Τετάρτη 1 Φεβρουαρίου 2017

Automatic Cochlear Duct Length Estimation for Selection of Cochlear Implant Electrode Arrays.

Hypothesis: Cochlear duct length (CDL) can be automatically measured for custom selection of cochlear implant (CI) electrode arrays. Background: CI electrode array selection can be influenced by measuring the CDL, which is estimated based on the length of the line that connects the round window and the lateral wall of the cochlea when passing through the modiolus. CDL measurement remains time consuming and inter-observer variability has not been studied. Methods: We evaluate an automatic approach to directly measure the two-turn (2T) CDL using existing algorithms for localizing cochlear anatomy in computed tomography (CT). Pre-op CT images of 309 ears were evaluated. Two fellowship-trained neurotologists manually and independently measured CDL. Inter-observer variability between measurements across expert and automatic observers is assessed. Inter-observer differences for choice of electrode type are also investigated. Results: Manual measurement of CDL by experts tends to underestimate cochlea size and has high inter-observer variability, with mean absolute differences between expert CDL estimations of 1.15 mm. Our results show that this can lead to a large number of cochleae for which a different electrode array type would be selected by different observers, depending on the specific threshold value of CDL used to decide between array type. Conclusion: Choosing the best CI electrode array is an important task for optimizing hearing outcomes. Manual cochleae length measurements are user-dependent, and errors impact upon the CI electrode array choice for certain patients. Measuring cochlea length automatically is less time consuming and generates more repeatable results. Our automatic approach could make use of CDL for patient-customized treatment more clinically adoptable. Copyright (C) 2017 by Otology & Neurotology, Inc. Image copyright (C) 2010 Wolters Kluwer Health/Anatomical Chart Company

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Auditory brainstem response latency in forward masking, a marker of sensory deficits in listeners with normal hearing thresholds

S03785955.gif

Publication date: Available online 1 February 2017
Source:Hearing Research
Author(s): Golbarg Mehraei, Andreu Paredes Gallardo, Barbara G. Shinn-Cunningham, Torsten Dau
In rodent models, acoustic exposure too modest to elevate hearing thresholds can nonetheless cause auditory nerve fiber deafferentation, interfering with the coding of supra-threshold sound. Low-spontaneous rate nerve fibers, important for encoding acoustic information at supra-threshold levels and in noise, are more susceptible to degeneration than high-spontaneous rate fibers. The change in auditory brainstem response (ABR) wave-V latency with noise level has been shown to be associated with auditory nerve deafferentation. Here, we measured ABR in a forward masking paradigm and evaluated wave-V latency changes with increasing masker-to-probe intervals. In the same listeners, behavioral forward masking detection thresholds were measured. We hypothesized that 1) auditory nerve fiber deafferentation increases forward masking thresholds and increases wave-V latency and 2) a preferential loss of low-SR fibers results in a faster recovery of wave-V latency as the slow contribution of these fibers is reduced. Results showed that in young audiometrically normal listeners, a larger change in wave-V latency with increasing masker-to-probe interval was related to a greater effect of a preceding masker behaviorally. Further, the amount of wave-V latency change with masker-to-probe interval was positively correlated with the rate of change in forward masking detection thresholds. Although we cannot rule out central contributions, these findings are consistent with the hypothesis that auditory nerve fiber deafferentation occurs in humans and may predict how well individuals can hear in noisy environments.



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Auditory brainstem response latency in forward masking, a marker of sensory deficits in listeners with normal hearing thresholds

S03785955.gif

Publication date: Available online 1 February 2017
Source:Hearing Research
Author(s): Golbarg Mehraei, Andreu Paredes Gallardo, Barbara G. Shinn-Cunningham, Torsten Dau
In rodent models, acoustic exposure too modest to elevate hearing thresholds can nonetheless cause auditory nerve fiber deafferentation, interfering with the coding of supra-threshold sound. Low-spontaneous rate nerve fibers, important for encoding acoustic information at supra-threshold levels and in noise, are more susceptible to degeneration than high-spontaneous rate fibers. The change in auditory brainstem response (ABR) wave-V latency with noise level has been shown to be associated with auditory nerve deafferentation. Here, we measured ABR in a forward masking paradigm and evaluated wave-V latency changes with increasing masker-to-probe intervals. In the same listeners, behavioral forward masking detection thresholds were measured. We hypothesized that 1) auditory nerve fiber deafferentation increases forward masking thresholds and increases wave-V latency and 2) a preferential loss of low-SR fibers results in a faster recovery of wave-V latency as the slow contribution of these fibers is reduced. Results showed that in young audiometrically normal listeners, a larger change in wave-V latency with increasing masker-to-probe interval was related to a greater effect of a preceding masker behaviorally. Further, the amount of wave-V latency change with masker-to-probe interval was positively correlated with the rate of change in forward masking detection thresholds. Although we cannot rule out central contributions, these findings are consistent with the hypothesis that auditory nerve fiber deafferentation occurs in humans and may predict how well individuals can hear in noisy environments.



