Epidemiology of Parkinson disease in the city of Kolkata, India: a community-based study

Global prevalence and incidence of Young Onset Parkinson's disease: A systematic review and meta-analysis

BACKGROUND

There is a lack of enough evidence regarding the epidemiology of Young-onset Parkinson's disease (YOPD) which is needed by clinicians and healthcare policymakers.

AIM

Herein, in this systematic review and meta-analysis, we aimed to estimate the global prevalence and incidence rates of YOPD.

METHODS

We searched the literature in PubMed, Scopus, and Web of Science in May 2022. We included retrospective, prospective, cross-sectional observational population-based studies that reported the prevalence or incidence of PD in individuals younger than 40 years with known diagnostic criteria.

RESULTS

After two-step screening, 50 studies were eligible to be included in our study. The age-standardized prevalence of YOPD was 10.2 per 100,000 persons globally while it was 14.7 per 100,000 population in European countries. Age-standardized prevalence estimates for 5-year age bands showed that the YOPD prevalence estimates varied from 6.1 per 100,000 population in the group aged 20-24 to 16.1 per 100,000 population in the group aged 35-39. Also, the age-standardized incidence of YOPD was 1.3 per 100,000 person-years population worldwide and 1.2 per 100,000 person-years in the European population.

CONCLUSION

Based on this systematic review and meta-analysis, the overall prevalence of YOPD is 10.2 per 100,000 population, although estimates of the prevalence and incidence in low-income countries remain scarce. To improve monitoring and certain diagnoses of YOPD, healthcare providers and policymakers should be aware that much more effective tools are required.

Changes in Optimal Stimulation Frequency with Time for Gait Disturbances in Patients with PD after STN-DBS-A Longitudinal Study

Aim

To assess the changes in frequency parameters of STN-DBS stimulation over 6 months required to optimize gait in PD patients.

Methods

It's a single center, open label longitudinal study of PD patients after STN-DBS with gait disorders. Gait assessment using stand-walk-sit (SWS) test and freezing of gait (FOG) scores were done at baseline and after 6 months. Gait was assessed in five frequencies settings, that is, 60 Hz, 90 Hz, 130 Hz, 180 Hz and stimulation "OFF" during medication ON state. Voltage was maintained.

Results

Fifteen post-deep brain stimulation (DBS) patients were included. Mean duration after surgery was 3.73 ± 2.82 years. In SWS and FOG at baseline, five patients have good response at 180 Hz frequency, five at 130 Hz, one at 90 Hz, two patients at 60 Hz, one both 60 and 90 Hz, and one at both 90 and 180 HZ. And after 6 months out of the 13 patients who were able to perform the test, four patients had good response at 180 Hz frequency, four at 130 Hz, two at 90 Hz, one each for 60 Hz and battery OFF state, and one for both 130 Hz and 180 Hz. At 6 months, four patients had good response at the same frequency as baseline, while 11 patients have change in frequency from baseline.

Conclusion

Optimal frequency for gait varies in patients-both low and high frequency may be useful. Optimal frequency for improving gait changes over period of time. Regular assessment and changing frequency may improve gait after DBS.

A Role of β2-Adrenoreceptor Agonists Related to the Development of Parkinson's Disease

Background

Several studies have suggested the potential protective role of β2-adrenoreceptor agonist (β2AR-agonist) on the development of Parkinson's disease (PD). However, those could not reflect a different epidemiologic background in eastern countries. We explored β2AR-agonist's effect on PD development by controlling for smoking.

Materials and Methods

We used the Korean national sample cohort data (from 2002 to 2013) containing 1,025,340 participants (2.2% of the whole population). The subjects over 60 years were included. PD was defined based on the ICD-10 code, which should be diagnosed by neurologists. Atypical Parkinsonisms or ataxic disorders were excluded. We made Set 1 (from 2003 to 2007) and Set 2 (from 2003 to 2008) based on the exposure period for the sensitivity analysis. We observed whether PD had developed during the follow-up periods in each subset.

Results

The PD (Set 1, n = 742; Set 2, n = 699) and non-PD group (Set 1, n = 57,645; Set 2, n = 66,586) were collected. Old age, Medicaid, and asthma were risk factors, whereas smoking was a significant protective factor for PD development. The proportion of β2AR-agonist use was significantly higher in the PD group than in the non-PD group (Set 1, 3.6% vs. 2.4%; Set 2, 4.1% vs. 2.6%). β2AR-agonist use still was a risk factor in developing PD from the multiple logistic regression analysis.

Conclusions

β2-AR-agonist looked like a risk factor rather than a protective factor for PD development. Well-controlled studies reflecting various epidemiologic backgrounds are required to confirm the role of β2AR-agonist.

Apoptotic Factors and Mitochondrial Complexes Assist Determination of Strain-Specific Susceptibility of Mice to Parkinsonian Neurotoxin MPTP

Identification of genetic mutations in Parkinson's disease (PD) promulgates the genetic nature of disease susceptibility. Resilience-associated genes being unknown till date, the normal genetic makeup of an individual may be determinative too. Our earlier studies comparing the substantia nigra (SN) and striatum of C57BL/6J, CD-1 mice, and their F1-crossbreds demonstrated the neuroprotective role of admixing against the neurotoxin MPTP. Furthermore, the differences in levels of mitochondrial fission/fusion proteins in the SN of parent strains imply effects on mitochondrial biogenesis. Our present investigations suggest that the baseline levels of apoptotic factors Bcl-2, Bax, and AIF differ across the three strains and are differentially altered in SN following MPTP administration. The reduction in complex-I levels exclusively in MPTP-injected C57BL/6J reiterates mitochondrial involvement in PD pathogenesis. The MPTP-induced increase in complex-IV, in the nigra of both parent strains, may be compensatory in nature. The ultrastructural evaluation showed fairly preserved mitochondria in the dopaminergic neurons of CD-1 and F1-crossbreds. However, in CD-1, the endoplasmic reticulum demonstrated distinct luminal enlargement, bordering onto ballooning, suggesting proteinopathy as a possible initial trigger.The increase in α-synuclein in the pars reticulata of crossbreds suggests a supportive role for this output nucleus in compensating for the lost function of pars compacta. Alternatively, since α-synuclein over-expression occurs in different brain regions in PD, the α-synuclein increase here may suggest a similar pathogenic outcome. Further understanding is required to resolve this biological contraption. Nevertheless, admixing reduces the risk to MPTP by favoring anti-apoptotic consequences. Similar neuroprotection may be envisaged in the admixed populace of Anglo-Indians.

