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Monaghan AS, Ofori E, Fling BW, Peterson DS. Associating white matter microstructural integrity and improvements in reactive stepping in people with Parkinson's Disease. Brain Imaging Behav 2024:10.1007/s11682-024-00867-w. [PMID: 38530517 DOI: 10.1007/s11682-024-00867-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2024] [Indexed: 03/28/2024]
Abstract
Reactive steps are rapid responses after balance challenges. People with Parkinson's Disease (PwPD) demonstrate impaired reactive stepping, increasing fall-risk. Although PwPD can improve steps through practice, the neural mechanisms contributing to improved reactive stepping are poorly understood. This study investigated white-matter correlates of responsiveness to reactive step training in PwPD. In an eighteen-week multiple-baseline study, participants (n = 22) underwent baseline assessments (B1 and B2 two-weeks apart), a two-week training protocol, and post-training assessments immediately (P1) and two-months (P2) post-training. Assessments involved three backward reactive step trials, measuring anterior-posterior margin of stability (AP MOS), step length, and step latency. Tract-Based Spatial Statistics correlated white-matter integrity (fractional anisotropy (FA) and radial diffusivity (RD)) with retained (P2-B2) and immediate improvements (P1-B2) in stepping. Significant and sustained improvements in step length and AP MOS were observed. Greater retention of step length improvement correlated with increased FA in the left anterior thalamic radiation (ATR), left posterior thalamic radiation (PTR), left superior longitudinal fasciculus (SLF), and right inferior longitudinal fasciculus (ILF). Step latency retention was associated with lower RD in the left posterior corona radiata and left PTR. Immediate improvements in AP MOS correlated with increased FA of the right ILF, right SLF, and right corticospinal tract. Immediate step length improvements were associated with increased FA in right and left ATR and right SLF. These findings highlight the importance of white-matter microstructural integrity in motor learning and retention processes in PD and could aid in identifying individuals with PD who would benefit most from balance rehabilitation.
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Affiliation(s)
- Andrew S Monaghan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, Atlanta, GA, USA
| | - Edward Ofori
- College of Health Solutions, Arizona State University, Phoenix, AZ, USA
| | - Brett W Fling
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
- Molecular, Cellular and Integrative Neurosciences Program, Colorado State University, Fort Collins, USA
| | - Daniel S Peterson
- College of Health Solutions, Arizona State University, Phoenix, AZ, USA.
- Phoenix VA Health Care Center, Phoenix, AZ, USA.
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Monaghan AS, Hooyman A, Dibble LE, Mehta SH, Peterson DS. Generalization of In-Place Balance Perturbation Training in People With Parkinson Disease. J Neurol Phys Ther 2024:01253086-990000000-00061. [PMID: 38489661 DOI: 10.1097/npt.0000000000000471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
BACKGROUND AND PURPOSE Reactive balance training improves reactive postural control in people with Parkinson disease (PwPD). However, the extent to which reactive balance training generalizes to a novel, unpracticed reactive balance task is unknown. This study aimed to determine whether reactive training stepping through support surface translations can be generalized to an unpracticed, instrumented tether-release task. METHODS Twenty-five PwPD (70.52 years ± 7.15; Hoehn and Yahr range 1-3) completed a multiple baseline, open-label, uncontrolled pre-post intervention study. Stepping was trained through a 2-week (6-session) intervention with repeated support surface translations. Performance on an untrained tether-release task (generalization task) was measured at 2 baseline assessments (B1 and B2, 2 weeks apart), immediately after the intervention (P1), and 2 months after training (P2). The tether-release task outcomes were the anterior-posterior margin of stability (MOS), step length, and step latency during backward and forward steps. RESULTS After support surface translation practice, tether-release stepping performance improved in MOS, step length, and step latency for both backward and forward steps compared to baseline (P < 0.05). Improvements in MOS and step length during backward and forward steps in the tether-release task, respectively, were related to stepping changes in the practiced task. However, the improvements in the generalization task were not retained for 2 months. DISCUSSION AND CONCLUSIONS These findings support short-term generalization from trained balance tasks to novel, untrained tasks. These findings contribute to our understanding of the effects and generalization of reactive step training in PwPD. Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content available at http://links.lww.com/JNPT/A465).
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Affiliation(s)
- Andrew S Monaghan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, Atlanta, Georgia (A.S.M.); School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona (A.H.); Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah (L.E.D.); Department of Neurology, Mayo Clinic, Scottsdale, Arizona (S.H.M.); College of Health Solutions, Arizona State University, Tempe, Arizona (D.S.P.); and Phoenix VA Health Care Center, Phoenix, Arizona (D.S.P.)
