Functional limits of stability and standing balance in people with Parkinson's disease with and without freezing of gait using wearable sensors

Does Impaired Plantar Cutaneous Vibration Perception Contribute to Axial Motor Symptoms in Parkinson's Disease? Effects of Medication and Subthalamic Nucleus Deep Brain Stimulation

OBJECTIVE

To investigate whether impaired plantar cutaneous vibration perception contributes to axial motor symptoms in Parkinson's disease (PD) and whether anti-parkinsonian medication and subthalamic nucleus deep brain stimulation (STN-DBS) show different effects.

METHODS

Three groups were evaluated: PD patients in the medication "on" state (PD-MED), PD patients in the medication "on" state and additionally "on" STN-DBS (PD-MED-DBS), as well as healthy subjects (HS) as reference. Motor performance was analyzed using a pressure distribution platform. Plantar cutaneous vibration perception thresholds (VPT) were investigated using a customized vibration exciter at 30 Hz.

RESULTS

Motor performance of PD-MED and PD-MED-DBS was characterized by greater postural sway, smaller limits of stability ranges, and slower gait due to shorter strides, fewer steps per minute, and broader stride widths compared to HS. Comparing patient groups, PD-MED-DBS showed better overall motor performance than PD-MED, particularly for the functional limits of stability and gait. VPTs were significantly higher for PD-MED compared to those of HS, which suggests impaired plantar cutaneous vibration perception in PD. However, PD-MED-DBS showed less impaired cutaneous vibration perception than PD-MED.

CONCLUSIONS

PD patients suffer from poor motor performance compared to healthy subjects. Anti-parkinsonian medication in tandem with STN-DBS seems to be superior for normalizing axial motor symptoms compared to medication alone. Plantar cutaneous vibration perception is impaired in PD patients, whereas anti-parkinsonian medication together with STN-DBS is superior for normalizing tactile cutaneous perception compared to medication alone. Consequently, based on our results and the findings of the literature, impaired plantar cutaneous vibration perception might contribute to axial motor symptoms in PD.

Clinical Static Balance Assessment: A Narrative Review of Traditional and IMU-Based Posturography in Older Adults and Individuals with Incomplete Spinal Cord Injury

Maintaining a stable upright posture is essential for performing activities of daily living, and impaired standing balance may impact an individual's quality of life. Therefore, accurate and sensitive methods for assessing static balance are crucial for identifying balance impairments, understanding the underlying mechanisms of the balance deficiencies, and developing targeted interventions to improve standing balance and prevent falls. This review paper first explores the methods to quantify standing balance. Then, it reviews traditional posturography and recent advancements in using wearable inertial measurement units (IMUs) to assess static balance in two populations: older adults and those with incomplete spinal cord injury (iSCI). The inclusion of these two groups is supported by their large representation among individuals with balance impairments. Also, each group exhibits distinct aspects in balance assessment due to diverse underlying causes associated with aging and neurological impairment. Given the high vulnerability of both demographics to balance impairments and falls, the significance of targeted interventions to improve standing balance and mitigate fall risk becomes apparent. Overall, this review highlights the importance of static balance assessment and the potential of emerging methods and technologies to improve our understanding of postural control in different populations.

Exploring mobility dysfunction in people with and without impaired cognition in Parkinson disease

INTRODUCTION

The relationship between mobility and cognition has been studied in the aging population and associations have been also reported in people with Parkinson's disease (PD).

OBJECTIVE

To compare different aspects of gait and balance between individuals with PD who have normal cognition and those with impaired cognition, using both clinical and instrumented measures.

METHODS

One-hundred forty-three participants with PD were divided into two groups: 1) normal cognition (n = 71) and 2) impaired cognition (n = 72) based on the Montreal Cognitive Assessment (MoCA) cut-off. Groups were compared using instrumented and clinical measures of gait and balance in the following domains: Sensory Orientation, Anticipatory Postural Adjustments, Automatic Postural Responses and Dynamic Balance for Gait. Instrumented measures were obtained via wearable sensors while performing eight different motor tasks and clinical measures were obtained with the Mini-BESTest.

