Severe dementia. Prevalence and clinical features in a biracial US population.

The purpose of this investigation was to document the prevalence of severe dementia among different racial groups residing in the same community--Copiah County, Mississippi. Both household and institutionalized populations were included. For either sex, the prevalence ratios of all severe dementia and clinically diagnosed severe senile dementia of the Alzheimer's type were at least as large among blacks as among whites. For either race, the corresponding prevalence ratios were greater in females. For each race and sex, the corresponding prevalence ratios increased with advancing age. Finally, in the population studied, approximately 1% of individuals 40 years old or older had severe dementia. This figure increased to 7% for individuals 80 years old or older.

Prevalence of essential tremor. Results from the Copiah County study.

This investigation determined the prevalence of essential tremor in a US population. The findings were derived from a large-scale morbidity survey conducted in a rural, biracial Mississippi county (Copiah County). Both the household and the institutionalized populations of the county were included. Results were limited to persons 40 years old or older. Prevalence ratios were higher for women than for men and were higher for whites than for blacks. Age-specific prevalence ratios generally increased with age. The overall prevalence ratio was 414.6 per 100,000 inhabitants.

Racial differentials in the prevalence of stroke. Copiah County, Mississippi.

Separate surveys of households and chronic-care facilities were conducted in Copiah County, Mississippi. The household survey included screening interviews and a complete census. Board-certified neurologists, using defined diagnostic criteria, examined all consenting persons who were either eligible residents of the chronic-care facilities or household members with interview responses suggestive of stroke. In all, 250 stroke survivors were identified, yielding (as of Jan 1, 1978) a point prevalence ratio of 1,060 per 100,000 inhabitants. Age-adjusted prevalence ratios were higher for men and for blacks. Age-specific prevalence ratios increased with advancing age. Nearly 20% of identified stroke survivors had not received inpatient care for that condition.

Functional disability associated with major neurologic disorders. Findings from the Copiah County Study.

The prevalence of functional disability in persons with cerebral palsy, epilepsy, stroke, Parkinson's disease, and severe dementia was assessed in a survey of every household in Copiah County, Mississippi, and all chronic-care institutions serving that county. Of the 23,842 residents evaluated, 246 had moderate to severe functional impairment accompanied by one or more of the aforementioned neurological disorders; 108 were not fully ambulatory; 59 required constant supervision because of cognitive difficulties; 54 were having at least one afebrile seizure monthly; and 25 experienced some combination of these impairments. Overall, prevalence ratios for these impairments increased markedly with age.

Prevalence of Parkinson's disease in the biracial population of Copiah County, Mississippi.

A door-to-door survey of major neurologic disorders was conducted in the essentially biracial population of Copiah County, MS, using a pretested screening questionnaire. All those suspected of having Parkinson's disease were requested to have a neurologic examination by board-certified neurologists. The study also included those living in institutions. The prevalence of Parkinson's disease (age 40+) was 347 per 100,000 inhabitants. No substantial differences in the age-adjusted prevalence ratios by race or by sex were found in the population studied. Age-specific prevalence ratios for Parkinson's disease increase with advancing age. Over 40% of identified cases were newly diagnosed during the study.

Comparison of the prevalence of Parkinson's disease in black populations in the rural United States and in rural Nigeria: door-to-door community studies.

A door-to-door survey of Parkinson's disease (PD) in Copiah County, Mississippi, using a pretested screening procedure (with a high sensitivity for detecting PD), followed by examination of all positives by a senior neurologist, revealed similar prevalence ratios for blacks and whites. The same procedure was applied in the community of Igbo-Ora, Nigeria, a black population of West Africa. To assure uniformity in the procedures and application of the diagnostic criteria, a neurologist from each survey site visited the other site. Among a black population of 3,521 over age 39 in Copiah County, there were 12 cases of PD, with an age-adjusted prevalence ratio of 341/100,000. The comparable figures for Igbo-Ora were as follows: population over age 39 = 3,412; cases of PD = 2; age-adjusted prevalence ratio = 67/100,000.

Prevalence surveys of neurologic disorders: methodologic implications of the Copiah County Study.

This article addresses three questions to be answered during the planning of prevalence surveys of chronic disorders in geographically defined populations: (a) Should personal interviews be used alone (i.e. without accompanying physical examinations) to find and confirm cases in a household population? (b) As an alternative means of identifying cases, is it adequate to review patient records from hospitals and clinics serving the population to be surveyed? (c) Should population members residing in institutions of long-term care be made ineligible for the anticipated survey? Data on major neurologic disorders, obtained from the Copiah County Study, are used to suggest caution in answering any of these questions in the affirmative, since in particular circumstances the consequences for the intended research may be serious or even disastrous. For example, with 42% of Parkinson's disease cases diagnosed for the first time during the study, a casefinding approach solely through medical-care providers would have been highly questionable for that disorder.

Stroke rates in patients with lacunar and large vessel cerebral infarctions.

A stroke registry was developed to determine the value of various clinical data in distinguishing lacunar from large vessel infarctions. Adequate localization was achieved in 98% of 246 patients with brain infarcts. These and 30 transient ischemic attack patients were followed for a median of 1082 days (range 2-1657). Follow-up data on TIA patients were invalidated by evidence of serious underreporting of TIAs in our general population. Among 212 male patients with cerebral infarcts not due to cardiogenic embolism, syphilis, migraine, vasculitis, or other unusual etiologies, 1-, 12-, and 36-month recurrence rates were 23%, 31% and 39% among patients with large vessel anterior circulation infarcts; 15%, 20% and 28% among patients with large vessel posterior circulation infarcts; and 8%, 16% and 21% among patients with lacunar anterior circulation infarcts, respectively. Six patients with posterior circulation lacunes did not experience recurrence. Comparative case fatality data were also compiled. Large vessel infarcts tended to be followed by further large vessel infarcts, usually in the same vascular distribution, whereas lacunar infarcts were not predictive of the type or location of subsequent events.