinesia, postural stability, and gait that measurably progress in de novo PD patients prior to the start of medication, and determine whether these features remain sensitive to progression in the period after commencement of antiparkinsonian medication. Upper limb motion was measured using an inertial sensor worn on a finger, while postural stability and gait were recorded using an array of six wearable sensors. Patients were tested over nine visits at three monthly intervals. The timepoint of start of medication was noted. Three upper limb bradykinetic features (finger tapping speed, pronation supination speed, and pronation supination amplitude) and three gait features (gait speed, arm range of motion, duration of stance phase) were found to progress in unmedicated early-stage PD patients. In all features, progression was masked after the start of medication. Commencing antiparkinsonian medication is known to lead to masking of progression signals in clinical measures in de novo PD patients. In this study, we show that this effect is also observed with digital measures of bradykinetic and gait motor features.
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Affiliation(s)
- Maksymilian A. Brzezicki
- Neurometrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK
| | - Niall Conway
- Neurometrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK
| | - Charalampos Sotirakis
- Neurometrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK
| | - James J. FitzGerald
- Neurometrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Chrystalina A. Antoniades
- Neurometrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK
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Su ZH, Patel S, Gavine B, Buchanan T, Bogdanovic M, Sarangmat N, Green AL, Bloem BR, FitzGerald JJ, Antoniades CA. Deep Brain Stimulation and Levodopa Affect Gait Variability in Parkinson Disease Differently. Neuromodulation 2023; 26:382-393. [PMID: 35562261 DOI: 10.1016/j.neurom.2022.04.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/07/2022] [Accepted: 02/06/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Both dopaminergic medication and subthalamic nucleus (STN) deep brain stimulation (DBS) can improve the amplitude and speed of gait in Parkinson disease (PD), but relatively little is known about their comparative effects on gait variability. Gait irregularity has been linked to the degeneration of cholinergic neurons in the pedunculopontine nucleus (PPN). OBJECTIVES The STN and PPN have reciprocal connections, and we hypothesized that STN DBS might improve gait variability by modulating PPN function. Dopaminergic medication should not do this, and we therefore sought to compare the effects of medication and STN DBS on gait variability. MATERIALS AND METHODS We studied 11 patients with STN DBS systems on and off with no alteration to their medication, and 15 patients with PD without DBS systems on and off medication. Participants walked for two minutes in each state, wearing six inertial measurement units. Variability has previously often been expressed in terms of SD or coefficient of variation over a testing session, but these measures conflate long-term variability (eg, gradual slowing, which is not necessarily pathological) with short-term variability (true irregularity). We used Poincaré analysis to separate the short- and long-term variability. RESULTS DBS decreased short-term variability in lower limb gait parameters, whereas medication did not have this effect. In contrast, STN DBS had no effect on arm swing and trunk motion variability, whereas medication increased them, without obvious dyskinesia. CONCLUSIONS Our results suggest that STN DBS acts through a nondopaminergic mechanism to reduce gait variability. We believe that the most likely explanation is the retrograde activation of cholinergic PPN projection neurons.
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Affiliation(s)
- Zi H Su
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Salil Patel
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Bronwyn Gavine
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - Marko Bogdanovic
- Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | | | - Alexander L Green
- Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK; Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Bastiaan R Bloem
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - James J FitzGerald
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK; Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Chrystalina A Antoniades
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
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Keogh C, FitzGerald JJ. Decomposition into dynamic features reveals a conserved temporal structure in hand kinematics. iScience 2022; 25:105428. [PMID: 36388974 PMCID: PMC9641230 DOI: 10.1016/j.isci.2022.105428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 09/01/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022] Open
Abstract
The human hand is a unique and highly complex effector. The ability to describe hand kinematics with a small number of features suggests that complex hand movements are composed of combinations of simpler movements. This would greatly simplify the neural control of hand movements. If such movement primitives exist, a dimensionality reduction approach designed to exploit these features should outperform existing methods. We developed a deep neural network to capture the temporal dynamics of movements and demonstrate that the features learned allow accurate representation of functional hand movements using lower-dimensional representations than previously reported. We show that these temporal features are highly conserved across individuals and can interpolate previously unseen movements, indicating that they capture the intrinsic structure of hand movements. These results indicate that functional hand movements are defined by a low-dimensional basis set of movement primitives with important temporal dynamics and that these features are common across individuals. Hand movements are comprised of a low-dimensional set of movement primitives Primitive movements have an important temporal component Spatiotemporal movement primitives are conserved across individuals New complex movements can be flexibly reconstructed using these primitives
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Sotirakis C, Conway N, Su Z, Villarroel M, Tarassenko L, FitzGerald JJ, Antoniades CA. Longitudinal Monitoring of Progressive Supranuclear Palsy using Body-Worn Movement Sensors. Mov Disord 2022; 37:2263-2271. [PMID: 36054142 DOI: 10.1002/mds.29194] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 07/15/2022] [Accepted: 07/25/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND We have previously shown that wearable technology and machine learning techniques can accurately discriminate between progressive supranuclear palsy (PSP), Parkinson's disease, and healthy controls. To date these techniques have not been applied in longitudinal studies of disease progression in PSP. OBJECTIVES We aimed to establish whether data collected by a body-worn inertial measurement unit (IMU) network could predict clinical rating scale scores in PSP and whether it could be used to track disease progression. METHODS We studied gait and postural stability in 17 participants with PSP over five visits at 3-month intervals. Participants performed a 2-minute walk and an assessment of postural stability by standing for 30 seconds with their eyes closed, while wearing an array of six IMUs. RESULTS Thirty-two gait and posture features were identified, which progressed significantly with time. A simple linear regression model incorporating the three features with the clearest progression pattern was able to detect statistically significant progression 3 months in advance of the clinical scores. A more complex linear regression and a random forest approach did not improve on this. CONCLUSIONS The reduced variability of the models, in comparison to clinical rating scales, allows a significant change in disease status from baseline to be observed at an earlier stage. The current study sheds light on the individual features that are important in tracking disease progression. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Charalampos Sotirakis
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Niall Conway
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Zi Su
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Mauricio Villarroel
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Lionel Tarassenko
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - James J FitzGerald
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Chrystalina A Antoniades
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
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Su ZH, Patel S, Bredemeyer O, FitzGerald JJ, Antoniades CA. Parkinson’s disease deficits in time perception to auditory as well as visual stimuli – A large online study. Front Neurosci 2022; 16:995438. [DOI: 10.3389/fnins.2022.995438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
Cognitive deficits are common in Parkinson’s disease (PD) and range from mild cognitive impairment to dementia, often dramatically reducing quality of life. Physiological models have shown that attention and memory are predicated on the brain’s ability to process time. Perception has been shown to be increased or decreased by activation or deactivation of dopaminergic neurons respectively. Here we investigate differences in time perception between patients with PD and healthy controls. We have measured differences in sub-second- and second-time intervals. Sensitivity and error in perception as well as the response times are calculated. Additionally, we investigated intra-individual response variability and the effect of participant devices on both reaction time and sensitivity. Patients with PD have impaired sensitivity in discriminating between durations of both visual and auditory stimuli compared to healthy controls. Though initially designed as an in-person study, because of the pandemic the experiment was adapted into an online study. This adaptation provided a unique opportunity to enroll a larger number of international participants and use this study to evaluate the feasibility of future virtual studies focused on cognitive impairment. To our knowledge this is the only time perception study, focusing on PD, which measures the differences in perception using both auditory and visual stimuli. The cohort involved is the largest to date, comprising over 800 participants.
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Keogh C, Saavedra F, Dubo S, Aqueveque P, Ortega P, Gomez B, Germany E, Pinto D, Osorio R, Pastene F, Poulton A, Jarvis J, Andrews B, FitzGerald JJ. Non-invasive phrenic nerve stimulation to avoid ventilator-induced diaphragm dysfunction in critical care. Artif Organs 2022; 46:1988-1997. [PMID: 35377472 PMCID: PMC9790411 DOI: 10.1111/aor.14244] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/09/2022] [Accepted: 03/16/2022] [Indexed: 12/30/2022]
Abstract
BACKGROUND Diaphragm muscle atrophy during mechanical ventilation begins within 24 h and progresses rapidly with significant clinical consequences. Electrical stimulation of the phrenic nerves using invasive electrodes has shown promise in maintaining diaphragm condition by inducing intermittent diaphragm muscle contraction. However, the widespread application of these methods may be limited by their risks as well as the technical and environmental requirements of placement and care. Non-invasive stimulation would offer a valuable alternative method to maintain diaphragm health while overcoming these limitations. METHODS We applied non-invasive electrical stimulation to the phrenic nerve in the neck in healthy volunteers. Respiratory pressure and flow, diaphragm electromyography and mechanomyography, and ultrasound visualization were used to assess the diaphragmatic response to stimulation. The electrode positions and stimulation parameters were systematically varied in order to investigate the influence of these parameters on the ability to induce diaphragm contraction with non-invasive stimulation. RESULTS We demonstrate that non-invasive capture of the phrenic nerve is feasible using surface electrodes without the application of pressure, and characterize the stimulation parameters required to achieve therapeutic diaphragm contractions in healthy volunteers. We show that an optimal electrode position for phrenic nerve capture can be identified and that this position does not vary as head orientation is changed. The stimulation parameters required to produce a diaphragm response at this site are characterized and we show that burst stimulation above the activation threshold reliably produces diaphragm contractions sufficient to drive an inspired volume of over 600 ml, indicating the ability to produce significant diaphragmatic work using non-invasive stimulation. CONCLUSION This opens the possibility of non-invasive systems, requiring minimal specialist skills to set up, for maintaining diaphragm function in the intensive care setting.
