Parkinson's disease in women: a call for improved clinical studies and for comparative effectiveness research

Gender gap in deep brain stimulation for Parkinson's disease: preliminary results of a retrospective study

Subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment of PD for both women and men. However, discussions have been reported about the impact of STN-DBS surgery in PD. The aim of our study is to identify differences between men and women in terms of pre- and post-DBS symptoms and try to explain the possible causes. In the current study, we evaluated the gender impact on STN-DBS in PD at the Department of Neurosurgery of University of Naples "Federico II" from 2013 to 2021. Motor and non-motor symptoms were evaluated. To compare the data before and after surgery and between the genders, Wilcoxon-Mann-Whitney tests were performed. A total of 43 patients with PD were included; of them, 17 (39%) were female. Baseline evaluation revealed no gender differences in the age of onset (p = 0.87). Not significant differences were noted in the Unified Parkinson's Disease Rating Scale (UPDRS) pre-surgery score, but if we consider UPDRS subscores of motor examination, significant clinical improvement was reported in both male and female in terms of UPDRS pre- and post-surgery (p < 0.001). STN-DBS is a highly effective treatment for motor and non-motor symptoms of PD for both women and men but our study hints towards gender-specific outcomes in motor domains. Improving our knowledge in this field can allow us to implement strategies to identify new directions in the development of an adequate treatment of PD in terms of surgical intervention and in consideration of the gender.

Sex steroid hormones, the estrous cycle, and rapid modulation of glutamatergic synapse properties in the striatal brain regions with a focus on 17β-estradiol and the nucleus accumbens

The striatal brain regions encompassing the nucleus accumbens core (NAcc), shell (NAcs) and caudate-putamen (CPu) regulate cognitive functions including motivated behaviors, habit, learning, and sensorimotor action, among others. Sex steroid hormone sensitivity and sex differences have been documented in all of these functions in both normative and pathological contexts, including anxiety, depression and addiction. The neurotransmitter glutamate has been implicated in regulating these behaviors as well as striatal physiology, and there are likewise documented sex differences in glutamate action upon the striatal output neurons, the medium spiny neurons (MSNs). Here we review the available data regarding the role of steroid sex hormones such as 17β-estradiol (estradiol), progesterone, and testosterone in rapidly modulating MSN glutamatergic synapse properties, presented in the context of the estrous cycle as appropriate. Estradiol action upon glutamatergic synapse properties in female NAcc MSNs is most comprehensively discussed. In the female NAcc, MSNs exhibit development period-specific sex differences and estrous cycle variations in glutamatergic synapse properties as shown by multiple analyses, including that of miniature excitatory postsynaptic currents (mEPSCs). Estrous cycle-differences in NAcc MSN mEPSCs can be mimicked by acute exposure to estradiol or an ERα agonist. The available evidence, or lack thereof, is also discussed concerning estrogen action upon MSN glutamatergic synapse in the other striatal regions as well as the underexplored roles of progesterone and testosterone. We conclude that there is strong evidence regarding estradiol action upon glutamatergic synapse function in female NAcs MSNs and call for more research regarding other hormones and striatal regions.

Association of Parkinson's disease status with accelerometer-derived physical activity and sedentary behavior in older women: The Women's Health Study (WHS)

Evidence suggests that individuals diagnosed with Parkinson's Disease (PD) spend less time in moderate-to-vigorous intensity physical activity (MVPA) compared to those without PD. However, prior studies primarily included men and did not consider movement across the entire intensity spectrum. To address these gaps, the association of PD status with total volume physical activity and time spent in sedentary, low light-intensity physical activity (LLPA), high light-intensity physical activity (HLPA), and MVPA among older women was examined. This is a cross-sectional analysis of 17,466 ambulatory women enrolled in the Women's Health Study (WHS) with a median (IQR) age of 70 (67-75) years who were asked to wear an accelerometer for 7 days from 2011 to 2015 for the ancillary study. Reported PD status was assessed via annual mail-in questionnaires prior to device wear. Compared to those without PD (n = 16,661), PD (n = 80) was associated with 98,400 fewer vector magnitude (VM) counts per day and with spending an average of 23.2 more minutes per day sedentary and 10.5 more minutes per day in LLPA. Further, PD was associated with spending 6.4 and 27.3 fewer minutes per day in HLPA and MVPA, respectively, compared to women without PD. PD in women is associated with more daily sedentary time and less time spent in health-enhancing physical activity. Prevention strategies to promote physical activity should be emphasized to enhance health and limit progression of disability in women living with PD.

Neuroprotective role for RORA in Parkinson's disease revealed by analysis of post-mortem brain and a dopaminergic cell line

Parkinson's disease (PD) is almost twice as prevalent in men, which has largely been attributed to neuroprotective effect of oestradiol in women. RORA (retinoic acid receptor-related orphan receptor alpha) regulates the transcription of central aromatase, the enzyme responsible for local oestradiol synthesis, simultaneously, RORA expression is regulated by sex hormones. Moreover, RORA protects neurones against oxidative stress, a key mechanism contributing to the loss of dopaminergic neurones in PD. Therefore, we hypothesized that there would be sex differences in RORA expression in the substantia nigra pars compacta (SNpc), which could contribute to sex differences observed in PD prevalence and pathogenesis. In a case control study, qPCR and western blot analyses were used to quantify gene and protein expression in the SNpc of post-mortem brains (n = 14 late-stage PD and 11 age and sex matched controls). The neuroprotective properties of a RORA agonist were then investigated directly using a cell culture toxin-based model of PD coupled with measures of viability, mitochondrial function and apoptosis. RORA was expressed at significantly higher levels in the SNpc from control females' brains compared to males. In PD, we found a significant increase in SNpc RORA expression in male PD compared to female PD. Treatment with a RORA agonist showed a significant neuroprotection in our cell culture model of PD and revealed significant effects on intracellular factors involved in neuronal survival and demise. This study is the first to demonstrate a sex specific pattern of RORA protein and gene expression in the SNpc of controls post-mortem human brains, and to show that this is differentially altered in male and female PD subjects, thus supporting a role for RORA in sex-specific aspects of PD. Furthermore, our in vitro PD model indicates mechanisms whereby a RORA agonist exerts its neuroprotective effect, thereby highlighting the translational potential for RORA ligands in PD.

Care access and utilization among medicare beneficiaries living with Parkinson's disease

An estimated 90% of people living with Parkinson's disease (PD) in the US are covered by Medicare health insurance. How these beneficiaries use and engage the health care system is important to understand in the face of a rapidly growing PD population. Here, we analyzed health care utilization patterns of those with a PD diagnosis enrolled in Medicare in 2019. By our estimates, PD beneficiaries number 685,116 or 1.2% of the total Medicare population. Compared to the overall Medicare population, 56.3% are male (vs 45.6%), 77.9% over age 70 (vs 57.1%), 14.7% people of color (vs 20.7%), and 16.0% are rural residents (vs 17.5%). Our analysis identified significant disparities in care. Surprisingly, 40% of PD beneficiaries (n = 274,046) did not see a neurologist at all during the calendar year and only 9.1% visited a movement disorder specialist (MDS). Few Medicare beneficiaries diagnosed with PD use recommended services such as physical, occupational, or speech therapy. People of color and rural residents were least likely to access a neurologist or therapy services. Despite 52.9% of beneficiaries being diagnosed with depression, only 1.8% had a clinical psychology visit. Our findings emphasize the need for further research on population-specific barriers to accessing PD-related health care.

