Comorbidity of the nonmotor symptoms of Parkinson's disease

Physical exercise for people with Parkinson's disease: a systematic review and network meta-analysis

BACKGROUND

Physical exercise is effective in managing Parkinson's disease (PD), but the relative benefit of different exercise types remains unclear.

OBJECTIVES

To compare the effects of different types of physical exercise in adults with PD on the severity of motor signs, quality of life (QoL), and the occurrence of adverse events, and to generate a clinically meaningful treatment ranking using network meta-analyses (NMAs).

SEARCH METHODS

An experienced information specialist performed a systematic search for relevant articles in CENTRAL, MEDLINE, Embase, and five other databases to 17 May 2021. We also searched trial registries, conference proceedings, and reference lists of identified studies up to this date.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing one type of physical exercise for adults with PD to another type of exercise, a control group, or both.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. A third author was involved in case of disagreements. We categorized the interventions and analyzed their effects on the severity of motor signs, QoL, freezing of gait, and functional mobility and balance up to six weeks after the intervention using NMAs. Two review authors independently assessed the risk of bias using the risk of bias 2 (RoB 2) tool and rated the confidence in the evidence using the CINeMA approach for results on the severity of motor signs and QoL. We consulted a third review author to resolve any disagreements. Due to heterogeneous reporting of adverse events, we summarized safety data narratively and rated our confidence in the evidence using the GRADE approach.

MAIN RESULTS

We included 154 RCTs with a total of 7837 participants with mostly mild to moderate disease and no major cognitive impairment. The number of participants per study was small (mean 51, range from 10 to 474). The NMAs on the severity of motor signs and QoL included data from 60 (2721 participants), and 48 (3029 participants) trials, respectively. Eighty-five studies (5192 participants) provided safety data. Here, we present the main results. We observed evidence of beneficial effects for most types of physical exercise included in our review compared to a passive control group. The effects on the severity of motor signs and QoL are expressed as scores on the motor scale of the Unified Parkinson's Disease Rating Scale (UPDRS-M) and the Parkinson's Disease Questionnaire 39 (PDQ-39), respectively. For both scales, higher scores denote higher symptom burden. Therefore, negative estimates reflect improvement (minimum clinically important difference: -2.5 for UPDRS-M and -4.72 for PDQ-39). Severity of motor signs The evidence from the NMA (60 studies; 2721 participants) suggests that dance and gait/balance/functional training probably have a moderate beneficial effect on the severity of motor signs (dance: mean difference (MD) -10.18, 95% confidence interval (CI) -14.87 to -5.36; gait/balance/functional training: MD -7.50, 95% CI -11.39 to -3.48; moderate confidence), and multi-domain training probably has a small beneficial effect on the severity of motor signs (MD -5.90, 95% CI -9.11 to -2.68; moderate confidence). The evidence also suggests that endurance, aqua-based, strength/resistance, and mind-body training might have a small beneficial effect on the severity of motor signs (endurance training: MD -5.76, 95% CI -9.78 to -1.74; aqua-based training: MD -5.09, 95% CI -10.45 to 0.40; strength/resistance training: MD -4.96, 95% CI -9.51 to -0.40; mind-body training: MD -3.62, 95% CI -7.24 to 0.00; low confidence). The evidence is very uncertain about the effects of "Lee Silverman Voice training BIG" (LSVT BIG) and flexibility training on the severity of motor signs (LSVT BIG: MD -6.70, 95% CI -16.48 to 3.08; flexibility training: MD 4.20, 95% CI -1.61 to 9.92; very low confidence). Quality of life The evidence from the NMA (48 studies; 3029 participants) suggests that aqua-based training probably has a large beneficial effect on QoL (MD -15.15, 95% CI -23.43 to -6.87; moderate confidence). The evidence also suggests that mind-body, gait/balance/functional, and multi-domain training and dance might have a small beneficial effect on QoL (mind-body training: MD -7.22, 95% CI -13.57 to -0.70; gait/balance/functional training: MD -6.17, 95% CI -10.75 to -1.59; multi-domain training: MD -5.29, 95% CI -9.51 to -1.06; dance: MD -3.88, 95% CI -10.92 to 3.00; low confidence). The evidence is very uncertain about the effects of gaming, strength/resistance, endurance, and flexibility training on QoL (gaming: MD -8.99, 95% CI -23.43 to 5.46; strength/resistance training: MD -6.70, 95% CI -12.86 to -0.35; endurance training: MD -6.52, 95% CI -13.74 to 0.88; flexibility training: MD 1.94, 95% CI -10.40 to 14.27; very low confidence). Adverse events Only 85 studies (5192 participants) provided some kind of safety data, mostly only for the intervention groups. No adverse events (AEs) occurred in 40 studies and no serious AEs occurred in four studies. AEs occurred in 28 studies. The most frequently reported events were falls (18 studies) and pain (10 studies). The evidence is very uncertain about the effect of physical exercise on the risk of adverse events (very low confidence). Across outcomes, we observed little evidence of differences between exercise types.

AUTHORS' CONCLUSIONS

We found evidence of beneficial effects on the severity of motor signs and QoL for most types of physical exercise for people with PD included in this review, but little evidence of differences between these interventions. Thus, our review highlights the importance of physical exercise regarding our primary outcomes severity of motor signs and QoL, while the exact exercise type might be secondary. Notably, this conclusion is consistent with the possibility that specific motor symptoms may be treated most effectively by PD-specific programs. Although the evidence is very uncertain about the effect of exercise on the risk of adverse events, the interventions included in our review were described as relatively safe. Larger, well-conducted studies are needed to increase confidence in the evidence. Additional studies recruiting people with advanced disease severity and cognitive impairment might help extend the generalizability of our findings to a broader range of people with PD.

Evaluation of non-motor symptoms in cervical dystonia, hemifacial spasm, and blepharospasm patients and their correlation with motor symptoms

BACKGROUND

Awareness of non-motor symptoms has been increasing in recent years, but there are still few studies on this topic.

OBJECTIVE

Our aim was to evaluate various non-motor symptoms, especially psychiatric disorders, cognitive status, and sleep, in cervical dystonia (CD), hemifacial spasm (HFS), and blepharospasm (BPS) patients and to investigate whether these symptoms are related to the severity of motor symptoms.

METHODS

This was a single-center cross-sectional, observational, case-control study. Motor severity scales were used to determine disease severity. We evaluated non-motor symptoms with commonly used scales. A total of 73 patients and 73 control groups participated.

RESULTS

In CD patients, the MoCA total score, 'language', 'abstraction', and 'orientation' scores were statistically significantly lower; PSQI, ESS, and NMSQ scores were statistically significantly higher than controls. In the BPS group, the MoCA total score and the 'language' score were significantly lower, and the NMSQ score was statistically significantly higher than the controls. In the HFS group, MoCA total score, 'executive functions', 'language', and 'abstraction' scores were statistically significantly lower; PSQI scores are statistically significantly higher than controls. There was a positive correlation between the severity score and the PSQI score in the CD group and between the severity score and the NMSQ score in the BPS group. All three groups had significant cognitive impairments.

CONCLUSIONS

In CD, BPS, and HFS, non-motor symptoms are apparent with undeniable frequency in addition to common motor symptoms. Importantly, these NMS may cause significant deterioration in the quality of life of the patients.

Clinical and Non-Clinical Cardiovascular Disease Associated Pathologies in Parkinson's Disease

Despite considerable breakthroughs in Parkinson's disease (PD) research, understanding of non-motor symptoms (NMS) in PD remains limited. The lack of basic level models that can properly recapitulate PD NMS either in vivo or in vitro complicates matters. Even so, recent research advances have identified cardiovascular NMS as being underestimated in PD. Considering that a cardiovascular phenotype reflects sympathetic autonomic dysregulation, cardiovascular symptoms of PD can play a pivotal role in understanding the pathogenesis of PD. In this study, we have reviewed clinical and non-clinical published papers with four key parameters: cardiovascular disease risks, electrocardiograms (ECG), neurocardiac lesions in PD, and fundamental electrophysiological studies that can be linked to the heart. We have highlighted the points and limitations that the reviewed articles have in common. ECG and pathological reports suggested that PD patients may undergo alterations in neurocardiac regulation. The pathological evidence also suggested that the hearts of PD patients were involved in alpha-synucleinopathy. Finally, there is to date little research available that addresses the electrophysiology of in vitro Parkinson's disease models. For future reference, research that can integrate cardiac electrophysiology and pathological alterations is required.

Validation of the Non-Motor Symptoms Scale for Parkinson's Disease of Persian Version

Objective

We aimed to assess the validity and reliability of the Persian version of the NonMotor Symptoms Scale (NMSS) in Iranian patients with PD.

