Wednesday, 30 July 2014
Anxiety may be an early non-motor feature but it is a vitally important symptom to address in the clinic as well...
Expert Rev Neurother. 2014 Aug;14(8):937-46. doi: 10.1586/14737175.2014.936388.
Coakeley S, Martens KE, Almeida QJ.
Parkinson's disease (PD) is typically known for its cardinal motor symptoms, but a growing body of literature is recognizing a multitude of important nonmotor symptoms as well. Anxiety is one of the most common nonmotor symptoms of PD; unfortunately, neither the management of anxiety nor its influence on motor symptoms is well understood. While recent literature indicates a correlation between motor symptoms and anxiety in PD, it remains uncertain whether one symptom acts as the underlying cause of the other. This review considers the cyclic interaction between anxiety and motor symptoms in PD, each exacerbating the other when they coexist. It may be critically important to disentangle if one symptom serves as an underlying cause of the other, since this might dictate appropriate treatment. Neuroanatomical substrates as well as the treatments for both motor symptoms and anxiety are discussed in detail to consider the evidence-base for the management of PD.
Tuesday, 29 July 2014
Large-scale meta-analysis of genome-wide association data identifies six new risk loci for Parkinson's disease
Exciting new analysis of GWAS data showing more about the heritable component of risk of PD...
Mike A Nalls, Nathan Pankratz, Christina M Lill, Chuong B Do, Dena G Hernandez, Mohamad Saad, Anita L DeStefano, Eleanna Kara, Jose Bras, Manu Sharma, Claudia Schulte, Margaux F Keller, Sampath Arepalli, Christopher Letson, Connor Edsall, Hreinn Stefansson, Xinmin Liu, Hannah Pliner, Joseph H Lee, Rong Cheng, International Parkinson's Disease Genomics Consortium (IPDGC), Parkinson's Study Group (PSG) Parkinson's Research: The Organized GENetics Initiative (PROGENI), 23andMe, GenePD, NeuroGenetics Research Consortium (NGRC) et al.
Nature Genetics (2014) doi:10.1038/ng.3043
We conducted a meta-analysis of Parkinson's disease genome-wide association studies using a common set of 7,893,274 variants across 13,708 cases and 95,282 controls. Twenty-six loci were identified as having genome-wide significant association; these and 6 additional previously reported loci were then tested in an independent set of 5,353 cases and 5,551 controls. Of the 32 tested SNPs, 24 replicated, including 6 newly identified loci. Conditional analyses within loci showed that four loci, including GBA, GAK-DGKQ, SNCA and the HLA region, contain a secondary independent risk variant. In total, we identified and replicated 28 independent risk variants for Parkinson's disease across 24 loci. Although the effect of each individual locus was small, risk profile analysis showed substantial cumulative risk in a comparison of the highest and lowest quintiles of genetic risk (odds ratio (OR) = 3.31, 95% confidence interval (CI) = 2.55–4.30; P = 2 × 10−16). We also show six risk loci associated with proximal gene expression or DNA methylation.
Although manual measurement and digital analysis were comparable, digital analysis could help this technique be of more use in multi-centre studies, which are currently limited due to operator and machine dependency...
AJNR Am J Neuroradiol. 2014 Jul 24. [Epub ahead of print]
Skoloudík D, Jelínková M, Blahuta J, Cermák P, Soukup T, Bártová P, Langová K, Herzig R.
BACKGROUND AND PURPOSE:
Increased echogenicity of the substantia nigra is a typical transcranial sonography finding in Parkinson disease. Experimental software for digital analysis of the echogenic substantia nigra area has been developed. The aim of this study was to compare the evaluation of substantia nigra echogenicity by using digital analysis with a manual measurement in patients with Parkinson disease and healthy volunteers.
MATERIALS AND METHODS:
One hundred thirteen healthy volunteers were enrolled in the derivation cohort, and 50 healthy volunteers and 30 patients with Parkinson disease, in the validation cohort. The substantia nigra was imaged from the right and left temporal bone window by using transcranial sonography. All subjects were examined twice by using different sonographic machines by an experienced sonographer. DICOM images of the substantia nigra were encoded; then, digital analysis and manual measurement of the substantia nigra were performed. The 90th percentile of the derivation cohort values was used as a cut-point for the evaluation of the hyperechogenic substantia nigra in the validation cohort. The Spearman coefficient was used for assessment of the correlation between both measurements. The Cohen κ coefficient was used for the assessment of the correlation between both measurements and Parkinson disease diagnosis.
