Modulation of anticipatory postural adjustments using a powered ankle orthosis in people with Parkinson's disease and freezing of gait

Application of robotic lower limb orthosis for people with lower limb dysfunction

Due to the aging of the population or diseases, the number of patients with lower limb disorders has increased, causing social concern. Scholars have designed and developed advanced robotic lower limb orthoses, which can guide patients to perform reasonable rehabilitation training with correct limb postures, enhance their daily life participation and quality of life, and help them recover quickly. In recent years, a large number of new and advanced orthopedic equipment have been developed, which require a systematic summary analysis and comparison. This article reviewed typical newly developed, robotic lower limb orthoses and their use effects, as well as the advanced theories and technologies for their applications, and systematically discussed the problems in the research, design, testing, use, and popularization of robotic lower limb orthoses, and predicted their development direction in the future research and design, to enhance the reliability, convenience, and protection functions of orthotic equipment, make its functions closer to life, and give full play to the initiative of patients in the process of rehabilitation training, and reduce costs. Robotic lower limb orthoses is poised for even greater success and development in the future.

Recent advances in wearable actuated ankle-foot orthoses: Medical effects, design, and control

This paper presents a survey on recent advances of wearable actuated ankle-foot orthoses (AAFOs). First of all, their medical functions are investigated. From the short-term aspect, they lead to rectification of pathological gaits, reduction of metabolic cost, and improvement of gait performance. After AAFO-based walking training with sufficient time, free walking performance can be enhanced. Then, key design factors are studied. First, primary design parameters are investigated. Second, common actuators are analysed. Third, human-robot interaction (HRI), ergonomics, safety, and application places, are considered. In the following section, control technologies are reviewed from the aspects of rehabilitation stages, gait feature quantities, and controller characteristics. Finally, existing problems are discussed; development trends are prospected.

Life-space mobility, balance and self-efficacy in Parkinson's disease: a cross-sectional study

OBJECTIVE

Life-space mobility (LSM) is a mobility measure that assesses the physical and social environments through which people move during their daily lives. To characterize LSM among individuals with Parkinson's disease and explore the relationship between LSM, self-efficacy, and balance.

DESIGN

A cross-sectional study.

SETTINGS

Movement disorder clinic at a teaching hospital.

PARTICIPANTS

Eighty-eight participants with Parkinson's disease.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The dependent variable (LSM) was assessed using the Life-Space Assessment (LSA) instrument. Balance evaluation and balance self-efficacy were assessed using the Mini Balance Evaluation Systems Test (Mini-BESTest) and the Activities-Specific Balance Confidence Scale, respectively. Other variables, such as age, disease staging (Hoehn-Yahr staging system), cognition (Montreal Cognitive Assessment), and depressive symptoms (Beck Depression Inventory-II), were also measured.

RESULTS

The mean LSA score was 65.22 (SD [SD]: 22.75) and mean age was 66.99 years (SD: 9.35 years). Among the 88 patients, 35 (39.7%) were classified as restricted SM. Age (P = 0.03), disease severity (P = 0.02), cognition (P = 0.02), and motor subtype (P = 0.006) were associated with more restricted LSM among participants. A multiple linear regression model demonstrated that LSM can be predicted by balance performance (R²  = 0.377; P < 0.001).

CONCLUSIONS

Age, disease severity, cognition, motor subtype, balance self-efficacy, and balance performance are associated with LSM. Understanding and improving balance and self-efficacy in people with Parkinson's disease could facilitate community mobility and promote functional independence and health maintenance. This article is protected by copyright. All rights reserved.

Can People with Parkinson's Disease Self-Trigger Gait Initiation? A Comparison of Cueing Strategies

BACKGROUND

An external cue can markedly improve gait initiation in people with Parkinson's disease (PD) and is often used to overcome freezing of gait (FOG). It is unknown if the effects of external cueing are comparable if the imperative stimulus is triggered by the person receiving the cue (self-triggered) or an external source.

OBJECTIVE

Two experiments were conducted to compare the effects of self- versus externally triggered cueing on anticipatory postural adjustments (APAs) during gait initiation in people with PD.

METHODS

In experiment 1, 10 individuals with PD and FOG initiated gait without a cue or in response to a stimulus triggered by the experimenter or by the participant. Experiment 2 compared self- versus externally triggered cueing across three groups: healthy young adults (n = 16), healthy older adults (n = 11), and a group with PD (n = 10).

RESULTS

Experiment 1: Externally triggered cues significantly increased APA magnitudes compared to uncued stepping, but not when the same cue was self-triggered. Experiment 2: APAs were not significantly improved with a self-triggered cue compared to un-cued stepping in both the PD and healthy older adult groups, but the young adults showed a significant facilitation of APA magnitude.

CONCLUSION

The effectiveness of an external cue on gait initiation in people with PD and older adults is critically dependent upon whether the source of the trigger is endogenous (self-produced) or exogenous (externally-generated). These results may explain why cueing interventions that rely upon self-triggering of the stimulus are often ineffective in people with PD.

In Patients With Parkinson's Disease in an OFF-Medication State, Does Bilateral Electrostimulation of Tibialis Anterior Improve Anticipatory Postural Adjustments During Gait Initiation?

