Association Between Falls and Brain Subvolumes: Results from a Cross-Sectional Analysis in Healthy Older Adults.

Falls are a consequence of gait instability. Cortical and subcortical abnormalities have been associated with gait instability but not yet with falls. This study aims to compare the global and regional brain subvolumes between healthy older fallers and non-fallers. A total of 77 healthy older individuals (23 fallers and 54 non-fallers, 69.8 ± 3.5 years; 45.5 % female) were included in this study using a cross-sectional design. Based on an a priori hypothesis, the following brain subvolumes were quantified from three-dimensional T1-weighted MRI using FreeSurfer software: total white matter abnormalities, total white matter, total cortical and subcortical gray matter, hippocampus, motor cortex, somatosensory cortex, premotor cortex, prefrontal cortex and parietal cortex volumes. Gait performances were also recorded. Age, sex, body mass index, comorbidities, use of psychoactive drugs, far-distance visual acuity, lower-limb proprioception, depressive symptoms and cognitive scores (Mini-Mental State Examination, Frontal Assessment Battery) were used as covariates. Fallers have more frequently depressive symptoms (P = 0.048), a lower far distance visual acuity (P = 0.026) and a higher coefficient of variation of stride time (P = 0.008) compared to non-fallers. There was a trend to greater subvolumes for the somatosensory cortex (P = 0.093) and the hippocampus (P = 0.060) in the falls group. Multiple logistic regressions showed that subvolumes of the somatosensory cortex and the hippocampus (P < 0.042) were increased in fallers compared to non-fallers, even after adjustment for clinical and brain characteristics. The greater subvolumes of the somatosensory cortex and hippocampus reported in fallers compared to non-fallers suggests a possible brain compensatory mechanism involving spatial navigation and integration of sensory information.

Motoric cognitive risk syndrome, incident cognitive impairment and morphological brain abnormalities: Systematic review and meta-analysis.

BACKGROUND: Motoric cognitive risk syndrome (MCR) is a pre-dementia stage, which associates slow walking speed with subjective cognitive impairment (SCI). MCR's clinical utility for the prediction of dementia and its pathophysiology are unclear. The aim of this systematic review and meta-analysis is to examine the association of MCR with incident cognitive impairment, cognitive performance and brain structures. METHODS: A systematic search was conducted using the Medical Subject Heading terms "Walking" and "Cognition disorders" combined with the terms "Subjective cognitive impairment", "Subjective cognitive decline" and "Motoric cognitive risk". A total of 11 studies were included in the systematic review and meta-analysis: 3 studies had dementia as the outcome, 3 studies had cognitive performance as the outcome, 4 studies had brain structures as the outcome and one study examined the incidence of both major neurocognitive disorders and cognitive impairment. RESULTS: MCR was found to be associated with incident cognitive impairment (pooled hazard ratio (HR) = 1.70, 95% CI, 1.46-1.98 with P-value <0.001) and dementia (pooled HR = 2.50, 95% CI, 1.75-2.39 with P-value <0.001). MCR was also found to be associated with low grey matter volume involving the premotor and the prefrontal cortex, and lacunar lesions in the frontal lobe. No significant association was found with white matter abnormalities. CONCLUSION: MCR predicts cognitive impairment and dementia, suggesting that it may be used as a screening syndrome for dementia in a primary care setting. Its significant association with both low grey matter volume and lacunar lesions makes its pathophysiology unclear and suggests multiple pathways.

Brain gray matter volume associations with gait speed and related structural covariance networks in cognitively healthy individuals and in patients with mild cognitive impairment: A cross-sectional study.

INTRODUCTION: Gait speed is slower in patients with mild cognitive impairment (MCI) compared to cognitively healthy individuals (CHI). We examined the patterns of brain gray matter (GM) volume association and covariance with gait speed in CHI and in patients with MCI. METHODS: A total of 96 CHI and 99 patients with MCI were recruited in this cross-sectional study. Brain GM volumes measured with voxel-based morphometry and self-paced gait speed were used as outcomes. RESULTS: The right middle frontal and precentral gyri volumes were positively associated with gait speed in CHI and covariated with frontal cortex. Striatum (i.e. left putamen and bilateral caudate nuclei) volumes were positively associated with gait speed in patients with MCI and covariated with striatal structures. CONCLUSIONS: Two different patterns of brain GM volume association and covariance with gait speed were found and involving frontal cortex in CHI and the striatum in patients with MCI.

