Anxiety in Parkinson's disease: a critical review of experimental and clinical studies

Effects of STN-DBS on cognition and mood in young-onset Parkinson's disease: a two-year follow-up

Background

The effects of subthalamic nucleus deep brain stimulation (STN-DBS) on the cognition and mood of patients with PD are still not uniformly concluded, and young-onset Parkinson's disease (YOPD) is even less explored.

Objective

To observe the effectiveness of STN-DBS on the cognition and mood of YOPD patients.

Methods

A total of 27 subjects, with a mean age at onset of 39.48 ± 6.24 and age at surgery for STN-DBS of 48.44 ± 4.85, were followed up preoperatively and for 2 years postoperatively. Using the Unified Parkinson disease rating scale (UPDRS), H&Y(Hoehn and Yahr stage), 39-Item Parkinson's Disease Questionnaire (PDQ-39), Mini-mental state examination (MMSE), Montreal Cognitive Assessment (MoCA), Hamilton depression scale (HAMD), Hamilton anxiety scale (HAMA) to assess motor, cognition, and mood.

Results

At the 2-year follow-up after STN-DBS, YOPD patients showed significant improvements in motor and quality of life (UPDRS III: p < 0.001, PDQ-39: p < 0.001); overall cognition was not significantly different from preoperative (MMSE: p = 0.275, MoCA: p = 0.913), although language function was significantly impaired compared to preoperative (MMSE: p = 0.004, MoCA: p = 0.009); depression and anxiety symptoms also improved significantly (HAMD: p < 0.001, HAMA: p < 0.001) and the depression score correlated significantly with motor (preoperative: r = 0.493, p = 0.009), disease duration (preoperative: r = 0.519, p = 0.006; postoperative: r = 0.406, p = 0.036) and H&Y (preoperative: r = 0.430, p = 0.025; postoperative: r = 0.387, p = 0.046); total anxiety scores were also significantly correlated with motor (preoperative: r = 0.553, p = 0.003; postoperative: r = 0.444, p = 0.020), disease duration (preoperative: r = 0.417, p = 0.031), PDQ-39 (preoperative: r = 0.464, p = 0.015) and H&Y (preoperative: r = 0.440, p = 0.022; postoperative: r = 0.526, p = 0.005).

Conclusion

STN-DBS is a safe and effective treatment for YOPD. The mood improved significantly, and overall cognition was not impaired, were only verbal fluency decreased but did not affect the improvement in quality of life.

Therapeutic Viewpoint on Rat Models of Locomotion Abnormalities and Neurobiological Indicators in Parkinson's Disease

BACKGROUND

Locomotion problems in Parkinson's syndrome are still a research and treatment difficulty. With the recent introduction of brain stimulation or neuromodulation equipment that is sufficient to monitor activity in the brain using electrodes placed on the scalp, new locomotion investigations in patients having the capacity to move freely have sprung up.

OBJECTIVE

This study aimed to find rat models and locomotion-connected neuronal indicators and use them all over a closed-loop system to enhance the future and present treatment options available for Parkinson's disease.

METHODS

Various publications on locomotor abnormalities, Parkinson's disease, animal models, and other topics have been searched using several search engines, such as Google Scholar, Web of Science, Research Gate, and PubMed.

RESULTS

Based on the literature, we can conclude that animal models are used for further investigating the locomotion connectivity deficiencies of many biological measuring devices and attempting to address unanswered concerns from clinical and non-clinical research. However, translational validity is required for rat models to contribute to the improvement of upcoming neurostimulation-based medicines. This review discusses the most successful methods for modelling Parkinson's locomotion in rats.

CONCLUSION

This review article has examined how scientific clinical experiments lead to localised central nervous system injuries in rats, as well as how the associated motor deficits and connection oscillations reflect this. This evolutionary process of therapeutic interventions may help to improve locomotion- based treatment and management of Parkinson's syndrome in the upcoming years.

A Systematic Review of Psychotherapy Approaches for Anxiety in Parkinson's Disease

OBJECTIVES

Anxiety is common in Parkinson's disease (PD), negatively impacting daily functioning and quality of life in PD patients and their families. This systematic review evaluates the effectiveness of different psychotherapeutic approaches for reducing anxiety in PD and provides recommendations for clinical practise.

METHODS

Following PRISMA guidelines, 36 studies were included and risk of bias was evaluated.

RESULTS

We identified cognitive behavioral therapy (CBT), mindfulness-based therapies, acceptance and commitment therapy, and psychodrama psychotherapies. There is good evidence-base for anxiety reduction using CBT approaches, but with mixed results for mindfulness-based therapies. Other therapeutic approaches were under researched. Most randomized control trials examined anxiety as a secondary measure. There was a paucity of interventions for anxiety subtypes. Secondarily, studies revealed the consistent exclusion of PD patients with cognitive concerns, an importance of care partner involvement, and a growing interest in remote delivery of psychotherapy interventions.

CONCLUSIONS

Person-centered anxiety interventions tailored for PD patients, including those with cognitive concerns, and trials exploring modalities other than CBT, warrant future investigations.

CLINICAL IMPLICATIONS

Practitioners should consider PD-specific anxiety symptoms and cognitive concerns when treating anxiety. Key distinctions between therapeutic modalities, therapy settings and delivery methods should guide treatment planning.

Inhibition of calcium-stimulated adenylyl cyclase subtype 1 (AC1) for the treatment of pain and anxiety symptoms in Parkinson's disease mice model

Pain and anxiety are two common and undertreated non-motor symptoms in Parkinson's disease (PD), which affect the life quality of PD patients, and the underlying mechanisms remain unclear. As an important subtype of adenylyl cyclases (ACs), adenylyl cyclase subtype 1 (AC1) is critical for the induction of cortical long-term potentiation (LTP) and injury induced synaptic potentiation in the cortical areas including anterior cingulate cortex (ACC) and insular cortex (IC). Genetic deletion of AC1 or pharmacological inhibition of AC1 improved chronic pain and anxiety in different animal models. In this study, we proved the motor deficit, pain and anxiety symptoms of PD in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice model. As a lead candidate AC1 inhibitor, oral administration (1 dose and seven doses) of NB001 (20 and 40 mg/kg) showed significant analgesic effect in MPTP-treated mice, and the anxiety behavior was also reduced (40 mg/kg). By using genetic knockout mice, we found that AC1 knockout mice showed reduced pain and anxiety symptoms after MPTP administration, but not AC8 knockout mice. In summary, genetic deletion of AC1 or pharmacological inhibition of AC1 improved pain and anxiety symptoms in PD model mice, but didn't affect motor function. These results suggest that NB001 is a potential drug for the treatment of pain and anxiety symptoms in PD patients by inhibiting AC1 target.

Caffeine alleviates anxiety-like behavior and brainstem lesions in a rotenone-induced rat model of Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms. In 2016, approximately 6.1 million individuals were affected by PD, with 211,296 deaths attributed to the disease. The understanding of PD initially came from the observation of dopaminergic system alterations in a specific region of the brainstem, indicating that the core motor and non-motor features of PD are closely associated with brainstem dysfunction. The primary treatment approach for PD revolves around dopamine replacement, as many of the symptoms are responsive to this therapeutic intervention. However, long-term administration of this approach is linked to several complications, and a definitive gold-standard therapy for PD is yet to be identified. The pharmacological management of PD has been challenging and inconsistent, mainly due to the unclear underlying cause of the disease. This study aims to evaluate the effects of caffeine on the brainstem of rats with PD induced by rotenone.