Methods

This cross-sectional study was conducted in patients with PD. After the cross-cultural adaptation of the NMSS, the acceptability, reliability, precision, and validity of the Persian NMSS were evaluated. For this purpose, in addition to NMSS, we used the following measures: Scales for Outcomes in Parkinson's Disease (SCOPA)-Autonomic (SCOPA-AUT), SCOPA-Sleep, Beck's Depression Inventory (BDI) questionnaire, Parkinson's Disease Questionnaire-8 questions (PDQ-8), SCOPA-Motor, SCOPA-Psychiatric Complications (SCOPA-PC), SCOPA-Cognition (SCOPA-COG), Mini-Mental State Examination (MMSE), Hoehn and Yahr Staging (H and Y), and Unified Parkinson Disease Rating Scale (UPDRS).

Results

186 patients were enrolled (mean age 64.46 ± 9.9 years; disease duration 5.59 ± 3.99 years; 118 (63.4%) male; mean NMSS score 52.01 ± 38.54). Neither the floor effect (2.7%) nor the ceiling effect (0.5%) was seen in NMSS total score. Cronbach's alpha of total NMSS was 0.84. The test-retest reliability was 0.93 for the NMSS total and 0.81-0.96 for domains. The standard error of measurement (SEM) was lower than half of the standard deviation for NMSS total and all domains. NMSS total showed a high correlation with UPDRS I (r_s = 0.84), UPDRS II (r_s = 0.58), PDQ-8 (r_s = 0.61), BDI (r_s = 0.71), SCOPA-sleep (r_s = 0.60), and SCOPA AUT (r_s = 0.66). NMSS has an acceptable discriminative validity based on disease duration and severity of disease according to H and Y staging.

Conclusion

The Persian NMSS is a valid and reliable measure for evaluating the burden of nonmotor symptoms in Iranian patients with PD.

Dimensions of apathy in Parkinson's disease

INTRODUCTION

Apathy is one of the most common neuropsychiatric manifestations in Parkinson's disease (PD). Recent proposals consider apathy as a multidimensional construct, which can manifest in behavioral, cognitive, emotional, and/or social dimensions. Apathy also overlaps conceptually and clinically with other non-motor comorbidities, particularly depression. Whether all of these dimensions are applicable to the apathetic syndrome experienced by people with PD is unclear. In the present study, we investigated the multidimensional pattern of apathy associated with PD, using the recently developed Apathy Motivation Index (AMI) which probes behavioral, emotional, and social apathy dimensions. We then examined the relationship between these dimensions and other features of PD commonly associated with apathy, including depression, anxiety, cognition, and motor state.

METHODS

A total of 211 participants were identified from the New Zealand Brain Research Institute (NZBRI) longitudinal PD cohort. One hundred eight patients and 45 controls completed the AMI, administered as an online questionnaire, and additional assessments including neuropsychiatric, neuropsychological, and motor scores. The pattern of dimensional apathy in PD was assessed using a repeated-measured analysis of variance, while simple linear regressions were performed to evaluate relationships between these dimensions and other variables.

RESULTS

We found a significant interaction between group (PD versus control) and apathy subscale, driven mainly by higher levels of social and behavioral-but not emotional-apathy in those with PD. This result was strikingly similar to a previous study investigating social apathy in PD. Distinct patterns of dimensional apathy were associated with depression and anxiety, with social and behavioral apathy positively associated with depression, and emotional apathy negatively associated with anxiety.

CONCLUSION

This work provides further evidence for a distinct pattern of apathy in people with PD in which deficits manifest in some-but not all-dimensions of motivated behavior. It emphasizes the importance of considering apathy as a multidimensional construct in clinical and research settings.

Fatigue in fluctuating Parkinson's disease patients: possible impact of safinamide

Fatigue is a common non-motor symptom in Parkinson's disease (PD). Among other pathophysiological mechanisms, neuroinflammation, a pathological PD hallmark associated with changes in glutamatergic transmission in basal ganglia, has been proposed as a crucial factor closely related to fatigue. To test the hypothesis that safinamide could represent an effective treatment of fatigue in PD patients, given its dual mechanism of action (it selectively and reversibly inhibits MAOB and modulates glutamate release), we administered the validated versions of fatigue severity scale (FSS) and Parkinson fatigue scale-16 (PFS-16) to 39 fluctuating PD patients with fatigue before and after a 24-week treatment period with safinamide as add-on therapy. An assessment of secondary variables such as depression, quality of life (QoL), and motor and non-motor symptoms (NMS) was conducted. After 24 weeks of treatment with safinamide, both FSS (p < 0.001) and PF-S16 (p = 0.02) scores were significantly lower than at baseline. Moreover, 46.2% and 41% of patients scored below the cut-off for the presence of fatigue according to FSS and PFS-16, respectively (responders). At follow-up, a significant difference emerged between responders and non-responders in mood, QoL, and NMS. Fatigue improved in fluctuating PD, and more than 40% of patients were "fatigue-free" after a 6 month treatment with safinamide. Patients without fatigue at follow-up displayed significantly better scores in QoL domains, such as mobility or activities of daily living, although disease severity remained stable, supporting the hypothesis that fatigue could considerably affect QoL. Drugs that interact with multiple neurotransmission systems, such as safinamide, could be useful in reducing this symptom.

Physical exercise for people with Parkinson's disease: a systematic review and network meta-analysis

BACKGROUND

Physical exercise is effective in managing Parkinson's disease (PD), but the relative benefit of different exercise types remains unclear.

OBJECTIVES

To compare the effects of different types of physical exercise in adults with PD on the severity of motor signs, quality of life (QoL), and the occurrence of adverse events, and to generate a clinically meaningful treatment ranking using network meta-analyses (NMAs).

SEARCH METHODS

An experienced information specialist performed a systematic search for relevant articles in CENTRAL, MEDLINE, Embase, and five other databases to 17 May 2021. We also searched trial registries, conference proceedings, and reference lists of identified studies up to this date.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing one type of physical exercise for adults with PD to another type of exercise, a control group, or both.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. A third author was involved in case of disagreements.  We categorized the interventions and analyzed their effects on the severity of motor signs, QoL, freezing of gait, and functional mobility and balance up to six weeks after the intervention using NMAs. Two review authors independently assessed the risk of bias using the risk of bias 2 (RoB 2) tool and rated the confidence in the evidence using the CINeMA approach for results on the severity of motor signs and QoL. We consulted a third review author to resolve any disagreements. Due to heterogeneous reporting of adverse events, we summarized safety data narratively and rated our confidence in the evidence using the GRADE approach.

MAIN RESULTS

We included 156 RCTs with a total of 7939 participants with mostly mild to moderate disease and no major cognitive impairment. The number of participants per study was small (mean 51, range from 10 to 474). The NMAs on the severity of motor signs and QoL included data from 71 (3196 participants), and 55 (3283 participants) trials, respectively. Eighty-five studies (5192 participants) provided safety data. Here, we present the main results. We observed evidence of beneficial effects for most types of physical exercise included in our review compared to a passive control group. The effects on the severity of motor signs and QoL are expressed as scores on the motor scale of the Unified Parkinson Disease Rating Scale (UPDRS-M) and the Parkinson's Disease Questionnaire 39 (PDQ-39), respectively. For both scales, higher scores denote higher symptom burden. Therefore, negative estimates reflect improvement (minimum clinically important difference: -2.5 for UPDRS-M and -4.72 for PDQ-39). Severity of motor signs The evidence from the NMA (71 studies; 3196 participants) suggests that dance has a moderate beneficial effect on the severity of motor signs (mean difference (MD) -10.32, 95% confidence interval (CI) -15.54 to -4.96; high confidence), and aqua-based, gait/balance/functional, and multi-domain training might have a moderate beneficial effect on the severity of motor signs (aqua-based: MD -7.77, 95% CI -13.27 to -2.28; gait/balance/functional: MD -7.37, 95% CI -11.39 to -3.35; multi-domain: MD -6.97, 95% CI -10.32 to -3.62; low confidence). The evidence also suggests that mind-body training and endurance training might have a small beneficial effect on the severity of motor signs (mind-body: MD -6.57, 95% CI -10.18 to -2.81; endurance: MD -6.43, 95% CI -10.72 to -2.28; low confidence). Flexibility training might have a trivial or no effect on the severity of motor signs (MD 2.01, 95% CI -4.82 to 8.98; low confidence). The evidence is very uncertain about the effects of strength/resistance training and "Lee Silverman Voice training BIG" (LSVT BIG) on the severity of motor signs (strength/resistance: MD -6.97, 95% CI -11.93 to -2.01; LSVT BIG: MD -5.49, 95% CI -14.74 to 3.62; very low confidence). Quality of life The evidence from the NMA (55 studies; 3283 participants) suggests that aqua-based training probably has a large beneficial effect on QoL (MD -14.98, 95% CI -23.26 to -6.52; moderate confidence). The evidence also suggests that endurance training might have a moderate beneficial effect, and that gait/balance/functional and multi-domain training might have a small beneficial effect on QoL (endurance: MD -9.16, 95% CI -15.68 to -2.82; gait/balance/functional: MD -5.64, 95% CI -10.04 to -1.23; multi-domain: MD -5.29, 95% CI -9.34 to -1.06; low confidence). The evidence is very uncertain about the effects of mind-body training, gaming, strength/resistance training, dance, LSVT BIG, and flexibility training on QoL (mind-body: MD -8.81, 95% CI -14.62 to -3.00; gaming: MD -7.05, 95% CI -18.50 to 4.41; strength/resistance: MD -6.34, 95% CI -12.33 to -0.35; dance: MD -4.05, 95% CI -11.28 to 3.00; LSVT BIG: MD 2.29, 95% CI -16.03 to 20.44; flexibility: MD 1.23, 95% CI -11.45 to 13.92; very low confidence). Adverse events Only 85 studies (5192 participants) provided some kind of safety data, mostly only for the intervention groups. No adverse events (AEs) occurred in 40 studies and no serious AEs occurred in four studies. AEs occurred in 28 studies. The most frequently reported events were falls (18 studies) and pain (10 studies). The evidence is very uncertain about the effect of physical exercise on the risk of adverse events (very low confidence). Across outcomes, we observed little evidence of differences between exercise types.