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Auditory brainstem response latency in forward masking, a marker of sensory deficits in listeners with normal hearing thresholds

S03785955.gif

Publication date: Available online 1 February 2017
Source:Hearing Research
Author(s): Golbarg Mehraei, Andreu Paredes Gallardo, Barbara G. Shinn-Cunningham, Torsten Dau
In rodent models, acoustic exposure too modest to elevate hearing thresholds can nonetheless cause auditory nerve fiber deafferentation, interfering with the coding of supra-threshold sound. Low-spontaneous rate nerve fibers, important for encoding acoustic information at supra-threshold levels and in noise, are more susceptible to degeneration than high-spontaneous rate fibers. The change in auditory brainstem response (ABR) wave-V latency with noise level has been shown to be associated with auditory nerve deafferentation. Here, we measured ABR in a forward masking paradigm and evaluated wave-V latency changes with increasing masker-to-probe intervals. In the same listeners, behavioral forward masking detection thresholds were measured. We hypothesized that 1) auditory nerve fiber deafferentation increases forward masking thresholds and increases wave-V latency and 2) a preferential loss of low-SR fibers results in a faster recovery of wave-V latency as the slow contribution of these fibers is reduced. Results showed that in young audiometrically normal listeners, a larger change in wave-V latency with increasing masker-to-probe interval was related to a greater effect of a preceding masker behaviorally. Further, the amount of wave-V latency change with masker-to-probe interval was positively correlated with the rate of change in forward masking detection thresholds. Although we cannot rule out central contributions, these findings are consistent with the hypothesis that auditory nerve fiber deafferentation occurs in humans and may predict how well individuals can hear in noisy environments.



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Investing in Autonomy Through Student Leadership

Autonomy, professional recognition, and public recognition are all goals of the audiology profession and have been for some time now. Great strides have been made due to the hard work and dedication of many Audiologists through the years, and each one has shared the same advice; pass it on, do your share, and move it forward. Professional advocacy is something we all have a responsibility for, whether one acknowledges it or not.



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Auditory brainstem response latency in forward masking, a marker of sensory deficits in listeners with normal hearing thresholds

Publication date: Available online 1 February 2017
Source:Hearing Research
Author(s): Golbarg Mehraei, Andreu Paredes Gallardo, Barbara G. Shinn-Cunningham, Torsten Dau
In rodent models, acoustic exposure too modest to elevate hearing thresholds can nonetheless cause auditory nerve fiber deafferentation, interfering with the coding of supra-threshold sound. Low-spontaneous rate nerve fibers, important for encoding acoustic information at supra-threshold levels and in noise, are more susceptible to degeneration than high-spontaneous rate fibers. The change in auditory brainstem response (ABR) wave-V latency with noise level has been shown to be associated with auditory nerve deafferentation. Here, we measured ABR in a forward masking paradigm and evaluated wave-V latency changes with increasing masker-to-probe intervals. In the same listeners, behavioral forward masking detection thresholds were measured. We hypothesized that 1) auditory nerve fiber deafferentation increases forward masking thresholds and increases wave-V latency and 2) a preferential loss of low-SR fibers results in a faster recovery of wave-V latency as the slow contribution of these fibers is reduced. Results showed that in young audiometrically normal listeners, a larger change in wave-V latency with increasing masker-to-probe interval was related to a greater effect of a preceding masker behaviorally. Further, the amount of wave-V latency change with masker-to-probe interval was positively correlated with the rate of change in forward masking detection thresholds. Although we cannot rule out central contributions, these findings are consistent with the hypothesis that auditory nerve fiber deafferentation occurs in humans and may predict how well individuals can hear in noisy environments.



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Auditory brainstem response latency in forward masking, a marker of sensory deficits in listeners with normal hearing thresholds

