Deep Brain Stimulation and Sleep-Wake Disturbances in Parkinson Disease: A Review

Role of the globus pallidus in motor and non-motor symptoms of Parkinson's disease

The globus pallidus plays a pivotal role in the basal ganglia circuit. Parkinson's disease is characterized by degeneration of dopamine-producing cells in the substantia nigra, which leads to dopamine deficiency in the brain that subsequently manifests as various motor and non-motor symptoms. This review aims to summarize the involvement of the globus pallidus in both motor and non-motor manifestations of Parkinson's disease. The firing activities of parvalbumin neurons in the medial globus pallidus, including both the firing rate and pattern, exhibit strong correlations with the bradykinesia and rigidity associated with Parkinson's disease. Increased beta oscillations, which are highly correlated with bradykinesia and rigidity, are regulated by the lateral globus pallidus. Furthermore, bradykinesia and rigidity are strongly linked to the loss of dopaminergic projections within the cortical-basal ganglia-thalamocortical loop. Resting tremors are attributed to the transmission of pathological signals from the basal ganglia through the motor cortex to the cerebellum-ventral intermediate nucleus circuit. The cortico-striato-pallidal loop is responsible for mediating pallidi-associated sleep disorders. Medication and deep brain stimulation are the primary therapeutic strategies addressing the globus pallidus in Parkinson's disease. Medication is the primary treatment for motor symptoms in the early stages of Parkinson's disease, while deep brain stimulation has been clinically proven to be effective in alleviating symptoms in patients with advanced Parkinson's disease, particularly for the movement disorders caused by levodopa. Deep brain stimulation targeting the globus pallidus internus can improve motor function in patients with tremor-dominant and non-tremor-dominant Parkinson's disease, while deep brain stimulation targeting the globus pallidus externus can alter the temporal pattern of neural activity throughout the basal ganglia-thalamus network. Therefore, the composition of the globus pallidus neurons, the neurotransmitters that act on them, their electrical activity, and the neural circuits they form can guide the search for new multi-target drugs to treat Parkinson's disease in clinical practice. Examining the potential intra-nuclear and neural circuit mechanisms of deep brain stimulation associated with the globus pallidus can facilitate the management of both motor and non-motor symptoms while minimizing the side effects caused by deep brain stimulation.

Insomnia in Parkinson's Disease: Causes, Consequences, and Therapeutic Approaches

Sleep disorders represent prevalent non-motor symptoms in Parkinson's disease (PD), affecting over 90% of the PD population. Insomnia, characterized by difficulties in initiating and maintaining sleep, emerges as the most frequently reported sleep disorder in PD, with prevalence rates reported from 27 to 80% across studies. Insomnia not only significantly impacts the quality of life of PD patients but is also associated with cognitive impairment, motor disabilities, and emotional deterioration. This comprehensive review aims to delve into the mechanisms underlying insomnia in PD, including neurodegenerative changes, basal ganglia beta oscillations, and circadian rhythms, to gain insights into the neural pathways involved. Additionally, the review explores the risk factors and comorbidities associated with insomnia in PD, providing valuable insights into its management. Special attention is given to the challenges faced by healthcare providers in delivering care to PD patients and the impact of caregiving roles on patients' quality of life. Overall, this review provides a comprehensive understanding of insomnia in PD and highlights the importance of addressing this common sleep disorder in PD patients.

Pain-Insomnia-Depression Syndrome: Triangular Relationships, Pathobiological Correlations, Current Treatment Modalities, and Future Direction

Pain-insomnia-depression syndrome (PIDS) is a complex triad of chronic pain, insomnia, and depression that has profound effects on an individual's quality of life and mental health. The pathobiological context of PIDS involves complex neurobiological and physiological mechanisms, including alterations in neurotransmitter systems and impaired pain processing pathways. The first-line therapeutic approaches for the treatment of chronic pain, depression, and insomnia are a combination of pharmacological and non-pharmacological therapies. In cases where patients do not respond adequately to these treatments, additional interventions such as deep brain stimulation (DBS) may be required. Despite advances in understanding and treatment, there are still gaps in knowledge that need to be addressed. To improve our understanding, future research should focus on conducting longitudinal studies to uncover temporal associations, identify biomarkers and genetic markers associated with PIDS, examine the influence of psychosocial factors on treatment responses, and develop innovative interventions that address the complex nature of PIDS. The aim of this study is to provide a comprehensive overview of these components and to discuss their underlying pathobiological relationships.

Chronic intracranial recordings in the globus pallidus reveal circadian rhythms in Parkinson's disease

Circadian rhythms have been shown in the subthalamic nucleus (STN) in Parkinson's disease (PD), but only a few studies have focused on the globus pallidus internus (GPi). This retrospective study investigates GPi circadian rhythms in a large cohort of subjects with PD (130 recordings from 93 subjects) with GPi activity chronically recorded in their home environment. We found a significant change in GPi activity between daytime and nighttime in most subjects (82.4%), with a reduction in GPi activity at nighttime in 56.2% of recordings and an increase in activity in 26.2%. GPi activity in higher frequency bands ( > 20 Hz) was more likely to decrease at night and in patients taking extended-release levodopa medication. Our results suggest that circadian fluctuations in the GPi vary across individuals and that increased power at night might be due to the reemergence of pathological neural activity. These findings should be considered to ensure successful implementation of adaptive neurostimulation paradigms in the real-world.

