Gait Initiation Impairment in Patients with Parkinson's Disease and Freezing of Gait

Gait initiation deficits in Parkinson's disease with freezing of gait: A large-scale force platform study of anticipatory postural adjustments

INTRODUCTION

Freezing of gait (FoG) is a debilitating motor symptom in Parkinson's disease (PD), often occurring during step initiation due to impaired anticipatory postural adjustments (APAs). Previous studies show inconsistent findings regarding APA alterations in people with PD with FoG (PwPD + FoG) and without FoG (PwPD-FoG). This study aimed to investigate APA characteristics using a force platform to assess postural control deficits associated with FoG.

METHODS

We analyzed baseline data from 130 PwPD (70 with FoG) and 41 healthy controls. A force platform during self-initiated stepping measured APA duration, amplitude, and step amplitude. All participants with PD were tested in the ON medication. One-way ANOVA and ANCOVA (controlling for UPDRS-III and medication) were conducted to compare groups.

RESULTS

APA duration was significantly shorter in Healthy compared to PwPD + FoG and PwPD-FoG, with no difference between PD groups. Step amplitude was significantly lower in PwPD + FoG compared to Healthy and PwPD-FoG, but this difference was insignificant after covariate. APA mediolateral amplitude followed PD + FoG < PD-FoG < Healthy; ANCOVA confirmed lower values in PwPD + FoG compared to PwPD-FoG. APA anteroposterior amplitude was also reduced in PwPD + FoG relative to PwPD-FoG and Healthy, with ANCOVA confirming significantly lower values in PwPD + FoG versus PwPD-FoG. NFOG-Q scores were negatively correlated with mediolateral and anteroposterior APA amplitudes.

CONCLUSION

FoG in PD is associated with reduced APA amplitude (mediolateral and anteroposterior), suggesting postural control deficits persist despite dopaminergic medication. These findings highlight the importance of interventions targeting APA improvements to mitigate gait initiation failures in PwPD + FoG.

Phenotyping the demographic and behavioral correlates of start hesitation in Parkinson's disease

INTRODUCTION

Freezing of gait (FOG) is a significant symptom in Parkinson's Disease (PD) that has been associated with attentional set shifting deficits, suggesting an underlying frontostriatal neurobiology. Whilst to date Start Hesitation (SH) has been regarded as a subtype of FOG, whether it shares the same underlying neural correlates remains unknown. The specific correlation of SH with other clinical features might help to elucidate its neurobiological underpinnings, which could potentially offer novel treatment strategies.

METHODS

In this study, 72 PD patients underwent a previously validated VR gait paradigm in either On, Off or both medication states to identify episodes of SH. Participants also underwent a standardized clinical battery covering motor and non-motor features, including neuropsychometric testing across domains of attention, language, working memory, and visuospatial function.

RESULTS

The presence of SH was identified in 48 of the 72 patients. Compared to patients without SH, those demonstrating SH had a significantly higher depression score (3.8 vs 2.2, p = 0.045) and reported more REM Sleep Behavior Disorder (5.8 vs 3.3, p = 0.005). Notably, there were no significant group differences in age, disease duration, MDS-UPDRS scores, motor phenotype, falls risk, or any cognitive domains. In those patients with SH, there were no correlations of large magnitude between the duration of SH episodes and any relevant clinical, demographic or neuropsychometric measures.

CONCLUSION

These results suggest that the neurobiological underpinnings of SH are distinct from those reported across FOG and may relate more to brainstem pathology. Further neuroimaging and neurophysiological approaches are now required.

Management of freezing of gait - mechanism-based practical recommendations

Freezing of gait (FOG) is a debilitating motor symptom that commonly occurs in Parkinson disease, atypical parkinsonism and other neurodegenerative conditions. Management of FOG is complex and requires a multifaceted approach that includes pharmacological, surgical and non-pharmacological interventions. In this Expert Recommendation, we provide state-of-the-art practical recommendations for the management of FOG, based on the latest insights into the pathophysiology of the condition. We propose two complementary treatment flows, both of which are linked to the pathophysiology and tailored to specific FOG phenotypes. The first workflow focuses on the reduction of excessive inhibitory outflow from the basal ganglia through use of dopaminergic medication or advanced therapies such as deep brain stimulation and infusion therapy. The second workflow focuses on facilitation of processing across cerebral compensatory networks by use of non-pharmacological interventions. We also highlight interventions that have potential for FOG but are not supported by sufficient evidence to recommend for clinical application. Our updated recommendations are intended to enable effective symptomatic relief once FOG has developed, but we also consider potential targets for preventive approaches. The recommendations are based on scientific evidence where available, supplemented with practice-based evidence informed by our clinical experience.