Association of women-specific health factors in the severity of Parkinson's disease

Parkinson's disease (PD) is an age-related neurological disorder known for the observational differences in its risk, progression, and severity between men and women. While estrogen has been considered to be a protective factor in the development of PD, there is little known about the role that fluctuations in hormones and immune responses from sex-specific health experiences have in the disease's development and severity. We sought to identify women-specific health experiences associated with PD severity, after adjusting for known PD factors, by developing and distributing a women-specific questionnaire across the United States and creating multivariable models for PD severity. We created a questionnaire that addresses women's specific experiences and their PD clinical history and deployed it through The Parkinson's Foundation: PD Generation. To determine the association between women-specific health factors and PD severity, we constructed multivariable logistic regression models based on the MDS-UPDRS scale and the participants' questionnaire responses, genetics, and clinical data. For our initial launch in November 2021, we had 304 complete responses from PD GENEration. Univariate and multivariate logistic modeling found significant associations between major depressive disorder, perinatal depression, natural childbirth, LRRK2 genotype, B12 deficiency, total hysterectomy, and increased PD severity. This study is a nationally available questionnaire for women's health and PD. It shifts the paradigm in understanding PD etiology and acknowledging how sex-specific experiences may contribute to PD severity. In addition, the work in this study sets the foundation for future research to investigate the factors behind sex differences in PD.

ERα Stimulation Rapidly Modulates Excitatory Synapse Properties in Female Rat Nucleus Accumbens Core

INTRODUCTION

The nucleus accumbens core (NAcc) is a sexually differentiated brain region that is modulated by steroid hormones such as 17β-estradiol (estradiol), with consequential impacts on relevant motivated behaviors and disorders such as addiction, anxiety, and depression. NAcc estradiol levels naturally fluctuate, including during the estrous cycle in adult female rats, which is analogous to the menstrual cycle in adult humans. Across the estrous cycle, excitatory synapse properties of medium spiny neurons rapidly change, as indicated by analysis of miniature excitatory postsynaptic currents (mEPSCs). mEPSC frequency decreases during estrous cycle phases associated with high estradiol levels. This decrease in mEPSC frequency is mimicked by acute topical exposure to estradiol. The identity of the estrogen receptor (ER) underlying this estradiol action is unknown. Adult rat NAcc expresses three ERs, all extranuclear: membrane ERα, membrane ERβ, and GPER1.

METHODS

In this brief report, we take a first step toward addressing this challenge by testing whether activation of ERs via acute topical agonist application is sufficient for inducing changes in mEPSC properties recorded via whole-cell patch clamp.

RESULTS

An agonist of ERα induced large decreases in mEPSC frequency, while agonists of ERβ and GPER1 did not robustly modulate mEPSC properties.

CONCLUSIONS

These data provide evidence that activation of ERα is sufficient for inducing changes in mEPSC frequency and is a likely candidate underlying the estradiol-induced changes observed during the estrous cycle. Overall, these findings extend our understanding of the neuroendocrinology of the NAcc and implicate ERα as a primary target for future studies.

The impact of multiple gender dimensions on health-related quality of life in persons with Parkinson's disease: an exploratory study

Background

There is a growing recognition that sex characteristics and gender-related aspects can have a substantial impact on the health-related quality of life (HRQoL) of persons with Parkinson’s disease (PD). Gender is a multidimensional construct, including dynamic social norms and relations that influence health and impact quality of life. Even when gender is investigated in the field of PD, it is frequently conceptualized as gender identity while other dimensions, such as roles or relations, are generally ignored. The aim of this study was to explore the impact of several gender dimensions on HRQoL among people with PD.

Methods

We performed a survey-based, cross-sectional study in the Netherlands to explore the impact of several gender dimensions, namely; gender identity, gender roles and gender relations on HRQoL (PDQ-39) of people with PD.

Results

In our study population (N = 307), including 127 (41%) women, we did not observe an association between gender identity and overall HRQoL. In contrast, an androgynous gender role and higher engagement in household tasks were associated with better overall HRQoL among people with PD.

Conclusions

This study offers the first detailed description of the impact of different gender dimensions on the HRQoL of people with PD and highlights the need for more precise gender-measures to inform actionable gender-sensitive health interventions for people with PD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-022-11228-2.

The estrous cycle and 17β-estradiol modulate the electrophysiological properties of rat nucleus accumbens core medium spiny neurons

The nucleus accumbens core is a key nexus within the mammalian brain for integrating the premotor and limbic systems and regulating important cognitive functions such as motivated behaviors. Nucleus accumbens core functions show sex differences and are sensitive to the presence of hormones such as 17β-estradiol (estradiol) in normal and pathological contexts. The primary neuron type of the nucleus accumbens core, the medium spiny neuron (MSN), exhibits sex differences in both intrinsic excitability and glutamatergic excitatory synapse electrophysiological properties. Here, we provide a review of recent literature showing how estradiol modulates rat nucleus accumbens core MSN electrophysiology within the context of the estrous cycle. We review the changes in MSN electrophysiological properties across the estrous cycle and how these changes can be mimicked in response to exogenous estradiol exposure. We discuss in detail recent findings regarding how acute estradiol exposure rapidly modulates excitatory synapse properties in nucleus accumbens core but not caudate-putamen MSNs, which mirror the natural changes seen across estrous cycle phases. These recent insights demonstrate the strong impact of sex-specific estradiol action upon nucleus accumbens core neuron electrophysiology.

The quality of life in patients with Parkinson's disease: Focus on gender difference

BACKGROUND

To improve understanding of gender differences on quality of life (QoL) in patients with Parkinson's disease (PWP) of a different race, the differences of clinical features and health-related quality of life (HRQoL) between male and female PWP were studied in a small cohort early to middle stage of Chinese PWP.

METHODS

A cross-sectional study was carried out. PWP were consecutively included from April 2020 to July 2021 in Beijing Rehabilitation Hospital. HRQoL, motor symptoms, and nonmotor symptoms in each patient were evaluated. The differences of demographic, motor symptoms assessments, nonmotor symptoms assessments, and QoL between two gender groups were tested using t-test statistics, Mann-Whitney-Wilcoxon test, or χ² depending on the data type. To eliminate the possible factors contributing to the QoL, linear regression models were constructed to sort out the effect of gender.

RESULTS

One hundred and sixty-two Parkinson's disease (PD) patients were included. Demographic, clinical characteristics, and symptom scale assessments had no statistical differences except for levodopa equivalent daily dose, Hamilton Anxiety Rating Score, REM sleep behavior disorder sleep questionnaire, and Hyposmia Rating Scale score. After baseline imbalance corrections, a significantly higher score of PD Questionnaire-39 (PDQ-39) in female than in male patients(p<.05) was found. In the questionnaire, summary Index and bodily discomfort, stigma, and emotional well-being subscores were the main contribution differences.

CONCLUSIONS

Gender differences are associated with the QoL in the early to middle stage PWP in China. Female patients have poorer QoL than male patients, especially bodily discomfort, stigma, and emotional well-being.

Feasibility and effectiveness appraisal of a neurology residency health equities curriculum

BACKGROUND

Despite increasing awareness of inequities in healthcare in neurology, health equity is not a core competency of neurology training. To meet this need, we implemented a health equities curriculum for neurology residents at the Hospital of the University of Pennsylvania.

METHODS

A seven-lecture health equities curriculum was implemented during the 2019-2020 academic year. Surveys were distributed pre-and post-curriculum to assess resident demographics, previous training in health equities, curriculum effectiveness addressing health equities topics, and resident appraisal of the curriculum.

RESULTS

On average, residents attended 2-3 lectures. Most of the residents who participated were White-Non Latinx women. Residents who did not participate in the curriculum listed clinical responsibilities as the main reason for absenteeism. Residents who participated felt the curriculum was at least somewhat effective in addressing health disparities, cultural competency, and implicit bias. 64% of the residents felt the curriculum was effective in improving their preparedness in caring for underserved patients.

CONCLUSION

Implementing a health equities curriculum in neurology residency programs is feasible and well-received by residents. Given inconsistent attendance and a small sample size, we are unable to assess its true effectiveness. Nonetheless, residents felt it prepared them in addressing disparities in neurological care. A longer curriculum will help in assessing the effectiveness of this curriculum intervention. A standard health equities curriculum should be implemented across neurology residency programs, and health equities should be considered a core competency topic for the American Board of Psychiatry and Neurology (ABPN) certification.

