Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2010
Body-worn kinematic sensors have been widely proposed for use in portable, low cost, ambulatory m... more Body-worn kinematic sensors have been widely proposed for use in portable, low cost, ambulatory monitoring of gait. Such sensor based systems could avoid the need for high-cost laboratory-based methods for measurement of gait. We aimed to evaluate an adaptive gyroscope-based algorithm for automated temporal gait analysis using body-worn wireless gyroscopes. Temporal gait parameters were calculated from initial contact (IC) and terminal contact (TC) points derived from gyroscopes, contained in wireless sensors on the left and right shanks, using a newly developed adaptive algorithm. Gyroscope data from nine healthy adult subjects performing four walks at three different speeds were then compared against data acquired simultaneously using two force-plates. Results show that the mean true error between the adaptive gyroscope algorithm and force-plate was -5.5 ± 7.3 ms and 40.6 ± 19.2 ms for IC and TC points respectively; the latter representing a consistent, systematic error of this ma...
ABSTRACT Wireless sensing solutions that provide for accurate long term monitoring of walking and... more ABSTRACT Wireless sensing solutions that provide for accurate long term monitoring of walking and running stride characteristics in a real world environment would be an excellent tool for biomechanics researchers. The purpose of this study was to compare the performance of the SHIMMER wireless sensor platform and associated algorithm for the determination of heel-strike and stride times, across a range of speeds, to a marker-based motion capture system (CODA, Charnwood Dynamics, UK). Previous studies have shown that the SHIMMER sensor and associated algorithms can successfully calculate these parameters in slow to fast walking speeds, but it has not yet been applied to running. Five healthy subjects (4 males, 1 female, aged 27.3+/−2.1) were asked to walk and run at four different speeds on a treadmill: 2, 4, 8, 12 km/h. Two SHIMMERS were attached to the shank of left and right leg. Each SHIMMER contained a tri-axial gyroscope. Data was acquired from SHIMMER using the Biomobius software environment. Two CODA c×1 units were used to simultaneously acquire data from markers placed on the feet of the right and left foot. Data was acquired in CODAmotion software. Each subject was asked to perform two running trials at each speed, lasting 20 s each. HS was derived from the SHIMMER using a novel adaptive algorithm that is applied to the gyroscope’s medio-lateral angular velocity signal. Comparisons were made for individual steps, and left and right leg data were merged. The results show that SHIMMER is a valid tool for determining stride times in both walking and running. This is a very useful addition to SHIMMER’s existing capabilities, particularly in sporting applications where long-term monitoring of running gait characteristics, such as stride-to-stride variability, in a natural environment is of interest.
ABSTRACT This paper investigates the planarity and changes in club head trajectory throughout the... more ABSTRACT This paper investigates the planarity and changes in club head trajectory throughout the golf swing. Four male, highly skilled golfers were captured hitting 40 shots using an optical motion capture system. Planes were fitted to four phases of the golf swing for comparison across the 40 shots in each player. While trajectory variability was seen to increase from takeaway to the top of the backswing, it then decreased again leading up to impact. The correlation between the delivery horizontal plane angle and the other planes decreased the further back through the swing the plane was situated. This finding suggests that although changes to the club head trajectory in the early part of the swing may have an effect in delivery to the ball, this effect is stronger the further through the swing the change is made. This paper describes the use of a novel method for quantifying changes in club head trajectory through the golf swing.
Humans exhibit an innate ability to synchronize their movements to music. The field of gait rehab... more Humans exhibit an innate ability to synchronize their movements to music. The field of gait rehabilitation has sought to capitalize on this phenomenon by invoking patients to walk in time to rhythmic auditory cues with a view to improving pathological gait. However, the temporal structure of the auditory cue, and hence the temporal structure of the target behavior has not been sufficiently explored. This study reveals the plasticity of auditory-motor coupling in human walking in relation to 'complex' auditory cues. The authors demonstrate that auditory-motor coupling can be driven by different coloured auditory noise signals (e.g. white, brown), shifting the fractal temporal structure of gait dynamics towards the statistical properties of the signals used. This adaptive capability observed in whole-body movement, could potentially be harnessed for targeted neuromuscular rehabilitation in patient groups, depending on the specific treatment goal.
