Jodie I. Roberts

Recommendations for optimal ICD codes to study neurologic conditions A systematic review

Objective: Administrative health data are frequently used for large population-based studies. However, the validity of these data for identifying neurologic conditions is uncertain. Methods: This article systematically reviews the literature to assess the validity of administrative data for identifying patients with neurologic conditions. Two reviewers independently assessed for eligibility all abstracts and full-text articles identified through a systematic search of Medline and Embase. Study data were abstracted on a standardized abstraction form to identify ICD code–based case definitions and corresponding sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs). Results: Thirty full-text articles met the eligibility criteria. These included 8 studies for Alzheimer disease/dementia (sensitivity: 8–86.5, specificity: 56.3–100, PPV: 60–97.9, NPV: 68.0–98.9), 2 for brain tumor (sensitivity: 54.0–100, specificity: 97.0–99.0, PPV: 91.0–98.0), 4 for epilepsy (sensitivity: 98.8, specificity: 69.6, PPV: 62.0–100, NPV: 89.5–99.1), 4 for motor neuron disease (sensitivity: 78.9–93.0, specificity: 99.0–99.9, PPV: 38.0–90.0, NPV: 99), 2 for multiple sclerosis (sensitivity: 85–92.4, specificity: 55.9–92.6, PPV: 74.5–92.7, NPV: 70.8–91.9), 4 for Parkinson disease/parkinsonism (sensitivity: 18.7–100, specificity: 0–99.9, PPV: 38.6–81.0, NPV: 46.0), 3 for spinal cord injury (sensitivity: 0.9–90.6, specificity: 31.9–100, PPV: 27.3–100), and 3 for traumatic brain injury (sensitivity: 45.9–78.0 specificity: 97.8, PPV: 23.7–98.0, NPV: 99.2). No studies met eligibility criteria for cerebral palsy, dystonia, Huntington disease, hydrocephalus, muscular dystrophy, spina bifida, or Tourette syndrome. Conclusions: To ensure the accurate interpretation of population-based studies with use of administrative health data, the accuracy of case definitions for neurologic conditions needs to be taken into consideration.

Phase locking, the Moran effect and distance decay of synchrony: experimental tests in a model system

Spatially separated populations of many species fluctuate synchronously. Synchrony typically decays with increasing interpopulation distance. Spatial synchrony, and its distance decay, might reflect distance decay of environmental synchrony (the Moran effect), and/or short-distance dispersal. However, short-distance dispersal can synchronize entire metapopulations if within-patch dynamics are cyclic, a phenomenon known as phase locking. We manipulated the presence/absence of short-distance dispersal and spatially decaying environmental synchrony and examined their separate and interactive effects on the synchrony of the protist prey species Tetrahymena pyriformis growing in spatial arrays of patches (laboratory microcosms). The protist predator Euplotes patella consumed Tetrahymena and generated predator-prey cycles. Dispersal increased prey synchrony uniformly over both short and long distances, and did so by entraining the phases of the predator-prey cycles. The Moran effect also increased prey synchrony, but only over short distances where environmental synchrony was strongest, and did so by increasing the synchrony of stochastic fluctuations superimposed on the predator-prey cycle. Our results provide the first experimental demonstration of distance decay of synchrony due to distance decay of the Moran effect. Distance decay of the Moran effect likely explains distance decay of synchrony in many natural systems. Our results also provide an experimental demonstration of long-distance phase locking, and explain why cyclic populations provide many of the most dramatic examples of long-distance spatial synchrony in nature.

The Prevalence and Incidence of Dementia Due to Alzheimer’s Disease: a Systematic Review and Meta-Analysis