Olfactory Epithelium Stimulation Using Rhythmic Nasal Air-Puffs Improves the Cognitive Performance of Individuals with Acute Sleep Deprivation

This study aimed to investigate the effects of intranasal air-puffing on cognitive impairments and brain cortical activity following one night of partial sleep deprivation (PSD) in adults. A total of 26 healthy adults underwent the numerical Stroop test (NST) and electroencephalography (EEG) before and after one night of PSD. Following PSD, subjects in the treatment group (n = 13) received nasal air-puffs (5 Hz, 3 min) before beginning the NST and EEG recording. Administration of nasal air-puffs in the treatment group restored the PSD-induced increase in error rate and decrease in reaction time and missing rate in the NST. Intranasal air-puffs recovered the PSD-induced augmentation of delta and theta power and the reduction of beta and gamma power in the EEG, particularly in the frontal lobes. Intranasal air-puffing also almost reversed the PSD-induced decrease in EEG signal complexity. Furthermore, it had a restorative effect on PSD-induced alteration in intra-default mode network functional connectivity in the beta and gamma frequency bands. Rhythmic nasal air-puffing can mitigate acute PSD-induced impairments in cognitive functions. It exerts part of its ameliorating effect by restoring neuronal activity in cortical brain areas involved in cognitive processing.

Preoperative Attention/Memory Problem Affects the Quality of Life of Parkinson's Disease Patients after Deep Brain Stimulation: A Cohort Study

Objectives

The aim of this study was to investigate the impact of nonmotor symptoms (NMS) on the quality of life (QoL) outcome after subthalamic nucleus deep brain stimulation (STN-DBS) at the 1-year follow-up.

Methods

Ninety-three patients diagnosed with Parkinson's disease (PD), who underwent subthalamic nucleus deep brain stimulation (STN-DBS) between April 2020 and August 2021, were included in this study. Demographic information was gathered through a self-designed questionnaire. The severity of both motor and non-motor symptoms, along with the quality of life (QoL), was assessed using the Unified Parkinson's Disease Rating Scale-III (UPDRS-III), Nonmotor Symptoms Scale (NMSS), and 8-item Parkinson's Disease Questionnaire (PDQ-8), respectively.

Results

Significant differences were observed in the UPDRS-III score, NMSS summary index (SI), and subscores of six domains (sleep/fatigue, mood/cognition, perceptual problems/hallucinations, attention/memory, urinary, and sexual function) between the baseline and the 6- and 12-month follow-ups. The correlation analysis revealed positive correlations between the preoperative NMSS SI and subscores of seven domains (cardiovascular, sleep/fatigue, mood/cognition, perceptual problems/hallucinations, attention/memory, gastrointestinal, and urinary) and ΔPDQ-8. Moreover, the preoperative PDQ-8 SI (β = 0.869, P < 0.001) and the preoperative attention/memory subscore (β = -0.154, P = 0.026) were predictive of the postsurgery improvement in quality of life (QoL).

Conclusion

Deep brain stimulation (DBS) led to an improvement in the patients' nonmotor symptoms (NMS) at the 1-year follow-up, along with a correlation observed between NMS and the patients' quality of life (QoL). Notably, the severity of preoperative attention/memory problems emerged as the most significant predictor of NMS influencing the QoL outcome after STN-DBS at the 1-year follow-up.

Neurostimulation for Generalized Epilepsy: Should Therapy be Syndrome-specific?

Current applications of neurostimulation for generalized epilepsy use a one-target-fits-all approach that is agnostic to the specific epilepsy syndrome and seizure type being treated. The authors describe similarities and differences between the 2 "archetypes" of generalized epilepsy-Lennox-Gastaut syndrome and Idiopathic Generalized Epilepsy-and review recent neuroimaging evidence for syndrome-specific brain networks underlying seizures. Implications for stimulation targeting and programming are discussed using 5 clinical questions: What epilepsy syndrome does the patient have? What brain networks are involved? What is the optimal stimulation target? What is the optimal stimulation paradigm? What is the plan for adjusting stimulation over time?

Exploring the network effects of deep brain stimulation for rapid eye movement sleep behavior disorder in Parkinson's disease

BACKGROUND

The research findings on the effects of subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson's disease (PD) with Rapid Eye Movement Sleep Behavior Disorder (RBD) are inconsistent, and there is a lack of research on DBS electrode sites and their network effects for the explanation of the differences. Our objective is to explore the optimal stimulation sites (that is the sweet spot) and the brain network effects of STN-DBS for RBD in PD.

METHODS

In this study, among the 50 PD patients who underwent STN-DBS treatment, 24 PD patients with RBD were screened. According to clinical scores and imaging data, the sweet spot of STN-DBS was analyzed in PD patients with RBD, and the optimal structure and functional network models of subthalamic stimulation were constructed.

RESULTS

Bilateral STN-DBS can effectively improve the symptoms of RBD and other non-motor symptoms in 24 PD patients with RBD. RBD Questionnaire-Hong Kong (RBDQ-HK) score was 41.33 ± 17.45 at baseline and 30.83 ± 15.83 at 1-year follow-up, with statistical significance between them (P < 0.01). However, the MoCA score was an exception with a baseline of 22.04 ± 4.28 and a 1-year follow-up of 21.58 ± 4.33, showing no statistical significance (P = 0.12). The sweet spot and optimal network connectivity models for RBD improvement have been validated as effective.

CONCLUSIONS

Bilateral STN-DBS can improve the symptoms of RBD in PD. There exist the sweet spot and brain network effects of bilateral STN-DBS in the treatment of PD with RBD. Our study also demonstrates that RBD is a brain network disease.

Impact of deep brain stimulation (DBS) on olfaction in Parkinson's disease: Clinical features and functional hypotheses

Deep brain stimulation (DBS) is a surgical therapy typically applied in Parkinson's disease (PD). The efficacity of DBS on the control of motor symptoms in PD is well grounded while the efficacity on non-motor symptoms is more controversial, especially on olfactory disorders (ODs). The present review shows that DBS does not improve hyposmia but can affect positively identification/discrimination scores in PD. The functional hypotheses suggest complex mechanisms in terms of cerebral connectivity and neurogenesis process which could act indirectly on the olfactory bulb and olfactory pathways related to specific cognitive olfactory tasks. The functional hypotheses also suggest complex mechanisms of cholinergic neurotransmitter interactions involved in these pathways. Finally, the impact of DBS on general cognitive functions in PD could also be beneficial to identification/discrimination tasks in PD.

