Search

Advanced high strength steels (AHSS) are used extensively in the automotive industry in the ongoing effort to reduce vehicle weight. Their increased strength allows for the reduction of sheet thickness, and thus a reduction in mass, while offering formability and cost advantages when compared to other metal alloys typically considered for lightweight applications. DP980 steels are AHSS being considered for structural energy absorbing components; however, there is a lack of published information on their high rate behaviour. This paper presents the results of an experimental program that characterized three production DP980 steels from three different manufacturers at strain rates of 0.001, 1, 10, 100 and 1,000 s-1. An electro-mechanical frame was used for the quasi-static tests, the 1, 10, and 100 s-1 tests were carried out using a fast hydraulic apparatus and the 1,000 s-1 experiments were carried out using a tensile split Hopkinson bar. The quasi-static hardening response at strains higher than the uniform elongation of about 7% was obtained by using a shear test, thus avoiding the use of inverse modelling techniques. The results indicate that the DP980 steels are moderately rate sensitive, with one of the materials showing higher sensitivity than the others. One of the materials exhibited a yield point phenomenon that appears to affect the behaviour of the material at 100 and 1,000 s-1, however, the reasons for this behaviour remain an open question. The data was fit to modified Johnson-Cook and Cowper-Symonds model to account for rate sensitivity. The results presented in this paper provide a tool for modelling the dynamic behaviour of DP980 steels.

While the third generation of advanced high-strength steels (3rd Gen AHSS) have increasingly gained attention for automotive lightweighting, it remains unclear to what extent the developed methodologies for the conventional dual-phase (DP) steels are applicable to this new class of steels. The present paper provides a comprehensive study on the constitutive, formability, tribology, and fracture behavior of three commercial 3rd Gen AHSS with an ultimate strength level ranging from 980 to 1180 MPa which are contrasted with two DP steels of the same strength levels and the 590R AHSS. The hardening response to large strain levels was determined experimentally using tensile and shear tests and then evaluated in 3D simulations of tensile tests. In general, the strain rate sensitivity of the two 3rd Gen 1180 AHSS was significantly different as one grade exhibited larger transformation-induced behavior. The in-plane formability of the three 1180 MPa steels was similar but with a stark contrast in the local formability whereas the opposite trend was observed for the 3rd Gen 980 and the DP980 steel. The forming limit curves could be accurately predicted using the experimentally measured hardening behavior and the deterministic modified Bressan-Williams through-thickness shear model or the linearized Modified Maximum Force Criterion. The resistance to sliding of the three 3rd Gen AHSS in the Twist Compression Test revealed a comparable coefficient of friction to the 590R except for the electro-galvanized 3rd Gen 1180 V1. An efficient experimental approach to fracture characterization for AHSS was developed that exploits tool contact and bending to obtain fracture strains on the surface of the specimen by suppressing necking. Miniature conical hole expansion, biaxial punch tests, and the VDA 238-100 bend test were performed to construct stress-state dependent fracture loci for use in forming and crash simulations. It is demonstrated that, the 3rd Gen 1180 V2 can potentially replace the DP980 steel in terms of both the global and local formability.

Objective: To review population-based studies of the prevalence and incidence of epilepsy worldwide and use meta-analytic techniques to explore factors that may explain heterogeneity between estimates., Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards were followed. We searched MEDLINE and EMBASE for articles published on the prevalence or incidence of epilepsy since 1985. Abstract, full-text review, and data abstraction were conducted in duplicate. Meta-analyses and meta-regressions were used to explore the association between prevalence or incidence, age group, sex, country level income, and study quality., Results: A total of 222 studies were included (197 on prevalence, 48 on incidence). The point prevalence of active epilepsy was 6.38 per 1,000 persons (95% confidence interval [95% CI] 5.57-7.30), while the lifetime prevalence was 7.60 per 1,000 persons (95% CI 6.17-9.38). The annual cumulative incidence of epilepsy was 67.77 per 100,000 persons (95% CI 56.69-81.03) while the incidence rate was 61.44 per 100,000 person-years (95% CI 50.75-74.38). The prevalence of epilepsy did not differ by age group, sex, or study quality. The active annual period prevalence, lifetime prevalence, and incidence rate of epilepsy were higher in low to middle income countries. Epilepsies of unknown etiology and those with generalized seizures had the highest prevalence., Conclusions: This study provides a comprehensive synthesis of the prevalence and incidence of epilepsy from published international studies and offers insight into factors that contribute to heterogeneity between estimates. Significant gaps (e.g., lack of incidence studies, stratification by age groups) were identified. Standardized reporting of future epidemiologic studies of epilepsy is needed., (© 2016 American Academy of Neurology.)

