William H. Gage

Evaluation of gait symmetry after stroke: a comparison of current methods and recommendations for standardization.

Symmetry is a gait characteristic that is increasingly measured and reported, particularly in the stroke patient population. However, there is no accepted standard for assessing symmetry making it difficult to compare across studies and establish criteria to guide clinical decision making. This study compares the most common expressions of spatiotemporal gait symmetry to describe post-stroke gait and makes recommendations regarding the most suitable measure for standardization. The following symmetry equations were compared: symmetry ratio, symmetry index, gait asymmetry and symmetry angle using step length, swing time, stance time, double support time and an intra-limb ratio of swing: stance time. Comparisons were made within a group of 161 community-dwelling, ambulatory individuals with stroke and 81 healthy adults as a reference group. Our analysis supports the recommendations of the symmetry ratio as the equation for standardization and step length, swing time and stance time as the gait parameters to be used in the equation. Future work should focus on establishing the intra-individual variability of these measures and linking them to mechanisms of gait dysfunction.

Changes in Gait Symmetry and Velocity After Stroke: A Cross-Sectional Study From Weeks to Years After Stroke:

Background. There is little information about the quality of gait in the years following stroke. Long-term changes in mobility, using global indices of function, suggest a decline well after initial rehabilitation. However, global indices of mobility do not reveal more specific changes in walking competency or underlying gait-specific impairment. Objectives. The authors used a cross-sectional design with gait-specific measures (velocity and symmetry) to investigate whether deterioration in gait occurs over the long term poststroke. Methods. Data were abstracted from a standardized database containing clinical assessments and spatiotemporal gait analyses for 171 individuals with stroke. Velocity and 3 expressions of symmetry ratios (swing time, stance time, and step length) were calculated for each individual; they were then assigned to 1 of the 5 following groups: 0 to 3, 3 to 12, 12 to 24, 24 to 48, and >48 months poststroke. Results. Swing time, stance time, and step length symmetry demonstrated a systematic linear trend toward greater asymmetry in groups in the later stages poststroke, whereas velocity, neurological deficit, and lower-extremity (LE) motor impairment did not. Conclusions. The quality of gait, as measured by spatial and temporal symmetry, appears to worsen in later years. These results suggest a dissociation between quantitative measures of gait, such as velocity versus symmetry, and that these parameters may measure independent features. A longitudinal study is needed to confirm the presence and to interpret the clinical meaning of a long-term decline in specific parameters of poststroke gait.

A Novel Approach to Ambulatory Monitoring Investigation Into the Quantity and Control of Everyday Walking in Patients With Subacute Stroke

Background. Promoting whole body activities, such as walking, can help improve recovery after stroke. However, little information exists regarding the characteristics of daily walking in patients enrolled in rehabilitation poststroke. The objectives of this study were to: (1) examine the quantity of walking and duration of individual bouts of walking during an inpatient day, (2) compare standard laboratory symmetry measures with measures of symmetry captured throughout the day, and (3) investigate the association between quantity of walking and indices of stroke severity. Methods. The study examined ambulatory activity among 16 inpatients with subacute stroke who were bilaterally instrumented with a wireless accelerometer above the ankle for approximately 8 continuous hours. Results. On average, patients demonstrated 47.5 minutes (standard deviation [SD] = 26.6 minutes) of total walking activity and walking bout durations of 54.4 s (SD = 21.5 s). A statistically significant association was found between the number of walking bouts to total walking time (r = .76; P = .006) and laboratory gait speed (r = .51; P = .045) and between laboratory gait speed and balance impairment (r = .60; P = .013). Also, a significant increase in gait asymmetry was observed during day-long measurement compared with the standard laboratory-based assessment (P = .006). Conclusions. Rather modest amounts of daily walking were found for these ambulatory inpatients, consistent with previous reports about patients after stroke. Bouts of walking were short in duration, and the gait was more asymmetrical, compared with a standard gait assessment. Unobtrusive monitoring of daily walking exposes the characteristics and temporal qualities of poststroke ambulation.

