Underwater gait analysis in Parkinson’s disease

Although hydrotherapy is one of the physical therapies adopted to optimize gait rehabilitation in people with Parkinson disease, the quantitative measurement of gait-related outcomes has not been provided yet. This work aims to document the gait improvements in a group of parkinsonians after a hydrotherapy program through 2D and 3D underwater and on land gait analysis. Thirty-four parkinsonians and twenty-two controls were enrolled, divided into two different cohorts. In the first one, 2 groups of patients underwent underwater or land based walking training; controls underwent underwater walking training. Hence pre-treatment 2D underwater and on land gait analysis were performed, together with post-treatment on land gait analysis. Considering that current literature documented a reduced movement amplitude in parkinsonians across all lower limb joints in all movement planes, 3D underwater and on land gait analysis were performed on a second cohort of subjects (10 parkinsonians and 10 controls) who underwent underwater gait training. Baseline land 2D and 3D gait analysis in parkinsonians showed shorter stride length and slower speed than controls, in agreement with previous findings. Comparison between underwater and on land gait analysis showed reduction in stride length, cadence and speed on both parkinsonians and controls. Although patients who underwent underwater treatment exhibited significant changes on spatiotemporal parameters and sagittal plane lower limb kinematics, 3D gait analysis documented a significant (p < 0.05) improvement in all movement planes. These data deserve attention for research directions promoting the optimal recovery and maintenance of walking ability.     

Non-motor predictors of freezing of gait in Parkinson’s disease

BackgroundThe etiology of freezing of gait in Parkinson’s disease (PD) is yet to be clarified. Non-motor risk factors including cognitive impairment, sleep disturbance and mood disorders have been shown in freezing of gait.Research questionWe aimed to determine the predictive value of non-motor features in freezing of gait development.MethodsData were obtained from the Parkinson’s Progression Markers Initiative. Fifty PD patients with self-reported freezing of gait, and 50 PD patients without freezing of gait at the fourth year visit were included. Groups were matched for Movement Disorders Society-Unified Parkinson’s Disease Rating Scale Part III scores. Several cognitive and non-cognitive tests were used for non-motor features at baseline and over time. Executive function, visuospatial function, processing speed, learning and memory tests were used for cognition. Non-cognitive tests included sleepiness, REM sleep behavior disorder, depression and anxiety scales.ResultsPatients with freezing of gait had higher scores on sleepiness, REM sleep behavior disorder, depression and anxiety scales. However, predictor model analysis revealed that baseline processing speed, learning and sleepiness scores were predictive of self-reported freezing of gait development over time.SignificanceOur findings suggest that specific cognitive deficits and sleep disorders are predictive of future freezing of gait. These features may be helpful in identifying underlying networks in freezing of gait and should be further investigated with neuroimaging studies.     

Fractal analysis of gait in people with Parkinson’s disease: three minutes is not enough

BackgroundThe fractal dynamics of gait variability in people with Parkinson’s disease has been studied by applying the detrended fluctuation analysis (DFA) to short time series (<200 strides). However, DFA is sensitive to time series length, and it is unclear if DFA results from short time series are reliable and if they reflect the fractal dynamics of longer time series.Research questionIs DFA reliable when applied to short time series?MethodsWe applied DFA to stride time series from five 3-min trials and one 15-min trial in 12 people with Parkinson’s disease, 14 healthy older adults and 14 healthy young adults walking overground. Within each group, intraclass correlations (ICC 3,1) were performed to assess the reliability of i) the five 3-min trials together, ii) each 3-min trials to the 15-min trial, and iii) the first 150 strides from the 15-min trial to the full 15-min trial.ResultsOur three main findings are that 1) stride time α-DFA values are not consistent from trial-to-trial for short stride time series, 2) stride time α-DFA values from each 3-min trials are not consistent when compared to stride time α-DFA values from a 15-min trial, and 3) stride time α-DFA values from the first 150 strides of the 15-min trial are not consistent when compared to α-DFA values from the full 15-min trial.SignificanceOur results confirm that α-DFA values from 3-min walking trials are not reliable, and that they do not reflect the scale invariant properties of longer time series. This suggests that previous studies assessing the fractal dynamics of gait variability from about 3-min walking must be interpreted with caution. A major clinical implication is that DFA cannot be used to study gait in people unable to perform 500 strides continuously.     

