Clinical syndromes: Parkinsonian gait

Optimal subthalamic stimulation sites and related networks for freezing of gait in Parkinson's disease

Freezing of gait is a common and debilitating symptom in Parkinson's disease. Although high-frequency subthalamic deep brain stimulation is an effective treatment for Parkinson's disease, post-operative freezing of gait severity has been reported to alleviate, deteriorate or remain constant. We conducted this study to explore the optimal stimulation sites and related connectivity networks for high-frequency subthalamic deep brain stimulation treating freezing of gait in Parkinson's disease. A total of 76 Parkinson's disease patients with freezing of gait who underwent bilateral high-frequency subthalamic stimulation were retrospectively included. The volumes of tissue activated were estimated based on individual electrode reconstruction. The optimal and sour stimulation sites were calculated at coordinate/voxel/mapping level and mapped to anatomical space based on patient-specific images and stimulation settings. The structural and functional predictive connectivity networks for the change of the post-operative Freezing of Gait-Questionnaire were also identified based on normative connectomes derived from the Parkinson's Progression Marker Initiative database. Leave-one-out cross-validation model validated the above results, and the model remained significant after including covariates. The dorsolateral two-thirds of the subthalamic nucleus was identified as the optimal stimulation site, while the ventrocentral portion of the right subthalamic nucleus and internal capsule surrounding the left central subthalamic nucleus were considered as the sour stimulation sites. Modulation of the fibre tracts connecting to the supplementary motor area, pre-supplementary motor area and pedunculopontine nucleus accounted for the alleviation of freezing of gait, whereas tracts connecting to medial and ventrolateral prefrontal cortices contributed to the deterioration of freezing of gait. The optimal/sour stimulation sites and structural/functional predictive connectivity networks for high-frequency subthalamic deep brain stimulation treating freezing of gait are identified and validated through sizable Parkinson's disease patients in this study. With the growing understanding of stimulation sites and related networks, individualized deep brain stimulation treatment with directional leads will become an optimal choice for Parkinson's disease patients with freezing of gait in the future.

Evaluating Gait Impairment in Parkinson's Disease from Instrumented Insole and IMU Sensor Data

Parkinson's disease (PD) is characterized by a variety of motor and non-motor symptoms, some of them pertaining to gait and balance. The use of sensors for the monitoring of patients' mobility and the extraction of gait parameters, has emerged as an objective method for assessing the efficacy of their treatment and the progression of the disease. To that end, two popular solutions are pressure insoles and body-worn IMU-based devices, which have been used for precise, continuous, remote, and passive gait assessment. In this work, insole and IMU-based solutions were evaluated for assessing gait impairment, and were subsequently compared, producing evidence to support the use of instrumentation in everyday clinical practice. The evaluation was conducted using two datasets, generated during a clinical study, in which patients with PD wore, simultaneously, a pair of instrumented insoles and a set of wearable IMU-based devices. The data from the study were used to extract and compare gait features, independently, from the two aforementioned systems. Subsequently, subsets comprised of the extracted features, were used by machine learning algorithms for gait impairment assessment. The results indicated that insole gait kinematic features were highly correlated with those extracted from IMU-based devices. Moreover, both had the capacity to train accurate machine learning models for the detection of PD gait impairment.

Neuromelanin magnetic resonance imaging of substantia nigra and locus coeruleus in Parkinson's disease with freezing of gait

Background

The downregulation of monoamines, especially dopamine in substantia nigra (SN) and norepinephrine in locus coeruleus (LC), may be responsible for freezing of gait (FOG) pathological basis in Parkinson's disease (PD).

Methods

Thirty-two Parkinson's disease patients with freezing of gait (PD-FOG), 32 Parkinson's disease patients without freezing of gait (PD-NFOG) and 32 healthy controls (HC) underwent neuromelanin magnetic resonance imaging (NM-MRI). The volume, surface area and contrast to noise ratio (CNR) of SN and LC were measured and compared. The correlation analyses were conducted between the measurements of SN and LC with clinical symptoms. We plotted the receiver operating characteristic (ROC) curve and determined the sensitivity and specificity of the CNR of SN and LC for discriminating the PD-FOG from the PD-NFOG.

Results

Both PD-FOG and PD-NFOG showed decreased volume, surface area and CNR of SN compared with HC. The PD-FOG exhibited decreased volume and surface area of LC compared with both PD-NFOG and HC groups, and decreased CNR of LC compared with HC group. The volume, surface area and CNR of SN were negatively correlated with the Unified Parkinson's Disease Rating Scale part III scores. The illness durations in PD patients were negatively correlated with the volume, surface area of SN, while not the CNR. And the volume and surface area of LC were negatively correlated with new freezing of gait questionnaire scores. ROC analyses indicated that the area under the curve (AUC) was 0.865 and 0.713 in the CNR of SN and LC, respectively, in PD versus HC, whereas it was 0.494 and 0.637 respectively, in PD-FOG versus PD-NFOG. Among these, for discriminating the PD from the HC, the sensitivity and specificity in the CNR of the SN was 90.6 and 71.9%, respectively, when the cut-off value was set at 2.101; the sensitivity and specificity in the CNR of the LC was 90.6 and 50.0%, respectively, when the cut-off value for CNR was set at 1.411.

Conclusion

The dopaminergic changes in the SN were found across both PD-FOG and PD-NFOG, whilst LC noradrenergic neuron reduction was more evident in PD-FOG.

Treadmill training in Parkinson’s disease is underpinned by the interregional connectivity in cortical-subcortical network

Treadmill training (TT) has been extensively used as an intervention to improve gait and mobility in patients with Parkinson’s disease (PD). Regional and global effects on brain activity could be induced through TT. Training effects can lead to a beneficial shift of interregional connectivity towards a physiological range. The current work investigates the effects of TT on brain activity and connectivity during walking and at rest by using both functional near-infrared spectroscopy and functional magnetic resonance imaging. Nineteen PD patients (74.0 ± 6.59 years, 13 males, disease duration 10.45 ± 6.83 years) before and after 6 weeks of TT, along with 19 age-matched healthy controls were assessed. Interregional effective connectivity (EC) between cortical and subcortical regions were assessed and its interrelation to prefrontal cortex (PFC) activity. Support vector regression (SVR) on the resting-state ECs was used to predict prefrontal connectivity. In response to TT, EC analysis indicated modifications in the patients with PD towards the level of healthy controls during walking and at rest. SVR revealed cerebellum related connectivity patterns that were associated with the training effect on PFC. These findings suggest that the potential therapeutic effect of training on brain activity may be facilitated via changes in compensatory modulation of the cerebellar interregional connectivity.

Associated factors and abnormal dorsal raphe nucleus connectivity patterns of freezing of gait in Parkinson's disease

BACKGROUND

Freezing of gait (FOG) is a common, disabling symptom of Parkinson's disease (PD), and its exact pathophysiological mechanism is still poorly understood. The control of gait is a complex process that may be influenced by emotions modulated by serotonergic networks. Therefore, this study aimed to determine factors associated with FOG in PD patients and to evaluate the importance of the dorsal raphe nucleus (DRN; central node in the serotoninergic system) in FOG pathophysiology.

