Few studies exist on gait adaptation caused by knee osteoarthritis (OA), and those have only expl... more Few studies exist on gait adaptation caused by knee osteoarthritis (OA), and those have only explored adaptations of the kinematics and kinetics of the knee joint itself. We characterize ankle, knee, hip, and low back mechanical energy expenditures (MEE) and compensations (MEC) during gait in patients with knee OA. Thirteen elderly patients with unilateral knee OA and 10 matched healthy elderly controls were studied during preferred and paced speed gait. Gait speed, step length, and lower extremity and low back joint MEE and MEC were compared between groups. Patients with knee OA had lower, but not significantly different, walking speed and step length compared to the controls, and had significantly different joint kinetic profiles. Patients had reduced ankle power at terminal stance, lacked a second positive peak in knee power, and had increased power absorption at the hip. Abnormal knee kinematics were exaggerated when walking at a paced speed, but hip kinetics normalized among pa...
It is unknown how vestibular dysfunction and age differentially affect balance control during fun... more It is unknown how vestibular dysfunction and age differentially affect balance control during functional activities. The objective of this study was to gain insight into the effects of age and vestibulopathy on head control when rising from a chair. Head relative to trunk (head-on-trunk) sagittal plane angular and linear control strategies were studied in patients with bilateral vestibular hypofunction (BVH) and in healthy subjects aged 30-80 years. A two-way analysis of variance was used to compare head-on-trunk kinematics by age (young vs elderly) and diagnosis (healthy vs BVH) at the time of liftoff from the seat. Angular control strategies differed with age but not diagnosis: young (healthy and BVH) subjects stabilized head rotations in space while elderly (healthy and BVH) subjects stabilized head rotations on the trunk. In contrast, linear control strategies differed by diagnosis but not age: BVH subjects (young and old) allowed a greater rate of head-on-trunk translation while healthy subjects (young and old) inhibited such translations. Young BVH subjects stabilized head-in-space rotations (as did young healthy subjects) without a functioning vestibular system, suggesting cervicocollic reflex and/or other sensory compensation for vestibular loss. Elderly BVH subjects stabilized head rotation with respect to the trunk, as did healthy elders, but did not stabilize head-on-trunk translations, suggesting a reliance on passive mechanical responses of the neck to sense head movements. We conclude that compensation strategies used by patients with vestibulopathy are age-dependent and appear to be more tractable in the younger BVH patient.
Motor and cognitive impairments are common among older adults and often co-exist, increasing thei... more Motor and cognitive impairments are common among older adults and often co-exist, increasing their risk of dementia, falls, and fractures. Gait performance is an accepted indicator of global health and it has been proposed as a valid motor marker to detect older adults at risk of developing mobility and cognitive declines including future falls and incident dementia. Our goal was to provide a gait assessment protocol to be used for clinical and research purposes. Based on a consensus that identified common evaluations to assess motor-cognitive interactions in community-dwelling older individuals, a protocol on how to evaluate gait in older adults for the Canadian Consortium on Neurodegeneration in Aging (CCNA) was developed. The CCNA gait assessment includes preferred and fast pace gait, and dual-task gait that comprises walking while performing three cognitively demanding tasks: counting backwards by ones, counting backwards by sevens, and naming animals. This gait protocol can be ...
To evaluate a new portable toolkit for quantifying upper and lower extremity muscle tone in patie... more To evaluate a new portable toolkit for quantifying upper and lower extremity muscle tone in patients with upper motor neuron syndrome (UMNS). Design: Cross-sectional, multi-site, observational trial to test and validate a new technology. Setting: Neurorehabilitation clinics at tertiary care hospitals. Participants: Four cohorts UMNS patient, >6mo post acquired brain injury, spinal cord injury, multiple sclerosis and cerebral palsy, and a sample of healthy age-matched adult controls. Measures: Strength: grip, elbow flexor and extensor, and knee extensor; Range of Motion (ROM): Passive ROM (contracture) and passive-active ROM (paresis); Objective spasticity: Stretch-reflex test for elbow, and pendulum test for knee; Subjective spasticity: Modified Ashworth Scale scores for elbow and knee flexors and extensors. Results: Measures were acquired for 103 patients from three rehabilitation clinics. Results for patient cohorts were consistent with the literature. ...
