Postural adaptations within normalized stability between older adults with and without chronic low back pain

Sensory integration strategies on repeated postural stability and neuromuscular adaptation in individuals with low back pain

BACKGROUND

Individuals with low back pain (LBP) often exhibit balance impairments resulting from altered neuromuscular control and sensory integration deficits.

PURPOSE

This study aimed to compare differences in sway excursion and neuromuscular responses in maintaining spatial orientation and equilibrium between adults with and without LBP under eyes-open and eyes-closed conditions.

METHODS

Thirty-two adults with LBP and 40 control subjects performed three repeated trials of unilateral standing tasks on a force platform. Center of pressure (COP) displacement on anteroposterior (AP) and mediolateral (ML) directions, center of gravity (COG), and COP-COG displacement were analyzed to assess postural stability and neuromuscular responses.

RESULTS

For COP sway excursion, significant group interactions were observed between visual condition and repetition (F(2, 136) = 4.03, p < 0.05). Neuromuscular responses, assessed by COP-COG displacement, demonstrated significant group interactions across visual condition (F(1, 68) = 7.19, p < 0.01), repetition (F(2, 136) = 4.26, p < 0.05), and the combined effect of visual condition and direction (F(1, 68) = 8.15, p < 0.01). In the LBP group, neuromuscular response increased significantly in both eyes-open (t = -1.84, p < 0.05) and eyes-closed (t = 2.16, p < 0.05) conditions during the third trial in the ML direction.

CONCLUSION

These findings suggest that individuals with LBP exhibit distinct sway excursions under eyes-open conditions, but do not when their eyes are closed. The control group relied more on vision to maintain balance than the LBP group, who appeared to struggle with balance regulation independent of visual cues.

The role of life-space mobility in the relationship of chronic low back pain characteristics with falls and cognitive impairment

Chronic pain contributes to both physical and cognitive impairment, but the role of life-space mobility (LSM) in the pathway is unclear. We examined the cross-sectional association of pain with falls and mild cognitive impairment (MCI) and explored whether LSM mediates these associations in 279 Veterans (mean age=73.3±5.0y) in the Aging Back Clinics trial with chronic low back pain (CLBP). Data on pain characteristics, falls during the prior 3 months, Quick MCI screen, and Life-Space Assessment were collected. Logistic regression models showed that more severe pain was associated with greater odds of falls (OR=1.17, 95%CI=1.01-1.36), recurrent falls (OR=1.26, 95%CI=1.04-1.52), and MCI (OR=1.17, 95%CI=1.01-1.35), adjusting for sociodemographic and health characteristics. More pain interference was associated with greater odds of recurrent falls (OR=1.11, 95%CI=1.03-1.20). Structural equation modeling showed that LSM fully mediated the associations of pain severity and pain interference with MCI. Further longitudinal studies are needed to validate our findings.

Impact of Visual Input and Kinesiophobia on Postural Control and Quality of Life in Older Adults During One-Leg Standing Tasks

Visual conditions significantly influence fear of movement (FOM), which is a condition that impairs postural control and quality of life (QOL). This study examined how visual conditions influence sway velocity during repeated one-leg standing tasks and explored the potential relationship between postural control, FOM, and QOL in older adults with and without FOM. Thirty-seven older adults with FOM and 37 controls participated in the study. Postural sway velocity was measured across three repeated trials under visual conditions in both anteroposterior (AP) and mediolateral (ML) directions. The groups demonstrated significant interaction under visual conditions (F = 7.43, p = 0.01). In the eyes-closed condition, the FOM group exhibited faster ML sway velocity than the control group, with significant differences across all three trials. There was a significant interaction between sway direction and vision (F = 27.41, p = 0.001). In addition, the FOM demonstrated strong negative correlations with several QOL measures on social functioning (r = -0.69, p = 0.001) and role limitations due to emotional problems (r = -0.58, p = 0.001) in the FOM group. While FOM influenced sway velocity during balance tasks, visual input emerged as a key determinant of postural control. The FOM group demonstrated a heightened reliance on vision, suggesting an increased need for vision-dependent strategies to maintain balance.

Effects of Visual Input on Postural Stability and Compensatory Strategies in Adults with Chronic Low Back Pain

Chronic low back pain (LBP) impairs balance control due to deficits in sensory integration, yet limited research examines postural sway under varying visual conditions. This study assessed the effects of visual input on postural stability using the normalized stability index, sway excursions, and contralateral toe-touch durations during repeated one-leg standing tasks. Thirty-two adults with LBP and 40 control subjects performed dominant limb standing on a force plate. Outcome measures included the Oswestry disability index, visual analog scale, normalized stability index, sway excursions (anteroposterior [AP], mediolateral [ML]), and contralateral toe-touch duration. The LBP group showed a significant interaction for the normalized stability index under visual conditions (F = 4.95, p = 0.03) with reduced stability in the second trial of the eyes-open condition (t = 1.71, p = 0.04). Sway excursions increased in the AP direction during the first trial (t = -2.43, p = 0.01) and in the ML (t = -2.09, p = 0.02) and AP (t = -1.84, p = 0.03) directions during the third trial. Contralateral toe-touch duration increased in the second trial (t = -2.06, p = 0.02). Individuals with LBP exhibited balance deficits, particularly under eyes-open conditions, relying on compensatory strategies. Optimizing neuromuscular control and sensory integration may improve postural stability.