METHODS

We combined cross-sectional survey data from 453 PD patients. According to the Freezing of Gait Questionnaire (FOGQ), patients were divided into two groups: the "PD with frozen gait (PD-FOG)" and "PD without frozen gait (PD-nFOG)" groups. Demographic characteristics, clinical features, and motor and nonmotor symptoms (NMS) assessments of PD patients were recorded. Univariate statistical analysis was performed between the two groups, and then regression analysis was performed on related factors. We also acquired resting-state functional MRI (rs-fMRI) data from 20 PD-FOG, 21 PD-nFOG, and 22 healthy controls (HCs) who were randomly chosen. We defined seeds in the DRN to evaluate functional connectivity (FC) patterns.

RESULTS

The overall frequency of FOG was 11.9% patients in the PD-FOG group were older, had a longer disease duration, had a higher levodopa equivalent daily dose, had more severe motor symptoms and worse quality of life, had a higher proportion of dyskinesia, wearing-off and postural instability/gait difficulty (PIGD) clinical phenotype, and experienced more depression and impaired sleep function than those in the PD-nFOG group. Logistic regression analysis showed that H&Ystage ≥ 3, UPDRS-III scores, PIGD clinical phenotype and excessive daytime sleepiness were associated with FOG. In addition, there was significantly lower FC between the DRN and some cortical structures, including the supplementary motor area (SMA), left superior frontal gyrus (SFG), and left median cingulated cortex (MCC) in PD-FOG patients than HCs and PD-nFOG patients.

CONCLUSIONS

These results demonstrate that the severity of PD and PIGD clinical phenotype are associated factors for freezing and that DRN dysfunction may play a key role in PD-related NMS and FOG. An abnormal cortical and brainstem networks may contribute to the mechanisms underlying FOG.

Troubleshooting Gait Disturbances in Parkinson's Disease With Deep Brain Stimulation

Deep brain stimulation (DBS) of the subthalamic nucleus or the globus pallidus is an established treatment for Parkinson's disease (PD) that yields a marked and lasting improvement of motor symptoms. Yet, DBS benefit on gait disturbances in PD is still debated and can be a source of dissatisfaction and poor quality of life. Gait disturbances in PD encompass a variety of clinical manifestations and rely on different pathophysiological bases. While gait disturbances arising years after DBS surgery can be related to disease progression, early impairment of gait may be secondary to treatable causes and benefits from DBS reprogramming. In this review, we tackle the issue of gait disturbances in PD patients with DBS by discussing their neurophysiological basis, providing a detailed clinical characterization, and proposing a pragmatic programming approach to support their management.

Walking orientation randomness metric (WORM) score: pilot study of a novel gait parameter to assess walking stability and discriminate fallers from non-fallers using wearable sensors

Background

Musculoskeletal disorders can contribute to injurious falls and incur significant societal and healthcare burdens. Identification of fallers from non-fallers through wearable-based gait analysis can facilitate timely intervention to assist mobility and prevent falls whilst improving care and attention for high fall-risk patients. In this study, we use wearable sensor-based gait analysis to introduce a novel variable to assess walking stability in fallers and non-fallers – the Walking Orientation Randomness Metric. The WORM score quantifies the stability, or ‘figure-of-eight’ motion of a subject’s trunk during walking as an indicator of a falls-predictive (pathological) gait.

Methods

WORM is calculated as the ‘figure-of-eight’ oscillation mapped out in the transverse-plane by the upper body’s centre-point during a walking bout. A sample of patients presenting to the Prince of Wales Hospital (Sydney, Australia) with a primary diagnosis of “falls for investigation” and age-matched healthy controls (non-fallers) from the community were recruited. Participants were fitted at the sternal angle with the wearable accelerometer, MetaMotionC (Mbientlab Inc., USA) and walked unobserved (at self-selected pace) for 5-50 m along an obstacle-free, carpeted hospital corridor.

Results

Participants comprised of 16 fallers (mean age: 70 + 17) and 16 non-fallers (mean age: 70 + 9) based on a recent fall(s) history. The (median) WORM score was 17-fold higher (p < 0.001) in fallers (3.64 cm) compared to non-fallers (0.21 cm). ROC curve analyses demonstrate WORM can discriminate fallers from non-fallers (AUC = 0.97). Diagnostic analyses (cut-off > 0.51 cm) show high sensitivity (88%) and specificity (94%).

Conclusion

In this pilot study we have introduced the WORM score, demonstrating its discriminative performance in a preliminary sample size of 16 fallers. WORM is a novel gait metric assessing walking stability as measured by truncal way during ambulation and shows promise for objective and clinical evaluation of fallers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05211-1.

Proof of Concept in Artificial-Intelligence-Based Wearable Gait Monitoring for Parkinson's Disease Management Optimization

Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder, affecting 6.2 million patients and causing disability and decreased quality of life. The research is oriented nowadays toward artificial intelligence (AI)-based wearables for early diagnosis and long-term PD monitoring. Our primary objective is the monitoring and assessment of gait in PD patients. We propose a wearable physiograph for qualitative and quantitative gait assessment, which performs bilateral tracking of the foot biomechanics and unilateral tracking of arm balance. Gait patterns are assessed by means of correlation. The surface plot of a correlation coefficient matrix, generated from the recorded signals, is classified using convolutional neural networks into physiological or PD-specific gait. The novelty is given by the proposed AI-based decisional support procedure for gait assessment. A proof of concept of the proposed physiograph is validated in a clinical environment on five patients and five healthy controls, proving to be a feasible solution for ubiquitous gait monitoring and assessment in PD. PD management demonstrates the complexity of the human body. A platform empowering multidisciplinary, AI-evidence-based decision support assessments for optimal dosing between drug and non-drug therapy could lay the foundation for affordable precision medicine.

Relevance of Sociodemographics and Clinical Tests in Single- and Dual-Task Conditions as Gait Speed Predictors of Parkinson’s Disease

This cross-sectional study aimed to identify the patient characteristics and clinical test results that predict the functional gait speed of people with Parkinson’s disease (PD). The impact of dual tasks on gait in Parkinson’s disease (PD) reveals a lack of automaticity and increased cognitive demands. We explored which characteristics explained walking speed with and without dual-task interference and if they reflected the cognitive demands of the task. The preferred gait speed, stride length, and cadence were measured in individuals with PD through five conditions: single-task (ST) and visual, verbal, auditory, and motor dual-tasks (DTs). Sociodemographic and disease characteristics and the results from clinical tests such as the Dynamic Parkinson’s Disease Gait Scale (DYPAGS), Frontal Assessment Battery (FAB), and Parkinson’s Disease Questionnaire-39 (PDQ-39), among others, were also recorded. Two models of multiple regression analysis were used to explore the predictive value of outcomes concerning speed. In Model I, clinical results were included, and in Model II, spatiotemporal variables were added to the significant predictors of Model I. Forty PD patients (aged 66.72 (7.5) years) completed the assessments. All the models generated were significant (p < 0.01). Models I and II accounted for 47% and 93% of the variance, respectively, in the single-task condition. A patient’s gender, prescribed medication (drugs), academic level, and Hoehn and Yahr (H&Y) stage, along with the FAB, DYPAGS, and PDQ-39 scores, were significant predictors of gait speed in Model I for the ST and DT conditions. In Model II, the H&Y stage and prescribed medication (drugs), along with the FAB and DYPAGS scores, remained significant predictors. This research found that sociodemographics, the patient’s stage disease, and their clinical test results contribute to their walking speed, highlighting the multifactorial nature of gait in demanding environments.