Parkinson's Disease and Wearable Technology: An Indian Perspective

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder. In India, an accurate number of PD patients remains uncertain owing to the unawareness of PD symptoms in the geriatric population and the large discrepancy between the number of PD patients and trained neurologists. Constructing additional neurological care centers along with using technology and integrating it into digital healthcare platforms will help reduce this burden. Use of technology in PD diagnosis and monitoring started in 1980s with invasive techniques performed in laboratories. Over the last five decades, PD technology has significantly evolved where now patients can track symptoms using their smartphones or wearable sensors. However, the use of such technology within the Indian population is non-existent primarily due to the cost of digital devices and limited technological capabilities of geriatric patients especially in rural areas. Other reasons include secure data transfers from patients to physicians and the general lack of awareness of wearables devices. Thus, creating a simple, cost-effective and inconspicuous wearable device would yield the highest compliance within the Indian PD patient population. Implementation of such technology will provide neurologists with wider outreach to patients in rural locations, remote monitoring and empirical data to titrate medication.

Differences in Neuronal Numbers, Morphology, and Developmental Apoptosis in Mice Nigra Provide Experimental Evidence of Ontogenic Origin of Vulnerability to Parkinson's Disease

Parkinson disease (PD) prevalence varies by ethnicity. In an earlier study, we replicated the reduced vulnerability to PD in an admixed population, using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-susceptible C57BL/6 J, MPTP-resistant CD-1 and their F1 crossbreds. In the present study, we investigated if the differences have a developmental origin. Substantia nigra was evaluated at postnatal days 2 (P2), P6, P10, P14, P18, and P22. C57BL/6 J mice had smaller nigra and fewer dopaminergic neurons than the CD-1 and crossbreds at P2, which persisted through development. A significant increase in numbers and nigral volume was observed across strains until P14. A drastic decline thereafter was specific to C57BL/6 J. CD-1 and crossbreds retained their numbers from P14 to stabilize with supernumerary neurons at adulthood. The neuronal size increased gradually to attain adult morphology at P10 in the resistant strains, vis-à-vis at P22 in C57BL/6 J. Accordingly, in comparison to C57BL/6 J, the nigra of CD-1 and reciprocal crossbreds possessed cytomorphological features of resilience, since birth. The considerably lesser dopaminergic neuronal loss in the CD-1 and crossbreds was seen at P2 and P14 and thereafter was complemented by attenuated developmental cell death. The differences in programmed cell death were confirmed by reduced TUNEL labelling, AIF, and caspase-3 expression. GDNF expression aligned with the cell death pattern at P2 and P14 in both nigra and striatum. Earlier maturity of nigra and its neurons appears to be better features that reflect as MPTP resistance at adulthood. Thus, variable MPTP vulnerability in mice and also differential susceptibility to PD in humans may arise early during nigral development.

Recalling the pathology of Parkinson's disease; lacking exact figure of prevalence and genetic evidence in Asia with an alarming outcome: A time to step-up

Parkinson's disease (PD) is the second most common and progressive neurodegenerative disease globally, with major symptoms like bradykinesia, impaired posture, and tremor. Several genetic and environmental factors have been identified but elucidating the main factors have been challenging due to the disease's complex nature. Diagnosis, prognosis, and management of such diseases are challenging and require effective targeted attention in developing countries. Recently, PD is growing rapidly in many crowded Asian countries as an alarming threat with inadequate knowledge of its prevalence, genetic architecture, and geographic distribution. This study gave an in-depth overview of the prevalence, incidence and genomic/genetics studies published so far in the Asian population. To the best of our knowledge, PD has increased significantly in several Asian countries, including China, South Korea, Japan, Thailand, and Israel over the past few years, requiring a greater level of care and attention. Genetic screening of families with PD at national levels and establishing an official database of PD cases are essential to get a comprehensive and conclusive view of the exact prevalence and genetic diversity of PD in the Asian population to properly manage and treat the disease.

Movement of prion-like α-synuclein along the gut-brain axis in Parkinson's disease: A potential target of curcumin treatment

A pathological hallmark of the neurodegenerative disorder, Parkinson's disease (PD), is aggregation of toxic forms of the presynaptic protein, α-synuclein in structures known as Lewy bodies. α-Synuclein pathology is found in both the brain and gastrointestinal tracts of affected individuals, possibly due to the movement of this protein along the vagus nerve that connects the brain to the gut. In this review, we discuss current insights into the spread of α-synuclein pathology along the gut-brain axis, which could be targeted for therapeutic interventions. The prion-like propagation of α-synuclein, and the clinical manifestations of gastrointestinal dysfunction in individuals living with PD, are discussed. There is currently insufficient evidence that surgical alteration of the vagus nerve, or removal of gut-associated lymphoid tissues, such as the appendix and tonsils, are protective against PD. Furthermore, we propose curcumin as a potential candidate to prevent the spread of α-synuclein pathology in the body by curcumin binding to α-synuclein's non-amyloid β-component (NAC) domain. Curcumin is an active component of the food spice turmeric and is known for its antioxidant, anti-inflammatory, and potentially neuroprotective properties. We hypothesize that once α-synuclein is bound to curcumin, both molecules are subsequently excreted from the body. Therefore, dietary supplementation with curcumin over one's lifetime has potential as a novel approach to complement existing PD treatment and/or prevention strategies. Future studies are required to validate this hypothesis, but if successful, this could represent a significant step towards improved nutrient-based therapeutic interventions and preventative strategies for this debilitating and currently incurable disorder.

A Systematic Review and Meta-analysis of Prevalence of Epilepsy, Dementia, Headache, and Parkinson Disease in India

Background

There are wide variations reported in the prevalence rates of common neurological disorders in India leading to huge treatment gap. There is no comprehensive systematic review reporting prevalence of common neurological conditions affecting Indians which is essential for developing and aligning health services to meet patient care.

Objectives

The aim of this study was to perform a systematic review and meta-analysis of prevalence of epilepsy, dementia, headache, and Parkinson's disease (PD) in India from 1980 to 2019.

