Depressive Symptoms are Frequent in Atypical Parkinsonian Disorders

The enigma of depression in corticobasal degeneration, a frequent but poorly understood co-morbidity

Depression is one of the most frequent neuropsychiatric symptoms in corticobasal degeneration (CBD), a rare, sporadic, and late-onset progressive neurodegenerative disorder of unknown etiology. It is clinically characterized by a levodopa-poorly responsible akinetic-rigid syndrome, apraxia, limb dystonia, cognitive, mood, behavioral, and language disorders. This 4-repeat (4R) tauopathy is morphologically featured by asymmetric frontoparietal atrophy, neuronal loss, and gliosis in cortex and subcortex including substantia nigra, ballooned/achromatic neurons with filamentous 4R tau aggregates in cortex and striatum, widespread thread-like structures, pathognomonic "astroglial plaques", "tufted astrocytes", and numerous "coiled bodies" (in astrocytes and oligodendroglia) in cerebral white matter. CBD is non-specific, as pathologically proven cases include several clinical phenotypes. Pubmed and Google Scholar were systematically analyzed until October 2023, with focus on the prevalence, clinical manifestation, neuroimaging data, and treatment options of depression in CBD. Its prevalence is about 30-40% which is more frequent than in most other atypical parkinsonian syndromes. Depression usually does not correlate with motor and other clinical parameters, suggesting different pathophysiological mechanisms. Asymmetric atrophy and hypometabolism of frontoparietal cortical areas are associated with disruption of fronto-subcortical circuits, nigrostriatal dopaminergic, and cholinergic deficiency. Since no specific neuroimaging, neuropathological, or biomarker studies of depression in CBD are available, its pathobiological mechanisms and pathogenesis are poorly understood. Antidepressive therapy may be useful, but is often poorly tolerated. Depression in CBD, like in other parkinsonian syndromes, may be related to multi-regional patterns of cerebral disturbances and complex pathogenic mechanisms that deserve further elucidation as a basis for early diagnosis and adequate treatment to improve the quality of life in this fatal disease.

Depression in dementia with Lewy bodies: a critical update

Depression with an estimated prevalence of 35% is a frequent manifestation of dementia with Lewy bodies (DLB), having negative effects on cognitive performance and life expectancy, yet the underlying neurobiology is poorly understood and most likely heterogeneous. Depressive symptoms in DLB can occur during the clinical course and, together with apathy, is a common prodromal neuropsychiatric symptom of this neurocognitive disorder in the group of Lewy body synucleinopathies. There are no essential differences in the frequency of depression in DLB and Parkinson disease-dementia (PDD), while its severity is up to twice as high as in Alzheimer disease (AD). Depression in DLB that is frequently underdiagnosed and undertreated, has been related to a variety of pathogenic mechanisms associated with the basic neurodegenerative process, in particular dysfunctions of neurotransmitter systems (decreased monoaminergic/serotonergic, noradrenergic and dopaminergic metabolism), α-synuclein pathology, synaptic zinc dysregulation, proteasome inhibition, gray matter volume loss in prefrontal and temporal areas as well as dysfunction of neuronal circuits with decreased functional connectivity of specific brain networks. Pharmacotherapy should avoid tricyclic antidepressants (anticholinergic adverse effects), second-generation antidepressants being a better choice, while modified electroconvulsive therapy, transcranial magnetic stimulation therapy and deep brain stimulation may be effective for pharmacotherapy-resistant cases. Since compared to depression in other dementias like Alzheimer disease and other parkinsonian syndromes, our knowledge of its molecular basis is limited, and further studies to elucidate the heterogeneous pathogenesis of depression in DLB are warranted.

Neuropsychological profile of CSF1R-related leukoencephalopathy

Introduction

The neuropsychological profile of CSF1R-related leukoencephalopathy (CRL) is undefined. This study defines the profile, contrasts it with that of other dementia syndromes, and highlights measures sensitive to cognitive impairment.

Methods

We administered a standardized battery of neuropsychological tests to five consecutive CRL cases.

Results

The neuropsychological profile of CRL reflects impaired general cognitive function, processing speed, executive function, speeded visual problem solving, verbal fluency, and self-reported depression and anxiety. Confrontation naming and memory are preserved. Within cognitive domains, certain measures more frequently identified impairment than others.

Discussion

CRL impairs general cognitive function, processing speed, executive function. Language and visual problem solving may be impaired if processing speed is required. Confrontation naming and memory are uniquely preserved, contrasting CRL to other dementia syndromes. Cognitive screens excluding processing speed and executive function may not detect CRL cognitive manifestations. Findings sharply define cognitive impairment of CRL and inform cognitive test selection.