Background: Understanding the epidemiology of traumatic brain injury (TBI) is essential to shape public health policy, implement prevention strategies, and justify allocation of resources toward research, education, and rehabilitation in TBI. There is not, to our knowledge, a systematic review of population-based studies addressing the epidemiology of TBI that includes all subtypes. We performed a comprehensive systematic review and meta-analysis of the worldwide incidence of TBI., Methods: A search was conducted on May 23, 2014, in Medline and EMBASE according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Abstracts were screened independently and in duplicate to identify original research. Study quality and ascertainment bias were assessed in duplicate using a previously published tool. Demographic data and incidence estimates from each study were recorded, along with stratification by age, gender, year of data collection, and severity., Results: The search strategy yielded 4944 citations. Two hundred and sixteen articles met criteria for full-text review; 144 were excluded. Hand searching resulted in ten additional articles. Eighty-two studies met all eligibility criteria. The pooled annual incidence proportion for all ages was 295 per 100,000 (95% confidence interval: 274-317). The pooled incidence rate for all ages was 349 (95% confidence interval: 96.2-1266) per 100,000 person-years. Incidence proportion and incidence rate were examined to see if associated with age, sex, country, or severity., Conclusions: We conclude that most TBIs are mild and most TBIs occur in males among the adult population. The incidence of TBI varies widely by ages and between countries. Despite being an important medical, economic, and social problem, the global epidemiology of TBI is still not well-characterized in the current literature. Understanding the incidence of TBI, particularly mild TBI, remains challenging because of nonstandardized reporting among neuroepidemiological studies.

Background: Population-based prevalence and incidence studies are essential for understanding the societal burden of dementia with Lewy bodies (DLB)., Methods: The MEDLINE and EMBASE databases were searched to identify publications addressing the incidence and/or prevalence of DLB. References of included articles and prior systematic reviews were searched for additional studies. Two reviewers screened all abstracts and full-text reviews, abstracted data and performed quality assessments., Results: Twenty-two studies were included. Incidence rates ranged from 0.5 to 1.6 per 1000 person-years. DLB accounted for 3.2-7.1% of all dementia cases in the incidence studies. Point and period prevalence estimates ranged from 0.02 to 63.5 per 1000 persons. Increasing prevalence estimates were reported with increasing age. DLB accounted for from 0.3 to 24.4% of all cases of dementia in the prevalence studies., Conclusions: DLB becomes more common with increasing age and accounts for about 5% of all dementia cases in older populations.

Background: The muscular dystrophies are a heterogeneous group of genetic muscle diseases with variable distribution of weakness and mode of inheritance., Methods: We previously performed a systematic review of worldwide population-based studies on Duchenne and Becker muscular dystrophies; the current study focused on the epidemiology of other muscular dystrophies using Medline and EMBASE databases. Two reviewers independently reviewed all abstracts, full-text articles, and abstracted data from 1985 to 2011. Pooling of prevalence estimates was performed using random-effect models., Results: A total of 1104 abstracts and 167 full-text articles were reviewed. Thirty-one studies met all eligibility criteria and were included in the final analysis. The overall pooled prevalence of combined muscular dystrophies was 16.14 (confidence interval [CI], 11.21-23.23) per 100,000. The prevalence estimates per 100,000 were 8.26 (CI, 4.99-13.68) for myotonic dystrophy, 3.95 (CI, 2.89-5.40) for facioscapulohumeral dystrophy, 1.63 (CI, 0.94-2.81) for limb girdle muscular dystrophy, and 0.99 (CI, 0.62-1.57) for congenital muscular dystrophies., Conclusions: The studies differed widely in their approaches to case ascertainment, and substantial gaps remain in the global estimates of many other types of muscular dystrophies. Additional epidemiological studies using standardized diagnostic criteria as well as multiple sources of case ascertainment will help address the economic impact and health care burden of muscular dystrophies worldwide.

