Strains of the ulcer-causing bacteria Helicobacter pylori may play a key role in certain kinds of stroke, asserts research in the July 9 Circulation. Investigators found that specific strains of H pylori were more prevalent in the blood of patients who had an atherosclerotic stroke. Researchers compared different strains of H pylori in the bloodstream of 138 patients with large-vessel stroke, 61 patients with cardioembolic stroke, and 151 healthy volunteers and found that the prevalence of H pylori infection in all test subjects was comparable. However, the presence of cytotoxin-associated gene-A (CagA) was significantly higher in the large-vessel stroke patients (42.8%) than in both the cardioembolic stroke group (19.7%) and control group (17.9%). Researchers found that only CagA-positive strains of H pylori are associated with ischemic stroke, and that this association is confined to patients with atherosclerotic stroke.

Researchers have determined that while 30% of patients taking both high and low doses of dopamine agonists for Parkinson’s disease experience sleep attacks, the prediction, prevention, and treatment of these attacks remain unsolved. The study, found in the June 22 BMJ, examined factors including the nature of the sleep events, Epworth sleepiness scale score, prevalence of sleep events, and treatment of sleep events. No clear patterns emerged when taking these factors into account, making it difficult to predict who is most susceptible to sleep attacks. Due to the relative rarity of sleep attacks while driving, researchers suggest that cautioning patients that such a risk exists, rather than banning them from driving, is sufficient until more data are available.

A drug that boosts memory for patients with Alzheimer’s disease may also enhance the performance of airplane pilots, according to a study published in the July 9 Neurology. Eighteen pilots (average age, 52) conducted seven practice flights on a flight simulator designed to train them to perform a complex series of maneuvers. After these initial flights, half the pilots were given donepezil for 30 days, while the other half were given a placebo. The pilots took the simulator test twice more to see if they had retained the training. The pilots who had taken donepezil performed better than those who took the placebo. Researchers caution that these results need to be confirmed in larger studies, when factors such as side effects can be taken into account.

Acute hyperglycemia has adverse effects on stroke outcome, according to a study in the July Annals of Neurology. Researchers analyzed the relationship between hyperglycemia, lactic acidosis, and stroke outcome in 63 acute stroke patients. In 40 patients with acute perfusion-diffusion lesion mismatch, acute hyperglycemia was correlated with reduced salvage of mismatch tissue from infarction, greater final infarct size, and worse functional outcome. These correlations were not related to baseline stroke severity, lesion size, or diabetic status. Researchers also found that higher acute blood glucose in patients with perfusion-diffusion mismatch was associated with greater acute-subacute lactate production, which was independently associated with reduced salvage of mismatch tissue.

While it has been shown that feeding tubes neither delay death nor improve quality of life for nursing home patients with severe dementia, the use of feeding tubes varies widely throughout the country. Joan Teno, MD, and colleagues analyzed the medical records of 385,741 nursing home residents with severe dementia. Nationwide, about 18% of nursing home residents with severe dementia had a feeding tube, yet in some states the use of feeding tubes is more than 10 times the rate of other states. The only identified factor that was closely associated with the interstate differences was physician use of do not resuscitate (DNR) orders. “It may be that doctors are giving up on their patients with DNRs, so don’t recommend further treatment,” said Dr. Teno. This underscores a greater need for discussion about decisions to use feeding tubes. The study was published in the June 26 JAMA.

Inosine, a naturally occurring chemical, can induce axon growth within the brain and spinal cord and thereby improve motor function after stroke in animal models, according to a study in the June 25 Proceedings of the National Academy of Sciences. Inosine was shown to activate nerve cells in undamaged parts of the brain to grow into areas that had lost their normal connections as a result of a stroke. This rewiring partially compensated for the loss of the original connections and resulted in significant improvement in several types of behavior compared with rats that did not receive inosine.

Canadian researchers have found no discernible link between the incidence of stroke and the weather, according to a report in the July Stroke. The research took place in Calgary, Alberta, where geological and atmospheric factors frequently cause rapid and extreme weather variations, causing what is known as the “Chinook wind.” Investigators obtained hourly weather data for 1996 through 2000, and compared average daily strokes on Chinook and non-Chinook days with average daily temperatures, humidity, barometric pressure, and wind speed. They recorded 182 Chinook days and more than 3,000 strokes but found no association between stroke and weekly, monthly, or seasonal weather changes, or between any type of stroke or weather parameter.

