Mysteriously, Risk Of Stroke Shown To Have Geographic Determinants

eMax Health

A new study published in the December issue of Neurology reports on the strong influence of birthplace on stroke risk. A person born in the “Stroke Belt" will continue to have a higher risk of stroke even if they have moved away.

M. Maria Glymour, ScD, of Harvard School of Public Health, and colleagues evaluated stroke mortality rates for United States–born black and white people aged 30–80 years for 1980, 1990, and 2000. This data was defined by birth state, state of adult residence, race, sex, and birth year.

Four “Stroke Belt” (SB) exposure categories were defined: born in a SB state (North Carolina, South Carolina, Georgia, Tennessee, Arkansas, Mississippi, or Alabama) and lived in the SB at adulthood; non-SB born but SB adult residence; SB-born but adult residence outside the SB; and did not live in the SB at birth or in adulthood (reference group).

The researchers findings noted an elevated stroke mortality associated with both SB birth and, independently, SB adult residence. The highest risk was found to be in persons who were born in the SB and continued to live there as an adult.

For African-Americans born in the Stroke Belt and living there as adults, the odds ratio for stroke mortality was 1.55 in 1980, 1.47 in 1990, and 1.34 in 2000. For white individual in the same group, the odds ratios were 1.45 in 1980, 1.29 in 1990, and 1.34 in 2000.

For reasons that have eluded explanation, residents of the southeastern U.S. historically have had a 20% to 50% greater risk of stroke mortality compared with residents living elsewhere in the country. This influence of residence in the Stroke Belt has little association with conventional stroke risk factors, social resources, or access to medical care.

Future studies of stroke risk should include detailed information about movement from one region to another. Such information might show whether people who move have different risk patterns help identify more precisely the point in life when stroke risk begins to increase. That information could aid the development of risk-reduction strategies specific to different regions of the country, the authors concluded.

Restoring Vision to Stroke Victims
Story from the Democrat and Chronicle

Patients who are partially blind after a stroke may be able to retrain their brain after doing months of eye exercises on a computer, according to a small study by University of Rochester researchers.

The study, published in the April 1 issue of the Journal of Neuroscience, found that people who did vigorous exercises every day for several months could coax the healthy regions of their brains to take in visual information, making up for other parts of the brain damaged by strokes.

Neuroscientist Dr. Krystel Huxlin, who led the study at the University of Rochester Eye Institute, said she was surprised by the research results because scientists had long believed that patients could not recover from the type of visual damage done by strokes. Many people are one-quarter to one-half blind after strokes, and though rehabilitation is common for relearning speech and movements, patients rarely receive visual training.

Huxlin studied four women and three men in their 30s to 80s, who had a stroke eight to 40 months before the experiment. All were partially blind and had substantial damage in the primary visual cortex of their brains, meaning their eyes could take in visual information that they could not consciously see.

During the study, they were told to "watch" a group of about 100 small dots move right or left across a computer screen. Though the patients were not aware they could see the dots, they would guess which direction the dots were moving and could improve their success rates over time when told when they've made a correct choice. Eventually, they became aware of the dots and their movements, as their brains relearned how to take in the visual information, the study found.

When they improved, researchers moved the dots deeper into their blind areas and could coax the brain to see more areas.

The five patients who completed the training had significantly improved vision, and several could drive again, shop and exercise after the experiment.

The University of Rochester has filed a patent on the technology.