Objective: Cognitive rehabilitation (CR) is a well-researched therapeutic option for a variety of neurocognitive problems. Recently, CR has been proposed as an option for patients who experience cognitive difficulties following epilepsy surgery (ES). However, there is inconsistency in reporting the efficacy of CR in this population. We appraise existing evidence regarding CR approaches in patients undergoing resective ES and review effectiveness of specific CR strategies., Methods: A comprehensive literature search using MEDLINE, Embase, CINAHL, PsycINFO, and EBM Reviews (including the Cochrane database) identified studies in English published before September 2014, without age restriction, related to CR in patients who underwent resective ES. We included studies focused on patients who underwent ES and who received at least one type of cognitive rehabilitation., Results: Of 2,059 citations identified, four fulfilled eligibility criteria (n = 577), and all investigated the effectiveness of specific CR strategies in patients with either left or right temporal lobe resections. CR strategies used included internal compensatory strategies, external memory aids, psychoeducation, verbal and visual memory training, and exercises of attention and executive functions. None were randomized trials, and only one study involved standardized methods or described the procedures in detail. Evidence suggests that CR may contribute to improvements in aspects of verbal memory, with particular benefit of visual imagery techniques; CR aimed at verbal memory functions may be less effective for patients with hemispheric-dominant resections, and figural memory may not be improved by CR. Furthermore, CR may improve functional and life outcomes, but its timing does not appear to influence its effectiveness., Significance: We demonstrate that CR interventions are overwhelmingly under researched or underreported, and there is a need for a systematic evaluation of CR in this patient population. CR should be given greater attention after ES to determine its efficacy and role in the management of these patients., (Wiley Periodicals, Inc. © 2015 International League Against Epilepsy.)

Background and Purpose: An ability to predict early reperfusion with IV tPA in patients with acute ischemic stroke and intracranial clots can help clinicians decide if additional intra-arterial therapy is needed or not. We explored the association between novel clot characteristics on baseline CTA and early reperfusion with IV tPA in patients with acute ischemic stroke by using classification and regression tree analysis., Materials and Methods: Data are from patients with acute ischemic stroke and proximal anterior circulation occlusions from the Calgary CTA data base (2003-2012) and the Keimyung Stroke Registry (2005-2009). Patients receiving IV tPA followed by intra-arterial therapy were included. Clot location, length, residual flow within the clot, ratio of contrast Hounsfield units pre- and postclot, and the M1 segment origin to the proximal clot interface distance were assessed on baseline CTA. Early reperfusion (TICI 2a and above) with IV tPA was assessed on the first angiogram., Results: Two hundred twenty-eight patients (50.4% men; median age, 69 years; median baseline NIHSS score, 17) fulfilled the inclusion criteria. Median symptom onset to IV tPA time was 120 minutes (interquartile range = 70 minutes); median IV tPA to first angiography time was 70.5 minutes (interquartile range = 62 minutes). Patients with residual flow within the clot were 5 times more likely to reperfuse than those without it. Patients with residual flow and a shorter clot length (≤15 mm) were most likely to reperfuse (70.6%). Patients with clots in the M1 MCA without residual flow reperfused more if clots were distal and had a clot interface ratio in Hounsfield units of <2 (36.8%). Patients with proximal M1 clots without residual flow reperfused 8% of the time. Carotid-T/-L occlusions rarely reperfused (1.7%). Interrater reliability for these clot characteristics was good., Conclusions: Our study shows that clot characteristics on CTA help physicians estimate a range of early reperfusion rates with IV tPA., (© 2014 by American Journal of Neuroradiology.)

Objectives: Approximately 50% of Crohn's disease patients undergo an intestinal resection within 10 years of diagnosis. The risk of second surgery in Crohn's disease and the influence of time are not well characterized. We performed a systematic review and meta-analysis to establish the risk of second abdominal surgery in patients with Crohn's disease among patients who had a previous surgery., Methods: We searched Medline, EMBASE, PubMed (March 2014), and conference proceedings for terms related to Crohn's disease and intestinal surgery. We included population-based articles (n=11) and an abstract (n=1) reporting surgical risk for the overall study period and for 5 and 10 years after the first surgery for Crohn's disease. We stratified studies by year (start year before vs. after 1980) to explore the role of time., Results: For all population-based studies, the overall risk of second surgery was 28.7% (95% confidence interval (CI): 22.6-36.6%). The 5-year risk of second surgery was 24.2% (95% CI: 22.3-26.4%). The 10-year risk of second surgery was 35.0% (95% CI: 31.8-38.6%). A significant difference in the 10-year risk of second surgery was observed over time such that studies conducted after 1980 had a lower risk of second surgery (33.2%; 95% CI: 31.2-35.4%) compared with those that started before 1980 (44.6%; 95% CI: 37.7-52.7%)., Conclusions: Approximately one-quarter of Crohn's disease patients who have a first surgery also have a second, and the majority of these surgeries occur within 5 years of the first surgery. The 10-year risk of second surgery is significantly decreasing over time.

