Pain in monogenic Parkinson's disease: a comprehensive review

Pain, a challenging symptom experienced by individuals diagnosed with Parkinson's disease (PD), still lacks a comprehensive understanding of its underlying pathophysiological mechanisms. A systematic investigation of its prevalence and impact on the quality of life in patients affected by monogenic forms of PD has yet to be undertaken. This comprehensive review aims to provide an overview of the association between pain and monogenic forms of PD, specifically focusing on pathogenic variants in SNCA, PRKN, PINK1, PARK7, LRRK2, GBA1, VPS35, ATP13A2, DNAJC6, FBXO7, and SYNJ1. Sixty-three articles discussing pain associated with monogenic PD were identified and analyzed. The included studies exhibited significant heterogeneity in design, sample size, and pain outcome measures. Nonetheless, the findings of this review suggest that patients with monogenic PD may experience specific types of pain depending on the pathogenic variant present, distinguishing them from non-carriers. For instance, individuals with SNCA pathogenic variants have reported painful dystonia, lower extremity pain, dorsal pain, and upper back pain. However, these observations are primarily based on case reports with unclear prevalence. Painful lower limb dystonia and lower back pain are prominent symptoms in PRKN carriers. A continual correlation has been noted between LRRK2 mutations and the emergence of pain, though the conflicting research outcomes pose challenges in reaching definitive conclusions. Individuals with PINK1 mutation carriers also frequently report experiencing pain. Pain has been frequently reported as an initial symptom and the most troublesome one in GBA1-PD patients compared to those with idiopathic PD. The evidence regarding pain in ATP13A2, PARK7, VPS35, DNAJC6, FBXO7, and SYNJ1pathogenic variants is limited and insufficient. The potential linkage between genetic profiles and pain outcomes holds promising clinical implications, allowing for the potential stratification of patients in clinical trials and the development of personalized treatments for pain in monogenic PD. In conclusion, this review underscores the need for further research to unravel the intricate relationship between pain and monogenic forms of PD. Standardized methodologies, larger sample sizes, and longitudinal studies are essential to elucidate the underlying mechanisms and develop targeted therapeutic interventions for pain management in individuals with monogenic PD.

Rapid Eye Movement Sleep Behavior Disorder in Parkinson's Disease: A Survey-Based Study

OBJECTIVE

To characterize Parkinson's disease (PD) symptoms based on the presence, onset time, and severity of rapid eye movement sleep behavior disorder (RBD) and their association with impulse control disorders (ICD).

BACKGROUND

RBD is a frequent non-motor symptom in PD, usually described as prodromal. The severity of RBD according to the start time and its relationship with ICD in PD needs further clarification.

METHODS

A survey-based study was performed to determine the presence of RBD symptoms, their severity, and the temporal relationship with the PD onset. The survey included RBD1Q, the Mayo Sleep, and the RBDQ-HK questionnaires and questions about clinical characteristics, including ICD. Only PD patients with care partners spending night hours in the same room were included.

RESULTS

410 PD patients were included: 206 with RBD (50.2%) and 204 non-RBD (49.8%). The PD-RBD patients were younger and their daily levodopa dose was higher than the non-RBD group. Most of these patients developed RBD symptoms after the onset of clinical PD were younger at motor symptom onset and had higher scores in the hallucinations and psychosis subsection of MDS-UPDRS-I. RBD group had a more severe non-motor phenotype, including more ICD than those without RBD, mainly due to higher compulsive eating.

CONCLUSIONS

In our study, most patients recognized RBD symptoms after the onset of the PD motor symptoms and the clinical features of PD with and without RBD were distinctive, supporting the hypothesis that PD-RBD might represent a variant pattern of neurodegeneration.

Clinical correlates of Fear of Falling in Progressive Supranuclear Palsy and Multiple System Atrophy

BACKGROUND

Clinical correlates of fear of falling (FoF) are scarcely studied in patients with Progressive Supranuclear Palsy (PSP) and Multiple System Atrophy (MSA).

OBJECTIVE

To evaluate the clinical correlates of FoF in PSP and MSA.

METHODS

A cross-sectional study with motor , cognitive and psychiatric assessment and longitudinal evaluation of falls and FoF at 6-month follow-up.