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Affiliation(s)
- Conor Keogh
- Nuffield Department of Surgical SciencesUniversity of OxfordOxfordUK
| | - Francisco Saavedra
- Nuffield Department of Surgical SciencesUniversity of OxfordOxfordUK,Electrical Engineering DepartmentUniversidad de ConcepcionConcepciónChile
| | - Sebastian Dubo
- Kinesiology DepartmentUniversidad de ConcepcionConcepciónChile
| | - Pablo Aqueveque
- Electrical Engineering DepartmentUniversidad de ConcepcionConcepciónChile
| | - Paulina Ortega
- Kinesiology DepartmentUniversidad de ConcepcionConcepciónChile
| | - Britam Gomez
- Electrical Engineering DepartmentUniversidad de ConcepcionConcepciónChile
| | - Enrique Germany
- Electrical Engineering DepartmentUniversidad de ConcepcionConcepciónChile
| | - Daniela Pinto
- Electrical Engineering DepartmentUniversidad de ConcepcionConcepciónChile
| | - Rodrigo Osorio
- Electrical Engineering DepartmentUniversidad de ConcepcionConcepciónChile
| | - Francisco Pastene
- Electrical Engineering DepartmentUniversidad de ConcepcionConcepciónChile
| | - Adrian Poulton
- Nuffield Department of Surgical SciencesUniversity of OxfordOxfordUK
| | - Jonathan Jarvis
- School of Sport and Exercise ScienceLiverpool John Moores UniversityLiverpoolUK
| | - Brian Andrews
- Nuffield Department of Surgical SciencesUniversity of OxfordOxfordUK
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Bredemeyer O, Patel S, FitzGerald JJ, Antoniades CA. Oculomotor deficits in Parkinson's disease: Increasing sensitivity using multivariate approaches. Front Digit Health 2022; 4:939677. [PMID: 35990016 PMCID: PMC9387998 DOI: 10.3389/fdgth.2022.939677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 06/27/2022] [Indexed: 11/17/2022] Open
Abstract
Parkinson's disease (PD) affects several domains of neurological function, from lower-level motor programs to higher cognitive processing. As certain types of eye movements (saccades) are fast, non-fatiguing, and can be measured objectively and non-invasively, they are a promising candidate for quantifying motor and cognitive dysfunction in PD, as well as other movement disorders. In this pilot study, we evaluate the latency (reaction time), damping (resistance to oscillation), and amplitude of saccadic movements in two tasks performed by 25 PD patients with mild to moderate disease and 26 age-matched healthy controls. As well as general increases in reaction time caused by PD, the damping of saccadic eye movements was found to be task-dependent and affected by disease. Finally, we introduce a proof-of-concept multivariate model to demonstrate how information from saccadometry can be combined to infer disease status.
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Affiliation(s)
- Oliver Bredemeyer
- NeuroMetrology Group, Nuffield Department of Clinical Neurosciences, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Salil Patel
- NeuroMetrology Group, Nuffield Department of Clinical Neurosciences, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - James J FitzGerald
- NeuroMetrology Group, Nuffield Department of Clinical Neurosciences, Medical Sciences Division, University of Oxford, Oxford, United Kingdom.,Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom.,Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, United Kingdom
| | - Chrystalina A Antoniades
- NeuroMetrology Group, Nuffield Department of Clinical Neurosciences, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
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13
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Keogh C, Saavedra F, Andrews B, FitzGerald JJ. Computation of Activating Fields for Approximation of the Orientation-Specific Neural Response to Electrical Stimulation. Annu Int Conf IEEE Eng Med Biol Soc 2022; 2022:5152-5155. [PMID: 36086379 DOI: 10.1109/embc48229.2022.9871706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Computational methods of determining the response of neural tissue to electrical stimulation have demonstrated value for the development of novel devices and the programming of neuromodulation therapies. Detailed biophysical models are excessively computationally intensive for many applications; simple metrics to approximate activation can speed up progress in this area. The activating function provides such a useful metric. However, this measure, defined for a specific axon orientation, is not immediately applicable to computed electric fields to assess their effects. We demonstrate a method for computation of the activating function generalized to a field in order to allow rapid computation of the effects of stimulation on neural tissue while preserving information on axon orientation. Clinical Relevance- This demonstrates a useful method of approximating the effect of electrical stimulation on nervous tissue for the development of devices and the optimization of parameters for electrical neuromodulation.
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14
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Pereira MF, Buchanan T, Höglinger GU, Bogdanovic M, Tofaris G, Prangnell S, Sarangmat N, FitzGerald JJ, Antoniades CA. Longitudinal changes of early motor and cognitive symptoms in progressive supranuclear palsy: the OxQUIP study. BMJ Neurol Open 2022; 4:e000214. [PMID: 35128403 PMCID: PMC8785161 DOI: 10.1136/bmjno-2021-000214] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 12/19/2021] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Progressive supranuclear palsy (PSP) is a rare neurodegenerative condition characterised by a range of motor and cognitive symptoms. Very little is known about the longitudinal change in these symptoms over time. Moreover, the effectiveness of clinical scales to detect early changes in PSP is still a matter of debate. OBJECTIVE We aimed to determine longitudinal changes in PSP features using multiple closely spaced follow-up time points over a period of 2 years. Methods 28 healthy control and 28 PSP participants, with average time since onset of symptoms of 1.9 years, were prospectively studied every 3 months for up to 24 months. Changes from baseline scores were calculated at each follow-up time point using multiple clinical scales to identify longitudinal progression of motor and cognitive symptoms. RESULTS The Montreal Cognitive Assessment, but not the Mini-Mental State Examination, detected cognitive decline at baseline. Both scales revealed poor longitudinal sensitivity to clinical change in global cognitive symptoms. Conversely, the Movement Disorders Society Unified Parkinson's disease Rating Scale - part III and the PSP Rating Scale (PSPRS) reliably detected motor decline less than 2 years after disease onset. The 'Gait/Midline' PSPRS subscore consistently declined over time, with the earliest change being observed 6 months after baseline assessment. CONCLUSION While better cognitive screening tools are still needed to monitor cognitive decline in PSP, motor decline is consistently captured by clinical rating scales. These results support the inclusion of multiple follow-up time points in longitudinal studies in the early stages of PSP.
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Affiliation(s)
- Marta F Pereira
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - Günter U Höglinger
- Department of Neurology, Technische Universität München & Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Munich, Germany
| | - Marko Bogdanovic
- Department of Neurology, Oxford University Hospitals, Oxford, UK
| | - George Tofaris
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Simon Prangnell
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - James J FitzGerald
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
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15
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Keogh C, Deli A, Zand APD, Zorman MJ, Boccard-Binet SG, Parrott M, Sigalas C, Weiss AR, Stein JF, FitzGerald JJ, Aziz TZ, Green AL, Gillies MJ. Spatial and Temporal Distribution of Information Processing in the Human Dorsal Anterior Cingulate Cortex. Front Hum Neurosci 2022; 16:780047. [PMID: 35370577 PMCID: PMC8973009 DOI: 10.3389/fnhum.2022.780047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 02/18/2022] [Indexed: 11/13/2022] Open
Abstract
The dorsal anterior cingulate cortex (dACC) is a key node in the human salience network. It has been ascribed motor, pain-processing and affective functions. However, the dynamics of information flow in this complex region and how it responds to inputs remain unclear and are difficult to study using non-invasive electrophysiology. The area is targeted by neurosurgery to treat neuropathic pain. During deep brain stimulation surgery, we recorded local field potentials from this region in humans during a decision-making task requiring motor output. We investigated the spatial and temporal distribution of information flow within the dACC. We demonstrate the existence of a distributed network within the anterior cingulate cortex where discrete nodes demonstrate directed communication following inputs. We show that this network anticipates and responds to the valence of feedback to actions. We further show that these network dynamics adapt following learning. Our results provide evidence for the integration of learning and the response to feedback in a key cognitive region.