Comparison of Shod and Unshod Gait in Patients With Parkinson's Disease With Subthalamic and Nigral Stimulation

Background: The Parkinsonian [i.e., Parkinson's disease (PD)] gait disorder represents a therapeutical challenge with residual symptoms despite the use of deep brain stimulation of the subthalamic nucleus (STN DBS) and medical and rehabilitative strategies. The aim of this study was to assess the effect of different DBS modes as combined stimulation of the STN and substantia nigra (STN+SN DBS) and environmental rehabilitative factors as footwear on gait kinematics.

Methods: This single-center, randomized, double-blind, crossover clinical trial assessed shod and unshod gait in patients with PD with medication in different DBS conditions (i.e., STIM OFF, STN DBS, and STN+SN DBS) during different gait tasks (i.e., normal gait, fast gait, and gait during dual task) and compared gait characteristics to healthy controls. Notably, 15 patients participated in the study, and 11 patients were analyzed after a dropout of four patients due to DBS-induced side effects.

Results: Gait was modulated by both factors, namely, footwear and DBS mode, in patients with PD. Footwear impacted gait characteristics in patients with PD similarly to controls with longer step length, lower cadence, and shorter single-support time. Interestingly, DBS exerted specific effects depending on gait tasks with increased cognitive load. STN+SN DBS was the most efficient DBS mode compared to STIM OFF and STN DBS with intense effects as step length increment during dual task.

Conclusion: The PD gait disorder is a multifactorial symptom, impacted by environmental factors as footwear and modulated by DBS. DBS effects on gait were specific depending on the gait task, with the most obvious effects with STN+SN DBS during gait with increased cognitive load.

Configurable Offline Sensor Placement Identification for a Medical Device Monitoring Parkinson's Disease

Sensor placement identification in body sensor networks is an important feature, which could render such a system more robust, transparent to the user, and easy to wear for long term data collection. It can be considered an active measure to avoid the misuse of a sensing system, specifically as these platforms become more ubiquitous and, apart from their research orientation, start to enter industries, such as fitness and health. In this work we discuss the offline, fixed class, sensor placement identification method implemented in PDMonitor^®, a medical device for long-term Parkinson’s disease monitoring at home. We analyze the stepwise procedure used to accurately identify the wearables depending on how many are used, from two to five, given five predefined body positions. Finally, we present the results of evaluating the method in 88 subjects, 61 Parkinson’s disease patients and 27 healthy subjects, when the overall average accuracy reached 99.1%.

Towards real-world generalizability of a circuit for action-stopping

Two decades of cross-species neuroscience research on rapid action-stopping in the laboratory has provided motivation for an underlying prefrontal-basal ganglia circuit. Here we provide an update of key studies from the past few years. We conclude that this basic neural circuit is on increasingly firm ground, and we move on to consider whether the action-stopping function implemented by this circuit applies beyond the simple laboratory stop signal task. We advance through a series of studies of increasing 'real-worldness', starting with laboratory tests of stopping of speech, gait and bodily functions, and then going beyond the laboratory to consider neural recordings and stimulation during moments of control presumably required in everyday activities such as walking and driving. We end by asking whether stopping research has clinical relevance, focusing on movement disorders such as stuttering, tics and freezing of gait. Overall, we conclude there are hints that the prefrontal-basal ganglia action-stopping circuit that is engaged by the basic stop signal task is recruited in myriad scenarios; however, truly proving this for real-world scenarios requires a new generation of studies that will need to overcome substantial technical and inferential challenges.

Can Task Specificity Impact tDCS-Linked to Dual Task Training Gains in Parkinson's Disease? A Protocol for a Randomized Controlled Trial

Patients with Parkinson's disease (PD) have difficulties while performing dual-task activities, a condition present in everyday life. It is possible that strategies such as transcranial Direct Current Stimulation (tDCS) can be associated with motor training enriched with dual-task training to improve the performance of two concurrent tasks. Currently, it is unclear whether specific tasks and clinical conditions of PD patients have different results after the intervention. Therefore, the proposed randomized controlled trial will examine task-dependency in enhancing the effects of tDCS-linked rehabilitation training on PD and the relationships between baseline outcomes in responders and non-responders to therapy. Fifty-six patients with Parkinson's disease will be recruited to participate in this controlled, double-blind randomized multicentric clinical trial. Patients in modified Hoehn & Yahr stage 1.5-3, age between 40 and 70 years will be included. Subjects will be randomly assigned to an experimental group (EG) and a control group (CG). The EG will perform treadmill gait training associated with dual task exercises+tDCS, while the CG will only engage in treadmill gait training+tDCS. Blinded testers will assess patients before and after 12 intervention sessions and after a 4-week follow-up period. All patients will undergo a screening and an initial visit before being assessed for primary and secondary outcomes. The primary outcome measure is functional mobility measured by Timed Up and Go Test. Secondary outcomes include cognitive function, participation, motor function and body function and structure. This study will evaluate the effectiveness of an intervention protocol with tDCS, dual-task training and gait training in patients with PD. The study will also highlight the clinical factors and variability between individuals that could interfere in the training of a specific task and influence the therapeutic effect. Clinical Trial registration: www.ClinicalTrials.gov, identifier NCT04581590.

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

INTRODUCTION

Both 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.

METHODS

Community 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.

RESULTS

Seventy-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.

DISCUSSION

Gait 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.

Body Weight Support Gait Training for Patients With Parkinson Disease: A Systematic Review and Meta-analyses

OBJECTIVE

To determine the effectiveness of body weight support (BWS) gait training to improve the clinical severity, gait, and balance in patients with Parkinson disease (PD).

DATA SOURCES

A literature search was conducted until July 2020 in MEDLINE, Physiotherapy Evidence Database, Cochrane Central Register of Controlled Trials, and Cumulative Index to Nursing and Allied Health Literature.

STUDY SELECTION

Randomized controlled trials that aimed at determining the effectiveness of physical activity interventions with BWS during gait training in patients with PD.