Test-retest reliability of stride length-cadence gait relationship in Parkinson’s disease

IntroductionThe gait pattern in Parkinson´s disease (PD) subjects is characterized by a specific deficit of the internal regulation of the stride length (SL), while the control of the cadence (Cad) remains intact. The purpose of the present study was to evaluate the reliability of the stride length-cadence relationship (SLCrel) in a group of PD subjects.MethodsThirty five PD subjects performed two sessions, separated by a three month resting period. In each session Gait speed, SL and Cad were evaluated at five different self-selected speed conditions: preferred, slow, very slow, fast and very fast. Linear regression analysis was used to explore the SLCrel and to determine the slope, intercept and coefficient of determination (R²) for each participant. Test-retest reliability for the slope and intercept was calculated using intra-class correlation coefficient (ICC), 95% confidence interval (CI), and standard error of mean (SEM).ResultsThere were no significant differences in the slope and intercept between the two sessions. The overall speed was significantly faster in the second session compared with the first one (F = 4.60, p = 0.03). The SLCrel showed high reliability across the sessions (ICC = 0.89 and ICC = 0.91; 95% CI = 0.80−0.95 and 95% CI = 0.82−0.95; SEM = 0.002 and SEM = 0.073, for the slope and interception, respectively).ConclusionsThe SLCrel in Parkinsonian gait is a reproducible measure across a period of three months, and may be a useful tool to explore the specificity of gait rehabilitation interventions in PD subjects.     

Differences in predictors for gait speed and gait endurance in Parkinson’s disease

IntroductionBoth gait speed and gait endurance directly impact independence and community engagement for individuals with Parkinson’s disease (PD). However, factors accounting for variability in gait speed and gait endurance performance are unclear. The purpose of this study was to investigate whether key factors associated with gait speed in individuals with PD also predicted gait endurance.MethodsCommunity dwelling ambulatory individuals with PD were recruited for a single session. Key measures included 10 Meter Walk Test (10MWT) and 6 Minute Walk Test (6MWT) and key factors: age, disease severity [Movement Disorders Society United Parkinson’s Disease Rating Scale (motor scale only) (MDS-UPDRS motor)], plantar flexor strength [Calf Raise Senior (CRS)], fatigue [Fatigue Severity Scale (FSS)], cognition [Montreal Cognitive Assessment (MoCA)], and balance [Four Square Step Test (FSST)]. Multiple linear regression analyses were conducted to determine clinical relationships.ResultsSeventy-two individuals with PD (mean (standard deviation) (age = 70.83 (7.91) years; 50 males; MDS-UPDRS motor = 30.67 (13.50)) completed all assessments. The model predicting gait speed was significant, F(6, 65) = 15.143, p <.001, accounting for 54 % of the variance. Of the predictor variables age, MDS-UPDRS motor, CRS, MoCA and FSST scores were significant predictors. The model predicting gait endurance was significant, F(6, 65) = 15.608, p <.001, accounting for 55 % of the variance. Of the predictor variables, age, MDS-UPDRS motor scale, and CRS scores were significant predictors.DiscussionGait speed and gait endurance are similarly influenced by age, motor impairment, and plantarflexion strength. However, cognition and balance were predictors only of gait speed, which may suggest unique task differences exist between gait speed and gait endurance.     