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Affiliation(s)
- Conor Keogh
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Alceste Deli
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | | | - Mark Jernej Zorman
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | | | - Matthew Parrott
- St Hilda’s College, University of Oxford, Oxford, United Kingdom
| | | | - Alexander R. Weiss
- Department of Neurology, Johns Hopkins University, Baltimore, MD, United States
| | - John Frederick Stein
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - James J. FitzGerald
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Tipu Z. Aziz
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Alexander L. Green
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Martin John Gillies
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
- *Correspondence: Martin John Gillies,
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16
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Brzezicki MA, Bogdanovic M, Buchanan T, FitzGerald JJ, Antoniades CA. Strategy Adherence: A Specific and Rapidly Progressive Deficit in Progressive Supranuclear Palsy. Mov Disord Clin Pract 2021; 8:1272-1274. [PMID: 34761059 PMCID: PMC8564807 DOI: 10.1002/mdc3.13334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/28/2021] [Accepted: 08/15/2021] [Indexed: 11/07/2022] Open
Affiliation(s)
- Maksymilian A Brzezicki
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences University of Oxford Oxford United Kingdom
| | - Marko Bogdanovic
- Oxford University Hospitals NHS Foundation Trust Oxford United Kingdom
| | | | - James J FitzGerald
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences University of Oxford Oxford United Kingdom.,Oxford University Hospitals NHS Foundation Trust Oxford United Kingdom.,Nuffield Department of Surgical Sciences University of Oxford Oxford United Kingdom
| | - Chrystalina A Antoniades
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences University of Oxford Oxford United Kingdom
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17
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Parker T, Raghu A, Huang Y, Gillies MJ, FitzGerald JJ, Aziz T, Green AL. Paired Acute Invasive/Non-invasive Stimulation (PAINS) study: A phase I/II randomized, sham-controlled crossover trial in chronic neuropathic pain. Brain Stimul 2021; 14:1576-1585. [PMID: 34673258 DOI: 10.1016/j.brs.2021.10.384] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 10/09/2021] [Accepted: 10/18/2021] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Dorsal root ganglion (DRG) stimulation, an invasive method of neuromodulation, and transcranial direct current stimulation (tDCS), a non-invasive method of altering cortical excitability, have both proven effective in relieving chronic pain. OBJECTIVE We employed a randomized, sham-controlled crossover study design to investigate whether single-session tDCS would have an additive therapeutic effect alongside DRG stimulation (DRGS) in the treatment of chronic pain. METHODS Sixteen neuropathic pain patients who were previously implanted with DRG stimulators were recruited. Baseline pain scores were established with DRGS-OFF. Pain scores were then recorded with DRGS-ON, after paired sham tDCS stimulation, and after paired active anodal tDCS (a-tDCS) stimulation. For active tDCS, patients were randomized to 'MEG (magnetoencephalography) localized' tDCS or contralateral motor cortex (M1) tDCS for 30 min. EEG recordings and evaluations of tDCS adverse effects were also collected. RESULTS All participants reported the interventions to be tolerable with no significant adverse effects during the session. Paired DRGS/active tDCS resulted in a significant reduction in pain scores compared to paired DRGS-ON/sham tDCS or DRGS alone. There was no difference in the additive effect of M1 vs. MEG-localized tDCS. Significant augmentation of beta activity was observed between DRGS-OFF and DRGS-ON conditions, as well as between paired DRGS-ON/sham tDCS and paired DRGS-ON/active tDCS. CONCLUSION Our results indicate that a single session of tDCS alongside DRGS is safe and can significantly reduce pain acutely in neuropathic pain patients. Paired invasive/non-invasive neuromodulation is a promising new treatment strategy for pain management and should be evaluated further to assess long-term benefits.
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Affiliation(s)
- Tariq Parker
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom; Neurosurgery Department, Massachusetts General Hospital, Boston, MA, USA.
| | - Ashley Raghu
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Yongzhi Huang
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom; Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, 300072, China
| | - Martin J Gillies
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - James J FitzGerald
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Tipu Aziz
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Alexander L Green
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
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18
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Raghu ALB, Eraifej J, Sarangmat N, Stein J, FitzGerald JJ, Payne S, Aziz TZ, Green AL. Pallido-putaminal connectivity predicts outcomes of deep brain stimulation for cervical dystonia. Brain 2021; 144:3589-3596. [PMID: 34293093 PMCID: PMC8719844 DOI: 10.1093/brain/awab280] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/14/2021] [Accepted: 07/01/2021] [Indexed: 11/13/2022] Open
Abstract
Cervical dystonia is a non-degenerative movement disorder characterized by dysfunction of both motor and sensory cortico-basal ganglia networks. Deep brain stimulation targeted to the internal pallidum is an established treatment, but its specific mechanisms remain elusive, and response to therapy is highly variable. Modulation of key dysfunctional networks via axonal connections is likely important. Fifteen patients underwent preoperative diffusion-MRI acquisitions and then progressed to bilateral deep brain stimulation targeting the posterior internal pallidum. Severity of disease was assessed preoperatively and later at follow-up. Scans were used to generate tractography-derived connectivity estimates between the bilateral regions of stimulation and relevant structures. Connectivity to the putamen correlated with clinical improvement, and a series of cortical connectivity-based putaminal parcellations identified the primary motor putamen as the key node (r = 0.70, P = 0.004). A regression model with this connectivity and electrode coordinates explained 68% of the variance in outcomes (r = 0.83, P = 0.001), with both as significant explanatory variables. We conclude that modulation of the primary motor putamen–posterior internal pallidum limb of the cortico-basal ganglia loop is characteristic of successful deep brain stimulation treatment of cervical dystonia. Preoperative diffusion imaging contains additional information that predicts outcomes, implying utility for patient selection and/or individualized targeting.
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Affiliation(s)
- Ashley L B Raghu
- Oxford Functional Neurosurgery, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - John Eraifej
- Oxford Functional Neurosurgery, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.,Department of Neurosurgery, John Radcliffe, Hospital, Oxford University NHS Foundation Trust, Oxford, UK
| | - Nagaraja Sarangmat
- Department of Neurology, John Radcliffe, Hospital, Oxford University NHS Foundation Trust, Oxford, UK
| | - John Stein
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - James J FitzGerald
- Oxford Functional Neurosurgery, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.,Department of Neurosurgery, John Radcliffe, Hospital, Oxford University NHS Foundation Trust, Oxford, UK
| | - Stephen Payne
- Institute of Biomedical Engineering, Department of Engineering, University of Oxford, Oxford, UK
| | - Tipu Z Aziz
- Oxford Functional Neurosurgery, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.,Department of Neurosurgery, John Radcliffe, Hospital, Oxford University NHS Foundation Trust, Oxford, UK
| | - Alexander L Green
- Oxford Functional Neurosurgery, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.,Department of Neurosurgery, John Radcliffe, Hospital, Oxford University NHS Foundation Trust, Oxford, UK
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19
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Sverrisdottir YB, Martin SC, Hadjipavlou G, Kent AR, Paterson DJ, FitzGerald JJ, Green AL. Human Dorsal Root Ganglion Stimulation Reduces Sympathetic Outflow and Long-Term Blood Pressure. ACTA ACUST UNITED AC 2020; 5:973-985. [PMID: 33145461 PMCID: PMC7591825 DOI: 10.1016/j.jacbts.2020.07.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 02/06/2023]
Abstract
DRGS at upper lumbar levels significantly reduces sympathetic nerve firing Reduction in sympathetic activity appears to be independent to pain relief DRGS significantly reduced BP at 6 months and 2 years BP reduction was lateralized to DRGS on the left side Three refractory hypertensives became normotensive after chronic stimulation.
This study hypothesized that dorsal root ganglion (DRG) stimulation would reduce sympathetic nerve activity and would alter hemodynamic variables. This study directly recorded muscle sympathetic nerve activity during ON and OFF stimulation of the DRG while measuring hemodynamic parameters. DRG stimulation significantly reduced the firing frequency of sympathetic nerves, as well as significantly reducing blood pressure, with greater reductions evident when stimulation was left-sided. Left-sided DRG stimulation lowers sympathetic nerve activity, leading to long-term phenotypic changes. This raises the potential of DRG stimulation being used to treat de novo autonomic disorders such as hypertension or heart failure.
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Key Words
- BF, burst frequency
- BI, burst incidence
- BP, blood pressure
- DBP, diastolic blood pressure
- DRG stimulation
- DRG, dorsal root ganglion
- DRGS, dorsal root ganglion stimulation
- HR, heart rate
- MAP, mean arterial pressure
- MME, morphine milligram equivalent
- MRBA%, median relative burst amplitude
- MSNA, muscle sympathetic nerve activity
- SBP, systolic blood pressure
- SCS, spinal cord stimulation
- VAS, visual analogue score of pain
- blood pressure
- hypertension
- neuromodulation
- sympathetic nerve activity
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Affiliation(s)
- Yrsa B Sverrisdottir
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom.,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - Sean C Martin
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom.,Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - George Hadjipavlou
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | | | - David J Paterson
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - James J FitzGerald
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom.,Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Alexander L Green
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom.,Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
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20
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Martin SC, Macey AR, Raghu A, Edwards T, Watson C, Bojanić S, FitzGerald JJ, Green AL. Dorsal Root Ganglion Stimulation for the Treatment of Chronic Neuropathic Knee Pain. World Neurosurg 2020; 143:e303-e308. [PMID: 32711140 DOI: 10.1016/j.wneu.2020.07.102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/15/2020] [Accepted: 07/17/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND To elucidate the efficacy of dorsal root ganglion stimulation in the treatment of chronic neuropathic pain confined to the knee. METHODS Retrospective analysis of prospectively collected data of 14 consecutive patients undergoing dorsal root ganglion stimulation for chronic knee pain, in a single center. The primary outcome measure was pain reduction assessed by numeric pain rating scale score preoperatively and postoperatively. Secondary outcomes included quantification of percentage of pain area covered by stimulation, and reduction in usage of opioid medications. Responders were defined as patients that experienced a greater than or equal to 50% improvement in their preoperative pain score. RESULTS Fourteen patients were implanted with dorsal root ganglion stimulator electrodes; 8 had a single L3 lead implanted, 1 patient had a single L4 lead implanted, and 3 patients had 2 leads implanted (L3 and L4). Two patients had their leads explanted: 1 for non-efficacy, and 1 for repeated electrode displacement. The most common indication for surgery was type 2 complex regional pain syndrome, secondary to either trauma or postoperative chronic pain (either knee replacement or arthroscopy). Median preoperative numeric rating scale score was 8.5, median postoperative numeric rating scale score was 2 (P = 0.002, Wilcoxon signed rank test). The median improvement in pain score was 80%. All 12 patients undergoing chronic stimulation were responders. Median coverage of pain area was 85%. All but 1 patient who was on opioid medication prior to surgery had reduced the dosage of regular opioid. CONCLUSIONS In selected patients, dorsal root ganglion stimulation is an extremely efficacious means of treating otherwise refractory chronic knee pain.
