Review of delirium in patients with Parkinson's disease

Inferring when to move

Most of our movement consists of sequences of discrete actions at regular intervals-including speech, walking, playing music, or even chewing. Despite this, few models of the motor system address how the brain determines the interval at which to trigger actions. This paper offers a theoretical analysis of the problem of timing movements. We consider a scenario in which we must align an alternating movement with a regular external (auditory) stimulus. We assume that our brains employ generative world models that include internal clocks of various speeds. These allow us to associate a temporally regular sensory input with an internal clock, and actions with parts of that clock cycle. We treat this as process of inferring which clock best explains sensory input. This offers a way in which temporally discrete choices might emerge from a continuous process. This is not straightforward, particularly if each of those choices unfolds during a time that has a (possibly unknown) duration. We develop a route for translation to neurology, in the context of Parkinson's disease-a disorder that characteristically slows down movements. The effects are often elicited in clinic by alternating movements. We find that it is possible to reproduce behavioural and electrophysiological features associated with parkinsonism by disrupting specific parameters-that determine the priors for inferences made by the brain. We observe three core features of Parkinson's disease: amplitude decrement, festination, and breakdown of repetitive movements. Our simulations provide a mechanistic interpretation of how pathology and therapeutics might influence behaviour and neural activity.

Diagnostics and treatment of impulse control disorders, psychosis and delirium: systemic review-based recommendations - guideline "Parkinson's disease" of the German Society of Neurology

BACKGROUND AND OBJECTIVE

Impulse control disorders (ICD), psychosis and delirium are part of the spectrum of behavioural changes associated with Parkinson's disease (PD). The diagnostic and therapeutic management of these rather complex neuropsychiatric conditions has been updated in the clinical guideline by the German Society of Neurology (DGN).

METHODS

Recommendations are based on a systematic literature reviews, other relevant guidelines and expert opinion.

RESULTS

Patients receiving dopamine agonists (DA) therapy should be informed about the symptoms and risks of an ICD and should be routinely screened for ICD symptoms. In the presence of an ICD, DA should be reduced or discontinued and psychotherapeutic treatment may be considered. Non-oral therapies (levodopa/carbidopa intestinal gel infusion or deep brain stimulation) may also be an option for appropriate candidates. Psychosis in PD often has a gradual onset. Cognitive and affective disorders, psychiatric and medical comorbidities as well as polypharmacy are risk factors for a psychosis. Non-pharmacological treatments should be implemented as soon as possible and anti-parkinsonian medications should be adjusted/reduced if feasible. For psychosis associated with PD, quetiapine or clozapine should be used on an as-needed basis and for as short a time as is necessary, with safety monitoring. Delirium in PD may be underdiagnosed due to an overlap with chronic neuropsychiatric features of PD. Although transient by definition, delirium in PD can lead to permanent cognitive decline, motor impairment and increased mortality. Management of delirium includes pharmacological and non-pharmacological interventions.

CONCLUSION

The updated guideline encompasses the evidence-based diagnostic, non-pharmacological and pharmacological management of ICD, psychosis and delirium in PD.

Cognitive disorders in advanced Parkinson's disease: challenges in the diagnosis of delirium

Parkinson's disease (PD) is a neurodegenerative condition that is frequently associated with cognitive disorders. These can arise directly from the primary disease, or be triggered by external factors in susceptible individuals due to PD or other predisposing factors. The cognitive disorders encompass PD-associated cognitive impairment (PD-CI), delirium, PD treatment-associated cognitive side effects, cognitive non-motor fluctuations, and PD-associated psychosis. Accurate diagnosis of delirium is crucial because it often stems from an underlying disease that may be severe and require specific treatment. However, overlapping molecular mechanisms are thought to be involved in both delirium and PD, leading to similar clinical symptoms. Additionally, there is a bidirectional interaction between delirium and PD-CI, resulting in frequent concurrent processes that further complicate diagnosis. No reliable biomarker is currently available for delirium, and the diagnosis is primarily based on clinical criteria. However, the screening tools validated for diagnosing delirium in the general population have not been specifically validated for PD. Our review addresses the current challenges in the diagnosis of these cognitive disorders and highlights existing gaps within this field.

Delirium is more common and associated with worse outcomes in Parkinson's disease compared to older adult controls: results of two prospective longitudinal cohort studies

BACKGROUND

Inpatient prevalence of Parkinson's disease (PD) delirium varies widely across the literature. Delirium in general older populations is associated with adverse outcomes, such as increased mortality, dementia, and institutionalisation. However, to date there are no comprehensive prospective studies in PD delirium. This study aimed to determine delirium prevalence in hospitalised PD participants and the association with adverse outcomes, compared to a control group of older adults without PD.

METHODS

Participants were hospitalised inpatients from the 'Defining Delirium and its Impact in Parkinson's Disease' and the 'Delirium and Cognitive Impact in Dementia' studies comprising 121 PD participants and 199 older adult controls. Delirium was diagnosed prospectively using the Diagnostic and Statistical Manual of Mental Disorders 5th Edition criteria. Outcomes were determined by medical note reviews and/or home visits 12 months post hospital discharge.

RESULTS

Delirium was identified in 66.9% of PD participants compared to 38.7% of controls (p < 0.001). In PD participants only, delirium was associated with a significantly higher risk of mortality (HR = 3.3 (95% confidence interval [CI] = 1.3-8.6), p = 0.014) and institutionalisation (OR = 10.7 (95% CI = 2.1-54.6), p = 0.004) 12 months post-discharge, compared to older adult controls. However, delirium was associated with an increased risk of developing dementia 12 months post-discharge in both PD participants (OR = 6.1 (95% CI = 1.3-29.5), p = 0.024) and in controls (OR = 13.4 (95% CI = 2.5-72.6), p = 0.003).

CONCLUSION

Delirium is common in hospitalised PD patients, affecting two thirds of patients, and is associated with increased mortality, institutionalisation, and dementia. Further research is essential to understand how to accurately identify, prevent and manage delirium in people with PD who are in hospital.

Causal relationships between delirium and Parkinson's disease: a bidirectional two-sample Mendelian randomization study

BACKGROUND

Previous observational studies have suggested a notably elevated prevalence of delirium in individuals diagnosed with Parkinson's disease (PD), thereby implying a potential increased susceptibility to delirium among PD patients. However, it is imperative to acknowledge that observational studies inherently possess limitations, rendering it arduous to establish a definitive causal or reverse causal association between delirium and PD.