The Spearman coefficient between measurements by using different machines was 0.686 for digital analysis and 0.721 for manual measurement (P < .0001). Hyperechogenic substantia nigra was detected in the same 26 (86.7%) patients with Parkinson disease by using both measurements. Cohen κ coefficients for digital analysis and manual measurement were 0.787 and 0.762, respectively (P < .0001).
The present study showed comparable results when measuring the substantia nigra features conventionally and by using the developed software.
Friday, 25 July 2014
Tai Chi for Improvement of Motor Function, Balance and Gait in Parkinson's Disease: A Systematic Review and Meta-Analysis
PLoS One. 2014 Jul 21;9(7):e102942. doi: 10.1371/journal.pone.0102942. eCollection 2014.
Yang Y, Li XY, Gong L, Zhu YL, Hao YL.
Recently, several studies assessed the effectiveness of Tai Chi for Parkinson's disease (PD), but the role of Tai Chi in the management of PD remained controversial. Therefore, the purpose of this systematic review is to evaluate the evidence on the efficacy of Tai Chi for PD.
Six English and Chinese electronic databases, up to April 2014, were searched to identify relevant studies. The risk of bias in eligible studies was assessed by Cochrane Collaboration's tools. The primary outcomes were motor function, balance and gait in individuals with PD. Standardized mean difference (SMD) and 95% confidence intervals (CI) of random-effect model were calculated. And heterogeneity was assessed based on the I2statistic.
7 randomized controlled trials and 1 non-randomized controlled trial were eligible. The aggregated results suggested that Tai Chi showed beneficial effects in improving motor function (SMD, -0.57; 95% CI -1.11 to -0.04; p = 0.03), balance (SMD, 1.22; 95% CI 0.80 to 1.65; p<0.00001) and functional mobility (SMD, 1.06; 95% CI 0.68 to 1.44; p<0.00001) in patients with PD, but not in improving gait velocity (SMD, -0.02; 95% CI -0.58 to 0.54; p = 0.94), step length (SMD, -0.00; 95% CI -0.57 to 0.56; p = 0.99), or gait endurance (SMD, 0.53; 95% CI -0.07 to 1.12; p = 0.08). Comparing with other active therapies, however, Tai Chi only showed better effects in improving balance (SMD, 0.74; 95% CI 0.38 to 1.10; p<0.0001).
Tai Chi should be a valid complementary and alternative therapy for PD, especially in improving motor function and balance. However, more studies with long follow-up are warrant to confirm the current finding of Tai Chi for PD.
Thursday, 24 July 2014
Natural history of falls in a population-based cohort of patients with Parkinson's disease: An 8-year prospective study
Parkinsonism Relat Disord. 2014 Jul 9. pii: S1353-8020(14)00243-0. doi: 10.1016/j.parkreldis.2014.06.023. [Epub ahead of print]
Hiorth YH, Larsen JP, Lode K, Pedersen KF.
Prospective long-term studies of falls in Parkinson's disease (PD) are scarce.
To examine the development of falls over 8 years in a population-based cohort of ambulatory patients with PD, and to investigate predictors of future falls in non-fallers at baseline.
All patients were examined at baseline and after 4 and 8 years, including the UPDRS, MMSE, Montgomery and Aaberg Depression Rating Scale, Functional Comorbidity Index, and a clinical dementia interview. Logistic regression models were applied to investigate baseline risk factors for future falls. A total of 211 patients were included at baseline, whereas 121 and 64 were re-examined at 4 and 8 years, respectively.
The prevalence of falls increased from 41% (87 of 211) at baseline to 72% (46 of 64) after 8 years of prospective follow-up (disease duration 16.2 ± 4.8 years). Forty-seven non-falling patients at baseline completed all study visits, of these 68% (n = 32) changed fall status during follow-up. Predictive variables for current falling after 4 years were rare or occasional freezing of gait (OR 6.6, 95% CI 1.2-36.9), higher levodopa equivalent doses and more severe speech and axial impairment (both OR 1.3, 95% CI 1.0-1.7) in non-fallers at baseline. Higher baseline age was the only risk factor for current falling after 8 years.
Nearly ¾ of the PD cohort reported falling after 8 years of follow-up. Disease-specific gait and axial impairments were the major risk factors for future falls in non-fallers at baseline. This has implications for patient education and management.