A common neuronal ensemble in nucleus accumbens regulates pain-like behaviour and sleep

A comorbidity of chronic pain is sleep disturbance. Here, we identify a dual-functional ensemble that regulates both pain-like behaviour induced by chronic constrictive injury or complete Freund's adjuvant, and sleep wakefulness, in the nucleus accumbens (NAc) in mice. Specifically, a select population of NAc neurons exhibits increased activity either upon nociceptive stimulation or during wakefulness. Experimental activation of the ensemble neurons exacerbates pain-like (nociceptive) responses and reduces NREM sleep, while inactivation of these neurons produces the opposite effects. Furthermore, NAc ensemble primarily consists of D1 neurons and projects divergently to the ventral tegmental area (VTA) and preoptic area (POA). Silencing an ensemble innervating VTA neurons selectively increases nociceptive responses without affecting sleep, whereas inhibiting ensemble-innervating POA neurons decreases NREM sleep without affecting nociception. These results suggest a common NAc ensemble that encodes chronic pain and controls sleep, and achieves the modality specificity through its divergent downstream circuit targets.

Non-motor effects of deep brain stimulation in Parkinson's disease motor subtypes

INTRODUCTION

Deep brain stimulation (DBS) is a well-established treatment for patients with Parkinson's disease (PD) improving quality of life, motor, and non-motor symptoms. However, non-motor effects in PD subtypes are understudied. We hypothesized that patients with 'postural instability and gait difficulty' (PIGD) experience more beneficial non-motor effects than 'tremor-dominant' patients undergoing DBS for PD.

METHODS

In this prospective, observational, international multicentre study with a 6-month follow-up, we assessed the Non-Motor Symptom Scale (NMSS) as primary and the following secondary outcomes: Unified PD Rating Scale-motor examination (UPDRS-III), Scales for Outcomes in PD (SCOPA)-activities of daily living (ADL) and -motor complications, PDQuestionnaire-8 (PDQ-8), and levodopa-equivalent daily dose (LEDD). We analysed within-group longitudinal changes with Wilcoxon signed-rank test and Benjamini-Hochberg correction for multiple comparisons. Additionally, we explored outcome between-group differences of motor subtypes with Mann-Whitney U-tests.

RESULTS

In 82 PIGD and 33 tremor-dominant patients included in this study, baseline NMSS total scores were worse in PIGD patients, both groups experienced postoperative improvements of the NMSS sleep/fatigue domain, and between-group differences in postoperative outcomes were favourable in the PIGD group for the NMSS total and miscellaneous domain scores.

CONCLUSIONS

This study provides evidence of a favourable outcome of total non-motor burden in PIGD compared to tremor-dominant patients undergoing DBS for PD. These differences of clinical efficacy on non-motor aspects should be considered when advising and monitoring patients with PD undergoing DBS.

Parkinsonian daytime sleep-wake classification using deep brain stimulation lead recordings

Excessive daytime sleepiness is a recognized non-motor symptom that adversely impacts the quality of life of people with Parkinson's disease (PD), yet effective treatment options remain limited. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for PD motor signs. Reliable daytime sleep-wake classification using local field potentials (LFPs) recorded from DBS leads implanted in STN can inform the development of closed-loop DBS approaches for prompt detection and disruption of sleep-related neural oscillations. We performed STN DBS lead recordings in three nonhuman primates rendered parkinsonian by administrating neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Reference sleep-wake states were determined on a second-by-second basis by video monitoring of eyes (eyes-open, wake and eyes-closed, sleep). The spectral power in delta (1-4 Hz), theta (4-8 Hz), low-beta (8-20 Hz), high-beta (20-35 Hz), gamma (35-90 Hz), and high-frequency (200-400 Hz) bands were extracted from each wake and sleep epochs for training (70% data) and testing (30% data) a support vector machines classifier for each subject independently. The spectral features yielded reasonable daytime sleep-wake classification (sensitivity: 90.68 ± 1.28; specificity: 88.16 ± 1.08; accuracy: 89.42 ± 0.68; positive predictive value; 88.70 ± 0.89, n = 3). Our findings support the plausibility of monitoring daytime sleep-wake states using DBS lead recordings. These results could have future clinical implications in informing the development of closed-loop DBS approaches for automatic detection and disruption of sleep-related neural oscillations in people with PD to promote wakefulness.

Effects of subthalamic deep brain stimulation on non-motor symptoms of Parkinson's disease: A meta-analysis

Deep brain stimulation (DBS) is a well-defined treatment for motor symptoms in advanced PD. Although several studies have investigated the DBS effect on non-motor symptoms (NMS), controversial results exist regarding this matter. The aim of this meta-analysis and systematic review was to assess the bilateral subthalamic nucleus (STN) DBS effect on NMS of PD. We conducted a systematic search on the literature of Web of Science (WOS), PubMed/MEDLINE, Scopus, Cochrane, and Embase. An additional hand search was also done. Finally, a meta-analysis was conducted on 10 studies containing pre- and post-bilateral STN-DBS data regarding NMS acquired using Non-Motor Symptoms Scale for Parkinson's Disease (NMSS) or Non-Motor Symptoms Questionnaire (NMSQ). A random-effects model was used to determine weighted mean differences, and the heterogeneity index was evaluated using Cochrane's Q test. Our study results indicated that bilateral STN-DBS significantly reduced total NMSS and NMSQ score (WMD -17.73; 95% confidence interval [CI] -20.28 to -15.18, WMD -2.19; 95% CI -2.98 to -1.40), respectively, and no publication bias was found. Regarding each of the NMSS domains, DBS significantly reduced the scores of following domains: sleep (WMD -5.98; 95% CI -6.82 to -5.15), miscellaneous (WMD -4.19; 95% CI -4.96 to -3.43), urinary (WMD -2.99; 95% CI -3.78 to -2.19), sexual (WMD -0.65; 95% CI -1.16 to -0.14), and attention/memory (WMD -0.59; 95% CI -1.15 to -0.03). This meta-analysis demonstrated that bilateral STN-DBS has beneficial effects on NMS of PD.