Publication date: Available online 1 February 2017
Source:Hearing Research
Author(s): Golbarg Mehraei, Andreu Paredes Gallardo, Barbara G. Shinn-Cunningham, Torsten Dau
In rodent models, acoustic exposure too modest to elevate hearing thresholds can nonetheless cause auditory nerve fiber deafferentation, interfering with the coding of supra-threshold sound. Low-spontaneous rate nerve fibers, important for encoding acoustic information at supra-threshold levels and in noise, are more susceptible to degeneration than high-spontaneous rate fibers. The change in auditory brainstem response (ABR) wave-V latency with noise level has been shown to be associated with auditory nerve deafferentation. Here, we measured ABR in a forward masking paradigm and evaluated wave-V latency changes with increasing masker-to-probe intervals. In the same listeners, behavioral forward masking detection thresholds were measured. We hypothesized that 1) auditory nerve fiber deafferentation increases forward masking thresholds and increases wave-V latency and 2) a preferential loss of low-SR fibers results in a faster recovery of wave-V latency as the slow contribution of these fibers is reduced. Results showed that in young audiometrically normal listeners, a larger change in wave-V latency with increasing masker-to-probe interval was related to a greater effect of a preceding masker behaviorally. Further, the amount of wave-V latency change with masker-to-probe interval was positively correlated with the rate of change in forward masking detection thresholds. Although we cannot rule out central contributions, these findings are consistent with the hypothesis that auditory nerve fiber deafferentation occurs in humans and may predict how well individuals can hear in noisy environments.



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The VHI-10 and VHI Item Reduction Translations—Are we all Speaking the Same Language?

Publication date: Available online 31 January 2017
Source:Journal of Voice
Author(s): Mark R. Gilbert, Jackie L. Gartner-Schmidt, Clark A. Rosen
ObjectivesThe Vocal Handicap Index-10 (VHI-10) was designed as an item reduction of the original VHI to provide a quick, reliable, and quantifiable measure of patients' own vocal handicap perception. Many translations of the VHI-10 have been produced, but methodologies of translation vary between articles and do not always mirror that of the English VHI-10. This discrepancy leads to confusion about normative values and the applicability of published data in non–English-speaking cultures. This article examines the various item reductions of the VHI-10 from the VHI and the differing methodologies of translation of the VHI-10.Study DesignThis is an invited review article.MethodsPublished item reductions and translations of the VHI-10 were reviewed. Normative values for each translation, where available, were calculated. The World Health Organization recommendations for the translation of instruments are reviewed.Results/ConclusionsThere are substantial differences between the original VHI-10 (created and published in American English) and many of the translations of the VHI-10 and other proposed item reductions, both in the actual questions used and the order of the questions. We have to conclude that for a number of the non-English VHI-10/VHI reductions, the instruments are not equivalent, meaning the results from different languages are not comparable. Our recommendation for future patient-reported instrument translations is to translate and validate the instrument according to the World Health Organization protocol while maintaining item consistency and order, allowing studies to be better focused and decrease unnecessary replication of well-performed studies, as well as allowing metadata to be combined from different countries and cultures.



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Sensory reweighting after loss of auditory cues in healthy adults

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Maxime Maheu, Andréanne Sharp, Simon P. Landry, François Champoux
We maintain our balance using information provided by the visual, somatosensory, and vestibular systems on the position of our body in space. Recent evidence has suggested that auditory input also plays a significant role for postural control, yet further investigations are required to better understand the contributions of audition to this process in healthy adults. To date, the process of sensory reweighting when auditory cues are disturbed during postural control has been overlooked. The aim of this study is to determine the impact of hearing protection on sensory reweighting for postural control in healthy adults. For this, we studied 14 healthy adults on a force platform using four different postural conditions either with or without attenuation of auditory cues. Our results suggest that disturbing auditory cues increases the reliance on visual cues for postural control. This is the first study to demonstrate such a sensory reweighting occurs in the event of a sudden disturbance of auditory cues in healthy adults.



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Effects of singular and dual task constraints on motor skill variability in childhood

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Simone V. Gill, Zoe Yang, Ya-Ching Hung
We examined the effects of singular versus dual task constraints involving upper and lower extremities in typically developing children in young (4–6 years old), middle (7–9 years old), and old (10–13 years old) age groups. The purposes of this study were: 1) to investigate the effects of singular upper and lower extremity and dual upper and lower extremity conditions on motor variability and 2) to examine if variability in children’s motor actions would differ according to age (i.e., young, middle, or old). Twenty-four children (M age=8.7; SD=3.7) completed three tasks: finger rotation (upper extremity singular task constraint), obstacle crossing (lower extremity singular task constraint), and box carrying while walking (upper and lower extremity dual task constraint). Compared to the old age group, the young age group displayed more variable rotation strategies during clockwise (χ2(8, N=24)=12.4, p=0.046) and counterclockwise finger rotation (χ2(8, N=24)=12.8, p=0.047). During box carrying, children in the young age group had the most motor variability in their stride length, velocity, the vertical positioning of the box, and minimum and maximum joint excursion (all ps<0.05). Crossing leg frontal plane hip angles were more variable on low versus high obstacles (all ps<0.05). Our results suggest that four- to six-year-old children may still be developing the ability to produce consistent motor actions, especially under dual-task constraints. Examining children in the context of completing tasks with a variety of constraints may be useful in assessing the development of children's motor variability.