Color-induced cognitive conflicts affect muscle activity prior to gait initiation in the Go/No-go task

Introduction

In traffic rule, green/blue means go, and red means stop. It has been shown that this prior knowledge about traffic signal colors can affect reaction times (RTs). For example, RTs are longer when responding to a red "Go" signal and withholding the response to a blue "No-go" signal (Red Go/Blue No-go task) than when responding to a blue "Go" signal and withholding the response to a red "No-go" signal (Blue Go/Red No-go task), when responses are provided by button press. However, it remains unknown whether this holds in different actions. The aim of this study was to investigate the effect of prior knowledge of color on gait initiation in a Go/No-go task.

Methods

Seventeen participants performed Green Go/Red No-go and Red Go/Green No-go tasks, in which they stepped forward from a force plate in response to a green or red signal and withhold the response to red or green signal, respectively. We recorded the center of pressure (COP) and electromyogram (EMG) from the bilateral tibialis anterior muscles during gait initiation.

Results

The onset of COP movement and toe-off time as well as COP displacements did not differ between the Go/No-go tasks. The EMG onset for the stance leg was delayed in the Red Go/Green No-go than Green Go/Red No-go task.

Discussion

These findings suggest that the conflict between prior knowledge of color related to traffic rule and the meaning of the stimulus color affects muscle activity but not COP characteristics during gait initiation, highlighting two distinct motor control mechanisms, where the initial phase is influenced by cognitive load while the subsequent phase remains unaffected. This dissociation suggests that the later phase of gait initiation relies on robust spinal loops and central pattern generators, which are less influenced by cognitive factors such as prior knowledge.

Identifying the content of the Lower Extremity Motor Activity Log based on the International Classification of Functioning, Disability and Health

PURPOSE

To identify the content and the constructs measured in the Lower Extremity Motor Activity Log (LE-MAL) based on the International Classification of Functioning, Disability and Health (ICF) framework and to determine whether the instrument items fit within the ICF mobility domain.

METHODS

Concepts and constructs measured within each scale were linked to the best-matched ICF categories and classified using established linking rules. Two independent researchers determined the initial linkages. A final consensus was reached with the other researchers. The agreement was analysed through the agreement percentage and the kappa coefficient.

RESULTS

The subscales assess performance through information about need or dependency, personal and environmental factors, and appraisal of the items. Thirteen concepts were identified in LE-MAL: two concepts for the Assistance Scale are covered in the environmental factors component; 10 concepts for the Functional Performance Scale where all items are covered in the mobility domain; one concept for the confidence scale is covered in the body functions component.

CONCLUSIONS

The general construct of LE-MAL assessed is performance in the ICF mobility domain and provides additional information about the mental function, environmental factors, independence, appraisal, and personal factors. The study highlighted the conceptual connection between the LE-MAL and the ICF framework.

Case report: Improvement of gait with adaptive deep brain stimulation in a patient with Parkinson's disease

Gait disturbance is a common and severe symptom of Parkinson's disease that severely impairs quality of life. Current treatments provide only partial benefits with wide variability in outcomes. Also, deep brain stimulation of the subthalamic nucleus (STN-DBS), a mainstay treatment for bradykinetic-rigid symptoms and parkinsonian tremor, is poorly effective on gait. We applied a novel DBS paradigm, adjusting the current amplitude linearly with respect to subthalamic beta power (adaptive DBS), in one parkinsonian patient with gait impairment and chronically stimulated with conventional DBS. We studied the kinematics of gait and gait initiation (anticipatory postural adjustments) as well as subthalamic beta oscillations with both conventional and adaptive DBS. With adaptive DBS, the patient showed a consistent and long-lasting improvement in walking while retaining benefits on other disease-related symptoms. We suggest that adaptive DBS can benefit gait in Parkinson's disease possibly by avoiding overstimulation and dysfunctional entrainment of the supraspinal locomotor network.

Dynamic evaluation of spine kinematics in individuals with Parkinson's disease and freezing of gait

BACKGROUND

Freezing of gait (FoG) is an episodic failure of gait exposing people with Parkinson's disease (PD) to a high risk of falling. Despite growing evidence of the interconnection between impaired trunk control and FoG, a detailed description of spinal kinematics during walking is still lacking in this population.

RESEARCH QUESTION

Do spinal alterations impact gait performance in individuals with PD and FoG?

METHODS

We analyzed kinematic data of 47 PD participants suffering (PD-FOG, N = 24) or not suffering from FoG (PD-NFOG, N = 23) and 15 healthy controls (HCO) during quiet standing and unperturbed walking. We estimated the main spinal variables (i.e., spinal length, lordosis and kyphosis angles, trunk inclination), the pelvis angles, and the shoulder-pelvis angles during gait and standing. We studied differences across conditions and groups and the relationships between postural and gait parameters using linear regression methods.