Role of toll-like receptor 4 and sex in 6-hydroxydopamine-induced behavioral impairments and neurodegeneration in mice

Parkinson's disease (PD) is a neurodegenerative disease characterized by progressive loss of the nigrostriatal dopaminergic neurons that are associated with motor alterations and non-motor manifestations (such as depression). Neuroinflammation is a process with a critical role in the pathogenesis of PD. In this regard, toll-like receptor 4 (TLR4) is a central mediator of immune response in PD. Moreover, there are gender-related differences in the incidence, prevalence, and clinical features of PD. Therefore, we aimed to elucidate the role of TLR4 in the sex-dependent response to dopaminergic denervation induced by 6-hydroxydopamine (6-OHDA) in mice. Female and male adult wildtype (WT) and TLR4 knockout (TLR4-/-) mice were administered with unilateral injection of 6-OHDA in the dorsal striatum, and non-motor and motor impairments were evaluated for 30 days, followed by biochemistry analysis in the substantia nigra pars compacta (SNc), dorsal striatum, and dorsoventral cortex. Early non-motor impairments (i.e., depressive-like behavior and spatial learning deficits) induced by 6-OHDA were observed in the male WT mice but not in male TLR4-/- or female mice. Motor alterations were observed after administration of 6-OHDA in both strains, and the lack of TLR4 was also related to motor commitment. Moreover, ablation of TLR4 prevented 6-OHDA-induced dopaminergic denervation and microgliosis in the SNc, selectively in female mice. These results reinforced the existence of sex-biased alterations in PD and indicated TLR4 as a promising therapeutic target for the motor and non-motor symptoms of PD, which will help counteract the neuroinflammatory and neurodegenerative processes.

Activities of daily living as a longitudinal moderator of the effect of autonomic dysfunction on anxiety and depression of Parkinson's patients

BACKGROUND

There is no clear time point for the onset of depression and anxiety in Parkinson's disease (PD), and their atypical physical symptoms often overlap with other nonmotor symptoms. Autonomic dysfunction usually appears earlier than motor symptoms, seriously impairing activities of daily living (ADL), even quality of life. Whether autonomic dysfunction can affect depression and anxiety in PD patients through ADL is still unclear.

METHODS

We conducted three progressive autoregressive mediation models to evaluate whether ADL may mediate the association between autonomic symptom burden, where the mediation chain with autonomic function as an independent variable, ADL as a mediating variable, and anxiety and depression as dependent variables. The ADL of PD patients were measured by the Scales for Outcomes in Parkinson's disease-Autonomic (SCOPA-AUT) and Modified Schwab and England ADL scale, respectively, and the status of depression and anxiety were measured by the Geriatric Depression Scale (GDS) and State-Trait Anxiety Inventory (STAI).

RESULTS

There were 338 PD patients, including 220 males and 118 females. Demographic information, including age, gender, and education level, were not correlated with the depression and anxiety. Model III had the smallest AIC (AIC = 12,669.89), and the cross-lagged relations were not statistically significant, so we selected Model II as the optimal model. In Model II, longitudinal autoregressive mediated effect and longitudinal mediated effect of autonomic dysfunction affecting anxiety and depression through ADL were not statistically significant, suggesting longitudinal changes of autonomic dysfunction were independent of anxiety and depression through ADL. Contemporaneous mediated effects of autonomic dysfunction affecting anxiety and depression through ADL were statistically significant, suggesting contemporaneous autonomic dysfunction may contribute to anxiety and depression through ADL.

CONCLUSIONS

Targeted prevention and intervention measures for autonomic dysfunction and ADL should be taken to preserve and improve self-perceived life satisfaction in the clinical practice and preventive health care of PD.

Sex effects on brain structure in de novo Parkinson's disease: a multimodal neuroimaging study

Parkinson's disease varies in severity and age of onset. One source of this variability is sex. Males are twice as likely as females to develop Parkinson's disease, and tend to have more severe symptoms and greater speed of progression. However, to date, there is little information in large cohorts on sex differences in the patterns of neurodegeneration. Here we used MRI and clinical information from the Parkinson Progression Markers Initiative to measure structural brain differences between sexes in Parkinson's disease after regressing out the expected effect of age and sex. We derived atrophy maps from deformation-based morphometry of T1-weighted MRI and connectivity from diffusion-weighted MRI in de novo Parkinson's disease patients (149 males: 83 females) with comparable clinical severity, and healthy control participants (78 males: 39 females). Overall, even though the two patient groups were matched for disease duration and severity, males demonstrated generally greater brain atrophy and disrupted connectivity. Males with Parkinson's disease had significantly greater tissue loss than females in 11 cortical regions including bilateral frontal and left insular lobe, right postcentral gyrus, left inferior temporal and cingulate gyrus and left thalamus, while females had greater atrophy in six cortical regions, including regions in the left frontal lobe, right parietal lobe, left insular gyrus and right occipital cortex. Local efficiency of white matter connectivity showed greater disruption in males in multiple regions such as basal ganglia, hippocampus, amygdala and thalamus. These findings support the idea that development of Parkinson's disease may involve different pathological mechanisms and yield distinct prognosis in males and females, which may have implications for research into neuroprotection, and stratification for clinical trials.

The impact of Lee Silverman Voice Treatment (LSVT LOUD®) on voice, communication, and participation: Findings from a prospective, longitudinal study

BACKGROUND

Lee Silverman Voice Treatment (LSVT LOUD®), an intensive 4-week program of voice therapy, is regarded as the most well-researched, efficacious treatment for hypokinetic dysarthria in individuals with Parkinson's disease (PD). Although numerous studies have published acoustic and perceptual findings, there is comparatively little information about the impact of LSVT LOUD® on functional communication outcomes.

METHODS

This prospective, longitudinal study investigated the impact of treatment on daily communication in 25 individuals with PD. Three validated communication measures (the Voice Handicap Index, the Communicative Effectiveness Scale, and the Communicative Participation Item Bank) were given before and after treatment and again 4-8 weeks and 3-6 months following treatment. Communication partners were also asked to rate communication effectiveness at all four timepoints.

RESULTS

Significant improvements were found for all three self-reported scales which remained above baseline across all post-treatment timepoints. In addition, self-reported communicative effectiveness was significantly correlated with the assessments of communication partners. Particular benefits were reported for more complex communicative activities such as asking questions, giving detailed information, communicating in noisy situations, and speaking in groups.

CONCLUSIONS

Overall, the findings suggested that LSVT LOUD® promotes an increased sense of personal control over the communication difficulties resulting from PD by decreasing voice handicap and improving communication effectiveness and communicative participation. For individuals with PD, LSVT LOUD® may reduce the risk of social isolation by improving communication and facilitating social participation.

LEARNING OUTCOMES

As a result of this activity, the participant will be able to (1) describe the impact of PD on voice and communication, (2) discuss how these characteristics may be associated with more global measures of functional communication and particularly communicative participation, (3) explain which aspects of functional communication were affected by LSVT LOUD® as assessed by study participants and their communication partners.

The Impact of Sex and Gender on the Multidisciplinary Management of Care for Persons With Parkinson's Disease

The impact of sex and gender on disease incidence, progression, and provision of care has gained increasing attention in many areas of medicine. Biological factors–sex–and sociocultural and behavioral factors–gender–greatly impact on health and disease. While sex can modulate disease progression and response to therapy, gender can influence patient-provider communication, non-pharmacological disease management, and need for assistance. Sex and gender issues are especially relevant in chronic progressive diseases, such as Parkinson's disease (PD), because affected patients require multidisciplinary care for prolonged periods of time. In this perspective paper, we draw from evidence in the field of PD and various other areas of medicine to address how sex and gender could impact PD care provision. We highlight examples for which differences have been reported and formulate research topics and considerations on how to optimize the multidisciplinary care of persons with PD.

Evolution of Initial Pharmacologic Treatment of Newly Diagnosed Parkinson's Disease Patients over a Decade in Singapore

Objective

The aim of this study is to compare Parkinson's disease (PD) treatment practices by movement disorder (MD) specialists across a decade, and to determine the factors that influence drug choice for the motor symptoms of PD in newly diagnosed drug-naïve patients.

Methods

This prospective temporal analysis included patients seen at the National Neuroscience Institute in Singapore and diagnosed with PD by MD specialists in the years 2007 and 2017. Primary outcomes were use of specific PD drugs and changes in drug-prescribing patterns. Descriptive analyses and multivariable logistic regression models determined the extent to which patient characteristics were associated with type of PD treatment.