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Foot segmental mobility during subphases of running: Comparative study between two striking patterns

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Helen Peters, Kevin Deschamps, Giovanni Arnoldo Matricali, Filip Staes
ObjectivesThe literature lacks comparative data regarding foot segmental mobility in rearfoot (RFS) and midfoot striking (MFS) patterns. The aim of the study is to quantify the foot segmental mobility during distinct subphases of stance in presence of both striking patterns.MethodsTwelve participants were instructed to run barefoot at a constant speed of 3.3m/s on a 10-m walkway, while adopting a RFS and a MFS pattern. Multi-segment foot mobility during the impact phase, the absorption phase and the generation phase was subsequently calculated and compared between both conditions.ResultsIn the impact phase of the MFS trials, a higher sagittal plane range of motion was observed between shank and calcaneus (RFS=6.2°, MFS=14.5°, p<0.0001), between calcaneus and midfoot (RFS=1.9°, MFS=5.6°, p=0.002) as well as between the calcaneus and metatarsus (RFS=2.4°, MFS=4.9°, p=0.0015). In the absorption phase of the MFS trials, a higher frontal plane range of motion (RFS=1.3°, MFS=2.1°, p=0.004) and a lower sagittal plane range of motion (RFS=6.5°, MFS=4.3°, p=0.004) was observed between the calcaneus and metatarsus.ConclusionThis study revealed that approximately 50% of the rearfoot range of motion has been observed in the midfoot when running with both striking patterns, although the highest ROM was observed in the rearfoot. This finding highlights that the rebounding effect of the human body results not only from absorption and generation within major joints of the lower limb but also from smaller joints in the foot.



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Anatomical masking of pressure footprints based on the Oxford Foot Model: validation and clinical relevance

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Claudia Giacomozzi, Julie A. Stebbins
Plantar pressure analysis is widely used in the assessment of foot function. In order to assess regional loading, a mask is applied to the footprint to sub-divide it into regions of interest (ROIs). The most common masking method is based on geometric features of the footprint (GM). Footprint masking based on anatomical landmarks of the foot has been implemented more recently, and involves the integration of a 3D motion capture system, plantar pressure measurement device, and a multi-segment foot model. However, thorough validation of anatomical masking (AM) using pathological footprints has not yet been presented. In the present study, an AM method based on the Oxford Foot Model (OFM) was compared to an equivalent GM. Pressure footprints from 20 young healthy subjects (HG) and 20 patients with clubfoot (CF) were anatomically divided into 5 ROIs using a subset of the OFM markers. The same foot regions were also identified by using a standard GM method. Comparisons of intra-subject coefficient of variation (CV) showed that the OFM-based AM was at least as reliable as the GM for all investigated pressure parameters in all foot regions. Clinical relevance of AM was investigated by comparing footprints from HG and CF groups. Contact time, maximum force, force-time integral and contact area proved to be sensitive parameters that were able to distinguish HG and CF groups, using both AM and GM methods However, the AM method revealed statistically significant differences between groups in 75% of measured variables, compared to 62% using a standard GM method, indicating that the AM method is more sensitive for revealing differences between groups.



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Observing prioritization effects on cognition and gait: The effect of increased cognitive load on cognitively healthy older adults’ dual-task performance

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Linda M. Maclean, Laura J.E. Brown, H. Khadra, Arlene J. Astell
Previous studies exploring the effects of attention-prioritization on cognitively healthy older adults’ gait and cognitive dual task (DT) performance have shown DT cost in gait outcomes but inconsistent effects on cognitive performance, which may reflect task difficulty (the cognitive load). This study aimed to identify whether changing the cognitive load during a walking and counting DT improved the challenge/sensitivity of the cognitive task to observe prioritization effects on concurrent gait and cognitive performance outcomes. Seventy-two cognitively healthy older adults (Mean=73years) walked 15m, counted backwards in 3s and 7s as single tasks (ST), and concurrently walked and counted backwards as DTs. Attention-prioritization was examined in Prioritizing Walking (PW) and Prioritizing Counting (PC) DT conditions. Dual-task performance costs (DTC) were calculated for number of correct cognitive responses (CCR) in the counting tasks, and step-time variability and velocity in the gait task. All DT conditions showed a benefit (DTB) for cognitive outcomes with trade-off cost to gait. In the Serial 3s task, the cognitive DTBs increased in PC over the PW condition (p<0.05), with a greater cost to walking velocity (p<0.05). DT effects were more pronounced in the Serial 7s with a lower cognitive DTB when PC than when PW, (p<0.05) with no trade-off increase in cost to gait outcomes (p<0.05). The findings suggest that increased cognitive load during a gait and cognitive DT produces more pronounced gait measures of attention-prioritization in cognitively healthy older adults. A cognitive load effect was also observed in the cognitive outcomes, with unexpected results.



