Month of birth is linked to risk of multiple sclerosis (MS), especially in familial cases, according to a study in the December 7 online edition of BMJ. After evaluating 17,874 Canadian patients and 11,502 British patients with MS, researchers found that fewer MS patients were born in November and significantly more were born in May, compared with control subjects. Although an explanation for these results is unclear, one possibility is that climate-related interactions between genes and the environment—occurring during gestation or shortly after birth—influence the risk of the disease in later life, the researchers theorized.

A diet rich in soy and fish can increase production of insulin-degrading enzyme (IDE), which eliminates beta-amyloid, in patients with Alzheimer’s disease, researchers have found. As reported in the December 8 Journal of Neuroscience, investigators observed that deficient insulin signaling correlated with low levels of IDE found in the brains of patients with Alzheimer’s disease and transgenic mice fed a safflower oil–enriched diet. Furthermore, they found that treatment with insulin resulted in increased levels of IDE. The researchers concluded that IDE levels could be manipulated to protect against Alzheimer’s disease through a low-fat diet rich in soy and fish.

New evidence suggests that autoimmunity plays a role in the pathophysiology of narcolepsy, according to an article in the December 11 Lancet. Researchers transferred immunoglobulin G (IgG) from nine patients with narcolepsy and nine healthy controls to the smooth muscle of mice and assessed responses to cholinergic stimulation. They found that mice injected with IgG from patients with narcolepsy displayed “enhanced bladder contractile responses to the muscarinic agonist carbachol and to neuronally released acetylcholine” compared with mice injected with IgG from control subjects. In addition, contraction of sympathetically innervated vas deferens did not differ between male mice injected with IgG from patients with narcolepsy and those injected with IgG from controls.

Researchers have discovered a pathway that connects Broca’s and Wernicke’s areas via a region in the parietal lobe of the cortex known as Geschwind’s territory, as reported in the January Annals of Neurology. Using MRI, the investigators observed that this pathway runs parallel to the arcuate fasciculus and consists of a segment that connects Broca’s area to the inferior parietal lobe and another segment that connects the inferior parietal lobe to Wernicke’s area. The researchers believe that the maturation of Geschwind’s territory coincides with the development of reading and writing skills. They plan on examining the relationship between Geschwind’s territory and autism and dyslexia.

Caffeine consumption seems to be a risk factor for chronic daily headache, according to the December 14 Neurology. Researchers compared 206 people who reported 180 or more headache days per year with 507 controls who reported two to 104 headache days per year. Information on caffeine consumption was obtained through self-report. Researchers found that those with chronic daily headache were more likely to have been high caffeine consumers before the onset of chronic daily headache. Current caffeine consumption was not associated with chronic daily headache. Secondary analysis revealed that associations were confined to younger women and those with chronic episodic headaches.

Exercise appears to be safe for patients with MS and should be recommended for those with mild to moderate disability, according to a study in the December 14 Neurology. Ninety-five patients with MS were randomly assigned to an exercise or control group. Strength and aerobic training were initiated during a three-week inpatient setting and continued for 23 weeks in the patients’ homes. Researchers found that 22% of patients in the exercise group showed improvement in the 7.62-m walk test. Patients in the exercise group also showed improvement in upper extremity endurance compared with controls.

Short-term exposure to social and physical activity improved cognitive performance and subjective sleep quality in 12 elderly patients. As detailed in the December 15 Sleep, patients participated in daily 90-minute sessions of physical activity and social interaction for 14 days and were asked to record the times they went to bed, awoke, or took naps, as well as estimated total sleep time. Researchers assessed the patients’ cognitive and psychomotor performance at the beginning and end of the study and found that cognitive performance improved by 4% to 6% and subjective sleep quality improved as well.

Age-related changes in how the brain responds to estrogen may be responsible for some symptoms of menopause, according to a study in the December 22/29 JAMA. Researchers examined 160 perimenopausal women and observed three patterns of hormonal fluctuations. The first group of women experienced a surge in luteinizing hormone (LH) as a response to increased estrogen. The second group did not experience a surge in LH as a response to increased estrogen. In the third group, estrogen levels remained lower than in the other groups and a surge in LH was not seen. Also, women in this group experienced more hot flashes and night sweats compared with women in the other groups. Researchers said the hormonal pattern in this group reflects alterations in the sensitivity to estrogen in the brain.

