Pisa syndrome in Parkinson's disease: An integrated approach from pathophysiology to management

Incidence and predictors of postural abnormalities in Parkinson's disease: a PPMI cohort study

BACKGROUND

Axial postural abnormalities (PA) are invalidating symptoms of Parkinson's disease (PD). Risk factors for PA are unknown.

OBJECTIVES

We sought to evaluate PA incidence and risk factors over the first 4-6 years of PD.

METHODS

We included 441 PD patients from the Parkinson's Progression Markers Initiative (PPMI) cohort with data at diagnosis and after 4-year follow-up. PA was defined according to a posture item ≥ 2 at the Movement Disorder Society-sponsored-revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) in Off therapeutic condition. The Kruskal-Wallis test was used to compare characteristics of patients without PA ('no-PA'), with PA at disease onset ('baseline-PA'), and PA developed during follow-up ('develop-PA'). To identify predictors of PA development, univariate and multivariate Cox regression analyses were performed considering demographic, clinical and therapeutic variables.

RESULTS

10.9% of patients showed PA at baseline and 23.7% developed PA within the first 4-6 years since diagnosis. Older age, malignant phenotype, higher MDS-UPDRS part III, Hoehn & Yahr, and dysautonomia (SCOPA-AUT) score, and lower levels of physical activity were predictors of PA development at the univariate analysis. Older age (Hazard ratio [HR] per year: 1.041) and higher MDS-UPDRS part III score (HR per point: 1.035) survived as PA development predictors in the multivariate analysis.

CONCLUSIONS

PPMI cohort data show that > 30% of PD patients present PA within the first 4-6 years of disease. Older age at onset and higher motor burden are associated with a higher risk for PA development. The protective role of physical activity merits to be further investigated.

Hypoperfusion in Supramarginal and Orbital Gyrus, Position Discrimination Test, and Microsaccades as a Predictor of Pisa Syndrome in Parkinson's Disease

Patients with Parkinson's disease (PD) experience significantly reduced quality of life when PD is complicated with Pisa syndrome (PS). PS is a postural abnormality associated with a lateral bending of the trunk, causing the patient to lean to one side. Microsaccades during fixation are transmitted to the visual cortex, and this gaze movement may be impaired in PD. We aimed to detect presymptomatic signs of PS. We enrolled 50 patients with PD without dementia and investigated the visual systems in patients with concurrent PD and PS based on a Romberg ratio of<1.0. Gaze analysis, pupil diameter, stabilization tests, neuropsychological tests, and cerebral perfusion scintigraphy were reviewed and statistically analyzed. Two years later, we divided the patients into three groups as follows: PISA++ (patients who had PS at enrollment), PISA-+ (patients without PS that developed PS during the 2-year period), and PISA-- (patients without PS that did not develop PS during the 2-year period). The PISA-+ group exhibited a significantly higher daily levodopa dose and longer fixations, as well as lower position discrimination, Wechsler Adult Intelligence Scale-Third Edition blocking, and blood flow in the left supramarginal and orbital gyri than that in the PISA-- group. The PISA++ group showed a significantly longer fixation time and lower Mini-Mental State Examination score, Romberg ratio of area, amplitude, velocity of microsaccades, and blood flow in the left precuneus and cuneus than that in the PISA-+ group. Before the onset of PS, hypoperfusion occurred in the correlative visual cortex and the position discrimination test. Patients with PS have reduced saccades and slow microsaccades.

Vestibular dysfunction in Parkinson's disease: a neglected topic

Dizziness and postural instability are frequently observed symptoms in patient with Parkinson's disease (PD), potentially linked to vestibular dysfunction. Despite their significant impact on quality of life, these symptoms are often overlooked and undertreated in clinical practice. This review aims to summarize symptoms associated with vestibular dysfunction in patients with PD and discusses vestibular-targeted therapies for managing non-specific dizziness and related symptoms. We conducted searches in PubMed and Web of Science using keywords related to vestibular dysfunction, Parkinson's disease, dizziness, and postural instability, alongside the reference lists of relevant articles. The available evidence suggests the prevalence of vestibular dysfunction-related symptoms in patients with PD and supports the idea that vestibular-targeted therapies may be effective in improving PD symptoms.

Camera- and Viewpoint-Agnostic Evaluation of Axial Postural Abnormalities in People with Parkinson's Disease through Augmented Human Pose Estimation

Axial postural abnormalities (aPA) are common features of Parkinson's disease (PD) and manifest in over 20% of patients during the course of the disease. aPA form a spectrum of functional trunk misalignment, ranging from a typical Parkinsonian stooped posture to progressively greater degrees of spine deviation. Current research has not yet led to a sufficient understanding of pathophysiology and management of aPA in PD, partially due to lack of agreement on validated, user-friendly, automatic tools for measuring and analysing the differences in the degree of aPA, according to patients' therapeutic conditions and tasks. In this context, human pose estimation (HPE) software based on deep learning could be a valid support as it automatically extrapolates spatial coordinates of the human skeleton keypoints from images or videos. Nevertheless, standard HPE platforms have two limitations that prevent their adoption in such a clinical practice. First, standard HPE keypoints are inconsistent with the keypoints needed to assess aPA (degrees and fulcrum). Second, aPA assessment either requires advanced RGB-D sensors or, when based on the processing of RGB images, they are most likely sensitive to the adopted camera and to the scene (e.g., sensor-subject distance, lighting, background-subject clothing contrast). This article presents a software that augments the human skeleton extrapolated by state-of-the-art HPE software from RGB pictures with exact bone points for posture evaluation through computer vision post-processing primitives. This article shows the software robustness and accuracy on the processing of 76 RGB images with different resolutions and sensor-subject distances from 55 PD patients with different degrees of anterior and lateral trunk flexion.

How resistant are levodopa-resistant axial symptoms? Response of freezing, posture, and voice to increasing levodopa intestinal infusion rates in Parkinson disease

BACKGROUND AND PURPOSE

Treatment of freezing of gait (FoG) and other Parkinson disease (PD) axial symptoms is challenging. Systematic assessments of axial symptoms at progressively increasing levodopa doses are lacking. We sought to analyze the resistance to high levodopa doses of FoG, posture, speech, and altered gait features presenting in daily-ON therapeutic condition.

