ECSS Paris 2023: OP-MH09
INTRODUCTION: Standing at height, and subsequent changes in emotional state (e.g., fear of falling), lead to robust alterations in balance in adults [1]. However, little is known about how height-induced postural threat affects balance performance in children. Children may lack the cognitive capability necessary to inhibit the processing of threat- and fear-related stimuli [2], and as a result, may show more marked (and perhaps detrimental) changes in postural control compared to adults. This work explored the emotional and balance responses to standing at height in children and compared responses to young and older adults. METHODS: Children (age: 9.7 ± 0.8 years, n=38), young adults (age: 21.8 ± 4.0 years, n=45) and older adults (age: 73.3 ± 5.0 years, n=15) stood in bipedal stance in two conditions: on the floor and 80 cm above ground. Centre of pressure (COP) amplitude (root mean square), frequency (mean power frequency) and complexity (sample entropy) were calculated to infer postural performance and strategy. Emotional responses were quantified by assessing balance confidence, fear of falling and perceived instability. RESULTS: Young and older adults demonstrated a postural adaptation characterised by increased frequency and decreased amplitude of the COP, in conjunction with increased COP complexity (sample entropy). In contrast, children demonstrated opposite patterns of changes: they exhibited an increase in COP amplitude and decrease in both frequency and complexity when standing in a hazardous situation. CONCLUSION: Children and adults adopted different postural control strategies when standing at height. Whilst young and older adults exhibited a (potentially protective) “stiffening” response to a height-induced threat, children demonstrated a (potentially maladaptive) ineffective postural adaptation strategy. These observations expand upon existing postural threat related research in adults, providing important new insight into understanding how children respond to standing in a hazardous situation. REFERENCES: [1] Adkin & Carpenter, Front Neurol, 2018 [2] De Sonneville et al., J Clin Exp Neuropsychol, 2002
Read CV Mathew HillECSS Paris 2023: OP-MH09
INTRODUCTION: According to the Global Burden of Disease Reports, there are 172 million falls annually, resulting in short- or long-term health impairments. Older individuals are particularly affected, making falls prevention programs crucial to reduce nursing care and mortality. Perturbation-based balance training (PBT) has gained importance in training-based falls prevention efforts due to its task-specific nature. Moreover, assessing an individual’s reactive dynamic balance in response to perturbations may serve as both an highly relevant indicator of future fall risk and a target for interventions. Early research suggests that a single session of PBT may reduce the risk of falls. Therefore, it is imperative to ascertain the impact of a diagnostic protocol on subsequent falls, which is one aim of the SeFallED study [1]. METHODS: The ongoing SeFallED study follows individuals aged 60 and above, who visit the emergency department after a fall without subsequent hospital admission. Participants undergo a comprehensive geriatric assessment and gait analyses in a laboratory (four weeks after the emergency department, and 6, 12, and 24 months later). Falls are monitored via fall calendar and monthly phone calls. In the laboratory, participants are randomly stratified to either walk on a treadmill at their preferred treadmill walking speed or experience nine different perturbations while walking on the treadmill (M-Gait, Motek Medical B.V., Amsterdam, the Netherlands). Fall rates were compared between groups six months after their initial assessment for reactive dynamic balance. RESULTS: Out of 185 eligible participants, 160 (mean age 72.2 7.7; 59 males) provided complete baseline data. Thus far, 83 participants (mean age 73.0 7.7; 36 males) have been followed up for 6 months with 29% of these individuals experiencing another fall. The number of fallers did not differ between the groups (p = 0.487). Thirteen individuals (33%) in the perturbation group experienced another fall, compared to eleven individuals (26%) in the group without perturbations. CONCLUSION: Preliminary findings indicate that the protocol employed in the SeFallED study does not impact future fall risk significantly. However, further analysis and extended follow-up durations are essential to comprehensively grasp the role of diagnosing reactive dynamic balance and its implications for future fall risk. Nevertheless, these initial results contribute to ongoing discussions regarding the optimal dosage of PBT. In high-risk individuals who have recently suffered a severe fall, a single session does not appear to provide an adequate training stimulus to induce relevant improvement. References: 1. Stuckenschneider T, et al: Sentinel fall presenting to the emergency department (SeFallED) - protocol. BMC Geriatr 2022, 22(1):594.
Read CV Tim StuckenschneiderECSS Paris 2023: OP-MH09
INTRODUCTION: Eccentric (ECC) contractions generate greater force with lower metabolic cost and cardio-respiratory constraint than concentric (CON) ones. In 2004, through electroencephalography (EEG) analysis, Fang et al. highlight that ECC induce greater cortical activity during movement planning and execution than CON contractions and more specifically greater amplitude and latency movement-related cortical potentials (MRCP). Interestingly, this was observed either in sensory-motor area and others areas. These results indicate that the use of ECC contractions could be potentially highly relevant to fight against insufficient cortical activation significantly implicated in muscle weakness of older persons or COPD patients (1). However, these results were obtained in young subjects’ upper limbs, while cortico-muscle dysfunction mainly affects the lower limbs and older persons. Thus, the purpose of this study was to compare cortical activity during quadriceps CON and ECC contractions in young (20-35 years) vs. older (50-75 years) healthy participants. METHODS: 17 young and 16 older participants (62 ± 7 and 23 ± 4 years respectively) performed 40 voluntary ECC and CON quadriceps contractions against 20% of their maximal isometric force on a Biodex isokinetic ergometer. Surface EEG signals from Cz electrode (more proximal area of quadriceps motor command) and 8 others overlying sensorimotor cortical areas, were recorded. MRCPs were derived from EEG signals in order to analyze the negative peak (NP). The amplitude and latency of the NP were calculated as indicators of cortical activation related to movement execution and planning respectively. RESULTS: As main result, Cz NP amplitude was greater during ECC contractions (p < 0.05, η2p = 0.13) for both groups (p = 0,48) despite systematic lower values in older group (p < 0.05, η2p = 0.24). As secondary results, only FC5 shows significant greater amplitude and latency during ECC contractions for both age group (p < 0.05, η2p = 0.26 and 0.20). These results exhibit a higher cortical activity during ECC contractions whatever age, and a decreased cortical activity with aging. In addition, ECC contractions performed on the lower limbs are not associated with a higher activation extended to the whole cortex areas, as found in upper limb studies. CONCLUSION: Our study shows that despite an overall reduction in motor cortex activity involved in the lower limbs during aging, the higher activity during ECC contractions of the lower limbs always exists in the older group. Consequently, this raises the interest of eccentric training to induce higher cortical activity in older individuals or COPD patients to fight against the cortical component of muscle weakness. REFERENCES: (1) Alexandre et al. (2020) Specific motor cortex hypoexcitability and hypoactivation in COPD patients with peripheral muscle weakness. BMC Pulm. Med. 20, 1. https://doi.org/10.1186/s12890-019-1042-0
Read CV Marion DesachyECSS Paris 2023: OP-MH09