Pain perception, pain drug therapy and health status in patients with Parkinson's disease

Health-related quality of life in Parkinson's disease: systematic review and meta-analysis of EuroQol (EQ-5D) utility scores

INTRODUCTION

Evaluating the Health-related quality of life (HRQoL) of individuals with Parkinson's disease (PD) holds significant importance in clinical and research settings. The EQ-5D is a widely recognized tool for comprehensive measurement of HRQoL using utility values. This study aims to systematically review and synthesize EQ-5D utility values from existing literature on patients with PD and their caregivers.

METHODS

We conducted a systematic search for studies that provided EQ-5D utility scores for patients with PD, using PubMed-Medline, Scopus, and Embase and selected the studies. The selected studies underwent systematic review, including an assessment of their quality. We performed a meta-analysis using a random-effect model and conducted a meta-regression analysis to investigate sources of heterogeneity among the studies.

RESULTS

The search result of 13,417 articles that were reviewed, 130 studies with 33,914 participants were selected for systematic review, and 79 studies were included for meta-analysis. The pooled EQ-5D utility values and visual analog score (VAS) among PD were 62.72% (60.53-64.93, I2 = 99.56%) and 0.60 (0.55-0.65, I2 = 99.81%), respectively. The pooled scores for caregivers' EQ-VAS and EQ-5D utility were 70.10% (63.99-76.20, I2 = 98.25%) and 0.71 (0.61-0.81, I2 = 94.88%), respectively. Disease duration (P < 0.05) showed a negative correlation with EQ-5D utility values on meta-regression.

CONCLUSION

The pooled utility values of PD and their caregivers help to understand their HRQoL and aid in conducting health economics research. The negative association between disease duration and utility values highlights the evolving nature of HRQoL challenges, suggesting the need for appropriate long-term disease management.

Sex Differences in Parkinson’s Disease: From Bench to Bedside

Background: Parkinson’s disease (PD) is the second most common neurodegenerative disorder after Alzheimer’s disease and gender differences have been described on several aspects of PD. In the present commentary, we aimed to collect and discuss the currently available evidence on gender differences in PD regarding biomarkers, genetic factors, motor and non-motor symptoms, therapeutic management (including pharmacological and surgical treatment) as well as preclinical studies. Methods: A systematic literature review was performed by searching the Pubmed and Scopus databases with the search strings “biomarkers”, “deep brain stimulation”, “female”, “gender”, “genetic”, “levodopa”, “men”, “male”, “motor symptoms”, “non-motor symptoms”, “Parkinson disease”, “sex”, “surgery”, and “women”. Results: The present review confirms the existence of differences between men and women in Parkinson Disease, pointing out new information regarding evidence from animal models, genetic factors, biomarkers, clinical features and pharmacological and surgical treatment. Conclusions: The overall goal is to acquire new informations about sex and gender differences in Parkinson Disease, in order to develop tailored intervetions.

Probiotics synergized with conventional regimen in managing Parkinson's disease

Parkinson's disease (PD) is mainly managed by pharmacological therapy (e.g., Benserazide and dopamine agonists). However, prolonged use of these drugs would gradually diminish their dopaminergic effect. Gut dysbiosis was observed in some patients with PD, suggesting close association between the gut microbiome and PD. Probiotics modulate the host's gut microbiota beneficially. A 3-month randomized, double-blind, placebo-controlled clinical trial was conducted to investigate the beneficial effect of probiotic co-administration in patients with PD. Eighty-two PD patients were recruited and randomly divided into probiotic [n = 48; Bifidobacterium animalis subsp. lactis Probio-M8 (Probio-M8), Benserazide, dopamine agonists] and placebo (n = 34; placebo, Benserazide, dopamine agonists) groups. Finally, 45 and 29 patients from Probio-M8 and placebo groups provided complete fecal and serum samples for further omics analysis, respectively. The results showed that Probio-M8 co-administration conferred added benefits by improving sleep quality, alleviating anxiety, and gastrointestinal symptoms. Metagenomic analysis showed that, after the intervention, there were significantly more species-level genome bins (SGBs) of Bifidobacterium animalis, Ruminococcaceae, and Lachnospira, while less Lactobacillus fermentum and Klebsiella oxytoca in Probio-M8 group (P < 0.05). Interestingly, Lactobacillus fermentum correlated positively with the scores of UPDRS-III, HAMA, HAMD-17, and negatively with MMSE. Klebsiella oxytoca correlated negatively with feces hardness. Moreover, co-administering Probio-M8 increased SGBs involved in tryptophan degradation, gamma-aminobutyric acid, short-chain fatty acids, and secondary bile acid biosynthesis, as well as serum acetic acid and dopamine levels (P < 0.05). Taken together, Probio-M8 synergized with the conventional regimen and strengthened the clinical efficacy in managing PD, accompanied by modifications of the host's gut microbiome, gut microbial metabolic potential, and serum metabolites.