Methods and Materials

We performed a bibliographic systematic search in PubMed and Google Scholar along with manual search for peer-reviewed cross-sectional studies and community-based surveys reporting prevalence of epilepsy, dementia, headache, and PD in India from January 1980 to July 2019. Meta-analysis was performed adopting a random-effects model using "Metafor" package in R.

Results

The systematic review and meta-analysis included 50 studies [epilepsy (n = 22), dementia (n = 19), headache (n = 6), and PD (n = 3)] including a total of 179,1541 participants of which 5,890 were diagnosed with epilepsy, 1,843 with dementia, 914 with headache, and 121 were diagnosed with PD. The pooled prevalence of epilepsy was 4.7 per 1,000 population (95% CI: 3.8-5.6) with high heterogeneity (P < 0.01, I² = 98%). The prevalence of dementia was found to be 33.7 per 1,000 population (95% CI: 19.4-49.8) (P = 0, I² = 100%). The pooled prevalence of headache and PD were found to be 438.8 per 1,000 population (95% CI: 287.6-602.3) (P < 0.0001, I² = 97.99%), and 0.8 per 1,000 population (95%CI: 0.4-1.3) (P < 0.01, I² = 95%), respectively.

Conclusions

The findings could be used for appropriate policy measures and targeted treatments for addressing these conditions.

Epidemiology of Parkinson's Disease in Rural Gujarat, India

INTRODUCTION

In India, there have been only few published studies of Parkinson's disease (PD) showing a wide range of prevalence. We conducted this study to determine the prevalence of PD in the rural population of Gujarat, in the western region of India.

METHODS

This cross-sectional descriptive study was conducted in the villages of Anand, a district of Gujarat, India, between September 2019 and February 2020. This study used a multistep approach including a screening questionnaire and video recording followed by clinical examination by a neurologist, laboratory evaluation, and brain imaging to evaluate patients with PD.

RESULTS

A total population of 18,896 was screened. The overall crude prevalence of PD was 42.3 per 100,000, and the prevalence over the age of 60 was 308.9 per 100,000 which showed the trend of increasing disease prevalence with age. Their mean duration of illness was 39.3 ± 27.3 months, and more than half of patients with PD had multiple associated nonmotor symptoms and nearly one-third had comorbid anxiety or depression. Environmental factors are important in the pathogenesis of PD, but there was no clear association between patients with PD and certain variables including consumption of well water, exposure to pesticides or other toxins, smoking cigarettes, and drinking alcohol or coffee in our study.

CONCLUSIONS

The present study showed the current epidemiological data of PD from Gujarat, in western India. Further studies across different regions in India need to be encouraged for better understanding of PD prevalence in the Indian population.

Prevalence of major neurological disorders in predominantly rural northwest India

Background

Epidemiological studies based on hospital population, geographic isolates, smaller population, and focused groups provide valuable information on the pattern of diseases, but do not reflect on the true prevalence rates or the changing trends of disease over a period of time in different communities. The present study was undertaken to determine the prevalence and pattern of various neurological disorders in Himachal Pradesh.

Methodology

Study was carried out in urban and rural population of district Kangra of Himachal Pradesh. A proportional representation was given to each area in the allocation of sample size as per probability proportional to size (PPS) method using a two-phase design: 1) A screening phase and 2) a clinical evaluation phase. All subjects were screened and a subset (screen positive and 10% of screen negative) was identified for the detailed clinical evaluation after screening. A standardized screening battery (NIMHANS protocol) was used for this purpose. An individual was confirmed as a case of neurological disorder only after clinical evaluation.

Results

A total of 260 (out of 10,000 studied) individuals were found positive for neurological disorders yielding a crude prevalence of 2.6%. The crude prevalence for rural areas was found to be 2.28% (206/9000), whereas the crude prevalence in urban area was found to be 5.4% (54/1000). Migraine was the most common disorder.

Conclusion

In view of the high crude prevalence of major neurological disorders, there is a need to develop capacity among healthcare professionals regarding them.

Functional association between NUCKS1 gene and Parkinson disease: A potential susceptibility biomarker

Several Genome Wide Association Studies (GWASs) have reported that PARK16 gene locus possibly regulate the risk of Parkinson's disease (PD). It contains functionally interesting candidate genes for PD, regulated by number of SNPs. In present study rs823093 polymorphism in NUCKS1 gene has been evaluated as significant performer in PD though its mechanism is not yet known. Here various regulatory and functional analyses were performed using computational tools and information from databases. The rs823093 variant was predicted to locate in enhancer histone marks in blood and have strong transcription in various parts of brain, heart, kidney and liver. PhenoScanner (a database of human genotype-phenotype associations) identified significant associations of this variant with many other diseases and phenotypic conditions as well. Gene expression analysis shows significant association with multiple human tissues and multiple genes together with NUCKS1. Further, the post mortem brain samples showed diverse expressions of NUCKS1 gene in PD patients compared to healthy samples. Besides, the metabolite analysis shows significant association with serotonin a known neurotransmitter, and other 15 metabolites. In addition, NUCKS1 also showed co-expression with ZNF43 and PLIN1 genes involved in cell cycle regulation presume their association in PD. Thus, these data links NUCKS1 gene as a potential disease susceptibility biomarker for PD.

Divergent Expression Patterns of Drp1 and HSD10 in the Nigro-Striatum of Two Mice Strains Based on their MPTP Susceptibility

Alterations in the basal ganglia circuitry are critical events in the pathophysiology of Parkinson's disease (PD). We earlier compared MPTP-susceptible C57BL/6J and MPTP-resistant CD-1 mice to understand the differential prevalence of PD in different ethnic populations like Caucasians and Asian-Indians. The MPTP-resistant CD-1 mice had 33% more nigral neurons and lost only 15-17% of them following MPTP administration. In addition to other cytomorphological features, their basal ganglia neurons had higher calcium-buffering protein levels. During disease pathogenesis as well as in MPTP-induced parkinsonian models, the loss of nigral neurons is associated with reduction in mitochondrial complex-1. Under these conditions, mitochondria respond by undergoing fusion or fission. 17β-hydroxysteroid type 10, i.e., hydroxysteroid dehydrogenase10 (HSD10) and dynamin-related peptide1 (Drp1) are proteins involved in mitochondrial hyperfusion and fission, respectively. Each plays an important role in mitochondrial structure and homeostasis. Their role in determining susceptibility to the neurotoxin MPTP in basal ganglia is however unclear. We studied their expression using immunohistochemistry and Western blotting in the dorsolateral striatum, ventral tegmental area, and substantia nigra pars compacta (SNpc) of C57BL/6J and CD-1 mice. In the SNpc, which exhibits more neuron loss following MPTP, C57BL/6J had higher baseline Drp1 levels; suggesting persistence of fission under normal conditions. Whereas, HSD10 levels increased in CD-1 following MPTP administration. This suggests mitochondrial hyperfusion, as an attempt towards neuroprotection. Thus, the baseline differences in HSD10 and DRP1 levels as well as their contrasting MPTP-responses may be critical determinants of the magnitude of neuronal loss/survival. Similar differences may determine the variable susceptibility to PD in humans.