Troubleshooting Gait Disturbances in Parkinson's Disease With Deep Brain Stimulation

Deep brain stimulation (DBS) of the subthalamic nucleus or the globus pallidus is an established treatment for Parkinson's disease (PD) that yields a marked and lasting improvement of motor symptoms. Yet, DBS benefit on gait disturbances in PD is still debated and can be a source of dissatisfaction and poor quality of life. Gait disturbances in PD encompass a variety of clinical manifestations and rely on different pathophysiological bases. While gait disturbances arising years after DBS surgery can be related to disease progression, early impairment of gait may be secondary to treatable causes and benefits from DBS reprogramming. In this review, we tackle the issue of gait disturbances in PD patients with DBS by discussing their neurophysiological basis, providing a detailed clinical characterization, and proposing a pragmatic programming approach to support their management.

Translational Approaches to Influence Sleep and Arousal

Sleep disorders are widespread in society and are prevalent in military personnel and in Veterans. Disturbances of sleep and arousal mechanisms are common in neuropsychiatric disorders such as schizophrenia, post-traumatic stress disorder, anxiety and affective disorders, traumatic brain injury, dementia, and substance use disorders. Sleep disturbances exacerbate suicidal ideation, a major concern for Veterans and in the general population. These disturbances impair quality of life, affect interpersonal relationships, reduce work productivity, exacerbate clinical features of other disorders, and impair recovery. Thus, approaches to improve sleep and modulate arousal are needed. Basic science research on the brain circuitry controlling sleep and arousal led to the recent approval of new drugs targeting the orexin/hypocretin and histamine systems, complementing existing drugs which affect GABA_A receptors and monoaminergic systems. Non-invasive brain stimulation techniques to modulate sleep and arousal are safe and show potential but require further development to be widely applicable. Invasive viral vector and deep brain stimulation approaches are also in their infancy but may be used to modulate sleep and arousal in severe neurological and psychiatric conditions. Behavioral, pharmacological, non-invasive brain stimulation and cell-specific invasive approaches covered here suggest the potential to selectively influence arousal, sleep initiation, sleep maintenance or sleep-stage specific phenomena such as sleep spindles or slow wave activity. These manipulations can positively impact the treatment of a wide range of neurological and psychiatric disorders by promoting the restorative effects of sleep on memory consolidation, clearance of toxic metabolites, metabolism, and immune function and by decreasing hyperarousal.

The efficacy of non-invasive, non-convulsive electrical neuromodulation on depression, anxiety and sleep disturbance: a systematic review and meta-analysis

The effects of non-invasive, non-convulsive electrical neuromodulation (NINCEN) on depression, anxiety and sleep disturbance are inconsistent in different studies. Previous meta-analyses on transcranial direct current stimulation (tDCS) and cerebral electrotherapy stimulation (CES) suggested that these methods are effective on depression. However, not all types of NINECN were included; results on anxiety and sleep disturbance were lacking and the influence of different populations and treatment parameters was not completely analyzed. We searched PubMed, Embase, PsycInfo, PsycArticles and CINAHL before March 2021 and included published randomized clinical trials of all types of NINCEN for symptoms of depression, anxiety and sleep in clinical and non-clinical populations. Data were pooled using a random-effects model. The main outcome was change in the severity of depressive symptoms after NINCEN treatment. A total of 58 studies on NINCEN were included in the meta-analysis. Active tDCS showed a significant effect on depressive symptoms (Hedges' g = 0.544), anxiety (Hedges' g = 0.667) and response rate (odds ratio = 1.9594) compared to sham control. CES also had a significant effect on depression (Hedges' g = 0.654) and anxiety (Hedges' g = 0.711). For all types of NINCEN, active stimulation was significantly effective on depression, anxiety, sleep efficiency, sleep latency, total sleep time, etc. Our results showed that tDCS has significant effects on both depression and anxiety and that these effects are robust for different populations and treatment parameters. The rational expectation of the tDCS effect is 'response' rather than 'remission'. CES also is effective for depression and anxiety, especially in patients with disorders of low severity.

The subthalamic corticotropin-releasing hormone neurons mediate adaptive REM-sleep responses to threat

When an animal faces a threatening situation while asleep, rapid arousal is the essential prerequisite for an adequate response. Here, we find that predator stimuli induce immediate arousal from REM sleep compared with NREM sleep. Using in vivo neural activity recording and cell-type-specific manipulations, we identify neurons in the medial subthalamic nucleus (mSTN) expressing corticotropin-releasing hormone (CRH) that mediate arousal and defensive responses to acute predator threats received through multiple sensory modalities across REM sleep and wakefulness. We observe involvement of the same neurons in the normal regulation of REM sleep and the adaptive increase in REM sleep induced by sustained predator stress. Projections to the lateral globus pallidus (LGP) are the effector pathway for the threat-coping responses and REM-sleep expression. Together, our findings suggest adaptive REM-sleep responses could be protective against threats and uncover a critical component of the neural circuitry at their basis.

