Thomas Steeves

The prevalence of Parkinson's disease: A systematic review and meta‐analysis

Parkinsons 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.

The incidence and prevalence of Huntington's disease: A systematic review and meta-analysis†‡§

Huntingtons 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.

Prevalence of Tic Disorders: A Systematic Review and Meta-Analysis

This study evaluated the prevalence of tic disorders. MEDLINE and EMBASE databases were searched, using terms specific to Tourette syndrome and tic disorders, for studies of incidence, prevalence, and epidemiology. Thirty-five studies reporting data from 1985-2011 on the incidence or prevalence of tic disorders in a defined population were included. One reported incidence, and 34 reported prevalence. Meta-analysis of 13 studies of children yielded a prevalence of Tourette syndrome at 0.77% (95% confidence interval, 0.39-1.51%). Prevalence is higher in boys: 1.06% of boys were affected (95% confidence interval, 0.54-2.09%) vs 0.25% of girls (95% confidence interval, 0.05-1.20%). Transient tic disorder comprised the most common tic disorder in children, affecting 2.99% (95% confidence interval, 1.60-5.61%). Meta-analysis of two studies assessing adults for Tourette syndrome revealed a prevalence of 0.05% (95% confidence interval, 0.03-0.08%). The prevalence of tic disorders was higher in all studies performed in special education populations. Tic disorders are more common in children than adults, in boys than girls, and in special education populations. Parents, educators, healthcare professionals, and administrators should be aware of the frequency with which tic disorders occur, and ensure proper access to appropriate care.

The prevalence of primary dystonia: a systematic review and meta-analysis.

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.

Phenotype in parkinsonian and nonparkinsonian LRRK2 G2019S mutation carriers

Objectives: Using a family study design, we describe the motor and nonmotor phenotype in probands with LRRK2 G2019S mutations and family members and compare these individuals to patients with idiopathic Parkinson disease (iPD) and unrelated controls. Methods: Probands with G2019S mutations and their first-degree relatives, subjects with iPD, and unrelated control subjects were identified from 4 movement disorders centers. All underwent neurologic examinations and tests of olfaction, color vision, anxiety, and depression inventories. Results: Tremor was more often a presenting feature among 25 individuals with LRRK2-associated PD than among 84 individuals with iPD. Subjects with LRRK2-PD had better olfactory identification compared with subjects with iPD, higher Beck Depression Inventory scores, and higher error scores on Farnsworth-Munsell 100-Hue test of color discrimination. Postural or action tremor was more common among 29 nonmanifesting mutation carriers compared with 53 noncarriers within the families. Nonparkinsonian family members had higher Unified Parkinsons Disease Rating Scale motor scores, more constipation, and worse color discrimination than controls, regardless of mutation status. Conclusions: Although tremor is a more common presenting feature of LRRK2-PD than iPD and some nonmotor features differed in degree, the phenotype is largely overlapping. Postural or action tremor may represent an early sign. Longitudinal evaluation of a large sample of nonmanifesting carriers will be required to describe any premotor phenotype that may allow early diagnosis.

The Prevalence and Incidence of Dementia with Lewy Bodies: a Systematic Review.

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.

Evaluation of neurological patient registries

in the number of national as well as international registries for a variety of neurological conditions, with corresponding increase in the amount of publications arising from these efforts [ref]. The registries were established for determining the natural history of a specific disease, the effectiveness of new treatments, the quality of care and/or other patient-related outcomes. The purpose of this chapter is to provide an approach to registry evaluation and quality assessment. In preparation of this chapter, we reviewed current literature and consensus guidelines on registry evaluations. We also consulted with medical experts and registry/database specialists as part of a national registry meeting to provide feedback and consensus on criteria to be used for evaluation of disease registries in Canada.

Patient recruitment by neurological registries.

BACKGROUND Clinical registries capture patient information contingent upon successful recruitment and retention of patients who will consent to participation. To accomplish this requires the elements that affect patient recruitment. For example, failure to adequately engage physicians or other healthcare professionals can have as much impact on recruitment success as failure to adequately identify the patients relevant to the purposes of the registry. A strategy for recruitment that is not properly targeted to relevant patients will fail to provide desired information.