BACKGROUND Updated information on the epidemiology of dementia due to Alzheimers disease (AD) is needed to ensure that adequate resources are available to meet current and future healthcare needs. We conducted a systematic review and meta-analysis of the incidence and prevalence of AD. METHODS The MEDLINE and EMBASE databases were searched from 1985 to 2012, as well as the reference lists of selected articles. Included articles had to provide an original population-based estimate for the incidence and/or prevalence of AD. Two individuals independently performed abstract and full-text reviews, data extraction and quality assessments. Random-effects models were employed to generate pooled estimates stratified by age, sex, diagnostic criteria, location (i.e., continent) and time (i.e., when the study was done). RESULTS Of 16,066 abstracts screened, 707 articles were selected for full-text review. A total of 119 studies met the inclusion criteria. In community settings, the overall point prevalence of dementia due to AD among individuals 60+ was 40.2 per 1000 persons (CI95%: 29.1-55.6), and pooled annual period prevalence was 30.4 per 1000 persons (CI95%: 15.6-59.1). In community settings, the overall pooled annual incidence proportion of dementia due to AD among individuals 60+ was 34.1 per 1000 persons (CI95%: 16.4-70.9), and the incidence rate was 15.8 per 1000 person-years (CI95%: 12.9-19.4). Estimates varied significantly with age, diagnostic criteria used and location (i.e., continent). CONCLUSIONS The burden of AD dementia is substantial. Significant gaps in our understanding of its epidemiology were identified, even in a high-income country such as Canada. Future studies should assess the impact of using such newer clinical diagnostic criteria for AD dementia such as those of the National Institute on Aging-Alzheimers Association and/or incorporate validated biomarkers to confirm the presence of Alzheimer pathology to produce more precise estimates of the global burden of AD.

Neurologists' knowledge of and attitudes toward epilepsy surgery A national survey

Objectives: In the current study, we aim to assess potential neurologist-related barriers to epilepsy surgery among Canadian neurologists. Methods: A 29-item, pilot-tested questionnaire was mailed to all neurologists registered to practice in Canada. Survey items included the following: (1) type of medical practice, (2) perceptions of surgical risks and benefits, (3) knowledge of existing practice guidelines, and (4) barriers to surgery for patients with epilepsy. Neurologists who did not complete the questionnaire after the initial mailing were contacted a second time by e-mail, fax, or telephone. After this reminder, the survey was mailed a second time to any remaining nonresponders. Results: In total, 425 of 796 neurologists returned the questionnaire (response rate 53.5%). Respondents included 327 neurologists who followed patients with epilepsy in their practice. More than half (56.6%) of neurologists required patients to be drug-resistant and to have at least one seizure per year before considering surgery, and nearly half (48.6%) failed to correctly define drug-resistant epilepsy. More than 75% of neurologists identified inadequate health care resources as the greatest barrier to surgery for patients with epilepsy. Conclusions: A substantial proportion of Canadian neurologists are unaware of recommended standards of practice for epilepsy surgery. Access also appears to be a significant barrier to epilepsy surgery and surgical evaluation. As a result, we are concerned that patients with epilepsy are receiving inadequate care. A greater emphasis must be placed on knowledge dissemination and ensuring that the infrastructure and personnel are in place to allow patients to have timely access to this evidence-based treatment.

The Prevalence and Incidence of Dementia: a Systematic Review and Meta-analysis.

UNLABELLED Introduction Dementia is a common neurological condition affecting many older individuals that leads to a loss of independence, diminished quality of life, premature mortality, caregiver burden and high levels of healthcare utilization and cost. This is an updated systematic review and meta-analysis of the worldwide prevalence and incidence of dementia. METHODS The MEDLINE and EMBASE databases were searched for relevant studies published between 2000 (1985 for Canadian papers) and July of 2012. Papers selected for full-text review were included in the systematic review if they provided an original population-based estimate for the incidence and/or prevalence of dementia. The reference lists of included articles were also searched for additional studies. Two individuals independently performed abstract and full-text review, data extraction, and quality assessment of the papers. Random-effects models and/or meta-regression were used to generate pooled estimates by age, sex, setting (i.e., community, institution, both), diagnostic criteria utilized, location (i.e., continent) and year of data collection. RESULTS Of 16,066 abstracts screened, 707 articles were selected for full-text review. A total of 160 studies met the inclusion criteria. Among individuals 60 and over residing in the community, the pooled point and annual period prevalence estimates of dementia were 48.62 (CI95%: 41.98-56.32) and 69.07 (CI95%: 52.36-91.11) per 1000 persons, respectively. The respective pooled incidence rate (same age and setting) was 17.18 (CI95%: 13.90-21.23) per 1000 person-years, while the annual incidence proportion was 52.85 (CI95%: 33.08-84.42) per 1,000 persons. Increasing participant age was associated with a higher dementia prevalence and incidence. Annual period prevalence was higher in North America than in South America, Europe and Asia (in order of decreasing period prevalence) and higher in institutional compared to community and combined settings. Sex, diagnostic criteria (except for incidence proportion) and year of data collection were not associated with statistically significant different estimates of prevalence or incidence, though estimates were consistently higher for females than males. CONCLUSIONS Dementia is a common neurological condition in older individuals. Significant gaps in knowledge about its epidemiology were identified, particularly with regard to the incidence of dementia in low- and middle-income countries. Accurate estimates of prevalence and incidence of dementia are needed to plan for the health and social services that will be required to deal with an aging population.