AUTHORS' CONCLUSIONS

We found evidence of beneficial effects on the severity of motor signs and QoL for most types of physical exercise for people with PD included in this review, but little evidence of differences between these interventions. Thus, our review highlights the importance of physical exercise regarding our primary outcomes severity of motor signs and QoL, while the exact exercise type might be secondary. Notably, this conclusion is consistent with the possibility that specific motor symptoms may be treated most effectively by PD-specific programs. Although the evidence is very uncertain about the effect of exercise on the risk of adverse events, the interventions included in our review were described as relatively safe. Larger, well-conducted studies are needed to increase confidence in the evidence. Additional studies recruiting people with advanced disease severity and cognitive impairment might help extend the generalizability of our findings to a broader range of people with PD.

Degenerative Spine Surgery in Patients with Parkinson Disease: A Systematic Review

BACKGROUND

Parkinson disease (PD) has been recognized as responsible for concurrent spinal disorders. Surgical correction may be necessary, but the complexity of such fragile patients may require specific considerations. We systematically reviewed the literature on degenerative spine surgery in patients with PD.

METHODS

PubMed, Scopus, Web of Science, and Cochrane were searched according to the PRISMA guidelines to include studies reporting clinical data of patients with PD undergoing degenerative spine surgery. Clinical characteristics, treatment protocols, and outcomes were analyzed.

RESULTS

We included 22 articles comprising 442 patients (61.5% female). Mean age was 66.9 ± 3.5 years (range, 41-83 years). Mean PD duration and modified Hoehn and Yahr stage were 4.46 ± 2.39 years and 2.3 ± 0.8, respectively. Operation types included fusion (55.3%) and decompression (41.6%). Mean operated spine levels were 6.0 ± 5.08. A total of 377 postoperative complications occurred in 34.6% patients, categorized into mechanical failure (58.0%), infection (15.1%), or neurologic (10.7%). Of patients, 31.8% required surgical revisions, with an average of 1.88 ± 1.03 revisions per patient. The average normalized presurgery, postsurgery, and final aggregate numeric patient outcome scores were 0.37 ± 0.13, 0.63 ± 0.18, and 0.61 ± 0.19, respectively, with a score of 0 and 1 representing the worst and best possible score.

CONCLUSIONS

Degenerative spine surgery in patients with PD is challenging, with complications and revisions occurring in up to a third of treated patients. Surgery should be offered when other treatment options have proved ineffective and is typically reserved for patients with myelopathy or significant disability. Successful outcomes depend on strong interdisciplinary support to control the movement disorder before and after surgery.

Palliative care in Parkinson disease and related disorders

Although neuropalliative care is a relatively new field, there is increasing evidence for its use among the degenerative parkinsonian syndromes, including idiopathic Parkinson disease, progressive supranuclear palsy, multiple system atrophy, dementia with Lewy bodies, and corticobasal syndrome. This chapter outlines the current state of evidence for palliative care among individuals with the degenerative parkinsonian syndromes with discussion surrounding: (1) disease burden and needs across the conditions; (2) utility, timing, and methods for advance care planning; (3) novel care models for the provision of palliative care; and 4) end-of-life care issues. We also discuss currently unmet needs and unanswered questions in the field, proposing priorities for research and the assessment of implemented care models.

Synucleinopathies

The α-synucleinopathies include pure autonomic failure, multiple system atrophy, dementia with Lewy bodies, and Parkinson disease. The past two decades have witnessed significant advances in the diagnostic strategies and symptomatic treatment of motor and nonmotor symptoms of the synucleinopathies. This chapter provides an in-depth review of the pathophysiology, pathology, genetic, epidemiology, and clinical and laboratory autonomic features that distinguish the different synucleinopathies with an emphasis on autonomic failure as a common feature. The treatment of the different synucleinopathies is discussed along with the proposal for multidisciplinary, individualized care models that optimally address the various symptoms. There is an urgent need for clinical scientific studies addressing patients at risk of developing synucleinopathies and the investigation of disease mechanisms, biomarkers, potential disease-modifying therapies, and further advancement of symptomatic treatments for motor and nonmotor symptoms.

Physical Exercise as a Potential Treatment for Fatigue in Parkinson's Disease? A Systematic Review and Meta-Analysis of Pharmacological and Non-Pharmacological Interventions

BACKGROUND

Fatigue is one of the most common and debilitating non-motor symptoms among patients with Parkinson's disease (PD) and significantly impacts quality of life. Therefore, effective treatment options are needed.

OBJECTIVE

To provide an update on randomized controlled trials (RCTs) including pharmacological and non-pharmacological (but non-surgical) treatments that examine the effects of fatigue on PD patients.

METHODS

We searched the MEDLINE, EMBASE, PsycINFO, CENTRAL, and CINAHL databases for (cross-over) RCTs on pharmacological and non-pharmacological interventions for treating fatigue in PD patients until May 2021. Meta-analyses for random-effects models were calculated when two or more studies on the same treatment option were available using standardized mean differences (SMDs) with 95% confidence intervals (CIs).

RESULTS

Fourteen pharmacological and 16 non-pharmacological intervention RCTs were identified. For pharmacological approaches, a meta-analysis could only be performed for modafinil compared to placebo (n = 2) revealing a non-significant effect on fatigue (SMD = - 0.21, 95% CI - 0.74-0.31, p = 0.43). Regarding non-pharmacological approaches, physical exercise (n = 8) following different training approaches versus passive or placebo control groups showed a small significant effect (SMD = - 0.37, 95% CI - 0.69- - 0.05, p = 0.02) which could not be demonstrated for acupuncture vs. sham-acupuncture (SMD = 0.16, 95% CI - 0.19-0.50, p = 0.37).

CONCLUSION

Physical exercise may be a promising strategy to treat fatigue in PD patients. Further research is required to examine the efficacy of this treatment strategy and further interventions. Future studies should differentiate treatment effects on physical and mental fatigue as the different underlying mechanisms of these symptoms may lead to different treatment responses. More effort is required to develop, evaluate, and implement holistic fatigue management strategies for PD patients.

Neurochemical, histological, and behavioral profiling of the acute, sub-acute, and chronic MPTP mouse model of Parkinson's disease

Parkinson's disease (PD) is a heterogeneous multi-systemic disorder unique to humans characterized by motor and non-motor symptoms. Preclinical experimental models of PD present limitations and inconsistent neurochemical, histological, and behavioral readouts. The 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD is the most common in vivo screening platform for novel drug therapies; nonetheless, behavioral endpoints yielded amongst laboratories are often discordant and inconclusive. In this study, we characterized neurochemically, histologically, and behaviorally three different MPTP mouse models of PD to identify translational traits reminiscent of PD symptomatology. MPTP was intraperitoneally (i.p.) administered in three different regimens: (i) acute-four injections of 20 mg/kg of MPTP every 2 h; (ii) sub-acute-one daily injection of 30 mg/kg of MPTP for 5 consecutive days; and (iii) chronic-one daily injection of 4 mg/kg of MPTP for 28 consecutive days. A series of behavioral tests were conducted to assess motor and non-motor behavioral changes including anxiety, endurance, gait, motor deficits, cognitive impairment, circadian rhythm and food consumption. Impairments in balance and gait were confirmed in the chronic and acute models, respectively, with the latter showing significant correlation with lesion size. The sub-acute model, by contrast, presented with generalized hyperactivity. Both, motor and non-motor changes were identified in the acute and sub-acute regime where habituation to a novel environment was significantly reduced. Moreover, we report increased water and food intake across all three models. Overall, the acute model displayed the most severe lesion size, while across the three models striatal dopamine content (DA) did not correlate with the behavioral performance. The present study demonstrates that detection of behavioral changes following MPTP exposure is challenging and does not correlate with the dopaminergic lesion extent.