A complete lack of bilateral activation of tibialis anterior (TA) during gait initiation (GI), along with bradykinetic anticipatory postural adjustments (APAs), often occurs in patients with Parkinson's disease (PD) in their OFF-medication state. Functional electrical stimulation (FES) is a non-pharmacological method frequently used in neurorehabilitation to optimize the effect of L-DOPA on locomotor function in this population. The present study tested the potential of bilateral application of FES on TA to improve GI in PD patients. Fourteen PD patients (OFF-medication state, Hoehn and Yahr state 2-3) participated in this study. They performed series of 10 GI trials on a force-plate under the following experimental conditions: (1) GI without FES (control group), (2) GI with 2Hz-FES (considered as a very low FES frequency condition without biomechanical effect; placebo group) and (3) GI with 40Hz-FES (test group). In (2) and (3), FES was applied bilaterally to the TA during APAs (300 mA intensity/300 μs pulse width). Main results showed that the peak of anticipatory backward center of pressure shift, the forward center of mass (COM) velocity and shift at foot off were significantly larger in the 40 Hz FES condition than in the control condition, while the duration of step execution was significantly shorter. In contrast, the capacity of participants to brake the fall of their COM remained unchanged across conditions. Globally taken, these results suggest that acute application of 40-Hz FES to the TA may improve the capacity of PD patients to generate APAs during GI, without altering their balance capacity. Future studies are required before considering that TA FES application might be a valuable tool to improve GI in PD patients and be relevant to optimize the effects of L-DOPA medication on locomotor function.

Prevalence of freezing of gait in Parkinson's disease: a systematic review and meta-analysis

BACKGROUND

Freezing of gait (FOG) is considered one of the most disturbing and least understood symptoms in Parkinson's disease (PD). The reported prevalence rates of FOG in PD vary widely, ranging from 5 to 85.9%.

OBJECTIVE

We conducted a systematic review and meta-analysis to provide a reliable estimate of the average point prevalence of FOG in PD, and we further investigated the study characteristics that might have influenced the estimate.

METHODS

We searched different databases to identify studies that report the prevalence of FOG in PD or include relevant raw data for further calculation. The last inclusion date was February 20, 2020. The modified Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool was used for the quality assessment, and articles that met the predefined criteria were included in the quantitative analysis.

RESULTS

Sixty-six studies were selected from 3392 references. A weighted prevalence of 50.6% in 9072 PD patients experienced FOG based on the special questionnaires (the FOG-Q and NFOG-Q), which was about twice as high as that assessed by the specific items of the clinical rating scales (UPDRS item2.14 and MDS-UPDRS item3.11) (23.2%) or simple clinical questions (25.4%). The weighted prevalence was 37.9% for early stage (≤ 5 years) and 64.6% for advanced stage (≥ 9 years). Moreover, a higher prevalence was calculated from the population-based studies than that in multicenter and single-center studies (47.3% vs. 33.5% and 37.1%, respectively).

CONCLUSION

The result from this systematic review confirms that FOG is very common in PD and its prevalence is usually underestimated in hospital settings. Importantly, a more accurate assessment of FOG in future clinical researches would involve the use of special FOG scale rather than a single item on a scale or a general clinical inquiry.

Severity Classification of Parkinson’s Disease Based on Permutation-Variable Importance and Persistent Entropy

Parkinson’s disease (PD) is a neurodegenerative disease that causes chronic and progressive motor dysfunction. As PD progresses, patients show different symptoms at different stages of the disease. The severity assessment is inefficient and subjective when it comes to artificial diagnosis. However, abnormal gait was contingent and the subject selection was limited. Therefore, few-shot learning based on small sample sets is critical to solving the problem of insufficient sample data in PD patients. Using datasets from PhysioNet, this paper presents a method based on permutation-variable importance (PVI) and persistent entropy of topological imprints, and uses support vector machine (SVM) as a classifier to achieve the severity classification of PD patients. The method includes the following steps: (1) Take the data as gait cycles, and calculate the gait characteristics of each cycle. (2) Use the random forest (RF) method to obtain the leading factors differentiating the gait of patients at different severity levels. (3) Use time-delay embedding to map the data into a topological space, and use the topological data analysis based on permutation homology to obtain the persistent entropy. (4) Use the Borderline-SMOTE (BSM) method to balance the sample data. (5) Use the SVM to classify the samples for the severity levels of PD. An accuracy of 98.08% was achieved by 10-fold cross-validation, so our method can be used as an effective means of computer-aided diagnosis of PD, and has important practical value.

Impact of Footwear and Foot Deformities in patients with Parkinson's disease: A Case-Series Study

Background: Parkinson's disease (PD) is a common and complex neurological problem. Gait abnormalities are frequent in PD patients, and this increases the risk of falls. However, little is known about foot deformities and footwear in this vulnerable population. Here we investigate whether patients with PD use an appropriate shoe size and know if they have foot deformities or alterations. Methodology: A study of a series of observational descriptive cases in a convenience sample (n = 53 patients) diagnosed with Parkinson's disease. One trained investigator evaluated foot and ankle health. The footwear and foot measurements were obtained using a Brannock device. Results: The podiatric examination and footwear examination detected a high presence of podiatric pathologies and inappropriate footwear. This has a negative impact on the quality of life of these patients. Conclusions: This research detected an elevated number of people with foot deformities or alterations. Moreover, a high proportion of participants with PD wear inadequate footwear (in length, width, or both).