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Affiliation(s)
- Sean C Martin
- Department of Neurological Surgery, Oxford University Hospitals, Oxford, UK; Nuffield Department of Surgical Science, University of Oxford, Oxford, UK.
| | - Alistair R Macey
- Department of Trauma and Orthopaedics, Queen Elizabeth University Hospital, Glasgow, UK
| | - Ashley Raghu
- Nuffield Department of Surgical Science, University of Oxford, Oxford, UK
| | - Tamara Edwards
- Department of Neurological Surgery, Oxford University Hospitals, Oxford, UK
| | - Clare Watson
- Department of Neurological Surgery, Oxford University Hospitals, Oxford, UK
| | - Stana Bojanić
- Department of Neurological Surgery, Oxford University Hospitals, Oxford, UK
| | - James J FitzGerald
- Department of Neurological Surgery, Oxford University Hospitals, Oxford, UK; Nuffield Department of Surgical Science, University of Oxford, Oxford, UK
| | - Alexander L Green
- Department of Neurological Surgery, Oxford University Hospitals, Oxford, UK; Nuffield Department of Surgical Science, University of Oxford, Oxford, UK
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21
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Raghu ALB, Parker T, Aziz TZ, Green AL, Hadjipavlou G, Rea R, FitzGerald JJ. Invasive Electrical Neuromodulation for the Treatment of Painful Diabetic Neuropathy: Systematic Review and Meta-Analysis. Neuromodulation 2020; 24:13-21. [PMID: 32588933 DOI: 10.1111/ner.13216] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/27/2020] [Accepted: 05/15/2020] [Indexed: 12/25/2022]
Abstract
OBJECTIVES Neuromodulation is a treatment option for people suffering from painful diabetic neuropathy (PDN) unresponsive to conventional pharmacotherapy. We systematically examined the pain outcomes of patients with PDN receiving any type of invasive neuromodulation for treatment of neuropathic pain. MATERIALS AND METHODS MEDLINE and Embase were searched through 10 January 2020, without language restriction. All study types were included. Two reviewers independently screened publications and extracted data. Quantitative meta-analysis was performed with pain scores converted to a standard 100-point scale. Randomized controlled trial (RCT) scores were pooled using the inverse variance method and expressed as mean differences. RESULTS RCTs of tonic spinal cord stimulation (t-SCS) showed greater pain improvement than best medical therapy at six months (intention-to-treat: 38/100, 95% CI: 29-47). By per-protocol analysis, case series of t-SCS and dorsal root ganglion stimulation (DRGS) showed improvement by 56 (95% CI: 39-73) and 55 (22-87), respectively, at 12 months. For t-SCS, the rate of failing a therapeutic stimulation trial was 16%, the risk of infection was 4%, and the rate of lead problems requiring surgery to resolve was 4% per year of follow-up. High-frequency SCS and burst SCS both showed efficacy, with few patients studied. CONCLUSION Efficacious, lasting and safe surgical pain management options are available to diabetic patients suffering from PDN. Tonic-SCS is the established standard of treatment; however, other SCS paradigms and DRGS are emerging as promising treatments offering comparable pain benefits, but with few cases published to date. Randomized controlled trials are ongoing to assess their relative merits.
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Affiliation(s)
- Ashley L B Raghu
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Tariq Parker
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Tipu Z Aziz
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.,Department of Neurosurgery, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Alexander L Green
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.,Department of Neurosurgery, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - George Hadjipavlou
- Nuffield Department of Anaesthesia, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Rustam Rea
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - James J FitzGerald
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.,Department of Neurosurgery, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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22
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De Vos M, Prince J, Buchanan T, FitzGerald JJ, Antoniades CA. Discriminating progressive supranuclear palsy from Parkinson's disease using wearable technology and machine learning. Gait Posture 2020; 77:257-263. [PMID: 32078894 DOI: 10.1016/j.gaitpost.2020.02.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 02/05/2020] [Accepted: 02/06/2020] [Indexed: 02/02/2023]
Abstract
BACKGROUND Progressive supranuclear palsy (PSP), a neurodegenerative conditions may be difficult to discriminate clinically from idiopathic Parkinson's disease (PD). It is critical that we are able to do this accurately and as early as possible in order that future disease modifying therapies for PSP may be deployed at a stage when they are likely to have maximal benefit. Analysis of gait and related tasks is one possible means of discrimination. RESEARCH QUESTION Here we investigate a wearable sensor array coupled with machine learning approaches as a means of disease classification. METHODS 21 participants with PSP, 20 with PD, and 39 healthy control (HC) subjects performed a two minute walk, static sway test, and timed up-and-go task, while wearing an array of six inertial measurement units. The data were analysed to determine what features discriminated PSP from PD and PSP from HC. Two machine learning algorithms were applied, Logistic Regression (LR) and Random Forest (RF). RESULTS 17 features were identified in the combined dataset that contained independent information. The RF classifier outperformed the LR classifier, and allowed discrimination of PSP from PD with 86 % sensitivity and 90 % specificity, and PSP from HC with 90 % sensitivity and 97 % specificity. Using data from the single lumbar sensor only resulted in only a modest reduction in classification accuracy, which could be restored using 3 sensors (lumbar, right arm and foot). However for maximum specificity the full six sensor array was needed. SIGNIFICANCE A wearable sensor array coupled with machine learning methods can accurately discriminate PSP from PD. Choice of array complexity depends on context; for diagnostic purposes a high specificity is needed suggesting the more complete array is advantageous, while for subsequent disease tracking a simpler system may suffice.
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Affiliation(s)
- Maarten De Vos
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, OX3 7DQ, Oxford, UK
| | - John Prince
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, OX3 7DQ, Oxford, UK
| | | | - James J FitzGerald
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, OX3 9DU, UK; Nuffield Department of Clinical Neurosciences, NeuroMetrology Lab, University of Oxford, Oxford, OX3 9DU, UK
| | - Chrystalina A Antoniades
- Nuffield Department of Clinical Neurosciences, NeuroMetrology Lab, University of Oxford, Oxford, OX3 9DU, UK.
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23
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Parker T, Huang Y, Raghu AL, FitzGerald JJ, Green AL, Aziz TZ. Dorsal Root Ganglion Stimulation Modulates Cortical Gamma Activity in the Cognitive Dimension of Chronic Pain. Brain Sci 2020; 10:brainsci10020095. [PMID: 32053879 PMCID: PMC7071617 DOI: 10.3390/brainsci10020095] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 01/27/2020] [Accepted: 02/10/2020] [Indexed: 01/09/2023] Open
Abstract
A cognitive task, the n-back task, was used to interrogate the cognitive dimension of pain in patients with implanted dorsal root ganglion stimulators (DRGS). Magnetoencephalography (MEG) signals from thirteen patients with implanted DRGS were recorded at rest and while performing the n-back task at three increasing working memory loads with DRGS-OFF and the task repeated with DRGS-ON. MEG recordings were pre-processed, then power spectral analysis and source localization were conducted. DRGS resulted in a significant reduction in reported pain scores (mean 23%, p = 0.001) and gamma oscillatory activity (p = 0.036) during task performance. DRGS-induced pain relief also resulted in a significantly reduced reaction time during high working memory load (p = 0.011). A significant increase in average gamma power was observed during task performance compared to the resting state. However, patients who reported exacerbations of pain demonstrated a significantly elevated gamma power (F(3,80) = 65.011612, p < 0.001, adjusted p-value = 0.01), compared to those who reported pain relief during the task. Our findings demonstrate that gamma oscillatory activity is differentially modulated by cognitive load in the presence of pain, and this activity is predominantly localized to the prefrontal and anterior cingulate cortices in a chronic pain cohort.