Screening for non-motor symptoms in Egyptian patients with Parkinson’s disease

Background

Most of the patients with Parkinson’s disease (PD) suffer from non-motor symptoms (NMS). Despite their marked effect on patients’ quality of life, NMS remain under-estimated by physicians, patients and caregivers. The aim of this study was to suggest a battery to screen for the presence of NMS in PD patients in the setting of an outpatient clinic and to assess the NMS of PD in Egyptian patients and factors affecting them.

Results

This study was conducted on 50 patients with PD, 35 males (70%) and 15 females (30%) whom their age ranged from 36 to 80 years with a mean of 62.88 ± 8.74 years. All patients were assessed using the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), Apathy Scale (AS), Montreal Cognitive Assessment (MOCA), Hamilton Depression Rating Scale (HDRS) and Parkinson’s Disease Sleep Scale (PDSS). The mean age at disease onset was 59.10 ± 9.34 years and the mean disease duration was 3.76 ± 3.16 years. 98% of patients (49 out of 50) had at least one non-motor symptom. The mean MDS-UPDRS scores were 15.74 ± 7.93 for part I, 17.94 ± 11.61 for part II and 42.32 ± 22.74 for part III. The mean score for AS was 9.90 ± 10.66 with 70% of patients considered apathetic. The mean MOCA score was 21.12 ± 4.73 with 38 patients (76%) found to be cognitively impaired. The mean HDRS score was 12.26 ± 8.52 with 34 patients (68%) found to be depressed. The mean PDSS score was 92.22 ± 32.53 with sleep disturbances found in 38 patients (76%). A statistically significant negative correlation was found between the HDRS and PDSS scores (P value < 0.001). Age of patients, age at disease onset and disease duration were not correlated to MDS-UPDRS, AS, MOCA, HDRS and PDSS scores.

Conclusions

Most of the patients with PD were found to suffer from NMS including apathy, cognitive impairment, depression and sleep disturbances. Physicians need to screen their PD patients for NMS on regular basis using the appropriate tools. Self-administered questionnaires could function as reliable screening tools for NMS in PD patients.

Neurohormetic phytochemicals in the pathogenesis of neurodegenerative diseases

The world population is progressively ageing, assuming an enormous social and health challenge. As the world ages, neurodegenerative diseases are on the rise. Regarding the progressive nature of these diseases, none of the neurodegenerative diseases are curable at date, and the existing treatments can only help relieve the symptoms or slow the progression. Recently, hormesis has increased attention in the treatment of age-related neurodegenerative diseases. The concept of hormesis refers to a biphasic dose-response phenomenon, where low levels of the drug or stress exert protective of beneficial effects and high doses deleterious or toxic effects. Neurohormesis, as the adaptive aspect of hormetic dose responses in neurons, has been shown to slow the onset of neurodegenerative diseases and reduce the damages caused by aging, stroke, and traumatic brain injury. Hormesis was also observed to modulate anxiety, stress, pain, and the severity of seizure. Thus, neurohormesis can be considered as a potentially innovative approach in the treatment of neurodegenerative and other neurologic disorders. Herbal medicinal products and supplements are often considered health resources with many applications. The hormesis phenomenon in medicinal plants is valuable and several studies have shown that hormetic mechanisms of bioactive compounds can prevent or ameliorate the neurodegenerative pathogenesis in animal models of Alzheimer’s and Parkinson’s diseases. Moreover, the hormesis activity of phytochemicals has been evaluated in other neurological disorders such as Autism and Huntington’s disease. In this review, the neurohormetic dose–response concept and the possible underlying neuroprotection mechanisms are discussed. Different neurohormetic phytochemicals used for the better management of neurodegenerative diseases, the rationale for using them, and the key findings of their studies are also reviewed.

Brain microstructural alterations of depression in Parkinson's disease: A systematic review of diffusion tensor imaging studies

Depression, a leading cause of disability worldwide, is also the most prevalent psychiatric problem among Parkinson disease patients. Both depression and Parkinson disease are associated with microstructural anomalies in the brain. Diffusion tensor imaging techniques have been developed to characterize the abnormalities in cerebral tissue. We included 11 studies investigating brain microstructural abnormalities in depressed Parkinson's disease patients. The included studies found alterations to essential brain structural networks, including impaired network integrity for specific cortical regions, such as the temporal and frontal cortices. Additionally, findings indicate that microstructural changes in specific limbic structures, such as the prefronto-temporal regions and connecting white matter pathways, are altered in depressed Parkinson's disease compared to non-depressed Parkinson's disease and healthy controls. There remain inconsistencies between studies reporting DTI measures and depression severity in Parkinson disease participants. Additional research evaluating underlying neurobiological relationships between major depression, depressed Parkinson's disease, and non-depressed Parkinson's disease is required to disentangle further mechanisms that underlie depression and related somatic symptoms, in Parkinson disease.

The impact of cognitive impairment of individuals with Parkinson’s disease on their caregivers’ mental health: A systematic review protocol

Introduction

Parkinson’s disease is a motor disease, the second most common neurodegenerative disorder with cardinal symptoms including bradykinesia, rigidity, and rest tremor accompanied by cognitive difficulties. The caregivers play a crucial role for individuals with Parkinson’s disease; however, many of them may suffer from high caregiver burden and mental health deterioration. This protocol of a systematic review presents a methodology of the review about the impact of cognitive impairment of individuals with Parkinson’s disease on their caregivers’ mental health.

Material and methods

Research will be identified by combining electronic databases searching and hand searching. The following databases will be included: Medline, PsycInfo, Web of Sciences, Cochrane, CINAHL, Embase and Scopus. The inclusion and exclusion criteria followed to PECOS model. The population of informal caregivers is defined as family members providing care on a patient with Parkinson’s disease. Exposure is linked with the evaluation of a cognitive functioning and outcome is defined as mental health among caregivers of individuals with Parkinson’s disease. We will include two types of studies: observational and intervention. Both, screening and eligibility will be done by two independent reviewers. Study quality will be assessed by two authors independently. Data will be extracted by two reviewers independently and will follow a pre-pilot extraction form. Any discrepancies will be resolved by discussion or/and consultation with another reviewer. The synthesis without meta-analysis (SWiM) guidelines will be used to report on included studies data. The metanalysis with usage the statistical software R version 4.1.2 (2021-11-01) “Bird Hippie” and R metaphor package 3.0–2 of will be conducted if possible.

Discussion

The goal of this systematic review is to present the association between caregivers’ mental health problems and their proteges’ cognitive impairment. It will enable to identify the gaps in literature and its methodology giving the suggestions for further research.

Protocol registration

Protocol registration number in PROSPERO: CRD42022296670

Dual task effect on upper and lower extremity skills in different stages of Parkinson's disease

BACKGROUND AND PURPOSE

Loss of automaticity and deteriorated executive function give rise to dual task deficits in Parkinson's disease (PD). This study aimed to compare single task and dual task upper and lower extremity skills in people with PD (PwPD) at different stages of PD and to examine the dual task effect (DTE) on upper and lower extremity skills in PwPD at different stages of PD. The second aim was to investigate the relationship between the DTE and the quality of life in PwPD.

METHODS

30 patients divided into 2 groups as mild PD group and moderate PD group according to the Modified Hoehn & Yahr Scale. 15 age matched healthy adults were recruited as the control group. The Unified Parkinson's Disease Rating Scale (UPDRS), the Purdue Pegboard Test (PPT), the Timed Up and Go Test (TUG), the 10 Meter Walk Test (10MWT), and the Parkinson's Disease Questionnaire (PDQ-8) were used for assessments.

RESULTS

Single task and dual task scores of all assessments of all groups were significantly different. The DTE on PPT was greater in mild and moderate PD groups than control group and significantly lower in mild PD group than moderate PD group. However, DTE on the TUG and 10MWT was not different in mild PD group than control group and DTE significantly lower in both groups than moderate PD group. Significant correlations between the DTE on PPT, TUG and 10MWT and the PDQ-8 in PwPD were observed.

CONCLUSION

Dual task has a worsening effect on upper and lower extremity skills in PwPD. This effect can be observed earlier in upper extremity skills than lower extremity skills. Also, the DTE and the QoL in PwPD are related.

Predictors of the change in burden, strain, mood, and quality of life among caregivers of Parkinson's disease patients

BACKGROUND AND OBJECTIVE

Caregiver burden in Parkinson's disease (PD) has been studied in many cross-sectional studies but poorly in longitudinal ones. The aim of the present study was to analyze the change in burden, strain, mood, and quality of life (QoL) after a 2-year follow-up in a cohort of caregivers of patients with PD and also to identify predictors of these changes.

