||Comparison of neck position sense, balance control, and forward reach performance between neck pain patients and pain-free controls
||Department of Physical Therapy
pressure pain threshold
neck position sense
方法:二十位慢性頸痛患者(24.1 ± 3.4歲, 14女6男)與二十位健康受試者(23.7 ± 3.3歲, 14女6男)參與本實驗。而頸痛組會接受誘發頸痛的任務，維持頸部屈曲的姿勢使用平板電腦。頸痛組在誘發頸痛任務前與後以及健康受試者會以組織硬度測量儀(tissue hardness meter)及痛覺計(algometer)量化肩頸組織硬度和壓痛閾值。兩組受試者會進行頸部本體感覺測試、前伸測試以及平衡表現，而只有十二位頸痛患者在誘發頸痛任務之前進行測試。頸部本體感覺測試為原點再定位，包括頸屈曲、頸伸展以及左右轉後再回到自己認為的起始位置。而平衡測試分別評估睜眼與閉眼在雙腳合併站(Romberg stance)、雙腳前後站(Tandem stance)和單腳站(single leg stance)。另外，前伸測試為上肢舉至水平面並向前伸至最遠。
結果:頸痛組在雙側枕下肌(p<.01)、斜方肌(p<.01)和提胛肌(p<.01)都有較高的組織硬度和較低的壓痛閾值。在頸部本體感覺測試中，三個狀況(頸痛組在誘發頸痛前、誘發頸痛後以及健康受試者)的絕對誤差(absolute error)有明顯差異，包括屈曲回起始位置(flexion to initial)動作的冠狀面上(F=3.718, p=0.031)、伸展回起始位置(extension to initial)的矢狀面上(F=3.384, p=0.042)、右轉回起始位置的冠狀面上(F=5.475, p<0.01)以及左轉回起始位置的矢狀面上(F=5.95, p<0.01) 。另外，三個狀況(頸痛組在誘發頸痛前、誘發頸痛後以及健康受試者)的變異誤差(variable error)有明顯差異，包括右轉回正中的橫狀面上(F=3.323, p=0.044) 。而在均方根誤差中(root mean square error) ，三個狀況(頸痛組在誘發頸痛前、誘發頸痛後以及健康受試者)在屈曲回正中動作的冠狀面上(F=3.698, p=0.032)、右轉回正中的冠狀面上(F=4.522, p=0.016)、左轉回正中的矢狀面(F=5.405, p<0.01)和橫狀面上(F=3.261, p=0.047)有明顯差異。在平衡任務中，與控制組相比，頸痛組在誘發頸痛後在雙腳合併站(Romberg stance)(p=0.04)張眼時與雙腳前後站(Tandem stance)(p=0.004)張眼時有較大的壓力中心晃動面積(COP sway area) 。在前伸測試中，質心(COM)(F=5.89, p=0.004)與壓力中心(COP)(F=4.98, p=0.009)向前位移有明顯的組間效應(group effects)，而前伸距離(F=4.96, p=0.028)與肩峰鎖骨關節向前位移(F=13.4, p<.001)有明顯的疼痛效應(pain effects)。
結論:頸部疼痛、肌肉僵硬以及關節失能都可能會干擾頸部本體感覺，進而造成平衡能力受損。另外，頸痛患者前伸距離較健康組短，並會使用手固定(fixed arm strategy)策略(較小的肩峰鎖骨關節向前位移)來完成前伸測試。相反地，控制組有較好的質心向前位移能力，並且可利用較多的上半身動作來達到較遠的距離。
Background: The myofascial pain in the neck and shoulder regions are major cause of mechanical neck pain. Prolonged awkward posture or inappropriate ergonomics may lead to neck myofascial pain with taut bands in muscles. The neck proprioception is mainly controlled by the muscles with high density concentrations of muscle spindles. The proprioceptive information from cervical region links to the whole body via a proprioceptive chain, thus may have direct effect on balance or postural control. Besides, forward reach is composed of chin out and shoulder flexion, and thus requires greater activation of neck extensors. Therefore, the forward reach test may challenge the ability of dynamic balance control in the neck pain patients. The purpose of this study was to compare the neck tissue hardness, pressure pain threshold, neck position sense, electromyography of neck muscles, balance control, and forward reach performance between the patients with mechanical neck pain and the healthy controls. The other purpose is to discuss the relationship between neck position sense and balance control.
Methods: Twenty subjects with chronic neck pain (24.1 ± 3.4years, 14F6M) and twenty age-matched healthy controls (23.7 ± 3.3years, 14F6M) participated in this study. The neck pain group received reproduced pain protocol by playing the tablet in sustained neck flexed posture. The tissue hardness and pressure pain threshold were measured in neck pain group before and after pain-induced and in the controls. Both groups were asked to perform the cervical kinesthetic sensibility test, forward reach test, and balance tasks. There were twelve subjects with chronic neck pain performing the tests before pain-induced. The neck proprioception test requires the subjects to relocate the neutral head position after active neck flexion, extension, left and right rotation with eyes closed. The balance tasks were performed with eyes open and eyes closed conditions. Furthermore, the forward reach test was to measure the maximal distance by reaching forward without stepping forward or losing balance.
