Mechanism of camptocormia in Parkinson's disease analyzed by tilt table-EMG recording

Botulinum Toxin for Axial Postural Abnormalities in Parkinson's Disease: A Systematic Review

Axial postural abnormalities (APAs), characterized by their frequency, disabling nature, and resistance to pharmacological treatments, significantly impact Parkinson's disease and atypical Parkinsonism patients. Despite advancements in diagnosing, assessing, and understanding their pathophysiology, managing these complications remains a significant challenge. Often underestimated by healthcare professionals, these disturbances can exacerbate disability. This systematic review assesses botulinum toxin treatments' effectiveness, alone and with rehabilitation, in addressing APAs in Parkinson's disease, utilizing MEDLINE (PubMed), Web of Science, and SCOPUS databases for source material. Of the 1087 records retrieved, 16 met the selection criteria. Most research has focused on botulinum toxin (BoNT) as the primary treatment for camptocormia and Pisa syndrome, utilizing mostly observational methods. Despite dose and injection site variations, a common strategy was using electromyography-guided injections, occasionally enhanced with ultrasound. Patients with Pisa syndrome notably saw consistent improvements in APAs and pain. However, studies on the combined effects of botulinum toxin and rehabilitation are limited, and antecollis is significantly under-researched. These findings recommend precise BoNT injections into hyperactive muscles in well-selected patients by skilled clinicians, avoiding compensatory muscles, and underscore the necessity of early rehabilitation. Rehabilitation is crucial in a multidisciplinary approach to managing APAs, highlighting the importance of a multidisciplinary team of experts.

Predictors and Pathophysiology of Axial Postural Abnormalities in Parkinsonism: A Scoping Review

Background

Postural abnormalities involving the trunk are referred to as axial postural abnormalities and can be observed in over 20% of patients with Parkinson's disease (PD) and in atypical parkinsonism. These symptoms are highly disabling and frequently associated with back pain and a worse quality of life in PD. Despite their frequency, little is known about the pathophysiology of these symptoms and scant data are reported about their clinical predictors, making it difficult to prompt prevention strategies.

Objectives

We conducted a scoping literature review of clinical predictors and pathophysiology of axial postural abnormalities in patients with parkinsonism to identify key concepts, theories and evidence on this topic.

Methods

We applied a systematic approach to identify studies, appraise quality of evidence, summarize main findings, and highlight knowledge gaps.

Results

Ninety-two articles were reviewed: 25% reported on clinical predictors and 75% on pathophysiology. Most studies identified advanced disease stage and greater motor symptoms severity as independent clinical predictors in both PD and multiple system atrophy. Discrepant pathophysiology data suggested different potential central and peripheral pathogenic mechanisms.

Conclusions

The recognition of clinical predictors and pathophysiology of axial postural abnormalities in parkinsonism is far from being elucidated due to literature bias, encompassing different inclusion criteria and measurement tools and heterogeneity of patient samples. Most studies identified advanced disease stage and higher burden of motor symptoms as possible clinical predictors. Pathophysiology data point toward many different (possibly non-mutually exclusive) mechanisms, including dystonia, rigidity, proprioceptive and vestibular impairment, and higher cognitive deficits.

Analysis of abnormal posture in patients with Parkinson's disease using a computational model considering muscle tones

Patients with Parkinson's disease (PD) exhibit distinct abnormal postures, including neck-down, stooped postures, and Pisa syndrome, collectively termed "abnormal posture" henceforth. In the previous study, when assuming an upright stance, patients with PD exhibit heightened instability in contrast to healthy individuals with disturbance, implying that abnormal postures serve as compensatory mechanisms to mitigate sway during static standing. However, limited studies have explored the relationship between abnormal posture and sway in the context of static standing. Increased muscle tone (i.e., constant muscle activity against the gravity) has been proposed as an underlying reason for abnormal postures. Therefore, this study aimed to investigate the following hypothesis: abnormal posture with increased muscle tone leads to a smaller sway compared with that in other postures, including normal upright standing, under the sway minimization criterion. To investigate the hypothesis, we assessed the sway in multiple postures, which is determined by joint angles, including cases with bended hip joints. Our approach involved conducting forward dynamics simulations using a computational model comprising a musculoskeletal model and a neural controller model. The neural controller model proposed integrates two types of control mechanisms: feedforward control (representing muscle tone as a vector) and feedback control using proprioceptive and vestibular sensory information. An optimization was performed to determine the posture of the musculoskeletal model and the accompanied parameters of the neural controller model for each of the given muscle tone vector to minimize sway. The optimized postures to minimize sway for the optimal muscle tone vector of patients with PD were compared to the actual postures observed in these patients. The results revealed that on average, the joint-angle differences between these postures was <4°, which was less than one-tenth of the typical joint range of motion. These results suggest that patients with PD exhibit less sway in the abnormal posture than in other postures. Thus, adopting an abnormal posture with increased muscle tone can potentially serve as a valid strategy for minimizing sway in patients with PD.

