Harmonic ratios: A quantification of step to step symmetry

Bellanca, Jennica L.; Lowry, Kristin A.; VanSwearingen, Jessie M.; Brach, Jennifer S.; Redfern, Mark S.

doi:10.1016/j.jbiomech.2012.12.008

Cited by 132 publications

(142 citation statements)

References 21 publications

Supporting

Mentioning

142

Contrasting

Order By: Relevance

“…Others have suggested VT and AP HRs primarily reflect changes in step-to-step symmetry [18]. Changes in trunk stability have also been reported using VT HRs [31].…”

Section: Discussionmentioning

confidence: 99%

Good Lateral Harmonic Stability Combined with Adequate Gait Speed Is Required for Low Fall Risk in Older People

Brodie

Menz²,

Smith³

et al. 2014

Gerontology

View full text Add to dashboard Cite

Background: Good lateral harmonic stability in gait may be important for minimising fall risk in older people because many falls occur during walking when the base of support is narrowest in the mediolateral (ML) direction. However, the traditional ML harmonic ratio (MLHR) may be a sub-optimal measure of gait quality because of insufficient frequency resolution. Objective: The primary objective was to investigate if a new measure of lateral harmonic stability, the 8-step MLHR, could discriminate older fallers from non-fallers while taking different walking speeds into account. Methods: Repeat walks over 20 m were completed by 96 older people (mean age 80, SD 4 years); 35 participants had a history of one or more falls in the past year. The traditional MLHR and the 8-step MLHR were obtained from an accelerometer attached to the sacrum. Results: Compared to the traditional MLHR, the 8-step MLHR demonstrated similar univariate ability to identify significant differences in fall risk based on age, walking speed and physiology (p ≤ 0.05). When differences in walking speed were taken into account, we observed that participants who walked both faster than average and had above-average lateral harmonic stability (by the 8-step MLHR) were 5.3 times less likely to be fallers than all other participants (relative risk: 0.19, 95% confidence interval: 0.06-0.57). For the traditional MLHR, however, no significant differences between the fallers and non-fallers were evident. Conclusions: The findings indicate that good lateral harmonic stability interacts with adequate gait speed and, when coincident, are associated with reduced fall risk in older people. Future research could examine whether interventions focusing on enhancing both gait speed and lateral stability can reduce fall risk and whether these combined gait measures can remotely predict deteriorating health using wearable technology.

show abstract

“…Others have suggested VT and AP HRs primarily reflect changes in step-to-step symmetry [18]. Changes in trunk stability have also been reported using VT HRs [31].…”

Section: Discussionmentioning

confidence: 99%

Good Lateral Harmonic Stability Combined with Adequate Gait Speed Is Required for Low Fall Risk in Older People

Brodie

Menz²,

Smith³

et al. 2014

Gerontology

View full text Add to dashboard Cite

show abstract

“…Finally, calculating harmonic ratios is a way to assess smoothness of walking [51], [52]. Therefore we computed the harmonic ratios of low-pass filtered acceleration signals in every anatomical direction for each stride.…”

Section: Methodsmentioning

confidence: 99%

Understanding the effects of pre-processing on extracted signal features from gait accelerometry signals

Millecamps

Lowry

Brach

et al. 2015

Computers in Biology and Medicine

View full text Add to dashboard Cite

Gait accelerometry is an important approach for gait assessment. Previous contributions have adopted various pre-processing approaches for gait accelerometry signals, but none have thoroughly investigated the effects of such pre-processing operations on the obtained results. Therefore, this paper investigated the influence of pre-processing operations on signal features extracted from gait accelerometry signals. These signals were collected from 35 participants aged over 65 years-old: 14 of them were healthy controls (HC), 10 had Parkinson’s disease (PD) and 11 had peripheral neuropathy (PN). The participants walked on a treadmill at preferred speed. Signal features in time, frequency and time-frequency domains were computed for both raw and pre-processed signals. The pre-processing stage consisted of applying tilt correction and de-noising operations to acquired signals. We first examined the effects of these operations separately, followed by the investigation of their joint effects. Several important observations were made based on the obtained results. First, the denoising operation alone had almost no effects in comparison to the trends observed in the raw data. Second, the tilt correction affected the reported results to a certain degree, which could lead to a better discrimination between groups. Third, the combination of the two pre-processing operations yielded similar trends as the tilt correction alone. These results indicated that while gait accelerometry is a valuable approach for the gait assessment, one has to carefully adopt any pre-processing steps as they alter the observed findings.

show abstract

“…For example, harmonic ratio (HR) calculated for each stride has been examined for gait symmetry and smoothness of walking, with a perfect gait symmetry returning even harmonics in two planes of movement and odd in the third [64]. Recent work proposed standardised HR guidelines aimed to improve its mathematical definition and evaluation to enhance its use as a discriminative power between different cohorts [65].…”

Section: Micro Gaitmentioning

confidence: 99%

Wearables for independent living in older adults: Gait and falls

Godfrey

2017

Maturitas

View full text Add to dashboard Cite

Solutions are needed to satisfy care demands of older adults to live independently. Wearable technology (wearables) are one approach to offer a viable means for ubiquitous, sustainable and scalable monitoring in habitual free-living environments. Gait has been presented as a relevant (bio) marker in ageing and pathological studies, with objective assessment achievable by inertial-based wearables. Commercial wearables have struggled to provide accurate analytics and have been limited by non-clinically oriented gait outcomes. Moreover, some research grade wearables also fail to provide transparent functionality due to limitations in proprietary software. Innovation within this field is often sporadic with large heterogeneity of wearable types and algorithms for gait outcomes leading to a lack of pragmatic use. This review provides a summary of recent wearable gait assessment literature, focusing on the need for an algorithm fusion approach to measurement cumulating in the ability to better detect and classify falls. A brief presentation of wearables in one pathological group is presented, identifying appropriate work for researchers in other cohorts to utilise. Opportunities for how this domain needs to progress are also summarised. Highlights• Wearables can meet older adults' needs for independent living.• Gait assessment is a (bio)marker within ageing and different pathologies.• Measuring gait with wearables has been innovative but fraught with inconsistencies.

show abstract

Harmonic ratios: A quantification of step to step symmetry

Cited by 132 publications

References 21 publications

Good Lateral Harmonic Stability Combined with Adequate Gait Speed Is Required for Low Fall Risk in Older People

Good Lateral Harmonic Stability Combined with Adequate Gait Speed Is Required for Low Fall Risk in Older People

Understanding the effects of pre-processing on extracted signal features from gait accelerometry signals

Wearables for independent living in older adults: Gait and falls

Contact Info

Product

Resources

About