Beneficial effect of levodopa therapy on stooped posture in Parkinson's disease

Treatment of axial postural abnormalities in parkinsonism disorders: A systematic review of pharmacological, rehabilitative and surgical interventions

Axial postural abnormalities (PA) are frequent, highly disabling, and drug-refractory motor complications affecting patients with Parkinson's disease (PD) or atypical parkinsonism. Over the past few years, advances have been reached across diagnosis, assessment, and pathophysiological mechanisms of PA. Nonetheless, their management remains a challenge, and these disturbances are generally overlooked by healthcare professionals, potentially resulting in their worsening and impact on patients' disabilities. From shared consensus-based assessment and diagnostic criteria, PA calls for interdisciplinary management based on the complexity and multifactorial pathogenesis. In this context, we conducted a systematic literature review to analyze the available pharmacological and non-pharmacological treatment options for PA in PD according to the new expert-based classification of axial PA in Parkinsonism. Different multidisciplinary approaches, including dopaminergic therapy adjustment, physiotherapy, botulinum toxin injection, and deep brain stimulation, can improve PA depending on its type and severity. An early, interdisciplinary approach is recommended in PD patients to manage PA.

Alteration of Postural Reactions in Rats with Different Levels of Dopamine Depletion

Dopamine (DA) is the critical neurotransmitter involved in the unconscious control of muscle tone and body posture. We evaluated the general motor capacities and muscle responses to postural disturbance in three conditions: normal DA level (wild-type rats, WT), mild DA deficiency (WT after administration of α-methyl-p-tyrosine-AMPT, that blocks DA synthesis), and severe DA depletion (DAT-KO rats after AMPT). The horizontal displacements in WT rats elicited a multi-component EMG corrective response in the flexor and extensor muscles. Similar to the gradual progression of DA-related diseases, we observed different degrees of bradykinesia, rigidity, and postural instability after AMPT. The mild DA deficiency impaired the initiation pattern of corrective responses, specifically delaying the extensor muscles' activity ipsilaterally to displacement direction and earlier extensor activity from the opposite side. DA depletion in DAT-KO rats after AMPT elicited tremors, general stiffness, and akinesia, and caused earlier response to horizontal displacements in the coactivated flexor and extensor muscles bilaterally. The data obtained show the specific role of DA in postural reactions and suggest that this experimental approach can be used to investigate sensorimotor control in different dopamine-deficient states and to model DA-related diseases.

Staying UpRight in Parkinson's disease: A pilot study of a novel wearable postural intervention

OBJECTIVES

This interventional pilot study aimed to 1) examine whether a novel wearable vibro-tactile feedback device ('UpRight Go') is effective and feasible to improve postural alignment in Parkinson's disease (PD); 2) explore relationships between postural alignment and attention in PD; 3) explore effect of vibro-tactile device on balance and gait; and 4) gain initial feedback on the use of the vibro-tactile device in the laboratory and at home.

METHODS

25 people with PD sat, stood and walked for two-minutes without and with the UpRight device attached to their upper backs to provide feedback on postural alignment in the laboratory. A sub-group (n = 12) wore the UpRight device at home for 60 min. per day for 7-days of postural feedback. Subjective feedback on use of the device was obtained in the laboratory and at the end of the 7-day period. The primary outcome for this study was posture measured by verticality of inertial measurement units (IMUs) at the neck, trunk and low back, which was done with and without the UpRight device. Secondary outcomes included clinical measures of posture, subjective feedback on the device, computerized attention measures, gait and balance.

RESULTS

Neck postural alignment in PD was significantly improved (reduced neck flexion) with the UpRight during sitting and standing in both clinical measures (p = 0.005) and IMU outcomes (p = 0.046), but trunk and low back posture did not change. There was no change in postural alignment during walking with the UpRight. Postural alignment response was related to attentional capabilities. Many subjects (68 %) reported that they felt a benefit from the UpRight and most participants reported that the device was acceptable (Lab use; 72 %, Home use; 75 %).

CONCLUSION

The UpRight Go feedback device may improve neck/upper-back posture in PD during sitting and standing, but not during walking. Postural alignment response to the device may depend on attentional mechanisms.