METHODS

We performed a pre-/postinterventional study including patients treated with levodopa/carbidopa intestinal gel infusion (LCIG) with disabling FoG in daily-ON condition. Patients were evaluated at their usual LCIG infusion rate (T1), and 1 h after 1.5× (T2) and 2× (T3) increase of the LCIG infusion rate by quantitative outcome measures. The number of FoG episodes (primary outcome), posture, speech, and gait features were objectively quantified during a standardized test by a blinded rater. Changes in motor symptoms, dyskinesia, and plasma levodopa concentrations were also analyzed.

RESULTS

We evaluated 16 patients with a mean age of 69 ± 9.4 years and treated with LCIG for a mean of 2.2 ± 2.1 years. FoG improved in 83.3% of patients by increasing the levodopa doses. The number of FoG episodes significantly decreased (mean = 2.3 at T1, 1.7 at T2, 1.2 at T3; p = 0.013). Posture and speech features did not show significant changes, whereas stride length (p = 0.049), turn duration (p = 0.001), and turn velocity (p = 0.024) significantly improved on doubling the levodopa infusion rate.

CONCLUSIONS

In a short-term evaluation, the increase of LCIG dose can improve "dopa-resistant" FoG and gait issues in most advanced PD patients with overall good control of motor symptoms in the absence of clinically significant dyskinesia.

A summary index derived from Kinect to evaluate postural abnormalities severity in Parkinson’s Disease patients

Postural abnormalities are common disabling motor complications affecting patients with Parkinson’s disease (PD). We proposed a summary index for postural abnormalities (IPA) based on Kinect depth camera and explored the clinical value of this indicator. Seventy individuals with PD and thirty age-matched healthy controls (HCs) were enrolled. All participants were tested using a Kinect-based system with IPA automatically obtained by algorithms. Significant correlations were detected between IPA and the Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) total score (rs = 0.369, p = 0.002), MDS-UPDRS-III total score (rs = 0.431, p < 0.001), MDS-UPDRS-III 3.13 score (rs = 0.573, p < 0.001), MDS-UPDRS-III-bradykinesia score (rs = 0.311, p = 0.010), the 39-item Parkinson’s Disease Questionnaire (PDQ-39) (rs = 0.272, p = 0.0027) and the Berg Balance Scale (BBS) score (rs = −0.350, p = 0.006). The optimal cut-off value of IPA for distinguishing PD from HCs was 12.96 with a sensitivity of 97.14%, specificity of 100.00%, area under the curve (AUC) of 0.999 (0.997–1.002, p < 0.001), and adjusted AUC of 0.998 (0.993–1.000, p < 0.001). The optimal cut-off value of IPA for distinguishing between PD with and without postural abnormalities was 20.14 with a sensitivity, specificity, AUC and adjusted AUC of 77.78%, 73.53%, 0.817 (0.720–0.914, p < 0.001), and 0.783 (0.631–0.900, p < 0.001), respectively. IPA was significantly correlated to the clinical manifestations of PD patients, and could reflect the global severity of postural abnormalities in PD with important value in distinguishing PD from HCs and distinguishing PD with postural abnormalities from those without.

Axial posture disorders in Parkinson's disease: Clinical correlates and future treatment directions1

BACKGROUND

Postural disorders are frequently observed in Parkinson's disease (PD). The underlying mechanisms that cause postural disorders are not fully understood and the majority of these disorders have no response to antiparkinsonian treatments. These disabling conditions require further investigation to better understand the underlying mechanisms in order to develop effective treatments.

OBJECTIVE

The aim of this study was to investigate the frequency of axial postural disorders in PD and to determine the associated clinical risk factors.

METHODS

In this single-center clinical trial, the data of PD patients were reviewed retrospectively. The frequencies of postural disorders were determined, and the demographic clinical characteristics of the patients were compared.

RESULTS

The records of 127 patients with idiopathic PD were analyzed. Axial posture disorders were found in 42.6% of patients. Patients with axial posture disorders were older when the disease onset was detected, amongst these patients the condition was also longer lasting. The mean levodopa dose was higher in the patients with posture disorders. The initial symptom was bradykinesia and the Hoehn and Yahr's score was ⩾ 3 in the majority of the patients with posture disorder. Additionally, constipation, hallucinations, postural instability, and falls were significantly more common in patients with posture disorders.

CONCLUSION

Posture disorders were observed in nearly half of PD patients and were more frequently observed in patients with an advanced condition. In addition, our investigation has found that it is crucial to follow up with patients who present with bradykinesia for the development of postural disorder.

Reversible Pisa syndrome caused by chronic subdural hematoma in a patient with Parkinson’s disease: a case report

Background

Pisa syndrome (PS), characterized by lateral trunk flexion, is quite common in patients with Parkinson’s disease (PD). Patients with PS are older and have a significantly longer disease duration, more severe motor phenotype, ongoing combined treatment with levodopa and dopamine agonists, and higher levodopa equivalent daily dose. We describe here, to the best of our knowledge, the first case of a woman with PD who developed acute-onset PS caused by chronic subdural hematoma (CSDH).

Case presentation

A 70-year-old woman developed acute-onset lateral flexion of her trunk to the left side while standing, and she was admitted to our hospital. One month before, she had a mild head trauma with loss of consciousness. At 65 years of age, she noticed difficulty with walking and clumsiness with her hands. She was diagnosed as having PD (Hoehn and Yahr stage 2) and levodopa was initiated. Her symptoms were markedly improved. At 67 years of age, she developed orthostatic hypotension and was treated sequentially with fluids, compression stockings, and midodrine. Urgently performed brain computed tomography (CT) showed a CSDH in the right hemisphere resulting in a marked compression of the hemisphere. After surgical evacuation, her PS disappeared. She has fully recovered to her preoperative level of function.

Conclusion

The present case provides a valuable insight, that is, the mesial frontal lobe and its connections from the posterior parietal cortex play crucial roles in maintaining the body schema and in the pathophysiology of PS. This case suggests that CSDH should be considered when clinicians examine acute-onset PS, even in patients with neurodegenerative disorders such as PD. Appropriate patient triage and timely neurosurgical intervention should be considered.