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Parker T, Raghu ALB, FitzGerald JJ, Green AL, Aziz TZ. Multitarget deep brain stimulation for clinically complex movement disorders. J Neurosurg 2020:1-6. [PMID: 31899879 DOI: 10.3171/2019.11.jns192224] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/01/2019] [Indexed: 11/06/2022]
Abstract
Deep brain stimulation (DBS) of single-target nuclei has produced remarkable functional outcomes in a number of movement disorders such as Parkinson's disease, essential tremor, and dystonia. While these benefits are well established, DBS efficacy and strategy for unusual, unclassified movement disorder syndromes is less clear. A strategy of dual pallidal and thalamic electrode placement is a rational approach in such cases where there is profound, medically refractory functional impairment. The authors report a series of such cases: midbrain cavernoma hemorrhage with olivary hypertrophy, spinocerebellar ataxia-like disorder of probable genetic origin, Holmes tremor secondary to brainstem stroke, and hemiballismus due to traumatic thalamic hemorrhage, all treated by dual pallidal and thalamic DBS. All patients demonstrated robust benefit from DBS, maintained in long-term follow-up. This series demonstrates the flexibility and efficacy, but also the limitations, of dual thalamo-pallidal stimulation for managing axial and limb symptoms of tremors, dystonia, chorea, and hemiballismus in patients with complex movement disorders.
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Garcia-Ortega R, Edwards T, Moir L, Aziz TZ, Green AL, FitzGerald JJ. Burst Occipital Nerve Stimulation for Chronic Migraine and Chronic Cluster Headache. Neuromodulation 2019; 22:638-644. [PMID: 31199547 DOI: 10.1111/ner.12977] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 04/02/2019] [Accepted: 04/24/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND Occipital nerve stimulation (ONS) is widely used for headache syndromes including chronic migraine (CM) and chronic cluster headache (CCH). The paraesthesia associated with tonic stimulation can be bothersome and can limit therapy. It is now clear in spinal cord stimulation that paraesthesia-free waveforms can produce effective analgesia, but this has not been reported in ONS for CM or CCH. MATERIALS AND METHODS Seventeen patients (12 CM and 5 CCH) were treated with bilateral burst pattern ONS, including 4 who had previously had tonic ONS. Results were assessed in terms of the frequency of headaches (number of headache days per month for CM, and number of attacks per day for CCH) and their intensity on the numeric pain rating scale. RESULTS Burst ONS produced a statistically significant mean reduction of 10.2 headache days per month in CM. In CCH, there were significant mean reductions in headache frequency (92%) and intensity (42%). CONCLUSION Paraesthesia is not necessary for good quality analgesia in ONS. Larger studies will be required to determine whether the efficacies of the two stimulation modes differ. Burst ONS is imperceptible and therefore potentially amenable to robustly blinded clinical trials.
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Affiliation(s)
- Rodrigo Garcia-Ortega
- Department of Neurosurgery, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Tamara Edwards
- Department of Neurosurgery, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Liz Moir
- Department of Neurosurgery, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Tipu Z Aziz
- Department of Neurosurgery, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Alexander L Green
- Department of Neurosurgery, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - James J FitzGerald
- Department of Neurosurgery, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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Martin S, Hadjipavlou G, Garcia Ortega R, Moir L, Edwards T, Bojanic S, Green AL, FitzGerald JJ. The Importance of the Location of Dorsal Root Ganglion Stimulator Electrodes Within the Nerve Root Exit Foramen. Neuromodulation 2019; 23:245-251. [PMID: 31070832 DOI: 10.1111/ner.12959] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/04/2019] [Accepted: 03/20/2019] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To quantify the relationship between the electrical power requirement to achieve pain relief and the position of the active electrode of dorsal root ganglion stimulators within the spinal nerve root exit foramen. MATERIALS AND METHODS Retrospective analysis of prospectively collected data of 92 consecutive patients undergoing dorsal root ganglion stimulation (DRGS) for chronic pain in a single center. Cervical and sacral cases, and failed trials/explanted DRGS were excluded, so we report on 57 patients with 78 implanted leads. Anteroposterior and lateral fluoroscopic images of the lead in the exit foramen were examined, and the active electrode positions were put into categories depending on their location relative to fixed anatomical landmarks. The clinical outcome and the power requirements for each of these groups of electrodes were then analyzed. Overall pain outcome was assessed by numeric pain rating scale score pre-operatively and post-operatively. RESULTS There was no significant relationship between power requirements and mediolateral electrode position, although the lowest average was observed with electrode positions directly below the center of the pedicle. On lateral x-ray, the lowest power requirements were observed in the electrodes positioned superodorsally or dorsally within the foramen. Importantly, power requirements in this location were consistently low, while the power requirements in other locations were not only higher but also much more variable. Electrodes in the superodorsal position required a median output power almost four times lower than electrodes in other positions (p = 0.002). Clinical outcome was not significantly related to power requirement or foraminal position. CONCLUSION Aiming for a superodorsal electrode position on lateral intraoperative fluoroscopy is desirable, since siting leads in this location reduces the required stimulator output power very substantially and thus will extend battery life. Position within the foramen does not determine clinical outcome, and so the implanter can safely aim for the low power site without detriment to the analgesic efficacy of the system.
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Affiliation(s)
- Sean Martin
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - George Hadjipavlou
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.,Nuffield Department of Anaesthetics, John Radcliffe Hospital, Oxford, UK
| | | | - Liz Moir
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - Tamara Edwards
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - Stana Bojanic
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - Alexander L Green
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.,Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - James J FitzGerald
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.,Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK
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Deer TR, Pope JE, Lamer TJ, Grider JS, Provenzano D, Lubenow TR, FitzGerald JJ, Hunter C, Falowski S, Sayed D, Baranidharan G, Patel NK, Davis T, Green A, Pajuelo A, Epstein LJ, Harned M, Liem L, Christo PJ, Chakravarthy K, Gilmore C, Huygen F, Lee E, Metha P, Nijhuis H, Patterson DG, Petersen E, Pilitsis JG, Rowe JJ, Rupert MP, Skaribas I, Sweet J, Verrills P, Wilson D, Levy RM, Mekhail N. The Neuromodulation Appropriateness Consensus Committee on Best Practices for Dorsal Root Ganglion Stimulation. Neuromodulation 2018; 22:1-35. [PMID: 30246899 DOI: 10.1111/ner.12845] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/03/2018] [Accepted: 05/29/2018] [Indexed: 12/21/2022]
Abstract
INTRODUCTION The Neuromodulation Appropriateness Consensus Committee (NACC) is dedicated to improving the safety and efficacy of neuromodulation and thus improving the lives of patients undergoing neuromodulation therapies. With continued innovations in neuromodulation comes the need for evolving reviews of best practices. Dorsal root ganglion (DRG) stimulation has significantly improved the treatment of complex regional pain syndrome (CRPS), among other conditions. Through funding and organizational leadership by the International Neuromodulation Society (INS), the NACC reconvened to develop the best practices consensus document for the selection, implantation and use of DRG stimulation for the treatment of chronic pain syndromes. METHODS The NACC performed a comprehensive literature search of articles about DRG published from 1995 through June, 2017. A total of 2538 article abstracts were then reviewed, and selected articles graded for strength of evidence based on scoring criteria established by the US Preventive Services Task Force. Graded evidence was considered along with clinical experience to create the best practices consensus and recommendations. RESULTS The NACC achieved consensus based on peer-reviewed literature and experience to create consensus points to improve patient selection, guide surgical methods, improve post-operative care, and make recommendations for management of patients treated with DRG stimulation. CONCLUSION The NACC recommendations are intended to improve patient care in the use of this evolving therapy for chronic pain. Clinicians who choose to follow these recommendations may improve outcomes.
