The effect of unilateral subthalamic nucleus deep brain stimulation on depression in Parkinson's disease

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.

Premature drug reduction after subthalamic nucleus deep brain stimulation leading to worse depression in patients with Parkinson's disease

Background

Reduction of medication in Parkinson's disease (PD) following subthalamic nucleus deep brain stimulation (STN-DBS) has been recognized, but the optimal timing for medication adjustments remains unclear, posing challenges in postoperative patient management.

Objective

This study aimed to provide evidence for the timing of medication reduction post-DBS using propensity score matching (PSM).

Methods

In this study, initial programming and observation sessions were conducted over 1 week for patients 4-6 weeks postoperatively. Patients were subsequently categorized into medication reduction or non-reduction groups based on their dyskinesia evaluation using the 4.2-item score from the MDS-UPDRS-IV. PSM was employed to maintain baseline comparability. Short-term motor and neuropsychiatric symptom assessments for both groups were conducted 3-6 months postoperatively.

Results

A total of 123 PD patients were included. Baseline balance in motor and non-motor scores was achieved between the two groups based on PSM. Short-term efficacy revealed a significant reduction in depression scores within the non-reduction group compared to baseline (P < 0.001) and a significant reduction compared to the reduction group (P = 0.037). No significant differences were observed in UPDRS-III and HAMA scores between the two groups. Within-group analysis showed improvements in motor symptoms, depression, anxiety, and subdomains in the non-reduction group, while the reduction group exhibited improvements only in motor symptoms.

Conclusion

This study provides evidence for the timing of medication reduction following DBS. Our findings suggest that early maintenance of medication stability is more favorable for improving neuropsychiatric symptoms.

Effectiveness of deep brain stimulation in Parkinson's disease treatment with Single-center experience in Pakistan

Objective

To assess the effectiveness and accuracy of deep brain stimulation in Parkinsonian Disease (PD).

Methods

This study was a descriptive prospective study, and patients were treated at Neurospinal and Cancer Care Institute Karachi, from February 1, 2016, to June 30, 2020. We had 21 cases of parkinsonian disease. Inclusion criteria was Idiopathic Parkinson's disease, marked motor fluctuations against the response to dopaminergic therapy, UPDRS-III scores, which is 30 or higher, with a duration of disease of five years or longer, developing dyskinesia while the exclusion criteria was patient with known comorbid or active psychiatric disease.

Results

Mean age of patient was 64 years. The standard deviation was 1.11697. The male patients' mean, median and mode had a standard deviation of 0.3. For the duration of disease, the mean was 1.4, the median 1 (5-6 years) and mode one. The standard deviation was 0.51177. The primary symptoms' mean was 2.2857, the median was 2.0, and the mode was two (tremor). The mean on medication (age) was 2 (45-49), and the median and mode were the same.

Conclusion

Deep brain stimulation (DBS) is an effective treatment option for a carefully selected patient. DBS improves tremors, dyskinesias, rigidity, motor fluctuations and bradykinesia. DBS is unlikely to benefit Autonomic dysfunction, cognitive disorders, hypophonia, and postural instability. Although it is an expensive treatment compared to lesioning or gamma knife, it is reversible.

Advances in the Pharmacological and Non-pharmacological Management of Non-motor Symptoms in Parkinson's Disease: An Update Since 2017

BACKGROUND

Non-motor symptoms (NMS) are an important and ubiquitous determinant of quality of life in Parkinson's disease (PD). However, robust evidence for their treatment is still a major unmet need.

OBJECTIVE

This study aimed to provide an updated review on advances in pharmacological, nonpharmacological, and exercise-based interventions for NMS in PD, covering the period since the publication of the MDS Task Force Recommendations.

METHODS

We performed a literature search to identify pharmacological, non-pharmacological, and exercise-based interventions for NMS in PD. As there are recent reviews on the subject, we have only included studies from the 1st of January 2017 to the 1st of December 2021 and limited our search to randomised and non-randomised (including open-label) clinical trials.

RESULTS

We discuss new strategies to manage NMS based on data that have become available since 2017, for instance, on the treatment of orthostatic hypotension with droxidopa, several dopaminergic treatment options for insomnia, and a range of non-pharmacological and exercise-based interventions for cognitive and neuropsychiatric symptoms, pain, and insomnia and excessive sleepiness.