Results: The neck pain group demonstrated harder tissue status and lower pressure pain threshold before and after pain-induced than control group in bilateral suboccipital (p<.01), upper trapezius (p<.01) and levator scapulae (p<.01) muscles. In the cervical kinesthetic sensibility test, there were significant differences between the three conditions (neck pain group before pain-induced vs neck pain group after pain-induced vs control) on absolute error of flexion to neutral in the frontal plane (F=3.718, p=0.031), extension to neutral in the sagittal plane (F=3.384, p=0.042), right rotation to neutral in the frontal plane (F=5.475, p<0.01), and left rotation to neutral in the sagittal plane (F=5.95, p<0.01). Besides, there were significant differences on variable error of right rotation to neutral in the transverse plane (F=3.323, p=0.044), and root mean square error of flexion to neutral in the frontal plane (F=3.698, p=0.032), right rotation to neutral in the frontal plane (F=4.522, p=0.016), left rotation to neutral on sagittal plane (F=5.405, p<0.01), and left rotation to neutral in the transverse plane (F=3.261, p=0.047). In the balance tasks, the COP sway area for neck pain group were greater than those in control group in Romberg stance with eyes-open (p=0.04) and Tandem stance with eyes-open (p=0.004). In forward reach test, there were significant group effect (neck pain before pain-induced vs. neck pain after pain-induced vs. control) on COM forward displacement (F=5.89, p=0.004) and COP forward displacement (F=4.98, p=0.009). In addition, significant pain effect was also found on reach distance (F=4.96, p=0.028) and ACJ displacement (F=13.4, p<.001).
Conclusions: The muscle pain, muscle spasm, and joint dysfunction may influence the perception of neck position, and thus give rise to deficit in standing balance . In addition, patients with neck pain achieved lesser distance with the fixed arm strategy (less acromioclavicular joint displacement) during forward reach. Conversely, the control group had better capacity of moving the COM forward to achieve greater distance primarily by increasing the upper body movement.
Chapter1 Background 1
1.1 Research purpose 4
1.2 Research questions 4
Chapter 2 Literature review 6
2.1 Epidemiology and risk factors of neck pain 6
2.2 Neck pain and neck position sense 10
2.2.1 Muscle spindles sensitivity 10
2.2.2 Neck position error 12
2.2.3 Co-contraction index 13
2.3 Neck pain and static balance 15
2.3.1 Cervicogenic vertigo – Neck torsion test 16
2.4 Neck pain and dynamic balance – forward reach test 18
2.4.1 The contribution of neck to forward reaching 18
2.4.2 Functional reach test and balance strategy 18
2.4.3 Dominant arm 19
Chapter 3 Methods 21
3.1 Subjects 21
3.2 Instrumentations 22
3.2.1 Maker Placement 22
3.2.2 Electromyography Arrangement 23
3.3 Experimental Procedure 25
3.3.1 Questionnaire 27
3.3.2 Physical examination 28
3.3.3 Neck muscle hardness and pressure pain threshold 30
3.3.4 Reproduce protocol 31
3.3.5 Cervical kinesthetic sensibility test 31
3.3.6 Static balance tasks and standing posture 32
3.3.7 Forward reach test 33
3.4 Data reduction 35
3.4.1 Parameters 35
3.4.2 Phase definition 40
3.4.3 Dependent variables of forward reach test (Table3-1)41
3.5 Statistic analysis 42
Chapter 4 Result 43
4.1 Demographics 43
4.2 Questionnaire 49
4.2.1 Visual analogue scale (VAS) 50
4.3 Anthropometry measurement 53
4.4 Tissue Hardness and pressure pain threshold 55
4.5 Cervical kinesthetic sensibility test 58
4.5.1 Joint position error 58
4.6 Posture 71
4.7 Forward reach test 72
4.7.1 Kinematics and kinetics 72
4.8 Balance 82
4.8.1 COP parameters 82
Chapter 5 Discussion 93
5.1 Muscle strength and range of motion 93
5.2 Cranio-cervical flexion test 95
5.3 Tissue hardness 97
5.4 Pressure pain threshold 100
5.5 Posture 104
5.6 Cervical kinesthetic sensibility test 108
5.6.1 Neck position sense 108
5.7 Balance 122
5.7.1 COP parameters 122
5.8 Forward reach 130
5.8.1 Kinematics and kinetics 130
5.9 Limitation 137
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