DATA EXTRACTION

The methodological quality of randomized controlled trials was assessed using the Cochrane risk of bias tool (RoB 2.0). Effect size (ES) and 95% confidence intervals [CIs] were calculated for the Unified Parkinson Disease Rating Scale (UPDRS), the UPDRS section III, the 6-minute walk test (6MWT), gait parameters (ie, velocity, cadence, stride length), and the Berg Balance Scale (BBS).

DATA SYNTHESIS

Twelve studies were included in the systematic review. The pooled ES for the effect of BWS on total UPDRS was -0.35 (95% CI, -0.57 to -0.12; I²=1.9%, P=.418), whereas for UPDRS III it was -0.35 (95% CI, -0.68 to -0.01; I²=66.4 %, P<.001). Furthermore, the pooled ES for 6MWT was 0.56 (95% CI, -0.07 to 1.18; I²=77.1%, P=.002), for gait velocity was 0.37 (95% CI, -0.10 to 0.84); I²=78.9%, P<.001), for cadence was 0.03 (95% CI, -0.25 to 0.30; I²=0.0%, P=.930), for stride length was 1.00 (95% CI, 0.23 to 1.78; I²=79.5%, P=.001), and for BBS was 0.65 (95% CI, 0.30, 0.99; I²=51.8%, P=.042).

CONCLUSIONS

Interventions with BWS could improve the general and motor clinical severity of patients with PD, as well as other parameters such as stride length and balance. However, the effect does not appear to be statistically significant in improving gait parameters such as velocity, cadence, and distance.

The Impact of Reducing the Number of Wearable Devices on Measuring Gait in Parkinson Disease: Noninterventional Exploratory Study

Background

Measuring free-living gait using wearable devices may offer higher granularity and temporal resolution than the current clinical assessments for patients with Parkinson disease (PD). However, increasing the number of devices worn on the body adds to the patient burden and impacts the compliance.

Objective

This study aimed to investigate the impact of reducing the number of wearable devices on the ability to assess gait impairments in patients with PD.

Methods

A total of 35 volunteers with PD and 60 healthy volunteers performed a gait task during 2 clinic visits. Participants with PD were assessed in the On and Off medication state using the Movement Disorder Society version of the Unified Parkinson Disease Rating Scale (MDS-UPDRS). Gait features derived from a single lumbar-mounted accelerometer were compared with those derived using 3 and 6 wearable devices for both participants with PD and healthy participants.

Results

A comparable performance was observed for predicting the MDS-UPDRS gait score using longitudinal mixed-effects model fit with gait features derived from a single (root mean square error [RMSE]=0.64; R2=0.53), 3 (RMSE=0.64; R2=0.54), and 6 devices (RMSE=0.54; R2=0.65). In addition, MDS-UPDRS gait scores predicted using all 3 models differed significantly between On and Off motor states (single device, P=.004; 3 devices, P=.004; 6 devices, P=.045).

Conclusions

We observed a marginal benefit in using multiple devices for assessing gait impairments in patients with PD when compared with gait features derived using a single lumbar-mounted accelerometer. The wearability burden associated with the use of multiple devices may offset gains in accuracy for monitoring gait under free-living conditions.

Freezing of gait: understanding the complexity of an enigmatic phenomenon

Diverse but complementary methodologies are required to uncover the complex determinants and pathophysiology of freezing of gait. To develop future therapeutic avenues, we need a deeper understanding of the disseminated functional-anatomic network and its temporally associated dynamic processes. In this targeted review, we will summarize the latest advances across multiple methodological domains including clinical phenomenology, neurogenetics, multimodal neuroimaging, neurophysiology, and neuromodulation. We found that (i) locomotor network vulnerability is established by structural damage, e.g. from neurodegeneration possibly as result from genetic variability, or to variable degree from brain lesions. This leads to an enhanced network susceptibility, where (ii) modulators can both increase or decrease the threshold to express freezing of gait. Consequent to a threshold decrease, (iii) neuronal integration failure of a multilevel brain network will occur and affect one or numerous nodes and projections of the multilevel network. Finally, (iv) an ultimate pathway might encounter failure of effective motor output and give rise to freezing of gait as clinical endpoint. In conclusion, we derive key questions from this review that challenge this pathophysiological view. We suggest that future research on these questions should lead to improved pathophysiological insight and enhanced therapeutic strategies.

Gait pattern analysis and clinical subgroup identification: a retrospective observational study

To identify basic gait features and abnormal gait patterns that are common to different neurological or musculoskeletal conditions, such as cerebral stroke, Parkinsonian disorders, radiculopathy, and musculoskeletal pain.In this retrospective study, temporal-spatial, kinematic, and kinetic gait parameters were analyzed in 424 patients with hemiplegia after stroke, 205 patients with Parkinsonian disorders, 216 patients with radiculopathy, 167 patients with musculoskeletal pain, and 316 normal controls (total, 1328 subjects). We assessed differences according to the condition and used a community detection algorithm to identify subgroups within each condition. Additionally, we developed a prediction model for subgroup classification according to gait speed and maximal hip extension in the stance phase.The main findings can be summarized as follows. First, there was an asymmetric decrease of the knee/ankle flexion angles in hemiplegia and a marked reduction of the hip/knee range of motion with increased moment in Parkinsonian disorders. Second, three abnormal gait patterns, including fast gait speed with adequate maximal hip extension, fast gait speed with inadequate maximal hip extension, and slow gait speed, were found throughout the conditions examined. Third, our simple prediction model based on gait speed and maximal hip extension angle was characterized by a high degree of accuracy in predicting subgroups within a condition.Our findings suggest the existence of specific gait patterns within and across conditions. Our novel subgrouping algorithm can be employed in routine clinical settings to classify abnormal gait patterns in various neurological disorders and guide the therapeutic approach and monitoring.

Assessing the Relationship between the Enhanced Gait Variability Index and Falls in Individuals with Parkinson's Disease

Gait impairment and increased gait variability are common among individuals with Parkinson's disease (PD) and have been associated with increased risk for falls. The development of composite scores has gained interest to aggregate multiple aspects of gait into a single metric. The Enhanced Gait Variability Index (EGVI) was developed to compare an individual's gait variability to the amount of variability in a healthy population, yet the EGVI's individual parts may also provide important information that may be lost in this conversion. We sought to contrast individual gait measures as predictors of fall frequency and the EGVI as a single predictor of fall frequency in individuals with PD. 273 patients (189M, 84F; 68 ± 10 yrs) with idiopathic PD walked over an instrumented walkway and reported fall frequency over three months (never, rarely, monthly, weekly, or daily). The predictive ability of gait velocity, step length, step time, stance time, and single support time and the EGVI was assessed using regression techniques to predict fall frequency. The EGVI explained 15.1% of the variance in fall frequency (p < 0.001, r = 0.389). Although the regression using the combined spatiotemporal measures to predict fall frequency was significant (p=0.002, r = 0.264), none of the components reached significance (gait velocity: p=0.640, step length: p=0.900, step time: p=0.525, stance time: p=0.532, single support time: p=0.480). The EGVI is a better predictor of fall frequency in persons with PD than its individual spatiotemporal components. Patients who fall more frequently have more variable gait, based on the interpretation of the EGVI. While the EGVI provides an objective measure of gait variability with some ability to predict fall frequency, full clinical interpretations and applications are currently unknown.