Pathomechanisms of depression in progressive supranuclear palsy

Depression is one of the most frequent neuropsychiatric symptoms in progressive supranuclear palsy (PSP), a four-repeat tauopathy and most common atypical parkinsonian disorder, but its pathophysiology and pathogenesis are poorly understood. Pubmed/Medline was systematically analyzed until January 2023, with focus on the prevalence, major clinical features, neuroimaging findings and treatment options of depression in PSP. The average prevalence of depression in PSP is around 50%; it does usually not correlate with most other clinical parameters. Depression is associated with multi-regional patterns of morphometric gray matter variations, e.g., reduced thickness of temporo-parieto-occipital cortices, and altered functional orbitofrontal and medial frontal circuits with disturbances of mood-related brain networks. Unfortunately, no specific neuropathological data about depression in PSP are available. Antidepressive and electroconvulsive therapies are effective in improving symptoms; the efficacy of transcranial stimulation needs further confirmation. Depression in PSP is a common symptom, related to multi-regional patterns of cerebral disturbances and complex pathogenic mechanisms that deserve further elucidation as a basis for adequate treatment to improve the quality of life in this fatal disease.

Prevalence and Correlates of Psychiatric Comorbidity and Multimorbidity in Parkinson's Disease and Atypical Parkinsonian Syndromes

PURPOSE

Psychiatric comorbidity in Parkinson's disease (PD) and atypical parkinsonian syndromes (APS) has been consistently associated with poor outcomes. However, the co-occurrence of multiple psychiatric disorders has been sparsely studied. This study examines the prevalence, patterns, and correlates of psychiatric comorbidity and multimorbidity among in-patients hospitalised with PD/APS.

METHODS

Patients (N-110 [PD-71, APS-39]) underwent a single cross-sectional assessment. Psychiatric comorbidity was examined using the Mini International Neuropsychiatric Interview. Other domains assessed include sleep disorders, quality of life, and caregiver burden.

STATISTICAL ANALYSIS

In addition to descriptive statistics, multinomial logistic regression was used to examine the effect of sociodemographic and clinical factors on comorbidities.

RESULTS

The prevalence of psychiatric comorbidity in patients with PD and APS was 77.00% and 71.79%, with approximately half of those having co-occurrence of multiple psychiatric disorders. In both disorders, depression was the most common, followed by anxiety disorder. The two commonest patterns of multimorbidity reported in PD were the combination of depression and anxiety disorder, followed by the combination of psychosis, depression, and anxiety, with the order being reversed in APS. When compared to those without, those with single psychiatric comorbidity had higher odds of having REM sleep behaviour disorder and caregiver stress. Those with multiple psychiatric comorbidities had higher odds of being female, higher UPDRS part-1 scores, REM sleep behaviour disorder, poor sleep quality, and caregiver stress.

CONCLUSION

Psychiatric illness is highly comorbid among patients with PD/APS, with most having multiple co-occurring psychiatric illnesses. Clinicians must be aware to ensure early detection and intervention.

Non-motor symptoms in multiple system atrophy: A comparative study with Parkinson's disease and progressive supranuclear palsy

Background

Non-motor symptoms (NMS) are compulsory clinical features for the clinical diagnosis of multiple system atrophy (MSA), some of which precede motor symptoms onset. To date, few studies have systematically investigated NMS in MSA and the timing of presenting NMS as the disease progresses. Clinically, MSA is difficult to be differentiated from Parkinson's disease (PD) and progressive supranuclear palsy (PSP), and the differences in NMS between MSA and PD/PSP remain unclear. The aim of this study was to compare the burden of NMS between MSA and PD/PSP and to delineate the timing of NMS presentation relative to the onset of motor symptoms in MSA.

Methods

A total of 61, 87, and 30 patients with MSA, PD, and PSP, respectively, were enrolled in this study. NMS was systematically assessed in all patients using the NMS scale (NMSS), and the onset of NMS relative to the onset of motor symptoms in MSA was investigated.