Wednesday, 23 July 2014
Biomed Res Int. 2014;2014:308654. Epub 2014 Jun 24.
Chao Y, Wong SC, Tan EK.
Parkinson's disease (PD) is a chronic neurodegenerative disease underpinned by both genetic and environmental etiologic factors. Recent findings suggest that inflammation may be a pathogenic factor in the onset and progression of both familial and sporadic PD. Understanding the precise role of inflammatory factors in PD will likely lead to understanding of how the disease arises. In vivo evidence for inflammation in PD includes dysregulated molecular mediators such as cytokines, complement system and its receptors, resident microglial activation, peripheral immune cells invasion, and altered composition and phenotype of peripheral immune cells. The growing awareness of these factors has prompted novel approaches to modulate the immune system, although it remains whether these approaches can be used in humans. Influences of ageing and differential exposure to environmental agents suggest potential host-pathogen specific pathophysiologic factors. There is a clear need for research to further unravel the pathophysiologic role of immunity in PD, with the potential of developing new therapeutic targets for this debilitating condition.
Tuesday, 22 July 2014
The modern pre-levodopa era of Parkinson's disease: insights into motor complications from sub-Saharan Africa
Nice to see some evidence for what is suspected in the clinic...
Brain. 2014 Jul 17. pii: awu195. [Epub ahead of print]
Cilia R, Akpalu A, Sarfo FS, Cham M, Amboni M, Cereda E, Fabbri M, Adjei P, Akassi J, Bonetti A, Pezzoli G.
During the past decade, a number of large drug trials suggested that the initiation of levodopa therapy should be delayed to reduce the risk of motor complications in patients with Parkinson's disease. However, the relative contribution of the cumulative exposure to levodopa and of disease progression to the pathophysiology of motor fluctuations and dyskinesias is still poorly understood. In this 4-year multicentre study, we investigated a large cohort of patients with Parkinson's disease in a sub-Saharan African country (Ghana), where access to medication is limited and the initiation of levodopa therapy often occurs many years after onset. The primary objective was to investigate whether the occurrence of motor complications is primarily related to the duration of levodopa therapy or to disease-related factors. Study design included a cross-sectional case-control analysis of data collected between December 2008 and November 2012, and a prospective study of patients followed-up for at least 6 months after the initiation of levodopa therapy. Ninety-one patients fulfilled criteria for clinical diagnosis of idiopathic Parkinson's disease (58 males, mean age at onset 60.6 ± 11.3 years). Demographic data were compared to those of 2282 consecutive Italian patients recruited during the same period, whereas nested matched subgroups were used to compare clinical variables. Demographic features, frequency and severity of motor and non-motor symptoms were comparable between the two populations, with the only exception of more frequent tremor-dominant presentation in Ghana. At baseline, the proportion of Ghanaian patients with motor fluctuations and dyskinesias was 56% and 14%, respectively. Although levodopa therapy was introduced later in Ghana (mean disease duration 4.2 ± 2.8 versus 2.4 ± 2.1 years, P < 0.001), disease duration at the occurrence of motor fluctuations and dyskinesias was similar in the two populations. In multivariate analysis, disease duration and levodopa daily dose (mg/kg of body weight) were associated with motor complications, while the disease duration at the initiation of levodopa was not. Prospective follow-up for a mean of 2.6 ± 1.3 years of a subgroup of 21 patients who were drug-naïve at baseline [median disease duration 4.5 (interquartile range, 2.3-5) years] revealed that the median time to development of motor fluctuations and dyskinesias after initiation of levodopa therapy was 6 months. We conclude that motor fluctuations and dyskinesias are not associated with the duration of levodopa therapy, but rather with longer disease duration and higher levodopa daily dose. Hence, the practice to withhold levodopa therapy with the objective of delaying the occurrence of motor complications is not justified.
Thursday, 17 July 2014
Predictors of dementia in Parkinson's disease; findings from a 5-year prospective study using the SCOPA-COG
Parkinsonism Relat Disord. 2014 Jun 26. pii: S1353-8020(14)00226-0. doi: 10.1016/j.parkreldis.2014.06.006. [Epub ahead of print]
Zhu K, van Hilten JJ, Marinus J.
Aim of this study was to identify risk factors for the development of dementia in patients with Parkinson's disease (PD).