The effects of habitual footwear in gait outcomes in people with Parkinson’s disease

Background: Gait is impaired in individuals with Parkinson's disease (PD). Although the effect of habitual footwear on gait spatiotemporal parameters has already been established in neurologically healthy individuals, its effects on people with PD is unknown.Research question: This study aimed to investigate the impact of habitual footwear on the step spatiotemporal parameters in people with PD.Methods: Sixteen individuals with PD (G-PD) and 15 neurologically healthy individuals (G-HC) were assessed. Participants walked on an 8 m long pressure sensitive walkway at their preferred speed with and without their habitual footwear (3 trials per condition). Footwear included flip-flops, shoes, sneakers and sandals. The average, variability and asymmetry for step length, width, duration, and velocity and the percentage time in the swing and stance phases were calculated.Results: The results showed in both groups a reduced percentage time in the swing phase and an increased step width, duration and length with footwear (F(1,29)>5.64; p<0.02). Additionally, habitual footwear increased step width variability in G-PD and G-HC (F(1,29)=3.97; p=0.06). Interestingly, only G-HC showed a higher step length asymmetry in the footwear condition than in the barefoot condition (p=0.02). Finally, only when habitual footwear was used, G-HC showed a higher step velocity asymmetry than G-PD (p=0.04).Significance: These results indicate a negative influence of footwear on gait spatiotemporal parameters in both groups. Furthermore, footwear induced differences between groups. These findings indicate that footwear use is an influencing factor in studies comparing people with PD and healthy elderly. Further data are needed before definitive recommendations are made.     

Cortical activation during gait adaptability in people with Parkinson’s disease

BackgroundPeople with Parkinson’s disease (PD) have difficulties adapting their gait. While underlying neural mechanisms involving the prefrontal cortex (PFC) have been studied across various complex walking tasks, less is known about the premotor cortex (PMC) and supplementary motor area (SMA), key cortical regions for motor planning. This study compared frontal cortical regions activation patterns using functional near-infrared spectroscopy (fNIRS), between people with PD and healthy controls (HC) during gait adaptability tasks.MethodsForty-nine people with PD (mean (SD) age: 69.5 (7.9) years) and 21 HC (69.0 (5.9) years) completed a simple walk and three randomly presented gait adaptability tasks: (i) stepping on targets, (ii) avoiding obstacles and (iii) negotiating both targets and obstacles. Cortical activity in the dorsolateral PFC (DLPFC), SMA and PMC were recorded using fNIRS. Step length, velocity and accuracy and cortical activity were contrasted between the groups and walking conditions.ResultsCompared with the HC, the PD group exhibited greater PMC activation and walked significantly slower and took shorter steps in all conditions. A statistically significant group by condition interaction indicated an increase in DLPFC cortical activation in the HC participants when undertaking the obstacle avoidance task compared with the simple walk but no increase in cortical activation in the PD group when undergoing this more challenging gait task.ConclusionsOur findings suggest people with PD have little or no DLPFC, SMA and PMC capacity beyond what they need for simple walking and in consequence need to slow their gait velocity to meet the demands of target stepping and obstacle avoidance tasks. Such behavioral and neural patterns appear consistent with concepts of compensatory over-activation and capacity limitation.     

Which model best assesses gait in healthy elderly? A confirmatory factor analysis of existing conceptual gait models

BackgroundVarious conceptual gait models have been created with exploratory factor analysis to assess gait performance in healthy individuals or patients with orthopaedic or neurological diseases. However, a direct comparison between these models, to determine which is best for assessing gait in healthy elderly subjects, has never been performed. Confirmatory factor analysis is a statistical technique which allows to compare the structure of these models and to evaluate their validity and reliability.Research questionWhich of the current models for evaluating gait shows the best construct, convergent and discriminant validity and reliability when replicated in a sample of healthy elderly subjects?Methods92 healthy elderly subjects (aged 73.3 ± 6.8 years) were enrolled. Participants were instructed to walk on a baropodometric walkway; gait variables were then extracted and analyzed according to 8 different gait models (published between 2007 and 2019). Correlation between variables of each model were investigated. The number of factors to include for each model was assessed with different criteria of principal component analysis. The construct validity of the gait models was assessed in terms of goodness of fit indexes through confirmatory factor analysis. Convergent and discriminant validity and reliability of the models were also assessed.ResultsOf the models considered, only our model previously created for patients with Parkinson’s Disease reached convergence, with an excellent fit in all indexes (χ² = 18.34, df = 13, p = 0.15, RMSEA = 0.06 (95%CI = 0.00-0.13), CFI = 0.98, TLI = 0.96, SRMR = 0.05). The model showed an acceptable convergent validity. The three factors resulted to be mutually independent (correlations among factors <0.85) and reliable. Most of the other seven considered models presented a high number (12.5-65%) of highly inter-related variables and more factors than necessary.SignificanceFuture studies can use our gait model as a framework for clinical practice or research.     