Asymmetric dynamic center-of-pressure in Parkinson's disease

BACKGROUND

Gait disturbance gradually worsens as Parkinson's disease (PD) progresses, which significantly affects the quality of life of PD patients. Treadmill-based gait analysis systems can measure gait parameters including the dynamic center-of-pressure (COP) trajectory during ambulation. In this study, we hypothesized that altered dynamic COP changes are new gait characteristics for PD patients.

METHODS

Dynamic COP parameters and classic spatiotemporal parameters were obtained for each patient using a treadmill-based system at the maximal comfortable treadmill speed (MCTS). We compared dynamic COP parameters between 44 PD patients and 31 controls, correlated these parameters with clinical and spatiotemporal data, and adjusted for age and MCTS to determine whether the parameters were independent from the treadmill speed. We also evaluated characteristics of COP parameters in relation to the more and less affected sides in PD patients.

RESULTS

During treadmill walking the length of the COP trajectory in the stance phase was decreased, an effect that was more prominent on the more affected side in PD patients. COP parameters related to this change were significantly altered in patients when compared to controls. Asymmetry of the COP trajectories compared between both feet was identified as a significant gait characteristic after adjusting for age and MCTS. The overlaid graphical display of dynamic COP trajectory in PD patients showed "distorted butterfly with asymmetric wing" feature.

CONCLUSION

Dynamic COP asymmetry provides a new and intuitive way to analyze gait abnormalities of PD patients. Further studies with prospective designs will substantiate the clinical usefulness of this feature of gait.

The Effects of Music-Contingent Gait Training on Cognition and Mood in Parkinson Disease: A Feasibility Study

Background. In Parkinson disease (PD), gait impairments often coexist with nonmotor symptoms such as anxiety and depression. Biofeedback training may improve gait function in PD, but its effect on nonmotor symptoms remains unclear. This study explored the cognitive and global effects of Ambulosono, a cognitive gait training method utilizing step size to contingently control the real-time play of motivational music. Objective. This study examined the feasibility of music-contingent gait training and its effects on neuropsychological test performance and mood in persons with PD. Methods. A total of 30 participants with mild to moderate PD were semirandomized via sequential alternating assignment into an experimental training group or control music group. The training group received 12 weeks of music-contingent training, whereby music play was dependent on the user achieving a set stride length, adjusted online based on individual performance. The control group received hybrid training beginning with 6 weeks of noncontingent music walking, whereby music played continuously regardless of step size, followed by 6 weeks of music-contingent training. Global cognition, memory, executive function, attention, and working memory assessments were completed by blinded assessors at baseline, 6 weeks, and 12 weeks. Motor function, mood, and anxiety were assessed. Results. Average training adherence was 97%, with no falls occurring during training sessions. Improvements on cognitive measures were not clinically significant; however, significant decreases in depression and anxiety were observed in both groups over time (P < .05). Conclusions. Music-contingent gait training is feasible and safe in individuals with PD. Further investigation into potential therapeutic applications of this technology is recommended.

[Deep brain stimulation effect on postural instability and gait disorders in Parkinson's disease]

An effect of deep brain stimulation on postural instability and gait disorders in Parkinson's disease S.G. Sultanova, N.V. Fedorova, E.V. Bril, A.A. Gamaleya, A.A. Tomskiy During the last time, surgical treatment of patients with Parkinson's disease has firmly taken its place in the general algorithm for managing patients with this pathology. Deep brain electrostimulation is the most advanced and promising method, which allows the reduction in the severity of main clinical manifestations of the disease, including axial symptoms. It is noted that certain temporal aspects of parkinsonian gait disorder remain therapeutically resistant. Subthalamic nucleus stimulation was also reported to improve levodopa-responsive freezing of gait. In this review, the authors summarize the effects of deep brain stimulation on gait and postural symptoms.

The Primary Gait Screen in Parkinson's disease: Comparison to standardized measures

BACKGROUND

Persons with Parkinson's disease exhibit gait deficits during comfortable-pace overground walking and data from pressure sensitive mats have been used to quantify gait performance. The Primary Gait Screen is a new assessment which includes gait initiation, overground walking, turning, and gait termination. Although overground assessments are useful, the Primary Gait Screen offers a more complex evaluation than traditional gait assessments.

RESEARCH QUESTION

Is the overground walking portion of the Primary Gait Screen comparable to traditional gait assessments?

METHODS

Persons with Parkinson's disease (N = 175; 47 F, 128 M; 67 ± 9 yrs) prospectively completed 4 passes at a self-selected speed and two trials of the Primary Gait Screen on an 8 m long pressure-sensing mat. Spatiotemporal gait variables were computed and a repeated-measures MANOVA with a Bonferroni correction compared the spatiotemporal variables from the Primary Gait Screen to the self-selected trials: gait velocity, cadence, step length, step time, and stride length.

RESULTS

The analyses failed to detect differences between the Primary Gait Screen and self-selected trials for gait velocity, step length, or stride length (p > .01). Post-hoc tests revealed decreased cadence and increased step time were the only differences between the Primary Gait Screen trials and the self-selected trial (p < .001).

SIGNIFICANCE

Differences seen in cadence and step time during the Primary Gait Screen may be attributed to patients' strategy, but are likely not clinically meaningful. The Primary Gait Screen appears to be a comparable assessment of overground walking in persons with Parkinson's disease, and may be a useful and accurate clinical assessment of walking.

Immediate effects of rhythmic auditory stimulation on gait kinematics in Parkinson's disease ON/OFF medication

OBJECTIVE

Gait impairment is a highly disabling symptom for Parkinson's disease (PD) patients. Rhythmic auditory stimulation (RAS), has shown to improve spatio-temporal gait parameters in PD, but only a few studies have focused on their effects on gait kinematics, and the ideal stimulation frequency has still not been identified.

METHODS

We enrolled 30 PD patients and 18 controls. Patients were evaluated under two conditions (with (ON), and without (OFF) medications) with three different RAS frequencies (90%, 100%, and 110% of the patient's preferred walking cadence). Spatial-temporal parameters, joint angles and gait phases distribution were evaluated. A novel global index (GPQI) was used to quantify the difference in gait phase distribution.

RESULTS

Along with benefits in spatial-temporal parameters, GPQI improved significantly with RAS at a frequency of 110% for both ON and OFF medication conditions. In the most severe patients, the same result was observed also with RAS at 100%.

CONCLUSIONS

RAS administration, at a frequency of 110% of the preferred walking frequency, can be beneficial in improving the gait pattern in PD patients.