The muscular dystrophies are a broad group of hereditary muscle diseases with variable severity. Population-based prevalence estimates have been reported but pooled estimates are not available. We performed a systematic review of worldwide population-based studies reporting muscular dystrophies prevalence and/or incidence using MEDLINE and EMBASE databases. The search strategy included key terms related to muscular dystrophies, incidence, prevalence and epidemiology. Two reviewers independently reviewed all abstracts, full text articles and abstracted data using standardized forms. Pooling of prevalence estimates was performed using random effect models. 1104 abstracts and 167 full text articles were reviewed. Thirty-one studies met all eligibility criteria and were included in the final analysis. The studies differed widely in their approaches to case ascertainment, resulting in significant methodological heterogeneity and varied data quality. The pooled prevalence of DMD and BMD was 4.78 (95% CI 1.94-11.81) and 1.53 (95% CI 0.26-8.94) per 100,000 males respectively. The incidence of DMD ranged from 10.71 to 27.78 per 100,000. This is the first meta-analysis of worldwide prevalence estimates for muscular dystrophies. There is a need for more epidemiological studies addressing global estimates on incidence and prevalence of muscular dystrophies, utilizing standardized diagnostic criteria as well as multiple sources of case ascertainment., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Objective: Satisfaction with epilepsy care (SEC) encompasses care delivery, expectations, attitudes, and disease course. Through a systematic review of the evidence, we explore how and where the SEC of patients is being measured, the level of SEC overall and in specific domains, and its relationship to clinical and demographic variables., Methods: We searched Medline, PsycINFO, CINAHL, Cochrane Register of Controlled Trials, and EMBASE using medical subject headings and keywords related to satisfaction with care and epilepsy in adults and children, in all languages. Two independent reviewers screened abstracts and full-text articles. We examined the clinical context and patient characteristics, type and content of satisfaction scales, and reported outcomes. Abstracted variables were grouped for descriptive purposes and presented as medians and proportions when the data allowed it., Results: Of 25 included studies (6,336 patients), 88% were performed in the United States or the United Kingdom. Nine studies (36%) used validated instruments and 16 studies (64%) used nonvalidated instruments. For SEC domains reported in >1 study, the median proportion (interquartile range) of patients satisfied with epilepsy care was 86% (17%) for overall satisfaction with care, 85% (24%) for interpersonal skills, 78% (3%) for access to care, 67% (32%) for communication, and 65% (15%) for knowledge/technical skills. Communication and clinicians' knowledge was important in all settings. Patients seen in specialized settings and those receiving more and better information had higher SEC ratings. There was no consistent association between SEC and quality of care indicators., Significance: Data on SEC have been reported infrequently. Patients are least satisfied with communication, perceived skills, and knowledge of care providers. Epilepsy-specific SEC tools have neither been validated nor do they contain many of the important domains identified by this review. The relationship between SEC and indicators of quality of care requires further study. Measures aimed at improving education and communication could improve SEC., (Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.)