Results

Of 230 patients with PD (mean (SD) age, 66.7 (10.3) years), 131 (57.0%) were male. From 2007 to 2017, the use of ergot dopamine agonists and anticholinergics decreased from 19.3% to 2.0% (P < 0.001) and from 12.0% to 2.7% (P = 0.004), respectively. The use of monoamine oxidase B inhibitors (MAOBI) increased from 13.3% to 25.2% (P = 0.033). The use of levodopa (LD)-sparing strategies decreased nonsignificantly from 33.7% to 24.5% (P = 0.133). Overall, 196 (85.2%) patients were initiated on symptomatic monotherapy, with LD being the most commonly prescribed. MAOBI was the most common drug used in combination therapy. Age ≤70 (adjusted OR, 11.9; 95% CI, 4.5–31.5) and Hoehn and Yahr (HY) stage <2 (adjusted OR, 3.4; 95% CI, 1.5–7.7) were independent factors for LD-sparing strategies. Non-LD prescriptions (13 of 92; 14.1%) were more likely to be discontinued compared to LD ones (6 of 149; 4.0%) (P = 0.005).

Conclusions

Drug-prescribing patterns in PD have changed significantly through the last decade, influenced by emerging evidence and reports of adverse drug effects. Choosing drugs based on the patient's age and disease severity remain sound guiding principles across the years. It is important that international and national guidelines for pharmacotherapy in PD be updated consistently throughout different socioeconomic settings to optimize care.

Sleep in Parkinson's disease: A systematic review and meta-analysis of polysomnographic findings

Polysomnographic studies have been conducted to explore sleep changes in Parkinson's disease (PD), but the relationships between sleep disturbances and PD are imperfectly understood. We conducted a systematic review of the literature exploring polysomnographic differences between PD patients and controls in EMBASE, MEDLINE, All EBM databases, CINAHL, and PsycIFNO. 67 studies were identified for systematic review, 63 of which were used for meta-analysis. Meta-analyses revealed significant reductions in total sleep time, sleep efficiency, N2 percentage, slow wave sleep, rapid eye movement sleep (REM) percentage, and increases in wake time after sleep onset, N1 percentage, REM latency, apnea hypopnea index, and periodic limb movement index in PD patients compared with controls. There were no remarkable differences in sleep continuity or sleep architecture between PD patients with and without REM sleep behavior disorder (RBD). Our study suggests that PD patients have poor sleep quality and quantity. Sex, age, disease duration, presence of RBD, medication status, cognitive impairment, and adaptation night are factors that contributed to heterogeneity between studies.

Activities of daily living in Parkinson's disease: Time/gender perspective

OBJECTIVE

The objectives of this study were to explore the changes in the activities of daily living (ADL) in persons with Parkinson's disease (pwPD) over time and to investigate possible differences in ADL performance between men and women with PD.

MATERIALS & METHODS

One hundred twenty-nine persons (76 men) with a clinically established PD self-assessed their ADL performance from the time of diagnosis up to 8 years follow-up using the ADL taxonomy. Other demographic and clinical data (motor state, cognition, depression) were also collected and subjected to further analysis.

RESULTS

Nine of 12 domains in the ADL taxonomy showed a change over time (Eating and Drinking [P = .009], Mobility [P < .001], Toilet activities [P = .031], Dressing [P < .001], Personal hygiene [P < .001], Communication [P < .001], Cooking [P = .001], Shopping [P < .001] and Cleaning [P < .001]). In addition to time, two domains, (Shopping [P = .007] and Cleaning [P = .027]) also showed an effect of gender with worse scores in women. The nine ADL domains showing effect of time, showed temporary improvement at 12 months follow-up, most probably due to dopaminergic medication. All nine domains deteriorated at later follow-up.

CONCLUSIONS

As expected, there was deterioration in self-assessed performance in the majority od ADL domains over time. Women assessed their ADLs worse in two domains (Shopping and Cleaning) probably reflecting a general gender-related activity pattern rather than being a PD-specific finding.

An overview of the neuroendocrine system in Parkinson's disease: what is the impact on diagnosis and treatment?

Introduction: A growing body of evidence indicates that neuroendocrine interactions may occur at all levels of the brain-gut-microbiota axis, which is directly involved in the pathogenesis of Parkinson's disease (PD).Areas covered: The review presents some current and emerging concepts regarding the organization and functioning of the neuroendocrine system as well as the role of neuroendocrine disturbances in the pathophysiology and symptomatology of PD. The concept of the brain-gut-microbiota triad interactions in the neuroendocrine system and PD is proposed. In PD, dysregulation of the main neuroendocrine axes coordinated by the hypothalamus is accompanied by disruptions at the peripheral level, which involve enteroendocrine cells producing numerous neuropeptides. Moreover, the important role of the gut microbiota as a main coordinator of immune and neuroendocrine interactions is discussed. The potential diagnostic and therapeutic implications in the context of the recent developments in the fields of neuroendocrinology and neurodegeneration are also presented.Expert opinion: Unraveling complex neuroendocrine interactions in the course of PD may provide crucial diagnostic implications and novel therapeutic approaches including the application of gut neuropeptides and gut microbiota modification.

Clinical and dopamine transporter imaging characteristics of non-manifest LRRK2 and GBA mutation carriers in the Parkinson's Progression Markers Initiative (PPMI): a cross-sectional study

BACKGROUND

The Parkinson's Progression Markers Initiative (PPMI) is an ongoing observational, longitudinal cohort study of participants with Parkinson's disease, healthy controls, and carriers of the most common Parkinson's disease-related genetic mutations, which aims to define biomarkers of Parkinson's disease diagnosis and progression. All participants are assessed annually with a battery of motor and non-motor scales, 123-I Ioflupane dopamine transporter (DAT) imaging, and biological variables. We aimed to examine whether non-manifesting carriers of LRRK2 and GBA mutations have prodromal features of Parkinson's disease that correlate with reduced DAT binding.

METHODS

This cross-sectional analysis is based on assessments done at enrolment in the subset of non-manifesting carriers of LRRK2 and GBA mutations enrolled into the PPMI study from 33 participating sites worldwide. The primary objective was to examine baseline clinical and DAT imaging characteristics in non-manifesting carriers with GBA and LRRK2 mutations compared with healthy controls. DAT deficit was defined as less than 65% of putamen striatal binding ratio expected for the individual's age. We used t tests, χ² tests, and Fisher's exact tests to compare baseline demographics across groups. An inverse probability weighting method was applied to control for potential confounders such as age and sex. To account for multiple comparisons, we applied a family-wise error rate to each set of analyses. This study is registered with ClinicalTrials.gov, number NCT01141023.

FINDINGS

Between Jan 1, 2014, and Jan 1, 2019, the study enrolled 208 LRRK2 (93% G2019S) and 184 GBA (96% N370S) non-manifesting carriers. Both groups were similar with respect to mean age, and about 60% were female. Of the 286 (73%) non-manifesting carriers that had DAT imaging results, 18 (11%) LRRK2 and four (3%) GBA non-manifesting carriers had a DAT deficit. Compared with healthy controls, both LRRK2 and GBA non-manifesting carriers had significantly increased mean scores on the Movement Disorders Society Unified Parkinson's Disease Rating Scale (total score 4·6 [SD 4·4] healthy controls vs 8·4 [7·3] LRRK2 vs 9·5 [9·2] GBA, p<0·0001 for both comparisons) and the Scale for Outcomes for PD - autonomic function (5·8 [3·7] vs 8·1 [5·9] and 8·4 [6·0], p<0·0001 for both comparisons). There was no difference in daytime sleepiness, anxiety, depression, impulsive-compulsive disorders, blood pressure, urate, and rapid eye movement (REM) behaviour disorder scores. Hyposmia was significantly more common only in LRRK2 non-manifesting carriers (69 [36%] of 194 healthy controls vs 114 [55%] of 208 LRRK2 non-manifesting carriers; p=0·0003). Finally, GBA but not LRRK2 non-manifesting carriers showed increased DAT striatal binding ratios compared with healthy controls in the caudate (healthy controls 2·98 [SD 0·63] vs GBA 3·26 [0·63]; p<0·0001), putamen (2·15 [0·56] vs 2·48 [0·52]; p<0·0001), and striatum (2·56 [0·57] vs 2·87 [0·55]; p<0·0001).