CONCLUSION

Recent evidence suggests that targeted non-pharmacological treatments, as well as some other NMS management options, may have a significant beneficial effect on the quality of life and need to be considered in the pathways of treatment of PD.

Effects of Subthalamic Nucleus Deep Brain Stimulation on Depression in Patients with Parkinson's Disease

Objective: In this study, we aimed to investigate the effects of STN-DBS on PD patients with different levels of depression and to identify predictors of the effects of STN-DBS on PD depression. Methods: We retrospectively collected data for 118 patients with PD depression who underwent STN-DBS at Beijing Tiantan Hospital. Neuropsychological, motor, and quality of life assessments were applied preoperatively and postoperatively. All patients were divided into two groups according to their HAM-D24 total scores (group I: mild depression; group Ⅱ: moderate depression). A mixed repeated-measure analysis of variance (ANOVA) was performed to investigate whether there were differences in depression scores before and after STN-DBS between the two groups. The changes in depression scores were also compared between groups using ANCOVA, adjusting for gender and preoperative HAMA scores. Logistic regression was performed to identify predictors of STN-DBS’s effects on PD depression. Results: Both groups showed significant improvement in depression symptoms after STN-DBS. Compared with patients in group I, patients in group Ⅱ showed greater reductions in their HAM-D24 total scores (p = 0.002) and in HAM-D24 subitems including cognitive disturbances (p = 0.026) and hopelessness symptoms (p = 0.018). Logistic regression indicated that gender (female) (p = 0.014) and preoperative moderate depression (p < 0.001) patients had greater improvements in depression after STN-DBS. Conclusions: Patients with moderate depression showed better improvement than patients with mild depression. Gender (female) and preoperative HAMA scores are predictors of STN-DBS’s effects on PD depression.

Correlation between Electrode Location and Anxiety Depression of Subthalamic Nucleus Deep Brain Stimulation in Parkinson's Disease

Objectives: our group explored the correlation between postoperative coordinates of the electrode contacts, VTA, and anxiety and depression symptoms in Parkinson’s disease (PD) patients after subthalamic nucleus deep brain stimulation (STN-DBS). Methods: STN-DBS was conducted on PD patients (n = 57) for six months with follow-up. Clinical outcomes were explored using the unified Parkinson’s disease rating scale Part III (UPDRS-III), the Hamilton Anxiety Rating Scale (HAM-A), and the Hamilton Depression Rating Scale (HAM-D) before and after surgery. At the Montreal Neurological Institute (MNI), the location of active contacts and the volume of tissue activated (VTA) were calculated. Results: patient evaluations took place preoperatively and follow-ups took place at 1 month, 3 months, and 6 months. The average patient improvement rates for HAM-A and HAM-D scores at the 6-month follow-up were 41.7% [interquartile range (IQR) 34.9%] and 37.5% (IQR 33.4%), respectively (both p < 0.001). In medication-off, there were negative correlations between the HAM-A improvement rate and the Z-axis coordinate of the active contact (left side: r = −0.308, p = 0.020; right side: r = −0.390, p = 0.003), and negative correlations between the HAM-D improvement rate and the Z-axis coordinate of the active contact (left side: r = −0.345, p = 0.009; right side: r = −0.521, p = 0.001). There were positive correlations between the HAM-A and HAM-D scores improvement rate at 6 months after surgery and bilateral VTA in the right STN limbic subregion (HAM-A: r = 0.314, p = 0.018; HAM-D: r = 0.321, p = 0.015). Conclusion: bilateral STN-DBS can improve anxiety and depression symptoms in PD patients. The closer the stimulation to the ventral limbic region of the STN, the more significant the improvement in anxiety and depression symptoms of PD patients.

Effects of Bilateral Subthalamic Nucleus Stimulation on Depressive Symptoms and Cerebral Glucose Metabolism in Parkinson's Disease: A 18F-Fluorodeoxyglucose Positron Emission Tomography/Computerized Tomography Study