Gait variability in the context of a deterministic dynamical system may be quantified using nonli... more Gait variability in the context of a deterministic dynamical system may be quantified using nonlinear time series analyses that characterize the complexity of the system. Pathological gait exhibits altered gait variability. It can be either too periodic and predictable, or too random and disordered, as is the case with aging. While gait therapies often focus on restoration of linear measures such as gait speed or stride length, we propose that the goal of gait therapy should be to restore optimal gait variability, which exhibits chaotic fluctuations and is the balance between predictability and complexity. In this context, our purpose was to investigate how listening to different auditory stimuli affects gait variability. Twenty-seven young and 27 elderly subjects walked on a treadmill for 5 min while listening to white noise, a chaotic rhythm, a metronome, and with no auditory stimulus. Stride length, step width, and stride intervals were calculated for all conditions. Detrended Fluctuation Analysis was then performed on these time series. A quadratic trend analysis determined that an idealized inverted-U shape described the relationship between gait variability and the structure of the auditory stimuli for the elderly group, but not for the young group. This proof-of-concept study shows that the gait of older adults may be manipulated using auditory stimuli. Future work will investigate which structures of auditory stimuli lead to improvements in functional status in older adults.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2009
Development of a flexible wireless sensor platform for measurement of biomechanical and physiolog... more Development of a flexible wireless sensor platform for measurement of biomechanical and physiological variables related to functional movement would be a vital step towards effective ambulatory monitoring and early detection of risk factors in the ageing population. The small form factor, wirelessly enabled SHIMMER platform has been developed towards this end. This study is focused assessing the utility of the SHIMMER for use in ambulatory human gait analysis. Temporal gait parameters derived from a tri-axial gyroscope contained in the SHIMMER are compared against those acquired simultaneously using the CODA motion analysis system. Results from a healthy adult male subject show excellent agreement (ICC(2, k) > 0.85) in stride, swing and stance time for 10 walking trials and 4 run trials. The mean differences using the Bland and Altman method for stance, stride and swing times were 0.0087, 0.0044 and -0.0061 seconds respectively. These results suggest that the SHIMMER is a versati...
This study compares the performance of algorithms for body-worn sensors used with a spatiotempora... more This study compares the performance of algorithms for body-worn sensors used with a spatiotemporal gait analysis platform to the GAITRite electronic walkway. The mean error in detection time (true error) for heel strike and toe-off was 33.9 ± 10.4 ms and 3.8 ± 28.7 ms, respectively. The ICC for temporal parameters step, stride, swing and stance time was found to be greater than 0.84, indicating good agreement. Similarly, for spatial gait parameters--stride length and velocity--the ICC was found to be greater than 0.88. Results show good to excellent concurrent validity in spatiotemporal gait parameters, at three different walking speeds (best agreement observed at normal walking speed). The reported algorithms for body-worn sensors are comparable to the GAITRite electronic walkway for measurement of spatiotemporal gait parameters in healthy subjects.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2011
Falls in the elderly are a major problem worldwide, with enormous associated societal costs. Defi... more Falls in the elderly are a major problem worldwide, with enormous associated societal costs. Deficits in balance and postural control have long been associated with falls risk in elderly adults. The gold standard for quantitative assessment of human balance in a clinical setting is the force plate which is highly expensive, non-portable and requires specialized personnel to operate. The present study aims to evaluate the validity and reliability of a portable quantitative balance measurement technology compared to the forceplate. Two participants (1 male, 1 female) performed sixteen balance trials each (eight eyes open and eight eyes closed). Simultaneous data were recorded from a portable pressure sensor platform and a laboratory grade force platform. Standard centre of pressure (COP) metrics from both modalities were compared and high levels of agreement in terms of intraclass correlation coefficient (ICC), mean absolute error (MAE) and mean percentage error (MPE) were found.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2011
Falls in the elderly are a major problem worldwide with enormous associated economic and societal... more Falls in the elderly are a major problem worldwide with enormous associated economic and societal costs. Minimum ground clearance (MGC) is an important gait variable when considering trip-related falls risk. This study aimed to investigate the clinical relevance of inertial sensor derived parameters, previously shown to be related to MGC. Previous research by the authors reported a surrogate method for assessing minimum ground clearance (MGC) using shank-mounted inertial sensors in young controls. The present study tests this method on a cohort of 114 community dwelling elderly adults, with and without a history of falls, completing a 30 m continuous walk. Parameters based on the shank angular velocity signals that were shown to be associated with MGC showed significant differences (p<0.05) between fallers and non-fallers yet did not correlate strongly (r<0.7) with two standard measures of falls risk (TUG & BBS). Weak correlations were observed between the angular velocity der...