Admixing MPTP-resistant and MPTP-vulnerable mice enhances striatal field potentials and calbindin-D28K expression to avert motor behaviour deficits

Asian-Indians are less vulnerable to Parkinson's disease (PD) than the Caucasians. Their admixed populace has even lesser risk. Studying this phenomenon using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-susceptible C57BL/6J, MPTP-resistant CD-1 and their resistant crossbred mice revealed differences in the nigrostriatal cyto-molecular features. Here, we investigated the electrophysiological and behavioural correlates for differential MPTP-susceptibility and their outcome upon admixing. We recorded local field potentials (LFPs) from dorsal striatum and assessed motor co-ordination using rotarod and grip strength measures. Nigral calbindin-D28K expression, a regulator of striatal activity through nigrostriatal projections was evaluated using immunohistochemistry. The crossbreds had significantly higher baseline striatal LFPs. MPTP significantly increased the neuronal activity in delta (0.5-4 Hz) and low beta (12-16 Hz) ranges in C57BL/6J; significant increase across frequency bands till high beta (0.5-30 Hz) in CD-1, and caused no alterations in crossbreds. MPTP further depleted the already low nigral calbindin-D28K expression in C57BL/6J. While in crossbreds, it was further up-regulated. MPTP affected the rotarod and grip strength performance of the C57BL/6J, while the injected CD-1 and crossbreds performed well. The increased striatal β-oscillations are comparable to that in PD patients. Higher power in CD-1 may be compensatory in nature, which were also reported in pre-symptomatic monkeys. Concurrent up-regulation of nigral calbindin-D28K may assist maintenance of striatal activity by buffering calcium overload in nigra. Thus, preserved motor behaviour in PD reminiscent conditions in CD-1 and crossbreds complement compensated/unaffected striatal LFPs. Similar electrophysiological correlates and cytomorphological features are envisaged in human phenomenon of differential PD prevalence, which are modulated upon admixing.

Biomarkers for detection, prognosis and therapeutic assessment of neurological disorders

Neurological disorders have aroused a significant concern among the health scientists globally, as diseases such as Parkinson's, Alzheimer's and dementia lead to disability and people have to live with them throughout the life. Recent evidence suggests that a number of environmental chemicals such as pesticides (paraquat) and metals (lead and aluminum) are also the cause of these diseases and other neurological disorders. Biomarkers can help in detecting the disorder at the preclinical stage, progression of the disease and key metabolomic alterations permitting identification of potential targets for intervention. A number of biomarkers have been proposed for some neurological disorders based on laboratory and clinical studies. In silico approaches have also been used by some investigators. Yet the ideal biomarker, which can help in early detection and follow-up on treatment and identifying the susceptible populations, is not available. An attempt has therefore been made to review the recent advancements of in silico approaches for discovery of biomarkers and their validation. In silico techniques implemented with multi-omics approaches have potential to provide a fast and accurate approach to identify novel biomarkers.

New endemic familial parkinsonism in south Moravia, Czech Republic and its genetical background

An increased prevalence of familial neurodegenerative parkinsonism or cognitive deterioration was recently found in a small region of southeastern Moravia.The aim of the study was to assess the genetic background of this familial disease.Variants in the ADH1C, EIF4G1, FBXO7, GBA + GBAP1, GIGYF2, HTRA2, LRRK2, MAPT, PRKN, DJ-1, PINK1, PLA2G6, SNCA, UCHL1, VPS35 genes were examined in 12 clinically positive probands of the pedigree in which familial atypical neurodegenerative parkinsonism was identified in previous epidemiological studies. Libraries were sequenced by massive parallel sequencing (MPS) on the Personal Genome Machine (PGM; Ion Torrent). Data were analyzed using Torrent Suite and IonReporter software. All variants were then verified and confirmed by Sanger sequencing.We identified 31 rare heterozygous variants: 11 missense variants, 3 synonymous variants, 8 variants in the UTR region, and 9 intronic variants. Six variants (rs1801334, rs33995883, rs35507033, rs781737269, rs779760087, and rs63750072) were evaluated as pathogenic by at least one in-silico predictor.No single "founder" pathogenic variant associated with parkinsonism has been found in any of the probands from researched pedigree. It may rather be assumed that the familial occurrence of this disease is caused by the combined influence of several "small-effect" genetic variants that accumulate in the population with long-lasting inbreeding behavior.

The increasing prevalence of Parkinson's disease in Estonia

OBJECTIVES

A previous epidemiological study of Parkinson's disease (PD) in the county of Tartu, Estonia, found an adjusted prevalence rate of 152/100 000 persons. We aimed to determine PD prevalence almost 20 years later, as well as evaluate any dynamic changes in disease frequency compared to the first study.

METHODS

A cross-sectional, community-based study was conducted over 2010-2016 in the county of Tartu, Estonia. Multiple case-finding sources, including information from neurologists, family doctors, the local PD Society, nursing institutions, and the database of the Estonian Health Insurance Fund were used to identify patients with PD of all ages.

RESULTS

Total crude PD prevalence was 283 and age-adjusted prevalence (standardized to the 2014 age structure of the Estonian population) 314/100 000. No significant differences in age-adjusted prevalence rates were found between men and women, nor people living in urban and rural areas. After adjustment to the same standard population used in the previous prevalence study, the overall age-adjusted prevalence rate was 197/100 000. Patients in the current study were older and often had a more severe form of PD and a longer disease duration, compared to those reported in the first epidemiological study 20 years ago.