Pathological characterization of a novel mouse model expressing the PD-linked CHCHD2-T61I mutation

Coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2) is a mitochondrial protein that plays important roles in cristae structure, oxidative phosphorylation and apoptosis. Multiple mutations in CHCHD2 have been associated with Lewy body disorders (LBDs), such as Parkinson's disease (PD) and dementia with Lewy bodies, with the CHCHD2-T61I mutation being the most widely studied. However, at present, only CHCHD2 knockout or CHCHD2/CHCHD10 double knockout mouse models have been investigated. They do not recapitulate the pathology seen in patients with CHCHD2 mutations. We generated the first transgenic mouse model expressing the human PD-linked CHCHD2-T61I mutation driven by the mPrP promoter. We show that CHCHD2-T61I Tg mice exhibit perinuclear mitochondrial aggregates, neuroinflammation, and have impaired long-term synaptic plasticity associated with synaptic dysfunction. Dopaminergic neurodegeneration, a hallmark of PD, is also observed along with α-synuclein pathology. Significant motor dysfunction is seen with no changes in learning and memory at 1 year of age. A minor proportion of the CHCHD2-T61I Tg mice (~10%) show a severe motor phenotype consistent with human Pisa Syndrome, an atypical PD phenotype. Unbiased proteomics analysis reveals surprising increases in many insoluble proteins predominantly originating from mitochondria and perturbing multiple canonical biological pathways as assessed by ingenuity pathway analysis, including neurodegenerative disease-associated proteins such as tau, cofilin, SOD1 and DJ-1. Overall, CHCHD2-T61I Tg mice exhibit pathological and motor changes associated with LBDs, indicating that this model successfully captures phenotypes seen in human LBD patients with CHCHD2 mutations and demonstrates changes in neurodegenerative disease-associated proteins, which delineates relevant pathological pathways for further investigation.

Task force consensus on nosology and Cut‐Off values for axial postural abnormalities in parkinsonism

Background

There is no consensus with regard to the nosology and cut‐off values for postural abnormalities in parkinsonism.

Objective

To reach a consensus regarding the nosology and cut‐off values.

Methods

Using a modified Delphi panel method, multiple rounds of questionnaires were conducted by movement disorder experts to define nosology and cut‐offs of postural abnormalities.

Results

After separating axial from appendicular postural deformities, a full agreement was found for the following terms and cut‐offs: camptocormia, with thoracic fulcrum (>45°) or lumbar fulcrum (>30°), Pisa syndrome (>10°), and antecollis (>45°). “Anterior trunk flexion,” with thoracic (≥25° to ≤45°) or lumbar fulcrum (>15° to ≤30°), “lateral trunk flexion” (≥5° to ≤10°), and “anterior neck flexion” (>35° to ≤45°) were chosen for milder postural abnormalities.

Conclusions

For axial postural abnormalities, we recommend the use of proposed cut‐offs and six unique terms, namely camptocormia, Pisa syndrome, antecollis, anterior trunk flexion, lateral trunk flexion, anterior neck flexion, to harmonize clinical practice and future research.

Benefits of Virtual Reality Balance Training for Patients With Parkinson Disease: Systematic Review, Meta-analysis, and Meta-Regression of a Randomized Controlled Trial

BACKGROUND

Virtual reality (VR) balance training is increasingly being pursued in biomedical research, specifically with respect to investigating balance ability with VR. However, existing systematic reviews have found inconsistent conclusions about the efficacy of VR in improving balance in Parkinson disease (PD) patients.

OBJECTIVE

The goal of the research was to evaluate the impact of VR balance training on the balance ability of patients with PD.

METHODS

All major databases, including Web of Science, PubMed, Scopus, China National Knowledge Infrastructure, and Wanfang, were searched to identify all relevant studies published in English or Chinese since September 15, 2010. Two researchers independently conducted document retrieval, study selection, data extraction, and methodological quality evaluation.

RESULTS

A total of 16 randomized controlled trials were analyzed (n=583 patients with PD), with the methodological quality evaluation score ranging from 5 to 8 points. A random effects model was selected to combine effect sizes. Meta-analysis showed that the balance ability of PD was significantly improved after VR training compared with the control group (standardized mean difference [SMD] 2.127, 95% CI 1.202 to 3.052, P<.001, I²=95.1, df=15). It is worth noting that the intervention platform may be the main reason for heterogeneity. Meta regression analysis showed that no training program could predict the impact of VR training (P=.57 to .94) on PD balance ability. Subgroup result showed that a single training time of 0 to 20 minutes (SMD 6.446), 4 to 6 times per week (SMD 4.067), training for 3 to 5 weeks (SMD 62.478), training course reached more than 30 times (SMD 4.405), and 201 to 300 minutes per week (SMD 4.059) maybe have more benefit.

CONCLUSIONS

A systematic review and meta-analysis confirmed that VR balance training is a highly effective means to improve balance performance with large effects in PD. In addition, we preliminarily extracted dose-effect relationships for training volume, informing clinicians and practitioners to design effective VR balance training for balance ability. Further research is needed to reveal optimal dose-response relationships following VR balance training.

Automated and accurate assessment for postural abnormalities in patients with Parkinson's disease based on Kinect and machine learning

Background

Automated and accurate assessment for postural abnormalities is necessary to monitor the clinical progress of Parkinson’s disease (PD). The combination of depth camera and machine learning makes this purpose possible.

Methods

Kinect was used to collect the postural images from 70 PD patients. The collected images were processed to extract three-dimensional body joints, which were then converted to two-dimensional body joints to obtain eight quantified coronal and sagittal features (F1-F8) of the trunk. The decision tree classifier was carried out over a data set established by the collected features and the corresponding doctors’ MDS-UPDRS-III 3.13 (the 13th item of the third part of Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale) scores. An objective function was implanted to further improve the human–machine consistency.

Results

The automated grading of postural abnormalities for PD patients was realized with only six selected features. The intraclass correlation coefficient (ICC) between the machine’s and doctors’ score was 0.940 (95%CI, 0.905–0.962), meaning the machine was highly consistent with the doctors’ judgement. Besides, the decision tree classifier performed outstandingly, reaching 90.0% of accuracy, 95.7% of specificity and 89.1% of sensitivity in rating postural severity.

Conclusions

We developed an intelligent evaluation system to provide accurate and automated assessment of trunk postural abnormalities in PD patients. This study demonstrates the practicability of our proposed method in the clinical scenario to help making the medical decision about PD.