... the suggested mandate would be cost effective, practical, and would reduce barriers to helmet... more ... the suggested mandate would be cost effective, practical, and would reduce barriers to helmet ... The investigators suggested that to increase helmet use, issues of stylishness, comfort, and social ... of wearing helmets need to be addressed, and more widespread adoption of bike ...
We investigated high curvature analysis (HCA) and integrated absolute jerk (IAJ) for differrentia... more We investigated high curvature analysis (HCA) and integrated absolute jerk (IAJ) for differrentiating healthy and cerebellopathy (CB) patients performing pointing tasks. Seventeen CB patients and seventeen healthy controls were required to move a pointer at their preferred pace between two 50.8 cm laterally spaced targets while standing with theirarm extended in front of their body. HCA was used to quantify the frequency of sharp turns in the horizontal-plane (anterior-posterior and medio-lateral) velocity trajectory of the hand-held pointer. IAJ was assesssed by integration of absolute jerk (second time derivative of velocity) time histories in the anterior-posterior and medio-lateral directions. HCA scores and IAJ scores were then compared between CB patients and healthy controls; for both analyses, higher scores indicateless smooth movements. We hypothesized that CB patients would have less smooth movement trajectories than healthy controls due to upper extremity ataxia asssociated with cerebellar disease and degeneration. We found that CB patients had higher HCA scores than healthy controls (P = 0.014). Although CB patients had higher IAJ scores in both anterior-posterior (P = 0.060)and medio-lateral (P = 0.231) directions compared to the healthy controls, the differences were not significant. The difference in sensitivity between the HCA andthe IAJ analysis might be explained by primitive neural activation commands, ubiquitous though only evident with some cerebellar dysfunctions, which produce submovements which are themselves minimal jerk curves. We conclude that HCA may be a useful tool for quantifying upper extremity ataxia in CB patients performing a repeated pointing task.
American Journal of Physical Medicine Rehabilitation Association of Academic Physiatrists, Feb 1, 2007
To determine whether high-intensity functional training (FT) or strength training (ST) better ena... more To determine whether high-intensity functional training (FT) or strength training (ST) better enables impairment, disability, and functional gains among disabled community-dwelling elders. Randomized, blinded, prospective clinical trial in a large, tertiary care outpatient rehabilitation department. Fifteen elders (62-85 yrs old) referred for physical therapy with one or more impairments, including lower-limb arthritis, participated in 6 wks of FT (weekly outpatient and three to five times per week of home practice in rapid and correct execution of locomotor activities of daily living, including gait, stepping, and sit to stand) or progressive resistive ST using elastic bands with intensity, therapist contact, and home practice similar to those of FT. Both groups significantly improved their combined lower-extremity strength (hip abduction, ankle dorsiflexion, knee flexion, ankle plantarflexion, and knee extension) (P = 0.003), but no statistical difference between the ST and FT group gains (P = 0.203) was found. Subjects in both interventions improved their gait speed, but the FT group improved more than the ST group (P = 0.001). During chair rise, the FT group improved their maximum knee torque more than the ST group (P = 0.033), indicating that they employed a more controlled and efficient movement strategy. These data suggest that an intensive FT intervention results in strength improvements of comparable magnitude as those attained from ST and that FT also confers greater improvements in dynamic balance control and coordination while performing daily life tasks.
Techniques for assessing cartilage thickness from planar magnetic resonance (MR) images have trad... more Techniques for assessing cartilage thickness from planar magnetic resonance (MR) images have traditionally accounted for surface curvature only in the image plane. Many joints, such as the knee and hip, have significant curvature normal (transverse) to the image plane which results in overestimation of in-plane cartilage thickness measurements. We developed a generalized computing method for calculating spatial thickness distribution of joint cartilage from co-planar MR images which accounts for transverse surface curvature. We applied the technique using fat-suppressed SPGR (spoiled gradient recalled in the steady-state) MR images of two human acetabulae and compared the results with a previously validated spherical model of the acetabulum which also accounts for transverse curvature of the cartilage surface. The agreement between the generalized model and validated spherical model was very good for both acetabular specimens (correlation: r = 0.998, p < 0.001; differences: p > 0.63). We conclude that the generalized method is acceptable for computing spatial cartilage thickness distribution of joints with complex geometries, such as the knee.