Background: The majority of people with epilepsy have a good prognosis and their seizures are controlled by a single antiepileptic drug. However, up to 20% of patients from population-based studies and up to 30% from clinical series (not population-based) develop drug-resistant epilepsy, especially those with partial onset seizures. In this review we summarise the current evidence regarding topiramate, an antiepileptic drug first marketed in 1996, when used as an add-on treatment for drug-resistant partial epilepsy. This is an updated version of the original Cochrane review published in Issue 3, 1999., Objectives: To evaluate the efficacy and safety of topiramate when used as an add-on treatment for people with drug-resistant partial epilepsy., Search Methods: We searched the Cochrane Epilepsy Group Specialised Register (June 2013); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 5); MEDLINE (1946 to 2013); SCOPUS (1823 to 2013); ClinicalTrials.gov and ICTRP. We imposed no language restrictions. We also contacted the manufacturers of topiramate and researchers in the field to identify any ongoing or unpublished studies., Selection Criteria: Randomised, placebo-controlled or active drug controlled add-on trials of topiramate, recruiting people with drug-resistant partial epilepsy., Data Collection and Analysis: Two review authors independently selected trials for inclusion and extracted the relevant data. We assessed the following outcomes: (a) 50% or greater reduction in seizure frequency; (b) seizure freedom; (c) treatment withdrawal (any reason); (d) side effects. Primary analyses were intention-to-treat and summary risk ratios (RR) with 95% confidence intervals (95% CI) are presented. We evaluated dose response in regression models. We carried out a 'Risk of bias' assessment for each included study using the Cochrane 'Risk of bias' tool and assessed the overall quality of evidence using the GRADE approach, which we presented in a 'Summary of findings' table., Main Results: Eleven trials were included, representing 1401 randomised participants. Baseline phases ranged from 4 to 12 weeks and double-blind phases from 11 to 19 weeks. The RR for a 50% or greater reduction in seizure frequency compared to placebo was 2.97 (95% CI 2.38 to 3.72). Dose regression analysis shows increasing effect with increasing dose, but found no advantage for doses over 300 or 400 mg per day. The RR for seizure freedom (95% CI) compared to placebo was 3.41 (95% CI 1.37 to 8.51). The RR for treatment withdrawal compared to placebo was 2.44 (95% CI 1.64 to 3.62). The RRs for the following side effects indicate that they are significantly associated with topiramate: ataxia 2.29 (99% CI 1.10 to 4.77); concentration difficulties 7.81 (2.08 to 29.29); dizziness 1.54 (99% CI 1.07 to 2.22); fatigue 2.19 (99% CI 1.42 to 3.40); paraesthesia 3.91 (1.51 to 10.12); somnolence 2.29 (99% CI 1.49 to 3.51); 'thinking abnormally' 5.70 (99% CI 2.26 to 14.38) and weight loss 3.47 (1.55 to 7.79). Evidence of publication bias was found (P-value from the Egger test was P=0.003). We rated all studies included in the review as having either low or unclear risk of bias. Overall, we assessed the evidence as moderate quality due to the evidence of publication bias., Authors' Conclusions: Topiramate has efficacy as an add-on treatment for drug-resistant partial epilepsy in that it is three times more effective compared to a placebo in reducing seizures. However, the trials reviewed were of relatively short duration and provide no evidence for the long-term efficacy of topiramate. In the short term topiramate as an add-on has been shown to be associated with several adverse events. The results of this review cannot be extrapolated to monotherapy or treatment of other epilepsy types and future research should consider examining the effect of dose.

Background & Aims: The inflammatory bowel diseases (IBDs) are chronic diseases that often require surgery. However, the risk of requirement of surgery over time has not been well characterized. We performed a systematic review and meta-analysis to establish the cumulative risk of surgery among patients with IBD and evaluated how this risk has changed over time., Methods: We searched Medline, EMBASE, PubMed, and conference proceedings (2009-2012) on May 8, 2013, for terms related to IBD and intestinal surgery. Two reviewers screened 8338 unique citations to identify 486 for full-text review. The analysis included population-based studies published as articles (n = 26) and abstracts (n = 4) that reported risks of surgery at 1, 5, or 10 years after a diagnosis of Crohn's disease and/or ulcerative colitis. The trend in risk of surgery over time was analyzed by meta-regression using mixed-effect models., Results: Based on all population-based studies, the risk of surgery 1, 5, and 10 years after diagnosis of Crohn's disease was 16.3% (95% confidence interval [CI], 11.4%-23.2%), 33.3% (95% CI, 26.3%-42.1%), and 46.6% (95% CI, 37.7%-57.7%), respectively. The risk of surgery 1, 5, and 10 years after diagnosis of ulcerative colitis was 4.9% (95% CI, 3.8%-6.3%), 11.6% (95% CI, 9.3%-14.4%), and 15.6% (95% CI, 12.5%-19.6%), respectively. The risk of surgery 1, 5, and 10 years after diagnosis of Crohn's disease and 1 and 10 years after diagnosis of ulcerative colitis has decreased significantly over the past 6 decades (P < .05)., Conclusions: Based on systematic review and meta-analysis of population-based studies, the risk of intestinal surgery among patients with IBD has decreased over the past 6 decades., (Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background: Multiple sclerosis (MS) is the most common cause of neurological disability in young adults worldwide and approximately half of those affected are in Europe. The assessment of differential incidence and prevalence across populations can reveal spatial, temporal and demographic patterns which are important for identifying genetic and environmental factors contributing to MS. However, study methodologies vary and the quality of the methods can influence the estimates. This study aimed to systematically review European studies of incidence and prevalence of MS and to provide a quantitative assessment of their methodological quality., Methods: A comprehensive literature search was performed to obtain all original population-based studies of MS incidence and prevalence in European populations conducted and published between January 1985 and January 2011. Only peer-reviewed full-text articles published in English or French were included. All abstracts were screened for eligibility and two trained reviewers abstracted the data and graded the quality of each study using a tool specifically designed for this study., Results: There were 123 studies that met the inclusion criteria. The study estimates were highly heterogeneous, even within regions or countries. Quality was generally higher in the more recent studies, which also tended to use current diagnostic criteria. Prevalence and incidence estimates tended to be higher in the more recent studies and were higher in the Nordic countries and in northern regions of the British Isles. With rare exceptions, prevalence and incidence estimates were higher in women with ratios as high as 3:1. Few studies examined ethnicity. Epidemiological data at the national level was uncommon and there were marked geographical disparities in available data, with large areas of Europe unrepresented and other regions well-represented in the literature. Only 37% of the studies provided standardized estimates., Conclusions: Despite the breadth of the literature on the epidemiology of MS in Europe, inter-study comparisons are hampered by the lack of standardization. Further research should focus on regions not yet studied and the evaluation of ethnic differences in MS prevalence and incidence. National-level studies using current diagnostic criteria, validated case definitions and similar age- and sex-standardization would allow better geographical comparisons.

