Linear and Non-linear Dynamic Methods Toward Investigating Proprioception Impairment in Non-specific Low Back Pain Patients

Seyed Mohammadreza Shokouhyan; Mehrdad Davoudi; Maryam Hoviattalab; Mohsen Abedi; Soha Bervis; Mohamad Parnianpour; Simon Brumagne; Kinda Khalaf

doi:10.3389/fbioe.2020.584952

Linear and Non-linear Dynamic Methods Toward Investigating Proprioception Impairment in Non-specific Low Back Pain Patients

Front Bioeng Biotechnol. 2020 Nov 30:8:584952. doi: 10.3389/fbioe.2020.584952. eCollection 2020.

Authors

Seyed Mohammadreza Shokouhyan¹, Mehrdad Davoudi¹, Maryam Hoviattalab¹, Mohsen Abedi², Soha Bervis^{3

4}, Mohamad Parnianpour¹, Simon Brumagne⁵, Kinda Khalaf⁶

Affiliations

¹ Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran.
² Physiotherapy Research Center, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
³ Physical Therapy Department, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
⁴ Rehabilitation Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
⁵ Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
⁶ Healthcare Engineering Innovation Center, Department of Biomedical Engineering, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates.

Abstract

Central nervous system (CNS) uses vision, vestibular, and somatosensory information to maintain body stability. Research has shown that there is more lumbar proprioception error among low back pain (LBP) individuals as compared to healthy people. In this study, two groups of 20 healthy people and 20 non-specific low back pain (NSLBP) participants took part in this investigation. This investigation focused on somatosensory sensors and in order to alter proprioception, a vibrator (frequency of 70 Hz, amplitude of 0.5 mm) was placed on the soleus muscle area of each leg and two vibrators were placed bilaterally across the lower back muscles. Individuals, whose vision was occluded, were placed on two surfaces (foam and rigid) on force plate, and trunk angles were recorded simultaneously. Tests were performed in eight separate trials; the independent variables were vibration (four levels) and surface (two levels) for within subjects and two groups (healthy and LBP) for between subjects (4 × 2 × 2). MANOVA and multi-factor ANOVA tests were done. Linear parameters for center of pressure (COP) [deviation of amplitude, deviation of velocity, phase plane portrait (PPP), and overall mean velocity] and non-linear parameters for COP and trunk angle [recurrence quantification analysis (RQA) and Lyapunov exponents] were chosen as dependent variables. Results indicated that NSLBP individuals relied more on ankle proprioception for postural stability. Similarly, RQA parameters for the COP on both sides and for the trunk sagittal angle indicated more repeated patterns of movement among the LBP cohort. Analysis of short and long Lyapunov exponents showed that people with LBP caused no use of all joints in their bodies (non-flexible), are less stable than healthy subjects.

Keywords: COP; low back pain; posture control; proprioception; recurrence quantification analyses; vibrator.