RESULTS

The total Mini-BESTest score was not different between groups. However, the Dynamic Gait domain was worse in individuals with impaired cognition. Among the instrumented measures across domains, all significant group differences were in the Dynamic Gait domain, specifically, dual-task gait speed, dual-task stride length, stance time, and turn velocity.

CONCLUSIONS

Dynamic balance during gait was more impaired in people with PD who had abnormal cognition than those with normal cognition, for both clinical and instrumented measures. All other balance domains did not differ between groups, for both instrumented and clinical measures.

Accelerometry applications and methods to assess standing balance in older adults and mobility-limited patient populations: a narrative review

Accelerometers provide an opportunity to expand standing balance assessments outside of the laboratory. The purpose of this narrative review is to show that accelerometers are accurate, objective, and accessible tools for balance assessment. Accelerometry has been validated against current gold standard technology, such as optical motion capture systems and force plates. Many studies have been conducted to show how accelerometers can be useful for clinical examinations. Recent studies have begun to apply classification algorithms to accelerometry balance measures to discriminate populations at risk for falls. In addition to healthy older adults, accelerometry can monitor balance in patient populations such as Parkinson's disease, multiple sclerosis, and traumatic brain injury. The lack of software packages or easy-to-use applications have hindered the shift into the clinical space. Lack of consensus on outcome metrics has also slowed the clinical adoption of accelerometer-based balance assessments. Future studies should focus on metrics that are most helpful to evaluate balance in specific populations and protocols that are clinically efficacious.

Sex differences in age-related differences in joint motion during gait in community-dwelling middle-age and older individuals

BACKGROUND

Walking is the most important mode of human locomotion; however, the ability to walk often decreases with age. Age-related differences in lower-limb kinematics during gait may differ depending on sex. However, the question of the compounded effects of age and sex on gait kinematics remains unsolved.

RESEARCH QUESTION

The present study aimed to clarify the interaction between age and sex in differences in gait kinematics of community-dwelling middle-age and older individuals.

METHODS

This study included 836 community-dwelling middle-age and older adults (61.8 % female). Joint motion during comfortable gait was measured using magnetic and inertial measurement units. Hip, knee, and ankle joint angles were calculated in the sagittal plane. Participants were divided into four groups according to age: 50-59, 60-69, 70-79, and 80-89 years. The interaction of sex and age on spatiotemporal gait parameters and the peak value of joint angles was analyzed using two-way analysis of variance (ANOVA) and Tukey's post hoc test.

RESULTS

Gait speed (F = 43.92, P < 0.001), step length (F = 73.00, P < 0.001), hip extension (F = 12.89, P = 0.002), knee flexion (F = 39.99, P < 0.001), and ankle plantar flexion (F = 27.43, P < 0.001) significantly decreased with age. Significant differences according to sex were observed in all parameters except gait speed. Significant age and sex interaction effects were observed for knee flexion (F = 4.97, P = 0.002) and ankle dorsiflexion (F = 4.04, P = 0.007).

SIGNIFICANCE

A significant interaction effect of age and sex was observed for peak angle of knee flexion and ankle dorsiflexion during gait. In particular, the knee flexion angle among females during gait began to decrease from 60 years of age, and the decreasing trend was faster and more prominent than that among males.

Effects of freezing of gait on balance in patients with Parkinson's disease

OBJECTIVES

The aim of the study was to evaluate the effects of freezing of gait (FOG) on static and dynamic balance.

METHODS

Twenty patients with Parkinson's disease with and without FOG [PD+FOG (68,6±6,39 years) and PD-FOG group (70,6±4,57 years)] and 10 healthy individuals (68,4±4,92 years) with similar demographic characteristics were included in the study. Balance was compared between the three groups. Balance was evaluated with clinical tests Limits of stability (LoS) and body sway were measured using the E-LINK FP3 Force Plate and the Korebalance Balance Evaluation System, which measure the balance in static and dynamic conditions. Center of pressure (COP) change and average sway velocity were evaluated with the Zebris RehaWalk system.