Subthalamic nucleus (STN) deep brain stimulation (DBS) can improve motor symptoms in Parkinson's disease (PD), as well as potentially improving otherwise intractable comorbid depressive symptoms. To address the latter issue, we evaluated the severity of depressive symptoms along with the severity of motor symptoms in 18 PD patients (mean age, 58.4 ± 5.4 years; 9 males, 9 females; mean PD duration, 9.4 ± 4.4 years) with treatment-resistant depression (TRD) before and after approximately 1 year of STN-DBS treatment. Moreover, to gain more insight into the brain mechanism mediating the therapeutic action of STN-DBS, we utilized ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to assess cerebral regional glucose metabolism in the patients at baseline and 1-year follow-up. Additionally, the baseline PET data from patients were compared with PET data from an age- and sex-matched control group of 16 healthy volunteers. Among them, 12 PD patients underwent post-operative follow-up PET scans. Results showed that the severity of both motor and depressive symptoms in patients with PD-TRD was reduced significantly at 1-year follow-up. Also, patients used significantly less antiparkinsonian medications and antidepressants at 1-year follow-up, as well as experiencing improved daily functioning and a better quality of life. Moreover, relative to the PET data from healthy controls, PD-TRD patients displayed widespread abnormalities in cerebral regional glucose metabolism before STN-DBS treatment, which were partially recovered at 1-year follow-up. Additionally, significant correlations were observed between the patients' improvements in depressive symptoms following STN-DBS and post-operative changes in glucose metabolism in brain regions implicated in emotion regulation. These results support the view that STN-DBS provides a promising treatment option for managing both motor and depressive symptoms in patients who suffer from PD with TRD. However, the results should be interpreted with caution due to the observational nature of the study, small sample size, and relatively short follow-up.

Bilateral Subthalamic Nucleus Deep Brain Stimulation Improves Gastric Emptying Time in Parkinson Disease

BACKGROUND

It is well-established that deep brain stimulation (DBS) can improve motor function in those with Parkinson disease (PD); however, its effects on gastrointestinal disorders remain unclear.

METHODS

From January 2019 to December 2020, 26 patients with PD who had undergone subthalamic nucleus (STN) DBS were included in our study. The evaluated items included the pre- and postoperative dose of levodopa, Unified Parkinson's Disease Rating Scale, part III, scores with and without medication and stimulation, and gastric emptying time (expressed as the peak time of carbon-¹³C dioxide excretion in the ¹³C-acetate breath test). Sex-, age-, and body weight-matched controls were recruited to test the gastric emptying time in healthy individuals.

RESULTS

All the patients benefited from DBS. The Unified Parkinson's Disease Rating Scale, part III, scores had decreased from 48.5 ± 13.77 to 25.23 ± 8.59 without medication and 31.23 ± 11.4 to 13.92 ± 5.27 with medication. The levodopa equivalent dose had decreased from 1009.8 ± 291 mg to 707.65 ± 193.79 mg. The gastric emptying time was significantly prolonged in the patients with PD before DBS compared with the healthy control group (29.23 ± 6.58 minutes) and had improved to 35.19 ± 10.14 minutes with medication and 38.07 ± 11.17 minutes without medication after 3 months of STN stimulation. At 6 months postoperatively, the gastric emptying time was 32.3 ± 10.02 minutes without medication and 33.84 ± 10.79 minutes with medication.

CONCLUSIONS

A delayed gastric emptying time is associated with greater PD severity. Antiparkinsonian medications did not affect gastric emptying in patients with PD. STN DBS can improve both movement function and gastrointestinal motility in patients with PD in the long term. The exact mechanism by which DBS improves gastric emptying requires further exploration.

Lateralized effects of deep brain stimulation in Parkinson's disease: evidence and controversies

The bilateral effects of deep brain stimulation (DBS) on motor and non-motor symptoms of Parkinson's disease (PD) have been extensively studied and reviewed. However, the unilateral effects-in particular, the potential lateralized effects of left- versus right-sided DBS-have not been adequately recognized or studied. Here we summarized the current evidence and controversies in the literature regarding the lateralized effects of DBS on motor and non-motor outcomes in PD patients. Publications in English language before February 2021 were obtained from the PubMed database and included if they directly compared the effects of unilateral versus contralateral side DBS on motor or non-motor outcomes in PD. The current literature is overall of low-quality and is biased by various confounders. Researchers have investigated mainly PD patients receiving subthalamic nucleus (STN) DBS while the potential lateralized effects of globus pallidus interna (GPi) DBS have not been adequately studied. Evidence suggests potential lateralized effects of STN DBS on axial motor symptoms and deleterious effects of left-sided DBS on language-related functions, in particular, the verbal fluency, in PD. The lateralized DBS effects on appendicular motor symptoms as well as other neurocognitive and neuropsychiatric domains remain inconclusive. Future studies should control for varying methodological approaches as well as clinical and DBS management heterogeneities, including symptom laterality, stimulation parameters, location of active contacts, and lead trajectories. This would contribute to improved treatment strategies such as personalized target selection, surgical planning, and postoperative management that ultimately benefit patients.