Autonomic Dysfunction in Sleep Disorders: From Neurobiological Basis to Potential Therapeutic Approaches

Sleep disorder has been portrayed as merely a common dissatisfaction with sleep quality and quantity. However, sleep disorder is actually a medical condition characterized by inconsistent sleep patterns that interfere with emotional dynamics, cognitive functioning, and even physical performance. This is consistent with sleep abnormalities being more common in patients with autonomic dysfunction than in the general population. The autonomic nervous system coordinates various visceral functions ranging from respiration to neuroendocrine secretion in order to maintain homeostasis of the body. Because the cell population and efferent signals involved in autonomic regulation are spatially adjacent to those that regulate the sleep-wake system, sleep architecture and autonomic coordination exert effects on each other, suggesting the presence of a bidirectional relationship in addition to shared pathology. The primary goal of this review is to highlight the bidirectional and shared relationship between sleep and autonomic regulation. It also introduces the effects of autonomic dysfunction on insomnia, breathing disorders, central disorders of hypersomnolence, parasomnias, and movement disorders. This information will assist clinicians in determining how neuromodulation can have the greatest therapeutic effects in patients with sleep disorders.

Basal Ganglia Local Field Potentials as a Potential Biomarker for Sleep Disturbance in Parkinson's Disease

Sleep disturbances, specifically decreases in total sleep time and sleep efficiency as well as increased sleep onset latency and wakefulness after sleep onset, are highly prevalent in patients with Parkinson's disease (PD). Impairment of sleep significantly and adversely impacts several comorbidities in this patient population, including cognition, mood, and quality of life. Sleep disturbances and other non-motor symptoms of PD have come to the fore as the effectiveness of advanced therapies such as deep brain stimulation (DBS) optimally manage the motor symptoms. Although some studies have suggested that DBS provides benefit for sleep disturbances in PD, the mechanisms by which this might occur, as well as the optimal stimulation parameters for treating sleep dysfunction, remain unknown. In patients treated with DBS, electrophysiologic recording from the stimulating electrode, in the form of local field potentials (LFPs), has led to the identification of several findings associated with both motor and non-motor symptoms including sleep. For example, beta frequency (13–30 Hz) oscillations are associated with worsened bradykinesia while awake and decrease during non-rapid eye movement sleep. LFP investigation of sleep has largely focused on the subthalamic nucleus (STN), though corresponding oscillatory activity has been found in the globus pallidus internus (GPi) and thalamus as well. LFPs are increasingly being recognized as a potential biomarker for sleep states in PD, which may allow for closed-loop optimization of DBS parameters to treat sleep disturbances in this population. In this review, we discuss the relationship between LFP oscillations in STN and the sleep architecture of PD patients, current trends in utilizing DBS to treat sleep disturbance, and future directions for research. In particular, we highlight the capability of novel technologies to capture and record LFP data in vivo, while patients continue therapeutic stimulation for motor symptoms. These technological advances may soon allow for real-time adaptive stimulation to treat sleep disturbances.

DBS-Edmonton App, a Tool to Manage Patient Expectations of DBS in Parkinson Disease

Objective

After deep brain stimulation (DBS) for Parkinson disease (PD), patients often do not report the level of satisfaction anticipated. This misalignment can relate to patients' expectations for an invasive treatment and insufficient knowledge of DBS's effectiveness in relieving motor and nonmotor symptoms (NMS). Patient satisfaction depends on expectations and goals for treatment. We hypothesized that improving patient education with a patient-centered shared decision-making tool emphasizing autonomy would improve patient satisfaction and clinical outcome.

Methods

We developed a computer application (DBS-Edmonton app), allowing patients with PD to input their symptoms and to learn how effective DBS addresses their prioritized symptoms. Sixty-two volunteers referred for DBS used the DBS-Edmonton app. DBS-related knowledge and patient perceptions of the DBS-Edmonton app were assessed with pre- and post-use questionnaires. Fourteen of 24 patients who proceeded to DBS achieved optimization at 6 months. Perceived functional improvement was assessed and compared with 12 control patients with DBS who did not use the DBS-Edmonton app.

Results

All 62 volunteers considered the DBS-Edmonton app helpful and would recommend it to others. There was improved knowledge about how NMS and axial symptoms respond to DBS. Postoperatively, there was no significant difference in symptoms improvement assessed by standard scales between the groups. Volunteers who used the DBS-Edmonton app had greater satisfaction (p = 0.014).

Conclusion

This interventional study showed that the DBS-Edmonton app improved DBS-related knowledge and patient satisfaction, independent of the objective motor outcome. It may assist patients in deciding to proceed to DBS and can be easily incorporated into practice to improve patient satisfaction post-DBS.

The Neurophysiology of Sleep in Parkinson's Disease

Sleep disturbances are among the most common nonmotor complications of Parkinson's disease (PD), can present in prodromal stages, and progress with advancing disease. In addition to being a symptom of neurodegeneration, sleep disturbances may also contribute to disease progression. Currently, limited options exist to modulate sleep disturbances in PD. Studying the neurophysiological changes that affect sleep in PD at the cortical and subcortical level may yield new insights into mechanisms for reversal of sleep disruption. In this article, we review cortical and subcortical recording studies of sleep in PD with a particular focus on dissecting reported electrophysiological changes. These studies show that slow-wave sleep and rapid eye movement sleep are both notably disrupted in PD. We further explore the impact of these electrophysiological changes and discuss the potential for targeting sleep via stimulation therapy to modify PD-related motor and nonmotor symptoms. © 2021 International Parkinson and Movement Disorder Society.