Construct validity and test-retest reliability of a free mobile application for spatio-temporal gait analysis in Parkinson’s disease patients

BackgroundMobile applications may be used to assess gait pattern deviation through mobile smartphones in people with Parkinson’s disease (PD). However, few studies have investigated their psychometrics properties.Research questionTo study the construct validity and test-retest reliability of the RUNZI® free mobile application in people with mild to moderate PD.MethodsThirty individuals were evaluated with the RUNZI® app and with the 10-meter walking test (10 MW), simultaneously. In addition, the Timed Up & Go test (TUG), Tinetti scale, and the Berg Balance Scale (BBS) were used to study the construct validity. Also, test-retest reliability of the mobile for spatio-temporal gait parameters was explored.ResultsThe correlation indices of the 10 MW test with the RUNZI® app at fast speeds was moderate to excellent (r = .588–.957). At a comfortable speed, the correlation was excellent for walking speed (r = 0.944), moderate for steps (r = 0.780) and stride length (r = 0.760), and poor for cadence (r = .424). Results showed significant correlations between TUG and spatio-temporal gait parameters at fast and comfortable speeds. There were no significant correlations or consistent associations between Tinetti and BBS and RUNZI®. The test-retest reliability was good to excellent for parameters measured with the RUNZI®.SignificanceOur findings highlight specific opportunities for a free smartphone-based spatio-temporal gait analysis to serve as a complement to conventional gait analysis methods in clinical practice with a moderate to excellent construct validity with the 10 MW test and good to excellent test-retest reliability in PD patients.     

Effect of subthalamic nucleus deep brain stimulation on balance in Parkinson’s disease: A static posturographic analysis

BackgroundThe effect of subthalamic deep brain stimulation on balance in Parkinson’s disease remains unclear.ObjectiveTo evaluate the effect of subthalamic nucleus stimulation on balance in Parkinson’s disease using posturography.Methods16 patients (9 women) who underwent subthalamic deep brain stimulation [mean age 59.6 years (46–70); mean disease duration 15.6 years (7–25); mean duration of subthalamic stimulation 32.1 months (3.0–69.6)] and 13 healthy age-matched controls were evaluated using a static posturography analysis. Patients were assessed under four conditions: 1) off medication/off stimulation; 2) off medication/on stimulation; 3) on medication/off stimulation and 4) on medication/on stimulation in ten experimental paradigms, some reproducing common situations of daily living. The displacement of the centre of pressure was analyzed using 14 posturographic parameters. The Mann-Whitney test was used to compare patients with controls. The Wilcoxon signed rank test was used to compare patients under different clinical conditions.ResultsPatients off medication/off stimulation showed larger and more rapid displacements of the centre of pressure than controls in most paradigms (p < 0.05), particularly when performing a dual task. Subthalamic stimulation alone reduced the lateral excursion and anterior-posterior velocity of the centre of pressure in quite stance paradigms (p < 0.05). Subthalamic stimulation combined with antiparkinsonian medication did not induce statistically significant changes in posturagraphic measures in any experimental paradigm.ConclusionsAlthough subthalamic stimulation alone may induce some positive effect on balance, subthalamic stimulation in addition to antiparkinsonian medication, which is the usual treatment in clinical practice, did not modify balance as assessed by static posturography in patients with Parkinson’s disease.     