Standardized Biomechanical Investigation of Posture and Gait in Pisa Syndrome Disease

Pisa syndrome is one of the possible postural deformities associated with Parkinson’s disease and it is clinically defined as a sustained lateral bending of the trunk. Some previous studies proposed clinical and biomechanical investigation to understand the pathophysiological mechanisms that occur, mainly focusing on EMG patterns and clinics. The current research deals with the assessment of a standardized biomechanical analysis to investigate the Pisa syndrome postural effects. Eight patients participated in the experimental test. Both static posture and gait trials were performed. An optoelectronic system and two force plates were used for data acquisition, while a custom multi-segments kinematic model of the human spine was used to evaluate the 3D angles. All subjects showed an important flexion of the trunk superior segment with respect to the inferior one, with a strong variability among patients (range values between 4.3° and 41.0°). Kinematics, ground reaction forces and spatio-temporal parameters are influenced by the asymmetrical trunk posture. Moreover, different proprioception, compensation and abilities of correction were depicted among subjects. Considering the forces exchanged by the feet with the floor during standing, results highlighted a significant asymmetry (p-value = 0.02) between the omo and contralateral side in a normal static posture, with greater load distribution on the same side of lateral deviation. When asked to self-correct the posture, all patients demonstrated a reduction of asymmetry, but without stressing any statistical significance. All these aspects might be crucial for the definition of a PS patients’ classification and for the assessment of the efficacy of treatments and rehabilitation.

Pisa syndrome: Pathophysiology, physical rehabilitation and falls risk

BACKGROUND

Pisa syndrome (PS) is a postural disorder characterised by lateral flexion of the spine (> 10°), predisposing the affected individuals to falls, and contributing to increased mortality in neurodegenerative diseases.

OBJECTIVE

An overview of currently applied therapeutic management options, primarily focused on specifically structured rehabilitation exercises, in conjunction with falls-risk assessment in the individuals affected by PS.

METHODS

A narrative literature review, augmented with the authors' own experience in physical rehabilitation management.

RESULTS

As individuals affected by PS are evidenced to be intrinsically exposed to higher falls-risk through acquired postural deformities, they often fall victims of traumatic accidents, occasionally also facing relocation into 24-hour nursing facilities due to the injuries sustained/resultant disability, consequently having overall quality of their life appreciably reduced.

CONCLUSIONS

sA comprehensive approach is postulated in designing optimal therapeutic management, comprised of the exercises controlling postural stability, whilst reducing lower back pain, and the ones also promoting specific skills essential for coping unassisted after an accidental fall effectively. Rehabilitation of individuals affected by PS should be a fully integrated service, eliminating all identified risk factors for falls. As clinical PS symptoms tend to recur after completion of a full course of therapeutic management, all PS patients should continue the pursuit of therapeutic exercises on an individual basis, to effectively retard their recurrence. In view of overall scarcity of clinical studies completed on the large population samples of PS patients, further in-depth research is still required to ensure higher credence to overall efficacy of the presently proposed therapeutic solutions.

Contribution of Basal Ganglia to the Sense of Upright: A Double-Blind Within-Person Randomized Trial of Subthalamic Stimulation in Parkinson's Disease with Pisa Syndrome

BACKGROUND

Verticality perception is frequently altered in Parkinson's disease (PD) with Pisa syndrome (PS). Is it the cause or the consequence of the PS?

OBJECTIVE

We tested the hypothesis that both scenarios coexist.

METHODS

We performed a double-blind within-person randomized trial (NCT02704910) in 18 individuals (median age 63.5 years) with PD evolving for a median of 17.5 years and PS for 2.5 years and treated with bilateral stimulation of the subthalamus nuclei (STN-DBS) for 6.5 years. We analyzed whether head and trunk orientations were congruent with the visual (VV) and postural (PV) vertical, and whether switching on one or both sides of the STN-DBS could modulate trunk orientation via verticality representation.

RESULTS

The tilted verticality perception could explain the PS in 6/18 (33%) patients, overall in three right-handers (17%) who showed net and congruent leftward trunk and PV tilts. Two of the 18 (11%) had an outstanding clinical picture associating leftward: predominant parkinsonian symptoms, whole-body tilt (head -11°, trunk -8°) and transmodal tilt in verticality perception (PV -10°, VV -8.9°). Trunk orientation or VV were not modulated by STN-DBS, whereas PV tilts were attenuated by unilateral or bilateral stimulations if it was applied on the opposite STN.

CONCLUSION

In most cases of PS, verticality perception is altered by the body deformity. In some cases, PS seems secondary to a biased internal model of verticality, and DBS on the side of the most denervated STN attenuated PV tilts with a quasi-immediate effect. This is an interesting track for further clinical studies.

Decreased grey matter in the postural control network is associated with lateral flexion of the trunk in Parkinson's disease

BACKGROUND

Disruption of central networks, particularly of those responsible for integrating multimodal afferents in a spatial reference frame, were proposed in the pathophysiology of lateral trunk flexion in Parkinson's disease (PD). Knowledge about the underlying neuroanatomical structures is limited.

OBJECTIVE

To investigate if decreased focal grey matter (GM) is associated with trunk flexion to the side and if the revealed GM clusters correlate with a disturbed perception of verticality in PD.

METHODS

37 PD patients with and without lateral trunk flexion were recruited. Standardized photos were taken from each patient and trunk orientation was measured by a blinded rater. Voxel-based morphometry (VBM) was used to detect associated clusters of decreased GM. The subjective visual vertical (SVV) was assessed as a marker for perception of verticality and SVV estimates were correlated with GM clusters.

RESULTS

VBM revealed clusters of decreased GM in the right posterior parietal cortex and in the right thalamus were associated with lateral trunk flexion. The SVV correlated with the extent of trunk flexion, and the side of the SVV tilt correlated with the side of trunk flexion. GM values from the thalamus correlated with the SVV estimates.

CONCLUSIONS

We report an association between neurodegenerative changes within the posterior parietal cortex and the thalamus and lateral trunk flexion in PD. These brain structures are part of a network proposed to be engaged in postural control and spatial self-perception. Disturbed perception of verticality points to a shifted egocentric spatial reference as an important pathophysiological feature.

Non-pharmacological Treatment Challenges in Early Parkinson's Disease for Axial and Cognitive Symptoms: A Mini Review

Background: Parkinson's disease (PD) is now known to be a multisystemic heterogeneous neurodegenerative disease, including a wide spectrum of both motor and non-motor symptoms. PD patients' management must encompass a multidisciplinary approach to effectively address its complex nature. There are still challenges in terms of treating axial (gait, balance, posture, speech, and swallowing) and cognitive symptoms that typically arise with disease progression becoming poorly responsive to dopaminergic or surgical treatments.