METHODOLOGY

Fifty adult male Wistar rats weighing between 150 and 200 g were used in this study. The rats were randomly divided into five groups of ten rats each: Vehicle Group, Rotenone-only treated Group (rotenone only treated with 3 mg/kg, intraperitoneal administration [IP]), Preventive Group (caffeine 30 mg/kg + rotenone 3 mg/kg, IP), Curative Group (rotenone 3 mg/kg + caffeine 30 mg/kg, IP), and Caffeine only treated Group (caffeine only treated with 30 mg/kg, IP). The animals underwent neurobehavioral assessments, followed by sacrifice. The brains were then excised, weighed, and processed histologically. Appropriate brain sections were taken and processed. Photomicrographs were obtained, morphometric and statistical analysis was performed using an Omax LED digital RESULTS: The results demonstrated a significant (p < 0.05) reduction in body weight and relative brain weight, which were increased by caffeine treatments. Rotenone administration led to histological changes similar to those observed in PD, including neuronal structural derangement, degenerated nerve fibers, loss of myelinated neurons, and Nissl substance, as well as downregulation in the expressions of NRF2 and TH in the midbrain. However, these pathological features were counteracted or ameliorated by caffeine treatment.

CONCLUSION

Our study contributes additional evidence to the growing body of research supporting the therapeutic potential of caffeine in Parkinson's disease (PD). The results underscore the neuroprotective properties of caffeine and its capacity to mitigate oxidative stress by modulating TH (tyrosine hydroxylase) and cytoplasmic NRF2 (nuclear factor erythroid 2-related factor 2) in the mesencephalon. These findings suggest that caffeine holds promise as a viable treatment option for PD.

Functional Connectivity and Anxiety Improvement After Subthalamic Nucleus Deep Brain Stimulation in Parkinson's Disease

Background

Anxiety is one of the most common and disturbing non-motor symptoms of Parkinson's disease (PD). However, few studies have explored the relationship between functional connectivity (FC) and the rate of anxiety improvement after subthalamic nucleus deep brain stimulation (STN-DBS). Therefore, in this study, we aimed to explore the correlation between FC and the rate of anxiety improvement in patients with PD who underwent STN-DBS.

Methods

The resting-state functional magnetic resonance imaging (rs-fMRI) data of 62 patients with anxious PD (aPD), 68 patients with PD without anxiety (naPD), and 64 healthy controls (HCs) were analyzed according to FC. Intergroup comparison and correlation analyses of anxiety improvement rates were performed.

Results

The HC, aPD and naPD groups of zFCs were then used for the ANOVA test, and the results were FDR-corrected. There were 24 significant differences in FCs between the three groups. Post tests were conducted between groups found that 15 significantly different FCs were observed between the naPD and aPD groups. In addition, the two FCs in patients with aPD were significantly correlated with the rate of improvement in anxiety.

Conclusion

We found that the two FCs in patients with aPD (olfactory cortex and inferior frontal gyrus [IFG] pars orbitalis; inferior temporal gyrus and posterior orbital gyrus) were significantly correlated with the rate of improvement in anxiety. Our study may help us understand the underlying mechanisms by which STN-DBS improves anxiety in PD patients and identify more effective treatment strategies.

Quantification of Non-Motor Symptoms in Parkinsonian Cynomolgus Monkeys

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative disorder that features motor and non-motor deficits. The use of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopamine neuron degeneration has been widely practiced to produce reliable animal models of PD. However, most previous preclinical studies focused on motor dysfunction, and few non-motor symptoms were evaluated. Thus far, there is a lack of comprehensive investigations of the non-motor symptoms in animal models.

OBJECTIVES

In this study, we aim to use a battery of behavioral methods to evaluate non-motor symptoms in MPTP-induced non-human primate PD models.

METHODS

Cognitive function, sleep, and psychiatric behaviors were evaluated in MPTP-treated cynomolgus monkeys. The tests consisted of a delayed matching-to-sample (DMTS) task, the use of a physical activity monitor (PAM), an apathy feeding task (AFT), the human intruder test (HIT), novel fruit test (NFT), and predator confrontation test (PCT). In addition, we tested whether the dopamine receptor agonist pramipexole (PPX) can improve these non-motor symptoms.

RESULTS

The present results show that the MPTP-treated monkeys exhibited cognitive deficits, abnormal sleep, and anxiety-like behaviors when compared to the control monkeys. These symptoms were relieved partially by PPX.

CONCLUSIONS

These results suggest that MPTP-induced PD monkeys displayed non-motor symptoms that were similar to those found in PD patients. PPX treatment showed moderate therapeutic effects on these non-motor symptoms. This battery of behavioral tests may provide a valuable model for future preclinical research.

The α1 and γ2 subunit-containing GABAA receptor-mediated inhibitory transmission in the anteroventral bed nucleus of stria terminalis is involved in the regulation of anxiety in rats with substantia nigra lesions

The anteroventral bed nucleus of the stria terminalis (avBNST) is widely acknowledged as a key brain structure that regulates negative emotional states, such as anxiety. At present, it is still unclear whether GABA_A receptor-mediated inhibitory transmission in the avBNST is involved in Parkinson's disease (PD)-related anxiety. In this study, unilateral 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra pars compacta (SNc) in rats induced anxiety-like behaviors, increased GABA synthesis and release, and upregulated expression of GABA_A receptor subunits in the avBNST, as well as decreased level of dopamine (DA) in the basolateral amygdala (BLA). In both sham and 6-OHDA rats, intra-avBNST injection of GABA_A receptor agonist muscimol induced the following changes: (i) anxiolytic-like responses, (ii) inhibition of the firing activity of GABAergic neurons in the avBNST, (iii) excitation of dopaminergic neurons in the ventral tegmental area (VTA) and serotonergic neurons in the dorsal raphe nucleus (DRN), and (iv) increase of DA and 5-HT release in the BLA, whereas antagonist bicuculline induced the opposite effects. Collectively, these findings suggest that degeneration of the nigrostriatal pathway enhances GABA_A receptor-mediated inhibitory transmission in the avBNST, which is involved in PD-related anxiety. Further, activation and blockade of avBNST GABA_A receptors affect the firing activity of VTA dopaminergic and DRN serotonergic neurons, and then change release of BLA DA and 5-HT, thereby regulating anxiety-like behaviors.

The experience of Anxiety for people with Parkinson's disease

Anxiety is a common non-motor symptom of Parkinson's disease (PD) associated with increased disability and reduced quality of life. However, anxiety is poorly understood, underdiagnosed, and undertreated. To date, little research has explored how anxiety is experienced by patients themselves. This study explored the experience of anxiety for people with Parkinson's (PWP) to inform future research and interventions. Semi-structured interviews with 22 PWP (aged 43-80, 50% female) were conducted and analysed using inductive thematic analysis. Four main themes were extracted: conceptualising anxiety; anxiety and the body; anxiety and social identity; and coping with anxiety. Sub-themes revealed inconsistent perceptions: anxiety was in body and mind, part of disease and human nature, part of self-identity and a threat to it. The symptoms described were diverse. Many perceived their anxiety as more incapacitating than motor symptoms or capable of amplifying them, and described that anxiety restricted their lifestyle. All perceived anxiety as connected to PD, and ultimately persistent: dominant aspirations were coping and acceptance rather than cures, with medications strongly resisted. Findings highlight the complexity and high importance of anxiety for PWP. Implications for therapeutic approaches are discussed.

Mood disturbances in Parkinson's disease: From prodromal origins to application of animal models

Parkinson's disease (PD) is a complex illness with a constellation of environmental insults and genetic vulnerabilities being implicated. Strikingly, many studies only focus on the cardinal motor symptoms of the disease and fail to appreciate the major non-motor features which typically occur early in the disease process and are debilitating. Common comorbid psychiatric features, notably clinical depression, as well as anxiety and sleep disorders are thought to emerge before the onset of prominent motor deficits. In this review, we will delve into the prodromal stage of PD and how early neuropsychiatric pathology might unfold, followed by later motor disturbances. It is also of interest to discuss how animal models of PD capture the complexity of the illness, including depressive-like characteristics along with motor impairment. It remains to be determined how the underlying PD disease processes contributes to such comorbidity. But some of the environmental toxicants and microbial pathogens implicated in PD might instigate pro-inflammatory effects favoring α-synuclein accumulation and damage to brainstem neurons fueling the evolution of mood disturbances. We posit that comprehensive animal-based research approaches are needed to capture the complexity and time-dependent nature of the primary and co-morbid symptoms. This will allow for the possibility of early intervention with more novel and targeted treatments that fit with not only individual patient variability, but also with changes that occur over time with the evolution of the disease.

