Validation of the brain injury associated visual impairment - impact questionnaire (BIVI-IQ).

PURPOSE: The Brain Injury associated Visual Impairment - Impact Questionnaire (BIVI-IQ) was developed to assess the impact of post-stroke visual impairment. The development of the questionnaire used robust methods involving stroke survivors and clinicians. The aim of this study was to assess the validity of the BIVI-IQ in a stroke population. METHODS: Stroke survivors with visual impairment were recruited from stroke units, outpatient clinics and non-healthcare settings. Participants were asked to complete questionnaire sets on three separate occasions; the BIVI-IQ at each visit with additional questionnaires at baseline and visit 2. Vision assessment and anchor questions from participants and clinicians were collected. The analysis included assessment of missing data, acceptability, Rasch model analysis, test-retest reliability, construct validity (NEI VFQ-25, EQ-5D-5L) and responsiveness to change. RESULTS: 316 stroke survivors completed at least one questionnaire of the 326 recruited. Mean age was 67 years and 64% were male. Adequate fit statistics to the Rasch model were reached (χ2 = 73.12, p = 0.02) with two items removed and thresholds of two adjusted, indicating validity and unidimensionality. Excellent test-retest reliability was demonstrated (ICC = 0.905) with a 3-month interval. Construct validity was demonstrated with a strong significant correlation to the NEI VFQ-25 (r = 0.837, p < 0.01). The BIVI-IQ also demonstrated responsiveness to change with significant differences identified between groups based on participant and clinician anchor questions (X2 = 23.29, p < 0.001; X2 = 24.56, p < 0.001). CONCLUSION: The BIVI-IQ has been shown to be valid and practical for 'everyday' use by clinicians and researchers to monitor vision-related quality of life in stroke survivors with visual impairment.

Study organization in the Canadian Study of Health and Aging.

The Canadian Study of Health and Aging was a complex undertaking that faced management challenges not encountered by smaller-scale projects. The study followed 10,263 elderly people in 18 study centers spanning six time zones; it was administered in two languages, and over 70 investigators were involved. The data collected from each participant were not fixed, but varied according to the results of earlier testing. The data could include a screening interview, a self-completed risk factor questionnaire, an interview with a relative, a clinical examination, neuropsychological testing, blood samples, and neuroimaging. This report describes the approach taken to organize the study, to track participants, and to monitor adherence to the study protocol. It also describes the human organizational aspects, including systems for staff training, for communicating among study centers, and for coordinating the publication of results. The discussion proposes some guiding principles for administering multicenter studies.

Correlates of nonparticipation in the Canadian Study of Health and Aging.

Correlates of nonparticipation in the community interview component of the Canadian Study of Health and Aging and their impact on bias in the results were analyzed. Characteristics of study subjects, their habitats, and encouragement techniques were analyzed to identify correlates of variation in response rates across the 18 study centers. Refusal rates from 14% to 41% varied by age, gender, city size, number of subjects and length of time for enrollment, and method of approach. Cognitively impaired subjects had higher refusal rates which affected prevalence estimates. At one study site, efforts to "convert" subjects who initially refused to participate in the survey were successful with 26% of those who were recontacted.

Marital status, dementia and institutional residence among elderly Canadians: the Canadian Study of Health and Aging.

The association between marital status and mortality is well known; marital status has also been related to morbidity. In this paper, we examine the importance of marital status in relation to the presence or absence of dementia and to institutional residence, using data from the Canadian Study of Health and Aging. Three groups are compared: married, single and previously married. We show that the age-standardized prevalence of dementia and the proportions of elderly Canadians living in institutions with and without dementia are highest among single people and are also high for those who were previously married. These associations hold true for both women and men, but the relation between marital status and institutionalization is much stronger for men. Possible explanations and implications for the future care of the elderly are discussed.

Underreporting of cancer in medical surveys: a source of systematic error in cancer research.

Systematic errors occur in the reports of disease frequency derived from health surveys based on questionnaire interviews. Five hundred and thirty-three persons with clinically and histologically confirmed disease in a case-control study of cancer were interviewed in their homes by carefully trained interviewers using a standardized questionnaire interview schedule. Comparisons of the information obtained by interview about past history of cancer with cancer registry and hospital medical record information about the same people revealed serious underestimates of correct frequency and wide variation in the rates of correct reporting. The findings reported here and elsewhere add support to an essential requirement in medical survey research: the completeness and accuracy of responses in health interview surveys must be verified and the methods of verification must be reported before the results can be interpreted with confidence.

The occupation of fishing as a risk factor in cancer of the lip.

To study the role of commercial fishing and related factors in the development of lip cancer, a project that included a case-control study and a cohort analysis was undertaken in Newfoundland. Household survey data were linked with cancer-registry and census data. In comparison with other males, fishermen had a probability of development of lip cancer that was 1.5 times higher (by the case-control method, P less than 0.05) or 4.4 times higher (by cohort analysis, P less than 0.001). Despite the effect of pipe smoking, "outdoorness" and age on the development of lip cancer in general, the occupation of fishing was an additional, independent contribution to the risk. Unexpectedly, using the mouth as a third hand to handle tar-coated nets seemed to protect fishermen from the disease. It was not possible to attribute the higher risk to a particular work activity, nor was a specific responsible carcinogen identified.