Increased foot strike variability during turning in Parkinson’s disease patients with freezing of gait

BackgroundTurning is a common trigger for freezing episodes in patients with Parkinson’s disease (PD). Freezing during turning can lead to falls and fractures and decreased quality of life.Research questionDoes foot-strike contact variability also increase during turning, as previously reported in straight gait in PD patients with Freezing of Gait (FOG)?MethodsSubjects were instructed to walk on a gait mat, making “normal pivot” (180°) turns at each end. ProtoKinetics Movement Analysis Software (PKMAS) software was used for analysis. Video recordings and foot-pressure-prints were studied to identify and define turn segments. Spatiotemporal gait and turn measures were then determined only for the turn segments. A movement disorders neurologist determined clinical freezes.Results100 subjects (28 controls, 38 noFOG and 34 FOG) were included. Compared to non-freezers (noFOG), FOG subjects had a smaller foot-strike during turning (a measure of completeness of foot contact with the mat) and increased foot-strike variability. FOG subjects also had a shorter stride-length, slower stride-velocity, and greater swing phase time and percentage during turns. After adjusting for turn direction, inner/outer leg dynamics showed heavier inner leg footsteps in FOG subjects. 38% of FOG subjects experienced freezes during turning. 69% of freezes occurred during the middle third of the turn. Turn-freezers had more severe spatiotemporal gait deficits.SignificanceDeveloping targeted therapies to retrain subjects to plant their whole foot on the ground with more consistency could help decrease episodes of freezing of gait.     

Spectral analysis of body movement during deep brain stimulation in Parkinson’s disease

BackgroundThe characteristics of Parkinson’s disease (PD) include postural instability and resting tremor. However, reductions of tremor amplitude do not always improve postural stability.Research questionWhat is the effect of deep brain stimulation (DBS) of the subthalamic nucleus (STN) on spectral analysis of body movement in patients with PD when tested without anti-PD medication? The effect of visual cues was also studied.MethodsTen patients with PD (mean age 64.3 years, range 59−69 years) and 17 control participants (mean age 71.2 years, range 65–79 years) were recruited. Spectral power following a period of quiet stance (35 s) was analysed in three different spectral power bands (0−4 Hz, 4−7 Hz and 7−25 Hz). Motion markers were secured to the head, shoulder, hip, and knee, which recorded movements in two directions, the anteroposterior and lateral.ResultsDBS STN significantly changed the spectral distribution pattern across the body in the anteroposterior (p = 0.029) and lateral directions (p ≤ 0.003). DBS predominantly reduced spectral power at the head (p ≤ 0.037) and shoulder (p ≤ 0.031) in the lateral direction. The spectral power of the lower and upper body in patients with PD, with DBS ON, were more similar to the control group, than to DBS OFF. Visual cues mainly reduced spectral power in the anteroposterior direction at the shoulder (p ≤ 0.041) in controls and in patients with PD with DBS ON.SignificanceThere is an altered postural strategy in patients with PD with DBS ON as shown by an altered spectral power distribution pattern across body segments and a reduction of spectral power in the lateral direction at the head and shoulder. A reduction of spectral power in controls and in patients with PD with DBS ON suggests that visual cues are able to reduce spectral power to some extent, but not with DBS OFF where postural sway and power are larger.     

Muscular activation changes in lower limbs after underwater gait training in Parkinson’s disease: A surface emg pilot study