Objective: The objectives of the study are to further establish the presentation of axial and cognitive symptoms in early PD [Hoehn and Yahr (H&Y) scale ≤ 2] and to discuss the evidence for non-pharmacological approaches in early PD.

Results: Mild and subtle changes in the investigated domains can be present even in early PD. Over the last 15 years, a few randomized clinical trials have been focused on these areas. Due to the low number of studies and the heterogeneity of the results, no definitive recommendations are possible. However, positive results have been obtained, with effective treatments being high-intensity treadmill and cueing for gait disturbances, high-intensity voice treatment, video-assisted swallowing therapy for dysphagia, and warm-up exercises and Wii Fit^TM training for cognition.

Conclusions: Considering the association of motor, speech, and cognitive function, future trials should focus on multidisciplinary approaches to combined non-pharmacological management. We highlight the need for a more unified approach in managing these “orphan” symptoms, from the very beginning of the disease. The concept “the sooner the better” should be applied to multidisciplinary non-pharmacological management in PD.

Does the Degree of Trunk Bending Predict Patient Disability, Motor Impairment, Falls, and Back Pain in Parkinson's Disease?

Background: Postural abnormalities in Parkinson's disease (PD) form a spectrum of functional trunk misalignment, ranging from a "typical" parkinsonian stooped posture to progressively greater degrees of spine deviation. Objective: To analyze the association between degree of postural abnormalities and disability and to determine cut-off values of trunk bending associated with limitations in activities of daily living (ADLs), motor impairment, falls, and back pain. Methods: The study population was 283 PD patients with ≥5° of forward trunk bending (FTB), lateral trunk bending (LTB) or forward neck bending (FNB). The degrees were calculated using a wall goniometer (WG) and software-based measurements (SBM). Logistic regression models were used to identify the degree of bending associated with moderate/severe limitation in ADLs (Movement Disorders Society Unified PD Rating Scale [MDS-UPDRS] part II ≥17), moderate/severe motor impairment (MDS-UPDRS part III ≥33), history of falls (≥1), and moderate/severe back pain intensity (numeric rating scale ≥4). The optimal cut-off was identified using receiver operating characteristic (ROC) curves. Results: We found significant associations between modified Hoehn & Yahr stage, disease duration, sex, and limitation in ADLs, motor impairment, back pain intensity, and history of falls. Degree of trunk bending was associated only with motor impairment in LTB (odds ratio [OR] 1.12; 95% confidence interval [CI], 1.03-1.22). ROC curves showed that patients with LTB of 10.5° (SBM, AUC 0.626) may have moderate/severe motor impairment. Conclusions: The severity of trunk misalignment does not fully explain limitation in ADLs, motor impairment, falls, and back pain. Multiple factors possibly related to an aggressive PD phenotype may account for disability in PD patients with FTB, LTB, and FNB.

The Study of Subthalamic Deep Brain Stimulation for Parkinson Disease-Associated Camptocormia

BACKGROUND Camptocormia is an axis symptom of Parkinson disease. It remains uncertain whether treatment with medications and surgery are effective. In this study, we assessed the efficacy of subthalamic nucleus deep brain stimulation (STN DBS) in Parkinson disease-associated camptocormia and explored some of its mechanisms. MATERIAL AND METHODS Parkinson disease-associated camptocormia was diagnosed by the following procedures. All patients underwent bilateral STN DBS. The patents' camptocormia was rated by degree and MDS Unified Parkinson's Disease Rating Scale (UPDRS) item 3.13 before and after DBS surgery. Rehabilitation and psychological interventions were used after surgery, in addition to adjustments of medication and stimulus parameters. The treatment effects on camptocormia were assessed comparing medication-off (presurgery) versus stimulation-on (post-surgery). Ethical approval for this study was provided through the Center of Human Research Ethics Committee (No. 2019-35). This study trial was registered in Chinese Clinical Trial Registry (No. ChiCTR1900022655). All the participants provided written informed consent. RESULTS After DBS surgery, all of study patients' symptoms were improved, with different levels of improvement. The minimum and maximum improvement rates were 20% and 100% respectively. The score of item 3.13 of the MDS-UPDRS III and the degree of camptocormia were found to be obviously improved (P<0.05). CONCLUSIONS STN DBS can improve Parkinson disease-associated camptocormia; STN DBS assisted with rehabilitation and psychological intervention appears to be more effective.

Effects of Deep Brain Stimulation on Postural Trunk Deformities: A Systematic Review

Background

Deep brain stimulation (DBS) effects on postural deformities are still poorly explored.

Methods

Systematic review in accord with the Preferred Reporting Items for Systematic review and Meta-Analysis guidelines (PRISMA).

Results

All 38 studies that met predefined eligibility criteria had high risk of bias attributed to retrospective analysis of heterogeneous populations with variable and incompletely reported demographic and clinical characteristics, definitions, outcomes, DBS indications, targets, and settings. Five patient groups were identified in the 35 studies with individual data available: (1) parkinsonian camptocormia (n = 96): 89 patients underwent subthalamic (STN) and 7 globus pallidus pars interna (GPi) DBS. Camptocormia was the indication in 3 patients. After DBS, camptocormia improved in 57 of 96 patients (4.3-100% improvement) and remained stable or worsened in 39 of 96 patients (2-100% worsening). (2) dystonic camptocormia (n = 16): All underwent GPi-DBS. They were younger and with shorter disease duration, but longer deformity duration, compared with parkinsonian camptocormia. After GPi-DBS, camptocormia improved in all patients (50-100% improvement). (3) Parkinsonian Pisa syndrome (n = 14): 11 patients underwent STN-DBS for motor fluctuations whereas Pisa syndrome was the indication for pedunculopontine and GPi-DBS in 2 patients. After DBS, Pisa improved in 10 of 14 patients (33.3-66.7% improvement). (4) Dystonic opisthotonus: 2 young patients remarkably responded to GPi-DBS. (5) Parkinsonian anterocollis: There were variable responses in 3 patients after STN-DBS for motor fluctuations.

Conclusions

Low-quality level of evidence suggests that dystonic camptocormia and opisthotonus improve after GPi-DBS. Parkinsonian camptocormia, Pisa syndrome, and anterocollis have variable responses, and their dystonic features should be further explored.

Postural Abnormalities in Parkinson's Disease: An Epidemiological and Clinical Multicenter Study

INTRODUCTION

The overall frequency of postural abnormalities (PA) in Parkinson's disease (PD) is unknown. We evaluated the overall prevalence of PA and assessed the association with demographic and clinical variables.