RESULTS

During standing and walking, both PD groups showed increased trunk inclination and decreased lordosis angle with respect to HCO, as well as a decreased range in variation of kyphosis angle, pelvic obliquity, and shoulder-pelvis angles. Only PD-FOG participants showed reduced range of lordosis angle and spinal length compared to HCO. PD-FOG individuals were also not able to straighten their spine during walking compared to standing. Stride length and velocity were decreased in both patient groups compared to HCO, while swing duration was reduced only in the PD-FOG group. In individuals with FoG, trunk inclination and lordosis angle showed moderate but significant positive correlations with all gait alterations.

SIGNIFICANCE

Spine alterations impacted gait performance in individuals with PD suffering from FoG. Excessive trunk inclination and poor mastering of the lordosis spinal region may create an unfavourable postural precondition for forward walking. Physical therapy should target combined spinal and stepping alterations in these individuals.

Correlation of balance posturographic parameters during quiet standing with the berg balance scale in patients with parkinson's disease

BACKGROUND

Parkinson's disease (PD) is often clinically associated with posture instability and more easily falling. The Berg balance scale is a clinical indicator commonly used to subjectively evaluate a patient's balance ability. Meanwhile, computerized force platforms have been used in research on postural control. The various parameters obtained from posturography are interpreted to assess balance ability. The present study aims to explore the correlations between posturographic variables and the BBS, and furthermore to efficiently evaluate postural instability and fall risk of early and moderate PD patients.

METHODS

A total of 46 PD patients were involved in the experiment. Patients were asked to perform BBS tests and force platform tests under eye open (EO) and eye closed (EC) conditions. The recorded COP signal was analyzed with the time domain statistical method, the frequency domain method of Power Spectral Density (PSD), and structural methods of Stabilogram Diffusion Analysis (SDA), Sway Density Plot (SDP) to retrieve different posturographic variables. The correlation between posturographic variables under EO and EC conditions with BBS was compared statistically. The significantly correlated posturographic parameters were then applied to analyze posturographic differences between different groups: faller vs. non-faller (patients with/without a history of falls in the past 12 months).

RESULTS

Among the different posturographic parameters, the prediction ellipse area, the slope of the regression line at a high-frequency band of PSD in the medial-lateral (ML) direction, the crossover point of the regression lines of SDA in the anterior-posterior (AP) direction, and the distance between successive peaks of SDP had significant correlations with BBS. These selected BBS-related parameters also showed significant differences between faller and non-faller. The selected posturographic parameters can be used as effective indicators to evaluate the balance ability of Parkinson's disease patients.

Balance assessment in selected stages of Parkinson's disease using trend change analysis

BACKGROUND

Balance disorders in patients diagnosed with Parkinson's disease (PD) are associated with a change in balance-keeping strategy and reflex disorders which regulate the maintenance of vertical body posture. Center of foot pressure (COP) displacement signals were analyzed during quiet standing experiments to define such changes. The research aimed to apply stock exchange indices based on the trend change analyses to the assessment of a level of the Parkinson disease progression on the grounds of the analysis of the COP signals.

METHODS

30 patients in two stages of PD, 40 elderly participants, and 20 individuals at a young age were studied. Each person was subjected to 3 measurements with open and closed eyes. A technical analysis of the COP displacement signal was performed, and the following quantities were determined: indices related to the number of trend changes (TCI), indices defining a mean time (TCI_dT), and mean displacement (TCI_dS) and mean velocity (TCI_dV) between such changes.

RESULTS

The results indicate a higher TCI value for PD than for aged-matched control group (p < 0.05). In the case of PD patients, there was also an increase in the TCI_dS value by 2-5 mm, which mainly contributed to the increase in TCI_dV. Statistically significant differences for the TCI_dT values occurred between all groups in which differences in the average COP velocity were noted.

CONCLUSIONS

The TCI and TCI_dV results obtained for the healthy participants enabled the development of indices supporting PD diagnostics. The causes of the TCI_dV changes in patients were determined, i.e., whether they resulted from an increase in the TCI_dT or TCI_dS between the moments of trend changes indicated by the developed algorithm. The developed methodology provides new information on the impact of PD on the strategy of maintaining balance, which was impossible to obtain using currently used analyses. Trial registration The conducted research is an observational study and does not include a health care intervention. Participants gave their consent to participate in the research and the procedure was approved by the Institutional Bioethics Committee.

Advances in Biomechanics-Based Motion Analysis

Motion patterns in humans have been closely associated with neurological/musculoskeletal/behavioral/psychological health issues and competitive sports performance [...].