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Alterations in over-ground walking patterns in obese and overweight adults

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Hao Meng, Daniel P. O’Connor, Beom-Chan Lee, Charles S. Layne, Stacey L. Gorniak
Obesity has been associated with negative effects on postural control, including falls. Previous studies revealed different outcomes regarding the effects of obesity on gait features, and the use of BMI may lead to bias in assessing the true effects of obesity on gait. To better understand the effects of obesity on gait, it is important to examine gait features and associated body composition measures. The purpose of this study was: (1) to assess gait features of normal weight, overweight and obese adults, and (2) to assess the relationship between body composition measures and gait features. Thirty participants were assigned to one of three groups based upon their BMI at the onset of the study: healthy weight (BMI: 18.5–24.9kg/m2), overweight (BMI: 25–29.9kg/m2), or obese (BMI: 30–40kg/m2). Participants performed straight-line over-ground walking through a 200m hallway at their natural preferred speed while wearing their own shoes. The angular displacements, range of motion (ROM), and approximate entropy of kinematic data of the bilateral hips, knees, and ankles in the sagittal plane were computed. Walking speed, step length, stride length, single leg support phase, double leg support phase, swing phase and bilateral stance phase times were extracted from the GaitRite data. Overall, body mass and BMI were associated with peak flexion and ROM in the knees as well as single support, double support, stance, and swing phases. Body fat percentage did not exhibit correlations with measured gait features. Gait variables were more highly correlated with BMI and body mass instead of percent body fat, suggesting that absolute mass is more influential on gait features rather than amount of fat tissue.



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Sensory reweighting after loss of auditory cues in healthy adults

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Maxime Maheu, Andréanne Sharp, Simon P. Landry, François Champoux
We maintain our balance using information provided by the visual, somatosensory, and vestibular systems on the position of our body in space. Recent evidence has suggested that auditory input also plays a significant role for postural control, yet further investigations are required to better understand the contributions of audition to this process in healthy adults. To date, the process of sensory reweighting when auditory cues are disturbed during postural control has been overlooked. The aim of this study is to determine the impact of hearing protection on sensory reweighting for postural control in healthy adults. For this, we studied 14 healthy adults on a force platform using four different postural conditions either with or without attenuation of auditory cues. Our results suggest that disturbing auditory cues increases the reliance on visual cues for postural control. This is the first study to demonstrate such a sensory reweighting occurs in the event of a sudden disturbance of auditory cues in healthy adults.



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Effects of singular and dual task constraints on motor skill variability in childhood

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Simone V. Gill, Zoe Yang, Ya-Ching Hung
We examined the effects of singular versus dual task constraints involving upper and lower extremities in typically developing children in young (4–6 years old), middle (7–9 years old), and old (10–13 years old) age groups. The purposes of this study were: 1) to investigate the effects of singular upper and lower extremity and dual upper and lower extremity conditions on motor variability and 2) to examine if variability in children’s motor actions would differ according to age (i.e., young, middle, or old). Twenty-four children (M age=8.7; SD=3.7) completed three tasks: finger rotation (upper extremity singular task constraint), obstacle crossing (lower extremity singular task constraint), and box carrying while walking (upper and lower extremity dual task constraint). Compared to the old age group, the young age group displayed more variable rotation strategies during clockwise (χ2(8, N=24)=12.4, p=0.046) and counterclockwise finger rotation (χ2(8, N=24)=12.8, p=0.047). During box carrying, children in the young age group had the most motor variability in their stride length, velocity, the vertical positioning of the box, and minimum and maximum joint excursion (all ps<0.05). Crossing leg frontal plane hip angles were more variable on low versus high obstacles (all ps<0.05). Our results suggest that four- to six-year-old children may still be developing the ability to produce consistent motor actions, especially under dual-task constraints. Examining children in the context of completing tasks with a variety of constraints may be useful in assessing the development of children's motor variability.



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Foot segmental mobility during subphases of running: Comparative study between two striking patterns

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Helen Peters, Kevin Deschamps, Giovanni Arnoldo Matricali, Filip Staes
ObjectivesThe literature lacks comparative data regarding foot segmental mobility in rearfoot (RFS) and midfoot striking (MFS) patterns. The aim of the study is to quantify the foot segmental mobility during distinct subphases of stance in presence of both striking patterns.MethodsTwelve participants were instructed to run barefoot at a constant speed of 3.3m/s on a 10-m walkway, while adopting a RFS and a MFS pattern. Multi-segment foot mobility during the impact phase, the absorption phase and the generation phase was subsequently calculated and compared between both conditions.ResultsIn the impact phase of the MFS trials, a higher sagittal plane range of motion was observed between shank and calcaneus (RFS=6.2°, MFS=14.5°, p<0.0001), between calcaneus and midfoot (RFS=1.9°, MFS=5.6°, p=0.002) as well as between the calcaneus and metatarsus (RFS=2.4°, MFS=4.9°, p=0.0015). In the absorption phase of the MFS trials, a higher frontal plane range of motion (RFS=1.3°, MFS=2.1°, p=0.004) and a lower sagittal plane range of motion (RFS=6.5°, MFS=4.3°, p=0.004) was observed between the calcaneus and metatarsus.ConclusionThis study revealed that approximately 50% of the rearfoot range of motion has been observed in the midfoot when running with both striking patterns, although the highest ROM was observed in the rearfoot. This finding highlights that the rebounding effect of the human body results not only from absorption and generation within major joints of the lower limb but also from smaller joints in the foot.