Tyrosinase-induced neuromelanin accumulation triggers rapid dysregulation and degeneration of the mouse locus coeruleus

Motor symptoms in Parkinson's disease (PD) are caused by degeneration of dopamine (DA) neurons of the substantia nigra (SN), while early non-motor symptoms such as anxiety and sleep disturbances are likely mediated by dysfunction of locus coeruleus (LC) norepinephrine (NE) neurons. The LC develops α-synuclein pathology prior to SN DA neurons in PD, and later undergoes degeneration, but the mechanisms responsible for its vulnerability are unknown. The SN and LC are the only structures in the brain that produces appreciable amounts of neuromelanin (NM), a dark cytoplasmic pigment. It has been proposed that NM initially plays a protective role by sequestering toxic catecholamine metabolites and heavy metals, but may become harmful during aging and PD as they overwhelm cellular machinery and are released during neurodegeneration. Rodents do not naturally produce NM, limiting the study of causal relationships between NM and PD-associated LC pathology. Adapting a viral-mediated approach for expression of human tyrosinase, the enzyme responsible for peripheral melanin production, we successfully promoted pigmentation in mouse LC neurons that recapitulates key features of endogenous NM found in primates, including eumelanin and pheomelanin, lipid droplets, and a double-membrane encasement. Pigment expression results in mild neurodegeneration, reduced NE levels, transcriptional changes, and novelty-induced anxiety phenotypes as early as 1-week post-injection. By 6-weeks, NM accumulation is associated with severe LC neurodegeneration and a robust neuroinflammatory response. These phenotypes are reminiscent of LC dysfunction in PD, validating this model for studying the consequences of pigment accumulation in the LC as it relates to neurodegenerative disease.

Evaluation of the therapeutic potential of cerebrolysin and/or lithium in the male Wistar rat model of Parkinson's disease induced by reserpine

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease worldwide and represents a challenge for clinicians. The present study aims to investigate the effects of cerebrolysin and/or lithium on the behavioral, neurochemical and histopathological alterations induced by reserpine as a model of PD. The rats were divided into control and reserpine-induced PD model groups. The model animals were further divided into four subgroups: rat PD model, rat PD model treated with cerebrolysin, rat PD model treated with lithium and rat PD model treated with a combination of cerebrolysin and lithium. Treatment with cerebrolysin and/or lithium ameliorated most of the alterations in oxidative stress parameters, acetylcholinesterase and monoamines in the striatum and midbrain of reserpine-induced PD model. It also ameliorated the changes in nuclear factor-kappa and improved the histopathological picture induced by reserpine. It could be suggested that cerebrolysin and/or lithium showed promising therapeutic potential against the variations induced in the reserpine model of PD. However, the ameliorating effects of lithium on the neurochemical, histopathological and behavioral alterations induced by reserpine were more prominent than those of cerebrolysin alone or combined with lithium. It can be concluded that the antioxidant and anti-inflammatory effects of both drugs played a significant role in their therapeutic potency.

The impact of iron deposition on the fear circuit of the brain in patients with Parkinson's disease and anxiety

Objective

Anxiety is one of the most common psychiatric symptoms of Parkinson's disease (PD), and brain iron deposition is considered to be one of the pathological mechanisms of PD. The objective of this study was to explore alterations in brain iron deposition in PD patients with anxiety compared to PD patients without anxiety, especially in the fear circuit.

Methods

Sixteen PD patients with anxiety, 23 PD patients without anxiety, and 26 healthy elderly controls were enrolled prospectively. All subjects underwent neuropsychological assessments and brain magnetic resonance imaging (MRI) examinations. Voxel-based morphometry (VBM) was used to study morphological brain differences between the groups. Quantitative susceptibility mapping (QSM), an MRI technique capable of quantifying susceptibility changes in brain tissue, was used to compare susceptibility changes in the whole brain among the three groups. The correlations between brain susceptibility changes and anxiety scores quantified using the Hamilton Anxiety Rating Scale (HAMA) were compared and analyzed.

Results

PD patients with anxiety had a longer duration of PD and higher HAMA scores than PD patients without anxiety. No morphological brain differences were observed between the groups. In contrast, voxel-based and ROI-based QSM analyses showed that PD patients with anxiety had significantly increased QSM values in the medial prefrontal cortex, anterior cingulate cortex, hippocampus, precuneus, and angular cortex. Furthermore, the QSM values of some of these brain regions were positively correlated with the HAMA scores (medial prefrontal cortex: r = 0.255, p = 0.04; anterior cingulate cortex: r = 0.381, p < 0.01; hippocampus: r = 0.496, p < 0.01).

Conclusion

Our findings support the idea that anxiety in PD is associated with iron burden in the brain fear circuit, providing a possible new approach to explaining the potential neural mechanism of anxiety in PD.

Therapeutic Approaches to Non-Motor Symptoms of Parkinson's Disease: A Current Update on Preclinical Evidence

Despite being classified as a movement disorder, Parkinson's disease (PD) is characterized by a wide range of non-motor symptoms that significantly affect the patients' quality of life. However, clear evidence-based therapy recommendations for non-motor symptoms of PD are uncommon. Animal models of PD have previously been shown to be useful for advancing the knowledge and treatment of motor symptoms. However, these models may provide insight into and assess therapies for non-motor symptoms in PD. This paper highlights non-motor symptoms in preclinical models of PD and the current position regarding preclinical therapeutic approaches for these non-motor symptoms. This information may be relevant for designing future preclinical investigations of therapies for nonmotor symptoms in PD.

Protective Effects of Currants (Vitis vinifera) on Corticolimbic Serotoninergic Alterations and Anxiety-like Comorbidity in a Rat Model of Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the loss of nigral dopaminergic neurons. Increasing evidence supports that PD is not simply a motor disorder but a systemic disease leading to motor and non-motor symptoms, including memory loss and neuropsychiatric conditions, with poor management of the non-motor deficits by the existing dopaminergic medication. Oxidative stress is considered a contributing factor for nigrostriatal degeneration, while antioxidant/anti-inflammatory properties of natural phyto-polyphenols have been suggested to have beneficial effects. The present study aimed to determine the contribution of monoaminergic neurotransmission on the anxiety-like phenotype in a rat rotenone PD model and evaluate the possible neuroprotective effects of black Corinthian currant, Vitis vinifera, consisting of antioxidant polyphenols. Rotenone-treated rats showed anxiety-like behavior and exploratory deficits, accompanied by changes in 5-HT, SERT and β₂-ARs expression in the prefrontal cortices, hippocampus and basolateral amygdala. Importantly, the motor and non-motor behavior, as well as 5-HT, SERT and β₂-ARs expression patterns of the PD-like phenotype were partially recovered by a supplementary diet with currants. Overall, our results suggest that the neuroprotective effects of Corinthian currants in rotenone-induced anxiety-like behavior may be mediated via corticolimbic serotonergic transmission.