RESULTS

Total and subscale scores of the Unified Parkinson's Disease Rating Scale were significantly higher in the PD+FOG group (p<0.05). The balance test results for both groups were similar (p>0.05). The PD+FOG group performed worse on the computerized static balance tests, the COP analysis, and the dynamic balance total score than the other two groups (p<0.05). The PD+FOG group had significantly greater sustained weight deviation than the healthy controls (p<0.05). Patients with Parkinson's disease had a lower LoS in the posterior direction than healthy controls (p<0.05).

DISCUSSION

FOG affects the dynamic balance more negatively than the static balance. In addition, FOG reduces LoS in the posterior direction and increases body sway in the anterior-posterior direction, which can lead to falls.

Real-time detection of freezing of gait in Parkinson's disease using multi-head convolutional neural networks and a single inertial sensor

BACKGROUND

Freezing of gait (FOG) is one of the most disabling symptoms of Parkinson's disease (PD), contributing to poor quality of life and increased risk of falls. Wearable sensors represent a valuable means for detecting FOG in the home environment. Moreover, real-time feedback has proven to help reduce the duration of FOG episodes. This work proposes a robust real-time FOG detection algorithm, which is easy to implement in stand-alone devices working in non-supervised conditions.

METHOD

Data from three different data sets were used in this study, with two employed as independent test sets. Acceleration recordings from 118 PD patients and 21 healthy elderly subjects were collected while they performed simulated daily living activities. A single inertial sensor was attached to the waist of each subject. More than 17 h of valid data and a total number of 1110 FOG episodes were analyzed in this study. The implemented algorithm consisted of a multi-head convolutional neural network, which exploited different spatial resolutions in the analysis of inertial data. The architecture and the model parameters were designed to provide optimal performance while reducing computational complexity and testing time.

RESULTS

The developed algorithm demonstrated good to excellent classification performance, with more than 50% (30%) of FOG episodes predicted on average 3.1 s (1.3 s) before the actual onset in the main (independent) data set. Around 50% of FOG was detected with an average delay of 0.8 s (1.1 s) in the main (independent) data set. Moreover, a specificity above 88% (93%) was obtained when testing the algorithm on the main (independent) test set, while 100% specificity was obtained on healthy elderly subjects.

CONCLUSION

The algorithm proved robust, with low computational complexity and processing time, thus paving the way to a real-time implementation in a stand-alone device that can be used in non-supervised environments.

The Effect of Non-Immersive Virtual Reality Exergames versus Traditional Physiotherapy in Parkinson's Disease Older Patients: Preliminary Results from a Randomized-Controlled Trial

(1) Background: Parkinson's disease (PD) is one of the most frequent causes of disability among older people. Recently, virtual reality and exergaming have been emerged as promising tools for gait and balance rehabilitation in PD patients. Our purpose is to evaluate an innovative treatment for older patients with PD, based on non-immersive virtual reality exergames, improving gait and balance and reducing falling risk. (2) Methods: Thirty PD patients were recruited and randomly divided into two groups, to receive a traditional rehabilitation (CG) or a technological rehabilitation (TG). (3) Results: A statistical improvement of balance at the end of treatments was observed in both groups (CG: 12.4 ± 0.7 vs. 13.5 ± 0.8, p = 0.017; TG: 13.8 ± 0.5 vs. 14.7 ± 0.4, p = 0.004), while the overall risk of falling was significantly reduced only in the TG (POMA Total: 24.6 ± 0.9 vs. 25.9 ± 0.7, p = 0.010). The results between groups shows that all POMA scores differ in a statistically significant manner in the TG, emphasizing improvement not only in balance but also in gait characteristics (9.7 ± 0.8 vs. 11.4 ± 0.2, p = 0.003). Moreover, TG also improves the psychological sphere, measured thorough MSC-(17.1 ± 0.4 vs. 16.5 ± 0.4, p = 0.034). Although an improvement in FES-I and Gait Speed can be observed, this increase does not turn out to be significant. (4) Conclusions: Results suggest how non-immersive virtual reality exergaming technology offers the opportunity to effectively train cognitive and physical domains at the same time.