Intrajejunal Infusion of Levodopa/Carbidopa for Advanced Parkinson's Disease: A Systematic Review

Advanced Parkinson's disease is inconsistently defined, and evidence is lacking in relation to device‐aided therapies. To update existing reviews of intrajejunal infusion of levodopa/carbidopa (LCIG), we performed a literature search for relevant articles (to November 3, 2020) using PubMed supplemented by hand searching. Retrieved articles were categorized by relevance to identified research questions, including motor complications and symptoms; nonmotor symptoms; functioning, quality of life, and caregiver burden; optimal timing of treatment initiation and administration duration; discontinuation; and complications. Most eligible studies (n = 56) were open‐label, observational studies including relatively small patient numbers. LCIG consistently reduces OFF time and increased ON time without troublesome dyskinesia with varying effects regarding ON time with troublesome dyskinesia and the possibility of diphasic dyskinesia. More recent evidence provides some increased support for the benefits of LCIG in relation to nonmotor symptoms, quality of life, activities of daily living, and reduced caregiver burden. Patient age does not appear to significantly impact the effectiveness of LCIG. Discontinuation rates with LCIG (~17%–26%) commonly relate to device‐related issues, although the ability to easily discontinue LCIG may represent a potential benefit. LCIG may be a favorable option for patients with advanced Parkinson's disease who show predominant nonmotor symptoms and vulnerability to complications of other advanced therapy modalities. Larger, well‐controlled studies, including precise investigation of cost effectiveness, would further assist treatment selection. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

Subthalamic deep brain stimulation improves sleep and excessive sweating in Parkinson’s disease

Parkinson’s disease (PD) is a complex multisystem disorder with motor and non-motor symptoms (NMS). NMS may have an even greater impact on quality of life than motor symptoms. Subthalamic nucleus deep brain stimulation (STN-DBS) has been shown to improve motor fluctuations and quality of life, whereas the effects on different NMS have been less examined. Sleep disturbances and autonomic dysfunction are among the most prevalent NMS. We here report the efficacy of STN-DBS on sleep disturbances and autonomic dysfunction. In the parent trial, 60 patients were included in a single-center randomized prospective study, with MDS-UPDRS III and PDQ-39 as primary endpoints at 12 months of STN-DBS. Preplanned assessments at baseline and postoperatively at 3 and 12 months also included Parkinson’s Disease Sleep Scale (PDSS); Scopa-Aut; and MDS-UPDRS I, II, and IV. We found that STN-DBS had a significant and lasting positive effect on overall sleep quality, nocturnal motor symptoms and restlessness, and daytime dozing. Several aspects of autonomic dysfunction were also improved at 3 months postoperatively, although at 12 months only thermoregulation (sudomotor symptoms) remained significantly improved. We could not identify preoperative factors that predicted improvement in PDSS or Scopa-Aut. There was a close relationship between improved autonomic symptoms and improved quality of life after 1 year. NMS and especially sleep and autonomic dysfunction deserve more focus to improve patient outcomes further.

A quantitative analysis of the effect of bilateral subthalamic nucleus-deep brain stimulation on subjective and objective sleep parameters in Parkinson's disease

OBJECTIVE

To explore how subjective and objective sleep parameters respond to bilateral subthalamic nucleus-deep brain stimulation (STN-DBS) in patients with Parkinson's disease (PD).

METHODS

Thirty DBS sleep studies were included by searching PubMed, Embase, and the Cochrane Library, and only 21 prospectively designed studies, including 541 patients, were eligible for the main analysis. We evaluated sleep disturbance using 1 objective measurement, polysomnography (PSG), and 4 subjective scales, including PD Sleep Scale (PDSS), Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and restless legs syndrome (RLS). We pooled data using the standard mean difference (SMD). The primary outcome was a change in sleep parameters 6 months postoperatively. Outcomes from <12 months to ≥12 months follow-up were compared in the subgroup analysis. Meta-regression was further conducted.

RESULTS

STN-DBS significantly improved all 4 subjective sleep scales in the 6-month follow-up: ESS (SMD = 0.234), PDSS (SMD = 0.724), PSQI (SMD = 1.374) and RLS (SMD = 1.086), while most PSG parameters remained unchanged, except for shortened rapid eye movement sleep latency (RSL) (SMD = 0.520). In the over-12-month follow-up, improvement persisted in PDSS but not in ESS. Dopamine drug reduction (p = 0.009) and motor improvement (p = 0.036) were correlated with ESS improvement and PDSS improvement, respectively.

CONCLUSIONS

Bilateral STN-DBS continuously improved subjective nocturnal sleep, while its effect on ESS lasted for only 1 year. Medication reduction and motor improvement may contribute to improved daytime sleepiness and better subjective nocturnal sleep, respectively. Except for a shortened RSL, STN-DBS did not change PSG parameters, including sleep efficiency and sleep architecture.

REGISTRATION

Open Science Framework: DOI 10.17605/OSF.IO/3EGRC.

Sleep Issues in Parkinson's Disease and Their Management

Parkinson's disease (PD) is an alpha-synucleinopathy that leads to prominent motor symptoms including tremor, bradykinesia, and postural instability. Nonmotor symptoms including autonomic, neurocognitive, psychiatric symptoms, and sleep disturbances are also seen frequently in PD. The impact of PD on sleep is related to motor and nonmotor symptoms, in addition to the disruption of the pathways regulating sleep by central nervous system pathology. Rapid eye movement sleep behavior disorder is a parasomnia that can lead to self-injury and/or injury to partners at night. Restless legs syndrome is a subjective sensation of discomfort and urge to move the legs prior to falling asleep and can lead to insomnia and reduced sleep quality. Excessive daytime sleepiness is common in PD and exerts a negative impact on quality of life in addition to increasing the risk of falls. Obstructive sleep apnea is a breathing disorder during sleep that can cause frequent awakenings and excessive daytime sleepiness. Circadian rhythm dysfunction can lead to an advanced or delayed onset of sleep in patients and create disruption of normal sleep and wake times. All of these disorders are common in PD and can significantly reduce sleep quantity, sleep quality, or quality of life for patients and caretakers. Treatment approaches for each of these disorders are distinct and should be individualized to the patient. We review the literature regarding these common sleep issues encountered in PD and their treatment options.