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Improvement of Balance, Motor Aspects, and Activities of Daily Living in Parkinson's Disease after a Sequential Multimodal Aquatic- and Land-Based Intervention Program. Rehabil Res Pract 2023; 2023:2762863. [PMID: 36654865 PMCID: PMC9842425 DOI: 10.1155/2023/2762863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 11/29/2022] [Accepted: 12/16/2022] [Indexed: 01/11/2023] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative, with heterogeneous clinical conditions and motor changes that reduce functioning. Postural instability is one of the motor aspects of disease progression, with a potential increase in the risk of falls, consequently affecting the activities of daily living (ADL). The objective of this study was to verify the influence of a multimodal intervention program (MIP) sequentially applied in aquatic- (AEs) and land-based environments (LEs) on balance, postural control, motor activities, and ADL in people with PD. It is an interventional clinical study with patients in stages 1 to 4 in the Hoehn and Yahr scale, assessed with Berg Balance Scale (BBS), Mini-Balance Evaluation System Test (Mini-BESTest), Unified Parkinson's Disease Rating Scale (UPDRS) II and III, Dynamic Gait Index (DGI), and quiet stance (QS) analysis in a force platform. The MIP was conducted sequentially with aquatic- (AIs) and land-based interventions (LIs) for 12 weeks each, twice a week, each session lasting 1 hour, and a 12-week interval between interventions. The comparison analysis was made with Friedman ANOVA, and the multiple comparisons with Wilcoxon signed-rank, Bonferroni correction, and effect size (r). The sample comprised 18 people with PD (66.83 ± 11.74 years). The AI and the full intervention (FI) had a large effect according to BBS. With Mini-BESTest, the LI and FI had a large effect. According to UPDRS II, the MIP improved ADL after LI, with a medium effect, and the motor aspects of UPDRS III improved after LI and FI, with a large effect. DGI was not sensitive in the analyses, with a ceiling effect after FI. No differences were identified in QS analyses. This research identified improved balance, ADL, and motor aspects in people with PD after sequential MIP in AI and LI, indicating that land-based and aquatic interventions are complementary and advantageous to people with PD.
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Cui Y, Yang W, Shuai J, Ma Y, Yan Y. High, low, and non-optimum temperatures exposure on road injuries in a changing climate: a secondary analysis based on the Global Burden of Disease Study 2019. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:11012-11024. [PMID: 36087177 DOI: 10.1007/s11356-022-22903-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
Global warming in the twenty-first century has gradually made high temperatures a major threat to the global population. Health problems associated with extreme temperatures have become a growing public health concern worldwide. This study aimed to estimate road injuries stratified by sex, age, geographic location, and sociodemographic status attribute to high, low, and non-optimal temperatures in 21 regional and global. We used the Global Burden of Disease (GBD) Study Results Tool to examine the age-standardized death rates (ASDR) and disability-adjusted life years (DALYs) due to road injuries in 2019 by Joinpoint regression. In addition, we reported high, low, and non-optimal temperature exposures for road injuries across different groups by gender, age, region, and disease. Moreover, we examined temporal trends in the burden of road disease caused by high, low, and non-optimum temperatures from 1990 to 2019. Trend analyzes were conducted for five sociodemographic index (SDI) regions. Globally, both ASDR and DALY declined from 1990 to 2019, with average annual percent change (AAPC) values of - 1.3% and - 1.2%, respectively. In 2019, the indicators (death and DALYs) steadily declined, while SDI quintile increased in most regions. Road injuries related to death and DALYs rate attributed to high temperatures were 0.17 and 8.50, respectively, in 2019. From 1990 to 2019, DALYs for road injuries caused by low temperatures showed the most significant upward trend in most regions, especially in low-latitude countries. This study provides a comprehensive understanding of the road injury burden caused by high, low, and non-optimum temperatures, which remains high in regions with low SDI. Therefore, special attention should be paid to road injuries in poor countries or in areas with extreme temperatures.
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Affiliation(s)
- Yiran Cui
- Department of Epidemiology and Medical Statistics, Xiangya School of Public Health, Central South University, Changsha, 410078, China
| | - Wenyan Yang
- Department of Epidemiology and Medical Statistics, Xiangya School of Public Health, Central South University, Changsha, 410078, China
| | - Jingliang Shuai
- Department of Epidemiology and Medical Statistics, Xiangya School of Public Health, Central South University, Changsha, 410078, China
| | - Yulan Ma
- Department of Epidemiology and Medical Statistics, Xiangya School of Public Health, Central South University, Changsha, 410078, China
| | - Yan Yan
- Department of Epidemiology and Medical Statistics, Xiangya School of Public Health, Central South University, Changsha, 410078, China.