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2011
Recent advances in body-worn sensor technology have increased the scope for harnessing quantitati... more Recent advances in body-worn sensor technology have increased the scope for harnessing quantitative information from the timed-up-and-go test (TUG), well beyond simply the time taken to perform the test. Previous research has shown that the quantitative TUG method can differentiate fallers from non-fallers with greater success than the manually timed TUG or the Berg Balance Test. In order to advance this paradigm of falls risk estimation it is necessary to investigate the robustness of the quantitative TUG variables. This study investigated the inter-session and intra-session reliability of 44 quantitative TUG variables measured from the shanks and lower back of 33 study participants aged between 55-65 yrs. For intra-session reliability, 25 variables demonstrated excellent reliability (ICC&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;0.75), and 12 demonstrated &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;fair to good reliability&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; with ICCs between 0.4 and 0.75. Analysis of test-retest reliability resulted in ICC &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.75 for 18 out of 44 variables, with 20 variables showing fair to good reliability. Turn time parameters demonstrated poor reliability. We conclude that this is a reliable instrument that may be used as part of a long-term falls risk assessment, with further work required to improve certain turn parameters.
2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2012
Postural sway during quiet standing is associated with falls risk in older adults. The aim of thi... more Postural sway during quiet standing is associated with falls risk in older adults. The aim of this study was to investigate the utility of a range of accelerometer-derived parameters of centre of mass (COM) displacement in identifying older adults at risk of falling. A series of instrumented standing balance trials were performed to investigate postural control in a group of older adults, categorised as fallers or non-fallers. During each trial, participants were asked to stand as still as possible under two conditions: comfortable stance (six repetitions) and semi-tandem stance (three repetitions). A tri-axial accelerometer was secured to the lower back during the trials. Accelerometer data were twice integrated to estimate COM displacement during the trials, with numerical techniques used to reduce integration error. Anterior-posterior (AP) and medial-lateral (ML) sway range, sway length and sway velocity were examined, along with root mean squared (RMS) acceleration. All derived parameters significantly discriminated fallers from non-fallers during both comfortable and semi-tandem stance. Results indicate that these accelerometer-based estimates of COM displacement may improve the discriminative power of quiet standing falls risk assessments, with potential for use in unsupervised balance assessment.
The focus of this study was to monitor daily objective measures of standing postural control over... more The focus of this study was to monitor daily objective measures of standing postural control over an 8-week period, recorded in a person's home, in a population of healthy older adults. Establishing natural patterns of variation in the day-to-day signal, occurring in the relative absence of functional decline or disease, would enable us to determine thresholds for changes in postural control from baseline that could be considered clinically important. Eighteen community-dwelling older adults (3 M, 15 F, 72 ± 6 years) participated in a home-based trial where each day they were asked to complete a technology-enabled routine consisting of a short questionnaire, as well as a quiet standing balance trial. Centre of pressure (COP) excursions were calculated over the course of each daily balance trial to generate variables such as postural sway length and mean sway frequency. The data demonstrated large differences between subjects in centre of pressure measures (coefficients of variat...