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Anatomical masking of pressure footprints based on the Oxford Foot Model: validation and clinical relevance

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Claudia Giacomozzi, Julie A. Stebbins
Plantar pressure analysis is widely used in the assessment of foot function. In order to assess regional loading, a mask is applied to the footprint to sub-divide it into regions of interest (ROIs). The most common masking method is based on geometric features of the footprint (GM). Footprint masking based on anatomical landmarks of the foot has been implemented more recently, and involves the integration of a 3D motion capture system, plantar pressure measurement device, and a multi-segment foot model. However, thorough validation of anatomical masking (AM) using pathological footprints has not yet been presented. In the present study, an AM method based on the Oxford Foot Model (OFM) was compared to an equivalent GM. Pressure footprints from 20 young healthy subjects (HG) and 20 patients with clubfoot (CF) were anatomically divided into 5 ROIs using a subset of the OFM markers. The same foot regions were also identified by using a standard GM method. Comparisons of intra-subject coefficient of variation (CV) showed that the OFM-based AM was at least as reliable as the GM for all investigated pressure parameters in all foot regions. Clinical relevance of AM was investigated by comparing footprints from HG and CF groups. Contact time, maximum force, force-time integral and contact area proved to be sensitive parameters that were able to distinguish HG and CF groups, using both AM and GM methods However, the AM method revealed statistically significant differences between groups in 75% of measured variables, compared to 62% using a standard GM method, indicating that the AM method is more sensitive for revealing differences between groups.



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Observing prioritization effects on cognition and gait: The effect of increased cognitive load on cognitively healthy older adults’ dual-task performance

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Linda M. Maclean, Laura J.E. Brown, H. Khadra, Arlene J. Astell
Previous studies exploring the effects of attention-prioritization on cognitively healthy older adults’ gait and cognitive dual task (DT) performance have shown DT cost in gait outcomes but inconsistent effects on cognitive performance, which may reflect task difficulty (the cognitive load). This study aimed to identify whether changing the cognitive load during a walking and counting DT improved the challenge/sensitivity of the cognitive task to observe prioritization effects on concurrent gait and cognitive performance outcomes. Seventy-two cognitively healthy older adults (Mean=73years) walked 15m, counted backwards in 3s and 7s as single tasks (ST), and concurrently walked and counted backwards as DTs. Attention-prioritization was examined in Prioritizing Walking (PW) and Prioritizing Counting (PC) DT conditions. Dual-task performance costs (DTC) were calculated for number of correct cognitive responses (CCR) in the counting tasks, and step-time variability and velocity in the gait task. All DT conditions showed a benefit (DTB) for cognitive outcomes with trade-off cost to gait. In the Serial 3s task, the cognitive DTBs increased in PC over the PW condition (p<0.05), with a greater cost to walking velocity (p<0.05). DT effects were more pronounced in the Serial 7s with a lower cognitive DTB when PC than when PW, (p<0.05) with no trade-off increase in cost to gait outcomes (p<0.05). The findings suggest that increased cognitive load during a gait and cognitive DT produces more pronounced gait measures of attention-prioritization in cognitively healthy older adults. A cognitive load effect was also observed in the cognitive outcomes, with unexpected results.



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Alterations in over-ground walking patterns in obese and overweight adults

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Hao Meng, Daniel P. O’Connor, Beom-Chan Lee, Charles S. Layne, Stacey L. Gorniak
Obesity has been associated with negative effects on postural control, including falls. Previous studies revealed different outcomes regarding the effects of obesity on gait features, and the use of BMI may lead to bias in assessing the true effects of obesity on gait. To better understand the effects of obesity on gait, it is important to examine gait features and associated body composition measures. The purpose of this study was: (1) to assess gait features of normal weight, overweight and obese adults, and (2) to assess the relationship between body composition measures and gait features. Thirty participants were assigned to one of three groups based upon their BMI at the onset of the study: healthy weight (BMI: 18.5–24.9kg/m2), overweight (BMI: 25–29.9kg/m2), or obese (BMI: 30–40kg/m2). Participants performed straight-line over-ground walking through a 200m hallway at their natural preferred speed while wearing their own shoes. The angular displacements, range of motion (ROM), and approximate entropy of kinematic data of the bilateral hips, knees, and ankles in the sagittal plane were computed. Walking speed, step length, stride length, single leg support phase, double leg support phase, swing phase and bilateral stance phase times were extracted from the GaitRite data. Overall, body mass and BMI were associated with peak flexion and ROM in the knees as well as single support, double support, stance, and swing phases. Body fat percentage did not exhibit correlations with measured gait features. Gait variables were more highly correlated with BMI and body mass instead of percent body fat, suggesting that absolute mass is more influential on gait features rather than amount of fat tissue.