Perspective: cell death mechanisms and early diagnosis as precondition for disease modification in Parkinson's disease: are we on the right track?

INTRODUCTION

Current research paradigms on biomarkers for chronic neurodegenerative diseases, such as Parkinson's disease, focus on identification of reliable, easy-to-apply tools for diagnostic screening and progression assessment.

AREAS COVERED

This perspective discusses possible misconceptions of biomarker research in chronic neurodegeneration from a clinician's view based on a not systematic literature search. Multifactorial disease triggers, heterogeneity of symptom and their progression are main reasons for the still missing availability of biomarkers.

EXPERT OPINION

Onset of chronic neurodegenerative disease entities may probably result from a decompensated endogenous repair machinery in the central nervous system, for example the neogenin receptor associated repulsive guidance molecule pathway. Future clinical research is warranted on these repair structures and aim to identify markers for the imbalance between damage and repair, which hypothetically contributes to generation of disease. An assignment to a specific chronic neurodegenerative disease entity probably appears to be secondary. Decryption of probable molecular signals of an impaired repair potential will enable an earlier diagnosis, better monitoring of disease progress and of treatment response. This concept will hopefully provide better preconditions for prevention, cure or therapeutic beneficial disease modification. These unmet therapeutic needs may be achieved for example via antagonism of repulsive guidance molecule A.

Pain Assessment in Indian Parkinson's Disease Patients Using King's Parkinson's Disease Pain Scale

Background:

Pain is a common symptom in Parkinson's disease (PD) patients. Scales to rate pain in PD are marred by several flaws, either not being available in other languages or not specific for PD.

Objectives:

To assess the frequency of pain among bilingual Indian PD patients using “King's Parkinson's disease pain scale” (KPPS) and to validate it.

Methods:

We randomly administered KPPS in Hindi/English to all consecutive bilingual persons with PD. The results were appropriately analyzed.

Results:

A total of 119 PD patients were enrolled with a mean age of 64.34 (± 9.57) years. Median Hoehn and Yahr stage was 2 (42.85%). Pain was present in 62 (52.1%) PD patients. The most common type was musculoskeletal (74.19%). The mean total KPPS score was 16.02 ± 10.57. KPPS score was significantly higher in women and correlated positively with unified Parkinson's disease rating scale (UPDRS) part 2 and 4 scores (r = 0.27 and r = 0.25). Risk factors for pain were female gender, higher H and Y stage, total UPDRS score, and individual UPDRS part 3 and 4 scores. Difficulty falling asleep (P = 0.01), frequent awakenings (P = 0.01), diminished smell sensation (P = 0.003), diminished speech volume (P = 0.02), gait freezing (P = 0.03), and falls (P = 0.001) correlated with the presence of pain. The interclass correlation coefficient between the Hindi and English versions of KPPS was 0.835, while Bland–Altman analysis showed 96.7% agreement suggesting excellent correlation and validation.

Conclusions:

KPPS is an easy tool for characterization, scoring, and follow-up of pain in PD patients. The Hindi version has good agreement with the original English version.

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.

Activated Schwann cells and increased inflammatory cytokines IL-1β, IL-6, and TNF-α in patients' sural nerve are lack of tight relationship with specific sensory disturbances in Parkinson's disease

Aims

Neuroinflammation is one of the most important processes in the pathogenesis of Parkinson's disease (PD). Sensory disturbances are common in patients with PD, but the underlying pathophysiological mechanisms remain unknown. This study aimed to characterize the activation of Schwann cells (SCs) and the increase of expression of inflammatory cytokines IL‐1β, IL‐6, and TNF‐α in the sural nerve of PD, and further explore whether peripheral nerve inflammation is the cause of PD sensory disturbances.

Methods

A total of 14 patients with PD (including 5 with sensory disturbances and 9 without sensory disturbances) and 6 controls were included. The excitation and conduction function of sural nerve was detected by sural nerve electrophysiological examination. With sural nerve biopsy samples, ultrastructural changes of sural nerve were observed by electron microscopy; Schwann cell biomarker glial fibrillary acid protein (GFAP) and inflammatory cytokines including interleukin‐1beta (IL‐1β), interleukin 6 (IL‐6), and tumor necrosis factor‐alpha (TNF‐α) were detected by immunohistochemistry, and the outcome of immunostaining slice was semiquantitatively counted; double immunofluorescence was used to identify the locus immunoreactive for inflammatory cytokines.