METHODS

To explore the relationship between delirium and PD, a bidirectional two-sample Mendelian randomization (MR) was conducted using summary statistics obtained from genome-wide association studies. The main analysis was performed using the inverse-variance weighted (IVW) method, with further analyses conducted using MR Egger, weighted median, and weighted mode to ensure accuracy of findings. Additionally, Cochran's Q statistics and MR Egger intercept were utilized to assess heterogeneity and horizontal pleiotropy, respectively.

RESULTS

According to the results obtained from the IVW model, no compelling evidence was found to support a potential causal association between delirium and PD (IVW: odds ratio [OR]: 0.996, 95% confidence interval CI 0.949-1.043, P = 0.845). Additionally, in the reverse direction, based on the results obtained from the IVW model, no significant evidence was found to support a causal association between PD and delirium (IVW: OR: 1.078, 95%CI  0.960-1.204, P = 0.225). A sensitivity analysis verified the reliability of the results.

CONCLUSION

According to the MR findings, a bidirectional causal relationship between delirium and PD is not observed. It is crucial to conduct further research in clinical practice to investigate the association between delirium and the risk of PD.

Risk Factors for Postoperative Delirium Severity After Deep Brain Stimulation Surgery in Parkinson's Disease

Background

Postoperative delirium (POD) is a serious complication following deep brain stimulation (DBS) but only received little attention. Its main risk factors are higher age and preoperative cognitive deficits. These are also main risk factors for long-term cognitive decline after DBS in Parkinson's disease (PD).

Objective

To identify risk factors for POD severity after DBS surgery in PD.

Methods

57 patients underwent DBS (21 female; age 60.2±8.2; disease duration 10.5±5.9 years). Preoperatively, general, PD- and surgery-specific predictors were recorded. Montreal Cognitive Assessment and the neuropsychological test battery CANTAB ConnectTM were used to test domain-specific cognition. Volumes of the cholinergic basal forebrain were calculated with voxel-based morphometry. POD severity was recorded with the delirium scales Confusion Assessment Method for Intensive Care Unit (CAM-ICU) and Nursing Delirium Scale (NU-DESC). Spearman correlations were calculated for univariate analysis of predictors and POD severity and linear regression with elastic net regularization and leave-one-out cross-validation was performed to fit a multivariable model.

Results

21 patients (36.8%) showed mainly mild courses of POD following DBS. Correlation between predicted and true POD severity was significant (spearman rho = 0.365, p = 0.001). Influential predictors were age (p < 0.001), deficits in attention and motor speed (p = 0.002), visual learning (p = 0.036) as well as working memory (p < 0.001), Nucleus basalis of Meynert volumes (p = 0.003) and burst suppression (p = 0.005).

Conclusions

General but also PD- and surgery-specific factors were predictive of POD severity. These findings underline the multifaceted etiology of POD after DBS in PD. Valid predictive models must therefore consider general, PD- and surgery-specific factors.

Documentation and diagnosis of delirium in Parkinson's disease

OBJECTIVE

To assess the accuracy of documentation of the symptoms and diagnosis of delirium in medical notes of inpatients with Parkinson's disease (PD).

METHODS

The DETERMINE-PD pilot study assessed PD inpatients over 4-months. Delirium prevalence was classified prospectively using a standardized assessment at a single visit on the basis of Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5) criteria. Incident delirium was diagnosed retrospectively using detailed clinical vignettes and validated consensus method. Inpatient medical notes and discharge summaries of those with delirium were reviewed for documentation of symptoms, diagnosis and follow-up.

RESULTS

Forty-four PD patients consented to take part in the study, accounting for 53 admissions. We identified 30 cases (56.6%) of delirium during the participants' stay in hospital. Of those with delirium identified by the research team, delirium symptoms were documented in the clinical notes of 72.3%; 37.9% had a delirium diagnosis documented. Older patients were more likely to have delirium (p = 0.027) and have this diagnosis documented (p = 0.034). Time from documentation of symptoms to diagnosis ranged from <24 h to 7 days (mean 1.6 ± 4.4 days). Hypoactive delirium was significantly less likely to have been identified and formally diagnosed (63% of not documented were hypoactive vs. 37% hyperactive, mixed or unclear, p = 0.016). Only 11.5% of discharge summaries included diagnosis of delirium.

CONCLUSION

Delirium in PD is common. Documentation of symptoms of delirium was common; however, fails to lead to a documentation of diagnosis in over half of admissions with delirium and was even less commonly communicated in the Primary Care discharge summaries. This highlights the need for increased education about delirium symptomatology and diagnosis in PD.

Using Machine Learning Algorithms to Predict High-Risk Factors for Postoperative Delirium in Elderly Patients

Purpose

Postoperative delirium (POD) is a common postoperative complication in elderly patients, and it greatly affects the short-term and long-term prognosis of patients. The purpose of this study was to develop a machine learning model to identify preoperative, intraoperative and postoperative high-risk factors and predict the occurrence of delirium after nonbrain surgery in elderly patients.

Patients and Methods

A total of 950 elderly patients were included in the study, including 132 patients with POD. We collected 30 characteristic variables, including patient demographic characteristics, basic medical history, preoperative examination characteristics, type of surgery, and intraoperative information. Three machine learning algorithms, multilayer perceptron (MLP), extreme gradient boosting (XGBoost), and k-nearest neighbor algorithm (KNN), were applied to construct the model, and the k-fold cross-validation method, ROC curve, calibration curve, decision curve analysis (DCA) and external validation were used for model evaluation.

Results

XGBoost showed the best performance among the three prediction models. The ROC curve results showed that XGBoost had a high area under the curve (AUC) value of 0.982 in the training set; the AUC value in the validation set was 0.924, and the prediction model was highly accurate. The k-fold cross-validation method was used for internal validation, and the XGBoost model was stable The calibration curve showed high predictive power of the XGBoost model. The DCA curve showed a higher benefit rate for patients who received interventional treatment under the XGBoost model. The AUC value for the external validation set was 0.88, indicating that the predictive model was extrapolative.

Conclusion

The prediction model of POD derived from the machine learning algorithm in this study has high prediction accuracy and clinical utility, which is beneficial for clinicians to diagnose and treat patients in a timely manner.