Analysis of the Relationship Between Muscle Tones and Abnormal Postures in a Computational Model

Patients with Parkinson's disease (PD), a neurodegenerative disorder, exhibit a characteristic posture known as a forward flexed posture. Increased muscle tone is suggested as a possible cause of this abnormal posture. For further analysis, it is necessary to measure muscle tone, but the experimental measurement of muscle tone during standing is challenging. The aim of this study was to examine the hypothesis that "In patients with PD, abnormal postures are those with a small sway at increased muscle tones" using a computational model. The muscle tones of various magnitudes were estimated using the computational model and standing data of patients with PD. The postures with small sway at the estimated muscle tones were then calculated through an optimization method. The postures and sway calculated using the computational model were compared to those of patients with PD. The results showed that the differences in posture and sway between the simulation and experimental results were small at higher muscle tones compared to those considered plausible in healthy subjects by the simulations. This simulation result indicates that the reproduced sway at high muscle tones is similar to that of actual patients with PD and that the reproduced postures with small sway locally at high muscle tones in the simulations are similar to those of patients with PD. The result is consistent with the hypothesis, reinforcing the hypothesis.Clinical relevance- This study implies that improving the increased muscle tone in patients with PD may lead to an improved abnormal posture.

Axial postural abnormalities and pain in Parkinson's disease

Axial postural abnormalities and pain are two main determinants of poor quality of life in patients with Parkinson's disease (PD). Indeed, a detailed characterization of pain and other non-motor symptoms in patients with PAs has not been provided yet. The aim of this study is to assess the phenomenology of pain and other non-motor symptoms in PD patients with Pisa syndrome and camptocormia compared to PD patients without axial postural abnormality. Forty-five PD participants were equally distributed in three groups: patients with Pisa syndrome (PS), patients with Camptocormia (CC), and patients without postural abnormalities (PD). Pain characteristics were assessed by Kings Parkinson's Pain Scale (KPPS), brief pain inventory (BPI), and numeric pain rating scale (NRS). All participants completed clinical assessments by non-motor symptom scale (NMSS), and movement disorder society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) parts II-III. Patients with and without axial postural abnormalities showed one or more types of pain, being fluctuation, nocturnal, chronic, and musculoskeletal the most frequently reported in Pisa Syndrome and camptocormia. PD group compared with PS and CC groups showed differences in the KPPS, NMSS, BPI pain severity and interference, and NRS total scores. No significant differences were found between PS group compared with CC group with exception of the NMSS total scores. PD patients with Pisa syndrome or camptocormia have a higher burden of musculoskeletal, chronic and fluctuation pain than PD patients without axial postural abnormalities, suggesting different etiologies of pain and possible different treatments.

Effect of intramuscular lidocaine injection with physical therapy on camptocormia in patients with Parkinson's disease who had previously had deep brain stimulation

[Purpose] We aimed to evaluate the effects of an intervention consisting of intramuscular lidocaine injection in combination with physical therapy on the standing posture, balance ability, and walking ability in patients with Parkinson's disease who had camptocormia after deep brain stimulation. [Participants and Methods] The participants were nine patients with Parkinson's disease who had previously undergone deep brain stimulation. The intervention comprised a lidocaine injection into the abdominal external oblique muscles for five days in combination with physical therapy, including body weight-supported treadmill training for two weeks. Before and after the intervention, the total and upper camptocormia angles were used to assess the standing posture; the Berg balance scale was used to assess the balancing ability; and maximum walking speed and stride length were used to assess the walking ability. [Results] The total and upper camptocormia angles, and Berg balance scale improved significantly more after the intervention than before. Before and after the intervention, there was no significant difference in maximum walking speed, but the stride length was significantly greater after the intervention than before. [Conclusion] The intervention was effective in alleviating camptocormia and improving the balance and walking abilities of patients with Parkinson's disease with camptocormia after deep brain stimulation.

Insufficiency of trunk extension and impaired control of muscle force in Parkinson's disease with camptocormia

OBJECTIVE

To examine the aetiology of parkinsonian camptocormia, a non-fixed pathological forward bending of the trunk, by measuring trunk muscle activation and force regulation in Parkinson patients with (PD + CC) and without (PD) camptocormia matched for disease severity, and in age- and sex-matched healthy controls (HC).

