Normative database of postural sway measures using inertial sensors in typically developing children and young adults

Normative values of spinal and peripheral proprioception in position sense among healthy adolescents and young adults

Establishing normative values and understanding how proprioception varies among body parts is crucial. However, the variability across individuals, especially adolescents, makes it difficult to establish norms. This prevents further investigation into classifying patients with abnormal proprioception. Therefore, the primary objective was to address the knowledge gap using three-dimensional motion analysis to capture position sense in adolescents and young adults. The secondary objective was to evaluate the relationship between position sense and age, as well as the interrelationships of position senses across various anatomical sites. Healthy participants aged 10 to 25 years were included. Six position sense tests were implemented on the trunk, neck, elbow, and knee. Data were captured using a three-dimensional motion capture system. The proprioceptive measure was the absolute repositioning error (the difference between the destinated starting position and the corresponding self-reproduced ending position) of each test. A total of 103 participants were recruited. We found that only spinal proprioception was associated with chronological age, whereas peripheral proprioception was not. Subgroup analyses revealed that subjects aged 10 to 13 years had the poorest proprioceptive performance. The normative values of proprioception of various body parts were, trunk flexion-extension test = 25° ± 12°; trunk lateral-flexion test = 23° ± 10°; trunk axial-rotation test = 26° ± 11°; left neck rotation test = 2° ± 1°; right neck rotation test = 3° ± 1°; left elbow flexion test = 5° ± 3°; right elbow flexion test = 5° ± 2°; left knee extension test = 3° ± 2°; right knee extension test = 3° ± 1°. The normative values of proprioception in position sense provided in this study may help identify individuals with proprioceptive deficits and inform targeted interventions to improve proprioception.

Measurement properties of Brief-BESTest scores from children, adolescents, and youth with visual impairments

Purpose: This study aimed to vet the measurement properties of Brief-BESTest scores in children, adolescents, and youth with visual impairment and blindness (YVI). Methods: A cross-sectional sample of YVI (N = 101) completed the Brief-BESTest, a modified version of the Y-Balance Test, the 360-degree turn test, bipedal quiet stance, and Activity-Specific Balance Confidence Scales. Thirty-seven YVI completed test-retest of the Brief-BESTest using a one-year interval. Using classical test theory, various forms of total and item-level Brief-BESTest score reliability and validity were investigated in YVI. Results: All inter-rater reliability coefficients were ≥ .80. When considering the eight items of the Brief-BESTest, 27 of the 28 possible correlations were statistically significant (p<.05). Various internal consistency and item difficulty results were strong. When taking total Brief-BESTest scores and their association with the complementary balance tasks/metrics into account, 11 of 13 associations were statistically significant (p<.05) providing strong convergent validity evidence. Being multimorbid and degree of vision significantly predicted total Brief-BESTest scores (p<.001) suggesting construct (i.e. known groups) validity. Numerous test-retest results (e.g. coefficients, limits of agreement) following the one-year interval were indicative of score stability. Conclusion: Practitioners and researchers should have confidence in, and consider adopting, the Brief-BESTest to examine multidimensional balance in YVI.

Effect of psychostimulant medications on static balance performance in adults with attention deficit hyperactivity disorder: Within-subjects repeated-measure study

OBJECTIVE

This study examined the effect of psychostimulant medications nPS) on balance and functional motor performance in adults with attention-deficit/hyperactivity disorder (ADHD).

METHODS

Participants completed two sessions (off-medication and on-medication) in a within-subjects repeated-measure study design. There was a minimum of seven days between the two sessions. During both sessions, participants stood for 30 s per condition on a force platform. The conditions were: feet-apart with 1) eyes-open and 2) eyes-closed; feet-together with 3) eyes-open and 4) eyes-closed. Participants performed three trials of timed up and go (TUG) and lateral step-up test (LSUT) during both sessions. Outcome measures were sway area (SA [cm²]), average sway velocity (SV [cm/s]), TUG average time (s), and average number of LSUT repetitions. Data were analyzed using multivariate repeated measures analysis of variance and paired t-tests for examining PS effects on balance (SA and SV) and functional motor performance (TUG and LSUT), respectively.