New recommendations regarding the use of brain imaging in preterm and term infants have been released by the American Academy of Neurology and the Child Neurology Society. All preterm neonates born at less than 30 weeks gestation should receive screening cranial ultrasonography when they are between 7 and 14 days old, and the screening should be repeated when they have reached 36 to 40 gestational weeks. The screening is recommended to detect lesions, such as major hemorrhages or white matter damage, that might affect the infant’s neurodevelopment. In addition, when a full-term infant with coma or seizures has evidence of birth trauma, computed tomography should be performed to detect any hemorrhages. The guidelines were published in the June 25 Neurology.

Elevated cholesterol is a risk factor for stroke death in younger women, particularly African-American women, according to an analysis in the July Stroke. Researchers followed participants in eight long-term prospective studies, evaluating stroke risk factors in 24,343 women, ages 30 to 97, with no history of heart attack, coronary chest pain, or stroke. Cholesterol proved to be a significant risk factor for stroke death in women younger than 55 at enrollment. The risk for ischemic stroke increased by 23% across the spectrum of cholesterol levels. In addition, the study showed that stroke risk for African-American women was 76% greater in the younger age-group and 48% greater in the older age-group. Conversely, cholesterol did not predict hemorrhagic stroke mortality in younger women, nor did it have a significant association with stroke death in older women.

The areas of the brain responsible for sensation in the mouth, lips, and tongue are more active in obese people than in control subjects, according to a report from Brookhaven National Laboratory. Researchers discovered that obese people have fewer brain receptors for dopamine, which implies that they may eat to stimulate their reward circuits. The investigators measured regional brain metabolism in 10 severely obese patients and 20 controls and discovered higher metabolic activity in the regions of the parietal cortex, where somatosensory input from the mouth, lips, and tongue is received. The enhanced sensitivity could account for the powerful appeal and significance that food has for obese individuals. The study appears in the July 2 NeuroReport.

Patients are more likely to survive a subarachnoid hemorrhage if they are admitted to a hospital that treats these strokes more often. Investigators searched admission records and discharge abstracts for subarachnoid hemorrhage in a database of all non-federal hospitals in California between 1990 and 1999. Data on 12,804 patients admitted to 390 hospital emergency departments for subarachnoid hemorrhage were examined, and outcomes were compared with each facility’s annual subarachnoid hemorrhage case rate. Researchers discovered that mortality was 49% in hospitals with the fewest subarachnoid hemorrhage cases, and 32% in those with the most cases. In addition, factors such as length of stay and cost did not alter the correlation between mortality and treatment volume. The study was published in the July Stroke.

There may be a correlation between active human herpesvirus 6 infection (HHV-6) and multiple sclerosis, according to a study in the June Archives of Neurology. Researchers analyzed 149 blood and serum samples (103 from patients with relapsing-remitting multiple sclerosis and 46 from healthy blood donors). They used quantitative real-time polymerase chain reaction to determine whether HHV-6 and its variants were present. The investigators found HHV-6 DNA in blood cells of 53.4% of patients and 30.4% of healthy blood donors. In addition, no healthy blood donors had serum samples that contained HHV-6 DNA, but 14.6% of the samples from patients with multiple sclerosis contained HHV-6. However, researchers also admit that despite “the accumulated evidence, it is risky to infer that a virus with such a low prevalence has a major role in the pathogenesis of multiple sclerosis.”

Immunization with a non-toxic, genetically engineered prion delayed the onset of brain disease in mice, according to a study in the July American Journal of Pathology. Although the vaccine, based on the normal sequence of amino acids for the prion protein, did not prevent brain disease, the study showed that it could break the body’s tolerance to prion protein by inducing an immune response in the form of antibodies in mice. Higher antibody levels were found in the animals that resisted the disease for the longest time, implying that these antibodies can potentially shield the body from the disease.

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