BackgroundUnder water gait training (UT) has been proposed as an innovative rehabilitative strategy for the treatment of axial disorders in Parkinson Disease (PD) patients, in particular for balance and gait impairment. However, the basis for the improvement is unclear.Research questionThe aim of this study was to evaluate improvements in the muscular activation in the lower limbs in a cohort of PD patients after UT.MethodsTen PD participants in the “off” state and 10 controls (mean ± standard deviation of age and BMI were respectively: 71 ± 6 years, 28 ± 3 kg/m²; 65.5 ± 7 years, 28 ± 3 kg/m²) were enrolled in the study. After signing informed consent, they walked barefoot at their preferred speed on a 10 m walkway, before and after UT. The electrical activity of four muscles were collected bilaterally by means of a surface electromyography system (sEMG), two force plates and a motion capture system. All signals were synchronized in time with the gait cycle. The sEMG activity of Rectus Femoris (RF), Tibialis Anterior (TA), Biceps Femoris (BF) and Gastrocnemius Lateralis (GL) were acquired. The average from each signal was used to extract the peak of the Envelope (PoE) and its occurrence with respect to the gait cycle (PoPE%). Time and space parameters were determined.ResultsOur results showed that UT in PD patients improved the muscle’s recruitment pattern towards normal. The PD patients POPE% was comparable with the one of the controls (TA: 20–35 %, 75–80 % of gait cycle; GL: 0–15 %, 25–45 %, 85–100 % of gait cycle) after UT on each muscle with the exception of BF. The muscle co-activation plots failed to show improvement in line with the muscle activation.SignificanceThese results suggest that the muscle activation improvement with UT in PD participants might be due to a reorganisation at the executive rather than at the command level.     

Upper body accelerations as a biomarker of gait impairment in the early stages of Parkinson’s disease

BackgroundChanges in upper body (UB) motion during gait may be a marker of incipient pathology, intervention response and disease progression in Parkinson’s disease (PD), which if independent from the lower body motion, might provide an improved assessment of gait.Research questionThis study aimed to test this hypothesis and establish whether variables calculated from accelerations measured on the UB are unique from spatiotemporal characteristics and can contribute to an improved classification of PD gait.MethodsData was obtained from 70 people with PD (69.2 ± 9.9 y.o., UPDRS III: 36.9 ± 12.3) and 64 age-matched controls (71.6 ± 6.8 y.o.). Spatiotemporal characteristics were measured using a pressure sensitive mat (GAITRite). Head and pelvis accelerations were synchronously measured with wearable inertial sensors (Opal, APDM). Pearson’s product-moment correlations were calculated between 49 selected variables from UB accelerations (representing magnitude, smoothness, regularity, symmetry and attenuation) and 16 traditional spatiotemporal characteristics (representing pace, variability, rhythm, asymmetry and postural control). Univariate and multivariate regression analysis was used to test the variables ability to classify PD gait.ResultsThe variables were mostly unique from each other (67% of variables recorded an r < 0.3). Univariate and multivariate analysis showed that UB variables were moderately better at classifying PD gait than the spatiotemporal characteristics (Univariate: 0.70 to 0.81, Multivariate: 0.88 to 0.91 AUC).SignificanceThis study showed for the first time that, if aiming at objective and optimal sensitive biomarkers for PD, UB variables should be measured in conjunction with spatiotemporal characteristics to obtain a more holistic assessment of PD gait for use in a clinical or free-living environment.     

Usefulness of rCBF analysis in diagnosing Parkinson’s disease: supplemental role with MIBG myocardial scintigraphy

(123)I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy is a useful tool for differentiating idiopathic Parkinson's disease (PD) from parkinsonism (PS) caused by other disorders. However, cardiac MIBG uptake is affected by various causes. Alternatively, hypoperfusion in the occipital lobe of PD is reported recently. OBJECTIVE: The objective is to clarify the correlation between regional cerebral blood flow (rCBF) alteration and cardiac MIBG uptake in PD. In addition, we examined whether additional brain perfusion analysis improved the differential diagnostic ability for PD from PS when compared with MIBG scintigraphy alone. METHODS: Forty-nine patients with PD (27 mild groups: Hoehn and Yahr stages I, II; 22 severe groups: Hoehn and Yahr stages III, IV) and 28 patients with PS participated. We compared absolute rCBF values between PD and PS. In addition, we determined correlation between MIBG parameters and each rCBF value. Finally, we compared the diagnostic ability for the differentiation of PD from PS between two diagnostic criteria, each MIBG index abnormality alone [heart-to-mediastinum ratio, H/M (E) < 1.9, H/E (D) < 1.7, washout rate > 40%] and each MIBG index abnormality or occipital lobe hypoperfusion (<36 ml/100 g per min). RESULTS: Absolute rCBF value of occipital lobe was significantly lower in severe PD as compared with PS or mild PD. In the correlation analysis, rCBF of occipital lobe correlated positively with MIBG parameters (H/M). Regarding the diagnostic ability, sensitivity improved by accounting for occipital hypoperfusion as compared with MIBG indices alone. In contrast, neither specificity nor accuracy improved by adding occipital lobe analysis. CONCLUSIONS: MIBG parameters (H/M) correlated positively with occipital hypoperfusion in PD. In the differential diagnosis between PD and PS, although its usefulness might be limited, analysis of rCBF in the occipital lobe added to (123)I-MIBG myocardial imaging can be recommended.     