CONCLUSIONS

The age-specific crude rates in oldest age-groups have risen substantially, and the age-adjusted prevalence has moderately increased compared to 20 years ago in Estonia. We hypothesize that the increased life expectancy of the Estonian population and improved diagnosis of PD contributed most to the increase in disease frequency.

Sex differences in Parkinson's disease: Features on clinical symptoms, treatment outcome, sexual hormones and genetics

Parkinson's disease (PD) is the second most frequent age-related neurodegenerative disorder. Sex is an important factor in the development of PD, as reflected by the fact that it is more common in men than in women by an approximate ratio of 2:1. Our hypothesis is that differences in PD among men and women are highly determined by sex-dependent differences in the nigrostriatal dopaminergic system, which arise from environmental, hormonal and genetic influences. Sex hormones, specifically estrogens, influence PD pathogenesis and might play an important role in PD differences between men and women. The objective of this review was to discuss the PD physiopathology and point out sex differences in nigrostriatal degeneration, symptoms, genetics, responsiveness to treatments and biochemical and molecular mechanisms among patients suffering from this disease. Finally, we discuss the role estrogens may have on PD sex differences.

Baseline striatal and nigral interneuronal protein levels in two distinct mice strains differ in accordance with their MPTP susceptibility

Epidemiological studies reveal an ethnicity-based bias in prevalence of Parkinson's disease (PD), deriving from the differences that exist between Caucasians and African or Asian populations. Experimental mice models provide a scope to analyse the cellular mechanisms of differential susceptibility to PD. C57BL/6J mice, for instance, are more susceptible to MPTP-induced Parkinsonism whereas CD-1 mice are resistant. In PD-pathogenesis, interneuronal contribution is also likely, although they comprise only 5-10% of the striatal cells. The interneurons harbour calcium binding proteins, like calretinin (Cal-R) and parvalbumin (PV), which are crucial in Ca²⁺ homeostasis for preventing calcium-induced excitotoxicity. GAD-67-immunoreactive interneurons are the other prominent set of GABAergic interneurons. In PD, dopamine loss up-regulates GAD-67 expression in striatal projection neurons and other basal ganglia circuit. We studied the possible contribution of interneurons in determining variable susceptibility by assessing the expression of calretinin, PV and GAD-67 in both striatum and substantia nigra pars compacta (SNpc) in two distinct mice strains, i.e. C57BL/6J and CD-1 under normal conditions, using unbiased stereology for quantification of immunoreactive cells and immunoblotting. The vulnerable C57BL/6J had lesser basal parvalbumin expression in both nigra and striatum whereas the calretinin levels were low only in the striatum. GAD-67 expression showed no perceptible differences in the striatum or SNpc of either of the strains. Differential expression of calcium buffering/binding proteins under normal physiological condition proffers a role for interneurons in the differential susceptibility to PD. Thus, even the baseline susceptibility indices i.e. without using the neurotoxin; can provide vital mechanistic insights into PD pathogenesis.

Reporting of ethics in peer-reviewed verbal autopsy studies: a systematic review

Introduction

Verbal autopsy (VA) is a method that determines the cause of death by interviewing a relative of the deceased about the events occurring before the death, in regions where medical certification of cause of death is incomplete. This paper aims to review the ethical standards reported in peer-reviewed VA studies.

Methods

A systematic review of Medline and Ovid was conducted by two independent researchers. Data were extracted and analysed for articles based on three key areas: Institutional Review Board (IRB) clearance and consenting process; data collection and management procedures, including: time between death and interview; training and education of interviewer, confidentiality of data and data security; and declarations of funding and conflict of interest.

Results

The review identified 802 articles, of which 288 were included. The review found that 48% all the studies reported having IRB clearance or obtaining consent of participants. The interviewer training and education levels were reported in 62% and 21% of the articles, respectively. Confidentiality of data was reported for 14% of all studies, 18% did not report the type of respondent interviewed and 51% reported time between death and the interview for the VA. Data security was reported in 8% of all studies. Funding was declared in 63% of all studies and conflict of interest in 42%. Reporting of all these variables increased over time.

Conclusions

The results of this systematic review show that although there has been an increase in ethical reporting for VA studies, there still remains a large gap in reporting.

Epidemiology of Parkinson's Disease-East Versus West

Background

The cause of PD at present remains unknown. A number of epidemiological studies have been conducted across the globe to ascertain the disease burden and the possible risk factors. In this review, we analyze the various studies from East and West with an aim to observe the important similarities and differences in the disease occurrence and risk factor profile.

Methods

A comprehensive search of descriptive and analytical epidemiological studies was undertaken. The descriptive studies and meta-analysis providing the standardised population rates were selected. The demographics, ethnicity and geographical differences between East and West were analysed. In analytical epidemiology, more established and well-studied non-genetic risk factors for PD were reviewed utilising the prospective cohort studies, case control studies and meta-analysis where available.

Results and Conclusion

PD is more common with increasing age and shows male predominance, which is more obvious in Western studies. The PD prevalence and incidence rates are slightly lower in the East compared to the West. Incidence studies on different ethnic populations in the same country have also found a lower occurrence of PD amongst Easterners compared to Westerners. Setting methodological differences aside, studies from East and West suggest a role for both environmental and genetic risk factors in PD causation. Smoking, caffeine intake and pesticide exposure are well-established risk factors across regions. There is a robust data for dairy product consumption, urate levels and physical activity in the West while studies on certain risk factors like head injury and alcohol show conflicting and mixed results.

Tobacco Use, Oral Health, and Risk of Parkinson's Disease

Few studies have investigated the associations between use of Swedish moist snuff (snus), associated poor oral health, and risk of Parkinson's disease (PD). We followed 20,175 participants who were free of PD in 1973-1974 in Uppsala, Sweden, until the end of 2012. We used Cox proportional hazards regression models to estimate hazard ratios and corresponding 95% confidence intervals for the associations between tobacco use, oral health indicators, and PD risk. We found that tobacco use was associated with a lower risk of PD in males. Compared with males who never used any tobacco daily, pure ever tobacco smokers, pure ever snus users, and combined users had adjusted hazard ratios of 0.68 (95% confidence interval (CI): 0.49, 0.93; n = 83), 0.51 (95% CI: 0.27, 0.95; n = 11), and 0.21 (95% CI: 0.07, 0.67; n = 3), respectively. No association was observed for number of teeth, dental plaque, or detectable oral mucosal lesions and PD risk, although there was a suggestive association with Candida-related oral mucosal lesions in males (hazard ratio = 1.56, 95% CI: 0.92, 2.65; P = 0.098). Use of snus is associated with a lower risk of PD in males, while poor oral health seems not to be associated with PD occurrence.