PATIENTS AND METHODS

PD patients and their caregivers who were recruited from January/2016 to November/2017 from 35 centers of Spain from the COPPADIS cohort were included in the study. They were evaluated again at 2-year follow-up. Caregivers completed the Zarit Caregiver Burden Inventory (ZCBI), Caregiver Strain Index (CSI), Beck Depression Inventory-II (BDI-II), and EUROHIS-QOL 8-item index (EUROHIS-QOL8) at baseline (V0) and at 2-year follow-up (V2). General linear model repeated measure and lineal regression models were applied.

RESULTS

Significant changes, indicating an impairment, were detected on the total score of the ZCBI (p < 0.0001), CSI (p < 0.0001), BDI-II (p = 0.024), and EUROHIS-QOL8 (p = 0.002) in 192 PD caregivers (58.82 ± 11.71 years old; 69.3% were females). Mood impairment (BDI-II; β = 0.652; p < 0.0001) in patients from V0 to V2 was the strongest factor associated with caregiver's mood impairment after the 2-year follow-up. Caregiver's mood impairment was the strongest factor associated with an increase from V0 to V2 on the total score of the ZCBI (β = 0.416; p < 0.0001), CSI (β = 0.277; p = 0.001), and EUROHIS-QOL (β = 0.397; p = 0.002).

CONCLUSION

Burden, strain, mood, and QoL were impaired in caregivers of PD patients after a 2-year follow-up. Mood changes in both the patient and the caregiver are key aspects related to caregiver burden increase.

Idiopathic Parkinson's disease and chronic pain in the era of deep brain stimulation: a systematic review and meta-analysis

OBJECTIVE

Pain is the most common nonmotor symptom of Parkinson's disease (PD) and is often undertreated. Deep brain stimulation (DBS) effectively mitigates the motor symptoms of this multisystem neurodegenerative disease; however, its therapeutic effect on nonmotor symptoms, especially pain, remains inconclusive. While there is a critical need to help this large PD patient population, guidelines for managing this significant disease burden are absent. Herein, the authors systematically reviewed the literature and conducted a meta-analysis to study the influence of traditional (subthalamic nucleus [STN] and globus pallidus internus [GPi]) DBS on chronic pain in patients with PD.

METHODS

The authors performed a systematic review of the literature and a meta-analysis following PRISMA guidelines. Risk of bias was assessed using the levels of evidence established by the Oxford Centre for Evidence-Based Medicine. Inclusion criteria were articles written in English, published in a peer-reviewed scholarly journal, and about studies conducting an intervention for PD-related pain in no fewer than 5 subjects.

RESULTS

Twenty-six studies were identified and included in this meta-analysis. Significant interstudy heterogeneity was detected (Cochran's Q test p < 0.05), supporting the use of the random-effects model. The random-effects model estimated the effect size of DBS for the treatment of idiopathic pain as 1.31 (95% CI 0.84-1.79). The DBS-on intervention improved pain scores by 40% as compared to the control state (preoperative baseline or DBS off).

CONCLUSIONS

The results indicated that traditional STN and GPi DBS can have a favorable impact on pain control and improve pain scores by 40% from baseline in PD patients experiencing chronic pain. Further trials are needed to identify the subtype of PD patients whose pain benefits from DBS and to identify the mechanisms by which DBS improves pain in PD patients.

Fatigue in Brazilian patients with Parkinson's disease

Fatigue is a non-motor symptom of high prevalence in Parkinson’s disease (PD); however, it is still unknown and neglected by health professionals.

Drug prescriptions and dementia incidence: a medication-wide association study of 17000 dementia cases among half a million participants

BACKGROUND

Previous studies have suggested that some medications may influence dementia risk. We conducted a hypothesis-generating medication-wide association study to investigate systematically the association between all prescription medications and incident dementia.

METHODS

We used a population-based cohort within the Secure Anonymised Information Linkage (SAIL) databank, comprising routinely-collected primary care, hospital admissions and mortality data from Wales, UK. We included all participants born after 1910 and registered with a SAIL general practice at ≤60 years old. Follow-up was from each participant's 60th birthday to the earliest of dementia diagnosis, deregistration from a SAIL general practice, death or the end of 2018. We considered participants exposed to a medication if they received ≥1 prescription for any of 744 medications before or during follow-up. We adjusted for sex, smoking and socioeconomic status. The outcome was any all-cause dementia code in primary care, hospital or mortality data during follow-up. We used Cox regression to calculate hazard ratios and Bonferroni-corrected p values.

RESULTS

Of 551 344 participants, 16 998 (3%) developed dementia (median follow-up was 17 years for people who developed dementia, 10 years for those without dementia). Of 744 medications, 221 (30%) were associated with dementia. Of these, 217 (98%) were associated with increased dementia incidence, many clustering around certain indications. Four medications (all vaccines) were associated with a lower dementia incidence.

CONCLUSIONS

Almost a third of medications were associated with dementia. The clustering of many drugs around certain indications may provide insights into early manifestations of dementia. We encourage further investigation of hypotheses generated by these results.

Embelin and levodopa combination therapy for improved Parkinson's disease treatment

Parkinson’s disease (PD), a progressive neurodegenerative disorder, affects dopaminergic neurons. Oxidative stress and gut damage play critical roles in PD pathogenesis. Inhibition of oxidative stress and gut damage can prevent neuronal death and delay PD progression. The objective of this study was to evaluate the therapeutic effect of embelin or the combination with levodopa (LD) in a rotenone-induced PD mouse model. At the end of experimentation, the mice were sacrificed and the midbrain was used to evaluate various biochemical parameters, such as nitric oxide, peroxynitrite, urea, and lipid peroxidation. In the substantia nigra (midbrain), tyrosine hydroxylase (TH) expression was examined by immunohistochemistry, and Nurr1 expression was evaluated by western blotting. Gut histopathology was evaluated on tissue sections stained with hematoxylin and eosin. In silico molecular docking studies of embelin and α-synuclein (α-syn) fibrils were also performed. Embelin alone or in combination with LD ameliorated oxidative stress and gut damage. TH and Nurr1 protein levels were also significantly restored. Docking studies confirmed the affinity of embelin toward α-syn. Taken together, embelin could be a promising drug for the treatment of PD, especially when combined with LD.

The association between restless leg syndrome and anxiety in Parkinson's disease: a case-control study

OBJECTIVE

To shed light on the association between restless leg syndrome (RLS) and anxiety in Parkinson's disease (PD) population.

METHODS

This was a case-control study including 129 PD participants with and without anxiety who presented to the Aerospace Center Hospital in Beijing, China. Anxiety was evaluated by using the Beck Anxiety Index score. RLS was assessed using the minimal diagnostic criteria of the International Restless Legs Study Group and RLS symptom frequency and treatment. We then examined the relationship between RLS and anxiety by logistic regression models and subgroup as well as interaction analyses.

RESULTS

The proportion of RLS in PD with anxiety was significantly higher in the PD without anxiety (p < 0.001). The multivariate logistic regression models indicated that PD participants with RLS had a 5.98-fold higher risk of anxiety in PD than those without RLS (OR, 6.98; 95% CI, 2.77-17.59). Subgroup analyses indicated that PD with RLS tended to be associated with a greater risk of anxiety in all stratified subgroups (adjusted ORs >1). Furthermore, the interaction analyses revealed no interactive role in the association between RLS and anxiety.

CONCLUSIONS

The present case-control study suggests that RLS is an independent risk factor for anxiety in PD patients. Early attention and targeted treatment for RLS may be necessary for mood management in PD. Larger prospective cohort studies are wanted to validate these findings.

Perceived Health, Psychological Distress, and Subjective Well-Being among Older Adults with Parkinson's Disease: A Cross-Lagged Analysis

A growing aging population leads to a gradual increase in the number of patients with Parkinson's disease (PD). This study examines how perceived health, psychological distress, and subjective well-being evolve in older adults with PD. A cross-lagged study design was employed using data from Waves 4 and 6 of the Survey of Health, Aging and Retirement in Europe (SHARE). In total, 421 older adults diagnosed with PD at baseline (46% women; mean age 74.98  ±  9.05 years) were included in the study and were followed up after a four-year lag. Auto-regressive and cross-lagged associations between the measured variables were examined in reciprocal models. Individual differences in perceived health, psychological distress, and subjective well-being were relatively stable over the 4-year lag. A final reciprocal model with significant cross-lagged effects explained the underlying structure of the sample data well: χ2 (49) = 101.876, p < 0.001, CFI =  0.953, NFI = 0.935, RMSEA =  0.050, and AIC = 241.876. Increased difficulties in fulfilling instrumental activities and a lowered level of subjective well-being were particularly noticeable in older adults with PD during the four-year follow-up. Additional attention should be paid to helping older patients with PD cope better with their functional limitations and improve their sense of well-being.