A broad range of motor and non-motor features was assessed at baseline and the following five years in 406 PD patients. Cross-sectional analyses of baseline data and longitudinal analyses of follow-up data were performed to identify risk factors for dementia.
Thirty-two percent of patients (n = 129) had dementia at baseline, while 26% of patients (n = 68) without dementia at baseline developed dementia during follow-up. Univariate survival analysis showed that higher age, fewer years of education, longer disease duration, higher age-at-onset, higher levodopa dose, higher Hoehn & Yahr stage, presence of dyskinesias, excessive daytime sleepiness (EDS), presence of hallucinations, and more severe autonomic and depressive symptoms were associated with an increased risk of dementia. Higher baseline Postural-Instability-and-Gait-Difficulty scores were also associated with an increased risk of dementia, whereas no effect of tremor severity was found. These findings largely corresponded with the variables that were associated with the presence of dementia at baseline. In a stepwise regression model, higher age at baseline, fewer years of education, higher daily levodopa dose and excessive daytime sleepiness (EDS) emerged as independent risk factors of future dementia.
In this large prospective cohort study, we identified a combination of potentially interacting risk factors for dementia in PD that are associated with higher age and more advanced disease.
Wednesday, 16 July 2014
The association between chronic obstructive pulmonary disease and Parkinson's disease: a nationwide population-based retrospective cohort study
This surprises me given the strong negative associations with PD and smoking. In fact I can't remember ever having seen someone with PD and COPD in clinic...
QJM. 2014 Jul 14. pii: hcu136. [Epub ahead of print]
Li CH, Chen WC, Liao WC, Tu CY, Lin CL, Sung FC, Chen CH, Hsu WH.
Previous research has shown that patients with chronic obstructive pulmonary disease (COPD) tend to have a higher risk for cognitive impairment and dementia, a neurodegenerative disorder. The goal of this study was to examine what relationship, if any, exists between COPD and Parkinson's disease (PD), which is also a neurodegenerative disorder.
Our study analyzed medical data from the population of Taiwan from 1998 to 2008, with a follow-up period extending to the end of 2010. We identified patients with COPD by the Taiwan National Health Insurance Research Database (NHIRD). We selected a comparison cohort from the general population that was random frequency-matched by age (in 5-year increments), sex and index year, and further analyzed the risk of PD using Cox's regression model, including sex, age and comorbidities.
The study enrolled 20 728 COPD patients (71.1% male, mean age = 68.2 years) and 41 147 controls. The risk of developing PD was 1.37 times greater in patients with COPD compared with patients without COPD after adjusting for age, sex and comorbidities. A significantly increased risk of PD was also found in patients with COPD who had any comorbidity other than diabetes.
This nationwide retrospective cohort study demonstrates that PD risk is significantly increased in patients with COPD compared with those of the general population.
Tuesday, 15 July 2014
Ther Adv Neurol Disord. 2014 Jul;7(4):206-20. doi: 10.1177/1756285613511507.
Pyatigorskaya N, Gallea C, Garcia-Lorenzo D, Vidailhet M, Lehericy S.
To date, the most frequently used Parkinson's disease (PD) biomarkers are the brain imaging measures of dopaminergic dysfunction using positron emission tomography and single photon emission computed tomography. However, major advances have occurred in the development of magnetic resonance imaging (MRI) biomarkers for PD in the past decade. Although conventional structural imaging remains normal in PD, advanced techniques have shown changes in the substantia nigra and the cortex. The most well-developed MRI markers in PD include diffusion imaging and iron load using T2/T2* relaxometry techniques. Other quantitative biomarkers such as susceptibility-weighted imaging for iron load, magnetization transfer and ultra-high-field MRI have shown great potential. More sophisticated techniques such as tractography and resting state functional connectivity give access to anatomical and functional connectivity changes in the brain, respectively. Brain perfusion can be assessed using non-contrast-agent techniques such as arterial spin labelling and spectroscopy gives access to metabolites concentrations. However, to date these techniques are not yet fully validated and standardized quantitative metrics for PD are still lacking. This review presents an overview of new structural, perfusion, metabolic and anatomo-functional connectivity biomarkers, their use in PD and their potential applications to improve the clinical diagnosis of Parkinsonian syndromes and the quality of clinical trials.