A new approach toward gait training in patients with Parkinson’s Disease

BackgroundTypically, people with Parkinson’s Disease (PD) progress to develop a gait pattern that is characterized by quick, short and shuffling steps. Gait cycle is altered and lacks definition and fluidity. Gait training combined with a variety of feedback modalities for PD are usually based on non-immediate and externally-based cues but none of these provide real-time feedback on gait quality and acquired gains tend to abate shortly after rehabilitation. Based on principals of motor learning, our team has developed the Heel2Toe sensor to provide real-time auditory feedback during gait training.Research questionIs a short-term training using the Heel2Toe sensor feasible and efficient to improve gait in people with PD? Our objectives are to identify the extent of the immediate response to the feedback within the same session and the carry-over response to training and; 2) to identify patients’ perceived effects, pleasures and challenges of using the Heel2Toe.MethodsSingle-arm, proof-of-concept study. Six people received five sessions of gait training over a 2–3-week period using the Heel2Toe augmented with mobility exercises as an adjunct to gait training. The main outcomes were technically assessed gait parameters collected over a 2-minute walk test, without and with feedback. Heel2Toe signals were analyzed to extract angular velocity(AV), percentage of good steps, average cadence, and AV coefficient of variation(CV).ResultsAn immediate response to the Heel2Toe use and a carry-over response to the short-term training with the sensor were observed: an increase in AV with a reduction in CV (better heel strike and gait regularity); an increase in %good steps; and a near-optimal and homogeneous cadence (∼100 steps/min), which is equivalent to a moderate-intensity walking.SignificanceGait training using the Heel2Toe sensor is feasible and potentially effective for improving gait quality in people with PD. A definitive trial is a logical next step.     

Objective measures to investigate turning impairments and freezing of gait in people with Parkinson’s disease

BackgroundTurning is impaired in people with Parkinson’s Disease (PD) and it is a common trigger for freezing of gait (FoG). Recent evidence suggests that people with PD who freeze (PD+FoG) have worse turning performance than those who don’t have freezing (non-freezers, PD-FoG), and the freezing episodes are exacerbated by increasing the turn angular amplitude.Research questionWe investigated the difference between turning 180° while walking versus turning 360° in place, in both single- and dual-task conditions, by means of objective measures in people with PD with and without FoG.MethodsTwenty-four PD+FoG and eighteen PD-FoG performed 180° turns while walking and 360° turns in place during single- and dual-task conditions. Quantitative measures of turning and the dual-task cost were computed. Differences were investigated between groups and within turning types using ANOVA. Associations between turn measures and clinical scales were examined with Spearman correlations.ResultsTurn duration and the number of steps were greater, and peak angular velocity slower, in PD+FoG compared to PD-FoG (p < 0.001). Dual-task costs were similar across groups, but turn duration showed significant interaction (p = 0.03). Posture Instability and Gait Disability (PIGD) subscore was associated with all turn measures in PD-FoG; whereas PIGD was mainly associated with turning while walking in PD+FoG.SignificanceObjective measures of turning revealed differences between people with and without FoG, specifically, people with FoG showed more impairments in 360° turning in place compared to 180° turning while walking. However, as the turning challenges were increased by adding a dual-task, results from PD+FoG were similar to those from PD-FoG.