Impaired dopamine metabolism is linked to fatigability in mice and fatigue in Parkinson's disease patients

Fatigue is a common symptom of Parkinson’s disease that compromises significantly the patients’ quality of life. Despite that, fatigue has been under-recognized as symptom, its pathophysiology remains poorly understood, and there is no adequate treatment so far. Parkinson’s disease is characterized by the progressive loss of midbrain dopaminergic neurons, eliciting the classical motor symptoms including slowing of movements, muscular rigidity and resting tremor. The dopamine synthesis is mediated by the rate-limiting enzyme tyrosine hydroxylase, which requires tetrahydrobiopterin as a mandatory cofactor. Here, we showed that reserpine administration (1 mg/kg, two intraperitoneal injections with an interval of 48 h) in adult Swiss male mice (8–10 weeks; 35–45 g) provoked striatal depletion of dopamine and tetrahydrobiopterin, and intolerance to exercise. The poor exercise performance of reserpinized mice was not influenced by emotional or anhedonic factors, mechanical nociceptive thresholds, electrocardiogram pattern alterations or muscle-impaired bioenergetics. The administration of levodopa (100 mg/kg; i.p.) plus benserazide (50 mg/kg; i.p.) rescued reserpine-induced fatigability-like symptoms and restored striatal dopamine and tetrahydrobiopterin levels. Remarkably, it was observed, for the first time, that impaired blood dopamine metabolism inversely and idependently correlated with fatigue scores in eighteen idiopathic Parkinson’s disease patients (male n = 13; female n = 5; age 61.3 ± 9.59 years). Altogether, this study provides new experimental and clinical evidence that fatigue symptoms might be caused by the impaired striatal dopaminergic neurotransmission, pointing to a central origin of fatigue in Parkinson’s disease.

Characterization of nonmotor behavioral impairments and their neurochemical mechanisms in the MitoPark mouse model of progressive neurodegeneration in Parkinson's disease

Mitochondrial dysfunction has been implicated as a key player in the pathogenesis of Parkinson's disease (PD). The MitoPark mouse, a transgenic mitochondrial impairment model developed by specific inactivation of TFAM in dopaminergic neurons, spontaneously exhibits progressive motor deficits and neurodegeneration, recapitulating several features of PD. Since nonmotor symptoms are now recognized as important features of the prodromal stage of PD, we comprehensively assessed the clinically relevant motor and nonmotor deficiencies from ages 8-24 wk in both male and female MitoPark mice and their littermate controls. As expected, motor deficits in MitoPark mice began around 12-14 wk and became severe by 16-24 wk. Interestingly, MitoPark mice exhibited olfactory deficits in the novel and social scent tests as early as 10-12 wk as compared to age-matched littermate controls. Additionally, male MitoPark mice showed spatial memory deficits before female mice, beginning at 8 wk and becoming most severe at 16 wk, as determined by the Morris water maze. MitoPark mice between 16 and 24 wk spent more time immobile in forced swim and tail suspension tests, and made fewer entries into open arms of the elevated plus maze, indicating a depressive and anxiety-like phenotype, respectively. Importantly, depressive behavior as determined by immobility in forced swim test was reversible by antidepressant treatment with desipramine. Neurochemical and mechanistic studies revealed significant changes in CREB phosphorylation, BDNF, and catecholamine levels as well as neurogenesis in key brain regions. Collectively, our results indicate that MitoPark mice progressively exhibit deficits in olfactory discrimination, cognitive learning and memory, and anxiety- and depression-like behaviors as well as key neurochemical signaling associated with nonmotor deficits in PD. Thus, MitoPark mice can serve as an invaluable model for studying nonmotor deficits in addition to studying the motor deficits related to pathology in PD.

Reasons for hospitalization and factors of mortality in patients with Parkinson's disease in the Philippines

Aim: We aimed to determine the reasons for hospitalizations and factors of mortality of Filipino Parkinson's disease (PD) patients in a tertiary hospital. Methods: We conducted a retrospective review of medical records of PD patients admitted to our institution between 2016 and 2018. Demographic and clinical data were analyzed. Results: We included 166 PD patients. The most common cause of admission was infectious (pneumonia, urinary tract, and skin-soft tissue infections) (n = 65, 39.2%). The most common cause of mortality was sepsis (n = 9, 5.4%). Renal comorbidity was a significant factor of mortality (OR: 3.67, 95% CI: 1.11-12.12; p = 0.033). Conclusion: Interventions designed to reduce the risk of complications in PD patients should be prioritized to potentially decrease the probability of eventual hospitalization.

A Comprehensive Phenotype of Non-motor Impairments and Distribution of Alpha-Synuclein Deposition in Parkinsonism-Induced Mice by a Combination Injection of MPTP and Probenecid

Parkinson's disease (PD) is characterized by non-motor symptoms as well as motor deficits. The non-motor symptoms rarely appear individually and occur simultaneously with motor deficits or independently. However, a comprehensive research on the non-motor symptoms using an experimental model of PD remains poorly understood. The aim of the current study is to establish a chronic mouse model of PD mimicking the comprehensive non-motor symptoms of human PD by injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and probenecid (MPTP/p). The non-motor and motor symptoms were evaluated by performing buried food, short-term olfactory memory, hot plate, open field, tail suspension, Y maze, novel object recognition, bead expulsion, one-h stool collection, rotarod, rearing, catalepsy, and akinesia tests after 10 injections of MPTP/p into mice. The expression levels of α-synuclein, glial fibrillary acidic protein (GFAP), tyrosine hydroxylase (TH) or DJ-1 were analyzed by Western blotting or immunostaining. MPTP/p-treated mice achieved to reproduce the key features of non-motor symptoms including olfactory deficit, thermal hyperalgesia, anxiety, depression, cognitive decline, and gastrointestinal dysfunction in addition to motor deficits. The MPTP/p-treated mice also showed the high levels of α-synuclein and low levels of TH and DJ-1 in striatum, substantia nigra, olfactory bulb, hippocampus, amygdala, prefrontal cortex, locus coeruleus, or colon. In addition, the expression levels of phosphorylated-α-synuclein and GFAP were elevated in the striatum and substantia nigra in the MPTP/p-treated mice. Taken together, our study clarifies that the chronic MPTP/p-treated mice have a variety of non-motor dysfunctions as well as motor abnormalities by α-synuclein overexpression and dopaminergic depletion. Therefore, the study of comprehensive phenotypes of non-motor symptoms in one PD model would advance in-depth understandings of neuropathological alternations and contribute to future strategies for PD treatment.

Therapeutic Strategies to Treat or Prevent Off Episodes in Adults with Parkinson's Disease

Parkinson's disease is a chronic, neurodegenerative disease, which manifests with a mixture of motor, cognitive and behavioural symptoms. Levodopa is the most effective antiparkinsonian treatment to date, although chronic use engenders a mixture of complications in a substantial proportion of patients. Amongst these is the occurrence of episodes of worsening symptoms-'off' phenomena. These episodes can manifest with either motor or non-motor symptoms or a combination of these features and have been found to have profound impacts on patients' quality of life. Although preventative measures are poorly evidenced, avoiding excessive total daily levodopa intake in selected populations that are deemed to be of a higher risk for developing these episodes warrants further exploration. Methods to improve levodopa bioavailability and delivery to the brain are currently available and are of value in addressing these episodes once they have become established. These include modifications to levodopa formulations as well as the use of complimentary agents that improve levodopa bioavailability. The deployment of device-assisted approaches is a further dimension that can be considered in addressing these debilitating episodes. This review summarises the clinical manifestations of 'off' phenomena and the current approaches to treat them. Although we briefly discuss clinical advances on the horizon, the predominant focus is on existing, established treatments.

Impact of Obstructive Sleep Apnea on Cognitive and Motor Functions in Parkinson's Disease

INTRODUCTION

Parkinson's disease (PD) is a chronic neurodegenerative disorder that presents with motor and non-motor manifestations. Amongst the non-motor features, various forms of sleep disturbances can occur, and obstructive sleep apnea (OSA) is considered to be a common comorbidity. We conducted this systematic review and meta-analysis to assess the impact of OSA on cognitive and motor functions in PD.

METHODS

The information sources of for this systematic review and meta-analysis were PubMed, SCOPUS, Web of Science, and ScienceDirect. Studies meeting the following criteria were included: (1) studies including idiopathic PD patients, (2) studies using polysomnography to categorize PD patients into PD with OSA and PD without OSA, and (3) studies with observational designs (case-control, cohort, or cross-sectional). Data analysis was performed using RevMan.

RESULTS

Our meta-analysis showed that OSA was associated with significantly lower scores of Montreal Cognitive Assessments (MoCA) (mean difference (MD) = -0.70, 95% confidence interval (CI) [-1.28, -0.13], P = 0.01) and Mini-Mental State Examination (MMSE) (MD = -0.69, 95% CI [-1.17, -0.21], P = 0.005). Moreover, the score of the motor part of the Unified Parkinson's Disease Rating Scale (UPDRS III) was significantly higher in PD patients with OSA as compared with those without OSA (MD = 1.63, 95% CI [0.03, 3.23], P = 0.049).