Mood Disorders and Anxiety in Parkinson's Disease: Current Concepts

Mood disorders and anxiety significantly impact the prognosis and disease course of Parkinson's disease. Non-motor symptoms of Parkinson's disease such as apathy, anhedonia, and fatigue overlap with diagnostic criteria for anxiety and depression, thus making accurate diagnosis of mood disorders in Parkinson's disease patients difficult. Furthermore, treatment options for mood disorders can produce motor complications leading to poor adherence and impaired quality of life in Parkinson's disease patients. This review aims to clarify the current state of diagnostic and treatment options pertaining to anxiety and mood disorders in Parkinson's disease. It explores both the pharmacologic and non-pharmacologic treatment modalities for various mood disorders in comorbid Parkinson's disease with a brief discussion of the future outlook of the field given the current state of the literature.

Loss of Prefrontal Cortical Higher Cognition with Uncontrollable Stress: Molecular Mechanisms, Changes with Age, and Relevance to Treatment

The newly evolved prefrontal cortex (PFC) generates goals for "top-down" control of behavior, thought, and emotion. However, these circuits are especially vulnerable to uncontrollable stress, with powerful, intracellular mechanisms that rapidly take the PFC "off-line." High levels of norepinephrine and dopamine released during stress engage α1-AR and D1R, which activate feedforward calcium-cAMP signaling pathways that open nearby potassium channels to weaken connectivity and reduce PFC cell firing. Sustained weakening with chronic stress leads to atrophy of dendrites and spines. Understanding these signaling events helps to explain the increased susceptibility of the PFC to stress pathology during adolescence, when dopamine expression is increased in the PFC, and with advanced age, when the molecular "brakes" on stress signaling are diminished by loss of phosphodiesterases. These mechanisms have also led to pharmacological treatments for stress-related disorders, including guanfacine treatment of childhood trauma, and prazosin treatment of veterans and civilians with post-traumatic stress disorder.

Revisiting eligibility for deep brain stimulation: Do preoperative mood symptoms predict outcomes in Parkinson's disease patients?

INTRODUCTION

Anxiety and depression are common in PD, occurring in an estimated 30%-40% of PD patients. However, the extent to which these emotional symptoms interfere with Deep Brain Stimulation (DBS) outcomes is not well established. This study examined the association between pre-operative emotional well-being and postsurgical cognitive, emotional, and motor performance in PD.

METHODS

Forty-nine PD patients underwent neurological, neuropsychological (global cognition, processing speed, language, visuospatial, memory), and emotional assessments pre- and post-DBS. Fifteen patients were administered the UPDRS. Patients were divided into Anxious (Anx; n = 21), Comorbid Anxious and Depressed (Anx + Dep; n = 15), and Emotionally Asymptomatic (EA; n = 13) based on BAI and BDI-II cutoffs, and compared on pre-post changes in neurocognitive, mood, and motor scores using analyses of covariance (ANCOVA), controlling for education, ethnicity, and disease duration.

RESULTS

Pre-DBS, there were no significant differences between the three groups on any neuropsychological measure. Overall change from pre-to post-DBS revealed declines on multiple cognitive measures and lower symptom endorsement on the BAI among all participants. No group differences were observed on neurocognitive measures, mood, or UPDRS.

CONCLUSIONS

PD patients with mild-moderate anxiety or comorbid anxiety/depression pre-DBS do not show greater cognitive, emotional, and motor changes post-DBS compared to emotionally asymptomatic patients. These data emphasize the importance of discussing potential DBS outcomes, while keeping in mind that psychiatric comorbidity should not necessarily exclude patients from DBS. The notion that premorbid mood symptoms could disqualify a candidate for surgery would be a disservice, as this group performs comparably to asymptomatic peers.