Results

MSA group had higher total NMSS scores (82.15 ± 46.10) than the PD (36.14 ± 30.78) and PSP (50.30 ± 55.05) groups (p < 0.001 overall). The number distribution pattern of the NMS was significantly different among the three parkinsonian disorders (p < 0.001 overall). In total, 85.2% of patients with MSA had more than 10 NMS, which was significantly higher than PD (28.7%) and PSP (33.3%). The frequency and scores of many NMSS subdomains and symptoms were higher in MSA than in PD and PSP (all p < 0.05). Multivariate logistic regression analysis revealed that patients with fainting, lack of motivation, swallowing, and loss of sexual interest could be attributed to MSA rather than PD or PSP, while patients with loss of concentration and forgetfulness were characteristic features of PD or PSP rather than MSA. REM-sleep behavior disorder (RBD), constipation, problems having sex, and loss of sexual interest preceded the motor symptoms onset of MSA by 2.81 ± 4.51, 1.54 ± 6.32, 1.35 ± 4.70, and 0.45 ± 3.61 years, respectively.

Conclusion

The NMS spectrum in MSA differs from that of PD and PSP. Patients with MSA have a higher NMS burden than patients with PD or PSP. RBD, constipation, problems having sex, and loss of sexual interest may become early diagnostic clinical markers of MSA.

Pathomechanisms of depression in multiple system atrophy

Multiple system atrophy (MSA) is a rapidly progressing neurodegenerative disorder of uncertain etiology that is characterized by various combinations of Parkinsonism, autonomic, cerebellar and motor dysfunctions, with poor prognosis. Little is known about modifiable factors, such as depression, that has negative effects on quality of life in MSA. Depression, with an estimated prevalence of about 43%, is among the most common neuropsychiatric disorders in MSA similar to other atypical Parkinsonian disorders, the frequency of which is associated with increased disease progression, disease severity and autonomic dysfunctions. Depression in MSA, like in Parkinson disease, has been related to a variety of pathogenic mechanisms associated with the underlying neurodegenerative process, such as involvement of serotonergic neuron groups in the brainstem, prefrontal cortical dysfunctions, and altered functional fronto-temporal-thalamic connectivities with disturbances of mood related and other essential resting-state brain networks. The pathophysiology and pathogenesis of depression in MSA, as in other degenerative movement disorders, are complex and deserve further elucidation as a basis for adequate treatment to improve the quality of life in this fatal disease.

A Systematic Review of Apathy and Depression in Progressive Supranuclear Palsy

Depression and apathy can be significant problems in progressive supranuclear palsy (PSP). Using PRISMA guidelines, this systematic review examined prevalence estimates for depression and apathy in PSP, and, how different methods of definition may influence results. 29 studies meeting inclusion/exclusion criteria were identified: 12 on depression, 9 on apathy, and 8 on both. Studies were stratified according to whether a diagnostic criteria, rating scale or screening question methodology was employed. The weighted mean prevalence was 59.7% for depression (sample size = 473) and 58.3% for apathy (sample size = 858). Results for depression using diagnostic criteria or rating scales were similar whereas screening questions were associated with considerable inconsistency. Depression prevalence appeared to be influenced by apathy but not somatic symptoms. Most apathy studies relied only on a screening question method. Depression and apathy are common in PSP but there is a need for consensus on how they are defined (both tools and cut-off scores). In particular, more studies probing apathy in greater detail than a simple screening question are required.

Depression and Apathy across Different Variants of Progressive Supranuclear Palsy

BACKGROUND

Apathy and depression commonly occur in patients with progressive supranuclear palsy (PSP)-Richardson's syndrome variant; depression often requiring treatment. Little is known, however, about apathy and depression among other PSP variants.

METHODS

We prospectively studied 97 newly diagnosed PSP patients. All were classified into a PSP variant using the 2017 Movement Disorder Society-PSP criteria and administered the Geriatric Depression and Apathy Evaluation Scales. Differences in apathy and depression frequency and severity across six variants, and secondarily across PSP-Richardson's syndrome, PSP-Cortical and PSP-Subcortical, were analyzed using ANCOVA and linear regression adjusting for disease severity.

RESULTS

Depression (55%) was more common than apathy (12%). PSP-Speech/Language (PSP-SL) variant had the lowest depression frequency (13%) and lower depression scores than the other variants. No differences in apathy frequency/severity were identified.

CONCLUSION

PSP-SL patients may have less depression compared to PSP-Richardson's syndrome and other PSP variants.

Preferences for Communication About End-of-Life Care in Atypical Parkinsonism

BACKGROUND

Studies on preferences regarding discussions on end-of-life care (EOLC), advance care planning (ACP), medical assistance in dying (MAiD), and brain donation have not yet been conducted in patients with atypical parkinsonism (AP).