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Affiliation(s)
| | | | - Tim J Lamer
- Division of Pain Medicine, Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
| | - Jay S Grider
- UKHealthCare Pain Services, Department of Anesthesiology, University of Kentucky College of Medicine, Lexington, KY, USA
| | | | | | - James J FitzGerald
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK.,Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Corey Hunter
- Ainsworth Institute of Pain Management, New York, NY, USA
| | - Steven Falowski
- Functional Neurosurgery, St. Lukes University Health Network, Bethlehem, PA, USA
| | - Dawood Sayed
- University of Kansas Medical Center, Kansas City, KS, USA
| | | | - Nikunj K Patel
- Institute of Clinical Neurosciences, Department of Neurosurgery, Southmead Hospital, University of Bristol, Bristol, UK
| | | | - Alex Green
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | | | - Michael Harned
- Department of Anesthesiology, University of Kentucky, Lexington, KY, USA
| | - Liong Liem
- St. Antonius Hospital, Nieuwegein, The Netherlands
| | | | | | | | - Frank Huygen
- Erasmus University Hospital, Rotterdam, The Netherlands
| | - Eric Lee
- Summit Pain Alliance, Santa Rosa, CA, USA
| | | | | | | | - Erika Petersen
- Department of Neurosurgery, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Julie G Pilitsis
- Neurosurgery and Neuroscience & Experimental Therapeutics, Albany Medical College, Albany, NY, USA
| | | | | | | | - Jennifer Sweet
- Case Western Reserve University, Stereotactic & Functional Neurosurgery, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
| | | | - Derron Wilson
- Goodman Campbell Brain and Spine, Indiana University School of Medicine Department of Neurological Surgery, Indianapolis, IN, USA
| | | | - Nagy Mekhail
- Evidence-Based Pain Management Research and Education, Cleveland Clinic, Cleveland, OH, USA
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Weiss AR, Gillies MJ, Philiastides MG, Apps MA, Whittington MA, FitzGerald JJ, Boccard SG, Aziz TZ, Green AL. Dorsal Anterior Cingulate Cortices Differentially Lateralize Prediction Errors and Outcome Valence in a Decision-Making Task. Front Hum Neurosci 2018; 12:203. [PMID: 29872384 PMCID: PMC5972193 DOI: 10.3389/fnhum.2018.00203] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/30/2018] [Indexed: 11/13/2022] Open
Abstract
The dorsal anterior cingulate cortex (dACC) is proposed to facilitate learning by signaling mismatches between the expected outcome of decisions and the actual outcomes in the form of prediction errors. The dACC is also proposed to discriminate outcome valence-whether a result has positive (either expected or desirable) or negative (either unexpected or undesirable) value. However, direct electrophysiological recordings from human dACC to validate these separate, but integrated, dimensions have not been previously performed. We hypothesized that local field potentials (LFPs) would reveal changes in the dACC related to prediction error and valence and used the unique opportunity offered by deep brain stimulation (DBS) surgery in the dACC of three human subjects to test this hypothesis. We used a cognitive task that involved the presentation of object pairs, a motor response, and audiovisual feedback to guide future object selection choices. The dACC displayed distinctly lateralized theta frequency (3-8 Hz) event-related potential responses-the left hemisphere dACC signaled outcome valence and prediction errors while the right hemisphere dACC was involved in prediction formation. Multivariate analyses provided evidence that the human dACC response to decision outcomes reflects two spatiotemporally distinct early and late systems that are consistent with both our lateralized electrophysiological results and the involvement of the theta frequency oscillatory activity in dACC cognitive processing. Further findings suggested that dACC does not respond to other phases of action-outcome-feedback tasks such as the motor response which supports the notion that dACC primarily signals information that is crucial for behavioral monitoring and not for motor control.
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Affiliation(s)
- Alexander R Weiss
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom.,Neurophysiological Pharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Martin J Gillies
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Marios G Philiastides
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, United Kingdom
| | - Matthew A Apps
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
| | | | - James J FitzGerald
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Sandra G Boccard
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Tipu Z Aziz
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Alexander L Green
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
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Abstract
Until recently the assessment of many movement disorders has relied on clinical rating scales that despite careful design are inherently subjective and non-linear. This makes accurate and truly observer-independent quantification difficult and limits the use of sensitive parametric statistical methods. At last, devices capable of measuring neurological problems quantitatively are becoming readily available. Examples include the use of oculometers to measure eye movements and accelerometers to measure tremor. Many applications are being developed for use on smartphones. The benefits include not just more accurate disease quantification, but also consistency of data for longitudinal studies, accurate stratification of patients for entry into trials, and the possibility of automated data capture for remote follow-up. In this mini review, we will look at movement disorders with a particular focus on Parkinson's disease, describe some of the limitations of existing clinical evaluation tools, and illustrate the ways in which objective metrics have already been successful.
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Affiliation(s)
- James J FitzGerald
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Zhongjiao Lu
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Department of Neurology, West China Hospital of Medicine, Sichuan University, Chengdu, China
| | - Prem Jareonsettasin
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Exeter College, University of Oxford, Oxford, United Kingdom
| | - Chrystalina A Antoniades
- NeuroMetrology Lab, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
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Harrison C, Epton S, Bojanic S, Green AL, FitzGerald JJ. The Efficacy and Safety of Dorsal Root Ganglion Stimulation as a Treatment for Neuropathic Pain: A Literature Review. Neuromodulation 2017; 21:225-233. [PMID: 28960653 DOI: 10.1111/ner.12685] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 07/26/2017] [Accepted: 07/28/2017] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Dorsal root ganglion stimulation (DRGS) received its first regulatory approval (CE marking in Europe) in late 2011, and so its use is now almost six years old. Several thousand patients have already been treated, and a landmark trial in lower limb complex regional pain syndrome (CRPS) and causalgia has recently been published. METHODS In this review we have summarized the literature to date on the use of DRGS in the treatment of neuropathic pain. RESULTS The results so far are encouraging, with reports of successful use in treating a wide range of indications including postsurgical pain, CRPS, and phantom pain. Treatment of failed back surgery syndrome (FBSS) appears less successful. The therapy is still young, and long term results are not yet available. There is now good randomized clinical trial (RCT) evidence that DRGS provides superior pain relief to spinal cord stimulation for CRPS and causalgia of the lower limb, and produces stimulation that is more posturally stable, with more precise paraesthesia coverage. However evidence of this quality for other indications and pain locations is lacking. CONCLUSION There is now Class A RCT evidence that DRGS provides superior pain relief to SCS for CRPS and causalgia of the lower limb. In the coming years we hope that randomized controlled trials will be performed on an indication-by-indication basis, which, together with the publication of longer term follow-up data, will provide a more complete understanding of the role of DRGS in the treatment of neuropathic pain syndromes.
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Affiliation(s)
- Conrad Harrison
- John Radcliffe Hospital, University of Oxford Medical Sciences Office, Oxford, UK
| | - Sarah Epton
- Vascular Research Department, St George's Hospital, London, UK
| | - Stana Bojanic
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - Alexander L Green
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK.,Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - James J FitzGerald
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK.,Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
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FitzGerald JJ, Lubenow TJ, Verrills P. Re: Thanks But No Thanks. Pain Med 2017; 18:1820. [PMID: 28926659 DOI: 10.1093/pm/pnx202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- James J FitzGerald
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Timothy J Lubenow
- Department of Anesthesiology, Rush University Medical Center, Chicago, Illinois, USA
| | - Paul Verrills
- Metro Pain Group, Monash Clinical Research Group, Melbourne, Australia
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Roy HA, Pond D, Roy C, Forrow B, Foltynie T, Zrinzo L, Akram H, Aziz TZ, FitzGerald JJ, Green AL. Effects of pedunculopontine nucleus stimulation on human bladder function. Neurourol Urodyn 2017; 37:726-734. [DOI: 10.1002/nau.23321] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 04/11/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Holly A. Roy
- Department of Neurosurgery; Oxford University Hospitals Trust; Oxford UK
- Nuffield Department of Surgical Sciences; University of Oxford; Oxford UK
| | - Debbie Pond
- OUH Adult Continence Service, Infection Control Department; Oxford University Hospitals Trust; Oxford UK
| | | | - Beth Forrow
- Department of Neurosurgery; Oxford University Hospitals Trust; Oxford UK
| | - Thomas Foltynie
- Sobell Department of Motor Neuroscience and Movement Disorders; University College London, Institute of Neurology; London UK
| | - Ludvic Zrinzo
- Sobell Department of Motor Neuroscience and Movement Disorders; University College London, Institute of Neurology; London UK
| | - Harith Akram
- Sobell Department of Motor Neuroscience and Movement Disorders; University College London, Institute of Neurology; London UK
| | - Tipu Z. Aziz
- Department of Neurosurgery; Oxford University Hospitals Trust; Oxford UK
- Nuffield Department of Surgical Sciences; University of Oxford; Oxford UK
| | - James J. FitzGerald
- Department of Neurosurgery; Oxford University Hospitals Trust; Oxford UK
- Nuffield Department of Surgical Sciences; University of Oxford; Oxford UK
| | - Alexander L. Green
- Department of Neurosurgery; Oxford University Hospitals Trust; Oxford UK
- Nuffield Department of Surgical Sciences; University of Oxford; Oxford UK
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Boccard SGJ, Rebelo P, Cheeran B, Green A, FitzGerald JJ, Aziz TZ. Post-Traumatic Tremor and Thalamic Deep Brain Stimulation: Evidence for Use of Diffusion Tensor Imaging. World Neurosurg 2016; 96:607.e7-607.e11. [PMID: 27693821 DOI: 10.1016/j.wneu.2016.09.079] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/16/2016] [Accepted: 09/20/2016] [Indexed: 01/11/2023]
Abstract
BACKGROUND Deep brain stimulation (DBS) is a well-established treatment to reduce tremor, notably in Parkinson disease. DBS may also be effective in post-traumatic tremor, one of the most common movement disorders caused by head injury. However, the cohorts of patients often have multiple lesions that may impact the outcome depending on which fiber tracts are affected. CASE DESCRIPTION A 20-year-old man presented after road traffic accident with severe closed head injury and polytrauma. Computed tomography scan showed left frontal and basal ganglia hemorrhagic contusions and intraventricular hemorrhage. A disabling tremor evolved in step with motor recovery. Despite high-intensity signals in the intended thalamic target, a visual analysis of the preoperative diffusion tensor imaging revealed preservation of connectivity of the intended target, ventralis oralis posterior thalamic nucleus (VOP). This was confirmed by the postoperative tractography study presented here. DBS of the VOP/zona incerta was performed. Six months postimplant, marked improvement of action (postural, kinetic, and intention) tremor was achieved. CONCLUSIONS We demonstrated a strong connectivity between the VOP and the superior frontal gyrus containing the premotor cortex and other central brain areas responsible for movement control. In spite of an existing lesion in the target, the preservation of these tracts may be relevant to the improvement of the patient's symptoms by DBS.