The identification of age-related differences in kinetic gait parameters using principal component analysis.

Background. The age of onset of adult-like kinetic gait patterns is controversial. A potential cause of discrepant results between studies is the statistical analyses used to test for differences in kinetic parameters between age groups. Therefore, the purpose of this study was to identify age-related differences in kinetic gait parameters across children aged 3-13 years using principal component analysis. Methods. Principal component analysis was applied to seven kinetic waveform variables (N=7) from each of four age groups (3-4 years (n=13); 5-6 years (n=10); 7-8 years (n=12); and 9-13 years (n=12)). The principal component scores for each kinetic variable were used to test for group differences using one-way ANOVA and Kruskal-Wallis tests. Findings. Significant group differences (P<0.05) were found for five of the principal component scores. Plantarflexion moments increased with age and the oldest group of children (9-13 years old) demonstrated significantly larger plantarflexor moment patterns compared to all other age groups. The 9-13 years old showed significantly larger knee flexor and extensor moments for the first half of the cycle and a later reversal to extensor moments in terminal stance compared to 3-6 years old. The older group also showed decreased hip extensor moments for the first third of the cycle and increased flexor moments in the second third of the cycle compared to the 3-4 and 7-8 years old. Larger stance phase hip abduction moments were observed in the older group compared to all other groups. This was followed by a more complex pattern of alternating moments. Hip power also showed a complex series of differences between age-groups. Interpretation. Compared to parameterization techniques, principal component analysis identified different characteristics in kinetic gait data to discriminate between paediatric age groups. This is the first study to identify age-related differences in gait kinetics using waveform analysis.

Association of Motoric Cognitive Risk Syndrome with Cardiovascular Disease and Risk Factors: Results from an Original Study and Meta-Analysis.

BACKGROUND: Motoric cognitive risk (MCR) syndrome, a recently described pre-dementia syndrome, has been associated with cardiovascular disease and their risk factors (CVDRF). OBJECTIVE: To determine whether MCR syndrome was associated with CVDRF in French community-dwelling older adults, and to quantitatively evaluate, with a systematic review and meta-analysis, the association of MCR syndrome with CVDRF. METHODS: Based on a cross-sectional design, 238 older adults without dementia were selected from the French GAIT study. An English and French systematic Medline and Embase search (without limiting date of publication) was also conducted in February 2017 using the terms "motoric cognitive risk syndrome" OR "motoric cognitive risk" OR "motoric risk". The systematic review and meta-analysis included 8 studies. CVDRF were defined as cardiovascular diseases, hypertension, diabetes, stroke, obesity and abnormal waist-hip ratio (WHR). RESULTS: The prevalence of MCR syndrome in the current original study was 16.8%. MCR syndrome was associated with abnormalWHR(Odds ratio [OR] >2.8 with p < 0.020) and high blood pressure (OR >2.5 with p < 0.025). Of the 202 originally identified abstracts, 7 (3.5%) were selected for the systematic review. The meta-analysis showed that all pooled OR were significant with a p-value <0.001 (OR = 1.41 for cardiovascular diseases, 1.21 for hypertension, 1.44 for diabetes, 2.05 for stroke, and 1.34 for obesity). When pooling all CVDRF, the overall OR was 1.38 (95% CI, 1.33-1.45) with p-value <0.001. CONCLUSION: MCR syndrome is significantly associated with CVDRF. These findings suggest that a vascular mechanism may underlie the pathophysiology of MCR syndrome.

An extended index to quantify normality of gait in children.

Clinical gait analysis aims to quantify and assess the mechanics of walking and identify deviations from 'normal' movement patterns. To facilitate the use of clinical equipment, protocols are required to process data and produce a few meaningful summary measurements which can, in turn, be used to flag gait abnormalities. Earlier work produced a one-dimensional index of gait, calculated from sagittal hip, knee and ankle rotation angle patterns. The objective of this study was to extend the original index, incorporating kinematic and kinetic data from multiple planes, while allowing for correlations between component measures. A one-dimensional index of normal gait was developed, based on normative gait data (N=45 children, aged 3-13 years). The new one-dimensional index was calculated using correlation patterns between seven component indices, each of which has diagnostic interpretation. The effectiveness of the new index was tested using immature normative data (N=14) and hypotonic data (N=10). Approximately 85% of immature normative children and 100% of hypotonic children were classified as either unusual or extreme by the one-dimensional index. These data reduction protocols improve objective gait analyses in the clinical setting.