Deep brain stimulation reduces (nocturnal) dyskinetic exacerbations in patients with ADCY5 mutation: a case series

Mutations in the ADCY5 gene can cause a complex hyperkinetic movement disorder. Episodic exacerbations of dyskinesia are a particularly disturbing symptom as they occur predominantly during night and interrupt sleep. We present the clinical short- and long-term effects of pallidal deep brain stimulation (DBS) in three patients with a confirmed pathogenic ADCY5 mutation. Patients were implanted with bilateral pallidal DBS at the age of 34, 20 and 13 years. Medical records were reviewed for clinical history. Pre- and postoperative video files were assessed using the “Abnormal Involuntary Movement Scale” (AIMS) as well as the motor part of the “Burke Fahn Marsden Dystonia Rating Scale” (BFMDRS). All patients reported subjective general improvement ranging from 40 to 60%, especially the reduction of nocturnal episodic dyskinesias (80–90%). Objective scales revealed only a mild decrease of involuntary movements in all and reduced dystonia in one patient. DBS-induced effects were sustained up to 13 years after implantation. We demonstrate that treatment with pallidal DBS was effective in reducing nocturnal dyskinetic exacerbations in patients with ADCY5-related movement disorder, which was sustained over the long term.

Subthalamic Nucleus Deep Brain Stimulation in Primary Meige Syndrome: A 1-Year Follow-Up Study

OBJECTIVE

To investigate the efficacy of bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with Meige syndrome.

MATERIALS AND METHODS

Fifteen consecutive patients who underwent STN-DBS at the Peking University People's Hospital between September 2017 and June 2018 were included in this study. The Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) movement score and the BFMDRS disability score were obtained prior to surgery, and at specific time points after surgery. Patients' sleep status was also assessed before and after surgery.

RESULTS

The BFMDRS movement scores decreased from 15.3 ± 4.6 to 5.2 ± 6.2 after STN-DBS, with a mean improvement of 68.6% (p < 0.05). The BFMDRS disability scores were also significantly decreased, from 6.9 ± 3.3 to 3.5 ± 2.9, with a mean improvement of 51.7% (p < 0.05). The eye, mouth, speech, and swallowing movement scores also decreased significantly after STN-DBS compared to baseline (p < 0.05). The sleep quality of the patients was also improved after surgery.

CONCLUSIONS

These findings demonstrate that the STN is an effective brain target for the treatment of patients with Meige syndrome. STN-DBS was not only able to improve patients' motor symptoms, but also their sleep status.

Effect of acupuncture and its influence on cerebral activity in patients with persistent asthma: study protocol for a randomized controlled clinical trial

Background

Previous studies suggested that acupuncture was a promising adjunctive treatment for asthma. However, the underlying mechanism of acupuncture for asthma remains unclear. The aim of the present trial is to explore whether and how specific meridian acupuncture works in quality of life and symptomatic improvement by modulating brain function in patients with asthma.

Methods/design

This is a randomized controlled functional brain imaging trial currently being conducted in Sichuan, China. In total, 48 patients with mild to moderate persistent asthma will be recruited randomly and allocated to either of two acupuncture groups: acupuncture at the lung meridian or acupuncture at the heart meridian. The treatment period will last 4 weeks. The Asthma Quality of Life Questionnaire is the primary outcome. The Asthma Control Test, peak expiratory flow rate, forced expiratory volume in 1 s, Montreal Cognitive Assessment, Zung Self-rating Anxiety Scale, and Zung Self-rating Depression Scale will also be used to assess the clinical efficacy of different interventions. Functional magnetic resonance imaging (fMRI) will be performed to detect cerebral activity changes in each group. The clinical data and fMRI data will be analyzed between groups, then, the Pearson correlation analysis will be used to assess the association between the changes of cerebral activity features and the improvement of clinical outcomes in each group.

Discussion

The present study has been established on the basis of the “meridian–viscera relationship” theory of traditional Chinese medicine and the modern central mechanism of acupuncture. The results of this trial would be useful to identify the efficiency of the specific meridian acupuncture for asthma. The investigation of its central mechanism would further expand knowledge of acupuncture for asthma.

Trial registration

Chinese Clinical Trial Registry, ChiCTR1900027478. Registered on 15 November 2019.

Kinematic gait parameters for older adults with Parkinson's disease during street crossing simulation

Safe street crossing is important for older adults' social inclusion. We assessed gait kinematic adaptation under different simulated street crossing conditions in older adults with Parkinson's disease (PD) and made comparisons with older adults without PD to understand how PD interferes in outdoor task performance, helping in the development of strategies to reduce road traffic accident risk. In 20 older adults without PD (control group - CG) and 20 with PD (GPD), we assessed usual gait (C1), gait during street crossing simulation (C2), and gait during reduced-time street crossing simulation (C3). Velocity, step length, and step, swing, stance, and double support time were analyzed. Spatiotemporal differences in gait between groups and conditions were analyzed. The GPD walked 16% slower in C1 and 12% slower in C2 and C3 than the CG. GPD also took 11% shorter steps in C1 and 9.5% shorter steps in C2. The double support time was 8.5% greater in C1. In intragroup comparisons, there were significant differences in all gait conditions. The CG showed increased velocity (C2 15% > C1; C3 13% > C2; C3 26% > C1), step length (C2 8% > C1; C3 5% > C2; C3 13% > C1), and swing time (C2 2% > C1; C3 3.7% > C2; C3 6% > C1), and decreased step time (C2 7.5% < C1; C3 8% < C2; C3 15% < C1), stance time (C2 1.3% < C1; C3 2.5% < C2; C3 3.6% < C1), and double support time (C2 6.3% < C1; C3 10.5% < C2; C3 16% < C1). GPD showed increased velocity (C2 19% > C1; C3 13.5% > C2; C3 29.7% > C1), step length, (C2 6% > C1; C3 7% > C2; C3 16% > C1), and swing time (C2 3% > C1; C3 3% > C2; C3 5.5% > C1) and decreased step time (C2 10.3% < C1; C3 7.7% < C2; C3 17% < C1), stance time (C2 1.7% < C1; C3 1.7% < C2; C3 3.4% < C1), and double support time (C2 7% < C1; C3 9.5% < C2; C3 16% < C1). Kinematic changes observed in the intergroup comparison show that participants with PD had lower velocity in all conditions. However, per the intragroup results, both participants with and without PD managed to significantly modify gait variables to attempt to cross the street in the given time. It is necessary to assess whether this increases fall risk by exposing them to road traffic accidents.