OBJECTIVE

The aim of this study was to know the preferences of patients with AP regarding discussions on EOLC, ACP, MAiD, and brain donation.

METHODS

This cross-sectional study was conducted in patients clinically diagnosed with AP. An adapted questionnaire that assessed various potential factors that affect patients' preferences regarding EOLC and ACP was sent through postal mail to 278 patients.

RESULTS

A total of 90 completed questionnaires were returned. Most patients preferred to discuss at the time of diagnosis information about the disease, its natural course, treatment options, and prognosis. In contrast, they preferred that EOLC and ACP be discussed when the disease has progressed. No demographic or disease-related factors were found to be predictors of the patient's preferences. Notably, most patients (63.3%) had previous actual discussions on these issues. Less than a third of patients were open to discussions about MAiD and brain donation; older age and the importance of spirituality and religion decreased the odds of discussing these.

CONCLUSIONS

Our study demonstrates that patients with AP have preferences regarding the timing of the discussion of the different themes surrounding EOLC and ACP. A needs-based approach in initiating and conducting timely discussions on these difficult but essential issues is proposed. A thorough explanation and recognition of a patient's beliefs are recommended when initiating conversations about MAiD and brain donation. © 2021 International Parkinson and Movement Disorder Society.

Suicidal and death ideation in patients with progressive supranuclear palsy and corticobasal syndrome

OBJECTIVE

A large proportion of patients with atypical parkinsonian syndromes suffer from depression, an antecedent of suicide. This study aimed to explore the prevalence and clinical correlates of suicidal and death ideation (SDI) in patients with Progressive Supranuclear Palsy (PSP) and Corticobasal Syndrome (CBS), as well as compare the differences with patients with Parkinson's disease (PD).

METHODS

This was a case-control, cross-sectional study. SDI was diagnosed based on the assessment of the Hamilton Depression Rating Scale (HRDS). The prevalence of SDI among patients with PD, PSP, and CBS (n = 3400, 268, and 65 respectively) were compared before and after propensity score matching (PSM). A forward binary logistic regression model was used to explore the associated factors of SDI.

RESULTS

None of the patients reported suicide attempts. The prevalence of SDI in patients with PSP and CBS were 27.2% and 29.2%, respectively, which was significantly higher than that in patients with PD before and after PSM (P < 0.05). The prevalence of SDI was not significantly different among patients with PSP with different subtypes (Richardson syndrome, Parkinsonism, and other), both before and after PSM (P > 0.05). Multivariate analysis indicated that higher gait and midline score and depression were independently associated with an increased risk of SDI in patients with PSP (P < 0.05), while higher non-motor symptoms score and depression were independently associated with the occurrence of SDI in patients with CBS (P < 0.05).

CONCLUSIONS

Our study highlights the importance of screening SDI in patients with PSP and CBS.

Current Management and Emerging Therapies in Multiple System Atrophy

Multiple system atrophy (MSA) is a progressive neurodegenerative disease variably associated with motor, nonmotor, and autonomic symptoms, resulting from putaminal and cerebellar degeneration and associated with glial cytoplasmic inclusions enriched with α-synuclein in oligodendrocytes and neurons. Although symptomatic treatment of MSA can provide significant improvements in quality of life, the benefit is often partial, limited by adverse effects, and fails to treat the underlying cause. Consistent with the multisystem nature of the disease and evidence that motor symptoms, autonomic failure, and depression drive patient assessments of quality of life, treatment is best achieved through a coordinated multidisciplinary approach driven by the patient's priorities and goals of care. Research into disease-modifying therapies is ongoing with a particular focus on synuclein-targeted therapies among others. This review focuses on both current management and emerging therapies for this devastating disease.

Comparative analysis of non-motor symptoms in patients with Parkinson's Disease and atypical parkinsonisms

OBJECTIVES

After being diagnosed with idiopathic Parkinson's Disease (IPD) or Atypical Parkinsonism (AP) patients often tend to present non-motor symptoms (NMS). The aim of the study was to explore the differences between occurrence of non-motor symptoms presented by patients with IPD and AP, including sleep, autonomic, psychotic and affective disorders.

MATERIALS AND METHOD

The study included 219 patients (184 with IPD, and 35 with AP) hospitalized between 2016 and 2019 in the Department of Neurology of the Medical University of Silesia. Non-motor symptoms were evaluated using patients' medical chart reviews and NMS questionnaire. The clinical advancement of the disease was assessed using UPDRS part III, and modified Hoehn-Yahr scale (HY).