METHODS

The isometric forces of trunk extension and flexion were measured in PD + CC, PD and HC. Neuromuscular efficiency (increase of extension force per increase of paravertebral muscle surface electromyography signal) and the ability to maintain a constant submaximal trunk extension force were examined.

RESULTS

Peak trunk extension force was significantly lower in PD + CC and PD than in HC, with PD + CC non-significantly weaker than PD. Compared with HC and with PD, the neuromuscular efficiency of trunk extension was significantly reduced in PD + CC. The variability of the force output (coefficient of variation) was significantly larger for PD + CC than for HC or PD.

CONCLUSION

The reduced neuromuscular efficiency of trunk extension separates PD + CC from PD. Moreover, control of the trunk extensor force is impaired in PD + CC.

SIGNIFICANCE

There is weakness and a force control deficit in parkinsonian camptocormia suggesting a disturbed sensory-motor integration, which may contribute to myopathic changes in the trunk extensor muscles.

Upper camptocormia in Parkinson's disease: Neurophysiological and imaging findings of both central and peripheral pathophysiological mechanisms

BACKGROUND

Camptocormia is a disabling complication of Parkinson's disease (PD), but its pathophysiology is poorly elucidated. Depending on the fulcrum of forward trunk flexion, two subtypes have been defined, upper (UCC) and lower camptocormia, the former being much more frequent. The aim of the study was to explore possible pathophysiological mechanisms of PD-related UCC.

METHODS

Ten PD patients with UCC (UCC-PD) and ten PD patients without camptocormia (NoUCC-PD) underwent simultaneous electromyography (EMG) of thoracic paraspinal (TPS), obliquus externus abdominis (OEA), rectus abdominis (RA), and iliopsoas (IP) muscles during relaxed standing (both groups) and trunk realignment (UCC-PD group). Quantitative EMG and magnetic resonance imaging (MRI) of TPS muscles were also performed.

RESULTS

UCC-PD patients showed hyperactivity of TPS and OEA muscles in quiet stance. During voluntary trunk extension, hyperactivity of OEA muscles persisted, thus revealing a co-contraction of flexor and extensor trunk muscles. Motor unit potentials (MUP) of TPS muscles showed shorter duration (p = 0.005) and lower amplitude (p = 0.004) in UCC-PD than in NoUCC-PD patients. MRI did not detect significant between-group differences in the cross-sectional area and fat fraction of TPS muscles, although the latter was higher in the UCC-PD than in the NoUCC-PD group at all thoracic levels.

CONCLUSION

Our findings suggest that hyperactivity of OEA might sustain UCC in PD. Concurrent mild myopathic changes in TPS muscles in PD with UCC may be secondary to muscle disuse but nevertheless may contribute to abnormal trunk posture.

Do Upper and Lower Camptocormias Affect Gait and Postural Control in Patients with Parkinson's Disease? An Observational Cross-Sectional Study

Gait impairments and camptocormia (CC) are common and debilitating in patients with Parkinson's disease (PD). Two types of CC affect patients with PD, but no studies investigated their relative contribution in worsening gait and postural control. Therefore, we investigated spatiotemporal gait parameters, gait variability, and asymmetry and postural control in PD patients (Hoehn & Yahr ≤4) with upper CC and lower CC and patients without CC. This observational cross-sectional study involving patients with PD and upper CC (n=16) and lower CC (n=14) and without CC (n=16). The primary outcome measure was gait speed assessed by the GAITRite System. The secondary outcome measures were other spatiotemporal parameters, gait variability, and asymmetry. Postural control and balance were assessed with posturography and the Mini-BESTest. Patients with lower CC showed a higher H&Y stage (p=0.003), a worse PDQ8 (p=0.042), and a lower Mini-BESTest score (p=0.006) than patients with PD without CC. Patients with lower CC showed a reduced gait speed (p=0.012), stride length, and velocity than patients with PD without CC. Upper CC patients showed a higher stride length than lower CC ones (p=0.007). In the eyes open and closed condition, patients with lower CC showed a higher (worse) velocity of CoP displacement in mediolateral direction and length of CoP than patients with PD without CC. No significant between-group differences were measured in gait variability and asymmetry. In conclusion, lower CC was associated with more severe gait and postural control impairment than patients with upper CC and without CC. Categorizing CC based on the bending fulcrum is compulsory to identify patients with the worst performance and to implement specific rehabilitation programs.