CONCLUSIONS

OSA is associated with increased severity of PD-associated cognitive dysfunction and motor symptoms. However, further studies are needed to corroborate these findings, assess the underlying mechanisms by which OSA influences the motor and cognitive functions in PD, and investigate whether OSA can accelerate the neurodegenerative process of PD. © 2020 International Parkinson and Movement Disorder Society.

Synucleinopathies

PURPOSE OF REVIEW

This article reviews the α-synucleinopathies pure autonomic failure, multiple system atrophy, dementia with Lewy bodies, and Parkinson disease with respect to autonomic failure.

RECENT FINDINGS

The pattern and severity of autonomic involvement in the synucleinopathies is related to differences in cellular deposition and neuronal populations affected by α-synuclein aggregation, which influences the degree and manifestation of autonomic failure. Clinical and laboratory autonomic features distinguish the different synucleinopathies based on pattern and severity. These features also determine which patients are at risk for evolution from pure autonomic failure to the synucleinopathies with prominent motor involvement, such as multiple system atrophy, dementia with Lewy bodies, or Parkinson disease.

SUMMARY

Autonomic failure is a key feature of the synucleinopathies, with varying type and degree of dysfunction from predominantly peripheral involvement in the Lewy body disorders to central involvement in multiple system atrophy.

Optical coherence tomography measurements as potential imaging biomarkers for Parkinson's disease: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Retinal pathological changes may precede or accompany the deterioration of brain tissue in Parkinson's disease (PD). The purpose of this meta-analysis was to assess the usefulness of optical coherence tomography (OCT) measurements as potential imaging biomarkers for PD.

METHODS

PubMed, Embase, Web of Science and Cochrane Library databases were systematically searched for observational studies (published prior to 30 May 2020) comparing the OCT measurements between PD patients and healthy controls (HCs). Our main end-points were peripapillary retinal nerve fiber layer (pRNFL) thickness, macular ganglion cell complex thickness, macular thickness and macular volume. Pooled data were assessed by use of a random-effects model.

RESULTS

A total of 36 observational studies were identified that included 1712 patients with PD (2548 eyes) and 1778 HCs (2646 eyes). Compared with the HC group, the PD group showed a significant reduction in mean pRNFL thickness (weighted mean difference [WMD] -3.51 μm, 95% confidence interval [CI] -4.84, -2.18; p = 0.000), all quadrants at the pRNFL (WMD range -7.65 to -2.44 μm, all p < 0.05), macular fovea thickness (WMD -5.62 μm, 95% CI -7.37, -3.87; p = 0.000), all outer sector thicknesses at the macula (WMD range -4.68 to -4.10 μm, all p < 0.05), macular volume (WMD -0.21 mm³ , 95% CI -0.36, -0.06; p < 0.05) and macular ganglion cell complex thickness (WMD -4.18 μm, 95% CI -6.07, -2.29; p < 0.05).

CONCLUSIONS

Our pooled data confirmed robust associations between retinal OCT measurements and PD, highlighting the usefulness of OCT measurements as potential imaging biomarkers for PD.

Investigation of non-motor symptoms, balance, muscle strength, and functional mobility in patients with parkinson's disease

PURPOSE

Although both motor symptoms and non-motor symptoms (NMSs) occur in patients with Parkinson's disease (PD), clinical practice focuses more on motor symptoms. The aim of this study was to examine balance, muscle strength, and mobility in relation with NMSs in patients with PD. The other aim of this study was to investigate the relationship between NMSs and muscle strength, balance, and functional mobility in PD.

MATERIALS AND METHODS

The study included 24 patients with PD (between Hoehn & Yahr Stage 1 and 3) and 20 healthy individuals of similar age and sex. The participants' balance was assessed with the Biodex Balance System (Biodex Medical Systems, Shirley, NY, USA), muscle strength assessments were conducted with a Biodex^® System 4 Dynamometer device, and functional mobility was assessed with the Timed Up and Go test (TUG). The non-motor symptoms scale was used for NMSs.

RESULTS

We found that lower extremity strength scores were lower and NMSs, balance, and mobility scores were greater in patients with PD in comparison to healthy controls (p < 0.05). The correlation analysis revealed that higher NMSs were related to reduced knee extension strength and cognitive dual task performance.

CONCLUSION

Although no relationship between NMSs and balance was observed, the relationship between the TUG + cognitive task and muscle strength suggests that NMSs should be carefully evaluated along with the motor symptoms, which deteriorate beginning with the early period.

Progression of fatigue in Parkinson's disease - a 9-year follow-up

BACKGROUND AND PURPOSE

Although highly disabling, the pathogenesis and evolution of fatigue in Parkinson's disease (PD) is largely unknown, and no sufficiently documented treatment currently exists. The aim of the present study was to investigate the evolution of fatigue during the first 9 years after diagnosis.

METHODS

This study is part of the Norwegian ParkWest collaboration, a prospective population-based longitudinal cohort study. The present study comprised 191 newly diagnosed patients and 170 control participants. Fatigue was assessed by the Fatigue Severity Scale, with examinations at baseline and then every other year up to 9 years of follow-up. Linear mixed models were applied to investigate possible variables associated with fatigue.

RESULTS

It was found that there was a statistically significant increase in the proportion of PD patients with fatigue during the first 9 years after diagnosis. A large proportion of patients had a significant increase or decrease in fatigue score between consecutive visits. In addition, the relative risk of persistent fatigue and ever having fatigue was higher than for controls. There were statistically significant longitudinal associations between higher levels of fatigue and female gender, comorbidity at baseline, depressive symptoms, dependency in activities of daily living and better cognitive functioning. Lower levels of fatigue were associated with the use of dopamine agonists.

CONCLUSION

Fatigue is a common, severely limiting symptom in PD. This study demonstrates associations with other factors that could yield a better understanding of the symptom and thus possible treatment strategies, although further investigations are necessary to establish causal relationships.

Autonomic Dysfunction in the Synucleinopathies

Autonomic dysfunction is a characteristic feature in the synucleinopathies. Differences in cellular deposition and neuronal populations affected by α-synuclein aggregation influence the manifestations and severity of autonomic failure in the different synucleinopathy disorders. The Lewy body disorders (Parkinson's disease, dementia with Lewy bodies, and pure autonomic failure) have predominantly peripheral involvement, whereas multiple system atrophy chiefly manifests as central autonomic failure. Clinical and laboratory features may be useful in distinguishing the different synucleinopathies based on the pattern and severity of autonomic failure. Treatment recommendations are aimed at the underlying pathophysiology and utilize non-pharmacologic and pharmacologic approaches. This review will focus on pathophysiology, clinical manifestations, and management recommendations for autonomic failure including neurogenic orthostatic hypotension, thermoregulatory dysfunction, genitourinary dysfunction, and gastrointestinal dysfunction in the synucleinopathies.

Global cortical atrophy may be associated with fatigue in patients with parkinson's disease

PURPOSE

Fatigue has been recognized as a common non-motor problem in patients with Parkinson's disease (PD). The determination of the clinical correlates of fatigue in PD patients is necessary. The purpose of this study was to explore the risk factors related to the severity of fatigue in PD.

PATIENTS AND METHODS

In this study, 141 patients with PD were recruited. All patients were evaluated comprehensively, including motor function, fatigue severity scale (FSS), cognition and psychiatric status. Brain magnetic resonance imaging (MRI) examinations were performed to assess the severity of white matter hyperintensities, and the presence of silent lacunes, medial temporal lobe atrophy (MTLA), and global cortical atrophy (GCA). The crude associations of variables with FSS were examined using Pearson (nor-mally distributed) or Spearman correlation (categorical or non-normal distributed) analyses. Multiple linear regression analysis was performed to find the correlates of fatigue severity in PD patients.

RESULTS

In the whole sample, with FSS as the dependent variable in a linear regression model, Hamilton Depression Rating Scale (HAM-D), GCA, female sex were significant correlates of FSS, accounting for 24% of the variance of it. When subjects with depression (HAM-D ≥ 35) were excluded, HAM-D, GCA, female sex remained significant correlates of FSS, accounting for 22% of the variance of FSS. There is no correlation between white matter hyperintensities and FSS.

CONCLUSION

GCA may be an important correlate of the fatigue severity commonly observed in PD patients.

Screening for depression in movement disorders clinic

BACKGROUND

Depression is the most common, though often under-recognised, neuropsychiatric disturbance in movement disorders (MD).

OBJECTIVE

This study aimed to establish whether a briefer screening measure such as a visual analogue screening measure (Emotions Thermometer) or Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) could be a potentially suitable screening tool for depression in MD patients.

METHOD

Patients attending a regional MD outpatient clinic completed the Emotional Thermometer 7-item tool (ET7), the Hospital Anxiety and Depression Scale (HADS) and the Neurological Disorders Depression Inventory for Epilepsy (NDDIE). We used the Major Depression Inventory which provided the diagnosis of depression based on ICD-10 and DSM-IV as our diagnostic gold standard to compare the performance of ET7 and its individual sub-scales, its briefer version ET4, HADS, and NDDIE. Sensitivity, specificity, positive predictive value, negative predictive value and receiver operating characteristic curves were calculated to compare the performance of the screening tools.