Assessing postural stability in flatfoot using a time-in-boundary method during single-leg standing

Flatfoot, a foot deformity characterized by the collapse of the arch, significantly impacts an individual's balance and stability. This study explored postural adjustments and sway excursions in individuals with and without flatfoot using the Time-in-Boundary method. This method assessed relative stability by exploring various center of pressure radius thresholds during three trials of single-leg stance. We observed significant interactions in threshold levels (F = 4.37, p = 0.04) and normalized relative stable times (F = 7.64, p = 0.01), particularly in the initial trials. Initially, the flatfoot group showed marked decreases in stable times at 10 mm, 15 mm, and 20 mm thresholds, which expanded to 25 mm and 30 mm in subsequent trials. Despite a significant decrease in stability at the 30 mm threshold in early trials, participants exhibited improved stability control as trials progressed. This enhancement likely reflects a combination of a learning effect and an increased understanding of the task requirements, underscoring the adaptability of postural control systems to the biomechanical challenges posed by flatfoot. The Time-in-Boundary method has proven to be an effective tool for clinicians to assess postural control, playing a vital role in developing customized rehabilitation strategies for individuals with flatfoot.

Implications for fall efficacy strategies on center of pressure and center of gravity sway distances in adults with chronic low back pain

BACKGROUND

Although chronic low back pain (LBP) is a complex condition often associated with altered motor control and compensatory postural adjustments, existing literature provides inconsistent reports on the underlying control mechanisms for maintaining balance.

PURPOSE

This study aimed to compare differences in sway distances between the center of pressure (COP) and the center of gravity (COG), while considering limb dominance, in adults with and without LBP.

METHODS

There were 26 subjects with LBP and 39 control subjects who performed three repeated unilateral standing tasks on a force platform. Outcome measures included the sway distances between COP and COG in the anteroposterior (AP) and mediolateral (ML) directions, as well as the results of the fall efficacy scale (FES).

RESULTS

A significant group interaction was demonstrated on limb dominance and direction for the sway distance (F = 5.46, p = 0.02). Specifically, the third trial in the ML direction while standing on the dominant limb indicated a significant difference in COP-COG sway distance (t = -2.30, p = 0.01). When FES scores were used as a covariate, a significant three-way interaction (dominance x direction x trial) was found (F = 4.06, p = 0.04).

CONCLUSION

Although no significant group interaction was observed for dominance, direction, and trial, the LBP group demonstrated an ability to leverage fall efficacy following repeated trials to reduce ML balance deficits. Clinicians should consider neuromuscular control and limb dominance when developing fall efficacy strategies for postural adaptations in adults with LBP.

A study on the effects of visual condition on postural stability in adults with and without chronic low back pain

This study was conducted to compare postural stability during repeated unilateral standing tasks between adults with and without chronic low back pain (LBP) while considering visual input. The study involved 26 participants with LBP and 39 control participants. Each participant performed three trials of standing tasks on the dominant limb using a stable platform. The Falls Efficacy Scale was utilized to assess fall-related self-efficacy and fear of falling due to potential physical frailty. The center of pressure (COP) sway excursion was analyzed at 10 mm and 20 mm thresholds for the time-in-boundary (TIB). The results indicated a significant fear of falling difference in the LBP group compared to the control group (t = 3.27, p = 0.001). The LBP group demonstrated a significant interaction between visual condition and TIB (F = 8.45, p = 0.01), particularly in the LBP group, which demonstrated a notable decrease in TIB at 10 mm (54.02 % compared to the control group's 70.40 %) and 20 mm (70.93 % compared to the control group's 85.92 %) thresholds during the second trial and at 10 mm (59.73 % compared to the control group's 73.84 %) during the third trial in the eyes open condition. Overall, visual condition demonstrated significant interactions on thresholds (F = 15.80, p = 0.001, η2p = 0.21) as well as trials  ×  thresholds (F = 4.21, p = 0.04, η2p = 0.07). These findings indicate a potential adaptation in postural control among the LBP group with visual feedback. Further research is warranted to explore group differences when considering visual conditions and sway excursion thresholds.

Normalized stability time analysis within the boundaries between adults with and without fear of falling

BACKGROUND

The unilateral stance test, measured by the center of pressure (COP), has been widely used to identify balance deficits. However, there is a critical gap in understanding the specific COP thresholds on postural stability in adults with a fear of falling (FOF).

AIMS

To investigate the normalized stability time, which was defined as the ratio of time spent within stability boundaries to the total test duration, under different visual conditions and specific thresholds between adults with and without FOF.

METHODS

Twenty-one older adults with FOF and 22 control subjects completed the unilateral limb standing test in eyes-open and eyes-closed conditions. Normalized stability times were computed based on five pre-determined COP sway range thresholds: 10 mm, 15 mm, 20 mm, 25 mm, and 30 mm.

RESULTS

Receiver operating characteristic analysis determined the diagnostic accuracy of FOF. There were significant differences in the effects of both visual conditions (F = 46.88, p = 0.001) and threshold settings (F = 119.38, p = 0.001) on stability time between groups. The FOF group significantly reduced normalized stability time at the 10 mm COP threshold under eyes-closed conditions (t = - 1.95, p = 0.03).

DISCUSSION

The findings highlight the heightened sensitivity of the 10 mm COP threshold in identifying group variances in postural stability when eyes are closed. Moreover, the FOF group displayed a marked reduction in stability duration based on visual scenarios and normalized thresholds.

CONCLUSION

The study highlights the need to account for both COP boundaries and visual conditions in adults with FOF. When assessing postural control during unilateral stances, clinicians must also give attention to non-visual cues.