Monday, 14 July 2014
Mov Disord. 2014 Jul 3. doi: 10.1002/mds.25952. [Epub ahead of print]
Dijkstra AA, Voorn P, Berendse HW, Groenewegen HJ; Netherlands Brain Bank, Rozemuller AJ, van de Berg WD.
To gain a better understanding of the significance of α-synuclein pathological conditions during disease progression in Parkinson's disease, we investigated whether 1) nigral neuronal loss in incidental Lewy body disease and Parkinson's disease donors is associated with the local burden α-synuclein pathological conditions during progression of pathological conditions; 2) the burden and distribution of α-synuclein pathological conditions are related to clinical measures of disease progression. Post-mortem tissue and medical records of 24 Parkinson's disease patients, 20 incidental Lewy body disease donors, and 12 age-matched controls were obtained from the Netherlands Brain Bank for morphometric analysis. We observed a 20% decrease in nigral neuronal cell density in incidental Lewy body disease compared with controls. Nigral neuronal loss (12%) was already observed before the appearance α-synuclein aggregates. The progression from Braak α-synuclein stage 3 to 4 was associated with a significant decline in neuronal cell density (46%). Nigral neuronal loss increased with later Braak α-synuclein stages but did not vary across consecutive Braak α-synuclein stages. We observed a negative correlation between neuronal density and local α-synuclein burden in the substantia nigra of Parkinson's disease patients (ρ = -0.54), but no relationship with Hoehn & Yahr stage or disease duration. In conclusion, our findings cast doubt on the pathogenic role of α-synuclein aggregates in elderly, but do suggest that the severity of neurodegeneration and local burden of α-synuclein pathological conditions are closely coupled during disease progression in Parkinson's disease.
Sunday, 13 July 2014
Another genetic risk factor for PD...?
Brain. 2014 Jul 2. pii: awu179. [Epub ahead of print]
Mencacci NE, Isaias IU, Reich MM, Ganos C, Plagnol V, Polke JM, Bras J, Hersheson J, Stamelou M, Pittman AM, Noyce AJ, Mok KY, Opladen T, Kunstmann E, Hodecker S, Münchau A, Volkmann J, Samnick S, Sidle K, Nanji T, Sweeney MG, Houlden H, Batla A, Zecchinelli AL, Pezzoli G, Marotta G, Lees A, Alegria P, Krack P, Cormier-Dequaire F, Lesage S, Brice A, Heutink P, Gasser T, Lubbe SJ, Morris HR, Taba P, Koks S, Majounie E, Raphael Gibbs J, Singleton A, Hardy J, Klebe S, Bhatia KP, Wood NW; on behalf of the International Parkinson’s Disease Genomics Consortium and UCL-exomes consortium.
GTP cyclohydrolase 1, encoded by the GCH1 gene, is an essential enzyme for dopamine production in nigrostriatal cells. Loss-of-function mutations in GCH1 result in severe reduction of dopamine synthesis in nigrostriatal cells and are the most common cause of DOPA-responsive dystonia, a rare disease that classically presents in childhood with generalized dystonia and a dramatic long-lasting response to levodopa. We describe clinical, genetic and nigrostriatal dopaminergic imaging ([123I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) tropane single photon computed tomography) findings of four unrelated pedigrees with DOPA-responsive dystonia in which pathogenic GCH1 variants were identified in family members with adult-onset parkinsonism. Dopamine transporter imaging was abnormal in all parkinsonian patients, indicating Parkinson's disease-like nigrostriatal dopaminergic denervation. We subsequently explored the possibility that pathogenic GCH1 variants could contribute to the risk of developing Parkinson's disease, even in the absence of a family history for DOPA-responsive dystonia. The frequency of GCH1 variants was evaluated in whole-exome sequencing data of 1318 cases with Parkinson's disease and 5935 control subjects. Combining cases and controls, we identified a total of 11 different heterozygous GCH1 variants, all at low frequency. This list includes four pathogenic variants previously associated with DOPA-responsive dystonia (Q110X, V204I, K224R and M230I) and seven of undetermined clinical relevance (Q110E, T112A, A120S, D134G, I154V, R198Q and G217V). The frequency of GCH1 variants was significantly higher (Fisher's exact test P-value 0.0001) in cases (10/1318 = 0.75%) than in controls (6/5935 = 0.1%; odds ratio 7.5; 95% confidence interval 2.4-25.3). Our results show that rare GCH1 variants are associated with an increased risk for Parkinson's disease. These findings expand the clinical and biological relevance of GTP cycloydrolase 1 deficiency, suggesting that it not only leads to biochemical striatal dopamine depletion and DOPA-responsive dystonia, but also predisposes to nigrostriatal cell loss. Further insight into GCH1-associated pathogenetic mechanisms will shed light on the role of dopamine metabolism in nigral degeneration and Parkinson's disease.