Deep brain stimulation targets for treating depression

Deep brain stimulation (DBS) is a new therapeutic approach for treatment-resistant depression (TRD). There is a preliminary evidence of the efficacy and safety of DBS for TRD in the subgenual anterior cingulate cortex, the ventral capsule/ventral striatum, the nucleus accumbens, the lateral habenula, the inferior thalamic peduncle, the medial forebrain bundle, and the bed nucleus of the stria terminalis. Optimal stimulation targets, however, have not yet been determined. Here we provide updated knowledge substantiating the suitability of each of the current and potential future DBS targets for treating depression. In this review, we discuss the future outlook for DBS treatment of depression in light of the fact that antidepressant effects of DBS can be achieved using different targets.

The Subthalamic Neurons are Activated by Both Orexin-A and Orexin-B

The subthalamic nucleus is an important nucleus in the indirect pathway of the basal ganglia circuit and therefore is involved in motor control under both normal and pathological conditions. Morphological studies reveal that the subthalamic nucleus receives relatively dense orexinergic projections originating from the hypothalamus. Both orexin-1 (OX₁) and orexin-2 (OX₂) receptors are expressed in the subthalamic nucleus. To explore the functions of orexinergic system in the subthalamic nucleus, extracellular electrophysiological recordings and behavioral tests were performed in the present study. Exogenous application of orexin-A significantly increased the spontaneous firing rate from 5.70 ± 0.66 Hz to 9.87 ± 1.18 Hz in 64.00% subthalamic neurons recorded. OX₁ receptors are involved in orexin-A-induced excitation. Application of orexin-B increased the firing rate from 7.47 ± 0.92 Hz to 11.85 ± 1.39 Hz in 80.95% subthalamic neurons recorded, entirely through OX₂ receptors. Both OX₁ and OX₂ receptor antagonists decreased the firing rate in 43.75% and 62.50% subthalamic neurons recorded respectively, suggesting the involvement of endogenous orexinergic system in the control of spontaneous firing activity. Further elevated body swing test revealed that microinjection of orexins and the receptor antagonists into the subthalamic nucleus induced contralateral-biased swing and ipsilateral-biased swing, respectively. Taken together, the present study suggests that orexins play important roles in the subthalamic nucleus which may provide further evidence for the involvement of subthalamic orexinergic tone in Parkinson's disease.

SIGNIFICANCE

Previous morphological studies indicate that the subthalamic nucleus receives orexinergic innervation and expresses both OX₁ and OX₂ receptors. Using in vivo multibarrel electrophysiological recordings, the present study revealed that exogenous application of orexin-A and orexin-B increased the spontaneous firing rate of the subthalamic neurons through OX₁ and OX₂ receptors. Endogenous orexinergic system was involved in the control of spontaneous firing of the subthalamic neurons. Further behavioral test revealed that intrasubthalamic application of orexins and the receptor antagonists induced biased swing behavior. The present study may provide further evidence for the involvement of subthalamic orexinergic tone in Parkinson's disease.

The Dominant-Subthalamic Nucleus Phenomenon in Bilateral Deep Brain Stimulation for Parkinson's Disease: Evidence from a Gait Analysis Study

Background

It has been suggested that parkinsonian [Parkinson’s disease (PD)] patients might have a “dominant” (DOM) subthalamic nucleus (STN), whose unilateral electrical stimulation [deep brain stimulation (DBS)] could lead to an improvement in PD symptoms similar to bilateral STN-DBS.

Objectives

Since disability in PD patients is often related to gait problems, in this study, we wanted to investigate in a group of patients bilaterally implanted for STN-DBS: (1) if it was possible to identify a subgroup of subjects with a dominant STN; (2) in the case, if the unilateral stimulation of the dominant STN was capable to improve gait abnormalities, as assessed by instrumented multifactorial gait analysis, similarly to what observed with bilateral stimulation.

Methods

We studied 10 PD patients with bilateral STN-DBS. A clinical evaluation and a kinematic, kinetic, and electromyographic (EMG) analysis of overground walking were performed—off medication—in four conditions: without stimulation, with bilateral stimulation, with unilateral right or left STN-DBS. Through a hierarchical agglomerative cluster analysis based on motor Unified Parkinson’s Disease Rating Scale scores, it was possible to separate patients into two groups, based on the presence (six patients, DOM group) or absence (four patients, NDOM group) of a dominant STN.