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Sensory reweighting after loss of auditory cues in healthy adults

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Maxime Maheu, Andréanne Sharp, Simon P. Landry, François Champoux
We maintain our balance using information provided by the visual, somatosensory, and vestibular systems on the position of our body in space. Recent evidence has suggested that auditory input also plays a significant role for postural control, yet further investigations are required to better understand the contributions of audition to this process in healthy adults. To date, the process of sensory reweighting when auditory cues are disturbed during postural control has been overlooked. The aim of this study is to determine the impact of hearing protection on sensory reweighting for postural control in healthy adults. For this, we studied 14 healthy adults on a force platform using four different postural conditions either with or without attenuation of auditory cues. Our results suggest that disturbing auditory cues increases the reliance on visual cues for postural control. This is the first study to demonstrate such a sensory reweighting occurs in the event of a sudden disturbance of auditory cues in healthy adults.



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Effects of singular and dual task constraints on motor skill variability in childhood

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Simone V. Gill, Zoe Yang, Ya-Ching Hung
We examined the effects of singular versus dual task constraints involving upper and lower extremities in typically developing children in young (4–6 years old), middle (7–9 years old), and old (10–13 years old) age groups. The purposes of this study were: 1) to investigate the effects of singular upper and lower extremity and dual upper and lower extremity conditions on motor variability and 2) to examine if variability in children’s motor actions would differ according to age (i.e., young, middle, or old). Twenty-four children (M age=8.7; SD=3.7) completed three tasks: finger rotation (upper extremity singular task constraint), obstacle crossing (lower extremity singular task constraint), and box carrying while walking (upper and lower extremity dual task constraint). Compared to the old age group, the young age group displayed more variable rotation strategies during clockwise (χ2(8, N=24)=12.4, p=0.046) and counterclockwise finger rotation (χ2(8, N=24)=12.8, p=0.047). During box carrying, children in the young age group had the most motor variability in their stride length, velocity, the vertical positioning of the box, and minimum and maximum joint excursion (all ps<0.05). Crossing leg frontal plane hip angles were more variable on low versus high obstacles (all ps<0.05). Our results suggest that four- to six-year-old children may still be developing the ability to produce consistent motor actions, especially under dual-task constraints. Examining children in the context of completing tasks with a variety of constraints may be useful in assessing the development of children's motor variability.



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Foot segmental mobility during subphases of running: Comparative study between two striking patterns

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Helen Peters, Kevin Deschamps, Giovanni Arnoldo Matricali, Filip Staes
ObjectivesThe literature lacks comparative data regarding foot segmental mobility in rearfoot (RFS) and midfoot striking (MFS) patterns. The aim of the study is to quantify the foot segmental mobility during distinct subphases of stance in presence of both striking patterns.MethodsTwelve participants were instructed to run barefoot at a constant speed of 3.3m/s on a 10-m walkway, while adopting a RFS and a MFS pattern. Multi-segment foot mobility during the impact phase, the absorption phase and the generation phase was subsequently calculated and compared between both conditions.ResultsIn the impact phase of the MFS trials, a higher sagittal plane range of motion was observed between shank and calcaneus (RFS=6.2°, MFS=14.5°, p<0.0001), between calcaneus and midfoot (RFS=1.9°, MFS=5.6°, p=0.002) as well as between the calcaneus and metatarsus (RFS=2.4°, MFS=4.9°, p=0.0015). In the absorption phase of the MFS trials, a higher frontal plane range of motion (RFS=1.3°, MFS=2.1°, p=0.004) and a lower sagittal plane range of motion (RFS=6.5°, MFS=4.3°, p=0.004) was observed between the calcaneus and metatarsus.ConclusionThis study revealed that approximately 50% of the rearfoot range of motion has been observed in the midfoot when running with both striking patterns, although the highest ROM was observed in the rearfoot. This finding highlights that the rebounding effect of the human body results not only from absorption and generation within major joints of the lower limb but also from smaller joints in the foot.



