An overview of pain in Parkinson's disease

Efficacy of deep brain stimulation of the subthalamic nucleus versus globus pallidus internus on sensory complaints

Pain control after deep brain stimulation (DBS) in Parkinson's disease (PD) remains unclear. Following six months, subthalamic (STN)-DBS reduced sensory complaints related to parkinsonism and bodily discomfort, increasing central beta-endorphin level. Pallidal GPi-DBS decreased bodily discomfort and beta-endorphin levels. Unexplained pain by other conditions and bodily discomfort were negatively correlated with beta-endorphin levels. Thus, DBS regulates central opioids, and prioritizing STN is important for PD patients with significant sensory complications.

Safety and tolerability of long-term apomorphine infusion in advanced Parkinson's disease: an Indian multi-center (APO-IND) experience

Advanced Parkinson's Disease (APD) is complicated by the emergence of motor and non-motor fluctuations, which are initially predictable and eventually become unpredictable, in part due to erratic gastric absorption and short half of oral levodopa. Attempts to manage such fluctuations with oral dopaminergic drugs often lead to disabling dyskinesias. Continuous Subcutaneous Apomorphine Infusion (CSAI), despite being approved for the treatment of APD since 1993, was approved in India only in 2019. We studied the safety, tolerability and efficacy of CSAI in Indian patients with APD in a registry design to raise local awareness of this important treatment. We conducted a prospective registry-based observational audit at 10 centers across different states of India. Patients with APD, not responding to or with significant side effects from oral dopaminergic therapy, were assessed at baseline and at month 6 and 12 following CSAI infusion. Fifty-one patients completed the study, CSAI significantly reduced the functional impact of dyskinesia (p < 0.01 at 6 months and p < 0.001 at 12 months). There was a significant improvement in the OFF-state from baseline (p < 0.01 at 6 months and p < 0.001 at 12 months) No discernible side effects were observed apart from mild site reaction (n = 7), nausea (n = 7) skin nodules (n = 2). CSAI demonstrated safety, efficacy, tolerability and improved quality of life in patients with APD, as shown in previous studies. Our study highlighted current existing inequalities in treatment availability, lack of awareness, knowledge gap, affordability and cost remains a concern regarding apomorphine use in Indian PD population.

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.

Therapeutic Approaches to Non-Motor Symptoms of Parkinson's Disease: A Current Update on Preclinical Evidence

Despite being classified as a movement disorder, Parkinson's disease (PD) is characterized by a wide range of non-motor symptoms that significantly affect the patients' quality of life. However, clear evidence-based therapy recommendations for non-motor symptoms of PD are uncommon. Animal models of PD have previously been shown to be useful for advancing the knowledge and treatment of motor symptoms. However, these models may provide insight into and assess therapies for non-motor symptoms in PD. This paper highlights non-motor symptoms in preclinical models of PD and the current position regarding preclinical therapeutic approaches for these non-motor symptoms. This information may be relevant for designing future preclinical investigations of therapies for nonmotor symptoms in PD.

Orofacial pain and dysfunction in patients with Parkinson's disease: A scoping review

BACKGROUND

Parkinson's disease (PD) is commonly known as a disorder that affects the smooth performance of body movements. In addition to the motor impairments, patients with PD often experience pain. Both motor impairments and pain can occur throughout the body, hence including the orofacial region. However, currently, there is a lack of knowledge on the orofacial manifestations. Since orofacial pain and dysfunction can, amongst others, reduce the quality of life of patients with PD, it is important to explore the prevalence of these symptoms in the PD population.

OBJECTIVE

To provide a broad overview of the relevant literature on orofacial pain and dysfunction in patients with PD. Furthermore, we aim to generate hypotheses for future research on this topic.

DATABASES AND DATA TREATMENT

A literature search (in PubMed, Embase.com, Web of Science [Core collection], and Cochrane Library) was performed on 20 January 2022, in collaboration with a medical librarian. In total, 7180 articles were found, of which 50 were finally included in this scoping review.

RESULTS

In the included studies, pain (e.g. orofacial pain (N = 2) and temporomandibular disorder pain (N = 2)), orofacial motor dysfunction (e.g. limited jaw movements (N = 10), reduced maximum muscle output (N = 3), chewing difficulties (N = 9), unspecified TMD (N = 3), sensory disturbances (N = 1)), and bruxism (N = 3) were observed more often in patients with PD than in healthy controls.

CONCLUSION

Patients with PD experience more pain in the orofacial area and more dysfunction of the masticatory system than their healthy peers.

SIGNIFICANCE

This scoping review can increase health care providers' awareness of the problems that can be encountered in the orofacial area of PD patients, especially pain syndromes also occur in the orofacial region and not only in the extremities. Besides, dysfunction of the orofacial area is elaborated in this scoping review, which helps to understand that this limits PD patients' quality of life. Further, the outcomes of this scoping review can assist in encouraging collaboration between medicine and dentistry. Finally, this scoping review suggests new research areas, based on the gaps identified in the current literature on this topic. Ultimately, this will improve individualized strategies for reducing orofacial pain and/or dysfunction in PD patients.