Nomogram for Prediction of Postoperative Delirium after Deep Brain Stimulation of Subthalamic Nucleus in Parkinson’s Disease under General Anesthesia

Introduction. Postoperative delirium can increase cognitive impairment and mortality in patients with Parkinson’s disease. The purpose of this study was to develop and internally validate a clinical prediction model of delirium after deep brain stimulation of the subthalamic nucleus in Parkinson’s disease under general anesthesia. Methods. We conducted a retrospective observational cohort study on the data of 240 patients with Parkinson’s disease who underwent deep brain stimulation of the subthalamic nucleus under general anesthesia. Demographic characteristics, clinical evaluation, imaging data, laboratory data, and surgical anesthesia information were collected. Multivariate logistic regression was used to develop the prediction model for postoperative delirium. Results. A total of 159 patients were included in the cohort, of which 38 (23.90%) had postoperative delirium. Smoking (OR 4.51, 95% CI 1.56–13.02, $p<0.01$ ) was the most important risk factor; other independent predictors were orthostatic hypotension (OR 3.42, 95% CI 0.90–13.06, $p=0.07$ ), inhibitors of type-B monoamine oxidase (OR 3.07, 95% CI 1.17–8.04, $p=0.02$ ), preoperative MRI with silent brain ischemia or infarction (OR 2.36, 95% CI 0.90–6.14, $p=0.08$ ), Hamilton anxiety scale score (OR 2.12, 95% CI 1.28–3.50, $p<0.01$ ), and apolipoprotein E level in plasma (OR 1.48, 95% CI 0.95–2.29, $p=0.08$ ). The area under the receiver operating characteristic curve (AUC) was 0.76 (95% CI 0.66–0.86). A nomogram was established and showed good calibration and clinical predictive capacity. After bootstrap for internal verification, the AUC was 0.74 (95% CI 0.66–0.83). Conclusion. This study provides evidence for the independent inducing factors of delirium after deep brain stimulation of the subthalamic nucleus in Parkinson’s disease under general anesthesia. By predicting the development of delirium, our model may identify high-risk groups that can benefit from early or preventive intervention.

[Anaesthesia and Perioperative Management for Patients with Parkinson's Disease]

Idiopathic Parkinson's syndrome is associated with the loss of dopaminergic cells. It is defined by the presence of akinesia together with one of the cardinal symptoms: rigor, tremor, or postural instability. As the perioperative management of these patients can be challenging and they have an increased perioperative risk, every anaesthesiologist should know some special features. If a patient with Parkinson's disease does not receive the required amount of dopa, akinetic crisis may occur. Moreover, the administration of dopamine-antagonistic drugs can trigger a malignant neuroleptic syndrome. These are life-threatening clinical pictures that require intensive medical treatment. Therefore, patients with Parkinson's disease should be enabled to keep the period without the intake of the specific medication as short as possible. General anaesthesia should be performed with short acting anaesthetics and a regional anaesthesia might be beneficial. Besides, all dopamine antagonists sometimes used for prophylaxis or therapy of delirium or PONV (haloperidol, metoclopramide) are contraindicated. Alternatives are short-acting benzodiazepines, atypical neuroleptics and domperidone.

Spotlight on non-motor symptoms and Covid-19

The Coronavirus Disease 2019 (Covid-19) pandemic has profoundly affected the quality of life (QoL) and health of the general population globally over the past 2 years, with a clear impact on people with Parkinson's Disease (PwP, PD). Non-motor symptoms have been widely acknowledged to hold a vital part in the clinical spectrum of PD, and, although often underrecognized, they significantly contribute to patients' and their caregivers' QoL. Up to now, there have been numerous reports of newly emerging or acutely deteriorating non-motor symptoms in PwP who had been infected by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), while some of these symptoms, like fatigue, pain, depression, anxiety and cognitive impairment, have also been identified as part of the long-COVID syndrome due to their persistent nature. The subjacent mechanisms, mediating the appearance or progression of non-motor symptoms in the context of Covid-19, although probably multifactorial in origin, remain largely unknown. Such mechanisms might be, at least partly, related solely to the viral infection per se or the lifestyle changes imposed during the pandemic, as many of the non-motor symptoms seem to be prevalent even among Covid-19 patients without PD. Here, we summarize the available evidence and implications of Covid-19 in non-motor PD symptoms in the acute and chronic, if applicable, phase of the infection, with a special reference on studies of PwP.

Evaluation of Bedside Tests of Attention and Arousal Assessing Delirium in Parkinson's Disease, Dementia, and Older Adults

BACKGROUND

Delirium is a serious acute neuropsychiatric condition associated with altered attention and arousal.

OBJECTIVE

To evaluate simple bedside tests for attention and arousal to detect delirium in those with and without Parkinson's disease (PD) and dementia.

METHODS

Participants from two prospective delirium studies were pooled comprising 30 with PD without cognitive impairment, 24 with Lewy body cognitive impairment (PD dementia or dementia with Lewy bodies), 16 with another dementia and 179 PD and dementia-free older adults. Participants completed standardised delirium assessments including tests of attention: digit span, Memorial Delirium Assessment Scale (MDAS) attention and months of the year backwards; and arousal: Glasgow Coma Scale (GSC), Observational Scale of Level of Arousal (OSLA), Modified Richmond Agitation Scale and MDAS consciousness. Delirium was diagnosed using the DSM-5 criteria.

RESULTS

On their first admission, 21.7%participants had prevalent delirium. Arousal measures accurately detected delirium in all participants (p < 0.01 for all), but only selected attention measures detected delirium in PD and dementia. In PD and dementia-free older adults, impaired digit span and OSLA were the optimal tests to detect delirium (area under the curve [AUC] = 0.838, p < 0.001) while in PD and dementia the optimal tests were MDAS attention and GCS (AUC=0.90 and 0.84, respectively, p < 0.001 for both).

CONCLUSION

Simple bedside tests of attention and arousal at a single visit could accurately detect delirium in PD, dementia and PD and dementia-free older adults; however, the optimal tests differed between groups. Combined attention and arousal scores increased accuracy, which could have clinical utility to aid the identification of delirium neurodegenerative disorders.

Parkinson's disease and Covid-19: Is there an impact of ethnicity and the need for palliative care

Under the traditional models of care for People with Parkinson's Disease (PD, PwP), many of their needs remain unmet and a substantial burden of motor and non-motor symptoms they experience may not be tackled sufficiently. An introduction of palliative care (PC) interventions early in the course of PD offers profound benefits: it may improve quality of life of patients, their families and caregivers through the prevention and relief of medical symptoms, while, at the same time, emphasizing their emotional needs and spiritual wellbeing, establishing goals of care, and engaging in the advance care planning (ACP).