Reducing fall risk by improving balance control: Development, evaluation and knowledge-translation of new approaches

PROBLEM Falling is a leading cause of serious injury, loss of independence, and nursing-home admission in older adults. Impaired balance control is a major contributing factor. METHODS Results from our balance-control studies have been applied in the development of new and improved interventions and assessment tools. Initiatives to facilitate knowledge-translation of this work include setting up a new network of balance clinics, a research-user network and a research-user advisory board. RESULTS Our findings support the efficacy of the developed balance-training methods, balance-enhancing footwear, neuro-prosthesis, walker design, handrail-cueing system, and handrail-design recommendations in improving specific aspects of balance control. IMPACT ON KNOWLEDGE USERS: A new balance-assessment tool has been implemented in the first new balance clinic, a new balance-enhancing insole is available through pharmacies and other commercial outlets, and handrail design recommendations have been incorporated into 10 Canadian and American building codes. Work in progress is expected to have further impact.

Postural control is altered in patients with ankylosing spondylitis.

BACKGROUND Ankylosing spondylitis is a chronic inflammatory disorder that can lead to increased axial and peripheral joint stiffness, impairing joint mobility. Impaired axial mobility due to vertebral ankylosis may result in changes in standing postural control. Little research has addressed changes in standing postural control in the ankylosing spondylitis population, nor how these issues might affect clinical understanding and treatment. METHODS Sixteen ankylosing spondylitis patients, and 17 healthy controls participated. Each individual completed two 120-second quiet standing trials with eyes open and eyes closed, while standing upon two force platforms. Net center of pressure displacement and mean power frequency in the frontal and sagittal planes were calculated. A Spearmans rank correlation analysis was performed between net center of pressure measures and several clinical measures of disease activity. FINDINGS Frontal plane net center of pressure displacement and frequency content, and sagittal plane net center of pressure displacement were significantly greater within the ankylosing spondylitis patient group. Ankylosing spondylitis patients demonstrated a significant increase in frontal plane net center of pressure displacement in the eyes-closed condition. Net center of pressure displacement and frequency were significantly correlated to the Bath Ankylosing Spondylitis Functional Index, and individual components of the Bath Ankylosing Spondylitis Metrology Index. INTERPRETATION Quiet standing postural control was altered particularly so in the frontal plane in patients with ankylosing spondylitis, which may be associated with increased fall risk. Posturographic measures of postural control may serve as valuable clinical tools for the monitoring of disease progression and disease status in ankylosing spondylitis.

Cardiovascular Responses Associated with Daily Walking in Subacute Stroke

Despite the importance of regaining independent ambulation after stroke, the amount of daily walking completed during in-patient rehabilitation is low. The purpose of this study is to determine if (1) walking-related heart rate responses reached the minimum intensity necessary for therapeutic aerobic exercise (40%–60% heart rate reserve) or (2) heart rate responses during bouts of walking revealed excessive workload that may limit walking (>80% heart rate reserve). Eight individuals with subacute stroke attending in-patient rehabilitation were recruited. Participants wore heart rate monitors and accelerometers during a typical rehabilitation day. Walking-related changes in heart rate and walking bout duration were determined. Patients did not meet the minimum cumulative requirements of walking intensity (>40% heart rate reserve) and duration (>10 minutes continuously) necessary for cardiorespiratory benefit. Only one patient exceeded 80% heart rate reserve. The absence of significant increases in heart rate associated with walking reveals that patients chose to walk at speeds well below a level that has meaningful cardiorespiratory health benefits. Additionally, cardiorespiratory workload is unlikely to limit participation in walking. Measurement of heart rate and walking during in-patient rehabilitation may be a useful approach to encourage patients to increase the overall physical activity and to help facilitate recovery.