SIGNIFICANCE

When rhythmic auditory stimulation is provided to patients with PD, the selection of an adequate frequency of stimulation can optimize their effects on gait pattern.

Gait and postural disorders in parkinsonism: a clinical approach

Disturbances of balance, gait and posture are a hallmark of parkinsonian syndromes. Recognition of these axial features can provide important and often early clues to the nature of the underlying disorder, and, therefore, help to disentangle Parkinson’s disease from vascular parkinsonism and various forms of atypical parkinsonism, including multiple system atrophy, progressive supranuclear palsy, and corticobasal syndrome. Careful assessment of axial features is also essential for initiating appropriate treatment strategies and for documenting the outcome of such interventions. In this article, we provide an overview of balance, gait and postural impairment in parkinsonian disorders, focusing on differential diagnostic aspects.

Beat perception ability and instructions to synchronize influence gait when walking to music-based auditory cues

Synchronizing gait to music-based auditory cues (rhythmic auditory stimulation) is a strategy used to manage gait impairments in a variety of neurological conditions, including Parkinson's disease. However, knowledge of how to individually optimize music-based cues is limited. The purpose of this study was to investigate how instructions to synchronize with auditory cues influences gait outcomes among healthy young adults with either good or poor beat perception ability. 65 healthy adults walked to metronome and musical stimuli with high and low levels of perceived groove (how much it induces desire to move) and familiarity at a tempo equivalent to their self-selected walking pace. Participants were randomized to instruction conditions: (i) synchronized: match footsteps with the beat, or (ii) free-walking: walk comfortably. Participants were classified as good or poor beat perceivers using the Beat Alignment Test. In this study, poor beat perceivers show better balance-related parameters (stride width and double-limb support time) when they are not instructed to synchronize their gait with cues (versus when synchronization was required). Good beat perceivers, in contrast, were better when instructed to synchronize gait (versus when no synchronization was required). Changes in stride length and velocity were influenced by musical properties, in particular the perceived 'groove' (greater stride length and velocity with high- versus low-groove cues) and, in some cases, this interacted with beat perception ability. The results indicate that beat perception ability and instructions to synchronize indeed influence spatiotemporal gait parameters when walking to music- and metronome-based rhythmic auditory stimuli. Importantly, these results suggest that both low groove cues and instructing poor beat perceivers to synchronize may interfere with performance while walking, thus potentially impacting both empirical and clinical outcomes.

Mesencephalic and extramesencephalic dopaminergic systems in Parkinson's disease

Neurodegeneration of the nigrostriatal dopaminergic system and concurrent dopamine (DA) deficiency in the basal ganglia represent core features of Parkinson's disease (PD). Despite the central role of DA in the pathogenesis of PD, dopaminergic systems outside of the midbrain have not been systematically investigated for Lewy body pathology or neurodegeneration. Dopaminergic neurons show a surprisingly rich neurobiological diversity, suggesting that there is not one general type of dopaminergic neuron, but rather a spectrum of different dopaminergic phenotypes. This heterogeneity on the cellular level could account for the observed differences in susceptibility of the dopaminergic systems to the PD disease process. In this review, we will summarize the long history from the first description of PD to the rationally derived DA replacement therapy, describe the basal neuroanatomical and neuropathological features of the different dopaminergic systems in health and PD, explore how neuroimaging techniques broadened our view of the dysfunctional dopaminergic systems in PD and discuss how dopaminergic replacement therapy ameliorates the classical motor symptoms but simultaneously induces a new set of hyperdopaminergic symptoms.

Speed and temporal adaptations during nonmotorized treadmill walking in Parkinson disease and nondisabled individuals

Few studies have explored the potential of gait analysis and training in nonmotorized treadmill (NMT) in Parkinson's disease (PD) patients. We investigated (a) the walking strategy adopted by patients with PD on NMT and (b) how balance may influence spatiotemporal gait parameters. We enrolled 12 patients with PD of modified Hoehn and Yahr stage 2-3 and 13 nondisabled individuals as controls. All participants were evaluated using Tinetti's performance oriented mobility assessment scale, freezing of gait questionnaire, modified falls efficacy scale, and the timed up and go test. They were asked to ambulate with comfortable and maximal speeds on the NMT. The gait parameters acquired on the NMT included walking speed, cadence (CAD), step length, and vertical ground reaction force, which were calculated for intragroup and intergroup comparisons. The PD group took on with higher contribution of CAD and less contribution of step length to increase walking speed as compared with control group. The postural stability is correlated significantly positively to the CAD at the setting of maximal speed in the PD group. Moreover, a significantly lower ratio of vertical ground reaction force/body weight was noted in the PD group during both comfortable and maximal walking speeds compared with the nondisabled controls. Our study outcomes clearly support the perceived benefits of NMT to differentiate spatiotemporal gait parameters between PD and controls. NMT may potentially be useful to evaluate the recovery of physical activities in PD receiving medications and/or rehabilitation.

Relationships between gait and emotion in Parkinson's disease: A narrative review

BACKGROUND

Disturbance of gait is a key feature of Parkinson's disease (PD) and has a negative impact on quality of life. Deficits in cognition and sensorimotor processing impair the ability of people with PD to walk quickly, efficiently and safely. Recent evidence suggests that emotional disturbances may also affect gait in PD.

RESEARCH QUESTION

We explored if there were relationships between walking ability, emotion and cognitive impairment in people with PD.

METHODS

The literature was firstly reviewed for unimpaired individuals. The recent experimental evidence for the influence of emotion on gait in people with PD was then explored. The contribution of affective disorders to continuous gait disorders was investigated, particularly for bradykinetic and hypokinetic gait. In addition, we investigated the influence of emotional processing on episodic gait disturbances, such as freezing of gait. Potential effects of pharmacological, surgical and physical therapy interventions were also considered.

RESULTS

Emerging evidence showed that emotional disturbances arising from affective disorders such as anxiety and depression, in addition to cognitive impairment, could contribute to gait disorders in some people with PD. An analysis of the literature indicated mixed evidence that improvements in affective disorders induced by physical therapy, pharmacological management or surgery improve locomotion in PD.

SIGNIFICANCE

When assessing and treating gait disorders in people with PD, it is important to take into the account non-motor symptoms such as anxiety, depression and cognitive impairment, in addition to the motor sequalae of this progressive neurological condition.

Mobility device use in people with Parkinson's disease: A 3-year follow-up study

OBJECTIVES

This study aimed to investigate how the use and perceived unmet need of mobility devices (MD) in people with Parkinson's disease (PD) evolve over a 3-year period.

METHODS

The study reports baseline assessments (n = 255) and comparisons for participants with complete data at baseline and the 3-year follow-up (n = 165). Structured questions addressed the use and perceived unmet need of various MDs indoor and outdoor (eg, canes, wheeled walkers, and manual and powered wheelchairs). McNemar tests were used to investigate differences over time.