Introduction: Systematic reviews are an important knowledge synthesis tool for critical care medicine clinicians and researchers. With new literature available each day, reviewers must balance identifying all relevant literature against timely synthesis. We therefore sought to apply capture-mark-recapture, a novel methodology, to estimate the population of articles available for a systematic review of effective patient rounding practices in critical care medicine., Methods: Capture-mark-recapture was applied retrospectively to estimate the population of articles available for a systematic review of 4 bibliographic databases. All research studies (no methodology restrictions) of patient rounding practices in critical care medicine were included. Estimates of article population size were calculated for search of the bibliographic databases, selection of articles for full-text review, and selection of articles for inclusion in the systematic review., Results: Capture-mark-recapture estimated a population of 28839 articles (95% confidence interval [CI], 12393-70990) for search of the bibliographic databases, 169 articles (95% CI, 152-202) for full-text review, and 48 articles (95% CI, 39-131) for inclusion in the systematic review. These estimates suggest that our search identified 15% (4462/28839) of the population of potentially available articles for the search of the bibliographic databases, 79% (133/169) of articles for full-text review, and 79% (38/48) of articles for inclusion in the systematic review., Conclusions: The capture-mark-recapture technique can be applied to systematic reviews in critical care medicine with heterogeneous study methodologies to estimate the population of articles available. Capture-mark-recapture may help clinicians who use systematic reviews to estimate search completeness and researchers who perform systematic reviews to develop more efficient literature search strategies., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Aims: The aim of this study was to provide a comprehensive update on (1) the overall prevalence of cerebral palsy (CP); (2) the prevalence of CP in relation to birthweight; and (3) the prevalence of CP in relation to gestational age., Method: A systematic review and meta-analysis was conducted and reported, based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement. Population-based studies on the prevalence of CP in children born in 1985 or after were selected. Statistical analysis was carried out using computer package R, version 2.14., Results: A total of 49 studies were selected for this review. The pooled overall prevalence of CP was 2.11 per 1000 live births (95% confidence interval [CI] 1.98-2.25). The prevalence of CP stratified by gestational age group showed the highest pooled prevalence to be in children weighing 1000 to 1499g at birth (59.18 per 1000 live births; 95% CI 53.06-66.01), although there was no significant difference on pairwise meta-regression with children weighing less than 1000g. The prevalence of CP expressed by gestational age was highest in children born before 28 weeks' gestation (111.80 per 1000 live births; 95% CI 69.53-179.78; p<0.0327)., Interpretation: The overall prevalence of CP has remained constant in recent years despite increased survival of at-risk preterm infants., (© The Authors. Developmental Medicine & Child Neurology © 2013 Mac Keith Press.)