Comparison of two normative paediatric gait databases.

The availability of age-matched normative data is an essential component of clinical gait analyses. Comparison of normative gait databases is difficult due to the high-dimensionality and temporal nature of the various gait waveforms. The purpose of this study was to provide a method of comparing the sagittal joint angle data between two normative databases. We compared a modern gait database to the historical San Diego database using statistical classifiers developed by Tingley et al. (2002). Gait data were recorded from 60 children aged 1-13 years. A six-camera Vicon 512 motion analysis system and two force plates were utilized to obtain temporal-spatial, kinematic, and kinetic parameters during walking. Differences between the two normative data sets were explored using the classifier index scores, and the mean and covariance structure of the joint angle data from each lab. Significant differences in sagittal angle data between the two databases were identified and attributed to technological advances and data processing techniques (data smoothing, sampling, and joint angle approximations). This work provides a simple method of database comparison using trainable statistical classifiers.

A comparison of kinetic gait parameters for 3-13 year olds.

BACKGROUND: Normative gait data is essential for diagnosing and treating abnormal gait patterns. The examination of the onset of adult-like kinetic gait patterns in children has generated inconsistent results. The purpose of this study was to identify age-related differences in kinematic and kinetic gait parameters across children aged 3-13 years old. METHODS: A motion capture system and three force plates were employed to compute sagittal joint angles and joint kinetics during walking and compare results between children aged 3-4 years (n=13), 5-6 years (n=10), 7-8 years (n=12), and 9-13 years (n=12). Anthropometric data was estimated using a mathematical model (elliptical cylinder method). Peak flexion and extension joint angles and moments, and peak concentric and eccentric joint powers were analyzed using multivariate analyses of variance. FINDINGS: For most of the variables examined, similar results were obtained across age groups. Reduced peak hip flexion moments and knee extension moments were observed in the 3-4 year olds compared to the oldest group of walkers. Compared to the 9-13 year olds, reduced ankle joint moments and power were observed in most age groups. INTERPRETATION: The results suggest that adult-like kinetic patterns for the hip and knee were attained by 5 years of age. However, for the ankle joint, adult-like patterns are not achieved until nine years of age or older. These findings stress the importance of using age-matched normative data for clinical gait analysis.

The relationship between hippocampal volume and static postural sway: results from the GAIT study.

The role of the hippocampus in postural control, in particular in maintaining upright stance, has not been fully examined in normal aging. This study aims to examine the association of postural sway with hippocampal volume while maintaining upright stance in healthy older individuals. Seventy healthy individuals (mean age 69.7 ± 3.4 years; 41.4 % women) were recruited in this study based on cross-sectional design. Hippocampal volume (quantified from a three-dimensional T1-weighted MRI using semi-automated software), three center of pressure (COP) motion parameters (sway area, path length of anterior-posterior (AP) and medial-lateral (ML) displacement) while maintaining upright stance (eyes open and closed), and the relative difference between open and closed eye conditions were used as outcome measures. Age, sex, body mass index, lower limb proprioception, distance vision, 15-item geriatric depression scale score, total cranial volume, and white matter abnormalities were used as covariates. The sway area decreased from open to closed eye condition but this variation was non-significant (P = 0.244), whereas path length of AP and ML displacement increased significantly (P < 0.003). Increase in sway area from open to closed eyes was associated with greater hippocampal volume (ß -18.21; P = 0.044), and a trend for an association of increase in path length of AP displacement (P = 0.075 for open eyes and P = 0.071 for closed eyes) with greater hippocampal volume was reported. The hippocampus is involved in upright postural control in normal aging, such that an increase in sway area of COP motion from open to closed eyes is associated with greater hippocampal volume in healthy older adults.

Anti-Dementia Drugs, Gait Performance and Mental Imagery of Gait: A Non-Randomized Open-Label Trial.