Chiropractic care of Parkinson's disease and deformity

Parkinson's disease (PD) is a progressive neurological disease characterized by muscle stiffness, tremor, slowness of movement, and difficulties with posture and walking. Muscle and joint pain are frequent non-motor symptoms of PD. Pain associated with PD is mainly caused by a combination of truncal dystonia, stooped posture, and muscle rigidity. However, PD deformities were rarely discussed in the literature. A 68-year-old Asian female with PD treated with Levodopa for six years complained of progressive neck pain, contractures, and subluxation of both hands in the last two years. A positron emission tomography (PET) scan revealed decreased rostrocaudal gradient uptake in both posterior putamen. After 9 months of multimodal chiropractic rehabilitation, the patient had significant improvement in symptoms, including pain resolution as per the numeric rating scale and physical and mental improvement as per the PD questionnaire. Radiographic measurement showed significantly improved postural alignment and stability. Measurement of joint motion and angles showed an improvement in hand deformity. Although PD is a neurodegenerative disease that is not curable, multimodal rehabilitation may improve neurological and musculoskeletal functions by inducing proprioceptive balance, motor strength, and joint movement. The current study may illustrate multimodal rehabilitation addressing orthopedic deformity associated with symptoms in a PD patient.

The impact of nonmotor symptom burden on sexual function

Sexual dysfunction (SD) is defined as a combination of reduction in libido, and problems with a person's ability to have sex. It is a frequent but neglected and poorly recognized nonmotor symptom (NMS) in Parkinson's disease (PD) which correlates with reduced quality of life (QoL). Hypersexuality forms another spectrum of SD and is an impulse control disorder (ICD) of behavior, which also affects the sexual desires of people with Parkinson's (PwP) and impacts their partner, family, and QoL. NMS occur in various forms and represents a range of symptoms, from cognitive dysfunction to pain and SD, and this chapter explores the relationship of comorbid NMS with SD and also how NMS, motor symptoms, and hypersexuality experienced by patients may impact sexual function in people with Parkinson's (PwP).

Antidepressants Effects on Pain in Parkinson Disease: A Systematic Review

OBJECTIVE

Pain in Parkinson disease (PD) is complex as this symptom can be multifactorial in origin because deficits in dopaminergic but also other neurotransmitters are involved. Pain and depression are increasingly recognized to have clinical importance for the quality of life of people living with PD. This systematic review aims to summarize the existing evidence on the potential benefit of using prescribed antidepressants for decreasing or controlling pain associated with PD.

METHODS

PubMed databases were searched for relevant studies using keywords and our exclusion/inclusion criteria and targeting only randomized placebo-controlled trials for antidepressants in PD.

RESULTS

After screening 108 articles, only 3 focused articles were analyzed. Two of the included studies reported were on nortriptyline and paroxetine antidepressants. Unfortunately, included studies did not align in their outcome measures and did not directly compare the drug groups against each other or the placebo. Therefore, the complex nature of the unaligned outcome measures is inadequate for interpreting the efficacy of antidepressants in treating pain symptoms in PD. The third study focused solely on observing the effects of duloxetine but showed no favorable effects of this drug on pain.

CONCLUSIONS

Prospective studies with a direct comparison of antidepressants and placebo should be conducted, focusing on pain-related scales and questions to understand further the role of antidepressants in treating pain in PD.

Chiropractic care for low back pain, gait and posture in a patient with Parkinson's disease: a case report and brief review

Parkinson's disease (PD) is a progressive neurological disorder with cardinal motor features of tremor, bradykinesia, muscle rigidity, impaired gait and posture. Muscular pain or arthralgia is a common non-motor symptom in PD. The PD-related pain is probably attributed to a combination of altered posture, abnormal muscle tone, and truncal dystonia. A 59-year-old male taxi-driver with PD treated with levodopa for 18 months complained of progressive low back pain and gait difficulties that prevented him from normal activities in the past 2 months. Magnetic resonance imaging showed degenerative disc disease with multiple levels of bulging discs in the lumbar spine. After 35 chiropractic sessions, there was a significant improvement in various aspects of well-being, including pain resolution measured by a numeric rating scale, physical and mental improvement measured by the Parkinson's Disease Questionnaire, gait stability depicted by gait cyclogram, and better postural alignment and stability assessed by radiographic parameters. The current study may serve as an example of spinal manipulation showing the potential to address gait and posture problems associated with pain in a patient with PD. Aging changes in the muscles, bones and joints may accompany PD. Although PD itself is an incurable neurodegenerative disease, functional capacity of the musculoskeletal system can be enhanced by different types of manual therapy, by means of improving muscle strength, joint mobility, and postural balance. The actual duration in sustaining improved outcomes following a course of manipulative intervention remains to be determined.