METHODS

For this multicenter, cross-sectional study, consecutive PD outpatients attending 7 tertiary Italian centers were enrolled. Patients were evaluated and compared for the presence of isolated PA such as camptocormia, Pisa syndrome, and anterocollis and for combined forms (ie, camptocormia + Pisa syndrome) together with demographic and clinical variables.

RESULTS

Of the total 811 PD patients enrolled, 174 (21.5%; 95% confidence interval [CI], 18.6%-24.3%) presented PA, 144 of which had isolated PA and 30 had combined PA. The prevalence of camptocormia was 11.2% (95% CI, 9%-13.3%), Pisa syndrome 8% (95% CI, 6.2%-9.9%), and anterocollis 6.5% (95% CI, 4.9%-8.3%). Patients with PA were more often male and older with longer disease duration, more advanced disease stage, more severe PD symptoms, a bradykinetic/rigid phenotype, and poorer quality of life. They were initially treated with levodopa, and more likely to be treated with a combination of levodopa and dopamine agonist, took a higher daily levodopa equivalent daily dose, and had more comorbidities. Falls and back pain were more frequent in PD patients with PA than in those without PA. Multiple logistic regression models confirmed an association between PA and male gender, older age, Hoehn and Yahr stage, and total Unified Parkinson's Disease Rating Scale score.

CONCLUSIONS

PA are frequent and disabling complications in PD, especially in the advanced disease stages.

Pisa Syndrome in Chinese Patients With Parkinson's Disease

Objective: To investigate the prevalence and the clinical factors related to Pisa syndrome (PS) in Chinese Parkinson's disease (PD) patients.

Methods: A total of 2,167 PD patients were continuously included in this observational study. Patients with PS were identified as presented with a lateral trunk flexion of at least 10° that can be completely alleviated by passive mobilization or supine positioning. The data of the motor and non-motor symptoms including depression, anxiety and cognitive dysfunction was collected and analyzed.

Results: We found seventy-seven (3.6%) PD patients presenting with PS. The following variables including age, disease duration, levodopa equivalent daily doses (LEDD), the proportion of males, the proportion of participants using levodopa, dopaminergic agonist, amantadine and entacapone, the proportion of motor fluctuations, scores of Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), Unified PD Rating Scale (UPDRS) part III, and Hoehn and Yahr (H&Y) stage were significantly higher in patients with PS compared with patients without PS (P < 0.05). Scores of the Frontal Assessment Battery (FAB) and the Montreal Cognitive Assessment (MoCA) were not different between the two groups. The binary logistic regression model indicated that the presence of PS was associated with older age (OR = 1.027, P = 0.030), higher LEDD (OR = 1.002, P < 0.001) and a higher UPDRS III score (OR = 1.060, P < 0.001), but had no relationship with HAMD and HAMA scores.

Conclusion: PS is relatively rare (3.6%) in Chinese PD patients. It is likely associated with older age, higher LEDD and more severe motor disabilities. However, non-motor symptoms such as depression, anxiety, and cognitive dysfunction have no association with PS in PD. These findings provided important complementary information for identifying the underlying mechanisms of PS.

Pisa syndrome in Idiopathic Normal Pressure Hydrocephalus

INTRODUCTION

Idiopathic Normal Pressure Hydrocephalus (iNPH) is a complex syndrome of ventriculomegaly that can include parkinsonian-like features besides the classical triad of cognitive decline, urinary incontinence, and gait/balance disturbances. Pisa syndrome (PS) is a postural abnormality often associated with parkinsonism and defined as lateral trunk flexion greater than 10° while standing that resolves in the supine position. We reported a case series of classical "fixed" PS and one case of "Metronome" recurrent side-alternating PS in iNPH, displaying opposite electromyographic patterns of paraspinal muscles.

METHODS

Eighty-five iNPH patients were followed longitudinally for at least one year through scheduled clinical and neuropsychological visits.

RESULTS

Five (5.9%) subjects revealed PS. None of them had nigrostriatal dopaminergic involvement detected by [123I]FP-CIT SPECT. Among these patients, four had "fixed" PS, whereas one showed a recurrent side-alternating PS which repeatedly improved after ventriculo-peritoneal shunt and following adjustments of the valve-opening pressure of the shunt system.

DISCUSSION

This is the first case series of PS in iNPH and the first report of "Metronome" PS in iNPH. The prompt response of the abnormal trunk postures through cerebrospinal fluid (CSF) shunt surgery suggests a causative role of an altered CSF dynamics. PS and gait disorders in iNPH could be explained by a direct involvement of cortico-subcortical pathways and subsequent secondary brainstem involvement, with also a possible direct functional damage of the basal ganglia at the postsynaptic level, due to enlargement of the ventricular system and impaired CSF dynamics. The early detection of these cases supports a proper surgical management.

Pisa Syndrome in Parkinson's Disease Is Associated With Specific Cognitive Alterations

Background: Pisa syndrome (PS) is a lateral flexion of the trunk frequently associated with Parkinson's disease (PD). The pathophysiology of PS remains unclear, but the role of cognitive deficits has been postulated. Methods: We included 12 consecutive PD patients with PS (PS+) and 12 PD patients without PS (PS-) matched for gender, age, level of education, PD duration, and PD stage. As primary aim, we compared the neuropsychological scores of 16 tests evaluating 6 cognitive domains between PS+ and PS-. Additionally, we evaluated the presence of misperception of the trunk position in PS+, defined as a mismatch between the objective vs. subjective evaluation of the trunk bending angle >5°, and analyzed whether a correlation exists between the misperception of the trunk position and alterations in the visual-spatial abilities. Results: PS+ group showed significantly worse performances in the visual-spatial abilities (p: 0.008), attentional domain (p: 0.001), and language domain (p: 0.023). No differences were found in the other cognitive domains nor in the general cognitive assessment. All PS+ patients showed a misperception of the trunk position, with an average underestimation of the trunk bending angle of 11.7° ± 4.3. The degree of misperception of the trunk position showed a trend toward a correlation with the visual-spatial scores (p: 0.089). Conclusions: The study reveals an association between PS and specific cognitive alterations, suggesting a possible link between the abnormal posture of PD patients with PS and their cognitive functions.