Results

Compared with healthy controls, nerve conduction velocity (NCV) slowed down and sensory nerve action potential (SNAP) amplitude decreased in PD patients, accompanied by axonal degeneration and demyelinating lesions, and expression of GFAP and inflammatory cytokines was increased. Inflammatory cytokines were significantly colocalized with GFAP and slightly colocalized with NF. These indicators did not differ significantly between PD patients with and without sensory disturbances.

Conclusion

Our study results suggest that peripheral sensory nerve injury exists in PD patients, accompanied by Schwann cell activation and inflammation, thus demonstrate peripheral nerve inflammation participates in the pathophysiological process of PD but it is not necessarily related to the patient's sensory disturbance.

Parkinson disease: A systemic review of pain sensitivities and its association with clinical pain and response to dopaminergic stimulation

Patients with Parkinson disease (PD) experience hyperalgesia on evoked pain sensitivity testing, although the relationship of this with persistent pain in PD is less certain. Studies examining this have generated contradictory findings. Further, the role of dopaminergic deficiency as an underlying substrate for hyperalgesia is controversial. We report the results of meta-analyses of the PD pain sensitivity literature in an attempt to answer these questions. We identified 429 records, of which ten articles compared pain sensitivity between PD patients that experienced clinical pain (PDP) to those who did not (PDNP), and twenty studies that examined the effect of dopaminergic medications on pain sensitivity in PD patients. PDP patients experienced a moderate increase in pain sensitivity, had more severe disease, required higher dosages of medication, and were more likely to be female when compared to those PDNP patients. PD patients also had reduced pain sensitivity when tested on dopaminergic medications compared to when they were not on medications. Overall, the results of this systematic review and meta-analysis supports the hypothesis that hyperalgesia contributes to clinical pain in PD, and that the underlying mechanism may be dopaminergically driven.

Distribution and impact on quality of life of the pain modalities assessed by the King's Parkinson's disease pain scale

In Parkinson’s disease, pain is a prevalent and complex symptom of diverse origin. King’s Parkinson’s disease pain scale, assesses different pain syndromes, thus allowing exploration of its differential prevalence and influence on the health-related quality of life of patients. Post hoc study 178 patients and 83 matched controls participating in the King’s Parkinson’s disease pain scale validation study were used. For determining the respective distribution, King’s Parkinson’s disease pain scale items and domains scores = 0 meant absence and ≥1 presence of the symptom. The regular scores were used for the other analyses. Health-related quality of lifewas evaluated with EQ-5D-3L and PDQ-8 questionnaires. Parkinson’s disease patients experienced more pain modalities than controls. In patients, Pain around joints (King’s Parkinson’s disease pain scale item 1) and Pain while turning in bed (item 8) were the most prevalent types of pain, whereas Burning mouth syndrome (item 11) and Pain due to grinding teeth (item 10) showed the lowest frequency. The total number of experienced pain modalities closely correlated with the PDQ-8 index, but not with other variables. For all pain types except Pain around joints (item 1) and pain related to Periodic leg movements/RLS (item 7), patients with pain had significantly worse health-related quality of life. The influence of pain, as a whole, on the health-related quality of life was not remarkable after adjustment by other variables. When the particular types of pain were considered, adjusted by sex, age, and Parkinson’s disease duration, pain determinants were different for EQ-5D-3L and PDQ-8. King’s Parkinson’s disease pain scale allows exploring the distribution of the diverse syndromic pain occurring in Parkinson’s disease and its association with health-related quality of life.

Researchers confirm that the pain experienced by patients with Parkinson disease (PD) is a key determinant of health-related quality of life. Pain is a common non-motor symptom that is often underacknowledged and undertreated. Using data from the recently validated pain scale for PD, Pablo Martinez-Martin (Carlos III Institute of Health in Madrid, Spain) and colleagues explored the impact of specific pain modalities on patients’ quality of life. They found that patients with PD reported experiencing twice as many types of pain than controls, with pain around the joints and pain while moving in bed being the most prevalent. Furthermore, there was a close correlation between the number of experienced pain modalities and quality of life as evaluated with the PD questionnaire PDQ-8. Understanding the different types of pain in PD will aid the provision of effective pain relief and greatly improve patients’wellbeing.

Rating Scales for Pain in Parkinson's Disease: Critique and Recommendations

BACKGROUND

We aimed at critically appraising the clinimetric properties of existing pain scales or questionnaires and to give recommendations for their use in Parkinson's disease (PD).