The ongoing Coronavirus Disease 2019 (Covid-19) pandemic poses an unprecedented set of challenges for PwP and has in many ways (both directly and indirectly) magnified their suffering, thus rapidly raising the demand for PC interventions. Covid-19, as well as the repercussions of prolonged mobility restrictions and limited health-care access might exacerbate the severity of PD motor symptoms and interact negatively with a range of non-motor symptoms, with a detrimental effect on quality of life. Greater motor disability, higher amount of levodopa-induced motor fluctuations with an increased daily off-time, fatigue, anxiety, depression, sleep disturbances, pain and worsening of cognitive complaints might dominate the clinical presentation in PwP during the Covid-19 pandemic, alongside raising psychological and spiritual concerns and anticipatory grief.

Here, we aim to provide a foundation for pragmatic and clinically orientated PC approach to improve quality of life and relieve suffering of PwP in the context of the current, ongoing Covid-19 pandemic.

Treatment paradigms in Parkinson's Disease and Covid-19

People with Parkinson's Disease (PwP) may be at higher risk for complications from the Coronavirus Disease 2019 (Covid-19) due to older age and to the multi-faceted nature of Parkinson's Disease (PD) per se, presenting with a variety of motor and non-motor symptoms. Those on advanced therapies may be particularly vulnerable. Taking the above into consideration, along with the potential multi-systemic impact of Covid-19 on affected patients and the complications of hospitalization, we are providing an evidence-based guidance to ensure a high standard of care for PwP affected by Covid-19 with varying severity of the condition. Adherence to the dopaminergic medication of PwP, without abrupt modifications in dosage and frequency, is of utmost importance, while potential interactions with newly introduced drugs should always be considered. Treating physicians should be cautious to acknowledge and timely address any potential complications, while consultation by a neurologist, preferably with special knowledge on movement disorders, is advised for patients admitted in non-neurological wards. Non-pharmacological approaches, including the patient's mobilization, falls prevention, good sleep hygiene, emotional support, and adequate nutritional and fluid intake, are essential and the role of telemedicine services should be strengthened and encouraged.

Urinary Tract Infection in Parkinson's Disease

Urinary tract infection (UTI) is a common precipitant of acute neurological deterioration in patients with Parkinson's disease (PD) and a leading cause of delirium, functional decline, falls, and hospitalization. Various clinical features of PD including autonomic dysfunction and altered urodynamics, frailty and cognitive impairment, and the need for bladder catheterization contribute to an increased risk of UTI. Sepsis due to UTI is a feared consequence of untreated or undertreated UTI and a leading cause of morbidity in PD. Emerging research suggests that immune-mediated brain injury may underlie the pathogenesis of UTI-induced deterioration of PD symptoms. Existing strategies to prevent UTI in patients with PD include use of topical estrogen, prophylactic supplements, antibiotic bladder irrigation, clean catheterization techniques, and prophylactic oral antibiotics, while bacterial interference and vaccines/immunostimulants directed against common UTI pathogens are potentially emerging strategies that are currently under investigation. Future research is needed to mitigate the deleterious effects of UTI in PD.

First delirium episode in Parkinson's disease and parkinsonism: incidence, predictors, and outcomes

To define the incidence, predictors and prognosis of the first hospital delirium episode in Parkinson’s disease (PD) and atypical parkinsonism (AP), we identified the first hospital episode of delirium after diagnosis in the Parkinsonism Incidence in North-East Scotland (PINE) study, a prospective community-based incidence cohort of parkinsonism, using chart-based criteria to define delirium. Of 296 patients (189=PD, 107=AP [dementia with Lewy bodies, progressive supranuclear palsy, multiple system atrophy, vascular parkinsonism]), 152 developed delirium (PD = 98, AP = 54). Incidence of first hospital delirium episode per 100 person years was 8.1 (95% confidence interval [CI] 6.6–9.9) in PD and 18.5 (95% CI 13.9–24.7) in AP. Independent predictors of delirium were atypical parkinsonism (Hazard ratio [HR] vs PD = 2.83 [95% CI 1.60–5.03], age in PD but not in AP (HR for 10-year increase 2.29 [95% CI 1.74–3.02]), baseline MMSE (HR = 0.94 [95% CI 0.89–0.99]), APOE ε4 in PD (HR 2.16 [95% CI 1.15–4.08]), and MAPT H1/H1 in PD (HR 2.08 [95% CI 1.08–4.00]). Hazards of dementia and death after delirium vs before delirium were increased (dementia: HR = 6.93 [95% CI 4.18–11.48] in parkinsonism; death: HR = 3.76 [95% CI 2.65–5.35] in PD, 1.59 [95% CI 1.04–2.42] in AP). Delirium is a common non-motor feature of PD and AP and is associated with increased hazards of dementia and mortality. Whether interventions for early identification and treatment improve outcomes requires investigation.

Outcomes of Patients With Parkinson Disease Undergoing Cervical Spine Surgery for Radiculopathy and Myelopathy With Minimum 2-Year Follow-up

STUDY DESIGN

This was a retrospective cohort analysis.

OBJECTIVE

To identify the impact of Parkinson disease (PD) on 2-year postoperative outcomes following cervical spine surgery (CSS).

SUMMARY OF BACKGROUND DATA

(PD) patients are prone to spine malalignment and surgical interventions, yet little is known regarding outcomes of CSS among PD patients.

MATERIALS AND METHODS

All patients from the Statewide Planning and Research Cooperative System with cervical radiculopathy or myelopathy who underwent CSS were included; among these, those with PD were identified. PD and non-PD patients (n=64 each) were 1:1 propensity score-matched by age, sex, race, surgical approach, and Deyo-Charlson Comorbidity Index (DCCI). Demographics, hospital-related parameters, and adverse postoperative outcomes were compared between cohorts. Logistic regression identified predictive factors for outcomes.

RESULTS

Overall, patient demographics were comparable between cohorts, except that DCCI was higher in PD patients (1.28 vs. 0.67, P=0.028). PD patients had lengthier mean hospital stays than non-PD patients (6.4 vs. 4.1 d, P=0.046). PD patients also incurred comparable total hospital expenses ($69,565 vs. $57,388, P=0.248). Individual medical complication rates were comparable between cohorts; though PD patients had higher rates of postoperative altered mental status (4.7% vs. 0%, P=0.08) and acute renal failure (10.9% vs. 3.1%, P=0.084), these differences were not significant. Yet, PD patients experienced higher rates of overall medical complications (35.9% vs. 18.8%, P=0.029). PD patients had comparable rates of individual and overall surgical complications. The PD cohort underwent higher reoperation rates (15.6% vs. 7.8%, P=0.169) compared with non-PD patients, though this difference was not significant. Of note, PD was not a significant predictor of overall 2-year complications (odds ratio=1.57, P=0.268) or reoperations (odds ratio=2.03, P=0.251).