INTERPRETATION

Our data show evidence of subtle motor and non-motor signs of Parkinson's disease in non-manifesting carriers compared with healthy controls that can precede DAT deficit. Longitudinal data will be essential to confirm these findings and define the trajectory and predictors for development of Parkinson's disease.

FUNDING

Michael J Fox Foundation for Parkinson's Research.

Sex differences in Parkinson's disease presentation and progression

INTRODUCTION

Females have a reduced risk of Parkinson's disease (PD). However, it is unclear if sex is a prognostic factor. We aimed to examine differences in presentation, physician- and patient-reported PD outcomes, and progression by sex in a large clinical cohort.

METHODS

This study was a secondary analysis of a cohort of PD patients seen at a tertiary care center. Sociodemographic and clinical characteristics, treatment, care timing, and outcomes were examined by sex. Sex differences in progression of impairment, disability, and health-related quality of life (HRQoL) were tested with five-year piecewise linear mixed-effects models. A mediation analysis assessed drivers of sex differences.

RESULTS

The study included 914 males and 549 females. Females had significantly less social support, more psychological distress, and worse self-reported (but not physician-reported) disability and HRQoL at initial PD care visits, compared to males. Addressing anxiety symptoms may attenuate this difference. PD progression sex differences were minimal.

CONCLUSION

PD progression does not differ by sex, yet patient-reported measures of disease severity are worse in females than males. To attenuate this sex difference in disease experience, psychological distress screening and management, particularly targeting females, should be implemented as part of PD clinical care.

Sex-related differences in homebound advanced Parkinson's disease patients

Background

Women with Parkinson’s disease (PD) are more likely to be older, have greater disease severity and comorbidities, and yet are less likely to receive care from a neurologist, as compared with men with PD. Within the PD population, homebound individuals are a particularly vulnerable group facing significant barriers to care, yet within this understudied population, sex-related differences have not been reported.

Purpose

To identify and describe differences in homebound men and women with advanced PD and related disorders, participating in an interdisciplinary home visit program.

Patients and methods

This was an exploratory analysis of homebound patients seen between February 2014 and July 2016 using data collected via in-person interviews and chart review.

Results

We enrolled 85 patients, of whom 52% were women. PD was the most common diagnosis (79%), followed by dementia with Lewy bodies (5%), and other atypical parkinsonism (16%). Men were more likely to have a PD dementia diagnosis than women (17.1% vs 2.3%, p=0.03). Women were more likely to live alone (18.1% of women had no caregiver vs 2.4% of men, p=0.05).

Conclusion

The role of the caregiver in facilitating safe aging-in-place is crucial. Among homebound individuals with advanced PD, women were far more likely to live alone. The absence of a spouse or care partner may be due in part to variable sex-based life expectancies. Our findings suggest that homebound women with advanced PD may face greater barriers to accessing support.

Gender Comparisons of Asymmetric Lateralization in Neurodegenerative Disorder Patients via E-Pen Based Cognitive Assessment System

BACKGROUND

The clinical gender-dependent characteristics of visuospatial neglect between men and women have not been elucidated in Korean patients with cognitive impairment. The goal of this study was to observe the asymmetric lateralization in patients using a novel e-pen based cognitive assessment system.

METHODS

A total of 31 patients, 16 men and 15 women, with early stage hemispheric cerebral dysfunction were recruited for the assessment of unilateral neglect suing a novice paper-and-pencil based electronic evaluation system from a rehabilitation center of Inha University hospital in 2016. Results were assessed for degrees of deviations, and numbers of neglected lines. Degree of deviation was assessed using the positions and distances from the horizontal line centers. Effect sizes were calculated to assess proximities between the assessed results.

RESULTS

Comparatively greater left and rightward biasness for the right-sided and left-sided horizontal lines were observed for the male patients, respectively. Moreover, greater degree of left to rightward biasness was observed as the horizontal lines shortened in both groups. However, the magnitude of biasness in female patients showed comparatively less directional bias, indicating greater prevalence for the center of mass effect in male patients.

CONCLUSION

Gender difference in visuospatial neglect seems to exist with less accuracy in recognition for the bisecting center for the female and asymmetrical lateralization and magnitude of deviation for the male patients.

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.

Sex Differences in Medium Spiny Neuron Excitability and Glutamatergic Synaptic Input: Heterogeneity Across Striatal Regions and Evidence for Estradiol-Dependent Sexual Differentiation

Steroid sex hormones and biological sex influence how the brain regulates motivated behavior, reward, and sensorimotor function in both normal and pathological contexts. Investigations into the underlying neural mechanisms have targeted the striatal brain regions, including the caudate-putamen, nucleus accumbens core (AcbC), and shell. These brain regions are of particular interest to neuroendocrinologists given that they express membrane-associated but not nuclear estrogen receptors, and also the well-established role of the sex steroid hormone 17β-estradiol (estradiol) in modulating striatal dopamine systems. Indeed, output neurons of the striatum, the medium spiny neurons (MSNs), exhibit estradiol sensitivity and sex differences in electrophysiological properties. Here, we review sex differences in rat MSN glutamatergic synaptic input and intrinsic excitability across striatal regions, including evidence for estradiol-mediated sexual differentiation in the nucleus AcbC. In prepubertal animals, female MSNs in the caudate-putamen exhibit a greater intrinsic excitability relative to male MSNs, but no sex differences are detected in excitatory synaptic input. Alternatively, female MSNs in the nucleus AcbC exhibit increased excitatory synaptic input relative to male MSNs, but no sex differences in intrinsic excitability were detected. Increased excitatory synaptic input onto female MSNs in the nucleus AcbC is abolished after masculinizing estradiol or testosterone exposure during the neonatal critical period. No sex differences are detected in MSNs in prepubertal nucleus accumbens shell. Thus, despite possessing the same neuron type, striatal regions exhibit heterogeneity in sex differences in MSN electrophysiological properties, which likely contribute to the sex differences observed in striatal function.

Sex disparities in health and health care utilization after Parkinson diagnosis: Rethinking PD associated disability

OBJECTIVE

To examine sex differences and trends in comorbid disease and health care utilization in individuals with newly diagnosed Parkinson disease (PD).

DESIGN

Retrospective cohort study.

PARTICIPANTS

Over 133,000 Medicare beneficiaries with a new PD diagnosis in 2002 followed through 2008.

METHODS

We compared the prevalence and cumulative incidence of common medical conditions, trends in survival and health care utilization between men and women with PD.

RESULTS

Female PD patients had higher adjusted incidence rate ratio (IRR) of depression (IRR: 1.28, 1.25-1.31), hip fracture (IRR: 1.51, 1.45-1.56), osteoporosis (3.01, 2.92-3.1), and rheumatoid/osteoarthritis (IRR: 1.47, 1.43-1.51) than men. In spite of greater survival, women with PD used home health and skilled nursing facility care more often, and had less outpatient physician contact than men throughout the study period.

CONCLUSIONS

Women experience a unique health trajectory after PD diagnosis as suggested by differing comorbid disease burden and health care utilization compared to men. Future studies of sex differences in care needs, care quality, comorbidity related disability, PD progression, and non-clinical factors associated with disability are needed to inform research agendas and clinical guidelines that may improve quality survival for women with PD.