RESULTS

The sample included 45 adults (35 females; mean age = 28.4 ± 6.3 years). The repeated-measures MANOVA indicated that PS was associated with better SA [F(1,44) = 9.6; p = 0.003;η_p² = 0.18] but not with SV [F(1,44) = 1.0; p = 0.319;η_p² = 0.02]. PS was associated with significantly better SA with decreasing base-of-support [F(1,44) = 9.9; p = 0.003;η_p² = 0.18]. Additionally, PS use was associated with better TUG [t(1,44) = 2.65; p = 0.014;Cohen's d = 0.39] but not LSUT performances [t(1,44) = -0.68; p = 0.499;Cohen's d = -0.10].

CONCLUSIONS

PS was associated with better SA and TUG in adults with ADHD. Further studies are needed to investigate the effects of PS on balance performance using rigorous designs in this population.

IMPACT

Healthcare providers should screen for PS status and balance when treating adults with ADHD to enhance safe motor performance.

Lifespan changes in postural control

Lifespan development of postural control shows as an inverted U-shaped function with optimal performance in young adults and similar levels of underperformance in children and older adults. However, similarities in children and older adults might conceal differences in underlying control processes. We mapped out age-related differences in postural control using center-of-pressure trajectories of 299 participants ranging from 7 to 81 years old in three tasks: stable stance, compromised vision, and narrowed base of support. Summary statistics (path length, ellipse area) replicated the well-known U-shape function also showing that compromising vision and narrowing the base of support affected older adults more than children. Stabilogram diffusion analysis (SDA) allows to assess postural control performance in terms of diffusion at short (< 1 s) and longer timescales. SDA parameters showed the strongest short-term drift in older adults, especially under compromised vision or narrowed base of support conditions. However, older adults accommodated their poor short-term control by corrective adjustments as reflected in long-term diffusion under eyes closed conditions and initiating anti-persistent behavior earlier compared with children and young adults in tandem stance. We argue that these results highlight the adaptability of the postural control system and warrant a reinterpretation of previous postural control frameworks.

Incongruity of Geometric and Spectral Markers in the Assessment of Body Sway

Different measurements of body oscillations in the time or frequency domain are being employed as markers of gait and balance abnormalities. This study investigates basic relationships within and between geometric and spectral measures in a population of young adult subjects. Twenty healthy subjects stood with parallel feet on a force platform with and without a foam pad. Adaptation effects to prolonged stance were assessed by comparing the first and last of a series of eight successive trials. Centre of Foot Pressure (CoP) excursions were recorded with Eyes Closed (EC) and Open (EO) for 90s. Geometric measures (Sway Area, Path Length), standard deviation (SD) of the excursions, and spectral measure (mean power Spectrum Level and Median Frequency), along the medio-lateral (ML) and antero-posterior (AP) direction were computed. Sway Area was more strongly associated than Path Length with CoP SD and, consequently, with mean Spectrum Level for both ML and AP, and both visual and surface conditions. The squared-SD directly specified the mean power Spectrum Level of CoP excursions (ML and AP) in all conditions. Median Frequency was hardly related to Spectrum Level. Adaptation had a confounding effect, whereby equal values of Sway Area, Path Length, and Spectrum Level corresponded to different Median Frequency values. Mean Spectrum Level and SDs of the time series of CoP ML and AP excursions convey the same meaning and bear an acceptable correspondence with Sway Area values. Shifts in Median Frequency values represent important indications of neuromuscular control of stance and of the effects of vision, support conditions, and adaptation. The Romberg Quotient EC/EO for a given variable is contingent on the compliance of the base of support and adaptation, and different between Sway Area and Path Length, but similar between Sway Area and Spectrum Level (AP and ML). These measures must be taken with caution in clinical studies, and considered together in order to get a reliable indication of overall body sway, of modifications by sensory and standing condition, and of changes with ageing, medical conditions and rehabilitation treatment. However, distinct measures shed light on the discrete mechanisms and complex processes underpinning the maintenance of stance.