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A type-2 neuro-fuzzy system with a novel learning method for Parkinson’s disease diagnosis. APPL INTELL 2022. [DOI: 10.1007/s10489-022-04276-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Conceição NRD, Nóbrega de Sousa P, Pereira MP, Gobbi LTB, Vitório R. Utility of center of pressure measures during obstacle crossing in prediction of fall risk in people with Parkinson’s disease. Hum Mov Sci 2019; 66:1-8. [PMID: 30889495 DOI: 10.1016/j.humov.2019.03.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 03/11/2019] [Accepted: 03/12/2019] [Indexed: 10/27/2022]
Abstract
INTRODUCTION Postural instability during walking and tripping over obstacles are the main causes of falls in people with Parkinson's disease (PD). Preliminary limited evidence suggests that the length of the prospective follow-up period affects falls prediction in PD, with shorter periods leading to more accurate prediction. Thus, the primary aim of the present study was to test the performance of center of pressure (CoP) variables during obstacle crossing to predict fall risk in people with PD during subsequent periods of four, six, and 12 months. We also compared CoP variables during obstacle crossing between fallers and non-fallers. METHODS Forty-two individuals with PD, in mild to moderate stages, completed the baseline obstacle crossing assessment and reported falls for 12 months. Participants walked at their self-selected pace and were instructed to cross an obstacle (half knee height) positioned in the middle of an 8-m long pathway. A force platform was used to analyze CoP parameters of the stance phase of the trailing limb (most affected limb). The ability of each outcome measure to predict fall risk at four, six, and 12 months was assessed using receiver operating characteristic curve analyses. RESULTS Ten individuals (23.8%) were considered fallers at four months, twelve individuals (28.5%) at six months, and twenty-one individuals (50%) at 12 months. CoP amplitude and CoP velocity in the mediolateral direction significantly predicted fall risk at four, six, and 12 months. As judged by the area under the curve, mediolateral CoP velocity showed the best performance at four months, while mediolateral CoP amplitude showed the best performance at six months. Fallers presented greater values of mediolateral CoP velocity and amplitude than non-fallers. CONCLUSION These findings suggest that mediolateral CoP velocity and amplitude during obstacle crossing might be useful to predict fall risk in people with PD. Therefore, larger studies are encouraged.
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Wright WG. Tonic Neuromuscular Processing Affects Postural Adaptation Differently in Aging and Parkinson's Disease. Front Neurol 2019; 9:1130. [PMID: 30719020 PMCID: PMC6348245 DOI: 10.3389/fneur.2018.01130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/10/2018] [Indexed: 11/13/2022] Open
Abstract
The combination of phasic and tonic neuromuscular processes are involved in the maintenance of normal upright posture. The latter is of particular importance in some pathologies, such as Parkinson's Disease (PD), which is known by one of its cardinal symptoms—tonic dysfunction (i.e., rigidity). Changes in tonic function may also occur during healthy aging. In this investigation, somatosensory input was manipulated by changing the support surface orientation for prolonged periods of quiet stance (QS). The aim was to shed light on how long-term tonic responses called postural lean after-effects are affected by aging and age-related neuropathology. Forty one participants were tested: 19 healthy young (25±5 years), 13 healthy older (63±8 years), and 9 adults with PD (63±5 years). Baseline conditions were eyes-closed QS on a stable surface or standing on an unstable, sway-referenced (SR) surface. Four experimental conditions combined two types of toes-up ramp tilt adaptation (120 s of toes-up static 7° tilt or sinusoidal 7° ± 3° tilt) with two types of post-adaptation (120 s of QS or SR). Results revealed postural after-effects during post-adaptation QS showing significant anterior COP shift for both young and older adults (p < 0.0001), but not PD (p > 0.06, n.s.). Compared to young, postural after-effects in older adults showed longer decay constants and did not return to baseline COP within the 120 s post-adaptation period (p < 0.05). Postural after-effects during SR, which appeared as toes-up surface tilt were highly significant in healthy populations (p = 0.001), but took longer to develop in PD. Younger adults showed significantly larger dorsiflexion (p < 0.01) and faster decay constants than older adults (p < 0.05). In summary, (1) postural after-effects decayed to baseline when post-tilt surface was stable but were retained and even grew larger post-adaptation in the SR surface conditions in all groups, (2) postural after-effects differed between healthy age groups, (3) PD showed less adaptation to surface changes. Differences in size and decay of after-effects between healthy and PD groups suggest tonic neuromuscular processes play a role in how adaptable postural control is to changing surface conditions and this is affected by healthy aging and basal ganglia function.