The effects of anterior load carriage on lower limb gait parameters during obstacle clearance

The purpose of this study was to assess the effect of anterior load carriage on obstacle-crossing behaviour, with a focus on lower limb gait parameters. Nine male participants (age 23+/-1.8 years, height 176+/-5.0cm) volunteered. Participants either walked without a load (No Load), or carried a load (2KG (empty box), 5KG, 10KG), and stepped over a 20cm obstacle. Vision of the obstacle was obscured 1.0m to 1.3m prior to the obstacle. Significant correlations were found between trail limb toe distance and lead limb toe clearance, in the 2KG, 5KG, and 10KG conditions. Toe clearance increased with load (No Load, 147.3+/-13.9mm; 2KG, 162.5+/-15.6mm; 5KG, 167.6+/-17.6mm; 10KG, 173.9+/-17.5mm; p<0.0001). Trail limb toe distance, trail limb toe distance variability, lead heel distance variability, and lead limb toe clearance variability were greater in the 2KG, 5KG, and 10KG conditions, compared with the No Load condition. Participants adopted a conservative gait pattern during obstacle crossing when carrying a load, evidenced by increasing toe clearance, which may have been influenced by availability of visual information regarding obstacle position. In contrast with previous literature, increased lead limb toe clearance may have been associated with absence of relative surface height difference pre- and post-obstacle crossing.

The perceptions of professional soccer players on the risk of injury from competition and training on natural grass and 3rd generation artificial turf.

BackgroundThe purpose of this study was to describe professional soccer players’ perceptions towards injuries, physical recovery and the effect of surface related factors on injury resulting from soccer participation on 3rd generation artificial turf (FT) compared to natural grass (NG).MethodsInformation was collected through a questionnaire that was completed by 99 professional soccer players from 6 teams competing in Major League Soccer (MLS) during the 2011 season.ResultsThe majority (93% and 95%) of the players reported that playing surface type and quality influenced the risk of sustaining an injury. Players believed that playing and training on FT increased the risk of sustaining a non-contact injury as opposed to a contact injury. The players identified three surface related risk factors on FT, which they related to injuries and greater recovery times: 1) Greater surface stiffness 2) Greater surface friction 3) Larger metabolic cost to playing on artificial grounds. Overall, 94% of the players chose FT as the surface most likely to increase the risk of sustaining an injury.ConclusionsPlayers believe that the risk of injury differs according to surface type, and that FT is associated with an increased risk of non-contact injury. Future studies should be designed prospectively to systematically track the perceptions of groups of professional players training and competing on FT and NG.

Frontal plane standing balance with an ambulation aid:Upper limb biomechanics

Despite widespread acceptance of clinical benefits, empirical evidence to evaluate the advantages and limitations of ambulation aids for balance control is limited. The current study investigates the upper limb biomechanical contributions to the control of frontal plane stability while using a 4-wheeled walker in quiet standing. We hypothesized that: (1) upper limb stabilizing moments would be significant, and (2) would increase under conditions of increased stability demand. Factors influencing upper limb moment generation were also examined. Specifically, the contributions of upper limb center-of-pressure (COP(hands)), vertical and horizontal loads applied to the assistive device were assessed. The results support a significant mechanical role for the upper limbs, generating 27.1% and 58.8% of overall stabilizing moments under baseline and challenged stability demand conditions, respectively. The increased moment was achieved primarily through the preferential use of phasic upper limb control, reflected by increased COP(hands) (baseline vs. challenged conditions: 0.29 vs. 0.72cm). Vertical, but not horizontal, was the primary force direction contributing to stabilizing moments in quiet standing. The key finding that the upper limbs play an important role in effecting frontal plane balance control has important implications for ambulation aid users (e.g., elderly, stroke, and traumatic brain injury).

The impact of post-stroke spasticity and botulinum toxin on standing balance: a systematic review

Although falls, balance impairment, and spasticity are common post-stroke, their interrelationship remains unclear. We review the literature for a) a relationship between spasticity and balance and b) the effect of botulinum toxin injections on balance. Electronic databases were searched based on two criteria: a) studies assessing balance in subjects with spasticity and b) studies examining the effect of botulinum toxin on balance. The primary findings were a) balance is impaired in subjects with spasticity, but only one study assessed relationship between spasticity and balance; and b) four studies reported that balance improves following botulinum treatment for limb spasticity. Persons with spasticity demonstrate impaired balance, but the correlation between spasticity and balance has not been adequately assessed in the literature. Evidence for balance changes following botulinum toxin is weak because of lack of randomization, control group comparison, objective balance assessment measures, and standard clinical scales.