Gender differences in Parkinson's disease: A clinical perspective

Available data indicate that there are gender differences in many features of Parkinson's disease (PD). Precise identification of the gender differences is important to tailor treatment, predict outcomes, and meet other individual and social needs in women and men with PD. The aim of this study was to review the available clinical data on gender differences in PD. Original articles and meta-analyses published between 1990 and 2016 systematically exploring gender differences in PD were reviewed. There is slight male preponderance in incidence and prevalence of PD. PD starts earlier in men. Women tend to be more prone to develop tremor-dominant PD but are less rigid than men. Motor improvement after deep brain stimulation is equal in both sexes, but women tend to show better improvement in activities of daily living. Furthermore, women with PD show better results on tests for general cognitive abilities, outperform men in verbal cognitive tasks, show more pain symptoms, and score higher on depression scales. It seems, however, that the differences in cognition, mood, and pain perception are not disease specific as similar gender differences can be found in healthy subjects and in other neurological conditions. Despite PD being the most frequently studied movement disorder, studies investigating gender differences in PD are still scarce with most of the studies being cross-sectional. Good-quality, prospective, longitudinal studies analyzing gender differences in PD and comparing them to matched healthy controls are needed in order to properly address the issues of gender differences in PD.

Neurochemical and Behavior Deficits in Rats with Iron and Rotenone Co-treatment: Role of Redox Imbalance and Neuroprotection by Biochanin A

Increasing evidences show that the etiology of Parkinson's disease (PD) is multifactorial. Studying the combined effect of several factors is becoming a hot topic in PD research. On one hand, iron is one of the essential trace metals for human body; on the other hand, iron may be involved in the etiopathogenesis of PD. In our present study, the rats with increased neonatal iron (120 μg/g bodyweight) supplementation were treated with rotenone (0.5 mg/kg) when they were aged to 14 weeks. We observed that iron and rotenone co-treatment induced significant behavior deficits (time-dependent) and striatal dopamine depletion in the male and female rats, while they did not do so when they were used alone. No significant change in striatal 5-hydroxytryptamine content was observed in the male and female rats with iron and rotenone co-treatment. Also, iron and rotenone co-treatment significantly decreased substantia nigra TH expression in the male rats. Furthermore, co-treatment with iron and rotenone significantly induced malondialdehyde increase and glutathione decrease in the substantia nigra of male and female rats. There was no significant change in cerebellar malondialdehyde and glutathione content of the rats co-treated with iron and rotenone. Interestingly, biochanin A significantly attenuated striatal dopamine depletion and improved behavior deficits (dose-dependently) in the male and female rats with iron and rotenone co-treatment. Biochanin A treatment also significantly alleviated substantia nigra TH expression reduction in the male rats co-treated with iron and rotenone. Finally, biochanin A significantly decreased malondialdehyde content and increased glutathione content in the substantia nigra of male and female rats with iron and rotenone co-treatment. Our results indicate that iron and rotenone co-treatment may result in aggravated neurochemical and behavior deficits through inducing redox imbalance and increased neonatal iron supplementation may participate in the etiopathogenesis of PD. Moreover, biochanin A may exert dopaminergic neuroprotection by maintaining redox balance.

Gender Differences of Nonmotor Symptoms Affecting Quality of Life in Parkinson Disease

BACKGROUND/AIMS

Gender differences of health-related quality of life (HRQoL) in patients with various disorders have been reported. Various nonmotor symptoms (NMSs) also affect the patients' lives and HRQoL, even in the early stages of Parkinson disease (PD). Our study aimed to identify whether there are gender differences of HRQoL in PD patients in the early stages, and which NMSs are associated with HRQoL depending on gender.

METHOD

Eighty-nine PD patients (47 males, 42 females) and 36 healthy controls were enrolled. We evaluated HRQoL, NMSs, and their associations in each gender.

RESULT

The total Parkinson Disease Quality of Life Questionnaire and Beck Anxiety Inventory scores were higher in female patients than in male patients. The correlation analysis revealed no association between NMSs and HRQoL in male patients. In female patients, HRQoL was highly correlated with depression, and moderately associated with fatigue.

CONCLUSIONS

Gender differences of an association between HRQoL and NMSs exist in PD. We found that fatigue and depression were the main determinants of poor HRQoL in female patients even in the early stages. We suggest that a gender-specific therapeutic approach is important, and it is necessary to pay special attention to the predictors associated with causing poor HRQoL.

Peripheral Lymphocyte Subsets as a Marker of Parkinson's Disease in a Chinese Population

In this study, we conducted a clinical analysis of lymphocyte subtypes in 268 patients with Parkinson's disease (PD) to assess their clinical impact as a potential marker of advanced PD in Chinese patients. The participants comprised 268 sporadic PD patients and 268 healthy controls. The numbers of natural killer (NK) cells and CD3+, CD3+CD4+, CD3+CD8+, and CD19+ lymphocytes from peripheral blood were determined by immunostaining and flow cytometric analysis and the percentages of these CD+ T cells were calculated. The ratio of regulatory T (Treg)/helper T 17 (Th17) lymphocytes from 64 PD patients and 46 controls was determined by flow cytometric analysis. The results showed that the percentage of NK cells was higher in advanced PD patients than in controls (22.92% ± 10.08% versus 19.76% ± 10.09%, P = 0.006), while CD3+ T cells are decreased (62.93% ± 9.27% versus 65.75% ± 9.13%, P = 0.005). The percentage of CD19+ B cells in male patients was lower (P = 0.021) than in female patients, whereas NK cells were increased (P < 0.0001). The scores on the Unified Parkinson's Disease Rating Scale (UPDRS) and the Non-Motor Symptoms Scale in late-onset PD patients were significantly higher than those in early-onset patients (P = 0.024 and P = 0.007, respectively). The percentage of CD19+ B cells in patients with UPDRS scores >24 was lower than in those with scores <24 (10.17% ± 4.19% versus 12.22% ± 5.39%, P = 0.009). In addition, the Treg/Th17 ratio in female patients was higher than that in female controls (13.88 ± 6.32 versus 9.94 ± 4.06, P = 0.042). These results suggest that the percentages of NK cells, CD3+ T cells, and CD19+ B cells along with the Treg/Th17 ratio in peripheral blood may be used to predict the risk of PD in Chinese individuals and provide fresh avenues for novel diagnostic biomarkers and therapeutic designs.

Use of Complementary Health Approaches in Individuals With Parkinson's Disease

Parkinson's disease (PD) is neurodegenerative and requires ongoing therapy. The purpose of the current study was two-fold: to (a) describe the prevalence, types, and associated factors of complementary health approaches (CHA) used in individuals with PD; and (b) explore reasons for CHA use. A self-administered, cross-sectional survey was used. The response rate was 61.9% (N = 135), and 74.1% of participants used CHA for either PD or general health. The most widely used CHA included exercise, yoga, massage, vitamins, coenzyme Q10, and coconut oil. Higher levels of education and treatment by a movement disorder specialist were significantly related to CHA use. Nurses and other health care professionals may have a role in providing safe care for individuals with PD. Further studies on effectiveness and safety of commonly used CHA are warranted. [Journal of Gerontological Nursing, 43(2), 46-54.].

Sexual dimorphism in Parkinson's disease: differences in clinical manifestations, quality of life and psychosocial functioning between males and females

INTRODUCTION

Sex-related differences in clinical manifestations and consequences of Parkinson's disease (PD) have been poorly explored. Better understanding of sexual dimorphism in neurologic diseases such as PD has been announced as a research priority. The aim of our study was to determine independent sex differences in clinical manifestations and subtypes, psychosocial functioning, quality of life (QoL) and its domains between male and female individuals with PD.

PATIENTS AND METHODS

A comprehensive list of demographics, motor symptoms and subtypes, nonmotor features, health-related quality of life (HRQoL), psychosocial functioning and general aspects of daily life was assessed in 157 individuals (108 males and 49 females) with idiopathic PD. In order to control for potential confounding variables, we applied Orthogonal Partial Least Squares - Discriminant Analysis (OPLS-DA) to explore the strength of each feature to discriminate male and female patients with PD.

RESULTS

While no sex difference was found in the total Unified Parkinson's Disease Rating Scale (UPDRS) score and cumulative daily dose of levodopa, females had significantly more severe anxiety (mean difference =2.2 [95% confidence interval, CI: 0.5-4.0], P=0.011), worse nutritional status (23.8 [standard deviation, SD =4.2] vs 25.8 [SD =2.6], P=0.003) and poorer QoL (28.3 [SD =15.7] vs 17.9 [SD =14.2], P<0.001). Based on multivariate discriminant analysis, emotional well-being, bodily discomfort, social support, mobility and communication domains of HRQoL, together with anxiety, depression and psychosocial functioning, were the strongest features with more severe/worse status in females after adjustment for potential statistical confounders.