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Affiliation(s)
- W Geoffrey Wright
- Neuromotor Sciences Program, College of Public Health, Temple University, Philadelphia, PA, United States
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Khoury N, Attal F, Amirat Y, Oukhellou L, Mohammed S. Data-Driven Based Approach to Aid Parkinson's Disease Diagnosis. SENSORS (BASEL, SWITZERLAND) 2019; 19:E242. [PMID: 30634600 PMCID: PMC6359125 DOI: 10.3390/s19020242] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 01/03/2019] [Accepted: 01/04/2019] [Indexed: 11/22/2022]
Abstract
This article presents a machine learning methodology for diagnosing Parkinson's disease (PD) based on the use of vertical Ground Reaction Forces (vGRFs) data collected from the gait cycle. A classification engine assigns subjects to healthy or Parkinsonian classes. The diagnosis process involves four steps: data pre-processing, feature extraction and selection, data classification and performance evaluation. The selected features are used as inputs of each classifier. Feature selection is achieved through a wrapper approach established using the random forest algorithm. The proposed methodology uses both supervised classification methods including K-nearest neighbour (K-NN), decision tree (DT), random forest (RF), Naïve Bayes (NB), support vector machine (SVM) and unsupervised classification methods such as K-means and the Gaussian mixture model (GMM). To evaluate the effectiveness of the proposed methodology, an online dataset collected within three different studies is used. This data set includes vGRF measurements collected from eight force sensors placed under each foot of the subjects. Ninety-three patients suffering from Parkinson's disease and 72 healthy subjects participated in the experiments. The obtained performances are compared with respect to various metrics including accuracy, precision, recall and F-measure. The classification performance evaluation is performed using the leave-one-out cross validation. The results demonstrate the ability of the proposed methodology to accurately differentiate between PD subjects and healthy subjects. For the purpose of validation, the proposed methodology is also evaluated with an additional dataset including subjects with neurodegenerative diseases (Amyotrophic Lateral Sclerosis (ALS) and Huntington's disease (HD)). The obtained results show the effectiveness of the proposed methodology to discriminate PD subjects from subjects with other neurodegenerative diseases with a relatively high accuracy.
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Affiliation(s)
- Nicolas Khoury
- Laboratory of Images, Signals and Intelligent Systems (LISSI), University of Paris-Est Créteil (UPEC), 122 rue Paul Armangot, 94400 Vitry-Sur-Seine, France.
| | - Ferhat Attal
- Laboratory of Images, Signals and Intelligent Systems (LISSI), University of Paris-Est Créteil (UPEC), 122 rue Paul Armangot, 94400 Vitry-Sur-Seine, France.
| | - Yacine Amirat
- Laboratory of Images, Signals and Intelligent Systems (LISSI), University of Paris-Est Créteil (UPEC), 122 rue Paul Armangot, 94400 Vitry-Sur-Seine, France.
| | - Latifa Oukhellou
- French Institute of Science and Technology for Transport, Development and Networks (IFSTTAR), University of Paris-Est, COSYS, GRETTIA, F-77447 Marne la Vallée, France.
| | - Samer Mohammed
- Laboratory of Images, Signals and Intelligent Systems (LISSI), University of Paris-Est Créteil (UPEC), 122 rue Paul Armangot, 94400 Vitry-Sur-Seine, France.
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Functional Improvements in Parkinson's Disease Following a Randomized Trial of Yoga. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 2018:8516351. [PMID: 29967649 PMCID: PMC6009016 DOI: 10.1155/2018/8516351] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/24/2018] [Indexed: 12/02/2022]
Abstract
Individuals with Parkinson's Disease (PD) experience significant limitations in motor function, functional gait, postural stability, and balance. These limitations often lead to higher incidences of falls, which have significant complications for individuals with PD. Yoga may improve these functional deficits in individuals with PD. The objective of this study was to determine changes in motor function, functional gait, postural stability, and balance control for community dwelling individuals with PD. This randomized, wait-list controlled pilot study examined the influence of an 8-week yoga intervention for people with PD who met the following inclusion criteria: endorsing a fear of falling, being able to speak English, scoring 4/6 on the minimental state exam, and being willing to attend the intervention twice weekly for 8-weeks. Participants in the yoga group (n=15) experienced improvements in motor function, postural stability, functional gait, and freezing gait, as well as reductions in fall risk. Participants in the wait-list control (n=12) also significantly improved in postural stability, although their fall risk was not reduced. Individuals in the yoga group significantly reduced their fall risk. An 8-week yoga intervention may reduce fall risk and improve postural stability, and functional and freezing gait in individuals with PD. This clinical trial is registered as protocol record Pro00041068 in clinicaltrials.gov.
