Pathophysiology of Gait Disturbance in Neurologic Disorders and Clinical Presentations

Estimation of minimum foot clearance using a single foot-mounted inertial sensor and personalized foot geometry scan

The real-world measurement of minimum foot clearance (mFC) during the swing phase of gait is critical in efforts to understand and reduce the risk of trip-and-fall incidents in populations with gait impairments. Past research has focused on measuring clearance of a single point on a person's foot, typically the toe-however, this may overestimate mFC and may even be the wrong region of the foot in cases of gait impairments or interventions. In this work, we present a novel method to reconstruct the swing-phase trajectory of an arbitrary number of points on a person's shoe and estimate the instantaneous height and location of whole-foot mFC. This is achieved using a single foot-mounted inertial sensor and personalized shoe geometry scan, assuming a rigid-body IMU-shoe system. This combination allows collection and analysis using out-of-lab tests, potentially including clinical environments. Validation of single marker location using the proposed method vs. motion capture showed height errors with bias less than 0.05 mm, and 95% confidence interval of - 8.18 to + 8.09 mm. The method is demonstrated in an example data set comparing different interventions for foot drop, and it shows clear differences among no intervention, functional electrical stimulation, and ankle-foot orthosis conditions. This method offers researchers and clinicians a rich understanding of a person's gait by providing objective 3D foot kinematics and allowing a unique opportunity to view the regions of the foot where minimum clearance occurs. This information can contribute to a more informed recommendation of specific interventions or assistive technology than is currently possible in standard clinical practice.

Mobility Rehab visual feedback system for gait rehabilitation in older adults

BACKGROUND

Gait and balance impairments are among the main causes of falls in older adults. The feasibility and effectiveness of adding sensor-based feedback to physical therapy (PT) in an outpatient PT setting is unknown. We evaluated the feasibility and effectiveness of PT intervention combined with a therapist-assisted visual feedback system, called Mobility Rehab, (PT + MR) in older adults.

METHODS

Twenty-eight older adults with and without neurological diseases were assigned either PT + MR (n = 22) or PT alone (n = 6). Both groups performed 8 sessions (individualized) of 45 min long (30 min for gait training and 15 min for endurance, strength, and balance exercises) in an outpatient clinic. Mobility Rehab uses unobtrusive, inertial sensors on both wrists and feet, and at the sternum level with real-time algorithms to provide real-time feedback on five gait metrics (step duration, stride length, elevation at mid-swing, arm swing range-of-motion [ROM], and trunk coronal ROM), which are displayed on a tablet. The primary outcome was the Activities-specific Balance Confidence scale (ABC). The secondary outcome was gait speed measured with wearable inertial sensors during 2 min of walking.

RESULTS

There were no between-group differences at baseline for any variable (P > 0.05). Neither PT + MR nor PT alone showed significant changes on the ABC scores. PT + MR, but not PT alone, showed significant improvements in gait speed and arm swing ROM. The system was evaluated as 'easy to use' by the PT.

CONCLUSIONS

Our preliminary results show that PT + MR improves gait speed in older adults with and without neurological diseases in an outpatient clinic.

CLINICAL TRIAL REGISTRATION

www.

CLINICALTRIALS

gov , identifier: NCT03869879.

Spasticity distribution and severity in individuals with HTLV-1-associated myelopathy/tropical spastic paraparesis