Recent advancements in lateral trunk flexion in Parkinson disease

Purpose of review

Understanding the pathophysiologic underpinnings of lateral trunk flexion (LTF) in Parkinson disease (PD) has been growing. Adjusting antiparkinsonian medications, botulinum toxin, or surgical intervention has been found efficacious in some patients. Nevertheless, these treatments remain limited, often resulting in inadequate outcomes. We review patients with LTF with PD, including recent advancements in treatment and neuroimaging examination.

Recent findings

The basal ganglia system is a major contributing factor to LTF, and the therapeutic intervention also targets the basal ganglia system, including dystonic contraction. The perceptions of the postural verticality or spatial cognition of the correct body orientation promote the severity of LTF or result in a chronic condition with irreversible structural deformities.

Conclusion

The combination of pharmacologic interventions with nonpharmacologic interventions, such as rehabilitation, might be needed to manage LTF, and the initiation of these treatments should be started as early as possible.

Hand, foot, and spine deformities in parkinsonian disorders

Hand and foot deformities, known as "striatal deformities", and other musculoskeletal abnormalities such as dropped head, bent spine, camptocormia, scoliosis and Pisa syndrome, are poorly understood and often misdiagnosed features of Parkinson's disease and other parkinsonian syndromes. These deformities share some similarities with known rheumatologic conditions and can be wrongly diagnosed as rheumatoid arthritis, osteoarthritis, psoriatic arthritis, Dupuytren's contracture, trigger finger, or other rheumatologic or orthopedic conditions. Neurologists, rheumatologists, and other physicians must be familiar with these deformities to prevent misdiagnosis and unnecessary diagnostic tests, and to recommend appropriate treatment options.

Effect of subthalamic deep brain stimulation on posture in Parkinson's disease: A blind computerized analysis

INTRODUCTION

We sought to assess the effect of subthalamic deep brain stimulation (STN DBS) on Parkinson's disease (PD)-associated postural abnormalities.

METHODS

A computerized analysis of posture was used to quantify the thoracolumbar, thoracic, and cervical-occipital ventral angles, as well as the thoracolumbar and cervical-occipital lateral angles from the video-repository of three specialized movement disorder centers (n = 158 patients). Data was extracted from frames from video-recordings in the pre-surgical medication-ON (dopaminergic therapy) and post-surgical stimulation-ON/medication-ON states (STN DBS plus dopaminergic therapy). The sum of the five postural angles (global postural angle) was used to compare pre-vs. post-surgical trunk posture alterations. A multivariate analysis was used to examine the association between changes in the postural angles and demographic or clinical variables.

RESULTS

There was a 6.7% amelioration in the global postural angle between the pre- and post-surgical assessments (p = 0.031). Motor response to and pre-surgical dosage of levodopa, male gender, and shorter PD duration were identified as predictors for posture improvement after STN DBS. Cases meeting criteria for lower (n = 2) or upper (n = 1) camptocormia respectively improved by 48.1% in the ventral thoracolumbar angle (from 36.4 ± 0.0° to 18.9 ± 4.2°) and 13.8% in the ventral thoracic angle (from 49.1° to 42.3°). Cases meeting criteria for Pisa syndrome (n = 2) improved by 67.5% in the lateral thoracolumbar angle (from 16.9 ± 2.0° to 5.5 ± 4.7°).

CONCLUSIONS

STN DBS has a relatively small but significant effect on PD-associated postural abnormalities, potentially enhancing the effect of dopaminergic medications alone.

Long-term Outcome of Globus Pallidus Internus Stimulation for Pisa Syndrome

Pisa syndrome, defined as dystonia leading to lateral flexion of the spine, is an increasingly recognized complicating factor in the treatment of Parkinson’s disease (PD). Symptoms may persist despite medical therapy, or medical therapy may not be tolerated due to adverse effects. Here, we demonstrate the long-term efficacy of deep brain stimulation (DBS) at the globus pallidus internus (GPi) for the treatment of Pisa syndrome. One patient with Pisa syndrome and Parkinson disease underwent bilateral GPi DBS with computed tomography (CT)-and microelectrode-based guidance. Follow-up with neurosurgery and neurology was done over a four-year period. The patient’s axial deformity decreased from approximately 45 to 25 degrees, and he reported significant relief from back pain. Bilateral GPi DBS is a safe and effective option for Pisa syndrome in patients with PD.

Pisa Syndrome in Parkinson's Disease: Evidence for Bilateral Vestibulospinal Dysfunction

Introduction

Pisa syndrome (PS) is a postural complication of Parkinson's disease (PD). Yet, its pathophysiology remains unclear, although a multifactorial component is probable. Cervical vestibular evoked myogenic potentials (cVEMPs) explore vestibulospinal pathway, but they have not been measured yet in PD patients with PS (PDPS) to assess a potential vestibular impairment.

Materials and Methods

We enrolled 15 PD patients, 15 PDPS patients, and 30 healthy controls (HCs). They underwent neurological examination and were examined with Unified Parkinson's Disease Rating Scale II-III (UPDRSII-III), audiovestibular workup, and cVEMP recordings. Data were analysed with Chi-square, one-way ANOVA, multinomial regression, nonparametric, and Spearman's tests.

Results

cVEMPs were significantly impaired in both PD and PDPS compared with HCs. PDPS exhibited more severe cVEMP abnormalities with prevalent bilateral loss of potentials, compared with the PD group, in which a prevalent unilateral loss was instead observed. No clinical-neurophysiological correlations emerged.

Conclusions

Differently from HC, cVEMPs are altered in PD. Severity of cVEMPs alterations increases from PD without PS to PDPS, suggesting an involvement of vestibulospinal pathway in the pathophysiology of PS. Our results provide evidence for a significant impairment of cVEMPs in PDPS patients and encourage further studies to test validity of cVEMPs as diagnostic and prognostic biomarkers of PD progression.

Parkinson's disease: symptoms, treatment options and nursing care

Idiopathic Parkinson's disease (IPD) is a progressive neurodegenerative condition that causes various motor and non-motor symptoms and will often have life-changing effects for those with the condition, as well as for their family and carers. Nurses can make a significant difference to the lives of those affected by Parkinson's disease, whether in the acute setting, community setting or in care homes. This article explores the causes and progressive clinical pathway of IPD using an evidence-based approach. It emphasises the valuable role of the multidisciplinary team and of the nurse, in particular, in monitoring and improving the quality of life of those with the condition and their family and carers.