Results

In the DOM group, both bilateral and unilateral stimulation of the dominant STN significantly increased gait speed, stride length, range of motion of lower limb joints, and peaks of moment and power at the ankle joint; moreover, the EMG activation pattern of distal leg muscles was improved. The unilateral stimulation of the non-dominant STN did not produce any significant effect. In the NDOM group, only bilateral stimulation determined a significant improvement of gait parameters.

Conclusion

In the DOM group, the effect of unilateral stimulation of the dominant STN determined an improvement of gait parameters similar to bilateral stimulation. The pre-surgical identification of these patients, if possible, could allow to reduce the surgical risks and side effects of DBS adopting a unilateral approach.

Measures of impulsivity in Parkinson's disease decrease after DBS in the setting of stable dopamine therapy

INTRODUCTION

Recent evidence suggests deep brain stimulation can alter impulse control. Our objective was to prospectively evaluate the effects of subthalamic nucleus (STN) and globus pallidus internus (GPi) deep brain stimulation on impulse control disorders (ICDs) in the setting of a conservative dopamine reduction strategy.

METHODS

Patients (n = 37) undergoing de novo, unilateral STN or GPi DBS lead implantation were evaluated pre-operatively and 6-12 months post-operatively for the presence of ICDs using the Questionnaire for Impulsivity in Parkinson's disease (QUIP) and by clinical interview.

RESULTS

Of the patients enrolled, 23 underwent electrode implantation in the globus pallidus internus and 14 were implanted in the subthalamic nucleus. Mean time to long term follow-up was 9.7 ± 2.4 months. Post-operative LEDD was not significantly lower than pre-operative LEDD (pre-op: 1238.53 ± 128.47 vs. post-op: 1178.18 ± 126.43, p = 0.2972, paired t-test). Mean QUIP scores were significantly lower at follow up compared to pre-operative baseline (1.51 ± 0.45 vs. 2.51 ± 0.58, p = 0.0447, paired t-test). Patients with ICDs pre-operatively (n = 14, 37.8%) had significant improvement in QUIP scores at follow-up (6.00 ± 0.94 vs. 2.64 ± 0.98, p = 0.0014, paired t-test). Improvement was not uniform across the cohort: 1 patient with ICD at baseline developed worsening symptoms, and 4 patients with no ICD pre-operatively developed clinically significant ICDs post-operatively.

CONCLUSION

When LEDD is relatively unchanged following STN or GPi DBS for PD, ICD symptoms tend toward improvement, although worsening and emergence of new ICDs can occur. In the setting of stable LEDD, these findings suggest that the intrinsic effects of DBS may play a significant role in altering impulsive behavior.

Treatment of Sleep Dysfunction in Parkinson's Disease

OPINION STATEMENT

Impaired sleep and alertness affect the majority of Parkinson's disease (PD) patients, negatively impacting safety and quality of life. The etiology of impaired sleep-wake cycle in PD is multifactorial and encompasses medication side effects, nocturnal PD motor symptoms, and presence of co-existent sleep and neuropsychiatric disorders. The primary neurodegenerative process of PD involves brain regions that regulate the sleep-wake cycle, such as brainstem and hypothalamic nuclei. Sleep disorders in PD include insomnia, REM sleep behavior disorder (RBD), sleep disordered breathing (SDB), restless legs syndrome (RLS), and circadian disruption. Despite its high prevalence in the PD population, there is a paucity of clinical studies that have investigated treatment of sleep dysfunction associated with PD. Therefore, we aim to review available evidence and outline treatment strategies for improvement of disorders of sleep and wakefulness in PD patients. Evidence supporting the efficacy of pharmacological and non-pharmacological treatment strategies in PD is limited. There is thus a great need but also opportunity for development of well-designed clinical trials for impaired sleep and alertness in PD. Providing education about sleep hygiene and strategies for its implementation represents the initial step in management. Prompt diagnosis and treatment of co-existent primary sleep and psychiatric disorders are critical, as this may significantly improve sleep and alertness. While the optimal treatment for insomnia in PD has not been established, available strategies include cognitive-behavioral therapy, medications with soporific properties, and light therapy. Safety measures, clonazepam, and melatonin are the mainstay of treatment for RBD. Continuous positive airway pressure is an effective treatment for SDB in PD. The treatment algorithm for RLS associated with PD mirrors that used for idiopathic RLS. Circadian disruption has emerged as an important etiology of impaired sleep-wake cycles in PD, and circadian-based interventions hold promise for novel treatment approaches.