RESULTS

In total, 188 patients were included in the analysis. The most accurate tools as determined by Receiver Operating Characteristics curve were HADS-D for ICD-10 depressive episode and DepT for DSM-IV major depression. ET4 performed well as a 'rule-out' screening tool for both DSM-IV and ICD-10 depression. ET4 performance was comparable to HADS without the need for clinician scoring. The briefer ET4 performed almost as well as ET7.

CONCLUSION

Emotions Thermometer and NDDI-E are quick and reliable screening tools for depression in the MD population and are comparable to HADS. We suggest routine use of visual analogue ET4 as it is briefer, requires less time to complete and does not require scoring from the clinicians. It has the potential to be widely implemented across busy neurology clinics to assist in depression screening.

Non-motor symptoms depending on motor severity in Japanese patients with Parkinson's disease: A multicenter cross-sectional study

BACKGROUND

Although non-motor symptoms (NMS) in patients with Parkinson's disease (PD) often worsen as the severity of motor symptoms (MS) increases, few studies have assessed the associated factors of non-motor symptoms.

OBJECTIVE

This study aims to determine whether the presence of NMS in PD patients is associated with or independent from the severity of MS considering confounders.

METHODS

The registry of PD patients from seven facilities in Japan was used. Multiple logistic regression was performed with each domain and item of the Non-motor Symptoms Scale (NMSS) as objective variables. Severity of motor symptoms was assessed by Hoehn & Yahr stage (HY stage) as an explanatory variable. The analysis was adjusted for sex, age, disease duration, presence/absence of wearing off and dyskinesia, clinical phenotypes and Levodopa equivalent daily dose.

RESULTS

A total of 1037 patients were analyzed. Analysis by NMSS domain showed higher odds ratios (ORs) in patients with higher HY stages compared with patients with lower HY stages for domains D1 (cardiovascular), D2 (sleep/fatigue), D3 (mood/apathy), D4 (perceptual problems/hallucinations), D5 (attention/memory), and D6 (gastrointestinal) (ORs: 1.54-2.72, P < .05). However, only domains D7 (urinary) and D8 (sexual dysfunction) were not associated with HY stage. Item 2 (fainting) and Item 14 (delusions) showed higher ORs in the HY stage 4-5 (ORs: 9.95 and 5.92, P < .05).

CONCLUSIONS

Most NMS worsened with exacerbation of MS in PD patients, however some NMS domains were also affected with other factors. These findings contribute to the understanding of the clinical picture of PD and may improve personalized medicine and research in PD.

Neuropsychiatric aspects of Parkinson disease psychopharmacology: Insights from circuit dynamics

Parkinson disease (PD) is a neurodegenerative disorder with a complex pathophysiology characterized by the progressive loss of dopaminergic neurons within the substantia nigra. Persons with PD experience several motoric and neuropsychiatric symptoms. Neuropsychiatric features of PD include depression, anxiety, psychosis, impulse control disorders, and apathy. In this chapter, we will utilize the National Institutes of Mental Health Research Domain Criteria (RDoC) to frame and integrate observations from two prevailing disease constructions: neurotransmitter anomalies and circuit physiology. When there is available evidence, we posit how unified translational observations may have clinical relevance and postulate importance outside of PD. Finally, we review the limited evidence available for pharmacologic management of these symptoms.

Damaged Insula Network Contributes to Depression in Parkinson's Disease

BACKGROUND

Depression is common in patients with Parkinson's disease (PD). Our previous studies suggest that depressed PD patients have altered insula structures. It is, however, still unknown whether the altered structures cause disruption of insula functional networks, further contributing to depression in PD.

METHODS

In the present study, 17 depressed PD patients, 17 non-depressed PD patients, and 17 normal controls were enrolled. All subjects went through neurological and psychiatric clinical assessments. Resting-state functional magnetic resonance imaging and seed-based insula functional analyses were performed to examine the insula functional connectivity alterations in PD patients.

RESULTS

We found that compared with normal controls, PD patients exhibited significantly decreased insula functional connectivity widely across the whole brain. Compared with non-depressed PD patients, depressed patients showed further decreased functional connectivity in the middle frontal gyrus and inferior parietal lobe. Furthermore, connectivity between the left anterior insula and middle frontal gyrus was positively correlated with the cognitive scale score.

CONCLUSION

These results suggest that insula networks were severely damaged in PD patients, and that the disrupted connection between the salience network and executive control network might contribute to depression in PD.

Sex differences in Parkinson's disease presentation and progression

INTRODUCTION

Females have a reduced risk of Parkinson's disease (PD). However, it is unclear if sex is a prognostic factor. We aimed to examine differences in presentation, physician- and patient-reported PD outcomes, and progression by sex in a large clinical cohort.

METHODS

This study was a secondary analysis of a cohort of PD patients seen at a tertiary care center. Sociodemographic and clinical characteristics, treatment, care timing, and outcomes were examined by sex. Sex differences in progression of impairment, disability, and health-related quality of life (HRQoL) were tested with five-year piecewise linear mixed-effects models. A mediation analysis assessed drivers of sex differences.

RESULTS

The study included 914 males and 549 females. Females had significantly less social support, more psychological distress, and worse self-reported (but not physician-reported) disability and HRQoL at initial PD care visits, compared to males. Addressing anxiety symptoms may attenuate this difference. PD progression sex differences were minimal.

CONCLUSION

PD progression does not differ by sex, yet patient-reported measures of disease severity are worse in females than males. To attenuate this sex difference in disease experience, psychological distress screening and management, particularly targeting females, should be implemented as part of PD clinical care.

Symptom burden among individuals with Parkinson disease: A national survey

Objective

To explore disease burden in Parkinson disease (PD) by evaluating the prevalence of symptoms and key disease milestones (critical events, e.g., hospitalization or frequent falls) and their association with quality of life (QOL) in those with PD.

Methods

We created and pretested an online needs assessment survey to evaluate the clinical characteristics, QOL, symptom prevalence, and critical event frequency among those with PD. We recruited individuals with self-reported Hoehn and Yahr stage II-V PD through online postings and email through the Davis Phinney Foundation. We used logistic regression to evaluate the association between a large number of uncontrolled symptoms and events on QOL.

Results

A total of 612 individuals (mean age 70.1 years, 49.8% women) completed the survey. Among respondents, 13.6% reported poor QOL. Nearly 20% of respondents reported >3 falls, and 15% of respondents had been hospitalized over the previous 6 months. Participants had an average of 5.1 uncontrolled symptoms, with 86.1% of respondents reporting at least 1 uncontrolled symptom; more than 10% of respondents reported >10 uncontrolled symptoms. Depression, confusion, pain, and bothersome hallucinations were associated with poor QOL among the cohort.

Conclusions

In this national survey of individuals with PD, we identified poor QOL, frequent critical events, and numerous uncontrolled symptoms among a substantial proportion of respondents. Although motor symptoms were common, only nonmotor symptoms were associated with poor QOL. Many of these symptoms and events are treatable or preventable, highlighting the need for better identification and management to improve QOL among those with PD.

Relationships between sleep quality, depressive symptoms and MCI diagnosis: A path analysis

BACKGROUND

This study examined the complex relationships between sleep quality, depressive symptoms, and cognitive decline in older adults. We hypothesised that older age, lower education and greater medical comorbidities would each be associated with increased mild cognitive impairment (MCI) diagnosis risk through indirect effects via poorer sleep quality, and greater depressive symptomology.

METHODS

540 adults 44 years and over were recruited at the Brain and Mind Centre, Sydney, Australia. Participants underwent comprehensive psychiatric, neuropsychological, and medical assessment. Subjective sleep quality, current depressive symptomatology, and current medical burden were assessed.

RESULTS

There were significant indirect effects of each of age, comorbidities and education, that operated via both sleep and depression. Younger age, greater comorbidities and fewer years' education each predicted greater chance of MCI diagnosis via poorer sleep and in turn higher depressive symptomatology. Additionally, there was a significant direct effect of older age on MCI.

LIMITATIONS

The current study is cross-sectional and cannot determine whether poorer sleep quality and greater depressive symptomatology precede or arise as a result of the onset of cognitive decline in later-life. A longitudinal design may allow further explication of these relationships.

CONCLUSIONS

Both sleep and depression are linked with cognitive decline in older adults, with sleep disturbance appearing to predict depressive symptoms. These findings have implications for the management of MCI. Both greater depression symptomatology and sleep disturbance were shown to predict the risk of MCI diagnosis, with this effect strongest in those that are younger. Improved early detection and treatment of sleep problems in older adults may help prevent depressive symptom manifestation or exacerbation, in turn potentially reducing the risk of subsequent cognitive decline.