RESULTS

In the total sample at baseline, 30% and 52% of the participants reported using MDs indoors and outdoors, respectively. Among those with complete data also at the 3-year follow-up, the proportion of participants using MDs increased significantly (P < .001) from 22% to 40% for indoors and from 48% to 66% for outdoors, with transition of MD toward more assistive potential (ie, wheeled walker and manual wheelchair). Wheeled walkers were the most commonly used MD indoors as well as outdoors on both occasions. Among the users of multiple MDs, the most common combination was cane and wheeled walker on both occasions. The proportion of participants who reported a perceived unmet need of MDs was 5% at baseline, whereas it was 21%, 3 years later.

CONCLUSIONS

The use and perceived unmet need of MDs in people with PD increase over time. There is a need for addressing MDs at clinical follow-ups of people with PD, with continuous attention in primary health care and municipality contexts.

Gait Disorders

Walking is an extraordinarily complex task requiring integration of the entire nervous system, making gait susceptible to a variety of underlying neurologic abnormalities. Gait disorders are particularly prevalent in the elderly and increase fall risk. In this review we discuss an approach to the examination of gait and highlight key features of common gait disorders and their underlying causes. We review gaits due to lesions of motor systems (spasticity and neuromuscular weakness), the cerebellum and sensory systems (ataxia), parkinsonism, and frontal lobes and discuss the remarkably diverse phenomenology of functional (psychogenic) gait disorders. We offer a pragmatic approach to the diagnosis and management of neurologic gait disorders, because prompt recognition and intervention may improve quality of life in affected individuals.

Alternating Modulation of Subthalamic Nucleus Beta Oscillations during Stepping

Gait disturbances in Parkinson's disease are commonly refractory to current treatment options and majorly impair patient's quality of life. Auditory cues facilitate gait and prevent motor blocks. We investigated how neural dynamics in the human subthalamic nucleus of Parkinsons's disease patients (14 male, 2 female) vary during stepping and whether rhythmic auditory cues enhance the observed modulation. Oscillations in the beta band were suppressed after ipsilateral heel strikes, when the contralateral foot had to be raised, and reappeared after contralateral heel strikes, when the contralateral foot rested on the floor. The timing of this 20–30 Hz beta modulation was clearly distinct between the left and right subthalamic nucleus, and was alternating within each stepping cycle. This modulation was similar, whether stepping movements were made while sitting, standing, or during gait, confirming the utility of the stepping in place paradigm. During stepping in place, beta modulation increased with auditory cues that assisted patients in timing their steps more regularly. Our results suggest a link between the degree of power modulation within high beta frequency bands and stepping performance. These findings raise the possibility that alternating deep brain stimulation patterns may be superior to constant stimulation for improving parkinsonian gait.

SIGNIFICANCE STATEMENT Gait disturbances in Parkinson's disease majorly reduce patients' quality of life and are often refractory to current treatment options. We investigated how neural activity in the subthalamic nucleus of patients who received deep brain stimulation surgery covaries with the stepping cycle. 20–30 Hz beta activity was modulated relative to each step, alternating between the left and right STN. The stepping performance of patients improved when auditory cues were provided, which went along with enhanced beta modulation. This raises the possibility that alternating stimulation patterns may also enhance beta modulation and may be more beneficial for gait control than continuous stimulation, which needs to be tested in future studies.

Slowness in Movement Initiation is Associated with Proactive Inhibitory Network Dysfunction in Parkinson's Disease

BACKGROUND

Impairment in initiating movements in PD might be related to executive dysfunction associated with abnormal proactive inhibitory control, a pivotal mechanism consisting in gating movement initiation in uncertain contexts.

OBJECTIVE

Testing this hypothesis on the basis of direct neural-based evidence.

METHODS

Twelve PD patients on antiparkinsonian medication and fifteen matched healthy controls performed a simple reaction time task during event-related functional MRI scanning.

RESULTS

For all subjects, the level of activation of SMA was found to predict RT on a trial-by-trial basis. The increase in movement initiation latency observed in PD patients with regard to controls was associated with pre-stimulus BOLD increases within several nodes of the proactive inhibitory network (caudate nucleus, precuneus, thalamus).

CONCLUSIONS

These results provide physiological data consistent with impaired control of proactive inhibition over motor initiation in PD. Patients would be locked into a mode of control maintaining anticipated inhibition over willed movements even when the situation does not require action restraint. The functional and neurochemical bases of brain activity associated with executive settings need to be addressed thoroughly in future studies to better understand disabling symptoms that have few therapeutic options like akinesia.

Long-term Monitoring Gait Analysis Using a Wearable Device in Daily Lives of Patients with Parkinson's Disease: The Efficacy of Selegiline Hydrochloride for Gait Disturbance

Objective

The aim of this study was to assess quantitatively the gait disorders in the daily lives of patients with Parkinson’s disease (PD) using with a newly developed portable gait rhythmogram (PGR), which has a trunk-mounted acceleration sensor and automatic gait-detection algorithm.

Methods

Using the PGR, we recorded the daily walking profiles of 14 PD patients before and after the addition or increase in dose of an MAO-B inhibitor (selegiline, average dose: 4.0 mg/day) as part of their medicine regimen, and evaluated their gait using the unified Parkinson’s disease rating scale (UPDRS) and scores from a freezing of gait (FOG) questionnaire.

Results

Before treatment with selegiline, the overall movements per 24 h was decreased below 0.41 m/s² (mean − 1.5 SD) in eight patients. The mean gait acceleration was decreased below 1.94 m/s² (mean − 2 SD) in 10 patients. The slope of the linear regression line was increased to 1.6 (mean + 1.5 SD) in eight patients. The cadence was increased to 124 steps/min (mean + 1.5 SD) in four patients. Based on continuous PGR recordings in the daily lives of the patients for 24 h, the addition or increase in dose of selegiline increased the amplitudes of gait accelerations in 4 of 10 patients (40.0%), widened the range of gait accelerations in 5 of 8 patients (62.5%), diminished the cadence in 4 of 4 patients (100%), and diminished the fluctuations in gait throughout the day in 12 of 14 patients (85.7%). The UPDRS III and FOG scores significantly improved after the addition or increase in dose of selegiline (p < 0.005, p < 0.01, respectively). However, changes in gait-related scores of UPDRS were not detected in six patients.

Conclusion

Improvements in the gait fluctuations of PD patients after the addition or increase in dose of selegiline were detected using the PGR in the daily lives of the patients for 24 h. The PGR had a higher sensitivity for detecting the improvements than UPDRS scores.