RESULTS

There were no statistically significant differences between both IPD and AP groups within the parameters of sex, age, HY and UPDRS III OFF scales. Non-motor symptoms were presented significantly often (p = 0.003) in AP patients (n = 32, 91.4 %), then in patients with IPD (n = 122, 66.3 %). Sleep disorders were significantly more prevalent in patients with idiopathic Parkinson's disease (n = 92, 50 %) than in patients with atypical parkinsonism (n = 8, 22.86 %, p = 0.0031). However, autonomic and psychotic disorders didn't show statistically significant differences in both groups.

CONCLUSION

Non-motor symptoms are frequent in both IPD and AP which makes them an integral part of both diseases. Patients with AP are more likely to present non-motor symptoms in general, but rarely they complain of sleep disorders.

Motor, cognitive and behavioral differences in MDS PSP phenotypes

INTRODUCTION

Movement Disorder Society (MDS) new diagnostic criteria for Progressive Supranuclear palsy (PSP) identifying different disease phenotypes were recently released. The aim of the present study is to report on the cognitive and behavioral features of the different phenotypes diagnosed according to the MDS criteria.

METHODS

Forty-nine PSP patients underwent an extensive battery of clinical assessments. Differences between PSP subtypes were computed with χ² or ANOVA tests. Using the z scores, subjects were classified as having normal cognition, mild cognitive impairment, single or multiple domain, and dementia. A logistic regression model was implemented to investigate the major determinants of PSP non-Richardson's syndrome phenotype.

RESULTS

Half of the cohort presented Richardson's syndrome (46.9%), followed by PSP with parkinsonism and corticobasal syndrome (22.4% and 14.2%, respectively). Richardson's syndrome and PSP with corticobasal syndrome presented a similar burden of disease. The only cognitive testing differentiating the phenotypes were semantic fluency and ideomotor apraxia. The majority of our cohort was either affected by dementia or presented normal cognition. Richardson's syndrome presented the highest rate of dementia. The only marker of PSP non-Richardson's syndrome phenotype was better performance in visuo-spatial testing, implying worse visuo-spatial abilities in PSP Richardson's syndrome.

CONCLUSION

Available clinical assessments hardly capture differences between PSP phenotypes. The cognitive testing differentiating the PSP phenotypes were semantic fluency and ideomotor apraxia. In PSP, mild cognitive impairment likely represents an intermediate step from normal cognition to dementia. The only marker of PSP non-Richardson's syndrome phenotype was better performance in visuo-spatial testing.

Effects and mechanism of epigallocatechin-3-gallate on apoptosis and mTOR/AKT/GSK-3β pathway in substantia nigra neurons in Parkinson rats

The aim of this study is to investigate the protective effect of epigallocatechin-3-gallate (EGCG) on apoptosis and mTOR/AKT/GSK-3β pathway in substantia nigra neurons in 6-dopamine-induced Parkinson rats. A total of 30 healthy male SD rats were randomly divided into control group, the Parkinson model group, and Parkinson model+EGCG treatment group. The model and EGCG groups were injected into the right striatum with 6-OHDA to establish the Parkinson model, and the control group was injected with saline only. The EGCG group was intragastrically administered with EGCG 50 mg/kg daily for 4 weeks. The rats' turns, speed, and left forelimb usage; neuron apoptosis by TUNEL; and the α-synuclein protein expression in substantia nigra by immunohistochemical staining were studied. Western blotting was used to detect the relative protein (mTOR, AKT and GSK-3β) expressions. Compared with the model group, the EGCG group significantly reduced the rotation speed; increased the left forelimb usage (P<0.01); reduced the neuron apoptosis (P<0.01); decreased α-synuclein expression (P<0.01); and decreased the mTOR, AKT, and GSK-3β protein expressions (P<0.01). EGCG can reduce neuron cell apoptosis in substantia nigra neurons in 6-OHDA-induced Parkinson rats. The mechanism might be related to mTOR/AKT/GSK-3β activation.

The Comprehensive Management of Cerebellar Ataxia in Adults

PURPOSE OF REVIEW

In this review, we present the multidisciplinary approach to the management of the many neurological, medical, social, and emotional issues facing patients with cerebellar ataxia.