Serotonin and dopamine transporter availability in social anxiety disorder after combined treatment with escitalopram and cognitive-behavioral therapy

Selective serotonin reuptake inhibitors (SSRIs) and internet-based cognitive behavioral therapy (ICBT) are recommended treatments of social anxiety disorder (SAD), and often combined, but their effects on monoaminergic signaling are not well understood. In this multi-tracer positron emission tomography (PET) study, 24 patients with SAD were randomized to treatment with escitalopram+ICBT or placebo+ICBT under double-blind conditions. Before and after 9 weeks of treatment, patients were examined with positron emission tomography and the radioligands [¹¹C]DASB and [¹¹C]PE2I, probing the serotonin (SERT) and dopamine (DAT) transporter proteins respectively. Both treatment combinations resulted in significant improvement as measured by the Liebowitz Social Anxiety Scale (LSAS). At baseline, SERT-DAT co-expression was high and, in the putamen and thalamus, co-expression showed positive associations with symptom severity. SERT-DAT co-expression was also predictive of treatment success, but predictor-outcome associations differed in direction between the treatments. After treatment, average SERT occupancy in the SSRI + ICBT group was >80%, with positive associations between symptom improvement and occupancy in the nucleus accumbens, putamen and anterior cingulate cortex. Following placebo+ICBT, SERT binding increased in the raphe nuclei. DAT binding increased in both groups in limbic and striatal areas, but relations with symptom improvement differed, being negative for SSRI + ICBT and positive for placebo + ICBT. Thus, serotonin-dopamine transporter co-expression exerts influence on symptom severity and remission rate in the treatment of social anxiety disorder. However, the monoamine transporters are modulated in dissimilar ways when cognitive-behavioral treatment is given concomitantly with either SSRI-medication or pill placebo.

Anxiety symptoms in older Chinese adults in primary care settings: Prevalence and correlates

Background

Integrating mental health services into primary care is a potentially cost-effective way to decrease the treatment gap for anxiety in older adults but data on the epidemiology of anxiety symptoms in older Chinese adults in primary care settings have been very limited. This study investigated the prevalence and correlates of anxiety symptoms in Chinese older primary care patients.

Methods

A total of 753 older primary care patients (≥65 years) were consecutively recruited from 13 primary care clinics in Wuhan, China, and interviewed with the validated Chinese version of the short form of the Geriatric Anxiety Inventory (GAI-SF).

Results

The prevalence of anxiety symptoms (GAI-SF ≥ 3) in older primary care patients was 21.1%. Statistically significant correlates of anxiety symptoms were female sex (vs. male, OR = 1.85, P = 0.002), poor economic status (vs. good, OR = 2.31, P = 0.013), fair and poor family relationship (vs. good, OR = 1.85, P = 0.006), hypertension (OR = 2.01, P < 0.001), chronic gastric ulcer (OR = 6.82, P < 0.001), and Parkinson's disease (OR = 7.83, P = 0.031).

Conclusions

Anxiety symptoms are prevalent among older adults attending primary care clinics. Efforts for preventing or reducing anxiety symptoms in older primary care patients may be more useful to target those who are women, have poor financial status, don't have a good family relationship, suffer from hypertension, have chronic gastric ulcer, and suffer from Parkinson's disease.

After 55 Years of Neurorehabilitation, What Is the Plan?

Neurological disorders often cause severe long-term disabilities with substantial activity limitations and participation restrictions such as community integration, family functioning, employment, social interaction and participation. Increasing understanding of brain functioning has opened new perspectives for more integrative interventions, boosting the intrinsic central nervous system neuroplastic capabilities in order to achieve efficient behavioral restitution. Neurorehabilitation must take into account the many aspects of the individual through a comprehensive analysis of actual and potential cognitive, behavioral, emotional and physical skills, while increasing awareness and understanding of the new self of the person being dealt with. The exclusive adoption by the rehabilitator of objective functional measures often overlooks the values and goals of the disabled person. Indeed, each individual has their own rhythm, unique life history and personality construct. In this challenging context, it is essential to deepen the assessment through subjective measures, which more adequately reflect the patient’s perspective in order to shape genuinely tailored instead of standardized neurorehabilitation approaches. In this overly complex panorama, where confounding and prognostic factors also strongly influence potential functional recovery, the healthcare community needs to rethink neurorehabilitation formats.

Modeling Parkinson's disease-related symptoms in alpha-synuclein overexpressing mice

BACKGROUND

Intracellular deposition of alpha-synuclein (α-syn) as Lewy bodies and Lewy neurites is a central event in the pathogenesis of Parkinson's disease (PD) and other α-synucleinopathies. Transgenic mouse models overexpressing human α-syn, are useful research tools in preclinical studies of pathogenetic mechanisms. Such mice develop α-syn inclusions as well as neurodegeneration with a topographical distribution that varies depending on the choice of promoter and which form of α-syn that is overexpressed. Moreover, they display motor symptoms and cognitive disturbances that to some extent resemble the human conditions.

PURPOSE

One of the main motives for assessing behavior in these mouse models is to evaluate the potential of new treatment strategies, including their impact on motor and cognitive symptoms. However, due to a high within-group variability with respect to such features, the behavioral studies need to be applied with caution. In this review, we discuss how to make appropriate choices in the experimental design and which tests that are most suitable for the evaluation of PD-related symptoms in such studies.

METHODS

We have evaluated published results on two selected transgenic mouse models overexpressing wild type (L61) and mutated (A30P) α-syn in the context of their validity and utility for different types of behavioral studies.

CONCLUSIONS

By applying appropriate behavioral tests, α-syn transgenic mouse models provide an appropriate experimental platform for studies of symptoms related to PD and other α-synucleinopathies.

Vortioxetine ameliorates motor and cognitive impairments in the rotenone-induced Parkinson's disease via targeting TLR-2 mediated neuroinflammation

Parkinson's disease (PD) is characterized by motor and non-motor symptoms associated with dopaminergic and non-dopaminergic injury. Vortioxetine is a multimodal serotonergic antidepressant with potential procognitive effects. This study aimed to explore the effects of vortioxetine on motor functions, spatial learning and memory, and depression-like behavior in the rotenone-induced rat model of PD. Male Sprague-Dawley rats were daily administered with the rotenone (2 mg·kg^-1, s.c.) and/or vortioxetine (10 mg·kg^-1, s.c.) for 28 days. Motor functions (rotarod, catalepsy, open-field), depression-like behaviors (sucrose preference test), anxiety (elevated plus maze), and spatial learning and memory abilities (novel object recognition and Morris water maze) were evaluated in behavioral tests. Then immunohistochemical, neurochemical, and biochemical analysis on specific brain areas were performed. Vortioxetine treatment markedly reduced rotenone-induced neurodegeneration, improved motor and cognitive dysfunction, decreased depression-like behaviors without affecting anxiety-like parameters. Vortioxetine also restored the impaired inflammatory response and affected neurotransmitter levels in brain tissues. Interestingly, vortioxetine was thought to trigger a sort of dysfunction in basal ganglia as evidenced by increased Toll-like receptor-2 (TLR-2) and decreased TH immunoreactivity only in substantia nigra tissue of PD rats compared to the control group. The present study indicates that vortioxetine has beneficial effects on motor dysfunction as well as cognitive impairment associated with neurodegeneration in the rotenone-induced PD model. Possible mechanisms underlying these beneficial effects cover TLR-2 inhibition and neurochemical restoration of vortioxetine.

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.

Prevalence of Pseudobulbar Affect (PBA) in Parkinson's Disease: An Underrecognized Patient Burden

Objective

Pseudobulbar affect (PBA) is a neurological condition characterized by emotional lability and a discrepancy between the patient’s emotional expression and emotional experience. These uncontrollable episodes cause distress in social situations resulting in embarrassment and social withdrawal. The most comprehensive study to date estimated that 26% of Parkinson’s disease (PD) patients screened positive for PBA symptoms via the validated Center for Neurologic Study-Lability Scale (CNS-LS) screening tool. We hypothesize that the prevalence of this disabling syndrome is higher than reported, often being labeled as depression.

Methods

One hundred patients were enrolled in the study and screened with a CNS-LS tool, all of whom were diagnosed with PD by a fellowship-trained movement disorder specialist. Patients were also asked about previous diagnosis of depression, current antidepressant medication use, and history of PBA diagnosis and treatment.