Saturday, 12 July 2014
Important for groups like us who are looking combination of early features...
Mov Disord. 2014 Jul 1. doi: 10.1002/mds.25950. [Epub ahead of print]
Chen H, Huang X, Guo X, Peddada S.
Some nonmotor symptoms may precede the clinical diagnosis of Parkinson's disease (PD) by years.
We examined the individual and joint prevalence of depression, daytime sleepiness, and infrequent bowel movement among 10,477 participants of the US National Health and Nutrition Examination Surveys 2005-2008.
For all symptoms, the prevalence was higher in women than in men. Importantly, few participants had two or more symptoms: 1.3% at ages 20 to 29, 1.0% at 30 to 39, 1.2% at 40 to 49, 3.5% at 50 to 59, 1.7% at 60 to 69, 1.1% at 70 to 79, and 1.2% at ages 80 years or older in men; the corresponding prevalence in women was 3.1%, 5.2%, 5.7%, 4.1%, 3.1%, 2.3%, and 1.2%, respectively. In both men and women, depression was correlated with infrequent bowel movement and daytime sleepiness, but the latter two were mutually independent.
The presence of multiple nonmotor symptoms was uncommon in the general population and the prevalence was higher in women than in men.
Thursday, 10 July 2014
Comparison between visual assessment of dopaminergic degeneration pattern and semi-quantitative ratio calculations in patients with Parkinson's disease and Atypical Parkinsonian syndromes using DaTSCAN® SPECT.
Better characterisation of imaging differences between PD and atypical PD will really help us in the clinic...
Ann Nucl Med. 2014 Jul 6. [Epub ahead of print]
Davidsson A, Georgiopoulos C, Dizdar N, Granerus G, Zachrisson H.
To verify if 123I-FP-CIT, DaTSCAN® can differentiate early stages of Parkinson's disease (PD) as well as patients with Atypical Parkinsonian syndromes (APS) from manifest Parkinson's disease.
128 consecutive patients were investigated with 123I-FP-CIT SPECT during a 4-year period. All patients were diagnosed according to the established consensus criteria for diagnosis of PD (n = 53) and APS (n = 19). Remaining patients were grouped early PD (before onset of L-DOPA medication), (n = 20), vascular PD (n = 6), and non-PD syndromes (n = 30) and SWEDD (n = 1). SPECT images were analyzed visually according to a predefined ranking scale of dopaminergic nerve cell degeneration, distinguishing a posterior-anterior degeneration pattern (egg shape) from a more global and severe degeneration pattern (burst striatum). Striatum uptake ratios were quantitatively analyzed with the 3D software, EXINI.
In the group of APS patients, the burst striatum pattern was most frequent and found in 61 % (11/18 patients). In PD patients, the egg shape pattern was dominating, especially in early PD where it was present in 95 % (19/20 patients). The positive predictive value for the egg shape pattern to diagnose PD was 92 % in this material (APS and all PD patients) and the specificity 90 % for the burst striatum pattern to exclude APS. The uptake ratios were reduced in both PD and APS patients and closely related to the image ranking.
In this study, we found that in more than half of the patients it was possible to differentiate between PD and APS by visual interpretation only. Similar results were obtained using semi-quantitative uptake ratios. Combining visual assessment with uptake ratios did not add to the discriminating power of DaTSCAN® SPECT in this material.
Saturday, 5 July 2014
Neurology. 2014 Jun 27. pii: 10.1212/WNL.0000000000000641. [Epub ahead of print]
Adler CH, Beach TG, Hentz JG, Shill HA, Caviness JN, Driver-Dunckley E, Sabbagh MN, Sue LI, Jacobson SA, Belden CM, Dugger BN.
Determine diagnostic accuracy of a clinical diagnosis of Parkinson disease (PD) using neuropathologic diagnosis as the gold standard.
