Effects of water immersion on quasi-static standing exploring center of pressure sway and trunk acceleration: a case series after incomplete spinal cord injury

Clinical Static Balance Assessment: A Narrative Review of Traditional and IMU-Based Posturography in Older Adults and Individuals with Incomplete Spinal Cord Injury

Maintaining a stable upright posture is essential for performing activities of daily living, and impaired standing balance may impact an individual's quality of life. Therefore, accurate and sensitive methods for assessing static balance are crucial for identifying balance impairments, understanding the underlying mechanisms of the balance deficiencies, and developing targeted interventions to improve standing balance and prevent falls. This review paper first explores the methods to quantify standing balance. Then, it reviews traditional posturography and recent advancements in using wearable inertial measurement units (IMUs) to assess static balance in two populations: older adults and those with incomplete spinal cord injury (iSCI). The inclusion of these two groups is supported by their large representation among individuals with balance impairments. Also, each group exhibits distinct aspects in balance assessment due to diverse underlying causes associated with aging and neurological impairment. Given the high vulnerability of both demographics to balance impairments and falls, the significance of targeted interventions to improve standing balance and mitigate fall risk becomes apparent. Overall, this review highlights the importance of static balance assessment and the potential of emerging methods and technologies to improve our understanding of postural control in different populations.

Aquatic Therapy after Incomplete Spinal Cord Injury: Gait Initiation Analysis Using Inertial Sensors

Populations with potential damage to somatosensory, vestibular, and visual systems or poor motor control are often studied during gait initiation. Aquatic activity has shown to benefit the functional capacity of incomplete spinal cord injury (iSCI) patients. The present study aimed to evaluate gait initiation in iSCI patients using an easy-to-use protocol employing four wearable inertial sensors. Temporal and acceleration-based anticipatory postural adjustment measures were computed and compared between dry-land and water immersion conditions in 10 iSCI patients. In the aquatic condition, an increased first step duration (median value of 1.44 s vs. 0.70 s in dry-land conditions) and decreased root mean squared accelerations for the upper trunk (0.39 m/s² vs. 0.72 m/s² in dry-land conditions) and lower trunk (0.41 m/s² vs. 0.85 m/s² in dry-land conditions) were found in the medio-lateral and antero-posterior direction, respectively. The estimation of these parameters, routinely during a therapy session, can provide important information regarding different control strategies adopted in different environments.

Effects of water immersion on gait initiation: part II of a case series after incomplete spinal cord injury

Study design

Case series.

Objectives

This case series describes how the aquatic environment influences gait initiation in terms of the center of pressure (COP) excursion, impulses, trunk acceleration, and perceptions of participants with incomplete spinal cord injury (iSCI).

Setting

Tertiary Rehabilitation Hospital, Ontario, Canada.

Methods

Five individuals with iSCI (four cervical injuries/one thoracic injury, AIS D) participated in the study. Baseline clinical balance was evaluated by Berg Balance Scale and Mini-Balance Evaluation System Test. Participants initiated gait on a waterproof force plate and walked ~4 steps, in water and on land. COP trajectories during anticipatory and execution phases, impulses, and trunk acceleration parameters were investigated. Perceptions of walking in both environments were obtained using an interview.

Results

COP trajectory was prominently longer when individuals stepped forward. A decrease in velocity of COP was observed predominantly in the AP direction during stepping. Non-normalized vertical impulses decreased as the AP impulses increased, in water compared to land. Upper to lower trunk acceleration ratios showed how water resistance influenced the lower trunk acceleration. Most of participants reported that walking in water was challenging, but safer than on land.

Conclusions

Participants with higher balance function seemed to have more pronounced changes in anticipatory and execution phases' duration, length and velocity of COP. A faster anticipatory phase and a slower execution phase were observed in water than on land. Participants walked in water using a different trunk control strategy than on land and reported no fear of falling when walking in water versus land.