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Anatomical masking of pressure footprints based on the Oxford Foot Model: validation and clinical relevance

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Claudia Giacomozzi, Julie A. Stebbins
Plantar pressure analysis is widely used in the assessment of foot function. In order to assess regional loading, a mask is applied to the footprint to sub-divide it into regions of interest (ROIs). The most common masking method is based on geometric features of the footprint (GM). Footprint masking based on anatomical landmarks of the foot has been implemented more recently, and involves the integration of a 3D motion capture system, plantar pressure measurement device, and a multi-segment foot model. However, thorough validation of anatomical masking (AM) using pathological footprints has not yet been presented. In the present study, an AM method based on the Oxford Foot Model (OFM) was compared to an equivalent GM. Pressure footprints from 20 young healthy subjects (HG) and 20 patients with clubfoot (CF) were anatomically divided into 5 ROIs using a subset of the OFM markers. The same foot regions were also identified by using a standard GM method. Comparisons of intra-subject coefficient of variation (CV) showed that the OFM-based AM was at least as reliable as the GM for all investigated pressure parameters in all foot regions. Clinical relevance of AM was investigated by comparing footprints from HG and CF groups. Contact time, maximum force, force-time integral and contact area proved to be sensitive parameters that were able to distinguish HG and CF groups, using both AM and GM methods However, the AM method revealed statistically significant differences between groups in 75% of measured variables, compared to 62% using a standard GM method, indicating that the AM method is more sensitive for revealing differences between groups.



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Observing prioritization effects on cognition and gait: The effect of increased cognitive load on cognitively healthy older adults’ dual-task performance

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Linda M. Maclean, Laura J.E. Brown, H. Khadra, Arlene J. Astell
Previous studies exploring the effects of attention-prioritization on cognitively healthy older adults’ gait and cognitive dual task (DT) performance have shown DT cost in gait outcomes but inconsistent effects on cognitive performance, which may reflect task difficulty (the cognitive load). This study aimed to identify whether changing the cognitive load during a walking and counting DT improved the challenge/sensitivity of the cognitive task to observe prioritization effects on concurrent gait and cognitive performance outcomes. Seventy-two cognitively healthy older adults (Mean=73years) walked 15m, counted backwards in 3s and 7s as single tasks (ST), and concurrently walked and counted backwards as DTs. Attention-prioritization was examined in Prioritizing Walking (PW) and Prioritizing Counting (PC) DT conditions. Dual-task performance costs (DTC) were calculated for number of correct cognitive responses (CCR) in the counting tasks, and step-time variability and velocity in the gait task. All DT conditions showed a benefit (DTB) for cognitive outcomes with trade-off cost to gait. In the Serial 3s task, the cognitive DTBs increased in PC over the PW condition (p<0.05), with a greater cost to walking velocity (p<0.05). DT effects were more pronounced in the Serial 7s with a lower cognitive DTB when PC than when PW, (p<0.05) with no trade-off increase in cost to gait outcomes (p<0.05). The findings suggest that increased cognitive load during a gait and cognitive DT produces more pronounced gait measures of attention-prioritization in cognitively healthy older adults. A cognitive load effect was also observed in the cognitive outcomes, with unexpected results.



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Alterations in over-ground walking patterns in obese and overweight adults

Publication date: March 2017
Source:Gait & Posture, Volume 53
Author(s): Hao Meng, Daniel P. O’Connor, Beom-Chan Lee, Charles S. Layne, Stacey L. Gorniak
Obesity has been associated with negative effects on postural control, including falls. Previous studies revealed different outcomes regarding the effects of obesity on gait features, and the use of BMI may lead to bias in assessing the true effects of obesity on gait. To better understand the effects of obesity on gait, it is important to examine gait features and associated body composition measures. The purpose of this study was: (1) to assess gait features of normal weight, overweight and obese adults, and (2) to assess the relationship between body composition measures and gait features. Thirty participants were assigned to one of three groups based upon their BMI at the onset of the study: healthy weight (BMI: 18.5–24.9kg/m2), overweight (BMI: 25–29.9kg/m2), or obese (BMI: 30–40kg/m2). Participants performed straight-line over-ground walking through a 200m hallway at their natural preferred speed while wearing their own shoes. The angular displacements, range of motion (ROM), and approximate entropy of kinematic data of the bilateral hips, knees, and ankles in the sagittal plane were computed. Walking speed, step length, stride length, single leg support phase, double leg support phase, swing phase and bilateral stance phase times were extracted from the GaitRite data. Overall, body mass and BMI were associated with peak flexion and ROM in the knees as well as single support, double support, stance, and swing phases. Body fat percentage did not exhibit correlations with measured gait features. Gait variables were more highly correlated with BMI and body mass instead of percent body fat, suggesting that absolute mass is more influential on gait features rather than amount of fat tissue.



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