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2010
Body-worn kinematic sensors have been widely proposed for use in portable, low cost, ambulatory m... more Body-worn kinematic sensors have been widely proposed for use in portable, low cost, ambulatory monitoring of gait. Such sensor based systems could avoid the need for high-cost laboratory-based methods for measurement of gait. We aimed to evaluate an adaptive gyroscope-based algorithm for automated temporal gait analysis using body-worn wireless gyroscopes. Temporal gait parameters were calculated from initial contact (IC) and terminal contact (TC) points derived from gyroscopes, contained in wireless sensors on the left and right shanks, using a newly developed adaptive algorithm. Gyroscope data from nine healthy adult subjects performing four walks at three different speeds were then compared against data acquired simultaneously using two force-plates. Results show that the mean true error between the adaptive gyroscope algorithm and force-plate was -5.5 ± 7.3 ms and 40.6 ± 19.2 ms for IC and TC points respectively; the latter representing a consistent, systematic error of this ma...
ABSTRACT Wireless sensing solutions that provide for accurate long term monitoring of walking and... more ABSTRACT Wireless sensing solutions that provide for accurate long term monitoring of walking and running stride characteristics in a real world environment would be an excellent tool for biomechanics researchers. The purpose of this study was to compare the performance of the SHIMMER wireless sensor platform and associated algorithm for the determination of heel-strike and stride times, across a range of speeds, to a marker-based motion capture system (CODA, Charnwood Dynamics, UK). Previous studies have shown that the SHIMMER sensor and associated algorithms can successfully calculate these parameters in slow to fast walking speeds, but it has not yet been applied to running. Five healthy subjects (4 males, 1 female, aged 27.3+/−2.1) were asked to walk and run at four different speeds on a treadmill: 2, 4, 8, 12 km/h. Two SHIMMERS were attached to the shank of left and right leg. Each SHIMMER contained a tri-axial gyroscope. Data was acquired from SHIMMER using the Biomobius software environment. Two CODA c×1 units were used to simultaneously acquire data from markers placed on the feet of the right and left foot. Data was acquired in CODAmotion software. Each subject was asked to perform two running trials at each speed, lasting 20 s each. HS was derived from the SHIMMER using a novel adaptive algorithm that is applied to the gyroscope’s medio-lateral angular velocity signal. Comparisons were made for individual steps, and left and right leg data were merged. The results show that SHIMMER is a valid tool for determining stride times in both walking and running. This is a very useful addition to SHIMMER’s existing capabilities, particularly in sporting applications where long-term monitoring of running gait characteristics, such as stride-to-stride variability, in a natural environment is of interest.
ABSTRACT This paper investigates the planarity and changes in club head trajectory throughout the... more ABSTRACT This paper investigates the planarity and changes in club head trajectory throughout the golf swing. Four male, highly skilled golfers were captured hitting 40 shots using an optical motion capture system. Planes were fitted to four phases of the golf swing for comparison across the 40 shots in each player. While trajectory variability was seen to increase from takeaway to the top of the backswing, it then decreased again leading up to impact. The correlation between the delivery horizontal plane angle and the other planes decreased the further back through the swing the plane was situated. This finding suggests that although changes to the club head trajectory in the early part of the swing may have an effect in delivery to the ball, this effect is stronger the further through the swing the change is made. This paper describes the use of a novel method for quantifying changes in club head trajectory through the golf swing.
Humans exhibit an innate ability to synchronize their movements to music. The field of gait rehab... more Humans exhibit an innate ability to synchronize their movements to music. The field of gait rehabilitation has sought to capitalize on this phenomenon by invoking patients to walk in time to rhythmic auditory cues with a view to improving pathological gait. However, the temporal structure of the auditory cue, and hence the temporal structure of the target behavior has not been sufficiently explored. This study reveals the plasticity of auditory-motor coupling in human walking in relation to &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;complex&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; auditory cues. The authors demonstrate that auditory-motor coupling can be driven by different coloured auditory noise signals (e.g. white, brown), shifting the fractal temporal structure of gait dynamics towards the statistical properties of the signals used. This adaptive capability observed in whole-body movement, could potentially be harnessed for targeted neuromuscular rehabilitation in patient groups, depending on the specific treatment goal.