Injection of Onabotulinum Toxin A into the Bilateral External Oblique Muscle Attenuated Camptocormia: A Prospective Open-Label Study in Six Patients with Parkinson's Disease

INTRODUCTION

Camptocormia (severe bending of the spine) is a debilitating complication of Parkinson's disease (PD) without established treatment. Botulinum toxin (BT) may be beneficial, but data is scarce regarding the efficacy of administration of BT into the bilateral external oblique (EO) muscle for treatment of camptocormia in PD.

METHODS

Six patients with PD and camptocormia, with flexion of the thoracic spine, were enrolled in the study. BT (75 or 90 units, onabotulinum toxin A) were injected into each EO bilaterally under sonographic guidance. Camptocormia angle (CA) was defined as the angle between the acromion-greater trochanter line and a vertical line. CA and disabling symptoms were evaluated during the treatment course.

RESULTS

Two weeks after the injection of BT, the mean CA showed significant attenuation [median (interquartile range); 38° (23.5°) vs. 18° (21°), p = 0.028]. Subjective relief was present in cases 1-3 and 6, and absent in cases 4 and 5. Cases 1-3 received repeated injections to maintain the amelioration; in cases 1 and 2, this was for 1 year or longer, while falls of case 3 limited the amelioration.

CONCLUSION

Botulinum therapy into bilateral EO attenuated the angle of thoracic-level camptocormia in six patients with PD over the observation period of 2 weeks. The reproducibility of the results, long-term efficacy, and subjective relief of symptoms require further examination.

Diagnostic criteria for camptocormia in Parkinson's disease: A consensus-based proposal

INTRODUCTION

Camptocormia is defined as an involuntary, marked flexion of the thoracolumbar spine appearing during standing or walking and resolving in the supine position or when leaning against a wall. However, there is no established agreement on the minimum degree of forward flexion needed to diagnose camptocormia. Likewise, the current definition does not categorize camptocormia on the basis of the bending fulcrum.

METHODS

We performed a survey among movement disorders experts to identify camptocormia using images of patients with variable degrees and types of forward trunk flexion by fulcrum (upper and lower fulcra). We tested the subsequently generated diagnostic criteria in a sample of 131 consecutive patients referred for evaluation of postural abnormalities.

RESULTS

Experts reached full consensus on lower camptocormia (L1-Sacrum, hip flexion) with a bending angle ≥30° and upper camptocormia (C7 to T12-L1) with a bending angle ≥45°. This definition detected camptocormia in 9/131 consecutive PD patients (2 upper/7 lower) but excluded camptocormia in 71 patients considered to have camptocormia by the referring neurologist.

CONCLUSIONS

Camptocormia can be defined as "an involuntary flexion of the spine appearing during standing or walking and resolving in the supine position of at least 30° at the lumbar fulcrum (L1-Sacrum, hip flexion, i.e. lower camptocormia) and/or at least 45° at the thoracic fulcrum (C7 to T12-L1, i.e. upper camptocormia)". Strict criteria for camptocormia are met by 7% of patients with abnormal posture. The ascertainment of upper and lower camptocormia subtypes could improve the validity of epidemiological studies and assist future therapeutic trials.

Pathophysiological Concepts and Treatment of Camptocormia

Camptocormia is a disabling pathological, non-fixed, forward bending of the trunk. The clinical definition using only the bending angle is insufficient; it should include the subjectively perceived inability to stand upright, occurrence of back pain, typical individual complaints, and need for walking aids and compensatory signs (e.g. back-swept wing sign). Due to the heterogeneous etiologies of camptocormia a broad diagnostic approach is necessary. Camptocormia is most frequently encountered in movement disorders (PD and dystonia) and muscles diseases (myositis and myopathy, mainly facio-scapulo-humeral muscular dystrophy (FSHD)). The main diagnostic aim is to discover the etiology by looking for signs of the underlying disease in the neurological examination, EMG, muscle MRI and possibly biopsy. PD and probably myositic camptocormia can be divided into an acute and a chronic stage according to the duration of camptocormia and the findings in the short time inversion recovery (STIR) and T1 sequences of paravertebral muscle MRI. There is no established treatment of camptocormia resulting from any etiology. Case series suggest that deep brain stimulation (DBS) of the subthalamic nucleus (STN-DBS) is effective in the acute but not the chronic stage of PD camptocormia. In chronic stages with degenerated muscles, treatment options are limited to orthoses, walking aids, physiotherapy and pain therapy. In acute myositic camptocormia an escalation strategy with different immunosuppressive drugs is recommended. In dystonic camptocormia, as in dystonia in general, case reports have shown botulinum toxin and DBS of the globus pallidus internus (GPi-DBS) to be effective. Camptocormia in connection with primary myopathies should be treated according to the underlying illness.