BACKGROUND: Few studies have examined the effect of anti-dementia drugs (i.e., acetylcholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists) on gait performance. Past studies have focused on the stride time (i.e., gait cycle duration) but not on the mental imagery of gait. OBJECTIVES: To compare mental imagery of gait and spatiotemporal gait parameters in patients with dementia [i.e., Alzheimer's disease (AD) and non-AD] before and after the use of anti-dementia drugs (i.e., acetylcholinesterase inhibitors and memantine) and in controls (i.e., patients with dementia who did not take anti-dementia drugs). METHODS: A total of 112 patients (mean age 82.5 ± 4.2 years, 68.8 % female) with mild-to-moderate AD and non-AD dementia were included in this non-randomized open-label trial (n = 56 in the Intervention group, and n = 56 in the Control group matched for age, sex, and stage and type of dementia) nested in a cohort study (mean follow-up 238.5 ± 79.8 days). Mental imagery of gait was assessed with the actual and imagined Timed Up and Go tests (aTUG and iTUG) and the difference between aTUG and iTUG (i.e., delta-TUG). Spatiotemporal gait parameters were measured with the GAITRite(®) system during normal walking. RESULTS: Participants in the Intervention group had a longer iTUG time (p < 0.001) and a lower delta-TUG value (p = 0.001) at the follow-up compared with those in the Control group. There was a significant increase in iTUG (p = 0.001) and decrease in delta-TUG (p < 0.001) from baseline to the follow-up only in the Intervention group. Multiple linear regression showed that the use of anti-dementia drugs was associated with a longer iTUG time and a lower delta-TUG value (best performance, p < 0.002). CONCLUSIONS: Our findings showed an improvement in mental imagery of gait with the use of anti-dementia drugs, but no changes in actual gait performance. TRIAL REGISTRATION: NCT01315704.

Changes in infant segment inertias during the first three months of independent walking.

BACKGROUND: During infancy, rapid changes in physical growth affect the size and shape of the body segments. To understand the effects of growth on movement, it is first necessary to quantify rates of development during the acquisition of important motor milestones. The goal of this longitudinal study was to quantify the physical growth of infant body segments during the initial stages of independent walking. METHODS: Ten infants (N = 10) aged between 28 and 55 weeks at the beginning of the study were tested biweekly (every two weeks) for three months. A 13-segment mathematical model of the human body was used to estimate the inertial parameters of the infant body segments at each session. An analysis of variance was used to test for significant differences in segment masses between biweekly measures. Polynomial contrasts were used to test for linear trends in the growth data. RESULTS: Significant differences between biweekly measures of segment mass were found only for the head/neck (F(5,45) = 3.42, p < 0.05), upper trunk (F(5,45) = 4.04, p < 0.01), and lower trunk (F(5,45) = 3.49, p < 0.01). The lower trunk demonstrated a linear increase in mass (F(1,9) = 4.56, p < 0.05). However, the upper trunk demonstrated a quadratic trend in growth (F(1,9) = 9.13, p < 0.01), while the head/neck segment showed a cubic trend in growth (F(1,9) = 3.80, p < 0.05). Significant differences in axial segment masses were also found between subjects (F(9,45) = 5.92, p < 0.001). CONCLUSION: Given that postural control proceeds in a cephalocaudal manner, the lower trunk segment would be brought under control last, in terms of the axial segments. Increases in the mass of this segment could constrain the system, thereby acting as a control parameter for the onset and development of motor patterns.

Gait analysis.

Gait analysis, or the study of locomotion, has changed dramatically over the last few decades. Advances in computer technology and data analysis techniques have contributed greatly to the progress of this field. Gait analysis has become a valuable tool in the clinical setting. The ability to objectively quantify motion is essential to our understanding of normal and abnormal movement patterns and the evaluation of treatment effectiveness. This paper will discuss the various experimental and analytical techniques currently used for performing clinical gait analyses at the University of New Brunswick, Fredericton, New Brunswick, Canada.

Comparison of bilateral and unilateral contractions between swimmers and nonathletes during leg press and hand grip exercises.

