Chronobiology of Parkinson's disease: Past, present and future

Prevalence and associations of self-reported sleep problems in a large sample of patients with Parkinson's disease

Sleep problems are important comorbid features of, and risk factors for, neurodegenerative diseases such as Parkinson's disease (PD). To assess the prevalence and associations of sleep problems in patients with PD we analysed data from almost 54,000 participants in the Fox Insight study, including data from 38,588 patients with PD. Sleep problems are common in PD, with ~84% of respondents with PD reporting difficulty falling or staying asleep. Experiences of insomnia, restless leg syndrome, vivid dreams, acting out dreams, and the use of sleep medication are over-represented in patients with PD compared with matched healthy controls. Male sex and PD onset before the age of 50 were also associated with a greater risk of sleep problems. A physician diagnosis of insomnia was associated with more symptoms of depression, impairment of cognition-dependent independence, and a lower quality of life. Sleep problems were also associated with a higher prevalence of OFF periods compared with PD patients without sleep problems. 6.7% of PD patients endorsed sleep complaints as their most bothersome symptom, and reported non-specific poor sleep quality as the most common sleep problem. These patients also had a better quality of life and lower depression and cognitive impairments than patients for whom postural instability was their most bothersome symptom, indicating the relative burden of sleep problems is contextualised by the severity of motor symptoms. Overall, these findings reinforce the high prevalence of sleep problems in a very large sample of PD patients, and indicate important associations of sleep problems with daily function and quality of life in PD.

The Use of Melatoninergic Antidepressants for Stabilization of Remission in Depression Comorbid with Alcohol Abuse, Anxiety or Neuropsychiatric Disorders: A Systematic Review

BACKGROUND

Depression is one of the most common mental disorders and is associated with a significant increase in the risk of mental and somatic comorbidities. The chronobiological theory of the pathogenesis of depression explains the relationship between the symptoms of depression and disturbance of circadian rhythm regulation. Disrupted circadian rhythms are also observed in other disorders such as alcohol use disorder, anxiety disorders, epilepsy, and Parkinson's disease. Therefore, there is a growing interest in the use of medications with a melatoninergic mechanism of action in the treatment of depression comorbid with the aforementioned disorders.

AIM

This review aims to systematically examine the evidence for the use of melatoninergic antidepressants (agomelatine and fluvoxamine) in the treatment of depression comorbid with alcohol abuse, anxiety disorders (including phobic anxiety, panic, and generalized anxiety disorders), or neuropsychiatric disorders (such as epilepsy and Parkinson's disease).

METHODS

This systematic review included experimental studies, systematic reviews, and meta-analyses published in English and Russian, which examined the use of fluvoxamine and agomelatine in adult patients with recurrent depressive disorder (ICD-10) or major depressive disorder (DSM-5) comorbid with alcohol abuse, anxiety or neuropsychiatric disorders. The search was conducted in the PubMed, Cochrane Library and eLIBRARY scientific databases. The quality of the selected studies was assessed using the Cochrane Risk of Bias tool, which is used to evaluate the risk of systematic errors in clinical studies. The results were presented as a narrative synthesis and grouped by the comorbidities evaluated.

RESULTS

A total of 20 articles were reviewed (with a pooled sample size of n=1,833 participants). The results suggest that melatoninergic antidepressants might help in reducing depressive and anxiety symptoms, improve sleep, decrease alcohol cravings, and alleviate the severity of motor symptoms in Parkinson's disease. Moreover, the use of pharmacogenetic testing to select the medication and dosage may enhance its therapeutic effectiveness.

CONCLUSION

The review demonstrates a significant lack of clinical data and guidelines on the use of melatoninergic medications for the treatment of depression comorbid with other disorders. In this regard, it is currently difficult to draw a definitive conclusion regarding the efficacy and safety of agomelatine and fluvoxamine in the treatment of these comorbidities. Available studies suggest an improvement in the clinical manifestations of the comorbidities. Future research directions might include the development and implementation of double-blind, randomized clinical trials to study the use of melatoninergic medications in patients with depression comorbid with other disorders.