METHODS

Clinimetric properties of pain scales used in PD were systematically evaluated. A scale was classified as 'recommended' if was used in PD, showed adequate clinimetric properties, and had been used by investigators other than the original developers; as 'suggested' if it was used in PD and fulfilled only one other criterion; and as 'listed' if it was used in PD but did not meet the other criteria. Only scales rating pain intensity or for syndromic classification were assessed.

RESULTS

Eleven of the 34 scales initially considered fulfilled inclusion criteria. Among the scales rating pain intensity, the "Brief Pain Inventory short form," "McGill Pain Questionnaire short and long forms," "Neuropathic Pain Symptoms Inventory," "11-point Numeric Rating Scale," "10-cm Visual Analog Scale," and "Pain-O-Meter" were "recommended with caution" because of lack of clinimetric data in PD, whereas the "King's PD Pain Scale" was "recommended." Among scales for pain syndromic classification, the "DN4" was "recommended with caution" because of lack of clinimetric data in PD; the "Leeds Assessment of Neuropathic Symptoms and Signs," "Pain-DETECT," and the "King's PD Pain Scale" were "suggested."

CONCLUSIONS

King's PD pain scale can be recommended for the assessment of pain intensity in PD. Syndromic classification of pain in PD may be achieved by the DN4, but clinimetric data in PD are needed for this scale.

Nondopaminergic therapy of motor and nonmotor symptoms in Parkinson's disease: a clinician's perspective

Patients with Parkinson's disease suffer from impaired motor behavior due to the dopaminergic striatal deficit and nonmotor symptoms, which also result from nondopaminergic neuronal death. This review provides a personal opinion on treatment strategies for symptoms, resulting at least partially from nondopaminergic neurodegeneration, and on therapeutic modulation of dopaminergic neurotransmission. Patient-tailored treatment regimes on the basis of an individual risk benefit ratio as essential precondition try to balance all these symptoms. Individually varying heterogeneity of symptoms, nonlinear disease progression, treatment response, acceptance, tolerability and safety of applied therapies demand a close, consistent relationship between patient and treating physician. Daily maintenance of patients does not ask for too detailed treatment guidelines.

Pain in Parkinson's Disease: A Cross-Sectional Study of Its Prevalence, Types, and Relationship to Depression and Quality of Life

Pain is an important and distressing symptom in Parkinson's disease (PD). Our aim was to determine the prevalence of pain, its various types and characteristics, as well as its impact on depression and quality of life (QoL) in patients with PD. How pain differs in early- and advanced-stage PD and male and female PD patients was of special interest. One hundred PD patients on dopaminergic medications had a neurological examination and participated in a structured interview on pain characteristics and completed standardized questionnaires. A total of 76% of the patients had pain. The following types of pain were present: musculoskeletal pain accounted for 41% of the total pain, dystonic pain for 17%, central neuropathic pain for 22%, radicular pain for 27%, and other pains (non-radicular low back pain, arthritic, and visceral pain) made up 24%. One type of pain affected 29% of all the subjects, two types 35%, three types 10%, and four types of pain were reported by 2%. All types of pain were more prevalent in advanced-stage PD subjects than in early-stage PD subjects, except for arthritic pain (subclassified under"other pain"). The frequency and intensity of actual, average, and worst experienced pain were significantly more severe in advanced-stage subjects. PD subjects with general pain and in advanced stages were more depressed and had poorer QoL. Depression correlated with worst pain in the last 24 hours and with pain periodicity (the worst depression score in patients with constant pain). QoL correlated with average pain in the last 7 days. Pain is a frequent problem in PD patients, and it worsens during the course of the disease.

Sensory aspects of movement disorders

Movement disorders, which include disorders such as Parkinson's disease, dystonia, Tourette's syndrome, restless legs syndrome, and akathisia, have traditionally been considered to be disorders of impaired motor control resulting predominantly from dysfunction of the basal ganglia. This notion has been revised largely because of increasing recognition of associated behavioural, psychiatric, autonomic, and other non-motor symptoms. The sensory aspects of movement disorders include intrinsic sensory abnormalities and the effects of external sensory input on the underlying motor abnormality. The basal ganglia, cerebellum, thalamus, and their connections, coupled with altered sensory input, seem to play a key part in abnormal sensorimotor integration. However, more investigation into the phenomenology and physiological basis of sensory abnormalities, and about the role of the basal ganglia, cerebellum, and related structures in somatosensory processing, and its effect on motor control, is needed.