Predictors of Global Non-Motor Symptoms Burden Progression in Parkinson's Disease. Results from the COPPADIS Cohort at 2-Year Follow-Up

Background and Objective: Non-motor symptoms (NMS) progress in different ways between Parkinson's disease (PD) patients. The aim of the present study was to (1) analyze the change in global NMS burden in a PD cohort after a 2-year follow-up, (2) to compare the changes with a control group, and (3) to identify predictors of global NMS burden progression in the PD group. Material and Methods: PD patients and controls, recruited from 35 centers of Spain from the COPPADIS cohort from January 2016 to November 2017, were followed-up with after 2 years. The Non-Motor Symptoms Scale (NMSS) was administered at baseline (V0) and at 24 months ± 1 month (V2). Linear regression models were used for determining predictive factors of global NMS burden progression (NMSS total score change from V0 to V2 as dependent variable). Results: After the 2-year follow-up, the mean NMS burden (NMSS total score) significantly increased in PD patients by 18.8% (from 45.08 ± 37.62 to 53.55 ± 42.28; p < 0.0001; N = 501; 60.2% males, mean age 62.59 ± 8.91) compared to no change observed in controls (from 14.74 ± 18.72 to 14.65 ± 21.82; p = 0.428; N = 122; 49.5% males, mean age 60.99 ± 8.32) (p < 0.0001). NMSS total score at baseline (β = -0.52), change from V0 to V2 in PDSS (Parkinson's Disease Sleep Scale) (β = -0.34), and change from V0 to V2 in NPI (Neuropsychiatric Inventory) (β = 0.25) provided the highest contributions to the model (adjusted R-squared 0.41; Durbin-Watson test = 1.865). Conclusions: Global NMS burden demonstrates short-term progression in PD patients but not in controls and identifies worsening sleep problems and neuropsychiatric symptoms as significant independent predictors of this NMS progression.

Is dopaminergic medication dose associated with self-reported bruxism in Parkinson's disease? A cross-sectional, questionnaire-based study

OBJECTIVES

It is not clear whether dopaminergic medication influences bruxism behaviour in patients with Parkinson's disease (PD). Therefore, the aims are to investigate (i) the prevalence of possible (i.e., self-reported) bruxism (sleep and awake) in PD patients, and (ii) whether the use of dopaminergic medication and other factors (viz., demographic characteristics, PD-related factors, and possible consequences of bruxism) are associated with possible bruxism (sleep or awake).

MATERIALS AND METHODS

This study concerns a secondary analysis of an earlier published study. Three hundred ninety-five PD patients (67.9 ± 8.6 years of age; 58.7% males) were included. The levodopa equivalent daily dosage (LEDD) was used as a measure of the dopaminergic medication level. Subsequently, a logistic regression analysis was performed for the dependent variables 'awake bruxism' and 'sleep bruxism', with the following predictors: gender, age, LEDD, time since PD diagnosis, temporomandibular disorder (TMD) pain, jaw locks, and tooth wear.

RESULTS

The prevalence of possible awake and sleep bruxism was 46.0% and 24.3%, respectively. Awake bruxism was associated with sleep bruxism (OR = 8.52; 95% CI 3.56-20.40), TMD pain (OR = 4.51; 95% CI 2.31-8.79), and tooth wear (OR = 1.87; 95% CI 1.02-3.43). Sleep bruxism was associated with tooth wear (OR = 12.49; 95% CI 4.97-31.38) and awake bruxism (OR = 9.48; 95% CI 4.24-21.19). Dopaminergic medication dose was not associated with awake bruxism (OR = 1.0; 95% CI 0.99-1.00) or sleep bruxism (OR = 1.0; 95% CI 0.99-1.00).

CONCLUSION

Bruxism is a common condition in PD patients, but is not associated with the dopaminergic medication dose.

CLINICAL RELEVANCE

(Oral) health care providers should be alerted about the possibility of sleep and awake bruxism activity in PD patients, along with this activity's possible negative health outcomes (viz., TMD pain, tooth wear).

Therapeutic Applications of Botulinum Neurotoxin for Autonomic Symptoms in Parkinson's Disease: An Updated Review

Parkinson's disease is the most common age-related motoric neurodegenerative disease. In addition to the cardinal motor symptoms of tremor, rigidity, bradykinesia, and postural instability, there are numerous non-motor symptoms as well. Among the non-motor symptoms, autonomic nervous system dysfunction is common. Autonomic symptoms associated with Parkinson's disease include sialorrhea, hyperhidrosis, gastrointestinal dysfunction, and urinary dysfunction. Botulinum neurotoxin has been shown to potentially improve these autonomic symptoms. In this review, the varied uses of botulinum neurotoxin for autonomic dysfunction in Parkinson's disease are discussed. This review also includes discussion of some additional indications for the use of botulinum neurotoxin in Parkinson's disease, including pain.