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Affiliation(s)
- Sandra G J Boccard
- Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, Oxford, United Kingdom.
| | - Pedro Rebelo
- Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, Oxford, United Kingdom
| | - Binith Cheeran
- Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, Oxford, United Kingdom
| | - Alexander Green
- Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, Oxford, United Kingdom
| | - James J FitzGerald
- Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, Oxford, United Kingdom
| | - Tipu Z Aziz
- Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Departments of Clinical Neuroscience and Surgery, University of Oxford, Oxford, United Kingdom
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Abstract
The authors report the first case of successful implantation of a dorsal root ganglion stimulator at L1 and L2 for sustained improvement in chronic pelvic girdle pain.
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Affiliation(s)
- David C L Rowland
- a Oxford University Medical School, University of Oxford , Oxford , UK
| | - Daniel Wright
- b Department of Neurosurgery , John Radcliffe Hospital , Oxford , UK
| | - Liz Moir
- b Department of Neurosurgery , John Radcliffe Hospital , Oxford , UK
| | | | - Alexander L Green
- b Department of Neurosurgery , John Radcliffe Hospital , Oxford , UK
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Abstract
The oculomotor system involves a large number of brain areas including parts of the basal ganglia, and various neurodegenerative diseases including Parkinson's and Huntington's can disrupt it. People with Parkinson's disease, for example, tend to have increased saccadic latencies. Consequently, the quantitative measurement of saccadic eye movements has received considerable attention as a potential biomarker for neurodegenerative conditions. A lot more can be learned about the brain in both health and disease by observing what happens to eye movements when the function of specific brain areas is perturbed. Deep brain stimulation is a surgical intervention used for the management of a range of neurological conditions including Parkinson's disease, in which stimulating electrodes are placed in specific brain areas including several sites in the basal ganglia. Eye movement measurements can then be made with the stimulator systems both off and on and the results compared. With suitable experimental design, this approach can be used to study the pathophysiology of the disease being treated, the mechanism by which DBS exerts it beneficial effects, and even aspects of normal neurophysiology.
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Abstract
OBJECTIVE Medical implants made of non-biological materials provoke a chronic inflammatory response, resulting in the deposition of a collagenous scar tissue (ST) layer on their surface, that gradually thickens over time. This is a critical problem for neural interfaces. Scar build-up on electrodes results in a progressive decline in signal level because the scar tissue gradually separates axons away from the recording contacts. In regenerative sieves and microchannel electrodes, progressive scar deposition will constrict and may eventually choke off the sieve hole or channel lumen. Interface designs need to address this issue if they are to be fit for long term use. This study examines a novel method of inhibiting the formation and thickening of the fibrous scar. APPROACH Research to date has mainly focused on methods of preventing stimulation of the foreign body response by implant surface modification. In this paper a pharmacological approach using drug elution to suppress chronic inflammation is introduced. Microchannel implants made of silicone doped with the steroid drug dexamethasone were implanted in the rat sciatic nerve for periods of up to a year. Tissue from within the microchannels was compared to that from control devices that did not release any drug. MAIN RESULTS In the drug eluting implants the scar layer was significantly thinner at all timepoints, and unlike the controls it did not continue to thicken after 6 months. Control implants supported axon regeneration well initially, but axon counts fell rapidly at later timepoints as scar thickened. Axon counts in drug eluting devices were initially much lower, but increased rather than declined and by one year were significantly higher than in controls. SIGNIFICANCE Drug elution offers a potential long term solution to the problem of performance degradation due to scarring around neural implants.
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Affiliation(s)
- James J FitzGerald
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
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van Hartevelt TJ, Cabral J, Møller A, FitzGerald JJ, Green AL, Aziz TZ, Deco G, Kringelbach ML. Evidence from a rare case study for Hebbian-like changes in structural connectivity induced by long-term deep brain stimulation. Front Behav Neurosci 2015; 9:167. [PMID: 26175675 PMCID: PMC4485173 DOI: 10.3389/fnbeh.2015.00167] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 06/15/2015] [Indexed: 01/09/2023] Open
Abstract
It is unclear whether Hebbian-like learning occurs at the level of long-range white matter connections in humans, i.e., where measurable changes in structural connectivity (SC) are correlated with changes in functional connectivity. However, the behavioral changes observed after deep brain stimulation (DBS) suggest the existence of such Hebbian-like mechanisms occurring at the structural level with functional consequences. In this rare case study, we obtained the full network of white matter connections of one patient with Parkinson’s disease (PD) before and after long-term DBS and combined it with a computational model of ongoing activity to investigate the effects of DBS-induced long-term structural changes. The results show that the long-term effects of DBS on resting-state functional connectivity is best obtained in the computational model by changing the structural weights from the subthalamic nucleus (STN) to the putamen and the thalamus in a Hebbian-like manner. Moreover, long-term DBS also significantly changed the SC towards normality in terms of model-based measures of segregation and integration of information processing, two key concepts of brain organization. This novel approach using computational models to model the effects of Hebbian-like changes in SC allowed us to causally identify the possible underlying neural mechanisms of long-term DBS using rare case study data. In time, this could help predict the efficacy of individual DBS targeting and identify novel DBS targets.
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Affiliation(s)
- Tim J van Hartevelt
- Department of Psychiatry, University of Oxford Oxford, UK ; Center of Functionally Integrative Neuroscience (CFIN), Aarhus University Aarhus, Denmark
| | - Joana Cabral
- Department of Psychiatry, University of Oxford Oxford, UK ; Center of Brain and Cognition, Theoretical and Computational Neuroscience Group, Universitat Pompeu Fabra Barcelona, Spain
| | - Arne Møller
- Center of Functionally Integrative Neuroscience (CFIN), Aarhus University Aarhus, Denmark
| | - James J FitzGerald
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital Oxford, UK
| | - Alexander L Green
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital Oxford, UK
| | - Tipu Z Aziz
- Department of Psychiatry, University of Oxford Oxford, UK ; Nuffield Department of Surgical Sciences, John Radcliffe Hospital Oxford, UK
| | - Gustavo Deco
- Center of Brain and Cognition, Theoretical and Computational Neuroscience Group, Universitat Pompeu Fabra Barcelona, Spain ; Institució Catalana de la Recerca i Estudis Avançats (ICREA), Universitat Pompeu Fabra Barcelona, Spain
| | - Morten L Kringelbach
- Department of Psychiatry, University of Oxford Oxford, UK ; Center of Functionally Integrative Neuroscience (CFIN), Aarhus University Aarhus, Denmark ; Nuffield Department of Surgical Sciences, John Radcliffe Hospital Oxford, UK
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Tan H, Pogosyan A, Ashkan K, Cheeran B, FitzGerald JJ, Green AL, Aziz T, Foltynie T, Limousin P, Zrinzo L, Brown P. Subthalamic nucleus local field potential activity helps encode motor effort rather than force in parkinsonism. J Neurosci 2015; 35:5941-9. [PMID: 25878267 PMCID: PMC4397595 DOI: 10.1523/jneurosci.4609-14.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 02/17/2015] [Accepted: 02/22/2015] [Indexed: 12/25/2022] Open
Abstract
Local field potential (LFP) recordings from patients with deep brain stimulation electrodes in the basal ganglia have suggested that frequency-specific activities correlate with force or effort, but previous studies have not been able to disambiguate the two. Here, we dissociated effort from actual force generated by contrasting the force generation of different fingers while recording LFP activity from the subthalamic nucleus (STN) in patients with Parkinson's disease who had undergone functional surgery. Patients were studied while on their normal dopaminergic medication. We investigated the relationship between frequency-specific oscillatory activity in the STN and voluntary flexion of either the index or little finger at different effort levels. At each tested effort level (10%, 25%, and 40% of the maximal voluntary contraction force of each individual finger), the index finger generated larger force than the little finger. Movement-related suppression of beta-band power in the STN LFP was significantly modulated by effort, but not by which finger was used, suggesting that the beta suppression in the STN LFP during sustained contraction serves as a proxy for effort. The absolute force scaled with beta power suppression, but with the scaling determined by the maximal voluntary contraction force of the motor effector. Our results argue against the hypothesis that the basal ganglia are directly involved in the parameterization of force during movement and support a role of the STN in the control of motor effort to be attributed to a response.