Quantification of the development of trunk control in healthy infants using inertial measurement units

Trunk motor control is essential for the proper functioning of the upper extremities and is an important predictor of gait capacity in children with delayed development. Early diagnosis and intervention could increase the trunk motor capabilities in later life, but current tools used to assess the level of trunk motor control are largely subjective and many lack the sensitivity to accurately monitor development and the effects of therapy. Inertial measurement units could yield an objective quantitative assessment that is inexpensive and easy-to-implement. We hypothesized that root mean square of jerk, a proxy for movement smoothness, could be used to distinguish age and thereby presumed motor development. We attached a sensor to the trunks of six young children with no known developmental deficits. Root mean square of jerk decreases with age, up to 24 months, and is correlated to a more established method, i.e., center-of-pressure velocity, as well as other standard inertial measurement unit outputs. This metric therefore shows potential as a method to differentiate trunk motor control levels.

Increased 18F-FDG Uptake in the Axillary Lymph Nodes of the Vaccinated Side Associated with COVID-19 Vaccination

A 50-year-old female patient underwent (¹⁸fluorine-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) following modified radical mastectomy for cancer of the left breast. Ten days before the PET/CT, the coronavirus disease-2019 (COVID-19) vaccine was injected intramuscularly into the right deltoid muscle. Increased (¹⁸F-FDG uptake of maximum standardized uptake value (11.0) was observed in the lymph nodes of the right axilla, which had not been observed in the previous PET/CT. The size of the oval-shaped lymph nodes was up to approximately 11×9 mm; however, it was larger than that observed on the previous PET/CT. We contemplate that the increased (¹⁸F-FDG uptake was a reactive change in the lymph nodes associated with the COVID-19 vaccine.

Wearable sensors detect impaired gait and coordination in LBSL during remote assessments

Background

Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a rare leukodystrophy with motor impairment due to biallelic mutations in DARS2, which encodes mitochondrial aspartyl tRNA synthetase. Progressive ataxia is the primary feature.

Objective

The study objective is to determine the feasibility of remotely collecting quantitative gait and balance measures in LBSL.

Methods

The study design uses wearable accelerometers and the scale for the assessment and rating of ataxia (SARA) scale to assess gait and postural sway in LBSL and control participants' homes through video conferencing.

Results

Lateral step variability (LSV), which indicates stride variability, and elevation of the step at mid‐swing are increased for LBSL patients during brief walking tests. During stance with the eyes closed, LBSL participants show rapid accelerations and decelerations of body movement covering a large sway area and path. Both the LSV and sway area during stance with the feet together and eyes closed correlate strongly with the SARA.

Conclusions

Wearable accelerometers are valid and sensitive for detecting ataxia in LBSL patients during remote assessments. The finding of large increases in the sway area during stance with the eyes closed is intriguing since dorsal column dysfunction is universally seen in LBSL. This approach can be applied to related rare diseases that feature ataxia.

Mechanography in children: pediatric references in postural control

OBJECTIVE

To establish pediatric age- and sex-specific references for measuring postural control with a mechanography plate in a single centre, prospective, normative data study.

METHODS

739 children and adolescents (396 male/343 female) aged 4 to 17 years were studied. Each participant completed the following test sequence three times: Romberg, semi-tandem, tandem, each with eyes open and closed, and a one-leg stand with eyes open, and a single two-legged jump. Normal ranges were determined based on percentile calculations using the LMS method. Results from the two-legged jump were compared to a reference population the single two-legged jump (s2LJ) assessment in 2013.

RESULTS

38 different equilibrium parameters calculated were analysed. Of all parameters Path Length, vCoFmean, Equilibrium Score and Sway Angle showed a low variation within the same age group but high dependency on age and were thus chosen for automated balance assessment.

CONCLUSION

Standard values of postural control in healthy children derived from automated balance testing using a mechanography plate were successfully acquired and a subset of parameters for automated balance assessment identified.