CONCLUSION

Our study provides a comprehensive understanding of sexual dimorphism in PD. Anxiety, depression, specific domains of HRQoL (mobility, emotional well-being, social support and bodily discomfort) and psychosocial functioning were significantly worse in female individuals with PD. Sexual dimorphism in PD highlights the features that are more likely to be affected in each sex and should be specifically targeted when managing male and female individuals with PD.

Sex differences in acupuncture effectiveness in animal models of Parkinson's disease: a systematic review

Background

Many animal experimental studies have been performed to investigate the efficacy of acupuncture in Parkinson’s disease (PD). Sex differences are a major issue in all diseases including PD. However, to our knowledge, there have been no reviews investigating sex differences on the effectiveness of acupuncture treatment for animal PD models. The current study aimed to summarize and analyze past studies in order to evaluate these possible differences.

Method

Each of 7 databases (MEDLINE, EMBASE, the Cochrane Library, 3 Korean medical databases, and the China National Knowledge Infrastructure) was searched from its inception through March 2015 without language restrictions.

Results

We included studies of the use of acupuncture treatment in animal models of PD. A total of 810 potentially relevant articles were identified, 57 of which met our inclusion criteria. C57/BL6 mice were used most frequently (42 %) in animal PD models. Most of the studies were carried out using only male animals (67 %); only 1 study (2 %) was performed using solely females. The further 31 % of the studies used a male/female mix or did not specify the sex.

Conclusions

The results of our review suggest that acupuncture is an effective treatment for animal PD models, but there is insufficient evidence to determine whether sex differences exist. Future studies of acupuncture treatment for PD should use female animal models because they reflect the physiological characteristics of both males and females to fully evaluate the effect and the safety of the treatment for each sex.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1405-5) contains supplementary material, which is available to authorized users.

Menopause and Parkinson's disease. Interaction between estrogens and brain renin-angiotensin system in dopaminergic degeneration

The neuroprotective effects of menopausal hormonal therapy in Parkinson's disease (PD) have not yet been clarified, and it is controversial whether there is a critical period for neuroprotection. Studies in animal models and clinical and epidemiological studies indicate that estrogens induce dopaminergic neuroprotection. Recent studies suggest that inhibition of the brain renin-angiotensin system (RAS) mediates the effects of estrogens in PD models. In the substantia nigra, ovariectomy induces a decrease in levels of estrogen receptor-α (ER-α) and increases angiotensin activity, NADPH-oxidase activity and expression of neuroinflammatory markers, which are regulated by estrogen replacement therapy. There is a critical period for the neuroprotective effect of estrogen replacement therapy, and local ER-α and RAS play a major role. Astrocytes play a major role in ER-α-induced regulation of local RAS, but neurons and microglia are also involved. Interestingly, treatment with angiotensin receptor antagonists after the critical period induced neuroprotection.

Self-Reported Symptoms of Parkinson's Disease by Sex and Disease Duration

Parkinson's disease (PD) is a neurodegenerative disease with a wide range of symptom presentations. The purpose of this research was to compare self-reported motor and non-motor symptoms of PD by sex and disease duration. This study was a cross-sectional descriptive survey in community-dwelling people with PD. A total of 141 participants (64.6% response rate; 59.6% men; M_age = 69.7 years) were included. Males reported more rigidity, speech problems, sexual dysfunction, memory problems, and socializing problems than females. The number of motor symptoms in three groups divided by increments of 5 years was significantly increased. Postural instability, freezing, off periods, dyskinesia, speech problems, and hallucinations/psychosis were significantly increased as the disease duration increased. Thorough assessment of motor and non-motor symptoms could decrease the risk of inadequate symptom management. Provision of information regarding PD symptoms at each stage may help people with PD and their caregivers in planning their future care and life.

Sex Differences in the Clinical Progression of Parkinson's Disease

OBJECTIVE

To describe characteristics of Parkinson's disease by sex and determine if differences in disease progression exist.

DESIGN

Longitudinal, observational study.

SETTING

Twenty-one National Parkinson Foundation Centers of Excellence.

PARTICIPANTS

People (N = 4,679; 63% men and 37% women) with idiopathic Parkinson's disease.

METHODS

Demographic and clinical data at enrollment and after 1 year were collected. We defined progression as a 1-year change in the following functional health outcome measures: (a) health-related quality of life (Parkinson's Disease Questionnaire-39), (b) Timed Up and Go test, (c) cognitive function, and (d) number of medications. We compared baseline characteristics between men and women. Then, linear regression models were built to assess the independent contribution of sex to progression.

RESULTS

At baseline, women were significantly more likely to be older and have greater disease severity and more comorbidities than men despite similar duration of disease. This finding corresponded to worse function as assessed by the Parkinson's Disease Questionnaire-39 and Timed Up and Go test but not to number of medications and cognitive function. After 1 year, declines across all functional measures except delayed recall occurred. No significant changes in Parkinson's Disease Questionnaire-39, Timed Up and Go, number of medications, or verbal fluency between men and women occurred. Women had a more significant improvement in delayed recall than men.

CONCLUSION

Numerous small baseline differences occurred between men and women with PD, although differences in markers of progression were few. Findings suggest that clinical manifestations and prognosis appear similar by sex under the same treatment conditions.

Sex and Gender Differences in Central Nervous System-Related Disorders

There are important sex differences in the brain that seem to arise from biology as well as psychosocial influences. Sex differences in several aspects of human behavior and cognition have been reported. Gonadal sex steroids or genes found on sex chromosomes influence sex differences in neuroanatomy, neurochemistry and neuronal structure, and connectivity. There has been some resistance to accept that sex differences in the human brain exist and have biological relevance; however, a few years ago, it has been recommended by the USA National Institute of Mental Health to incorporate sex as a variable in experimental and clinical neurological and psychiatric studies. We here review the clinical literature on sex differences in pain and neurological and psychiatric diseases, with the aim to further stimulate interest in sexual dimorphisms in the brain and brain diseases, possibly encouraging more research in the field of the implications of sex differences for treating these conditions.

Aging-related 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurochemial and behavioral deficits and redox dysfunction: improvement by AK-7

Aging is a prominent risk factor for the occurrence and progression of Parkinson disease (PD). Aging animals are more significant for PD research than young ones. It is promising to develop effective treatments for PD through modulation of aging-related molecules. Sirtuin 2 (SIRT2), a strong deacetylase highly expressed in the brain, has been implicated in the aging process. In our present study, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 12mg/kg once daily) was observed to bring about significant behavioral deficits and striatal dopamine depletion in aging male and female mice, while it did not do so in young animals. MPTP did not cause significant reduction in striatal 5-hydroxytryptamine content in aging male and female mice. Furthermore, we observed that MPTP treatment resulted in significant reduction in GSH content and significant increase in MDA content and SIRT2 expression in the substantia nigra (SN) of aging mice, while it did not do so in young animals. Importantly, we observed that AK-7 (a selective SIRT2 inhibitor) significantly improved behavior abnormality and neurochemical deficits in aging male and female mice treated with MPTP. Significant increase in GSH content and significant decrease in MDA content were also observed in the SN of aging male and female mice co-treated with MPTP and AK-7 compared with the MPTP-treated animals. Our results indicated that MPTP induce aging-related neurochemical and behavioural deficits and dysfunction of redox network in male and female mice and AK-7 may be neuroprotective in PD through modulating redox network.

Sex-Related Prognostic Predictors for Parkinson Disease Undergoing Subthalamic Stimulation

BACKGROUND

A few reports have addressed the sex-related efficacy of deep brain stimulation (DBS) in the subthalamic nucleus (STN) to treat advanced Parkinson disease (PD). The present study evaluates the sex-related prognostic factors for STN-DBS outcomes.

METHODS

Seventy-two consecutive patients (48 men and 24 women) were reviewed retrospectively. Changes in the Unified PD Rating Scale scores were compared between men and women in the 6-month drug-off/DBS-on state relative to the preoperative drug-off baseline. A multivariate linear regression model was used to identify the preoperative factors predictive of motor improvements after surgery.