Practical Evaluation and Management of Insomnia in Parkinson's Disease: A Review

Background

Insomnia is one of the most common nonmotor features of Parkinson's disease (PD). However, there are few practical guidelines for providers on how to best evaluate and treat this problem.

Methods and Findings

This review was developed to provide clinicians with a pragmatic approach to assessing and managing insomnia in PD. Recommendations were based on literature review and expert opinion. We addressed the following topics in this review: prevalence of insomnia in PD, sleep-wake mechanisms, theoretical models of insomnia, risk factors, assessment, pharmacologic and nonpharmacologic treatments. Insomnia treatment choices may be guided by PD severity, comorbidities, and patient preference. However, there is limited evidence supporting pharmacotherapy and nonpharmacologic treatments of insomnia in PD.

Conclusions

We provide a pragmatic algorithm for evaluating and treating insomnia in PD based on the literature and our clinical experience. We propose personalized insomnia treatment approaches based on age and other issues. Gaps in the existing literature and future directions in the treatment of insomnia in PD are also highlighted.

Emerging technologies for improved deep brain stimulation

Deep brain stimulation (DBS) is an effective treatment for common movement disorders and has been used to modulate neural activity through delivery of electrical stimulation to key brain structures. The long-term efficacy of stimulation in treating disorders, such as Parkinson's disease and essential tremor, has encouraged its application to a wide range of neurological and psychiatric conditions. Nevertheless, adoption of DBS remains limited, even in Parkinson's disease. Recent failed clinical trials of DBS in major depression, and modest treatment outcomes in dementia and epilepsy, are spurring further development. These improvements focus on interaction with disease circuits through complementary, spatially and temporally specific approaches. Spatial specificity is promoted by the use of segmented electrodes and field steering, and temporal specificity involves the delivery of patterned stimulation, mostly controlled through disease-related feedback. Underpinning these developments are new insights into brain structure-function relationships and aberrant circuit dynamics, including new methods with which to assess and refine the clinical effects of stimulation.

The impact of subthalamic deep brain stimulation on sleep and other non-motor symptoms in Parkinson's disease

INTRODUCTION

The non-motor symptoms have a major impact on quality of life in patients with Parkinson Disease (PD). We present results of the study on the impact of subthalamic deep brain stimulation (DBS-STN) on sleep and other non-motor symptoms in PD patients.

MATERIALS AND METHODS

Thirty-six patients with advanced PD were included into the study. Twenty four were evaluated with two-night polysomnography (PSG) before surgery and at 6 months after DBS programming. The whole group (n = 36) was assessed using motor, non-motor symptoms (sleep disturbances in particular) and quality of life measures (QoL), before surgery, 6 and 12 months after DBS programming.

RESULTS

DBS-STN resulted in the significant deterioration of objective sleep parameters, as assessed by PSG, mostly in terms of total sleep time, sleep efficiency, duration of N1 and N2 sleep, wakefulness after sleep onset and sleep latency. At the same time, improvement in the subjective sleep measures, other non-motor symptoms (particularly fatigue, cardiovascular, gastrointestinal, and sexual symptoms) and QoL was identified. The subjective improvement of sleep, other non-motor symptoms and QoL was most prominent in the first 6 months after DBS-STN, diminished slightly (being still better than before surgery) after 12 months, in parallel to mood deterioration.

CONCLUSION

DBS-STN resulted in the subjective sleep quality improvement with worsening of objective (PSG) sleep parameters after 6 months. After 12 months all sleep clinical outcome measures were still better than before surgery, albeit worse when compared to the first follow-up visit. Subjective sleep quality correlated positively with mood.

Back to the Basics: Resting State Functional Connectivity of the Reticular Activation System in PTSD and its Dissociative Subtype

BACKGROUND

Brainstem and midbrain neuronal circuits that control innate, reflexive responses and arousal are increasingly recognized as central to the neurobiological framework of post-traumatic stress disorder (PTSD). The reticular activation system represents a fundamental neuronal circuit that plays a critical role not only in generating arousal but also in coordinating innate, reflexive responding. Accordingly, the present investigation aims to characterize the resting state functional connectivity of the reticular activation system in PTSD and its dissociative subtype.

METHODS

We investigated patterns of resting state functional connectivity of a central node of the reticular activation system, namely, the pedunculopontine nuclei, among individuals with PTSD (n = 77), its dissociative subtype (PTSD+DS; n = 48), and healthy controls (n = 51).

RESULTS

Participants with PTSD and PTSD+DS were characterized by within-group pedunculopontine nuclei resting state functional connectivity to brain regions involved in innate threat processing and arousal modulation (i.e., midbrain, amygdala, ventromedial prefrontal cortex). Critically, this pattern was most pronounced in individuals with PTSD+DS, as compared to both control and PTSD groups. As compared to participants with PTSD and controls, individuals with PTSD+DS showed enhanced pedunculopontine nuclei resting state functional connectivity to the amygdala and the parahippocampal gyrus as well as to the anterior cingulate and the ventromedial prefrontal cortex. No group differences emerged between PTSD and control groups. In individuals with PTSD+DS, state derealization/depersonalization was associated with reduced resting state functional connectivity between the left pedunculopontine nuclei and the anterior nucleus of the thalamus. Altered connectivity in these regions may restrict the thalamo-cortical transmission necessary to integrate internal and external signals at a cortical level and underlie, in part, experiences of depersonalization and derealization.

CONCLUSIONS

The present findings extend the current neurobiological model of PTSD and provide emerging evidence for the need to incorporate brainstem structures, including the reticular activation system, into current conceptualizations of PTSD and its dissociative subtype.