Results

The percentage of PD patients (n = 100) with PBA symptoms as defined by a CNS-LS score ≥13 was 41% (n = 41) and by a CNS-LS score ≥17 was 21.0% (n = 21). In our sample, 38.0% of patients (n = 38) had a previous clinical diagnosis of depression and 25.0% (n = 25) were currently undergoing treatment for their depression. There was a significant association between previous depression diagnosis, current antidepressant use, and higher CNS-LS scores (p < 0.001).

Conclusion

Using either of the CNS-LS score cutoffs, a significant proportion of the PD population in our sample displayed symptoms of PBA. We also found an association between previous diagnosis of depression and higher CNS-LS scores as well as between antidepressant use and higher CNS-LS scores. This suggests both a higher prevalence than prior studies showed as well as frequent misdiagnosis or co-diagnosis with depression.

Six-Year Follow-Up of Dysphagia in Patients with Parkinson's Disease

The current study sought to examine longitudinal changes of dysphagia in Parkinson's disease, identify predictors of dysphagia aggravation and elucidate the influence of dysphagia on other symptoms in Parkinson's disease patients. Forty-eight patients with Parkinson's disease were enrolled. All patients underwent videofluoroscopic study of swallowing evaluation and a battery of neuropsychological assessments at baseline in 2014 and at follow-up in 2020. We used t-tests or Wilcoxon tests for comparative analysis between patients with/without dysphagia and comparative analysis of longitudinal data. We used Spearman's correlation analysis to examine predictors of dysphagia aggravation, and the Wilcoxon test to compare neuropsychological aggravation between patients with/without dysphagia at baseline. Swallowing function, cognitive function, depression, anxiety, and quality of life were aggravated at follow-up. Dysphagia prevalence increased from 27.08 at baseline to 39.58% at follow-up. Spearman's correlation results showed that dysphagia was more likely to become aggravated in male patients compared with female patients (P = 0.0049). Cognitive impairment at baseline was significantly related to dysphagia aggravation (P = 0.042). Patients with dysphagia at baseline exhibited a significantly greater increase in anxiety scores than patients without dysphagia at baseline (P = 0.021). The results revealed that male sex and cognitive impairment predicted worsening dysphagia in Parkinson's disease patients, and suggested that dysphagia may have a negative impact on anxiety in Parkinson's disease patients. The results highlight the importance of swallowing function screening and necessary instrumental checks, such as videofluoroscopic study of swallowing, in Parkinson's disease patients.

Lesions of the lateral habenula produce anxiolytic effects in a rat model of Parkinson's disease

Objective: This study was designed to investigate the effects of lateral habenula (LHb) lesion on anxiety-like behaviors in parkinsonian rats.Methods: Anxiety-like behaviors were assessed by the open field and elevated plus maze (EPM) tests in control, medial forebrain bundle (MFB)-lesioned, MFB- and LHb-lesioned and MFB-lesioned and LHb sham-lesioned rats, respectively. The levels of extracellular dopamine (DA), serotonin (5-HT) and noradrenaline (NA) in the basolateral amygdala (BLA) were measured by in vivo microdialysis and neurochemistry.Results: Compared to control rats, MFB lesions in rats decreased the percentage of time spent in the central area in the open field test and the percentages of open arm time and open arm entries in the EPM test, indicating the induction of anxiety-like behaviors, and this lesion also decreased the level of extracellular DA in the BLA. Further, rats in the MFB + LHb lesion group showed increased percentage of time spent in the central area and the percentages of open arm time and open arm entries compared to rats in the MFB lesion group, suggesting anxiolytic effects after lesioning the LHb. Neurochemical results found that lesions of the LHb increased the levels of extracellular DA and 5-HT in the BLA in the MFB and LHb lesion groups, whereas NA level was not altered.Discussion: These findings suggest that depletion of DA plays an important role in anxiety-like behaviors, and lesions of the LHb produce anxiolytic responses in MFB-lesioned rats, which are related to increased levels of extracellular DA and 5-HT in the BLA.

Cortical Serotonergic and Catecholaminergic Denervation in MPTP-Treated Parkinsonian Monkeys

Decreased cortical serotonergic and catecholaminergic innervation of the frontal cortex has been reported at early stages of Parkinson's disease (PD). However, the limited availability of animal models that exhibit these pathological features has hampered our understanding of the functional significance of these changes during the course of the disease. In the present study, we assessed longitudinal changes in cortical serotonin and catecholamine innervation in motor-symptomatic and asymptomatic monkeys chronically treated with low doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Densitometry and unbiased stereological techniques were used to quantify changes in serotonin and tyrosine hydroxylase (TH) immunoreactivity in frontal cortices of 3 control monkeys and 3 groups of MPTP-treated monkeys (motor-asymptomatic [N = 2], mild parkinsonian [N = 3], and moderate parkinsonian [N = 3]). Our findings revealed a significant decrease (P < 0.001) in serotonin innervation of motor (Areas 4 and 6), dorsolateral prefrontal (Areas 9 and 46), and limbic (Areas 24 and 25) cortical areas in motor-asymptomatic MPTP-treated monkeys. Both groups of symptomatic MPTP-treated animals displayed further serotonin denervation in these cortical regions (P < 0.0001). A significant loss of serotonin-positive dorsal raphe neurons was found in the moderate parkinsonian group. On the other hand, the intensity of cortical TH immunostaining was not significantly affected in motor asymptomatic MPTP-treated monkeys, but underwent a significant reduction in the moderate symptomatic group (P < 0.05). Our results indicate that chronic intoxication with MPTP induces early pathology in the corticopetal serotonergic system, which may contribute to early non-motor symptoms in PD.

Study on the Regulation Effect of Optogenetic Technology on LFP of the Basal Ganglia Nucleus in Rotenone-Treated Rats

Background

Parkinson's disease (PD) is a common neurological degenerative disease that cannot be completely cured, although drugs can improve or alleviate its symptoms. Optogenetic technology, which stimulates or inhibits neurons with excellent spatial and temporal resolution, provides a new idea and approach for the precise treatment of Parkinson's disease. However, the neural mechanism of photogenetic regulation remains unclear.

Objective

In this paper, we want to study the nonlinear features of EEG signals in the striatum and globus pallidus through optogenetic stimulation of the substantia nigra compact part.

Methods

Rotenone was injected stereotactically into the substantia nigra compact area and ventral tegmental area of SD rats to construct rotenone-treated rats. Then, for the optogenetic manipulation, we injected adeno-associated virus expressing channelrhodopsin to stimulate the globus pallidus and the striatum with a 1 mW blue light and collected LFP signals before, during, and after light stimulation. Finally, the collected LFP signals were analyzed by using nonlinear dynamic algorithms.

Results

After observing the behavior and brain morphology, 16 models were finally determined to be successful. LFP results showed that approximate entropy and fractal dimension of rats in the control group were significantly greater than those in the experimental group after light treatment (p < 0.05). The LFP nonlinear features in the globus pallidus and striatum of rotenone-treated rats showed significant statistical differences before and after light stimulation (p < 0.05).

Conclusion

Optogenetic technology can regulate the characteristic value of LFP signals in rotenone-treated rats to a certain extent. Approximate entropy and fractal dimension algorithm can be used as an effective index to study LFP changes in rotenone-treated rats.