Decreased Cortical Sulcus Depth in Parkinson's Disease with Excessive Daytime Sleepiness

INTRODUCTION

Excessive daytime sleepiness (EDS), a prevalent non-motor symptom in Parkinson's disease (PD), significantly impacts the quality of life for PD patients and elevates the risks of injury. Our study is to investigate the altered cortical surface morphology characteristics in PD patients with EDS (PD-EDS).

METHODS

Clinical data and magnetic resonance imaging were obtained from the Parkinson's Progression Marker Initiative database, comprising 36 PD-EDS and 98 PD patients without EDS (PD-nEDS). The computational anatomy toolbox was utilized to derive sulcus depth (SD) and deep grey matter (GM) nuclei volumes.

RESULTS

PD-EDS patients exhibited significantly decreased SD values in the right caudal middle frontal gyrus, pars opercularis, and superior temporal cortex relative to PD-nEDS patients. However, no significant differences in deep GM nuclei volumes were identified. Receiver operating characteristic (ROC) curve analyses further revealed that these cortical SD values could potentially serve as a screening index for distinguishing PD-EDS from PD-nEDS. Additionally, although PD-EDS patients had a longer disease duration and poorer performance in motor function and depression compared to PD-nEDS patients, these factors were included as covariates in the neuroimaging analyses.

CONCLUSION

Our study findings demonstrated that decreased cortical SD values might induce sleep-wake state instability and contribute to the pathophysiological mechanisms of EDS in early-stage PD.

Blunted Melatonin Circadian Rhythm in Parkinson's Disease: Express Bewilderment

Melatonin (MTN) is a neuro-hormone released from the pineal gland. MTN secretion is regulated by different neuronal circuits, including the retinohypothalamic tract and suprachiasmatic nucleus (SCN), which are affected by light. MTN is neuroprotective in various neurodegenerative diseases, including Parkinson's disease (PD). MTN circulating level is highly blunted in PD. However, the underlying causes were not fully clarified. Thus, the present review aims to discuss the potential causes of blunted MTN levels in PD. Distortion of MTN circadian rhythmicity in PD patients causies extreme daytime sleepiness. The underlying mechanism for blunted MTN response may be due to reduction for light exposure, impairment of retinal light transmission, degeneration of circadian pacemaker and dysautonomia. In conclusion, degeneration of SCN and associated neurodegeneration together with neuroinflammation and activation of NF-κB and NLRP3 inflammasome, induce dysregulation of MTN secretion. Therefore, low serum MTN level reflects PD severity and could be potential biomarkers. Preclinical and clinical studies are suggested to clarify the underlying causes of low MTN in PD.

Fighting Against the Clock: Circadian Disruption and Parkinson's Disease

Circadian disruption is being increasingly recognized as a critical factor in the development and progression of Parkinson's disease (PD). This review aims to provide an in-depth overview of the relationship between circadian disruption and PD by exploring the molecular, cellular, and behavioral aspects of this interaction. This review will include a comprehensive understanding of how the clock gene system and transcription-translation feedback loops function and how they are diminished in PD. The article also discusses the role of clock genes in the regulation of circadian rhythms, as well as the impact of clock gene dysregulation on mitochondrial function, oxidative stress, and neuroinflammation, including the microbiota-gut-brain axis, which have all been proposed as being crucial mechanisms in the pathophysiology of PD. Finally, this review highlights potential therapeutic strategies targeting the clock gene system and circadian rhythm for the treatment of PD.