CONCLUSION

Overall medical complication rates were higher in patients with PD, while individual medical complications as well as surgical complication and reoperation rates after elective CSS were similar in patients with and without PD, though PD patients required longer hospital stays. Importantly, a baseline diagnosis of PD was not significantly associated with adverse two-year medical and surgical complications. This data may improve counseling and risk-stratification for PD patients before CSS.

LEVEL OF EVIDENCE

Level III.

Emerging Perspectives in the Diagnosis and Management of Depression and Psychosis in Parkinson's Disease

Collapse

Naloxone Alleviate the Severity of Delirium in Hospitalized Patients With Parkinsonism: Three Case Reports

Purpose: Delirium is common in geriatric with Parkinson's disease (PD). Treatments for delirium have generally been neuroleptics; however, antipsychotics have potential effect to block striatal dopamine D2 receptors and worsen symptom of parkinsonism. We explored whether naloxone can alleviate delirium in PD and other forms of parkinsonism. Patients and Methods: Patients with parkinsonism who met the delirium criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) received naloxone infusions once or twice daily. Treatment effects were evaluated by the delirium rating scale-revised 98 (DRS-R98), including non-cognitive and cognitive subscales; the Richmond agitation-sedation scale (RASS); and the mini mental status examination (MMSE). Results: Two patients with primary parkinsonism, one with vascular PD were observed. The daily dose of naloxone was 2.08 ± 0.64 mg (range: 1-4 mg). Medication time last from 1 h to 7 days without side effects observed. Following with naloxone infusions, DRS-R98 scores decreased within 12 h and MMSE scores increased. The psychotic symptoms, disorientation, and attention deficits were alleviated significantly, while RASS scores decreased with naloxone treatment. Conclusion: Naloxone alleviated psychotic symptoms, improved cognitive dysfunction, and irritability in patients with delirium in the context of PD. The preliminary findings point out that the opioid system may be involved in the pathophysiology of delirium, which may be one of potential treat targets for delirium of PD.

Follow-Up of Advanced Parkinson's Disease Patients after Clinical or Surgical Emergencies: A Practical Approach

Background

Patients with advanced stage Parkinson's disease (PD) typically present with a myriad of motor and nonmotor symptoms in addition to comorbidities and, as a consequence, polypharmacy.

Objective

To analyze a series of cases of advanced PD in which a clinical or surgical emergency played a trigger role in the irreversible progression of landmarks of the course of the disease.

Methods

Data were collected during a 13-month observational period of a cohort of 230 PD patients, in 751 medical appointments. We included a total of 13 (5.65% of the total number) patients with advanced PD defined by Hoehn & Yahr (H&Y) stage ≥3 who presented with various clinical and surgical complications which, with the contribution of drug interventions, led to significant worsening of patients' overall clinical condition.

Results

Hip fractures and infections were the most common complications identified. As part of this scenario, most patients presented with delirium, often requiring treatment with dopamine receptor blocking agents and/or had dopaminergic treatment withdrawn. Upon reassessment after 3 months, all patients remained bed or wheel chair bound (H&Y 5) and presented significant worsening of their UPDRS part III score of at least 10 points (mean 51.5 ± 3.3; paired t-test two-tailed p < 0.0001 compared to baseline). The mean dose of levodopa at baseline was 907.7 ± 149.8 mg (600–1200) and significantly higher (paired t-test two-tailed p < 0.0001) on follow-up, 1061.5 ± 175.8 mg (700–1300).

Conclusion

Clinical and surgical emergencies are major determinants for a progression of PD to more advanced stages.

A Review of Multimodal Hallucinations: Categorization, Assessment, Theoretical Perspectives, and Clinical Recommendations

Hallucinations can occur in different sensory modalities, both simultaneously and serially in time. They have typically been studied in clinical populations as phenomena occurring in a single sensory modality. Hallucinatory experiences occurring in multiple sensory systems-multimodal hallucinations (MMHs)-are more prevalent than previously thought and may have greater adverse impact than unimodal ones, but they remain relatively underresearched. Here, we review and discuss: (1) the definition and categorization of both serial and simultaneous MMHs, (2) available assessment tools and how they can be improved, and (3) the explanatory power that current hallucination theories have for MMHs. Overall, we suggest that current models need to be updated or developed to account for MMHs and to inform research into the underlying processes of such hallucinatory phenomena. We make recommendations for future research and for clinical practice, including the need for service user involvement and for better assessment tools that can reliably measure MMHs and distinguish them from other related phenomena.

Exosome α-Synuclein Release in Plasma May be Associated With Postoperative Delirium in Hip Fracture Patients

Background: Little is known about the underlying mechanisms of the similarities in the core features of postoperative delirium (POD) and α-synuclein (α-syn)-related cognitive disorders. We herein investigated associations between fluctuated levels of exosomal α-syn in the plasma and POD presentation in geriatric hip fracture patients.

Methods: We conducted an observational, prospective, and 1:1 matched (on age older than 65, hip fracture diagnosis, American Society of Anesthesiologist’ (ASA) physical status, duration of surgery, and intraoperative bleeding) case-control study: POD cases and non-POD controls were selected from the overall cohort by using Confusion Assessment Method (CAM). Delirium severity was measured by the Memorial Delirium Assessment Scale (MDAS). Plasma exosome levels of α-syn were examined preoperatively and at the time that POD was diagnosed, by using an established immunocapture technology based on a putative brain-cell-specific marker. Circulating concentrations of interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were also determined. The relationship between α-syn levels and POD risk, as well as the association between α-syn and MDAS scores and plasma cytokines, were assessed.

Results: POD incidence was 8.4% (17/202). Postoperative α-syn were either elevated or lowered. As primary outcome variables, the change of α-syn in POD patients was significantly higher than non-POD ones (21.0 ± 29.3 pg.ml⁻¹ vs.1.9 ± 20.0, P = 0.047). The α-syn alteration was positively correlated to MDAS (r = 0.436, P = 0.010) and the change of IL-6 (r = 0.383, P = 0.025).

Conclusions: Exosome α-syn release in plasma may be associated with the POD development which might be due to systemic inflammation.

Clinical Trial Registration: www.clinicaltrials.gov, identifier ChiCTR-IPR-17012301.

Prior Presentation: The abstract of this work has been selected for presentation in the 2019 ANESTHESIOLOGY Journal Symposium “What’s New with the old,” and it has been present in the ASA 2019 annual meeting October 21st, 2019 in Florida.