Gait variability in the context of a deterministic dynamical system may be quantified using nonli... more Gait variability in the context of a deterministic dynamical system may be quantified using nonlinear time series analyses that characterize the complexity of the system. Pathological gait exhibits altered gait variability. It can be either too periodic and predictable, or too random and disordered, as is the case with aging. While gait therapies often focus on restoration of linear measures such as gait speed or stride length, we propose that the goal of gait therapy should be to restore optimal gait variability, which exhibits chaotic fluctuations and is the balance between predictability and complexity. In this context, our purpose was to investigate how listening to different auditory stimuli affects gait variability. Twenty-seven young and 27 elderly subjects walked on a treadmill for 5 min while listening to white noise, a chaotic rhythm, a metronome, and with no auditory stimulus. Stride length, step width, and stride intervals were calculated for all conditions. Detrended Fluctuation Analysis was then performed on these time series. A quadratic trend analysis determined that an idealized inverted-U shape described the relationship between gait variability and the structure of the auditory stimuli for the elderly group, but not for the young group. This proof-of-concept study shows that the gait of older adults may be manipulated using auditory stimuli. Future work will investigate which structures of auditory stimuli lead to improvements in functional status in older adults.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2009
Development of a flexible wireless sensor platform for measurement of biomechanical and physiolog... more Development of a flexible wireless sensor platform for measurement of biomechanical and physiological variables related to functional movement would be a vital step towards effective ambulatory monitoring and early detection of risk factors in the ageing population. The small form factor, wirelessly enabled SHIMMER platform has been developed towards this end. This study is focused assessing the utility of the SHIMMER for use in ambulatory human gait analysis. Temporal gait parameters derived from a tri-axial gyroscope contained in the SHIMMER are compared against those acquired simultaneously using the CODA motion analysis system. Results from a healthy adult male subject show excellent agreement (ICC(2, k) > 0.85) in stride, swing and stance time for 10 walking trials and 4 run trials. The mean differences using the Bland and Altman method for stance, stride and swing times were 0.0087, 0.0044 and -0.0061 seconds respectively. These results suggest that the SHIMMER is a versati...
This study compares the performance of algorithms for body-worn sensors used with a spatiotempora... more This study compares the performance of algorithms for body-worn sensors used with a spatiotemporal gait analysis platform to the GAITRite electronic walkway. The mean error in detection time (true error) for heel strike and toe-off was 33.9 ± 10.4 ms and 3.8 ± 28.7 ms, respectively. The ICC for temporal parameters step, stride, swing and stance time was found to be greater than 0.84, indicating good agreement. Similarly, for spatial gait parameters--stride length and velocity--the ICC was found to be greater than 0.88. Results show good to excellent concurrent validity in spatiotemporal gait parameters, at three different walking speeds (best agreement observed at normal walking speed). The reported algorithms for body-worn sensors are comparable to the GAITRite electronic walkway for measurement of spatiotemporal gait parameters in healthy subjects.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2011
Falls in the elderly are a major problem worldwide, with enormous associated societal costs. Defi... more Falls in the elderly are a major problem worldwide, with enormous associated societal costs. Deficits in balance and postural control have long been associated with falls risk in elderly adults. The gold standard for quantitative assessment of human balance in a clinical setting is the force plate which is highly expensive, non-portable and requires specialized personnel to operate. The present study aims to evaluate the validity and reliability of a portable quantitative balance measurement technology compared to the forceplate. Two participants (1 male, 1 female) performed sixteen balance trials each (eight eyes open and eight eyes closed). Simultaneous data were recorded from a portable pressure sensor platform and a laboratory grade force platform. Standard centre of pressure (COP) metrics from both modalities were compared and high levels of agreement in terms of intraclass correlation coefficient (ICC), mean absolute error (MAE) and mean percentage error (MPE) were found.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2011
Falls in the elderly are a major problem worldwide with enormous associated economic and societal... more Falls in the elderly are a major problem worldwide with enormous associated economic and societal costs. Minimum ground clearance (MGC) is an important gait variable when considering trip-related falls risk. This study aimed to investigate the clinical relevance of inertial sensor derived parameters, previously shown to be related to MGC. Previous research by the authors reported a surrogate method for assessing minimum ground clearance (MGC) using shank-mounted inertial sensors in young controls. The present study tests this method on a cohort of 114 community dwelling elderly adults, with and without a history of falls, completing a 30 m continuous walk. Parameters based on the shank angular velocity signals that were shown to be associated with MGC showed significant differences (p<0.05) between fallers and non-fallers yet did not correlate strongly (r<0.7) with two standard measures of falls risk (TUG & BBS). Weak correlations were observed between the angular velocity der...