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Debû B, De Oliveira Godeiro C, Lino JC, Moro E. Managing Gait, Balance, and Posture in Parkinson's Disease. Curr Neurol Neurosci Rep 2018; 18:23. [PMID: 29623455 DOI: 10.1007/s11910-018-0828-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
PURPOSE OF REVIEW Postural instability and gait difficulties inexorably worsen with Parkinson's disease (PD) progression and become treatment resistant, with a severe impact on autonomy and quality of life. We review the main characteristics of balance instability, gait disabilities, and static postural alterations in advanced PD, and the available treatment strategies. RECENT FINDINGS It remains very difficult to satisfactorily alleviate gait and postural disturbances in advanced PD. Medical and surgical interventions often fail to provide satisfactory or durable alleviation of these axial symptoms, that may actually call for differential treatments. Exercise and adapted physical activity programs can contribute to improving the patients' condition. Gait, balance, and postural disabilities are often lumped together under the Postural Instability and Gait Difficulties umbrella term. This may lead to sub-optimal patients' management as data suggest that postural, balance, and gait problems might depend on distinct underlying mechanisms. We advocate for a multidisciplinary approach from the day of diagnosis.
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Affiliation(s)
- Bettina Debû
- University Grenoble Alpes, Grenoble, France.
- INSERM U1216, Grenoble, France.
| | - Clecio De Oliveira Godeiro
- INSERM U1216, Grenoble, France
- Movement Disorders Unit, Division of Neurology, CHU Grenoble Alpes, Grenoble, France
- Division of Neurology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Jarbas Correa Lino
- INSERM U1216, Grenoble, France
- Movement Disorders Unit, Division of Neurology, CHU Grenoble Alpes, Grenoble, France
- Division of Neurology, CHU Amiens, Amiens, France
| | - Elena Moro
- University Grenoble Alpes, Grenoble, France
- INSERM U1216, Grenoble, France
- Movement Disorders Unit, Division of Neurology, CHU Grenoble Alpes, Grenoble, France
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Di Giulio I, St George RJ, Kalliolia E, Peters AL, Limousin P, Day BL. Maintaining balance against force perturbations: impaired mechanisms unresponsive to levodopa in Parkinson's disease. J Neurophysiol 2016; 116:493-502. [PMID: 27098030 PMCID: PMC4978787 DOI: 10.1152/jn.00996.2015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 04/20/2016] [Indexed: 11/22/2022] Open
Abstract
We introduce a new method to investigate postural instability in Parkinson's disease (PD) using computer-controlled motors to deliver precise pulls to the shoulders of subjects while standing. It mimics the clinical pull test but uses forces with unpredictable timing, direction, and magnitude. It revealed a number of balance control deficits in PD. Notably, the identified deficits were not significantly altered by levodopa medication, suggesting that disruption to nondopaminergic systems contributes to postural instability in PD. There is evidence that postural instability associated with Parkinson's disease (PD) is not adequately improved by levodopa, implying involvement of nondopaminergic pathways. However, the mechanisms contributing to postural instability have yet to be fully identified and tested for their levodopa responsiveness. In this report we investigate balance processes that resist external forces to the body when standing. These include in-place responses and the transition to protective stepping. Forward and backward shoulder pulls were delivered using two force-feedback-controlled motors and were randomized for direction, magnitude, and onset. Sixteen patients with PD were tested OFF and ON levodopa, and 16 healthy controls were tested twice. Response behavior was quantified from 3-dimensional ground reaction forces and kinematic measurements of body segments and total body center-of-mass (CoM) motion. In-place responses resisting the pull were significantly smaller in PD as reflected in reduced horizontal anteroposterior ground reaction force and increased CoM displacement. Ankle, knee, and hip moments contributing to this resistance were smaller in PD, with the knee extensor moment to backward pulls being the most affected. The threshold force needed to evoke a step was also smaller for PD in the forward direction. Protective steps evoked by suprathreshold pulls showed deficits in PD in the backward direction, with steps being shorter and more steps being required to arrest the body. Levodopa administration had no significant effect on either in-place or protective stepping deficits. We conclude that processes employed to maintain balance in the face of external forces show impairment in PD consistent with disruption to nondopaminergic systems.
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Affiliation(s)
- Irene Di Giulio
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Rebecca J St George
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom; School of Medicine, University of Tasmania, Hobart, Australia; and
| | - Eirini Kalliolia
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom; St. Luke's Hospital, Thessaloniki, Greece
| | - Amy L Peters
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Patricia Limousin
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Brian L Day
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom;
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