Use of Botulinum Neurotoxin in Parkinson's Disease: A Critical Appraisal

Research Progress of Camptocormia in Parkinson Disease

Camptocormia, also known as bent spine syndrome, primarily affects individuals with Parkinson disease (PD). This review provides an overview of camptocormia in PD, covering its definition, epidemiology, causes, diagnosis, and treatment. In the epidemiology section, we delve into its prevalence, gender disparities, and ongoing genetic research. Regarding diagnosis and assessment, we discuss evolving diagnostic criteria and measurement techniques, as well as new diagnostic tools. For management and treatment, a wide array of options is available, from conservative methods such as physical therapy and botulinum toxin injections to surgical interventions such as spinal orthopedic surgery and deep brain stimulation. We stress the significance of personalized care and multidisciplinary collaboration. This comprehensive review aims to provide clinicians, researchers, and healthcare professionals with a comprehensive understanding of camptocormia in PD, highlighting its clinical features, diagnostic strategies, management approaches, and future perspectives.

The effectiveness and safety of botulinum toxin injections for managing motor disorders of patients with Parkinson's disease: A meta-analysis of randomized controlled trials

This study aimed to assess the effectiveness and safety of botulinum toxin (BTX) injections for managing motor disorders in patients with Parkinson's disease (PD). An electronic search was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data from available randomized controlled trials (RCTs) assessing BTX injections for motor disorders in PD patients were extracted for meta-analysis. Ultimately, 215 patients from eight RCTs were enrolled. Pooled analyses indicated that BTX was more effective than placebo in improving tremor (standardized mean difference [SMD] = 0.96, 95% CI [0.34, 1.58], p < 0.01), whereas no notable differences were observed between BTX and placebo regarding freezing of gait (SMD = 0.66, 95% CI [-0.26, 1.58], p = 0.162), United Parkinson's Disease Rate Scale (UPDRS) III score (SMD = -0.20, 95% CI [-1.17, 0.76], p = 0.68) and clinical global impression (CGI) score (SMD = 0.84, 95% CI [-0.74, 2.42], p = 0.298). Adverse events related to BTX injections were comparable to placebo (OR = 1.74, 95% CI [0.59, 5.14], p = 0.32). The current evidence suggests that BTX is effective and safe in treating PD tremor but fails to provide therapeutic benefits for freezing of gait and motor functional scores in PD patients. Furthermore, the limited number of included studies and heterogeneity in BTX intervention protocols suggest more research is needed, with additional standardized RCTs, to better understand and optimize BTX injections for motor disorders in PD.

Botulinum toxin therapy in Parkinson disease-related lower limb dystonia. An 8 year retrospective review

Background

Lower extremity dystonia (LED) is a frequent complication of Parkinson disease (PD). Treatment with botulinum neurotoxinA (BoNTA) over 8 years was retrospectively reviewed.Cases14 patients with LED received an average of 3.86 injections (1-8). Mean interval was 40 weeks (median of 25). Average dose was 182 units. Injections were well-tolerated. Using a 6 point scale, there was an average of 3.37 point improvement in disability after each session, with average duration of 28.56 weeks (median 11 weeks). After mean follow-up of 101 weeks, disabling dystonia was not present in 11 of 14 patients.

Conclusions

Botulinum toxin is safe and effective in PD related LED. Good response to the first two injection sessions was significantly associated with greater likelihood of long-term response. Assertive BoNTA dosing may lead to sustained remission of symptoms. As natural history of LED in PD has not been reported, prospective placebo-controlled studies are needed.

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.

Use of botulinum toxin in the management of dystonia in Parkinson's disease

Botulinum toxin is one of the most potent neurotoxins, but when injected into an overactive muscle, it can transiently alleviate an involuntary movement, such as dystonia. The primary aim of this article is to provide a comprehensive review of the various forms of dystonia observed in patients with Parkinson's disease who can benefit from a therapeutic trial of botulinum toxin. Although most of these indications are not supported by randomized controlled clinical trials and, therefore, not approved by the Food and Drug Administration, there are many open-label trials supporting a large body of empirical experience testifying to the benefits of botulinum toxin treatment in these conditions.

Hypertonia of the Big Toe Revealing Parkinson's Disease: A Case Report

Despite being less commonly discussed than other motor symptoms such as tremors and bradykinesia, hypertonia of the hallux holds diagnostic and prognostic significance in Parkinson's disease (PD). This motor anomaly is dissected within the context of the broader clinical spectrum of PD symptoms, emphasizing its importance alongside its cardinal symptoms. This case report underscores the importance of accurate clinical assessment especially thorough neurological evaluation in discerning hallux hypertonia, potentially enabling early disease recognition and intervention. By synthesizing these clinical insights, we trust that this case report contributes to an enhanced understanding of hypertonia of the hallux as a distinctive clinical presentation in PD fostering improved diagnostic precision.

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.