Temporal dynamics of cortical activity and postural control in response to the first levodopa dose of the day in people with Parkinson's disease

BACKGROUND

Our understanding of how balance control responds to levodopa over the course of a single day in people with Parkinson's disease (PD) is limited with the majority of studies focused on isolated comparisons of ON vs. OFF levodopa medication.

OBJECTIVE

To evaluate the temporal dynamics of postural control following the first levodopa dose of the day during a challenging standing task in a group of people with PD.

METHODS

Changes in postural control were evaluated by monitoring cortical activity (covering frontal, motor, parietal and occipital areas), body sway parameters (force platform), and lower limb muscle activity (tibialis anterior and gastrocnemius medialis) in 15 individuals with PD during a semi-tandem standing task. Participants were assessed during two 60 second trials every 30 minutes (ON-30 ON-60 etc.) for 3 hours after the first matinal dose (ON-180).

RESULTS

Compared to when tested OFF-medication, cortical activity was increased across all four regions from ON-60 to ON-120 with early increases in alpha and beta band activity observed at ON-30. Levodopa was associated with increased gastrocnemius medialis activity (ON-30 to ON-120) and ankle co-contraction (ON-60 to ON-120). Changes in body sway outcomes (particularly in the anterior-posterior direction) were evident from ON-60 to ON-120.

CONCLUSIONS

Our results reveal a 60-minute window within which postural control outcomes may be obtained that are different compared to OFF-state and remain stable (from 60-minutes to 120-minutes after levodopa intake). Identifying a window of opportunity for measurement when individuals are optimally medicated is important for observations in a clinical and research setting.

Measurement and Correction of Stooped Posture during Gait Using Wearable Sensors in Patients with Parkinsonism: A Preliminary Study

Stooped posture, which is usually aggravated during walking, is one of the typical postural deformities in patients with parkinsonism. However, the degree of stooped posture is difficult to quantitatively measure during walking. Furthermore, continuous feedback on posture is also difficult to provide. The purpose of this study is to measure the degree of stooped posture during gait and to investigate whether vibration feedback from sensor modules can improve a patient's posture. Parkinsonian patients with stooped posture were recruited for this study. Two wearable sensors with three-axis accelerometers were attached, one at the upper neck and the other just below the C7 spinous process of the patients. After being calibrated in the most upright posture, the sensors continuously recorded the sagittal angles at 20 Hz and averaged the data at every second during a 6 min walk test. In the control session, the patients walked with the sensors as usual. In the vibration session, sensory feedback was provided through vibrations from the neck sensor module when the sagittal angle exceeded a programmable threshold value. Data were collected and analyzed successfully in a total of 10 patients. The neck flexion and back flexion were slightly aggravated during gait, although the average change was <10° in most patients in both measurement sessions. Therefore, it was difficult to evaluate the effect of sensory feedback through vibration. However, some patients showed immediate response to the feedback and corrected their posture during gait. In conclusion, this preliminary study suggests that stooped posture could be quantitatively measured during gait by using wearable sensors in patients with parkinsonism. Sensory feedback through vibration from sensor modules may help in correcting posture during gait in selected patients.

Cueing Paradigms to Improve Gait and Posture in Parkinson's Disease: A Narrative Review

Progressive gait dysfunction is one of the primary motor symptoms in people with Parkinson’s disease (PD). It is generally expressed as reduced step length and gait speed and as increased variability in step time and step length. People with PD also exhibit stooped posture which disrupts gait and impedes social interaction. The gait and posture impairments are usually resistant to the pharmacological treatment, worsen as the disease progresses, increase the likelihood of falls, and result in higher rates of hospitalization and mortality. These impairments may be caused by perceptual deficiencies (poor spatial awareness and loss of temporal rhythmicity) due to the disruptions in processing intrinsic information related to movement initiation and execution which can result in misperceptions of the actual effort required to perform a desired movement and maintain a stable posture. Consequently, people with PD often depend on external cues during execution of motor tasks. Numerous studies involving open-loop cues have shown improvements in gait and freezing of gait (FoG) in people with PD. However, the benefits of cueing may be limited, since cues are provided in a consistent/rhythmic manner irrespective of how well a person follows them. This limitation can be addressed by providing feedback in real-time to the user about performance (closed-loop cueing) which may help to improve movement patterns. Some studies that used closed-loop cueing observed improvements in gait and posture in PD, but the treadmill-based setup in a laboratory would not be accessible outside of a research setting, and the skills learned may not readily and completely transfer to overground locomotion in the community. Technologies suitable for cueing outside of laboratory environments could facilitate movement practice during daily activities at home or in the community and could strongly reinforce movement patterns and improve clinical outcomes. This narrative review presents an overview of cueing paradigms that have been utilized to improve gait and posture in people with PD and recommends development of closed-loop wearable systems that can be used at home or in the community to improve gait and posture in PD.