Neuropsychiatric symptoms in Parkinson's disease: aetiology, diagnosis and treatment

Historically, Parkinson's disease was viewed as a motor disorder and it is only in recent years that the spectrum of non-motor disorders associated with the condition has been fully recognised. There is a broad scope of neuropsychiatric manifestations, including depression, anxiety, apathy, psychosis and cognitive impairment. Patients are more predisposed to delirium, and Parkinson's disease treatments give rise to specific syndromes, including impulse control disorders, dopamine agonist withdrawal syndrome and dopamine dysregulation syndrome. This article gives a broad overview of the spectrum of these conditions, describes the association with severity of Parkinson's disease and the degree to which dopaminergic degeneration and/or treatment influence symptoms. We highlight useful assessment scales that inform diagnosis and current treatment strategies to ameliorate these troublesome symptoms, which frequently negatively affect quality of life.

[Delirium in idiopathic Parkinson's disease]

BACKGROUND

The development of delirium in patients with idiopathic Parkinson's disease (IPD) is a feared complication, which is often associated with sustained worsening of motor symptoms and psychopathological sequelae. Little is known regarding the prevalence and incidence rates, course and prognosis. Clinical studies from which recommendations for evidence-based management of delirium in IPD can be derived are lacking.

OBJECTIVE

To summarize the state of the art regarding epidemiological and clinical features of delirium in IPD. Discussion of prevention strategies and non-pharmacological and pharmacological treatment options.

METHODS

A literature search was carried out in PubMed.

RESULTS

The IPD is an independent risk factor for the development of delirium. Patients with IPD show poorer clinical outcome frequently with cognitive worsening and motor complications following development of delirium.

CONCLUSION

So far no validated rating scales for recognition and course evaluation of delirium in IPD are available. Preventive strategies and non-pharmacological measures should be consistently implemented to improve management. There are insufficient data concerning pharmacotherapy with quetiapine and clozapine, whereas other neuroleptics are contraindicated for delirium in IPD due to antidopaminergic side effects.

Association between postoperative delirium and mortality in elderly patients undergoing hip fractures surgery: a meta-analysis

INTRODUCTION

Postoperative delirium (POD) is a common complication in elderly surgical patients. Patients undergoing hip fractures surgery who are often characterized by advanced age could be particularly prone to suffering POD. We performed a meta-analysis to assess the association between POD and mortality in elderly patients undergoing hip fractures surgery. This meta-analysis included twenty-one cohort studies, and the pooled outcomes demonstrated that approximated one-fourth of patients undergoing hipfracture surgery would develop POD, and delirium increased the mortality in these patients.

METHODS

We searched PubMed, Embase, Web of Science, and Scopus for studies that investigated the effect of POD on mortality in elderly patients undergoing hip fracture surgery. Two reviewers independently selected studies, assessed quality, and extracted data. Statistical analyses were performed by STATA 14.0 and RevMan 5.3. Risk ratios (RRs) with 95% confidence intervals (CIs) were derived using random or fixed-effects model.

RESULTS

Twenty-one cohort studies enrolling a total of 6288 patients were included, and the pooled prevalence (95% CI) of POD was 28% (23-34%). POD was associated with an increase in perioperative mortality (30-day or in-hospital mortality) [12 studies, 3123 patients, relative risk (RR) (95% CI) 2.79 (1.97-3.93)], 6-month mortality [6 studies, 1673 patients, 2.51 (1.99-3.16)], 1-year mortality [6 studies, 1896 patients, 1.98 (1.62-2.41)], and more than 1-year mortality [8 studies, 1926 patients, 2.06 (1.60-2.64)].

CONCLUSIONS

Our meta-analysis demonstrated that approximated one-fourth of patients undergoing hip fracture surgery would develop POD, and delirium increased the short-term and long-term mortality in these patients.

Multimorbidity and Frailty: Tackling Complexity in Parkinson's Disease

Parkinson's disease (PD) is a condition that predominantly affects older people. It is imperative that clinical management considers the other significant illnesses that people with PD accumulate as they age in conjunction with their resilience to cope with physiological change. Multimorbidity and frailty act synergistically to heighten the risk of adverse outcomes for older people with PD. These states are associated with increased likelihood of hospitalization, polypharmacy, adverse drug effects including the anticholinergic burden of medications, drug-disease and drug-drug interactions. Management should be integrated, holistic and individualised to meticulously balance the risks of interventions considering the vulnerability of the individual to recover from disturbance to their environmental, physical and cognitive equilibrium.

Parkinson's Disease in Intensive Care Unit: An Observational Study of Frequencies, Causes, and Outcomes

Objective:

To analyze the frequency, causes, and outcomes of admission to the Intensive Care Unit (ICU) among Parkinson's disease (PD) population so that preventive measures can be developed.

Methods:

We prospectively observed patients with diagnosis of PD admitted to ICU from January 2014 to December 2016. Based on etiology for hospital admission, they were divided into two groups – related to PD (further divided into direct or indirect) or not associated with PD at all. Etiology for hospitalization was determined from history and investigational data. The primary outcome was death or discharge from the hospital. Factors contributing to ICU admission were analyzed by comparing these patients with a cohort of 50 PD patients admitted to the neurology ward during the same study period. All values were expressed as mean (standard deviation) and percentages using SPSS version 16.0.

Results:

Fifty-three (36%) out of a total of 146 patients required ICU admission. Most common causes leading to admission in decreasing order of frequency were fever (34%), delirium (16%), falls (12%), encephalopathy (8%), gastrointestinal emergencies (6%); while direct disease-related severe dyskinesias were seen only in two patients (4%). 13.7% needed mechanical ventilation and mean duration of ventilation was 5.94 days with mortality rate of 20%. Significant factors predicting ICU admission, and thus, poor outcomes were age >65 years, history of previous admission within the last 12 months, delirium, and hypoalbuminemia. There was no significant association between the incidence of ICU admission and duration of disease or severity of the disease.

Conclusions:

Poor outcome in PD patients is due to systemic causes, hence multidisciplinary teamwork may improve outcome in these patients.

Defining delirium in idiopathic Parkinson's disease: A systematic review

BACKGROUND

Parkinson's disease patients may be at increased risk of delirium and developing adverse outcomes, such as cognitive decline and increased mortality. Delirium is an acute state of confusion that has overlapping symptoms with Parkinson's dementia, making it difficult to identify. This study aimed to determine the diagnostic criteria, prevalence, management strategies and outcomes of delirium in Parkinson's through a systematic review of the literature.

METHODS

Seven databases were used to identify all articles published before February 2017 comprising two key terms: "Parkinson's Disease" and "delirium". Data were extracted from studies meeting predefined inclusion criteria.