RECENT FINDINGS

Our holistic approach to treatment, developed over the past 25 years in the Massachusetts General Hospital Ataxia Unit, is centered on the compassionate care of the patient and their family, empowering them through engagement, and including the families as partners in the healing process. We present the management of ataxia in adults, beginning with establishing an accurate diagnosis, followed by treatment of the multiple symptoms seen in cerebellar disorders, with a view to maximizing quality of life and effectively living with the consequences of ataxia. We discuss the importance of a multidisciplinary approach to the management of ataxia, including medical and non-medical management and the evidence base that supports these interventions. We address the pharmacological treatment of ataxia, tremor, and other associated movement disorders; ophthalmological symptoms; bowel, bladder, and sexual symptoms; orthostatic hypotension; psychiatric and cognitive symptoms; neuromodulation, including deep brain stimulation; rehabilitation including physical therapy, occupational therapy and speech and language pathology and, as necessary, involving urology, psychiatry, and pain medicine. We discuss the role of palliative care in late-stage disease. The management of adults with ataxia is complex and a team-based approach is essential.

Recognizing and treating atypical Parkinson disorders

Though less common than Parkinson's disease (PD), the atypical Parkinson disorders such as such as dementia with Lewy bodies, multiple system atrophy, progressive supranuclear palsy, and corticobasal degeneration are increasingly recognized and important to distinguish from PD. Atypical or "Parkinson-plus" disorders are multisystem disorders and generally progress more rapidly and respond poorly to current therapies compared to PD. Recent advances in our understanding of the pathophysiology of these disorders, however, have generated new interest in the development of novel diagnostics and disease-modifying therapeutics aimed at identifying and treating these disorders. In this review we discuss the clinical approach to the atypical Parkinson disorders and the recent developments in diagnostic and research criteria that take into account the phenotypic heterogeneity and advances in our understanding of the pathophysiology of these disorders.

Advances in the pharmacotherapeutic management of dementia with Lewy bodies

INTRODUCTION

Dementia with Lewy bodies (DLB) is the second most common type of dementia in people over 65 years of age. Given the complex clinical phenotype, the management of DLB may be challenging, especially considering that there is limited evidence about specific interventions, and there are currently no Food and Drug Administration (FDA)/European Medicines Agency (EMA)-approved medications.

AREAS COVERED

This article provides an overview of the current pharmacotherapy in DLB and gives review to the most recent drug candidates in clinical trials.

EXPERT OPINION

Commonly prescribed drugs are primarily aimed at treating the most troublesome clinical features of DLB. Although these medications provide some benefit to symptoms, there is, unfortunately, a lack of DLB-specific evidence on effective treatments and their off-label use. Indeed, most treatments used come from clinical trials on patients with Alzheimer's disease or Parkinson's disease. Thus, there is an urgent need for randomized clinical trials in DLB patients. Despite several challenges, potential new drugs are in ongoing clinical trials; furthermore, as our understanding of molecular and cellular mechanisms underlying DLB broaden, it is likely that we will identify novel drug targets for the development of better and more effective symptomatic products and disease-modifying therapies.

REM Sleep Behavior Disorder (RBD) in Dementia with Lewy Bodies (DLB)

Rapid eye movement sleep behavior disorder (RBD) is a parasomnia, with abnormal dream-enacting behavior during the rapid eye movement (REM) sleep. RBD is either idiopathic or secondary to other neurologic disorders and medications. Dementia with Lewy bodies (DLB) is the third most common cause of dementia, and the typical clinical presentation is rapidly progressive cognitive impairment. RBD is one of the core features of DLB and may occur either in advance or simultaneously with the onset of DLB. The association between RBD with DLB is widely studied. Evidences suggest that both DLB and RBD are possibly caused by the shared underlying synucleinopathy. This review article discusses history, clinical manifestations, possible pathophysiologies, and treatment of DLB and RBD and provides the latest updates.

Nonmotor Features in Atypical Parkinsonism

Atypical parkinsonism (AP) comprises mainly multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD), which are distinct pathological entities, presenting with a wide phenotypic spectrum. The classic syndromes are now called MSA-parkinsonism (MSA-P), MSA-cerebellar type (MSA-C), Richardson's syndrome, and corticobasal syndrome. Nonmotor features in AP have been recognized almost since the initial description of these disorders; however, research has been limited. Autonomic dysfunction is the most prominent nonmotor feature of MSA, but also gastrointestinal symptoms, sleep dysfunction, and pain, can be a feature. In PSP and CBD, the most prominent nonmotor symptoms comprise those deriving from the cognitive/neuropsychiatric domain. Apart from assisting the clinician in the differential diagnosis with Parkinson's disease, nonmotor features in AP have a big impact on quality of life and prognosis of AP and their treatment poses a major challenge for clinicians.