RESULTS

Before surgery, the male and female patient groups were comparable in clinical severity, except the women were associated with slightly inferior cognition (P < 0.05) and a relatively better response to levodopa (LD) (P < 0.05) than the men. Both sexes showed similar clinical improvements after STN-DBS therapy. In men, preoperative lower LD requirement and higher motor dysfunction, particularly tremor (adjusted R(2) = 0.613, P < 0.001), as well as greater improvement in tremor and rigidity after LD therapy (adjusted R(2) = 0.232, P = 0.001) were favorable predictors of surgical outcomes. Women achieved a significant improvement if they performed well in activities of daily living even with higher baseline motor scores (adjusted R(2) = 0.620, P < 0.001), or exhibited improvements in akinesia disability after preoperative LD therapy (adjusted R(2) = 0.305, P = 0.003).

CONCLUSIONS

STN-DBS therapy is equally beneficial for both sexes. Sex-related differences exist with regard to favorable prognostic predictors for early surgical outcomes.

The decision-making process leading to deep brain stimulation in men and women with parkinson's disease - an interview study

Background

Deep brain stimulation (DBS) is an established treatment for patients with advanced parkinson’s disease (PD). Research shows that women are under-represented among patients undergoing DBS surgery. This may be due to gender-biased selection of patients, but patients’ wishes and attitudes may also contribute. This study investigated the decision making process to undergo DBS from the patient’s perspective, and explored any gender patterns in the participants’ decision-making.

Methods

All patients operated on with DBS for PD at the University Hospital of Northern Sweden between January 2002 and April 2010 were invited to an interview study. In this way 39 patients were recruited, 31 men and eight women. Three additional women, operated elsewhere, were recruited to acheive a more gender-balanced sample. In a mixed-method analysis, the interviews were analysed according to the constant comparison technique in grounded theory and descriptive statistics was used to present demographics and compare categories.

Results

Three different approaches to DBS were identified among the patients. ‘Taking own initiative’, included 48% of the patients and implied that the patients’ own initiatives and arguments had been crucial for having surgery. ‘Agreeing when offered’, and accepting DBS when suggested by doctors embraced 43%. The third approach, ‘Hesitating and waiting’ included < 10% of the patients. Most of the men were either ‘taking own initiative’ or ‘agreeing when offered’. The 11 women were evenly distributed in all three approaches. Among the interviewed, more women than men expressed strong fear of complications and more women consulted friends and relatives prior to deciding about DBS. Half of the patients had held a leadership position at work or in another organisation, and among patients ‘taking own initiative’ the proportion with leadership experiences was 80%. At time for surgery ten men but no woman were professionally active.

Conclusion

This study suggests that many patients with advanced PD have to argue and struggle with their clinicians in order to be referred to a DBS-team. The study further suggests that patients’ wishes, behaviour and position in society may all contribute to the skewed gender distribution among patients treated with DBS.

Sex differences in Parkinson's disease

Sex-related differences in Parkinson's disease (PD) have been recognised, but remain poorly understood. We aimed to further clarify real-life differences in disease experience according to sex, by evaluating quality of life (QoL), demographic and clinical characteristics of PD patients. A cross-sectional survey was conducted on 210 PD patients (129 men, 81 women) attending specialist neurological clinics across three centres. Outcome measures included the motor examination of the Unified Parkinson's Disease Rating Scale (UPDRS-III) and QoL as measured by the 39-item Parkinson's Disease Questionnaire (PDQ-39). A male to female ratio of 1.6:1 was observed. Men reported a greater disease burden than women as noted by higher UPDRS-III scores (27 ± 13 versus 23 ± 13, p=0.032), daily levodopa equivalent doses (898.1 ± 481.3mg versus 750.7 ± 427.2mg, p=0.037) and caregiver reliance (44% versus 29.5%, p=0.039). The UPDRS-III score was significantly associated with sex after controlling for age and disease duration, with men more severely affected (β=-0.165, r(2)=0.101, p=0.028). The PDQ-39 showed men reported lower QoL in activities of daily living (ADL), cognition and communication sub-scales (p<0.05). An association was identified in men between PDQ-39 ADL and cognition sub-scales (r=0.660, p<0.001). Men with an appointed caregiver had a higher PDQ-39 Summary Index (t=3.222, degrees of freedom=122, p=0.002). PD was found to have greater overall impact on the health and well-being of male patients in sub-specialty clinical practice. Our study further supports the need for increased sex-delineated clinical assessment and consideration of potential differences required in the management of PD.

Effects of a multimodal exercise program on the functional capacity of Parkinson's disease patients considering disease severity and gender

The purpose of this study was to investigate the effects of a multimodal exercise program (MEP) on the functional capacity of patients with Parkinson's disease (PD) according to disease severity and gender. Fourteen patients with PD participated in the study and were distributed into groups according to 1) stage of disease and 2) gender. Functional capacity was evaluated before and after 6 months of intervention. The overall PD patient group improved their coordination and strength. Men and women improved in strength performance after exercise. Men also improved on coordination. For severity of disease, the unilateral group improved in strength, while the bilateral group improved in strength, balance, coordination and the UPDRS-functional score. In conclusion, a MEP is efficient in improving components of functional capacity in patients with PD, especially in strength. Gender may be considered in the exercise program. Individuals in the bilateral disease group appeared to benefit more from exercise.

Sex differences in cerebral energy metabolism in Parkinson's disease: a phosphorus magnetic resonance spectroscopic imaging study

OBJECTIVE

To test the hypothesis that there are sex differences in cerebral energy metabolism in Parkinson's disease (PD).

METHODS

Phosphorus magnetic resonance spectroscopy ((31)P MRS) was used to determine high-energy phosphate (phosphocreatine and ATP) and low-energy phosphate (free phosphate) levels in the striatum and temporoparietal cortical gray matter (GM) in 10 men and 10 women with PD, matched for age at onset, disease duration, and UPDRS scores.

RESULTS

In the hemisphere more affected by PD, both ATP and high energy phosphate (HEP: phosphocreatine + ATP) content in striatum was 15% lower in men versus women with PD (p = .050 and p = .048, respectively). Similar decreases by 16% in ATP (p = .023) and 12% in HEP (p = .046) were observed in GM in men versus women with PD. In contrast, there were no detectable sex differences in ATP or HEP in healthy age-matched controls.

CONCLUSIONS

Men with PD have lower levels of ATP and high energy phosphate than women in brain regions affected by PD. These findings suggest that there may be a greater burden of mitochondrial dysfunction in PD in men versus women with PD.

Evidence for gender differences in cognition, emotion and quality of life in Parkinson's disease?

A number of gender differences have been documented in the incidence and symptomatology of the second most common age-related neurodegenerative disorder, idiopathic Parkinson's disease (PD). Overall, previous reports suggest a less frequent incidence and a more benign phenotype in women mainly in Western populations, which is thought to be mediated by estrogens in particular in early stages of the disease. Not only motor symptoms seem to underlie gender effects, but also non-motor symptoms such as psychiatric and cognitive impairments, which can often precede motor manifestation. However, reliable results for gender differences in PD in particular of cognitive function and emotion processing, having a major impact on quality of life, are lacking. Moreover, studies investigating gender effects in PD in these areas have revealed highly heterogeneous results. The present review summarizes findings of currently available studies on gender effects on neuropsychological tests covering major cognitive domains, emotion processing as well as quality of life in patients with PD. Overall, the occurrence of cognitive impairment in PD seems to be associated with male gender, though inconsistent results were shown in cognitive screening tests. Regarding emotion recognition, men with PD were found to be less accurate than women with PD at identifying fearful expressions, whereas vice versa results appeared in healthy subjects. Lower quality of life and greater disability were reported by women compared to men with PD, which corresponds with the results in healthy subjects. Several disease-specific mediators as well as the question of a general gender and age-related effect as observed in healthy individuals are discussed. Increased knowledge on possible gender effects in PD would provide an enhanced insight in underlying pathological mechanisms, and has potential implications for the diagnosis and treatment of PD.