Botulinum toxin treatment in parkinsonism

Botulinum toxin (BoNT) was approved by the United States Food and Drug Administration (FDA) in 1989 for facial movement disorders and strabismus, but since that time its indications have been expanding beyond neurologic and ophthalmologic disorders. This article is a narrative review of the therapeutic use of BoNT in tremors, dystonia, sialorrhea, bladder and other autonomic symptoms, levodopa-induced dyskinesia and other problems occuring in the setting of parkinsonism. Though FDA approval is lacking for some of these indications, expert experiences have shown that BoNT is often beneficial in this group of patients.

Exploring the Central Mechanisms of Botulinum Toxin in Parkinson's Disease: A Systematic Review from Animal Models to Human Evidence

Botulinum toxin (BoNT) is an effective and safe therapy for the symptomatic treatment of several neurological disturbances. An important line of research has provided numerous pieces of evidence about the mechanisms of action of BoNT in the central nervous system, especially in the context of dystonia and spasticity. However, only a few studies focused on the possible central effects of BoNT in Parkinson's disease (PD). We performed a systematic review to describe and discuss the evidence from studies focused on possible central effects of BoNT in PD animal models and PD patients. To this aim, a literature search in PubMed and SCOPUS was performed in May 2023. The records were screened according to title and abstract by two independent reviewers and relevant articles were selected for full-text review. Most of the papers highlighted by our review report that the intrastriatal administration of BoNT, through local anticholinergic action and the remodulation of striatal compensatory mechanisms secondary to dopaminergic denervation, induces an improvement in motor and non-motor symptoms in the absence of neuronal loss in animal models of PD. In human subjects, the data are scarce: a single neurophysiological study in tremulous PD patients found that the change in tremor severity after peripheral BoNT administration was associated with improved sensory-motor integration and intracortical inhibition measures. Further clinical, neurophysiological, and neuroimaging studies are necessary to clarify the possible central effects of BoNT in PD.

The effectiveness and safety of botulinum toxin injections for the treatment of sialorrhea with Parkinson's disease: a systematic review and meta-analysis

BACKGROUND

Botulinum toxin (BoNT) injection is an important adjunctive method to treat sialorrhea. The purpose of this systematic review was to analyze the effect and safety of BoNT injections in the intervention of sialorrhea with Parkinson's disease (PD).

METHODS

We searched PubMed, Web Of Science (WOS), Scopus, Cochrane CENTRAL, and Embase from inception until April 2022. Randomized controlled trials or randomized crossover trials comparing BoNT with placebo in sialorrhea with PD were eligible. PRISMA guidelines were used to carry out the meta-analysis. The Drooling Severity Frequency Scale (DSFS) score and the number of adverse events (AEs) were the primary and secondary outcomes, respectively. Standardized mean differences (SMDs) and risk differences (RDs) are used to express continuous and categorical outcomes, respectively. Heterogeneity among these studies was evaluated using I2 tests. We used the GRADE tool to assess the certainty of evidence (COE).

RESULTS

Eight articles involving 259 patients compared BoNT injections with a placebo for PD with sialorrhea. This meta-analysis showed a significant reduction in DSFS scores between BoNT injections and placebo (SMD=-0.98; 95% CI, -1.27 to 0.70, p<0.001; COE: high). This meta-analysis showed a significant difference in AEs between BoNT injections and placebo (RD=0.15; 95% CI, 0.05 to 0.24, p=0.002; COE: low).

CONCLUSIONS

The pooled results suggest that BoNT injections have some effect on DSFS scores with sialorrhea caused by PD. There are also mild adverse events, which generally recover within a week or so. The results indicate that BoNT injection is one of the treatments for sialorrhea caused by PD, but we need to pay attention to adverse events. In addition, the follow-up time was extended to observe oral hygiene, ulceration or dental caries, and digestive function.

TRIAL REGISTRATION

Our review protocol was registered on PROSPERO (42021288334).

Recommendations for a paradigm shift in approach to increase the recognition and treatment of sialorrhea in Parkinson's disease

Sialorrhea, or drooling, is defined as excessive saliva accumulation and unwanted loss of saliva from the mouth or over the tongue and into the pharynx. It constitutes one of the most frequent and bothersome complaints of patients with Parkinson's disease (PD), affecting up to 84% of them. Sialorrhea is a distressing and challenging condition that may result in social isolation, embarrassment, depression, skin infections, poor oral health, and aspiration pneumonia. To better understand the burden of sialorrhea on patients with PD, Parkinson's Europe carried out a worldwide patient survey which showed that sialorrhea remains an underrecognized and undertreated issue in patients with PD. This is especially problematic because effective therapeutic options are available. This article presents the results of the Parkinson's Europe Sialorrhea Survey, which were considered by a multidisciplinary panel of experts to provide recommendations for improving the awareness, diagnosis, management, and treatment of sialorrhea in patients with PD. A shift in the treatment paradigm for sialorrhea in patients with PD is emerging. It is essential to better educate patients, family members, caregivers, and healthcare professionals about sialorrhea; to engage all those involved to actively discuss sialorrhea and measure its impact on quality of life; and to recognize the role of botulinum toxin and speech and language therapy as first-line therapies.