Blockade of pre-synaptic and post-synaptic GABAB receptors in the lateral habenula produces different effects on anxiety-like behaviors in 6-hydroxydopamine hemiparkinsonian rats

Although the output of the lateral habenula (LHb) controls the activity of midbrain dopaminergic and serotonergic systems, which are implicated in the pathophysiology of anxiety, it is not known how blockade of GABA_B receptors in the region affects anxiety-like behaviors, particularly in Parkinson's disease-related anxiety. In this study, unilateral 6-hydroxydopamine lesions of the substantia nigra pars compacta in rats induced anxiety-like behaviors, led to hyperactivity of LHb neurons and decreased the level of extracellular dopamine (DA) in the basolateral amygdala (BLA) compared to sham-lesioned rats. Intra-LHb injection of pre-synaptic GABA_B receptor antagonist CGP36216 produced anxiolytic-like effects, while the injection of post-synaptic GABA_B receptor antagonist CGP35348 induced anxiety-like responses in both groups. Further, intra-LHb injection of CGP36216 decreased the firing rate of the neurons, and increased the GABA/glutamate ratio in the LHb and release of DA and serotonin (5-HT) in the BLA; conversely, CGP35348 increased the firing rate of the neurons and decreased the GABA/glutamate ratio and release of DA and 5-HT in sham-lesioned and the lesioned rats. However, the doses of the antagonists producing these behavioral effects in the lesioned rats were lower than those in sham-lesioned rats, and the duration of action of the antagonists on the firing rate of the neurons and release of the neurotransmitters was prolonged in the lesioned rats. Collectively, these findings suggest that pre-synaptic and post-synaptic GABA_B receptors in the LHb are involved in the regulation of anxiety-like behaviors, and degeneration of the nigrostriatal pathway up-regulates function and/or expression of these receptors.

What is the lived experience of anxiety for people with Parkinson's? A phenomenological study

PURPOSE

Anxiety is a common non-motor symptom of Parkinson's and there is no specific pharmacological intervention for people with Parkinson's who experience anxiety. Yet there is little specific research documenting how individuals with this condition experience anxiety. It is important to explore the experiences of people with Parkinson's to identify potential issues in developing future non-pharmacological interventions. This study explored the lived experience of anxiety for people with Parkinson's.

MATERIALS AND METHODS

Six participants were recruited into a descriptive phenomenological study, through the charity Parkinson's UK, using a maximum variation sampling strategy. Face to face interviews were conducted. Data analysis employed thematic analysis.

RESULTS

Three key themes encapsulated the data: Finding ways to cope to "Try not to let it rule your life", Amplifies symptoms "It's emotionally draining it it's also physically draining" and "Anxiety is a funny thing" experienced in myriad ways. A model of the experience of PWP experience of anxiety is proposed.

CONCLUSIONS

Anxiety is a complex experience constructed of interlinked parts affecting people with Parkinson's in myriad ways. Researchers and healthcare professionals should take these findings into account when designing future studies and interventions.

Nociception alterations precede motor symptoms in a progressive model of parkinsonism induced by reserpine in middle-aged rats

Nociception alterations are frequent non-motor symptoms of the prodromal phase of Parkinson's disease (PD). The period for the onset of symptoms and the pathophysiological mechanisms underlying these alterations remain unclear. We investigated the course of nociception alterations in a progressive model of parkinsonism induced by reserpine (RES) in rats. Male Wistar rats (6-7 months) received 5 or 10 subcutaneous injections of RES (0.1 mg/kg) or vehicle daily for 20 days. Motor evaluation and nociceptive assessment were performed throughout the treatment. At the end of the treatment rats were euthanized, the brains removed and processed for immunohistochemical analysis (TH and c-Fos). The RES-treated rats exhibited an increased nociceptive response to mechanical and chemical stimulation in the electronic von Frey and formalin tests, respectively. Moreover, these alterations preceded the motor impairment observed in the catalepsy test. In addition, the RES treatment reduced the TH-immunoreactivity in the ventral tegmental area (VTA) and increased the c-Fos expression in the ventral-lateral periaqueductal gray (vlPAG), rostral ventral medulla (RVM) and dorsal raphe nucleus (DRN) after noxious stimuli induced by formalin. Taken together, our results reinforce that nociceptive changes are one of the early signs of PD and monoamine depletion in basal ganglia can be involved in the abnormal processing of nociceptive information in PD.

Therapeutic effects of Wharton's jelly-derived Mesenchymal Stromal Cells on behaviors, EEG changes and NGF-1 in rat model of the Parkinson's disease

Human Wharton's jelly-derived Mesenchymal Stromal Cells (hWJ-MSCs) have shown beneficial effects in improving the dopaminergic cells in the Parkinson's disease (PD). In the present study, the effects of hWJ-MSCs on hyperalgesia, anxiety deficiency and Pallidal local electroencephalogram (EEG) impairment, alone and combined with L-dopa, were examined in a rat model of PD. Adult male Wistar rats were divided into five groups: 1) sham, 2) PD, 3) PD + C (Cell therapy), 4) PD + C+D (Drug), and 5) PD + D. PD was induced by injection of 6-OHDA (16 μg/2 μl into medial forebrain bundle (MFB)). PD + C group received hWJ-MSCs (1 × 10⁶ cells, intravenous (i.v.)) twice post PD induction. PD + C+D groups received hWJ-MSCs combined with L-Dopa/Carbidopa, (10/30 mg/kg, intraperitoneally (i.p.)). PD + D group received L-Dopa/Carbidopa alone. Four months later, analgesia, anxiety-like behaviors, were evaluated and Pallidal local EEG was recorded. Level of insulin-like growth factor 1 (IGF-1) was measured in the striatum and dopaminergic neurons were counted in substantia nigra (SNc). According to data, MFB-lesioned rats showed hyperalgesia in tail flick, anxiety-like symptoms in cognitive tests, impairment of electrical power of pallidal local EEG as field potential, count of dopaminergic neurons in SNc and level of IGF-1 in striatum. These complications restored significantly by MSCs treatment (p < 0.001). Our findings confirm that chronic treatment with hWJ-MSC, alone and in combination with L-Dopa, improved nociception and cognitive deficit in PD rats which may be the result of increasing IGF-1 and protect the viability of dopaminergic neurons.

Anxiety in Parkinson's disease: Abnormal resting activity and connectivity

Anxiety is a very common yet poorly understood symptom of Parkinson's disease. We investigated whether Parkinson's disease patients experiencing anxiety share neural mechanisms described in the general population with involvement of critical regions for the control of behaviour and movement. Thirty-nine patients with PD were recruited for this study, 20 with higher anxiety scores and 19 with lower anxiety scores. They all underwent a resting-state fMRI scan, while they were on medication. The amplitude of low-frequency fluctuation (ALFF) and seed-based connectivity were investigated to reveal the changes of the spontaneous activity and the interaction among different related regions. The results provided evidence that anxiety in Parkinson's disease is associated with the over-activation of the amygdala and impaired inter-relationship of regions involved in behavior (i.e. medial prefrontal cortex, insula) and motor control (i.e. basal ganglia).

Impaired D2 receptor-dependent dopaminergic transmission in prefrontal cortex of awake mouse model of Parkinson's disease

The loss-of-function mutation in PARK7/DJ-1 is one of the most common causes of autosomal recessive Parkinson's disease, and patients carrying PARK7 mutations often exhibit both a progressive movement disorder and emotional impairment, such as anxiety. However, the causes of the emotional symptom accompanying PARK7-associated and other forms of Parkinson's disease remain largely unexplored. Using two-photon microscopic Ca2+ imaging in awake PARK7-/- and PARK7+/+ mice, we found that (i) PARK7-/- neurons in the frontal association cortex showed substantially higher circuit activity recorded as spontaneous somatic Ca2+ signals; (ii) both basal and evoked dopamine release remained intact, as determined by both electrochemical dopamine recordings and high performance liquid chromatography in vivo; (iii) D2 receptor expression was significantly decreased in postsynaptic frontal association cortical neurons, and the hyper-neuronal activity were rescued by D2 receptor intervention using either local pharmacology or viral D2 receptor over-expression; and (iv) PARK7-/- mice showed anxiety-like behaviours that were rescued by either local D2 receptor pharmacology or overexpression. Thus, for first time, we demonstrated a robust D2 receptor-dependent phenotype of individual neurons within the prefrontal cortex circuit in awake parkinsonian mice that linked with anxiety. Our work sheds light on early-onset phenotypes and the mechanisms underlying Parkinson's disease by imaging brain circuits in an awake mouse model.