Postural Abnormality in Parkinson's Disease: A Large Comparative Study With General Population

Background

Postural abnormalities in Parkinson's disease (PD) patients and unimpaired elderly are not well differentiated. Factors related to postural abnormality associated with PD are controversial.

Objective

We assessed differences in postural change between PD patients and unimpaired elderly and elucidated factors related to abnormal posture in PD patients.

Methods

We measured the dropped head angle (DHA), anterior flexion angle (AFA), and lateral flexion angle (LFA) of the thoracolumbar spine of an unprecedented 1,117 PD patients and 2,732 general population participants (GPPs) using digital photographs. Two statistical analyses were used for elucidating factors related to these angles.

Results

In GPPs, age was correlated with DHA, AFA, and LFA. DHAs, AFAs, and LFAs of PD patients and age-matched GPPs were 21.70° ± 14.40° and 13.13° ± 10.79°, 5.98° ± 12.67,°and - 3.82° ± 4.04°, and 0.86° ± 4.25° and 1.33° ± 2.16°, respectively. In PD patients, factors related to DHA were age, male sex, and H & Y stage during ON time. Factors related to AFA were age, duration of disease, H & Y stage during ON and OFF times, pain, vertebral disease, and bending to the right. A factor related to LFA was AFA.

Conclusions

DHA and AFA of GGPs correlated with age and were larger in PD patients than those with in GPPs. Some PD patients showed angles far beyond the normal distribution. Thus, factors associated with disease aggravation affected postural abnormality in PD patients.

Gait festination in parkinsonism: introduction of two phenotypes

Gait festination is one of the most characteristic gait disturbances in patients with Parkinson’s disease or atypical parkinsonism. Although festination is common and disabling, it has received little attention in the literature, and different definitions exist. Here, we argue that there are actually two phenotypes of festination. The first phenotype entails a primary locomotion disturbance, due to the so-called sequence effect: a progressive shortening of step length, accompanied by a compensatory increase in cadence. This phenotype strongly relates to freezing of gait with alternating trembling of the leg. The second phenotype results from a postural control problem (forward leaning of the trunk) combined with a balance control deficit (inappropriately small balance-correcting steps). In this viewpoint, we elaborate on the possible pathophysiological substrate of these two phenotypes of festination and discuss their management in daily clinical practice.

Evaluation of smartphone-based testing to generate exploratory outcome measures in a phase 1 Parkinson's disease clinical trial

BACKGROUND

Ubiquitous digital technologies such as smartphone sensors promise to fundamentally change biomedical research and treatment monitoring in neurological diseases such as PD, creating a new domain of digital biomarkers.

OBJECTIVES

The present study assessed the feasibility, reliability, and validity of smartphone-based digital biomarkers of PD in a clinical trial setting.

METHODS

During a 6-month, phase 1b clinical trial with 44 Parkinson participants, and an independent, 45-day study in 35 age-matched healthy controls, participants completed six daily motor active tests (sustained phonation, rest tremor, postural tremor, finger-tapping, balance, and gait), then carried the smartphone during the day (passive monitoring), enabling assessment of, for example, time spent walking and sit-to-stand transitions by gyroscopic and accelerometer data.

RESULTS

Adherence was acceptable: Patients completed active testing on average 3.5 of 7 times/week. Sensor-based features showed moderate-to-excellent test-retest reliability (average intraclass correlation coefficient = 0.84). All active and passive features significantly differentiated PD from controls with P < 0.005. All active test features except sustained phonation were significantly related to corresponding International Parkinson and Movement Disorder Society-Sponsored UPRDS clinical severity ratings. On passive monitoring, time spent walking had a significant (P = 0.005) relationship with average postural instability and gait disturbance scores. Of note, for all smartphone active and passive features except postural tremor, the monitoring procedure detected abnormalities even in those Parkinson participants scored as having no signs in the corresponding International Parkinson and Movement Disorder Society-Sponsored UPRDS items at the site visit.