RESULTS

Twenty articles were identified. Delirium prevalence in Parkinson's ranged from 0.3 to 60% depending on setting; a diagnosis of Parkinson's was associated with an increased risk of developing delirium. Delirium was identified/diagnosed using seven different criteria. Delirium may be associated with an increased length of hospital stay and worsening motor symptoms. We did not identify any studies examining the management of delirium in Parkinson's.

DISCUSSION

This review highlights the paucity of well-designed, appropriately powered studies investigating delirium in Parkinson's. The results suggest that delirium is a significant issue in people with Parkinson's and that having delirium may be a risk factor for adverse outcomes, particularly in inpatient settings. Further prospective research is needed to accurately determine the prevalence of delirium in Parkinson's, its management strategies and outcomes, and to evaluate diagnostic criteria to differentiate between the overlapping symptoms of Parkinson's and delirium.

Quality of Life of Caregivers of Individuals With Parkinson's Disease

PURPOSE

This study aimed to construct a structural equation model to predict the quality of life of caregivers of individuals with Parkinson's disease.

DESIGN

A cross-sectional survey using a structured questionnaire in South Korea.

METHODS

A total of 208 subjects participated in this study from August 31 to November 26, 2015. The questionnaire included caregiving appraisal, social support, educational program needs, and the Parkinson's Disease Questionnaire-Carer.

FINDINGS

Participants were either spouses (46.2%) or adult children (45.2%) of individuals with Parkinson's disease. The mean score obtained on the caregiver's quality of life was 40.94 ± 25.30. Social support, caregiving appraisal, and educational program needs were the predictors, explaining 67.0% of the variance in caregivers' quality of life.

CONCLUSIONS

Predicting the quality of life is useful for the development of support resources for caregivers of individuals with Parkinson's disease. Further studies exploring the multidimensional aspects of caregivers' quality of life are needed.

CLINICAL RELEVANCE

Rehabilitation nurses should identify caregivers at high risk in order to improve their quality of life. Nurses should assess education program needs and caregiving appraisal of caregivers of individuals with Parkinson's disease and develop a customized intervention program.

Parkinson's disease-related non-motor features as risk factors for post-operative delirium in spinal surgery

Background

The clinical features of postoperative delirium are similar to the core features of alpha synuclein-related cognitive disorders, such as Parkinson’s disease dementia (PDD) or dementia with Lewy bodies (DLB). Therefore, we hypothesized that the non-motor symptoms (NMSs) in Parkinson’s disease (PD), which precede the cardinal motor features of PD, are likely to be risk factors for developing postoperative delirium. We investigated the association between PD-related NMSs and postoperative delirium in old people undergoing elective spinal surgery.

Methods

This study was a prospective study. Participants were aged 65 years and older and scheduled to undergo elective spinal surgery. During the enrollment period, 338 individuals were screened, 104 participants were included in the analysis. We assessed eight easily-assessed and representative PD-related NMSs 1 day before the scheduled surgery using tests or questionnaires for each symptom. The presence of delirium was determined by using the short version of the Confusion Assessment Method (CAM).

Results

Fifteen (14.4%) of the 104 participants (age, 71.7 ± 4.7 years; men, 34.6%) met the CAM criteria for post-operative delirium. Multivariate logistic analysis showed that decreased olfactory function (odds ratio [OR] 0.63, 95% CI 0.44–0.91) and exhibiting rapid eye movement sleep behavior disorder (RBD, OR 1.45, 95% CI 1.09–1.93) were significantly independent predictors of postoperative delirium.

Conclusions

Our study shows that hyposmia and RBD are significantly independent risk factors for postoperative delirium in general elderly population. Considering that NMSs may represent burden of alpha synuclein deposit, we postulate that an underlying alpha synucleinopathy may correlates with postoperative delirium.

Significance

This study gives a novel insight for the risk factor of postoperative delirium.

Prevalence and risk factors for delirium diagnosis in patients followed in general practices in Germany

ABSTRACTBackground:The aim of this study is to identify the prevalence and risk factors of documented delirium in general practices in Germany.

METHODS

The present study includes 2,194 patients over the age of 65 years with delirium and 2,194 controls without delirium from a sample of 6,180,042 patients from 1,262 general practices. Multivariate logistic regression models were fitted with delirium as a dependent variable and other disorders and drugs as potential predictors.

RESULTS

A five-year-prevalence of 0.08% and an average of 0.7 (SD: 1.5) patients per practice per year were found. Among the study participants, 43.0% were men, and the mean age was 82.2 years (SD = 7.1 years). 24.2% of delirium patients and 10.3% of controls lived in nursing homes. Delirium was found to be positively associated with nursing home residence (OR: 1.69), dementia (OR = 3.45), epilepsy (OR = 2.16), stroke (OR = 1.80), Parkinson's disease (OR = 1.78), sleep disorder (OR = 1.64), renal insufficiency (OR = 1.57), fractures (OR = 1.56), and the prescription of benzodiazepines (OR = 1.62) and antiepileptics (OR = 1.53). Finally, the number of different drug classes prescribed within one year prior to the index date was positively associated with a risk of delirium. Compared to patients without medication therapy, the OR for delirium was 3.21 when more than four drug classes were prescribed.

CONCLUSIONS

In primary care, neuropsychiatric risk factors and polymedication were particularly important for the diagnosis of delirium compared to inpatient care. The methodological limitations of the analysis of data from routine care must be considered. Delirium is rarely diagnosed in primary care. Risk factors in primary care differ from those found in inpatient care. The reasons for this need to be further investigated.

Inpatient morbidity after spinal deformity surgery in patients with movement disorders

Background

To investigate the inpatient perioperative morbidity rate of patients with movement disorders (MD) after spinal deformity surgery.

Methods

The Nationwide Inpatient Sample database from 2002 to 2011 was queried to identify adult patients with MD who underwent spinal deformity surgery. Complication rates were compared between patients with MD and controls. A multiple logistic regression analysis was conducted to assess the effect of MD on outcome.

Results

A total of 365 patients with MD (3.3%) were identified among 11,043 patients undergoing surgery for spinal deformity. Patients with MD were on average 8 years older than the control group (67 vs. 59 years of age, P<0.001). The complication rate was 55.1% for patients with MD and 43.7% for patients without MD (P<0.001). The most common complication was acute post-hemorrhagic anemia, which occurred in 31.9% of all patients (41.6% in MD patients and 31.5% in the control group, P<0.001). Other complications that were more common in patients with MD included delirium (P<0.001), acute kidney injury (P=0.032), and pulmonary embolism (P=0.014). After controlling for patient age, sex, osteoporosis, complex procedures, fusion to the lumbosacral spine, use of bone morphogenetic protein, and use of blood transfusion, patients with MD were 1.3 times more likely to develop a complication compared to patients without MD [odds ratio (OR), 1.27; 95% confidence interval (CI), 1.02-1.59; P=0.032] on multiple logistic regression analysis. No significant difference in hospital stay was observed.