In individuals with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), spasticity is one of the main symptoms. The neurological signs of the disease are well defined, but details of how spasticity appears in these individuals have not been well explored. To describe spasticity location and severity of HAM/TSP individuals. Cross-sectional study with individuals older than 18 years, diagnosed with HAM/TSP and with lower limb spasticity. Pregnant women, individuals with other associated neurological diseases, and those using antispastic drugs were not included. Spasticity was assessed by the Modified Ashworth Scale (MAS), applied to the abductor, adductor, flexor, and extensor muscles of the hips, flexors, and extensors of the knees, dorsiflexors, plantiflexors, evertors, and inverters of the foot. Thirty participants were included. The plantiflexor muscles (90%), knee extensors (80%), knee flexors (63,3%), and adductors (50%) were most frequently affected by spasticity. Twenty-three (76.7%) individuals had mixed spasticity, 5 (16.7%) with distal spasticity and 2 (6.7%) with proximal spasticity. MAS was similar between the lower limbs in at least 6 of the 10 muscle groups of each individual. Spasticity was mostly mixed in the lower limbs, with more frequently mild severity. The individuals were partially symmetrical between the lower limbs. The most affected muscle groups were the plantiflexors, knee extensors and flexors and the hip adductors, consecutively, being predominantly symmetrical.

Age-related differences in interlimb coordination during typical gait: An observational study

BACKGROUND

Arm movements during gait are known to alter with increasing age during the slow maturation phase (>3years). It is unclear whether coordination between the arms and legs (i.e. interlimb coordination), which is a measure of gait quality, shows a similar pattern.

RESEARCH QUESTION

to investigate age-related differences in interlimb coordination during gait in typically developing children and adults.

METHODS

In this observational study, 98 typically developing participants were divided into five age-groups: preschool children (G1; 2.9-5.9 years[n = 18]), children (G2; 6.0-9.9 years[n = 22]), pubertal children (G3; 10.0-13.9 years[n = 26]), adolescents (G4; 14.0-18.9 years[n = 14]) and adults (G5; 19.0-35.2 years[n = 18]). Participants walked barefoot at a self-selected walking speed along a 10-m walkway during three-dimensional total-body gait analysis. To examine interlimb coordination, mean continuous relative phase over the gait cycle (MRP) and its variability (sdMRP) were calculated for each combination of limb pairs in the sagittal plane.

RESULTS

MRP increased towards more anti-phase coordination with increasing age in following limb pair combinations: left arm-right arm (median[interquartile range]; G1: 152.0°[126.6;160.7°]-G5: 171.5°[170.0;175.3°]), left arm-left leg (G1: 155.0°[131.3;167.6°]-G5: 170.8°[165.3;173.5°]) and right arm-right leg (G1: 155.7°[135.5;166.0°]-G5: 170.0°[166.4;173.5°]). MRP decreased towards more in-phase coordination from G1 to G5 in left arm-right leg (G1: 24.4°[15.3;45.8°]-G5: 10.5°[6.1;15.6°]) and right arm-left leg (G1: 25.0°[13.7;41.1°]-G5: 9.7°[5.2;16.8°]). sdMRP decreased from G1 to G5 for all limb pair combinations.

SIGNIFICANCE

Interlimb coordination altered with increasing age. First, coordination between the legs and right arm-left leg appeared mature in G1 (aged 2.9-5.9 years). Next, coordination between the ipsilateral limbs seemed mature at 9.9 years, followed by a mature coordination between left arm-right leg at 13.9years. Coordination between the two arms showed ongoing differences until adulthood. These data provide an age-related framework and normative dataset to distinguish age-related differences from pathology in children with neuromotor disorders in clinical practice.

Accuracy Verification of Spatio-Temporal and Kinematic Parameters for Gait Using Inertial Measurement Unit System

Inertial measurement unit systems are wearable sensors that can measure the movement of a human in real-time with relatively little space and high portability. The purpose of this study was to investigate the accuracy of the inertial measurement unit (IMU) system for gait analysis by comparing it with measurements obtained using an optical motion capture (OMC) system. To compare the accuracies of these two different motion capture systems, the Spatio-temporal and kinematic parameters were measured in young adults during normal walking. Thirty healthy participants participated in the study. Data were collected while walking 5 strides on a 7 m walkway at a self-selected speed. Results of gait analysis showed that the Spatio-temporal (stride time, stride length, cadence, step length) and kinematic (knee joint peak to peak of movement) parameters were not significantly different in the participant. Spatio-temporal and kinematic parameters of the two systems were compared using the Bland–Altman method. The results obtained showed that the measurements of Spatio-temporal and kinematic parameters of gait by the two systems were similar, which suggested that IMU and OMC systems could be used interchangeably for gait measurements. Therefore, gait analysis performed using the wearable IMU system might efficiently provide gait measurements and enable accurate analysis.