The validity of the Gait Variability Index for individuals with mild to moderate Parkinson's disease

Increased step-to-step variability is a feature of gait in individuals with Parkinson's disease (PD) and is associated with increased disease severity and reductions in balance and mobility. The Gait Variability Index (GVI) quantifies gait variability in spatiotemporal variables where a score ≥100 indicates a similar level of gait variability as the control group, and lower scores denote increased gait variability. The study aim was to explore mean GVI score and investigate construct validity of the index for individuals with mild to moderate PD. 100 (57 males) subjects with idiopathic PD, Hoehn & Yahr 2 (n=44) and 3, and ≥60 years were included. Data on disease severity, dynamic balance, mobility and spatiotemporal gait parameters at self-selected speed (GAITRite) was collected. The results showed a mean overall GVI: 97.5 (SD 11.7) and mean GVI for the most affected side: 94.5 (SD 10.6). The associations between the GVI and Mini- BESTest and TUG were low (r=0.33 and 0.42) and the GVI could not distinguish between Hoehn & Yahr 2 and 3 (AUC=0.529, SE=0.058, p=0.622). The mean GVI was similar to previously reported values for older adults, contrary to consistent reports of increased gait variability in PD compared to healthy peers. Therefore, the validity of the GVI could not be confirmed for individuals with mild to moderate PD in its current form due to low associations with validated tests for functional balance and mobility and poor discriminatory ability. Future work should aim to establish which spatiotemporal variables are most informative regarding gait variability in individuals with PD.

Dual tasking in Parkinson's disease: Cognitive consequences while walking

OBJECTIVE

Cognitive deficits are common in Parkinson's disease (PD) and exacerbate the functional limitations imposed by PD's hallmark motor symptoms, including impairments in walking. Though much research has addressed the effect of dual cognitive-locomotor tasks on walking, less is known about their effect on cognition. The purpose of this study was to investigate the relation between gait and executive function, with the hypothesis that dual tasking would exacerbate cognitive vulnerabilities in PD as well as being associated with gait disturbances.

METHOD

Nineteen individuals with mild-moderate PD without dementia and 13 age- and education-matched normal control adults (NC) participated. Executive function (set-shifting) and walking were assessed singly and during dual tasking.

RESULTS

Dual tasking had a significant effect on cognition (reduced set-shifting) and on walking (speed, stride length) for both PD and NC, and also on stride frequency for PD only. The impact of dual tasking on walking speed and stride frequency was significantly greater for PD than NC. Though the group by condition interaction was not significant, PD had fewer set-shifts than NC on dual task. Further, relative to NC, PD showed significantly greater variability in cognitive performance under dual tasking, whereas variability in motor performance remained unaffected by dual tasking.

CONCLUSIONS

Dual tasking had a significantly greater effect in PD than in NC on cognition as well as on walking. The results suggest that assessment and treatment of PD should consider the cognitive as well as the gait components of PD-related deficits under dual-task conditions. (PsycINFO Database Record

Unusual motor and non-motor symptoms and signs in the early stage of Parkinson’s disease

ABSTRACT Objective Patients with Parkinson’s disease (PD) may present with unusual motor and non-motor symptoms and signs in the early stage of the disease. Methods Cases were collected over a five-year period at two tertiary movement disorders clinics. All had a diagnosis of PD with unusual presentations defined retrospectively as the presence of complaints not objectively related to any of the classic cardinal signs of parkinsonism or the typical early non-motor features of PD. Results A total of 15 early PD patients fulfilled the proposed criteria, presenting with symptoms such as atypical tremors, shoulder pain, signs related to the rigid akinetic syndrome, as well as cases of asthenia, rhinorrhea, parosmia, dysgeusia, nocturnal sialorrhea, and color discrimination disorders. Conclusions Unusual motor and non-motor symptoms and signs in the early stage of PD can be difficult to interpret. Specialists should be aware of these conditions as clues to a potential diagnosis.

Freezing of Gait in Parkinson's Disease Is Associated with Reduced 6-[(18)F]Fluoro-l-m-tyrosine Uptake in the Locus Coeruleus

Freezing of gait (FOG) is a common disorder in Parkinson's disease (PD) and could be attributed to a reduction in brain noradrenaline. The aim of this study was to determine the relationship between aromatic l-amino acid decarboxylase (AADC) activity in the locus coeruleus (LC) and FOG in PD using high-resolution positron emission tomography with an AADC tracer, 6-[¹⁸F]fluoro-l-m-tyrosine (FMT). We assessed 40 patients with PD and 11 age-matched healthy individuals. PD was diagnosed based on the UK Brain Bank criteria by two movement disorder experts. FOG was directly observed by the clinician and assessed using a patient questionnaire. FMT uptake in the LC, caudate, and putamen was analyzed using PMOD software on coregistered magnetic resonance images. FOG was present in 30 patients. The severity of FOG correlated with the decrease of FMT uptake in the LC regardless of disease duration and the severity of other motor impairments, indicating dysfunction of the noradrenergic network in FOG.

Focal Muscle Vibration Improves Gait in Parkinson's Disease: A Pilot Randomized, Controlled Trial

Background

In Parkinson's disease (PD), gait disorders lead to increased risk of falls and patients' reduced participation and independence. Several observations suggest that a single session of focal muscle vibration (fMV) applied to trunk or lower limb muscles during gait may improve several gait variables in patients with PD. The possible long-term beneficial effects of repetitive sessions of fMV (r-fMV) on gait of patients with PD have been investigated.

Methods

A randomized, controlled trial study has been conducted in an outpatient rehabilitation department. Twenty patients with PD diagnosis have been randomized in two groups: "real" or "sham" r-fMV application to quadriceps and paraspinal muscles in patients with PD. Gait was evaluated with objective gait analysis, and a number of variables, including velocity, step length, stride length, percentage of stance, double support duration, cadence, swing velocity, and step width, have been measured. Gait analysis was performed before and 24 hours and 1 and 3 weeks after r-fMV.

Results

After real, but not sham, r-fMV, patients with PD had significant gait improvement as a result of increased walking velocity and stride length. The r-fMV-induced beneficial after effects lasted at least 1 week after the end of stimulation.

Conclusions

Data emerging from our pilot randomized, controlled trial study suggest that r-fMV may improve gait disorders in patients with PD. r-fMV might be a feasible, safe approach for possibly improving gait disorders in patients with PD and might enhance the impact of specific rehabilitation programs in PD.

[Mapping Nursing language terms of Parkinson's disease]

OBJECTIVE

Implementing cross-mapping of Nursing language terms with the terminology of NANDA International, contained in records of patients with Parkinson's disease in rehabilitation.

METHOD

Descriptive study of cross mapping, carried out in three steps. A simple random sample of 67 files of patients who participated in the rehabilitation in the period between March 2009 and April 2013.

RESULTS

We identified 454 terms of Nursing language that resulted in 54 diagnoses after cross-mapping, present in 11 of the 13 taxonomy domains. The most mapped diagnosis was "Impaired urinary elimination" (59.7%), followed by "Urgent urinary incontinence" (55.2%), "Willingness to self-control improved health" (50.7%), "Constipation" (47.8%) and "Compromised physical mobility" (29.9%). Seven described terms were not mapped due to a corresponding defining characteristic being absent.

CONCLUSION

It was possible to determine the profile of patients, as well as the complexity of nursing care in the rehabilitation of patients with Parkinson's disease.