Bimanual Motor Impairments in Patients with Parkinson’s Disease

다국어 초록 (Multilingual Abstract)

Parkinson’s disease is a neurological disorder that causes motor symptoms such as
tremor, rigidity, and bradykinesia. In the early stages of Parkinson’s disease, motor
symptoms may occur asymmetrically, and patients may experience deficits on bimanual
force control capability and bimanual coordination. The purpose of this study was to
investigate motor impairments in patients with PD by using an isometric force control
paradigm for fine motor control assessment, such as bimanual force control capabilities
and bimanual force coordination. 33 patients with early stage PD and 33 age matched
healthy older adults were recruited to estimate bimanual force control capabilities,
bimanual force coordination, bimanual force control asymmetry and bimanual motor
dexterity. To evaluate bimanual force control capabilities, bimanual isometric force
control task was conducted at target force levels at 10% and 40%MVC, based on each
individual's maximum voluntary contraction (MVC). The analysis included assessments of
mean force, accuracy, variability, and regularity. For assessing bimanual coordination,
within-trial analyses included the coefficient of variation and cross-correlation, and
between-trial analyses using uncontrolled manifold analysis were conducted. Additionally,
to assess bimanual motor dexterity in patients with Parkinson's disease, bimanual
Pegboard tasks were conducted. The result indicated that PD group showed lower mean
force, lower force accuracy, higher force variability and higher force regularity in
bimanual force control capabilities. Additionally, PD group exhibited lower bimanual
Pegboard test scores on bimanual motor dexterity. For bimanual force coordination, PD
group revealed lower bilateral motor synergy as compared with CON group. Further,
negative correlations were found between bimanual force control capabilities and
UPDRS-III subscores, bimanual coordination and UPDRS-III subscores, and bimanual
dexterity scores and UPDRS-III subscores for correlation analyses. These findings
suggest that early and precise assessment of fine motor control may be crucial for
developing potential rehabilitation protocols in patients with early stage of PD.

국문 초록 (Abstract)

파킨슨병 환자들의 양손 운동기능 손상 파킨슨병은 중추신경계 질환으로 뇌의 흑색질 부위에 존재하는 신경세포의 사멸 로 도파민의 생성이 정상적으로 되지 않음으로 인해 파킨슨병 운동증상(예: 떨림, 강직성, 완만증, 자세유지 및 걸음걸이 장애)이 발생한다. 초기 단계의 파칸슨병 운 동증상은 편측성으로 발생하게 되며, 파킨슨병 환자들의 힘조절 능력에 있어 대칭 성이 무너질 수 있다. 운동 비대칭성은 양측이 동반되는 협응성이 요구되는 동작의 저하로 이어지게 되며 양손 힘조절능력 및 이와 연관된 양손 협응성 저하가 발생할 수 있다. 본 연구의 목적은 등척성 힘조절 패러다임을 통해 파킨슨병 환자들의 양 손 힘조절능력 및 협응성과 연관된 운동손상을 평가하는 데 있다. 이를 위해 초기 단계에 해당하는 파킨슨병 환자 33명, 건강한 노인 33명을 대상으로 양손 힘조절능 력, 양손 협응성 및 양손 손재주를 평가하였다. 양손 힘조절능력을 평가하기 위해 개인 악력의 최대 자발적 수축(maximum voluntary contraction; MVC)의 측정을 이용 한 개인이 힘조절을 통해 도달해야 될 목표 힘수준의 생성 10%MVC 및 40%MVC 에 따른 등척성 힘조절 과제를 실시하여 평균 힘, 정확성, 가변성, 규칙성을 분석하 였다. 양손 협응성을 평가하기 위해 시도 내 분석에 해당하는 변동계수, 상호상관성 그리고 시도 간 분석인 비제어다양체 분석을 실시했다. 또한, 파킨슨병 환자들의 양 손 손재주를 평가하기 위해 팩보드를 이용한 양손 손재주 점수를 평가하였다. 추가 적으로 양손 힘조절능력, 손재주 및 임상 운동성 평가 점수 간 상관관계를 각각 분 석하였다. 연구결과, 파킨슨병 환자의 양손 힘조절능력에서 낮은 힘 정확성, 높은 힘 가변성, 높은 힘 규칙성이 나타났으며 양손 손재주 평가 점수의 경우 대조군과 비교하여 낮게 나타났다. 양손 협응성 변인에서 낮은 양측운동시너지가 나타났다. 또한, 상관관계 분석결과에서 양손 힘조절능력 변인 및 임상 운동성 평가 점수 간 음의 상관관계, 양손 협응성 및 임상 운동성 평가 점수 간 음의 상관관계, 그리고 양손 손재주 점수 및 임상 운동성 평가 점수 간 음의 상관관계가 나타났다. 이러한 결과로써 초기 단계 파킨슨병 환자의 미세 힘조절과 연관된 운동손상 평가는 중요 하며, 이와 연관된 재활프로토콜 개발에 있어 필수적인 기초자료가 될 수 있다. 주제어: 파킨슨병, 양손 힘조절능력, 양손 협응성, 손재주 평가, 임상 운동성 평가

목차 (Table of Contents)

• Abstract ⅰ
• Table of contents ii
• List of tables v
• List of figures vi
• 1. Introduction 1
• 1.1. Aim of the study 4
• 1.2. Hypotheses 4
• 1.3. Definitions 6
• 2. Literature review 7
• 2.1. Parkinson’s disease and motor symptoms 7
• 2.2. Upper-limb motor functions in Parkinson’s disease 9
• 2.3. Asymmetric neural impairments in Parkinson’s disease 13
• 2.4. Unimanual motor deficits in Parkinson’s disease 14
• 2.5. Potential bimanual motor deficits in Parkinson’s disease 16
• 3. Methods 18
• 3.1. Ethical statements 18
• 3.2. Participants 18
• 3.3. Experimental equipment 19
• 3.4. Experimental procedures 21
• 3.5. Data analyses 25
• 3.6. Statistical analyses 32
• 4. Results 34
• 4.1. Bimanual force control capabilities 34
• 4.2. Bimanual force coordination 43
• 4.3. Bimanual force control asymmetry 48
• 4.4. Bimanual motor dexterity 54
• 4.5. Correlation between bimanual force control capabilities and
• Unified Parkinson’s Disease Rating Scale-Part 3 (UPDRS-III)
• subscore 56
• 4.6. Correlation between bimanual force coordination and
• UPDRS-III subscore 62
• 4.7. Correlation between bimanual motor dexterity and UPDRS-III
• subscore 68
• 5. Discussion 71
• 5.1. Impaired bimanual force control capabilities in patients
• with Parkinson’s disease 72
• 5.2. Bimanual force coordination and force control asymmetry
• in patients with Parkinson’s disease 75
• 5.3. Impaired bilateral motor synergy in patients with
• Parkinson’s disease: uncontrolled manifold approach 77
• 5.4. Impaired bimanual motor dexterity in patients with
• Parkinson’s disease 79
• 5.5. Relation between rigidity and bimanual force control
• capabilities 80
• 5.6. Relation between rigidity, bradykinesia, and bimanual
• force coordination 81
• 5.7. Relation between rigidity, bradykinesia, and bimanual
• motor dexterity 82
• 5.8. Limitations 83
• 6. Conclusion 85
• References 86

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