Changes in Gait Parameters and Gait Variability in Young Adults during a Cognitive Task while Slope and Flat Walking

This study investigates the effects of a cognitive task while walking on a slope or a flat surface on gait parameters and gait variability in young adults. The participants consisted of thirty healthy young subjects. They were instructed to walk on a slope or on a flat surface while performing or not performing a cognitive task, which involved speaking a four-syllable word in reverse. A wearable inertia measurement unit (IMU) system was used to measure spatiotemporal parameters and gait variability. Flat gait (FG) while performing the cognitive task (FGC) and uphill gait (UG) while performing the cognitive task (UGC) significantly altered stride times, gait speeds, and cadence as compared with FG and UG, respectively. Downhill gait (DG) while performing the cognitive task (DGC) caused no significant difference as compared with DG. Gait variability comparisons showed no significant difference between UGC and UG or between FGC and FG, respectively. On the other hand, variabilities of stride times and gait speeds were significantly greater for DGC than DG. FGC and UGC induce natural changes in spatiotemporal gait parameters that enable the cognitive task to be performed safely. DGC should be regarded as high complexity tasks involving greater gait variability to reduce fall risk.

The long-term effects of an implantable drop foot stimulator on gait in hemiparetic patients

Drop foot is a frequent abnormality in gait after central nervous system lesions. Different treatment strategies are available to functionally restore dorsal extension during swing phase in gait. Orthoses as well as surface and implantable devices for electrical stimulation of the peroneal nerve may be used in patients who do not regain good dorsal extension. While several studies investigated the effects of implanted systems on walking speed and gait endurance, only a few studies have focussed on the system’s impact on kinematics and long-term outcomes. Therefore, our aim was to further investigate the effects of the implanted system ActiGait on gait kinematics and spatiotemporal parameters for the first time with a 1-year follow-up period. 10 patients were implanted with an ActiGait stimulator, with 8 patients completing baseline and follow-up assessments. Assessments included a 10-m walking test, video-based gait analysis and a Visual Analogue Scale (VAS) for health status. At baseline, gait analysis was performed without any assistive device as well as with surface electrical stimulation. At follow-up patients walked with the ActiGait system switched off and on. The maximum dorsal extension of the ankle at initial contact increased significantly between baseline without stimulation and follow-up with ActiGait (p = 0.018). While the spatio-temporal parameters did not seem to change much with the use of ActiGait in convenient walking speed, patients did walk faster when using surface stimulation or ActiGait compared to no stimulation at the 10-m walking test at their fastest possible walking speed. Patients rated their health better at the 1-year follow-up. In summary, a global improvement in gait kinematics compared to no stimulation was observed and the long-term safety of the device could be confirmed.

Brain activity during walking: A systematic review

BACKGROUND

This systematic review provides an overview of the literature deducing information about brain activation during (1) imagined walking using MRI/fMRI or (2) during real walking using measurement systems as fNIRS, EEG and PET.

METHODS

Three independent reviewers undertook an electronic database research browsing six databases. The search request consisted of three search fields. The first field comprised common methods to evaluate brain activity. The second search field comprised synonyms for brain responses to movements. The third search field comprised synonyms for walking.

RESULTS

48 of an initial yield of 1832 papers were reviewed. We found differences in cortical activity regarding young vs. old individuals, physically fit vs. physically unfit cohorts, healthy people vs. patients with neurological diseases, and between simple and complex walking tasks.

CONCLUSIONS

We summarize that the dimension of brain activity in different brain areas during walking is highly sensitive to task complexity, age and pathologies supporting previous assumptions underpinning the significance of cortical control. Many compensation mechanisms reflect the brain's plasticity which ensures stable walking.