CONCLUSIONS

These findings demonstrate the feasibility of smartphone-based digital biomarkers and indicate that smartphone-sensor technologies provide reliable, valid, clinically meaningful, and highly sensitive phenotypic data in Parkinson's disease. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Sensor assisted self-management in Parkinson's disease: A feasibility study of ambulatory posture detection and feedback to treat stooped posture

INTRODUCTION

A stooped posture is one of the characteristic motor symptoms of patients with Parkinson's disease, and has been linked to impairments in daily activities and quality of life. We aimed to test the efficacy, safety, practical utility and user-friendliness of a posture correction and vibrotactile trunk angle feedback device (the UpRight) in the home setting of patients with Parkinson's disease with a stooped posture. It was hypothesized that ambulatory use of the UpRight would be safe, feasible and result in a less stooped posture, i.e. a lower trunk angle during daily activities.

METHODS

15 patients wore the UpRight during a baseline period of 1 week (no feedback), followed by an intervention period of 1 week (feedback).

RESULTS

We found a significant decrease (average -5,4°) in trunk angle from baseline period to intervention period without the occurrence of adverse events. In addition, patients found the device usable and beneficial to posture.

CONCLUSION

Use of the feedback and correction device has a positive effect on ambulatory trunk angles. The device appears to be both safe and useful for self-management of stooped posture in patients with Parkinson's Disease.

Forward flexion of trunk in Parkinson's disease patients is affected by subjective vertical position

PURPOSE

No method has been established to evaluate the dissociation between subjective and objective vertical positions with respect to the self-awareness of postural deformity in patients with Parkinson's disease (PD). The purpose of this study was to demonstrate, from the relationship between an assessment of the dissociation of subjective and objective vertical positions of PD patients and an assessment based on established PD clinical evaluation scales, that the dissociation regarding vertical position is a factor in the severity of the forward flexion of trunk (FFT).

METHODS

Subjects were 39 PD patients and 15 age-matched healthy individuals (control group). Posture was evaluated with measurement of FFT angle during static standing and the subjective vertical position (SV) of the patient. For evaluation of motor function, the Modified Hoehn & Yahr scale, Unified Parkinson's Disease Rating Scale (UPDRS), 3-m Timed Up and Go Test (TUG), and Functional Reach Test (FRT) were used.

RESULTS

In PD patients, FFT angle in the 3rd tertile of patients was 13.8±9.7°, significantly greater than those in the control group and the 1st and 2nd tertiles of PD patients (control group vs 3rd tertile, p = 0.008; 1st tertile vs 3rd tertile, p<0.001; 2nd vs 3rd tertile, p = 0.008). In multiple regression analysis for factors in the FFT angle, significant factors were SV, disease duration, and the standard deviation of each SV angle measurement.

CONCLUSION

The dissociation between SV and objective vertical position affects the FFT of PD patients, suggesting an involvement of non-basal ganglia pathologies.

Mobility and Upright Posture Are Associated with Different Aspects of Cognition in Older Adults

Objectives: Aging is associated with cognitive decline, including visuomotor and memory concerns, and with motor system changes, including gait slowing and stooped posture. We investigated the associations of visuomotor performance and episodic memory with motor system characteristics in healthy older adults. Methods: Neurologically healthy older adults (N = 160, aged 50-89) completed a battery of cognitive and motor tasks. Cognitive variables were grouped by principal components analysis (PCA) into two components: visuomotor performance and verbal episodic memory. Our primary predictor variables were two aspects of motor function: timed-up-and-go (TUG) speed and neck angle. Additional predictor variables included demographic factors (age, sex and education) and indicators of physical fitness (body mass index/BMI and grip strength). All seven predictor variables were entered stepwise into a multiple regression model for each cognitive component. Results: Poor visuomotor performance was best predicted by a combination of advanced age, high BMI and slow TUG, whereas poor verbal memory performance was best predicted by a combination of advanced age, male sex, low education and acute neck angle. Conclusions: Upright posture and mobility were associated with different cognitive processes, suggesting different underlying neural mechanisms. These results provide the first evidence for a link between postural alignment and cognitive functioning in healthy older adults. Possible causal relationships are discussed.