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2011
Recent advances in body-worn sensor technology have increased the scope for harnessing quantitati... more Recent advances in body-worn sensor technology have increased the scope for harnessing quantitative information from the timed-up-and-go test (TUG), well beyond simply the time taken to perform the test. Previous research has shown that the quantitative TUG method can differentiate fallers from non-fallers with greater success than the manually timed TUG or the Berg Balance Test. In order to advance this paradigm of falls risk estimation it is necessary to investigate the robustness of the quantitative TUG variables. This study investigated the inter-session and intra-session reliability of 44 quantitative TUG variables measured from the shanks and lower back of 33 study participants aged between 55-65 yrs. For intra-session reliability, 25 variables demonstrated excellent reliability (ICC&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;0.75), and 12 demonstrated &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;fair to good reliability&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; with ICCs between 0.4 and 0.75. Analysis of test-retest reliability resulted in ICC &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.75 for 18 out of 44 variables, with 20 variables showing fair to good reliability. Turn time parameters demonstrated poor reliability. We conclude that this is a reliable instrument that may be used as part of a long-term falls risk assessment, with further work required to improve certain turn parameters.
2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2012
Postural sway during quiet standing is associated with falls risk in older adults. The aim of thi... more Postural sway during quiet standing is associated with falls risk in older adults. The aim of this study was to investigate the utility of a range of accelerometer-derived parameters of centre of mass (COM) displacement in identifying older adults at risk of falling. A series of instrumented standing balance trials were performed to investigate postural control in a group of older adults, categorised as fallers or non-fallers. During each trial, participants were asked to stand as still as possible under two conditions: comfortable stance (six repetitions) and semi-tandem stance (three repetitions). A tri-axial accelerometer was secured to the lower back during the trials. Accelerometer data were twice integrated to estimate COM displacement during the trials, with numerical techniques used to reduce integration error. Anterior-posterior (AP) and medial-lateral (ML) sway range, sway length and sway velocity were examined, along with root mean squared (RMS) acceleration. All derived parameters significantly discriminated fallers from non-fallers during both comfortable and semi-tandem stance. Results indicate that these accelerometer-based estimates of COM displacement may improve the discriminative power of quiet standing falls risk assessments, with potential for use in unsupervised balance assessment.
The focus of this study was to monitor daily objective measures of standing postural control over... more The focus of this study was to monitor daily objective measures of standing postural control over an 8-week period, recorded in a person's home, in a population of healthy older adults. Establishing natural patterns of variation in the day-to-day signal, occurring in the relative absence of functional decline or disease, would enable us to determine thresholds for changes in postural control from baseline that could be considered clinically important. Eighteen community-dwelling older adults (3 M, 15 F, 72 ± 6 years) participated in a home-based trial where each day they were asked to complete a technology-enabled routine consisting of a short questionnaire, as well as a quiet standing balance trial. Centre of pressure (COP) excursions were calculated over the course of each daily balance trial to generate variables such as postural sway length and mean sway frequency. The data demonstrated large differences between subjects in centre of pressure measures (coefficients of variat...
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