Pisa syndrome in Parkinson's disease: electromyographic quantification of paraspinal and non-paraspinal muscle activity

Patients with Parkinson's disease (PD) and Pisa syndrome (PS) may present tonic dystonic or compensatory (i.e. acting against gravity) hyperactivity in the paraspinal and non-paraspinal muscles. Electromyographic (EMG) activity was measured in nine patients with PD and PS, three with PD without PS, and five healthy controls. Fine-wire intramuscular electrodes were inserted bilaterally into the iliocostalis lumborum (ICL), iliocostalis thoracis (ICT), gluteus medius (GM), and external oblique (EO) muscles. The root mean square (RMS) of the EMG signal was calculated and normalized for each muscle. In stance condition, side-to-side muscle activity comparisons showed a higher RMS only for the contralateral ICL in PD patients with PS (p=0.028). Moreover, with increasing degrees of lateral flexion, the activity of the EO and the ICL muscles progressively increased and decreased, respectively. The present data suggest that contralateral paraspinal muscle activity plays a crucial compensatory role and can be dysfunctional in PD patients with PS.

Subthalamic deep brain stimulation and trunk posture in Parkinson's disease

OBJECTIVES

We sought to assess the efficacy of subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson's disease (PD)-associated trunk posture abnormalities retrospectively analyzing data from 101 patients reporting mild-to-severe trunk posture abnormalities of a cohort of 216 PD patients treated with STN-DBS at our center.

METHODS

Abnormal trunk posture was rated on a scale of 0 (normal) to 4 (marked flexion with an extreme abnormality of posture) as per the grading score reported in the Unified Parkinson's Disease Rating Scale. The independent effect of STN-DBS on trunk posture was assessed comparing Medication-Off (presurgery) vs Stimulation-On/Medication-Off (post-surgery). The combined effect of STN-DBS plus levodopa was evaluated comparing Medication-On (presurgery) vs Stimulation-On/Medication-On (post-surgery). Analyses were conducted considering both the entire cohort of patients and the subgroup with camptocormia (CMC) and Pisa syndrome (PS).

RESULTS

The independent effect of STN-DBS resulted in a 41.4% improvement in abnormal trunk posture severity (P < .001), with 78.2% of patients (n = 79) reporting an improvement of at least 1 point. The combined effect of STN-DBS and levodopa resulted in a 30.9% improvement (P = .061), with 54.5% of patients (n = 55) reporting an improvement of at least 1 point. The subanalysis of patients with CMC (n = 23) and PS (n = 5) showed a 42.7% improvement in abnormal posture severity when considering the independent effect of STN-DBS (P < .001) and 30.5% when considering the combined effect of STN-DBS and levodopa (P < .001).

CONCLUSIONS

STN-DBS may have the potential for improving posture in patients with advanced PD.

Managing Gait, Balance, and Posture in Parkinson's Disease

PURPOSE OF REVIEW

Postural instability and gait difficulties inexorably worsen with Parkinson's disease (PD) progression and become treatment resistant, with a severe impact on autonomy and quality of life. We review the main characteristics of balance instability, gait disabilities, and static postural alterations in advanced PD, and the available treatment strategies.

RECENT FINDINGS

It remains very difficult to satisfactorily alleviate gait and postural disturbances in advanced PD. Medical and surgical interventions often fail to provide satisfactory or durable alleviation of these axial symptoms, that may actually call for differential treatments. Exercise and adapted physical activity programs can contribute to improving the patients' condition. Gait, balance, and postural disabilities are often lumped together under the Postural Instability and Gait Difficulties umbrella term. This may lead to sub-optimal patients' management as data suggest that postural, balance, and gait problems might depend on distinct underlying mechanisms. We advocate for a multidisciplinary approach from the day of diagnosis.

Antipsychotic-Induced Pisa Syndrome: A 2-Year Follow-up Study

OBJECTIVES

Pisa syndrome is characterized by lateral trunk flexion. It is an uncommon adverse drug reaction in patients on antipsychotic medication. Although Pisa syndrome has been reported in patients on antipsychotic treatment, previous studies have not discussed the prognosis of patients with Pisa syndrome. We studied psychiatric patients with Pisa syndrome following antipsychotic treatment for a 2-year period.

METHODS

From January 2012 to December 2014, 13 inpatients with Pisa syndrome following antipsychotic treatment were identified at our institution, from a prospectively collected database. These patients were studied for a 2-year period.

RESULTS

The prevalence rate of Pisa syndrome during neuroleptic treatment was 0.45% in men and 0.37% in women, with a collective prevalence rate of 0.42%. The mean age of patients with Pisa syndrome was 47 years. Eight (61.5%) of the cases had a position with a tilt toward the right side. In 5 (38.5%) of the cases, a tilt toward the left side was observed. The average Cobb angle of the trunk was 17.3 (SD, 4.0) degrees. On presentation with Pisa syndrome within 3 months of medication modification, the pattern of trunk dystonia had a significantly shorter duration (P = .024) compared with that seen in the tardive-onset group.

CONCLUSIONS

Pisa syndrome is an uncommon adverse event that can also be chronic or recurrent, especially in those with tardive onset. We should be aware of the risks in patients with the following predisposing factors: old age, chronic psychosis, long-term antipsychotic use, advanced drug-induced parkinsonism, and combined pharmacologic treatment.

Pisa Syndrome in Parkinson's Disease: Pathogenic Roles of Verticality Perception Deficits

We elucidated whether verticality misperception is associated with the generation of Pisa syndrome (PS) in patients with Parkinson's disease (PD). To examine the heterogenous influence of verticality perception, we also identified the characteristics distinguishing between PD patients with PS who tilted toward the deviation of perceived verticality and those who did not. Subjective visual vertical (SVV) testing was performed in 54 PD patients with PS and 36 without PS to measure verticality perception. Other potential risk factors for PS were evaluated by assessing the asymmetry of motor symptoms, EMG activities of paraspinal muscles, bithermal caloric tests, back pain history, and Berg Balance Scale. Abnormal SVV (odds ratio (OR) 18.40, p = 0.006), postural imbalance (OR 0.71, p = 0.046), and unilateral EMG hyperactivity of paraspinal muscles (OR 39.62, p = 0.027) were independent contributors to PS. In subgroup analysis, EMG hyperactivity of paraspinal muscles contralateral to the leaning side and postural imbalance were associated with PD patients with PS who tilted toward the SVV deviation, whereas back pain was more frequent in those who did not. Verticality misperception is a potent risk factor for PS in PD and contributes differentially to PS depending on the congruence between its direction and PS direction, indicating distinct pathogenic roles.