RESULTS

Twenty-one patients with PSP-P, 22 with MSA (13 MSA-P and 9 MSA-C) and 22 healthy controls were evaluated. 76.2% of patients with PSP and 86.4%of patients with MSA had FoF regardless of falls. Berg Balance Scale (p<0.001), Tinetti Mobility Test (p<0.01), Beck Anxiety Inventory (p=0.001) and Beck Depression Inventory-II (p=0.01) correlated with FoF in patients with PSP and MSA, whereas Timed up and Go test (p=0.01) and Starkstein's Apathy Scale only in MSA (p=0.04).

CONCLUSION

Mobility, balance and gait performance as well as anxiety and depression in PSP and MSA, and apathy in MSA were determinants of FoF. These findings underline the importance of a multidisciplinary approach to FoF in neurodegenerative atypical parkinsonism.

Heart rate variability and falls in Huntington's disease

PURPOSE

Persons with Huntington's disease (HD) have a high incidence of falls. Autonomic nervous system dysfunction has been reported even in early stages of this disease. To date, there has been no analysis of the relationship between heart rate variability (HRV) and falls in this patient population. The aim of the study reported here was to evaluate the relationship between HRV and falls in persons with HD.

METHODS

Huntington's disease patients enrolled in a prospective study on fear of falling and falls were assessed using short-term HRV analyses and blood pressure measures in both the resting and standing states. Time-frequency domains and nonlinear parameters were calculated. Data on falls, the risk of falling (RoF) and disease-specific scales were collected at baseline and at the end of the 6-month follow-up.

RESULTS

Of the 24 HD patients who were invited to participate in the study, 20 completed the baseline analysis and 18 completed the 6-month follow-up. At baseline, seven (35%) HD patients reported at least one fall (single fallers) and 13 (65%) reported ≥ 2 falls (recurrent fallers) in the previous 12 months. At baseline, recurrent fallers had lower RMSSD (root mean square of successive RR interval differences) in the resting state (RMSSD-resting), higher LF/HF (low/high frequency) ratio in both states and higher DFA-α1 parameter (detrended fluctuation analyses over the short term) in both states. This association was similar at the 6-month follow-up for recurrent fallers, who showed lower RMSSD-resting and higher LF/HF ratio in the standing state (LF/HF-standing) than single fallers. Significant correlations were found between the number of falls, RMSSD-resting and LF/HF-standing. No differences were found between recurrent and single fallers for any blood pressure measures.

CONCLUSIONS

The observed HRV pattern is consistent with a higher sympathetic prevalence associated with a higher RoF. Reduced parasympathetic HRV values in this patient population predict being a recurrent faller at 6 months of follow-up, independently of orthostatic phenomena.

Design and validation of a new instrument to assess fear of falling in Parkinson's disease

BACKGROUND

Fear of falling may be significantly associated with falls in Parkinson's disease (PD) and may have a negative impact on quality of life. Nevertheless, there are no valid and reliable tools to examine this condition in PD. The objective of this study was to design and determine the psychometric attributes of an instrument to assess fear of falling in PD.

METHODS

A prospective 1-year, 2-phase study was conducted to validate the Fear of Falling Scale, a self-assessed instrument for assessing fear of falling in PD. During phase 1, we designed a scale to measure the severity of fear of falling and determine its baseline psychometric characteristics, whereas phase 2 was a 1-year follow-up study to assess the frequency of falls and other clinical factors linked to fear of falling. Convergent and discriminant validity were assessed against the Fear of Falling Measure and the Starkstein Apathy Scale, respectively.

RESULTS

The Fear of Falling Scale showed high internal consistency, test-retest reliability, and strong convergent and discriminant validity. There was a significant association between fear of falling score and the presence of both generalized anxiety disorder and major depression, poor balance-related motor ability, increased nonmotor symptoms of PD, more severe impairments in activities of daily living, and increased motor fluctuations. Finally, generalized anxiety disorder was a significant predictor of number of falls during a 12-month follow-up period.

CONCLUSIONS

The Fear of Falling Scale is a valid and reliable instrument to assess fear of falling in PD. Fear of falling in PD is associated with specific psychiatric and motor disorders and is significantly related to the performance of balance-related motor functions. © 2019 International Parkinson and Movement Disorder Society.