Conclusions

Patients with MD who undergo spinal deformity surgery may be at risk of higher rate of complications compared to patients without these disorders.

Management of Psychosis in Parkinson's Disease: Emphasizing Clinical Subtypes and Pathophysiological Mechanisms of the Condition

Investigation into neuropsychiatric symptoms in Parkinson's disease (PD) is sparse and current drug development is mainly focused on the motor aspect of PD. The tight association of psychosis with an impaired quality of life in PD, together with an important underreporting of this comorbid condition, contributes to its actual insufficient assessment and management. Furthermore, the withdrawal from access to readily available treatment interventions is unacceptable and has an impact on PD prognosis. Despite its impact, to date no standardized guidelines to the adequate management of PD psychosis are available and they are therefore highly needed. Readily available knowledge on distinct clinical features as well as early biomarkers of psychosis in PD justifies the potential for its timely diagnosis and for early intervention strategies. Also, its specific characterisation opens up the possibility of further understanding the underlying pathophysiological mechanisms giving rise to more targeted therapeutic developments in the nearer future. A literature review on the most recent knowledge with special focus on specific clinical subtypes and pathophysiological mechanisms will not only contribute to an up to date practical approach of this condition for the health care providers, but furthermore open up new ideas for research in the near future.

Psychosis in Parkinson's Disease: Epidemiology, Pathophysiology, and Management

Psychotic symptoms are common in Parkinson's disease (PD) and are associated with poorer quality of life and increased caregiver burden. PD psychosis is correlated with several factors, such as more advanced disease, cognitive impairment, depression, and sleep disorders. The underlying causes of psychosis in PD thus involve a complex interplay between exogenous (e.g., drugs, intercurrent illnesses) and endogenous (e.g., PD disease pathology) factors. Current theories of the pathophysiology of PD psychosis have come from several neuropathological and neuroimaging studies that implicate pathways involving visual processing and executive function, including temporo-limbic structures and neocortical gray matter with altered neurotransmitter functioning (e.g., dopamine, serotonin, and acetylcholine). Treatment of PD psychosis requires a step-wise process, including initial careful investigation of treatable triggering conditions and a comprehensive evaluation with adjustment of PD medications and/or initiation of specific antipsychotic therapies. Clozapine remains the only recommended drug for the treatment of PD psychosis; however, because of regular blood monitoring, quetiapine is usually first-line therapy, although less efficacious. Emerging studies have focused on agents involving other neurotransmitters, including the serotonin 5-HT2A receptor inverse agonist pimavanserin, cholinesterase inhibitors, and antidepressants and anxiolytics.

Delirium in Parkinson's Disease: A Cocktail Diagnosis

Mental disturbances have been described in patients with Parkinson's Disease (PD). Of these, the common conditions are delirium and psychosis. Delirium has been attributed to change of environment, especially hospital stay and infections; while psychosis is due to drugs like dopamine agonists. This is a case of a 75-year-old male, on levodopa therapy for PD, who presented with delirium and ended up with a cocktail diagnosis: Cryptococcal meningitis, Hashimoto's Encephalopathy (HE), Urinary tract infection with acute renal failure, Uremic encephalopathy and Levodopa induced psychosis. This case report, therefore, highlights the need to look for other causes of delirium in a patient with PD who is on levodopa therapy.

Pharmacotherapies for Parkinson's disease symptoms related to cholinergic degeneration

INTRODUCTION

Dopamine depletion is one of the most important features of Parkinson's Disease (PD). However, insufficient response to dopaminergic replacement therapy suggests the involvement of other neurotransmitter systems in the pathophysiology of PD. Cholinergic degeneration contributes to gait impairments, cognitive impairment, psychosis, and REM-sleep disturbances, among other symptoms. Areas covered: In this review, we explore the idea that enhancing cholinergic tone by pharmacological or neurosurgical procedures could be a first-line therapeutic strategy for the treatment of symptoms derived from cholinergic degeneration in PD. Expert opinion: Rivastigmine, a drug that increases cholinergic tone by inhibiting the enzyme cholinesterase, is effective for dementia, whereas the use of Donepezil is still in the realm of investigation. Interesting results suggest the efficacy of these drugs in the treatment of gait dysfunction. Evidence on the clinical effects of these drugs for psychosis and REM-sleep disturbances is still weak. Stimulation of the pedunculo-pontine tegmental nuclei (which provide cholinergic innervation to the brain stem and subcortical nuclei) has also been used with some success for the treatment of gait dysfunction. Anticholinergic drugs should be used with caution in PD, as they may aggravate cholinergic symptoms. Notwithstanding, in some patients they might help control parkinsonian motor symptoms.

Deficits in cholinergic neurotransmission and their clinical correlates in Parkinson's disease

In view of its ability to explain the most frequent motor symptoms of Parkinson’s Disease (PD), degeneration of dopaminergic neurons has been considered one of the disease’s main pathophysiological features. Several studies have shown that neurodegeneration also affects noradrenergic, serotoninergic, cholinergic and other monoaminergic neuronal populations. In this work, the characteristics of cholinergic deficits in PD and their clinical correlates are reviewed. Important neurophysiological processes at the root of several motor and cognitive functions remit to cholinergic neurotransmission at the synaptic, pathway, and circuital levels. The bulk of evidence highlights the link between cholinergic alterations and PD motor symptoms, gait dysfunction, levodopa-induced dyskinesias, cognitive deterioration, psychosis, sleep abnormalities, autonomic dysfunction, and altered olfactory function. The pathophysiology of these symptoms is related to alteration of the cholinergic tone in the striatum and/or to degeneration of cholinergic nuclei, most importantly the nucleus basalis magnocellularis and the pedunculopontine nucleus. Several results suggest the clinical usefulness of antimuscarinic drugs for treating PD motor symptoms and of inhibitors of the enzyme acetylcholinesterase for the treatment of dementia. Data also suggest that these inhibitors and pedunculopontine nucleus deep-brain stimulation might also be effective in preventing falls. Finally, several drugs acting on nicotinic receptors have proved efficacious for treating levodopa-induced dyskinesias and cognitive impairment and as neuroprotective agents in PD animal models. Results in human patients are still lacking.