Admixing of MPTP-Resistant and Susceptible Mice Strains Augments Nigrostriatal Neuronal Correlates to Resist MPTP-Induced Neurodegeneration

Disease genetics in admixed populations like Hispanic-Americans, African-Americans, etc. are gaining importance due to high disease burden in them. Furthermore, epidemiological studies conclusively prove ethnicity-based differential prevalence of Parkinson's disease (PD), since the American-Caucasians are more susceptible than Asian-Indians and Africans. Contradictorily, Anglo-Indians, an admixture of Europeans and Asian-Indians are five-times less susceptible than Indians. We evaluated the neural basis of this phenomenon using the cytomorphological features of susceptibility to nigrostriatal neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The nigral dopaminergic neuronal numbers, their size and tyrosine hydroxylase (TH), PitX3 and Nurr1 expression were compared in MPTP-susceptible C57BL/6J mice, MPTP-resistant CD-1 mice and their crossbreds using stereology, morphometry and densitometry. Apoptotic index was evaluated by TUNEL-assay and caspase-3 expression. Striatal volume, TH and glial derived neurotrophic factor (GDNF) expression were studied. The normal CD-1 and crossbreds had significantly more, although smaller, nigral dopaminergic neurons than C57BL/6J, and a larger striatum. The crossbreds had higher TH, Nurr1 and PitX3 levels. MPTP administration caused loss of ~50-60 % nigral dopaminergic neurons in C57BL/6J and ~15 % in CD-1, but none in crossbreds. MPTP-induced cellular shrinkage in C57BL/6J was contrasted by nuclear enlargement without somal alterations in resistant strains. MPTP lowered the striatal TH and GDNF in C57BL/6J. Elevated striatal GDNF in CD-1 and crossbreds could be of compensatory nature and complemented the reduced nigral caspase-3 expression to attenuate and/or block apoptosis. Similar neural correlates of resilience are envisaged in the Anglo-Indian population. Thus, we present the core neuroanatomical features of resilience against PD and evidence for ethnicity-based differential prevalence.

Differential expression of calbindin in nigral dopaminergic neurons in two mice strains with differential susceptibility to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

Parkinson's disease (PD) affects the A9 dopaminergic (DA) neurons of substantia nigra pars compacta (SNpc) whereas other DA neuronal subtypes are spared. The role of calbindin in this differential vulnerability has been long elicited, and is seen in the MPTP induced mice models of PD. A peculiar feature of mice models is the strain specific differences in the susceptibility to MPTP. Here, calbindin-D28K expression in DA neurons of SNpc of MPTP susceptible C57BL/6 mice and MPTP resistant CD-1 mice was studied as a susceptibility marker of degeneration. Unbiased stereological estimation of immunoperoxidase stained midbrain sections revealed significantly higher number of calbindin immunoreactive cells in SNpc of CD-1 mice compared to that of C57BL/6 strain. Western blotting showed minimal differences in the levels. Calbindin-tyrosine hydroxylase immunofluorescence co-labeling was performed to map the calbindin immunoreactive DA neurons in SNpc and ventral tegmental area (VTA) and to quantify the calbindin expression at cellular level. While the levels were comparable in VTA of both mice strains, the SNpc of CD-1 mice showed significantly higher calbindin expression. Within the SNpc, the medial and dorsal subdivisions showed higher calbindin expression in CD-1. The expression in the ventrolateral SNpc of both strains remained comparable. Our observations clearly point at overall higher levels and sizeable percentage of cells expressing more calbindin in SNpc of CD-1 mice, which might confer neuroprotection against MPTP, while its lower expression makes C57BL/6 mice more susceptible. Similar mechanism may be attributed to the phenomenon of differential prevalence of PD in different ethnic populations.

Update on deep brain stimulation in Parkinson's disease

Deep brain stimulation (DBS) is considered a safe and well tolerated surgical procedure to alleviate Parkinson’s disease (PD) and other movement disorders symptoms along with some psychiatric conditions. Over the last few decades DBS has been shown to provide remarkable therapeutic effect on carefully selected patients. Although its precise mechanism of action is still unknown, DBS improves motor functions and therefore quality of life. To date, two main targets have emerged in PD patients: the globus pallidus pars interna and the subthalamic nucleus. Two other targets, the ventralis intermedius and zona incerta have also been selectively used, especially in tremor-dominant PD patients. The main indications for PD DBS have traditionally been motor fluctuations, debilitating medication induced dyskinesias, unpredictable “off time” state, and medication refractory tremor. Medication refractory tremor and intolerable dyskinesia are potential palliative indications. Besides aforementioned targets, the brainstem pedunculopontine nucleus (PPN) is under investigation for the treatment of ON-state freezing of gait and postural instability. In this article, we will review the most recent literature on DBS therapy for PD, including cutting-edge advances and data supporting the role of DBS in advanced neural-network modulation.

Comparison of frequencies of non motor symptoms in Indian Parkinson's disease patients on medical management versus deep brain stimulation: A case-control study

BACKGROUND

Non motor symptoms (NMS) of idiopathic Parkinson's disease (PD) are a major cause of disability and recognition of these symptoms and treatment is important for comprehensive health care. Deep brain stimulation of bilateral subthalamic nucleus deep brain stimulation (STN DBS) has been shown to improve motor symptoms in PD and effects on NMS are unknown. To investigate the NMS among PD patients who underwent STN DBS.

METHODS

We recruited prospectively 56 patients with PD, who had undergone bilateral STN DBS and 53 age and duration of illness matched PD patients on dopaminergic therapy (controls). NMS were assessed using 30 item questionnaire NMS Quest. These questions evaluated 9 domains, gastrointestinal, urinary, cardiovascular, sexual, cognition (apathy/attention/memory), anxiety/depression, hallucinations/delusions, sleep and miscellaneous. Comparison was done on individual symptoms as well as in various domains. This study was carried at Nizam's Institution of Medical Sciences and study period was from January 2011 to December 2012.