Background: The incidence and prevalence of multiple sclerosis (MS) varies considerably around the world. No previous study has performed a comprehensive review examining the incidence and prevalence of MS across the Americas. The purpose of this study was to systematically review and assess the quality of studies estimating the incidence and/or prevalence of MS in North, Central and South American regions., Methods: A comprehensive literature search was performed using MEDLINE and EMBASE from January 1985 to January 2011. Search terms included 'multiple sclerosis', 'incidence', 'prevalence' and 'epidemiology'. Only full-text articles published in English or French were included. Study quality was assessed using an assessment tool based on recognized guidelines and designed specifically for this study., Results: A total of 3,925 studies were initially identified, with 31 meeting the inclusion criteria. The majority of studies examined North American regions (n = 25). Heterogeneity was high among all studies, even when stratified by country. Only half of the studies reported standardized rates, making comparisons difficult. Quality scores ranged from 3/8 to 8/8., Conclusion: This review highlights the gaps that still exist in the epidemiological knowledge of MS in the Americas, and the inconsistencies in methodologies and quality among the published studies. There is a need for future studies of MS prevalence and incidence to include uniform case definitions, employ comparable methods of ascertainment, report standardized results, and be performed on a national level. Other factors such as sex distribution, ethnic make-up and population lifestyle habits should also be considered., (Copyright © 2013 S. Karger AG, Basel.)

Dystonia is a hyperkinetic movement disorder characterized by sustained muscle contractions that produce repetitive movements and abnormal postures. Specific information on the prevalence of dystonia has been difficult to establish because the existing epidemiological studies of the condition have adopted different methodologies for case ascertainment, resulting in widely differing reported prevalence. Medline and Embase databases were searched using terms specific to dystonia for studies of incidence, prevalence, and epidemiology. All population-based studies reporting an incidence and/or prevalence of primary dystonia were included. Sixteen original studies were included in our systematic review. Fifteen studies reported the prevalence of dystonia, including 12 service-based and three population-based studies. We performed a meta-analysis on the results of the service-based studies, and were able to combine data on the prevalence of several dystonia subtypes. From these studies, we calculated an overall prevalence of primary dystonia of 16.43 per 100,000 (95% confidence interval [CI]: 12.09-22.32). The prevalence of dystonia reported in the three population-based studies appears higher than that reported in the service-based studies. Only 1 of the 16 studies reported an incidence of cervical dystonia. This corresponded to a corrected incidence estimate of 1.07 per 100,000 person-years (95% CI: 0.86-1.32). Despite numerous studies on the epidemiology of dystonia, attempting to determine an accurate prevalence of the condition for health services planning remains a significant challenge. Given the methodological limitations of the existing studies, our own prevalence estimate of primary dystonia likely underestimates the true prevalence of the condition., (Copyright © 2012 Movement Disorder Society.)

Huntington's disease (HD) is a rare, neurodegenerative disorder characterized by chorea, behavioral manifestations, and dementia. The aim of this study was to estimate the incidence and prevalence of HD through a systematic review of the literature. Medline and Embase databases were searched using terms specific to HD as well as studies of incidence, prevalence, and epidemiology. All studies reporting the incidence and/or prevalence of HD were included. Twenty original research articles were included. Eight studies examined incidence, and 17 studies examined prevalence. Meta-analysis of data from four incidence studies revealed an incidence of 0.38 per 100,000 per year (95% confidence interval [CI]: 0.16, 0.94). Lower incidence was reported in the Asian studies (n = 2), compared to the studies performed in Europe, North America, and Australia (n = 6). The worldwide service-based prevalence of HD, based on a meta-analysis (n = 13 studies), was 2.71 per 100,000 (95% CI: 1.55-4.72). Eleven studies were conducted in Europe, North American, and Australia, with an overall prevalence of 5.70 per 100,000 (95% CI: 4.42-7.35). Three studies were conducted in Asia, with an overall prevalence of 0.40 per 100,000 (95% CI: 0.26-0.61). Metaregression revealed a significantly lower prevalence of HD in Asia, compared to European, North American, and Australian populations. HD is a devastating neurodegenerative disorder with a higher prevalence in Europe, North America, and Australia than in Asia. The difference in prevalence of this genetic disorder can be largely explained by huntingtin gene haplotypes., (Copyright © 2012 Movement Disorder Society.)