The bilateral limb deficit (BLD) is defined as the reduction in force production during bilateral compared with summed unilateral contractions of homologous muscles. The underlying mechanism for the BLD has been elusive to determine. The purpose of this study was to examine the presence of the BLD during maximal isometric leg press and handgrip exercises in female swimmers (n = 9, mean age = 20.1 ± 1.3 years) and nonathletes (n = 9, mean age = 21.7 ± 1.3 years) to gain further insight into this phenomenon. Force and electromyography (EMG) measures were collected from participants under bilateral and unilateral conditions for handgrip and leg press exercises. Bilateral limb ratios (BLR) were calculated for swimmers (BLRS) and nonathletes (BLRNA). A deficit was found for swimmers and nonathletes in leg force (BLRS = 79.84% ± 13.09% and BLRNA = 81.44% ± 19.23%) and leg EMG (BLRS = 88.45% ± 15.41% and BLRNA = 94.66% ± 13.62%); however, no BLD was seen in hand force (BLRS = 98.30% ± 11.21% and BLRNA = 95.91% ± 11.04%) and hand EMG (BLRS = 102.42% ± 11.20% and BLRNA = 103.30% ± 16.50%). Furthermore, no significant differences were found between groups for leg force, leg EMG, hand force, and hand EMG. In conclusion, a BLD was detected for both groups during bilateral isometric leg press. This suggests that while the BLD may be affected by neural influences, there may other factors involved such as postural stability requirements to perform the exercise.

Gait symmetry in children with autism.

Most studies examining gait asymmetry have focused on infants and toddlers and have tended to use subjective methods of evaluating movement. No previous studies have examined gait symmetry in older children with autism using objective motion capture systems. The purpose of this paper was to quantify gait symmetry in children with autism versus age-matched controls. Fourteen children with autism (N = 14) and twenty-two (N = 22) age, height, and weight-matched controls participated in the study. An eight camera Vicon motion capture system and four Kistler force plates were used to compute temporal-spatial parameters and symmetry indices during walking. Group differences in these measures were tested using MANOVAs. No significant differences between the autism and control group were found for any of the temporal-spatial measures or symmetry indices. Therefore, results suggest that children with autism demonstrate typical symmetry or interlimb movement during gait. Further research is needed to examine the use of different gait inputs to the symmetry indices (e.g., joint angles and moments). A greater awareness of the movement patterns associated with autism may increase our understanding of this disorder and have important implications for treatment planning.

Multisegment foot kinematics during walking in younger and older adults.

BACKGROUND: Currently, age-related changes in foot mechanics are poorly understood. A greater understanding of the natural changes in foot motion is needed to improve our understanding of pathological foot conditions. METHODS: The purpose of this study was to compare multisegment foot kinematic data during gait in younger and older individuals. Eleven (N = 11) adult male participants between the ages of 18 - 30 years (younger group; mean ± SD: 24.6 ± 3.0 years) and eleven (N = 11) adults aged 55 years or older (older group; mean ± SD: 65.0 ± 4.2 years) were recruited for the study. The foot was modeled as a four-segment rigid body model. Three-dimensional kinematic and kinetic gait parameters were recorded using an 8-camera Vicon MCam motion capture system and two Kistler force plates. A MANOVA was used to test for significant differences in mean temporal-spatial data, mean ranges of motion, and mean peak joint angle data between age groups. RESULTS: No significant differences (P > 0.05) were found between the two age groups for any of the gait parameters. The results of the present study suggest that individuals aged 65.0 ± 4.2 years have foot mechanics that are comparable to younger walkers. CONCLUSIONS: As such, any deviations in motion at this age may be indicative of an underlying disease or disorder.

Gait patterns in children with autism.

BACKGROUND: Very few studies have examined the gait patterns of children with autism. A greater awareness of movement deviations could be beneficial for treatment planning. The purpose of this study was to compare kinematic and kinetic gait patterns in children with autism versus age-matched controls. METHODS: Twelve children with autism and twenty-two age-matched controls participated in the study. An eight camera motion capture system and four force plates were used to compute joint angles and joint kinetics during walking. Parametric analyses and principal component analyses were applied to kinematic and kinetic waveform variables from the autism (n=12) and control (n=22) groups. Group differences in parameterization values and principal component scores were tested using one-way ANOVAs and Kruskal-Wallis tests. FINDINGS: Significant differences between the autism and control group were found for cadence, and peak hip and ankle kinematics and kinetics. Significant differences were found for three of the principal component scores: sagittal ankle moment principal component one, sagittal ankle angle principal component one, and sagittal hip moment principal component two. Results suggest that children with autism demonstrate reduced plantarflexor moments and increased dorsiflexion angles, which may be associated with hypotonia. Decreased hip extensor moments were found for the autism group compared to the control group, however, the clinical significance of this result is unclear. INTERPRETATION: This study has identified several gait variables that were significantly different between autism and control group walkers. This is the first study to provide a comprehensive analysis of gait patterns in children with autism.