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Affiliation(s)
- Huiling Tan
- Medical Research Council Brain Network Dynamics Unit at the University of Oxford, Oxford, OX1 3TH, Functional Neurosurgery, Experimental Neurology Group, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom,
| | - Alek Pogosyan
- Medical Research Council Brain Network Dynamics Unit at the University of Oxford, Oxford, OX1 3TH, Functional Neurosurgery, Experimental Neurology Group, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Keyoumars Ashkan
- Department of Neurosurgery, Kings College Hospital, Kings College London, London SE5 9RS, United Kingdom, and
| | - Binith Cheeran
- Functional Neurosurgery, Experimental Neurology Group, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - James J FitzGerald
- Functional Neurosurgery, Experimental Neurology Group, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Alexander L Green
- Functional Neurosurgery, Experimental Neurology Group, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Tipu Aziz
- Functional Neurosurgery, Experimental Neurology Group, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Thomas Foltynie
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London WC1N 3BG, United Kingdom
| | - Patricia Limousin
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London WC1N 3BG, United Kingdom
| | - Ludvic Zrinzo
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London WC1N 3BG, United Kingdom
| | - Peter Brown
- Medical Research Council Brain Network Dynamics Unit at the University of Oxford, Oxford, OX1 3TH, Functional Neurosurgery, Experimental Neurology Group, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom
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FitzGerald JJ, Rosendal F, de Pennington N, Joint C, Forrow B, Fletcher C, Green AL, Aziz TZ. Long-term outcome of deep brain stimulation in generalised dystonia: a series of 60 cases. J Neurol Neurosurg Psychiatry 2014; 85:1371-6. [PMID: 24691580 DOI: 10.1136/jnnp-2013-306833] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND There is solid evidence of the long term efficacy of deep brain stimulation of the globus pallidus pars interna in the treatment of generalised dystonia. However there are conflicting reports concerning whether certain subgroups gain more benefit from treatment than others. We analysed the results of a series of 60 cases to evaluate the effects of previously proposed prognostic factors including dystonia aetiology, dystonia phenotype, age at onset of dystonia, and duration of dystonia prior to treatment. METHODS 60 patients with medically intractable primary or secondary generalised dystonia were treated with deep brain stimulation of the globus pallidus pars interna during the period 1999-2010 at the Department of Neurosurgery in Oxford, UK. Patients were assessed using the Burke-Fahn-Marsden (BFM) Dystonia Rating Scale prior to surgery, 6 months after implantation and thereafter at 1 year, 2 years and 5 years follow-up. RESULTS The group showed mean improvements in the BFM severity and disability scores of 43% and 27%, respectively, by 6 months, and this was sustained. The results in 11 patients with DYT gene mutations were significantly better than in non-genetic primary cases. The results in 12 patients with secondary dystonia were not as good as those seen in non-genetic primary cases but there remained a significant beneficial effect. Age of onset of dystonia, duration of disease prior to surgery, and myoclonic versus torsional disease phenotype had no significant effect on outcome. CONCLUSIONS The aetiology of dystonia was the sole factor predicting a better or poorer outcome from globus pallidus pars interna stimulation in this series of patients with generalised dystonia. However even the secondary cases that responded the least well had a substantial reduction in BFM scores compared with preoperative clinical assessments, and these patients should still be considered for deep brain stimulation.
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Affiliation(s)
- J J FitzGerald
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - F Rosendal
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK Department of Neurosurgery, Aarhus University Hospital, Aarhus, Denmark
| | - N de Pennington
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - C Joint
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - B Forrow
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - C Fletcher
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - A L Green
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - T Z Aziz
- Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
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FitzGerald JJ, Lago N, Benmerah S, Serra J, Watling CP, Cameron RE, Tarte E, Lacour SP, McMahon SB, Fawcett JW. Erratum: A regenerative microchannel neural interface for recording from and stimulating peripheral axons in vivo. J Neural Eng 2012. [DOI: 10.1088/1741-2552/9/2/029601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Antoniades CA, Buttery P, FitzGerald JJ, Barker RA, Carpenter RHS, Watts C. Deep brain stimulation: eye movements reveal anomalous effects of electrode placement and stimulation. PLoS One 2012; 7:e32830. [PMID: 22427894 PMCID: PMC3299699 DOI: 10.1371/journal.pone.0032830] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 02/06/2012] [Indexed: 11/20/2022] Open
Abstract
One of the major difficulties in evaluating the efficacy of deep brain stimulation (DBS), or understanding its mechanism, is the need to distinguish the effects of stimulation itself from those of the lesion inevitably created during surgery. Recent work has shown that DBS of the subthalamic nucleus in Parkinson's disease greatly reduces the time it takes the eyes to make a saccade in response to a visual stimulus. Since this saccadic latency can be rapidly and objectively measured, we used it to compare the effects of surgery and of stimulation. We used a saccadometer to measure the saccadic latencies of 9 DBS patients (1) preoperatively, (2) the day after insertion of subthalamic nucleus electrodes, (3) three weeks later, prior to turning on the stimulator, and (4) after commencement of stimulation. Patients were on their anti-Parkinsonian medication throughout the study. It revealed an entirely unexpected and puzzling finding. As in previous studies an amelioration of symptoms is seen immediately after surgery, and then a further improvement when finally the stimulator is turned on, but in the case of saccadic latency the pattern is different: surgery produces a transient increase in latency, returning to baseline within three weeks, while subsequent stimulation reduced latency. Thus the differential effects of electrode placement and stimulation are completely different for saccades and for more general motor symptoms. This important finding rules out some over-simple interpretations of the mechanism of DBS, and needs to be taken into account in future attempts at modelling the neurophysiology of DBS.
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FitzGerald JJ, Lago N, Benmerah S, Serra J, Watling CP, Cameron RE, Tarte E, Lacour SP, McMahon SB, Fawcett JW. A regenerative microchannel neural interface for recording from and stimulating peripheral axons in vivo. J Neural Eng 2012; 9:016010. [PMID: 22258138 DOI: 10.1088/1741-2560/9/1/016010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Neural interfaces are implanted devices that couple the nervous system to electronic circuitry. They are intended for long term use to control assistive technologies such as muscle stimulators or prosthetics that compensate for loss of function due to injury. Here we present a novel design of interface for peripheral nerves. Recording from axons is complicated by the small size of extracellular potentials and the concentration of current flow at nodes of Ranvier. Confining axons to microchannels of ~100 µm diameter produces amplified potentials that are independent of node position. After implantation of microchannel arrays into rat sciatic nerve, axons regenerated through the channels forming 'mini-fascicles', each typically containing ~100 myelinated fibres and one or more blood vessels. Regenerated motor axons reconnected to distal muscles, as demonstrated by the recovery of an electromyogram and partial prevention of muscle atrophy. Efferent motor potentials and afferent signals evoked by muscle stretch or cutaneous stimulation were easily recorded from the mini-fascicles and were in the range of 35-170 µV. Individual motor units in distal musculature were activated from channels using stimulus currents in the microampere range. Microchannel interfaces are a potential solution for applications such as prosthetic limb control or enhancing recovery after nerve injury.
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Watling CP, Lago N, Benmerah S, FitzGerald JJ, Tarte E, McMahon S, Lacour SP, Cameron RE. Novel use of X-ray micro computed tomography to image rat sciatic nerve and integration into scaffold. J Neurosci Methods 2010; 188:39-44. [PMID: 20138083 DOI: 10.1016/j.jneumeth.2010.01.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 01/26/2010] [Accepted: 01/27/2010] [Indexed: 01/25/2023]
Abstract
This paper describes how specimens of nervous tissue can be prepared for successful imaging in X-ray Micro Computed Tomography (microCT), and how this method can be used to study the integration of nervous tissue into a polymeric scaffold. The sample preparation involves staining the biological tissue with osmium tetroxide to increase its X-ray attenuation, and a technique for maintaining the specimen in a moist environment during the experiment to prevent drying and shrinkage. Using this method it was possible to observe individual nerve fascicles and their relationship to the 3-D tissue structure. A scaffold supporting a regenerated sciatic nerve was similarly stained to distinguish the nervous tissue from the scaffold, and to observe how the nerve grew through a 2.5 mm long, 100 microm x 100 microm cross-section channel polyimide array. Furthermore, blood vessels could be identified in these images, and it was possible to monitor how a large proximal blood vessel split through the channel scaffold and proceeded down individual channels. This paper explains how microCT is a useful tool both for studying the location and extent of growth into a polymeric scaffold, and for determining whether the regenerated tissue has blood supply.
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Affiliation(s)
- C P Watling
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK
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Abstract
Microchannels containing electrodes have a number of favourable properties that make them potentially suitable as the basis of a peripheral nerve interface design. In this study we have evaluated microchannel recording in vitro in the presence of a realistic simulation of electrical interference from musculature adjacent to an implanted interface. Tripolar recording and high-pass filtration both help improve signal discrimination. At high noise levels designed to replicate the effects of intense muscular activity, a combination of both these techniques is required, and only signals in larger axons can be recovered.
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Affiliation(s)
- James J FitzGerald
- Cambridge Centre for Brain Repair, University of Cambridge, Cambridge, CB2 2PY, UK.
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FitzGerald JJ, Jaspan T, Cartmill M. A benign pilomatrixoma mimicking a skull vault tumour in a 9-month-old girl. Br J Neurosurg 2003; 17:469-70. [PMID: 14635757 DOI: 10.1080/02688690310001611297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- J J FitzGerald
- Department of Neurosurgery, University Hospital Nottingham, Queens Medical Centre, UK
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Abstract
Bungee jumping has been exploited commercially for 13 years and proprietors claim a good safety record. However, published case reports document a wide variety of possible injuries. To this list, we add a report of a subdural haematoma sustained during a variant of the sport, the 'reverse' bungee jump.
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Affiliation(s)
- J J FitzGerald
- Department of Neurosurgery, University Hospital Nottingham, UK
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