Data from the Arizona Study of Aging and Neurodegenerative Disorders were used to determine the predictive value of a clinical PD diagnosis, using 2 clinical diagnostic confidence levels, PossPD (never treated or not clearly responsive) and ProbPD (responsive to medications). Neuropathologic diagnosis was the gold standard.
Based on first visit, 9 of 34 (26%) PossPD cases had neuropathologically confirmed PD while 80 of 97 (82%) ProbPD cases had confirmed PD. PD was confirmed in 8 of 15 (53%) ProbPD cases with <5 years of disease duration and 72 of 82 (88%) with ≥5 years of disease duration. Using final diagnosis at time of death, 91 of 107 (85%) ProbPD cases had confirmed PD. Clinical variables that improved diagnostic accuracy were medication response, motor fluctuations, dyskinesias, and hyposmia.
Using neuropathologic findings of PD as the gold standard, this study establishes the novel findings of only 26% accuracy for a clinical diagnosis of PD in untreated or not clearly responsive subjects, 53% accuracy in early PD responsive to medication (<5 years' duration), and >85% diagnostic accuracy of longer duration, medication-responsive PD. Caution is needed when interpreting clinical studies of PD, especially studies of early disease that do not have autopsy confirmation. The need for a tissue or other diagnostic biomarker is reinforced.
This study provides Class II evidence that a clinical diagnosis of PD identifies patients who will have pathologically confirmed PD with a sensitivity of 88% and specificity of 68%.
Friday, 4 July 2014
Mov Disord. 2014 Jun 28. doi: 10.1002/mds.25945. [Epub ahead of print]
Pringsheim T, Jette N, Frolkis A, Steeves TD.
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.
Thursday, 3 July 2014
Curr Opin Neurol. 2014 Aug;27(4):434-441.
Goldman JG, Postuma R.
PURPOSE OF REVIEW:
This review highlights recent advances in premotor and nonmotor features in Parkinson's disease, focusing on these issues in the context of prodromal and early-stage Parkinson's disease.
Although Parkinson's disease patients experience a wide range of nonmotor symptoms throughout the disease course, studies demonstrate that nonmotor features are not solely a late manifestation. Indeed, disturbances of smell, sleep, mood, and gastrointestinal function may herald Parkinson's disease or related synucleinopathies and precede these neurodegenerative conditions by 5 or more years. In addition, other nonmotor symptoms such as cognitive impairment are now recognized in incident or de-novo Parkinson's disease cohorts. Many of these nonmotor features reflect disturbances in nondopaminergic systems and early involvement of peripheral and central nervous systems, including olfactory, enteric, and brainstem neurons as in Braak's proposed pathological staging of Parkinson's disease. Current research focuses on identifying potential biomarkers that may detect persons at risk for Parkinson's disease and permit early intervention with neuroprotective or disease-modifying therapeutics.
Recent studies provide new insights into the frequency, pathophysiology, and importance of nonmotor features in Parkinson's disease as well as the recognition that these nonmotor symptoms occur in premotor, early, and later phases of Parkinson's disease.
Tuesday, 1 July 2014
Inflammation and insulin/IGF-1 resistance as the possible link between obesity and neurodegeneration
J Neuroimmunol. 2014 Jun 12. pii: S0165-5728(14)00175-1. doi: 10.1016/j.jneuroim.2014.06.004. [Epub ahead of print]
Spielman LJ, Little JP, Klegeris A.
Obesity is a growing epidemic that contributes to several brain disorders including Alzheimer's, Parkinson's, and Huntington's diseases. Obesity could promote these diseases through several different mechanisms. Here we review evidence supporting the involvement of two recently recognized factors linking obesity with neurodegeneration: the induction of pro-inflammatory cytokines and onset of insulin and insulin-like growth factor 1 (IGF-1) resistance. Excess peripheral pro-inflammatory mediators, some of which can cross the blood brain barrier, may trigger neuroinflammation, which subsequently exacerbates neurodegeneration. Insulin and IGF-1 resistance leads to weakening of neuroprotective signaling by these molecules and can contribute to onset of neurodegenerative diseases.
This research study compared patients with Parkinson's who carry the commonest gene mutation associated with the disease (called LRRK2),...
What motivates Parkinson's disease patients to enter clinical trials? Valadas A, Coelho M, Mestre T et al. Parkinsonism Relat Disord....
Motor and non-motor correlates of olfactory dysfunction in Parkinson's disease. Berendse HW , Roos DS , Raijmakers P , Doty RL . J...