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.

Neurologists’ and neurology residents’ knowledge of issues related to pregnancy for women with epilepsy

We aimed to assess physician knowledge for 2009 guidelines established by the American Academy of Neurology and American Epilepsy Society regarding issues related to pregnancy for women with epilepsy. A questionnaire was developed and distributed to all neurologists and neurology residents practicing in a large Canadian health region serving a population of 1.4 million. Descriptive statistics were obtained and percentage of correct responses was calculated. Forty-five physicians completed the survey (response rate = 83.3%), with a median correct score of 50%. Residents were more likely (93.3%) to state that this information was important to their practice than staff physicians (40.0%). Overall knowledge of outcomes associated with specific AEDs was poor; less than half of the physicians correctly indicated which AEDs were associated with adverse outcomes for the majority of drug-related questions. We recommend multifaceted, interactive implementation strategies for increasing knowledge of guideline contents.

The prevalence of diagnosed tourette syndrome in Canada: A national population-based study

The objective of this study was to examine: (1) the prevalence of diagnosed Tourette syndrome in Canada by sex in youth (aged 12‐17) and adults and (2) socioeconomic factors in this population.

The Prevalence and Incidence of Frontotemporal Dementia: a Systematic Review.

BACKGROUND Population-based prevalence and incidence studies are essential for understanding the burden of frontotemporal dementia (FTD). METHODS The MEDLINE and EMBASE databases were searched to identify population-based publications from 1985 to 2012, addressing the incidence and/or prevalence of FTD. 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-six studies were included. Methodological limitations led to wide ranges in the estimates for prevalence (point prevalence 0.01-4.6 per 1000 persons; period prevalence 0.16-31.04 per 1000 persons) and incidence (0.0-0.3 per 1000 person-years). FTD accounted for an average of 2.7% (range 0-9.1%) of all dementia cases among prevalence studies that included subjects 65 and older compared to 10.2% (range 2.8-15.7%) in studies restricted to those aged less than 65. The cumulative numbers of male (373 [52.5%]) and female (338 [47.5%]) cases from studies reporting this information were nearly equal (p=0.18). The behavioural variant FTD (bvFTD) was almost four times as common as the primary progressive aphasias. CONCLUSIONS Population-based estimates for the epidemiology of FTD varied widely in the included studies. Refinements in the diagnostic process, possibly by the use of validated biomarkers or limiting case ascertainment to specialty services, are needed to obtain more precise estimates of the prevalence and incidence of FTD.

Patient knowledge about issues related to pregnancy in epilepsy: A cross-sectional study

In 2009, new guidelines were established by the American Academy of Neurology regarding pregnancy in women with epilepsy. A questionnaire was developed to assess patient knowledge of current guidelines related to epilepsy and pregnancy. Patients were recruited from a single outpatient clinic in a large Canadian tertiary care center. Patients were eligible to participate if they were female, of reproductive age, had active epilepsy for at least 6 months and were not cognitively impaired. One hundred women completed the survey (response rate 87%) with a median score of 40%. A significant association was found between total score and years of education (p<0.001). Significant associations were not found between total score and epilepsy duration (p=0.37), previously being pregnant (p=0.22), and polytherapy (p=0.31). Patient knowledge of the impact of epilepsy on pregnancy is low. More knowledge translation efforts are required to increase knowledge of issues related to pregnancy for women with epilepsy.