Neuropsychiatric aspects of Parkinson disease psychopharmacology: Insights from circuit dynamics

Parkinson disease (PD) is a neurodegenerative disorder with a complex pathophysiology characterized by the progressive loss of dopaminergic neurons within the substantia nigra. Persons with PD experience several motoric and neuropsychiatric symptoms. Neuropsychiatric features of PD include depression, anxiety, psychosis, impulse control disorders, and apathy. In this chapter, we will utilize the National Institutes of Mental Health Research Domain Criteria (RDoC) to frame and integrate observations from two prevailing disease constructions: neurotransmitter anomalies and circuit physiology. When there is available evidence, we posit how unified translational observations may have clinical relevance and postulate importance outside of PD. Finally, we review the limited evidence available for pharmacologic management of these symptoms.

Sensory focused exercise improves anxiety in Parkinson's disease: A randomized controlled trial

Anxiety has been implicated as one of the greatest influences on quality of life in Parkinson’s disease (PD). The etiology of anxiety is unclear, although previous work suggests that anxiety may be linked to sensory deficits that cause uncertainty in movement. Thus, the current study examined whether focusing attention on sensory feedback during goal-based exercise has the potential to provide benefits to anxiety in PD. Thirty-five participants with PD were randomized to either a Sensory Attention Focused Exercise (SAFEx) (i.e. internal focus of attention, n = 18) or Sham Exercise control (i.e. external focus of attention, n = 17) and completed 33 one-hour attention-based exercise sessions over 11-weeks. Before and after the program (pre and post), participants completed the Parkinson Anxiety Scale (PAS) questionnaire. The PAS includes three anxiety sections: persistent, episodic, and avoidance. Changes in the total PAS score and within each section of the PAS were subjected to two-factor mixed repeated measures ANCOVA. Significant group by time interactions demonstrated that from pre to post, total PAS scores (p = 0.007) and episodic anxiety scores (p = 0.010) significantly decreased in the SAFEx group only (ΔTotal PAS = -5.2, F_(1,27) = 5.41, p = 0.028, η_p² = 0.17; ΔEpisodic Score = -1.8, F_(1,27) = 6.89, p = 0.014, η_p² = 0.20). In conclusion, focusing attention on sensory feedback while completing goal-based exercises may provide significant benefits to improving anxiety in PD. As such, sensory attention focused exercise may be a critical adjunct therapy for improving anxiety, and ultimately quality of life in people with PD.

The Aqueous Extract from Ceratonia siliqua Leaves Protects Against 6-hydroxydopamine in Zebrafish: Understanding the Underlying Mechanism

Ceratonia siliqua L. is a Mediterranean medicinal plant traditionally cultivated for its ethnopharmacological benefits, such as antidiarrheal, antidiabetic, enhance acetylcholine, antioxidant, antiatherosclerotic, and for its possible anti-neurodegenerative potential. The aim of the present study was to evaluate the chemical composition, as well as the cognitive-enhancing, anxiolytic, and antioxidant activities of the aqueous extract from C. siliqua (CsAE) leaves against 6-hydroxydopamine (6-OHDA) zebrafish Parkinson’s disease (PD) model. CsAE (0.1, 0.3, and 1 mg/L) was administered by immersion to zebrafish (Danio rerio) for eight consecutive days and one hour before each behavioral test of each day, while 6-OHDA (250 µM) treatment was supplied one day before the novel tank diving test (NTT). Qualitative and quantitative analyses were performed by the ultra-high-performance liquid chromatography (UHPLC) analysis. The memory performance was evaluated through the NTT and Y-maze tests. Additionally, the in vitro and in vivo antioxidant status and acetylcholinesterase (AChE) activity was also assessed. Our finds demonstrated that CsAE presented positive antioxidant and anti-AChE activities, which contributed to the improvement of cognitive function in the 6-OHDA zebrafish PD model.

Biological links between traumatic brain injury and Parkinson's disease

Parkinson's Disease (PD) is a progressive neurodegenerative disorder with no cure. Clinical presentation is characterized by postural instability, resting tremors, and gait problems that result from progressive loss of A9 dopaminergic neurons in the substantia nigra pars compacta. Traumatic brain injury (TBI) has been implicated as a risk factor for several neurodegenerative diseases, but the strongest evidence is linked to development of PD. Mild TBI (mTBI), is the most common and is defined by minimal, if any, loss of consciousness and the absence of significant observable damage to the brain tissue. mTBI is responsible for a 56% higher risk of developing PD in U.S. Veterans and the risk increases with severity of injury. While the mounting evidence from human studies suggests a link between TBI and PD, fundamental questions as to whether TBI nucleates PD pathology or accelerates PD pathology in vulnerable populations remains unanswered. Several promising lines of research point to inflammation, metabolic dysregulation, and protein accumulation as potential mechanisms through which TBI can initiate or accelerate PD. Amyloid precursor protein (APP), alpha synuclein (α-syn), hyper-phosphorylated Tau, and TAR DNA-binding protein 43 (TDP-43), are some of the most frequently reported proteins upregulated following a TBI and are also closely linked to PD. Recently, upregulation of Leucine Rich Repeat Kinase 2 (LRRK2), has been found in the brain of mice following a TBI. Subset of Rab proteins were identified as biological substrates of LRRK2, a protein also extensively linked to late onset PD. Inhibition of LRRK2 was found to be neuroprotective in PD and TBI models. The goal of this review is to survey current literature concerning the mechanistic overlap between TBI and PD with a particular focus on inflammation, metabolic dysregulation, and aforementioned proteins. This review will also cover the application of rodent TBI models to further our understanding of the relationship between TBI and PD.

Long-Term Treatment with Fluvoxamine Decreases Nonmotor Symptoms and Dopamine Depletion in a Postnatal Stress Rat Model of Parkinson's Disease

Nonmotor symptoms (NMS) such as anxiety, depression, and cognitive deficits are frequently observed in Parkinson's disease (PD) and precede the onset of motor symptoms by years. We have recently explored the short-term effects of Fluvoxamine, a selective serotonin reuptake inhibitor (SSRI) on dopaminergic neurons in a parkinsonian rat model. Here, we report the long-term effects of Fluvoxamine, on early-life stress-induced changes in the brain and behavior. We specifically evaluated the effects of Fluvoxamine on brain mechanisms that contribute to NMS associated with PD in a unilateral 6-hydroxydopamine-lesioned rat model. A 14-day early postnatal maternal separation protocol was applied to model early-life stress followed by unilateral intracerebral infusion of 6-hydroxydopamine (6-OHDA) to model aspects of parkinsonism in rats. The anxiolytic, antidepressant, and cognitive effects of Fluvoxamine were confirmed using the elevated plus-maze (EPM) test, sucrose preference test (SPT), and Morris water maze (MWM) test. Further to that, our results showed that animals exposed to early-life stress displayed increased plasma corticosterone and malondialdehyde (MDA) levels which were attenuated by Fluvoxamine treatment. A 6-OHDA lesion effect was evidenced by impairment in the limb-use asymmetry test as well as decreased dopamine (DA) and serotonin levels in the striatum, prefrontal cortex, and hippocampus. These effects were surprisingly attenuated by Fluvoxamine treatment in all treated rats. This study is the first to suggest that early and long-term treatment of neuropsychological diseases with Fluvoxamine may decrease the vulnerability of dopaminergic neurons that degenerate in the course of PD.