Participation in physical activity with at least a medium-low intensity may postpone cognitive decline, according to a study in the December 28 Neurology. Researchers measured the duration and intensity of physical activity in 295 elderly men for 10 years and found that a decrease in duration or intensity of physical activity resulted in a greater cognitive decline by the end of the study period. Cognitive decline was 2.6 times greater in men who had reduced their physical activity by more than 60 minutes per day, compared with those who had maintained the same duration of physical activity. Furthermore, cognitive decline was 3.6 times greater in men who had reduced the intensity of their physical activity, compared with those who had maintained the same level of intensity.

Researchers in Finland have found that two Haemophilus influenzae type b (Hib) vaccine doses in early infancy with a late booster is “efficacious and may practically eliminate Hib meningitis.” As reported in the January 1 BMJ, the investigators believe that keeping at least two months between the first two doses and giving the third as a late booster “is a good compromise” to the more commonly used approach of three doses that has been adopted by many clinicians in Scandinavian countries. “We simply do not know what the ‘protective’ antibody concentrations are,” the investigators reported. “Instead, what we can quantify is a vaccine’s clinical effectiveness.”

Dementia-associated weight loss begins before the onset of dementia symptoms and accelerates by the time a diagnosis is made, according to the January Archives of Neurology. Researchers studied 1,890 Japanese-American men for 32 years. Participants were weighed on six occasions and screened for dementia at the last three examinations; 112 participants were diagnosed with incident dementia. Throughout the final six years of the study, participants without dementia lost an average of 0.22 kg per year, while those with incident dementia lost an additional 0.36 kg per year. The researchers concluded that “weight change and nutritional state in people with dementia should be taken seriously at least from the time of diagnosis if not at earlier stages of more mild cognitive impairment.”

Transplantation of primate embryonic stem cells into areas of the brain where dopamine-producing neurons have degenerated appears to result in diminished parkinsonian symptoms, researchers reported in the January 1 Journal of Clinical Investigation. Investigators generated neurons from primate embryonic stem cells and exposed them to fibroblast growth factor 20. After observing increased dopamine-producing neuron development, the researchers transplanted the neurons into monkeys treated with MPTP, which is considered a primate model for Parkinson’s disease. The “transplanted cells were able to function as dopamine-producing neurons and diminished parkinsonian symptoms,” the investigators stated.

Hormone replacement therapy is associated with an increased risk of stroke, according to a report in the January 21 online edition of BMJ. Researchers analyzed 28 randomized clinical trials involving 39,769 participants and found that hormone replacement therapy was associated with an increased risk of nonfatal stroke, stroke leading to death or disability, and ischemic stroke. It was not, however, associated with hemorrhagic stroke or transient ischemic stroke. The researchers also found that “among subjects who had a stroke, those taking hormone replacement therapy seemed to have a worse outcome.” They concluded that hormone replacement therapy should not be recommended for the prevention of stroke.

The increase in the incidence of autism from 1976 to 1997 may be due to improved awareness, more precise diagnostic criteria, and increased availability of services—but not environmental factors—according to a study in the January Archives of Pediatrics and Adolescent Medicine. From 1980 to 1983, 5.5 per 100,000 children were diagnosed with autism. The incidence of autism increased 8.2-fold, however, from 1995 to 1997; during this time, 44.9 per 100,000 children were diagnosed with autism. The increase occurred after broadening of diagnostic criteria and implementation of federal special education laws. Prior to the development of these new criteria, children with autism may have been misdiagnosed or not identified at all, the investigators noted.

Radiosurgery decreases the risk of hemorrhage in patients with cerebral arteriovenous malformations. As published in the January 13 New England Journal of Medicine, researchers found that of 500 patients with malformations, 42 had hemorrhages before radiosurgery, 23 had hemorrhages during the latency period, and six had hemorrhages after obliteration. According to the investigators, “risk of hemorrhage decreased by 54% during the latency period and 88% after obliteration.”

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