RESULTS

Patients who underwent STN DBS had a significantly lower mean total score on NMS quest (6.7 ± 3.8) compared to controls (8.4 ± 3.7) (P < 0.00100). Symptoms in the domains of cardiovascular, gastrointestinal, sleep were significantly less frequent while sexual disturbances were significantly more frequent among patients compared to controls. On individual symptom analysis, nocturia  (P < 0.00010), unexplained pains (P < 0.00010), nausea and vomiting, constipation, lightheadedness, depression, and insomnia were less prevalent, while sexual disturbances were significantly more common in STN DBS group compared to controls.

CONCLUSION

Bilateral STN DBS not only improves the motor symptoms but also improves many NMS in PD patients.

Neuroscience of exercise: from neurobiology mechanisms to mental health

The neuroscience of exercise is a growing research area that is dedicated to furthering our understanding of the effects that exercise has on mental health and athletic performance. The present study examined three specific topics: (1) the relationship between exercise and mental disorders (e.g. major depressive disorder, dementia and Parkinson's disease), (2) the effects of exercise on the mood and mental health of athletes, and (3) the possible neurobiological mechanisms that mediate the effects of exercise. Positive responses to regular physical exercise, such as enhanced functional capacity, increased autonomy and improved self-esteem, are frequently described in the recent literature, and these responses are all good reasons for recommending regular exercise. In addition, physical exercise may improve both mood and adherence to an exercise program in healthy individuals and might modulate both the performance and mental health of athletes. Exercise is associated with the increased synthesis and release of both neurotransmitters and neurotrophic factors, and these increases may be associated with neurogenesis, angiogenesis and neuroplasticity. This review is a call-to-action that urges researchers to consider the importance of understanding the neuroscience of physical exercise and its contributions to sports science.

Cell based therapies in Parkinson's Disease

Parkinson’s disease (PD) is the second most common neurodegenerative disorder after Alzheimer’s disease. It is characterized by bradykinesia, hypokinesia/ akinesia, rigidity, tremor, and postural instability, caused by dopaminergic (DA) striatal denervation. The prevalence of PD increases from 50 years of age with steep rise after age 60 years. Current treatment of PD relies heavily on replacing lost dopamine either with its precursor L-dopa or dopamine agonists (ropinirole, pramipexole, bromocriptine, lisuride etc). Other pharmacological measures like catechol-O-methyltrasferase (COMT) inhibitors like entacopone, telcapone and monoamine oxidase B (MAO-B) inhibitors like selegiline and rasagiline are also useful, while L-dopa remains the gold standard in the treatment of PD. Emerging therapies are focusing on cell based therapeutics derived from various sources.

Gender-related protection from or vulnerability to severe CNS diseases: gonado-structural and/or gonado-activational? A meta-analysis of relevant epidemiological studies

BACKGROUND

A vast scientific literature has dealt with gender-specific risk for brain disorder. That field is evolving toward a consensus to the effect that the estrogen hormone family is outstandingly and uniquely neuroprotective. However, the epidemiology relevant to this general outlook remains piecemeal.

METHOD

The present investigation strategically formats the relevant epidemiological findings around the world in order to quantitatively meta-analyze gender ratio of risk for a variety of relevant severe central nervous system (CNS) diseases at all three gonadal stages of the life cycle, pre pubertal, post adolescent/pre menopausal, and post menopausal.

RESULTS

The data quantitatively establish that (1) no single epidemiological study should be cited as evidence of gender-specific neuroprotection against the most common severe CNS diseases because the gender-specific risk ratios are contradictory from one study to the other; (2) risk for severe CNS disease is indeed significantly gender-specific, but either gender can be protected: it depends on the disease, not at all on the age bracket.

CONCLUSION

Our assay of gender-specific risk for severe brain disease around the world has not been able to support the idea according to which any one gender-prevalent gonadal steroid hormone dominates as a neuroprotective agent at natural concentrations.

The prevalence of Parkinson's disease: a systematic review and meta-analysis

Parkinson's Disease (PD) is a common neurodegenerative disorder. We sought to synthesize studies on the prevalence of PD to obtain an overall view of how the prevalence of this disease varies by age, by sex, and by geographic location. We searched MEDLINE and EMBASE for epidemiological studies of PD from 1985 to 2010. Data were analyzed by age group, geographic location, and sex. Geographic location was stratified by the following groups: 1) Asia, 2) Africa, 3) South America, and 4) Europe/North America/Australia. Meta-regression was used to determine whether a significant difference was present between groups. Forty-seven studies were included in the analysis. Meta-analysis of the worldwide data showed a rising prevalence of PD with age (all per 100,000): 41 in 40 to 49 years; 107 in 50 to 59 years; 173 in 55 to 64 years; 428 in 60 to 69 years; 425 in 65 to 74 years; 1087 in 70 to 79 years; and 1903 in older than age 80. A significant difference was seen in prevalence by geographic location only for individuals 70 to 79 years old, with a prevalence of 1,601 in individuals from North America, Europe, and Australia, compared with 646 in individuals from Asia (P < 0.05). A significant difference in prevalence by sex was found only for individuals 50 to 59 years old, with a prevalence of 41 in females and 134 in males (P < 0.05). PD prevalence increases steadily with age. Some differences in prevalence by geographic location and sex can be detected.

Profile of levodopa-induced dyskinesia in patients of Parkinson's disease: a record based study

OBJECTIVES

Levodopa-induced dyskinesia (LID) is one of the most disabling complications of long-term pharmacotherapy of Parkinson's disease (PD). The objective of our study was to examine the clinical profile and determinants of severity of LID in Indian PD patients on levodopa therapy.

METHODS

Retrospective analysis of records of PD patients with LID was performed. All patients were on levodopa and carbidopa combination. Records of subjects with complete information about disease profile, drug intake, and dyskinesia were analyzed. Characterization of LID was based on responses to part IV of unified Parkinson's disease rating scale (UPDRS).