Reduction of dopaminergic transmission in the globus pallidus increases anxiety-like behavior without altering motor activity

The globus pallidus (GP) plays an important role in the flow of information between input and output structures of the basal ganglia (BG) circuit. In addition to participating in motor control, the GP may also be involved in cognitive and emotional functions related to the symptoms of patients with Parkinson's disease (PD). Since the GP receives dopaminergic innervation from the substantia nigra pars compacta (SNc), it is important to determine whether a local dopamine (DA) deficit in the GP is related not only to motor but also to the cognitive and emotional alterations of PD. The aim of this study was to examine the effects of lesions in the GP (induced by 6-OHDA) on anxiety, depression and ambulation in rats. Such lesions are known to reduce dopaminergic innervation in this brain structure. Additionally, the effect on DA receptors in the GP was tested by local administration of the dopamine agonist PD168,077, antagonist haloperidol and psychostimulant amphetamine. Experimental anxiety was evaluated with the elevated plus maze (EPM), burying behavior test (BBT) and social interaction test, while depressive-like behavior was assessed with the sucrose preference test. Rats with unilateral and bilateral lesions showed a higher level of anxiety than intact animals in both the EPM and BBT, an effect also obtained after intrapallidal injection of haloperidol. The administration of methamphetamine or PD-168.077 caused the opposite effect. The dopaminergic lesions in the GP did not affect sucrose preference, social interaction or ambulation. These results show that dopamine in the GP, acting through D2 or D4 receptors, may be involved in the manifestation of anxiety, a non-motor symptom of PD that often appears before motor symptoms.

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.

Activation and blockade of α2-adrenoceptors in the prelimbic cortex regulate anxiety-like behaviors in hemiparkinsonian rats

At present, whether α₂-adrenoceptors in the prelimbic cortex (PrL) are involved in Parkinson's disease-related anxiety is unclear. We examined the effects of PrL α₂-adrenoceptors on anxiety-like behaviors in rats with unilateral 6-hydroxydopamine lesions of the medial forebrain bundle. Compared to the sham operation, the lesion induced anxiety-like responses as measured by the open field test and elevated plus-maze test. Intra-PrL injection of the α₂-adrenoceptor agonist clonidine (1.25, 2.5 or 5 μg/rat) produced anxiolytic effects in sham-operated and lesioned rats. Furthermore, intra-PrL injection of the α₂-adrenoceptor antagonist idazoxan (1, 2 or 4 μg/rat) induced anxiogenic effects in two groups of rats. The effective doses produced by clonidine and idazoxan in lesioned rats were higher than those in sham-operated rats. Neurochemical results showed that intra-PrL injection of clonidine (5 μg/rat) or idazoxan (4 μg/rat) decreased or increased dopamine (DA) and noradrenaline (NA) and serotonin (5-HT) levels in the medial prefrontal cortex (mPFC) and amygdala in sham-operated and lesioned rats, respectively. These results suggest that α₂-adrenoceptors in the PrL are involved in the regulation of anxiety-like behaviors, which is attributable to changes in DA, NA and 5-HT levels in the mPFC and amygdala after activation and blockade of α₂-adrenoceptors.

Prophylactic neuroprotective propensity of Crocin, a carotenoid against rotenone induced neurotoxicity in mice: behavioural and biochemical evidence

Previously we have demonstrated the potential neuroprotective propensity of saffron and Crocin (CR) employing a Drosophila model of Parkinsonism. Rotenone (ROT) has been extensively used as a model neurotoxin to induce Parkinson's disease (PD) like symptoms in mice. In the present study, as a proof of concept we evaluated the efficacy of CR prophylaxis (25 mg/ kg bw/d, 7d) to attenuate ROT(0.5 mg/Kg bw/d,7d) -induced neurotoxic effects in male mice focussing on neurobehavioural assessments and biochemical determinants in the striatum. CR prophylaxis significantly alleviated ROT-induced behavioural alterations such as increased anxiety, diminished exploratory behaviour, decreased motor co-ordination, and grip strength. Concomitantly, we evidenced diminution of oxidative stress markers, enhanced levels of antioxidant enzyme and mitochondrial enzyme function in the striatal region. Further, varying degree of restoration of cholinergic function, dopamine and α-synuclein levels were discernible suggesting the possible mechanism/s of action of CR in this model. Based on our earlier data in flies and in worm model, we propose its use as an adjuvant therapeutic agent in oxidative stress-mediated neurodegenerative conditions such as PD.

Usual walking and obstacle avoidance are influenced by depressive and anxiety symptoms in patients with Parkinson's disease

AIM

The aim of the present study was to analyze the association of depressive and anxiety symptoms with usual walking and obstacle avoidance in patients with Parkinson's disease.

METHODS

Patients were divided into three groups: without depressive and anxiety symptoms (n = 28); depressive symptoms only (n = 15); and depressive and anxiety symptoms (n = 19). Symptoms of depression and anxiety were evaluated by the Hospital Anxiety and Depression scale. Participants walked across a pathway in two experimental conditions: usual walking and obstacle avoidance. Kinematic data were recorded using an optoelectronic three-dimensional system.

RESULTS

During usual walking, the depressive and anxiety symptoms group presented shorter stride length and longer double support phase compared with the without depressive and anxiety symptoms group, and lower velocity than the without depressive and anxiety symptoms and depressive symptoms groups. During the approach phase of obstacle avoidance, the depressive and anxiety symptoms group decreased the stride length and velocity, whereas the without depressive and anxiety symptoms and depressive symptoms groups did not modulate these parameters. The depressive and anxiety symptoms group also showed shorter step length and velocity, longer step duration, and wider step width during obstacle crossing. Additionally, the depressive and anxiety symptoms group presented shorter foot-to-obstacle horizontal distances, and lower horizontal mean velocities during obstacle crossing. Partial correlation analyses showed that both depressive and anxiety symptoms were associated with spatiotemporal gait parameters.

CONCLUSION

Combined symptoms of depression and anxiety are associated with walking impairments in patients with Parkinson's disease in both usual walking and obstacle avoidance. Geriatr Gerontol Int 2019; 19: 868-873.

Nonpharmacologic Interventions for the Self-Management of Anxiety in Parkinson's Disease: A Comprehensive Review

Anxiety in Parkinson's disease (aPD) is underdiagnosed, undertreated, and understudied. As many as 50% of persons diagnosed with Parkinson's disease (PD) are reported to suffer from anxiety. Current treatment is largely pharmacologic, which can result in a myriad of undesirable and unsafe side effects. The aim of this paper is to examine intervention studies of self-managed nonpharmacological strategies for the treatment of anxiety. A comprehensive review was conducted on experimental or quasi-experimental trials that included self-management approaches for the nonpharmacologic treatment of anxiety as a primary or secondary aim or outcome measure. Thirteen studies were identified from four databases. Study quality demonstrated variability in design and delivery of self-managed interventions; sample sizes were small; anxiety was most commonly a secondary aim; and the use of anxiety measures varied widely. Statistical significance was evident in slightly more than 50% of the anxiety intervention studies. A common element in the interventions in all studies was the focused use of breath. Further research is needed to determine the feasibility of using focused breathing, alone, as an intervention for the self-management of anxiety in Parkinson's disease.

Multimodal MRI evaluation of parkinsonian limbic pathologies

Previous multimodal magnetic resonance imaging (MRI) studies of parkinsonian syndromes have focused primarily on motor-related basal ganglia structures. The present study investigated MRI changes in nonmotor-related limbic structures in 35 Parkinson's disease, 16 multiple system atrophy parkinsonian subtype, 17 progressive supranuclear palsy, and 37 control subjects. Mean diffusivity (MD), fractional anisotropy, transverse relaxation rate (R2*), quantitative susceptibility mapping, and volume measurements were obtained from the amygdala, hippocampus, and nucleus accumbens (NAc) to examine differences between groups and to test for associations with clinical scores. Compared with controls, Parkinson's disease subjects had lower NAc volume; multiple system atrophy parkinsonian subtype subjects had higher NAc transverse relaxation rate; and progressive supranuclear palsy subjects had higher amygdala and hippocampus MD and lower hippocampus fractional anisotropy (p's ≤ 0.008). Among parkinsonian subjects, amygdala and hippocampus MD associated positively with Unified Parkinson's Disease Rating Scale nonmotor and activities of daily living scores (p's ≤ 0.005). Together, these findings support the inclusion of limbic structures in future MRI studies of parkinsonian syndromes.