Few studies exist on gait adaptation caused by knee osteoarthritis (OA), and those have only expl... more Few studies exist on gait adaptation caused by knee osteoarthritis (OA), and those have only explored adaptations of the kinematics and kinetics of the knee joint itself. We characterize ankle, knee, hip, and low back mechanical energy expenditures (MEE) and compensations (MEC) during gait in patients with knee OA. Thirteen elderly patients with unilateral knee OA and 10 matched healthy elderly controls were studied during preferred and paced speed gait. Gait speed, step length, and lower extremity and low back joint MEE and MEC were compared between groups. Patients with knee OA had lower, but not significantly different, walking speed and step length compared to the controls, and had significantly different joint kinetic profiles. Patients had reduced ankle power at terminal stance, lacked a second positive peak in knee power, and had increased power absorption at the hip. Abnormal knee kinematics were exaggerated when walking at a paced speed, but hip kinetics normalized among pa...
It is unknown how vestibular dysfunction and age differentially affect balance control during fun... more It is unknown how vestibular dysfunction and age differentially affect balance control during functional activities. The objective of this study was to gain insight into the effects of age and vestibulopathy on head control when rising from a chair. Head relative to trunk (head-on-trunk) sagittal plane angular and linear control strategies were studied in patients with bilateral vestibular hypofunction (BVH) and in healthy subjects aged 30-80 years. A two-way analysis of variance was used to compare head-on-trunk kinematics by age (young vs elderly) and diagnosis (healthy vs BVH) at the time of liftoff from the seat. Angular control strategies differed with age but not diagnosis: young (healthy and BVH) subjects stabilized head rotations in space while elderly (healthy and BVH) subjects stabilized head rotations on the trunk. In contrast, linear control strategies differed by diagnosis but not age: BVH subjects (young and old) allowed a greater rate of head-on-trunk translation while healthy subjects (young and old) inhibited such translations. Young BVH subjects stabilized head-in-space rotations (as did young healthy subjects) without a functioning vestibular system, suggesting cervicocollic reflex and/or other sensory compensation for vestibular loss. Elderly BVH subjects stabilized head rotation with respect to the trunk, as did healthy elders, but did not stabilize head-on-trunk translations, suggesting a reliance on passive mechanical responses of the neck to sense head movements. We conclude that compensation strategies used by patients with vestibulopathy are age-dependent and appear to be more tractable in the younger BVH patient.
Motor and cognitive impairments are common among older adults and often co-exist, increasing thei... more Motor and cognitive impairments are common among older adults and often co-exist, increasing their risk of dementia, falls, and fractures. Gait performance is an accepted indicator of global health and it has been proposed as a valid motor marker to detect older adults at risk of developing mobility and cognitive declines including future falls and incident dementia. Our goal was to provide a gait assessment protocol to be used for clinical and research purposes. Based on a consensus that identified common evaluations to assess motor-cognitive interactions in community-dwelling older individuals, a protocol on how to evaluate gait in older adults for the Canadian Consortium on Neurodegeneration in Aging (CCNA) was developed. The CCNA gait assessment includes preferred and fast pace gait, and dual-task gait that comprises walking while performing three cognitively demanding tasks: counting backwards by ones, counting backwards by sevens, and naming animals. This gait protocol can be ...
To evaluate a new portable toolkit for quantifying upper and lower extremity muscle tone in patie... more To evaluate a new portable toolkit for quantifying upper and lower extremity muscle tone in patients with upper motor neuron syndrome (UMNS). Design: Cross-sectional, multi-site, observational trial to test and validate a new technology. Setting: Neurorehabilitation clinics at tertiary care hospitals. Participants: Four cohorts UMNS patient, >6mo post acquired brain injury, spinal cord injury, multiple sclerosis and cerebral palsy, and a sample of healthy age-matched adult controls. Measures: Strength: grip, elbow flexor and extensor, and knee extensor; Range of Motion (ROM): Passive ROM (contracture) and passive-active ROM (paresis); Objective spasticity: Stretch-reflex test for elbow, and pendulum test for knee; Subjective spasticity: Modified Ashworth Scale scores for elbow and knee flexors and extensors. Results: Measures were acquired for 103 patients from three rehabilitation clinics. Results for patient cohorts were consistent with the literature. ...
