The study utilized an integrated wearable balance and gait analysis device to characterize the balance and gait impairments in patients with high-altitude GJH. The study results validated our research hypothesis. Additionally, this is the inaugural investigation showcasing balance and gait in high-altitude GJH patients using wearable device.
Over the past decade, there has been a growing interest in wearable devices. Their portability and low cost offer a promising alternative to other systems based on optical motion capture or gait mats(28–30). However, there is a lack of research on the translation of such systems to high-altitude regions. To our knowledge, this is the first study to use wearable devices in high-altitude areas, evaluating balance and gait parameters in patients with high-altitude GJH. It not only has the accuracy of traditional gait analyzers, but also has the advantages of being portable, easy to operate, and not restricted by the environment. In high-altitude areas, it is difficult to perform gait analysis with large equipment due to inconvenient transportation and terrain. Therefore, Riablo™ has a great advantage. It can be used not only for clinical research, but also for scientific research in special settings.
In the gait analysis, the GJH group showed significantly lower walking speed and stride length compared to the healthy group. Compared to the healthy group, the GJH group showed a significantly lower percentage in the loading-response phase and a significantly higher percentage in the flat-foot phase during the stance phase. Additionally, the GJH group showed a significantly lower percentage in the swing phase, with no significant differences observed in other phases of the gait cycle. Our findings are consistent with a recently published study by Rombout et al(20). Patients with Joint hypermobility syndrome (JHS) had significantly lower walking speed, step length, and stride length compared to healthy. Also, Nikolajsen et all(35) demonstrated that children with GJH and healthy children exhibit similar walking patterns with no clinically relevant differences in kinematics.
Multiple factors may contribute to gait changes in GJH patients. Hypoxia at high altitudes may contribute to muscle fatigue and inadequate oxygen supply in individuals with GJH(36). Muscle fatigue and decreased strength can lead to changes in gait speed and stride length. This adjustment may be made to maintain balance and reduce the load on the lower limb muscles. Additionally, individuals with GJH may display specific gait abnormalities and experience decreased muscle strength(37), which can also influence gait speed. Researchers found that the incidences of sarcopenia in the high-altitude population over 60 years old were 17.2% in men and 36.0% in women, which were significantly higher than those in the plain population. This indicates that the impact of high-altitude environment on human body is significant(38). Reduced oxygen supply at high altitudes may result in an increase in the stance phase and a decrease in the swing phase for individuals with GJH(39). This adjustment may increase the body's support time against gravity, maintaining stability and facilitating adaptation to the high-altitude environment. These adjustments may represent compensatory mechanisms intended to counteract muscle fatigue and address decreased strength. Reduced postural stability(40), increased joint laxity(41), and muscle weakness(42) in individuals with GJH may collectively contribute to the observed increase in the stance phase and decrease in the swing phase. These adjustments may aim to reduce the load on the muscles in the lower limbs and decrease energy consumption(43).
In the balance function test, the experimental group showed a significant increase in both RMS and SWAY values compared to the healthy group under both EO and EC conditions. This observation suggests that individuals with GJH have poorer balance function compared to healthy individuals. Our findings are consistent with a recently published study by Juul-Kristensen et al(44), which reported higher postural sway in patients with GJH under both EO and EC conditions compared to healthy individuals. Additionally, Schmidt et al(45) also demonstrated the GJH group had the significantly larger center of pressure path length across sway tests. Joint proprioception diminishes in patients with GJH(7), affecting sensory input. Individuals with GJH exhibit a quadriceps activation disorder(16) and congenital weaknesses in soft tissues, such as laxity in joint capsules and ligaments(46). These weaknesses can result in joint instability and motor health disorders, further influencing balance function. At the same time, hypoxia, especially hypobaric, impairs standing balance. The mechanisms underpinning postural decrements likely involve alterations to processing and integration of sensorimotor signals within subcortical or cortical structures involving visual, vestibular and proprioceptive pathways and subsequent motor commands that direct postural adjustments(47). There are researchers who have found that approximately a half of the older adults from these high-altitude communities had poor balance ability(26). Although the subjects of this study were young people in the high-altitude areas, it seems to be consistent with the results of the study in terms of balance function.
The results of this study hold significant clinical implications for comprehending and managing patients with (GJH). Clinicians might find it suitable to contemplate interventions aimed at enhancing balance and gait. Nonetheless, the potential benefits of exercises targeting balance and gait improvement for patients with GJH need exploration in future research.
This study has limitations. Firstly, the subject selection did not consider gender differences. Additionally, patients with GJH often show proprioceptive deficits. Dynamic balancing requires heightened joint proprioception, which is particularly relevant to their balance functions. Assessments of dynamic balance function were not included in this study. Future research efforts could investigate the effects of gender-specific static and dynamic balance, as well as gait function, in high-altitude environments. Additionally, exploring the effectiveness of lower extremity muscle strength and balance training for the GJH population would be valuable.