Trunk stabilization estimated using pseudorandom force perturbations, a reliability study

Griffioen, M.; Maaswinkel, E.; Zuurmond, W. W. A.; Dieën, Jaap H. van; Pérez, Roberto

doi:10.1016/j.jbiomech.2015.12.007

Cited by 7 publications

(8 citation statements)

References 44 publications

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“…In infants, RMS sway was not significantly different between the start and end of each testing period, consistent with adult data and previous studies [22,34]. Infants and children with CP also exhibited similar trends in frequency response functions curves.…”

Section: Discussionsupporting

confidence: 90%

“…It would be valuable to also use a perturbation to directly evoke sway in the sagittal plane. A visual stimulus could be incorporated into the current trunk support configuration; however, a significant redesign would be required to deliver a surface perturbation [34]. We also note that our qualitative assessment of comfort may benefit from the creation of a standardized assessment.…”

Section: Discussionmentioning

confidence: 99%

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A Trunk Support System to Identify Posture Control Mechanisms in Populations Lacking Independent Sitting

Goodworth

Felmlee

et al. 2017

IEEE Trans. Neural Syst. Rehabil. Eng.

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Populations with moderate-to-severe motor control impairments often exhibit degraded trunk control and/or lack the ability to sit unassisted. These populations need more research, yet their underdeveloped trunk control complicates identification of neural mechanisms behind their movements. The purpose of this study was to overcome this barrier by developing the first multi-articulated trunk support system to identify visual, vestibular, and proprioception contributions to posture in populations lacking independent sitting. The system provided external stability at a user-specific level on the trunk, so that body segments above the level of support required active posture control. The system included a tilting surface (controlled via servomotor) as a stimulus to investigate sensory contributions to postural responses. Frequency response and coherence functions between the surface tilt and trunk support were used to characterize system dynamics and indicated that surface tilts were accurately transmitted up to 5Hz. Feasibility of collecting kinematic data in participants lacking independent sitting was demonstrated in two populations: two typically developing infants, ~2-8 months, in a longitudinal study (8 sessions each) and four children with moderate-to-severe cerebral palsy (GMFCS III-V). Adaptability in the system was assessed by testing 16 adults (ages 18-63). Kinematic responses to continuous pseudorandom surface tilts were evaluated across 0.046–2Hz and qualitative feedback indicated that the trunk support and stimulus were comfortable for all subjects. Concepts underlying the system enable both research for, and rehabilitation in, populations lacking independent sitting.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

A Trunk Support System to Identify Posture Control Mechanisms in Populations Lacking Independent Sitting

Goodworth

Felmlee

et al. 2017

IEEE Trans. Neural Syst. Rehabil. Eng.

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“…The method used was proven reliable [28] and the reader is referred to previous publications for a detailed description of the procedure and related analyses [29,30]. In short, participants were positioned in a kneeling-seated position with their pelvis fixed (Fig 3).…”

Section: Methodsmentioning

confidence: 99%

Prolonged Intermittent Trunk Flexion Increases Trunk Muscles Reflex Gains and Trunk Stiffness

et al. 2016

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The goal of the present study was to determine the effects of prolonged, intermittent flexion on trunk neuromuscular control. Furthermore, the potential beneficial effects of passive upper body support during flexion were investigated. Twenty one healthy young volunteers participated during two separate visits in which they performed 1 hour of intermittent 60 seconds flexion and 30 seconds rest cycles. Flexion was set at 80% lumbar flexion and was performed with or without upper body support. Before and after intermittent flexion exposure, lumbar range of motion was measured using inertial measurement units and trunk stability was assessed during perturbations applied in the forward direction with a force controlled actuator. Closed-loop system identification was used to determine the trunk translational admittance and reflexes as frequency response functions. The admittance describes the actuator displacement as a function of contact force and to assess reflexes muscle activation was related to actuator displacement. Trunk admittance gain decreased after unsupported flexion, while reflex gain and lumbar range of motion increased after both conditions. Significant interaction effects confirmed a larger increase in lumbar range of motion and reflex gains at most frequencies analysed following unsupported flexion in comparison to supported flexion, probably compensating for decreased passive tissue stiffness. In contrast with some previous studies we found that prolonged intermittent flexion decreased trunk admittance, which implies an increase of the lumped intrinsic and reflexive stiffness. This would compensate for decreased stiffness at the cost of an increase in cumulative low back load. Taking into account the differences between conditions it would be preferable to offer upper body support during activities that require prolonged trunk flexion.

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Section: Introductionmentioning

confidence: 99%

“…We have recently developed a method to assess intrinsic and reflexive contributions to trunk stabilization, which aims to circumvent the limitations described above [8][9][10]. The method was shown to have good reliability in healthy subjects and LBP patients [9]. The present study used this method to assess differences in trunk stabilization between LBP patients and healthy controls when maximally resist the perturbation or when sitting relaxed but upright, to investigate their maximal ability, natural behavior and their ability to modulate between both tasks.…”

Section: Introductionmentioning

confidence: 99%

Identification of intrinsic and reflexive contributions to trunk stabilization in patients with low back pain: a case–control study

et al. 2020

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Purpose The goal of this study was to assess differences in low back stabilization and underlying mechanisms between patients with low back pain (LBP) and healthy controls. It has been hypothesized that inadequate trunk stabilization could contribute to LBP through high tissue strains and/or impingement. Evidence to support this is inconsistent, and not all methods that have been used to study trunk stabilization are equally suitable. We have recently developed a method to assess intrinsic and reflexive contributions to trunk stabilization, which aims to circumvent the limitations of previous studies. Methods Forty-nine participants suffering from chronic LBP and a control group of fifty healthy subjects participated in this study. Trunk stabilization was measured using force-controlled perturbations directly applied to the trunk. The actuator displacement and contact force between the actuator and subject were measured as well as electromyography (EMG) of the M. Longissimus. Underlying mechanisms were characterized using system identification. Results LBP patients showed lower admittance, i.e., less displacement per unit of force applied, mainly due to higher position, velocity and acceleration feedback gains. Among patients, lower trunk admittance and higher reflex gains were associated with more negative pain-related cognitions. Conclusion Trunk stabilization differs between LBP patients and controls, with the same perturbations causing less trunk movement in patients, due to stronger reflexes. We interpret these changes as reflecting protective behavior.

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Trunk stabilization estimated using pseudorandom force perturbations, a reliability study

Cited by 7 publications

References 44 publications

A Trunk Support System to Identify Posture Control Mechanisms in Populations Lacking Independent Sitting

A Trunk Support System to Identify Posture Control Mechanisms in Populations Lacking Independent Sitting

Prolonged Intermittent Trunk Flexion Increases Trunk Muscles Reflex Gains and Trunk Stiffness

Identification of intrinsic and reflexive contributions to trunk stabilization in patients with low back pain: a case–control study

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