... the suggested mandate would be cost effective, practical, and would reduce barriers to helmet... more ... the suggested mandate would be cost effective, practical, and would reduce barriers to helmet ... The investigators suggested that to increase helmet use, issues of stylishness, comfort, and social ... of wearing helmets need to be addressed, and more widespread adoption of bike ...
We investigated high curvature analysis (HCA) and integrated absolute jerk (IAJ) for differrentia... more We investigated high curvature analysis (HCA) and integrated absolute jerk (IAJ) for differrentiating healthy and cerebellopathy (CB) patients performing pointing tasks. Seventeen CB patients and seventeen healthy controls were required to move a pointer at their preferred pace between two 50.8 cm laterally spaced targets while standing with theirarm extended in front of their body. HCA was used to quantify the frequency of sharp turns in the horizontal-plane (anterior-posterior and medio-lateral) velocity trajectory of the hand-held pointer. IAJ was assesssed by integration of absolute jerk (second time derivative of velocity) time histories in the anterior-posterior and medio-lateral directions. HCA scores and IAJ scores were then compared between CB patients and healthy controls; for both analyses, higher scores indicateless smooth movements. We hypothesized that CB patients would have less smooth movement trajectories than healthy controls due to upper extremity ataxia asssociated with cerebellar disease and degeneration. We found that CB patients had higher HCA scores than healthy controls (P = 0.014). Although CB patients had higher IAJ scores in both anterior-posterior (P = 0.060)and medio-lateral (P = 0.231) directions compared to the healthy controls, the differences were not significant. The difference in sensitivity between the HCA andthe IAJ analysis might be explained by primitive neural activation commands, ubiquitous though only evident with some cerebellar dysfunctions, which produce submovements which are themselves minimal jerk curves. We conclude that HCA may be a useful tool for quantifying upper extremity ataxia in CB patients performing a repeated pointing task.
American Journal of Physical Medicine Rehabilitation Association of Academic Physiatrists, Feb 1, 2007
To determine whether high-intensity functional training (FT) or strength training (ST) better ena... more To determine whether high-intensity functional training (FT) or strength training (ST) better enables impairment, disability, and functional gains among disabled community-dwelling elders. Randomized, blinded, prospective clinical trial in a large, tertiary care outpatient rehabilitation department. Fifteen elders (62-85 yrs old) referred for physical therapy with one or more impairments, including lower-limb arthritis, participated in 6 wks of FT (weekly outpatient and three to five times per week of home practice in rapid and correct execution of locomotor activities of daily living, including gait, stepping, and sit to stand) or progressive resistive ST using elastic bands with intensity, therapist contact, and home practice similar to those of FT. Both groups significantly improved their combined lower-extremity strength (hip abduction, ankle dorsiflexion, knee flexion, ankle plantarflexion, and knee extension) (P = 0.003), but no statistical difference between the ST and FT group gains (P = 0.203) was found. Subjects in both interventions improved their gait speed, but the FT group improved more than the ST group (P = 0.001). During chair rise, the FT group improved their maximum knee torque more than the ST group (P = 0.033), indicating that they employed a more controlled and efficient movement strategy. These data suggest that an intensive FT intervention results in strength improvements of comparable magnitude as those attained from ST and that FT also confers greater improvements in dynamic balance control and coordination while performing daily life tasks.
Techniques for assessing cartilage thickness from planar magnetic resonance (MR) images have trad... more Techniques for assessing cartilage thickness from planar magnetic resonance (MR) images have traditionally accounted for surface curvature only in the image plane. Many joints, such as the knee and hip, have significant curvature normal (transverse) to the image plane which results in overestimation of in-plane cartilage thickness measurements. We developed a generalized computing method for calculating spatial thickness distribution of joint cartilage from co-planar MR images which accounts for transverse surface curvature. We applied the technique using fat-suppressed SPGR (spoiled gradient recalled in the steady-state) MR images of two human acetabulae and compared the results with a previously validated spherical model of the acetabulum which also accounts for transverse curvature of the cartilage surface. The agreement between the generalized model and validated spherical model was very good for both acetabular specimens (correlation: r = 0.998, p < 0.001; differences: p > 0.63). We conclude that the generalized method is acceptable for computing spatial cartilage thickness distribution of joints with complex geometries, such as the knee.
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Papers by Chris McGibbon