Botulinum Toxin Treatment of Motor Disorders in Parkinson Disease-A Systematic Review

This review provides an up-to-date literature account on the efficacy of Botulinum toxin treatment for common motor disorders of Parkinson Disease. The reviewed disorders include the common motor disorders in PD such as tremor, focal foot dystonia, rigidity and freezing of gait (FOG). In the area of Parkinson tremor, two newly described evaluation/injection techniques (Yale method in USA and Western University method in Canada) offer efficacy with low incidence of hand and finger weakness as side effects. Blinded studies conducted on foot dystonia of PD indicate that botulinum toxin injections into toe flexors are efficacious in alleviating this form of dystonia. Small, blinded studies suggest improvement of Parkinson rigidity after botulinum toxin injection; proof of this claim, however, requires information from larger, blinded clinical trials. In FOG, the improvement reported in open label studies could not be substantiated in blinded investigations. However, there is room for further controlled studies that include the proximal lower limb muscles in the injection plan and/or use higher doses of the injected toxin for this indication.

Pharmacological Treatment of Tremor in Parkinson's Disease Revisited

The pathophysiology of Parkinson's disease (PD) tremor remains incompletely understood and there is a lack of clinical trials specifically addressing its pharmacological treatment. Levodopa is the most efficacious drug for most patients and should be used as primary approach to control troublesome tremor. While the efficacy of oral dopamine agonists on PD tremor has been demonstrated in controlled trials, there is no evidence of greater antitremor efficacy compared to levodopa. The magnitude of the antitremor effect of anticholinergics is generally lower than that of levodopa. Due to their adverse effects, anticholinergics have a limited role in selected young and cognitively intact patients. Propranolol may improve resting and action tremor and may be considered as an adjunct in patients with insufficient tremor response to levodopa and this also applies to clozapine, despite its unfavorable adverse effect profile. Treating motor fluctuations with MAO-B and COMT inhibitors, dopamine agonists, amantadine, or on-demand treatments such as subcutaneous or sublingual apomorphine and inhaled levodopa as well as with continuous infusions of levodopa or apomorphine will improve off period tremor episodes. For patients with drug-refractory PD tremor despite levodopa optimization deep brain stimulation and focused ultrasound are first-line considerations. Surgery can also be highly effective for the treatment medication-refractory tremor in selected patients without motor fluctuations. The present review highlights the clinical essentials of parkinsonian tremor, critically examines available trial data on the effects of medication and surgical approaches and provides guidance for the choice of treatments to control PD tremor in clinical practice.

User-Centered Design Methodologies for the Prototype Development of a Smart Harness and Related System to Provide Haptic Cues to Persons with Parkinson's Disease

This paper describes the second part of the PASSO (Parkinson smart sensory cues for older users) project, which designs and tests an innovative haptic biofeedback system based on a wireless body sensor network using a smartphone and different smartwatches specifically designed to rehabilitate postural disturbances in persons with Parkinson's disease. According to the scientific literature on the use of smart devices to transmit sensory cues, vibrotactile feedback (particularly on the trunk) seems promising for improving people's gait and posture performance; they have been used in different environments and are well accepted by users. In the PASSO project, we designed and developed a wearable device and a related system to transmit vibrations to a person's body to improve posture and combat impairments like Pisa syndrome and camptocormia. Specifically, this paper describes the methodologies and strategies used to design, develop, and test wearable prototypes and the mHealth system. The results allowed a multidisciplinary comparison among the solutions, which led to prototypes with a high degree of usability, wearability, accessibility, and effectiveness. This mHealth system is now being used in pilot trials with subjects with Parkinson's disease to verify its feasibility among patients.

Striatal hand deformities in Parkinson's disease ‐ hand surgical perspectives

Background

The knowledge about striatal hand deformities (SHD) in Parkinson's disease (PD), has recently increased but need more attention due to their early impact on dexterity. The focus of clinical studies has been on the staging of SHD severity and neurological features. However, a hand surgical perspective has not been considered.

Objectives

Our purpose was to examine SHD in patients with PD using hand surgical assessment methods and the recommended staging of SHD.

Methods

In this observational study, a specialist in neurological physiotherapy examined 100 consecutive PD patients and identified 35 with suspected SHD, who were then examined by two hand surgeons. Their hands were clinically evaluated for severity of SHD, according to a previous proposed staging, focusing on metacarpophalangeal (MCP) joint flexion, presence of intrinsic and extrinsic tightness, as well as other hand deformities.

Results

Three kinds of deformities were identified among 35 included patients: surgical diagnoses unrelated to PD (n = 5), SHD (n = 23), and PD related hand deformities with increased extrinsic tightness (n = 10); three of these 10 patients had also contralateral SHD, thus are included in SHD group. In addition to previously described MCP joint flexion, swan neck deformity and z‐thumb deformity, we found in most hands finger “clefting,” abduction of the little finger and/or an increased intrinsic tightness, indicating pathology of intrinsic muscles of the hand involved in SHD.

Conclusions

SHD diagnosed with a modified staging method, including features of intrinsic and extrinsic hand deformities, should be considered in PD to implement early and more accurate treatment.