Non-Pharmacological Interventions for Depression and Anxiety in Parkinson's Disease

Non-pharmacological interventions, including cognitive-behavioral therapy (CBT), non-invasive brain stimulation (NIBS), electroconvulsive therapy (ECT), light therapy (LT), and physical rehabilitation/exercise, have shown promise as effective approaches to treat symptoms of depression and anxiety in individuals with Parkinson's disease (PD). In this narrative literature overview, we discuss the state-of-the-art regarding these treatment options and address future perspectives for clinical practice and research. Non-pharmacological interventions hold promise to treat depression and anxiety in PD. There is meta-analytic evidence for the efficacy of CBT, NIBS, ECT, LT, and exercise on improving depressive symptoms. For the treatment of anxiety symptoms, CBT shows large effects but scientific evidence of other non-pharmacological interventions is limited. Importantly, these treatments are safe interventions with no or mild side-effects. More research is needed to tailor treatment to the individuals' needs and combined interventions may provide synergistic effects.We conclude that non-pharmacological interventions should be considered as alternative or augmentative treatments to pharmacological and neurosurgical approaches for the treatment of depression and anxiety in individuals with PD.

Effectiveness of music-based interventions for cognitive rehabilitation in Parkinson's disease: a systematic review of randomized controlled clinical trials

BACKGROUND

Music-based interventions are promising for cognitive rehabilitation in Parkinson's disease; however, systematic reviews covering the topic are scarce.

OBJECTIVE

To analyze the effectiveness of music-based interventions for cognitive rehabilitation in PD.

METHOD

Systematic review study based on PRISMA criteria. The descriptors Parkinson's disease, Parkinson's disease, idiopathic Parkinson's disease, music-based interventions, music therapy, music training, auditory stimulation, music, rhythm, rhythmic, cognition, and cognitive were used. Five databases were searched PubMed/MEDLINE, PsycInfo, Scopus, Web of Science, and Cochrane in May 2022. Only randomized controlled trials with no limit on publication date or language were included. Risk of bias was assessed following Cochrane Collaboration criteria for development of systematic intervention reviews.

RESULTS

Nine hundred nineteen articles were found by the descriptors; 266 were excluded for being repeated; 650 for not meeting the inclusion criteria. The remaining three articles were included and analyzed. The interventions consisted of practices with emphasis on rhythm and were conducted in groups. Risks of important biases were observed, such as lack of blinding in the allocation of participants and in the assessment of outcomes, as well as incomplete data for some outcomes.

CONCLUSION

Overall, the results showed no evidence of efficacy of music-based interventions for cognitive outcomes in PD.

Melatonin as a Chronobiotic/Cytoprotective Agent in REM Sleep Behavior Disorder

Dream-enactment behavior that emerges during episodes of rapid eye movement (REM) sleep without muscle atonia is a parasomnia known as REM sleep behavior disorder (RBD). RBD constitutes a prodromal marker of α-synucleinopathies and serves as one of the best biomarkers available to predict diseases such as Parkinson disease, multiple system atrophy and dementia with Lewy bodies. Most patients showing RBD will convert to an α-synucleinopathy about 10 years after diagnosis. The diagnostic advantage of RBD relies on the prolonged prodromal time, its predictive power and the absence of disease-related treatments that could act as confounders. Therefore, patients with RBD are candidates for neuroprotection trials that delay or prevent conversion to a pathology with abnormal α-synuclein metabolism. The administration of melatonin in doses exhibiting a chronobiotic/hypnotic effect (less than 10 mg daily) is commonly used as a first line treatment (together with clonazepam) of RBD. At a higher dose, melatonin may also be an effective cytoprotector to halt α-synucleinopathy progression. However, allometric conversion doses derived from animal studies (in the 100 mg/day range) are rarely employed clinically regardless of the demonstrated absence of toxicity of melatonin in phase 1 pharmacological studies with doses up to 100 mg in normal volunteers. This review discusses the application of melatonin in RBD: (a) as a symptomatic treatment in RBD; (b) as a possible disease-modifying treatment in α-synucleinopathies. To what degree melatonin has therapeutic efficacy in the prevention of α-synucleinopathies awaits further investigation, in particular multicenter double-blind trials.