RESULTS

Records of 42 patients (M∶F  =  4·6∶1) were analyzed. The median Hoehn and Yahr (H&Y) stage was 2·5 while median duration of levodopa therapy was 6·16 years (range: 1·91-14·58). Early morning dystonia was reported by 97·6% of the patients. Patients treated with ≧2 concomitant PD medication reported a significantly lower median UPDRS IV A score compared to patients treated with <2 number of concomitant drugs. A trend toward a lower UPDRS IV A score was associated with use of dopamine agonists (DA). Patients with H&Y score ≧3 had a significantly higher median total UPDRS IV A score than patients with H&Y score <3.

DISCUSSION

Early morning dystonia might be more common among Indian patients of LID. Use of a higher number of concomitant PD medications alongside levodopa is associated with a reduced severity of dyskinesia, even on prolonged use. Levodopa-induced dyskinesia is not only a drug-related phenomenon but the stage of PD itself also affects the dyskinesia severity.

Dysphagia as a risk factor for mortality in Niemann-Pick disease type C: systematic literature review and evidence from studies with miglustat

Niemann-Pick disease type C (NP-C) is a rare neurovisceral disease characterised by progressive neurological deterioration and premature death, and has an estimated birth incidence of 1:120,000. Mutations in the NPC1 gene (in 95% of cases) and the NPC2 gene (in approximately 4% of cases) give rise to impaired intracellular lipid metabolism in a number of tissues, including the brain. Typical neurological manifestations include vertical supranuclear gaze palsy, saccadic eye movement abnormalities, cerebellar ataxia, dystonia, dysmetria, dysphagia and dysarthria. Oropharyngeal dysphagia can be particularly problematic as it can often lead to food or fluid aspiration and subsequent pneumonia. Epidemiological data suggest that bronchopneumonia subsequent to food or fluid aspiration is a major cause of mortality in NP-C and other neurodegenerative disorders. These findings indicate that a therapy capable of improving or stabilising swallowing function might reduce the risk of aspiration pneumonia, and could have a positive impact on patient survival. Miglustat, currently the only approved disease-specific therapy for NP-C in children and adults, has been shown to stabilise key neurological manifestations in NP-C, including dysphagia. In this article we present findings from a systematic literature review of published data on bronchopneumonia/aspiration pneumonia as a cause of death, and on the occurrence of dysphagia in NP-C and other neurodegenerative diseases. We then examine the potential links between dysphagia, aspiration, pneumonia and mortality with a view to assessing the possible effect of miglustat on patient lifespan.

A case control study of women with Parkinson's disease and their fertility characteristics

BACKGROUND

Parkinson disease (PD) is less common in women and studies have shown that oestrogen is protective to dopaminergic neurons in primate models. The findings in clinical and epidemiological studies have not clearly established this observation. This study was undertaken to evaluate associations of reproductive characteristics in a population with higher fertility and risk of PD among women.

METHODS

Trained interviewers used structured interviews to obtain information about demographic characteristics and reproductive history from women subjects with PD. An equal number of healthy age matched female controls were also studied to compare their reproductive characteristics with women with PD.

RESULTS

We recruited 81 consecutive women with PD and age matched healthy women controls. Mean age at interview was 55.89 ± 10.07 years for women with PD, 55.05 ± 10.53 years for controls. Significant positive correlation was observed with cumulative length of pregnancy (r=0.32; p=0.003), age at menopause (r=0.55; p=0.001) and length of fertile life with age of onset of PD (r=0.27; p=0.02). Gravidity (r=0.26; p=0.02) and parity (r=0.35; p=0.001) also correlated positively with age at onset.

CONCLUSION

The onset of PD is delayed in women with higher number of pregnancies, longer fertile life and longer cumulative length of pregnancies. This could also explain the epidemiological observations of lower incidence of PD in women and the protective role of estrogens.

'We call it the shaking illness': perceptions and experiences of Parkinson's disease in rural northern Tanzania

Background

Parkinson disease (PD) causes physical disability that negatively affects the quality of life of the sufferer's and their families. There are no Parkinson's disease (PD) social science studies published from Africa. This paper presents findings from a qualitative research study on how PD is perceived and treated in a population of approximately 161,000 within a demographic surveillance site in rural Tanzania.

Methods

We conducted in-depth interviews with 28 PD sufferers, 28 carers, 4 health workers and 2 traditional healers. In addition, 6 focus group discussions were conducted in 3 villages to investigate wider community views of PD.

Results

PD sufferers expressed frustration with the physical, psychological, social and economic consequences of the illness. Feelings of a diminished quality of life characterised by dependency, stigma and social isolation were common. Additionally, a handful of male sufferers related their sexual incompetence to the illness. Carers complained of lost income opportunities and social isolation resulting from caring for sufferers. Misconceptions about the cause, symptoms and appropriated PD treatment were widespread. Only 2 PD sufferers had commenced western type treatment through outsourcing drugs from other parts of the country and outside of Tanzania.

Conclusions

This study highlights the urgent need for PD awareness and treatment interventions in such settings. Such interventions need to address the concerns and needs of sufferers, their carers and the wider community, including the health care system.

Three year follow up of levodopa plus carbidopa treatment in a prevalent cohort of patients with Parkinson's disease in Hai, Tanzania

It was previously thought that the prevalence of Parkinson's disease (PD) in developing countries, and in particular sub-Saharan Africa (SSA), was lower than the rest of the world. The Hai PD prevalence project [1] diagnosed 32 patients (the majority previously undiagnosed and untreated) with PD from a population of 161,000, giving age standardised prevalence rates of 64 (men) and 20 (women)/100,000, respectively. Subsequently, drug treatment has been commenced for all surviving patients with annual follow up. The aim of the study was to document response to treatment, development of side effects, progression of disease and feasibility and sustainability of supplying medication to patients in rural Tanzania. Eleven patients died before the start of medication, and a further four during follow up. One patient moved away from the study area. At the end of 3 years of treatment, 16 patients were surviving. Only one stopped medication due to side effects (dyskinesia). At 3 years, 9/16 experienced wearing off and a further three had dyskinesias. Non motor symptoms were a problem at initial assessment [2] and continued to be a problem for many of the patients. We have shown that it is possible to find, treat and follow up patients with PD in a rural sub-Saharan African setting. Availability of affordable medication locally is a major issue. Acknowledging that movement disorders and neurological diseases in general are an issue in this setting is important to drive education and training, and for allocation of funding from health care providers in SSA.