Living in the stroke belt as an adolescent is significantly associated with a high risk of stroke, according to research published online ahead of print April 24 in Neurology. Researchers examined data for 24,544 stroke-free participants in the Reasons for Geographic and Racial Differences in Stroke study. Stroke belt exposure was calculated by combinations of stroke belt birthplace, current residence, and proportion of years in the stroke belt during discrete age categories. Risk of stroke was significantly associated with proportion of life in the stroke belt and with all other exposure periods except birth, ages 31 to 45, and current residence. After adjustment for risk factors, the risk of stroke remained significantly associated only with proportion of residence in the stroke belt during adolescence.

Increased levels of trimethylamine-N-oxide (TMAO), a proatherosclerotic metabolite, are associated with an increased risk of stroke, myocardial infarction, or death, according to research published in the April 25 New England Journal of Medicine. Investigators measured TMAO, choline, and betaine levels in patients who had eaten two hard-boiled eggs and deuterium [d9]-labeled phosphatidylcholine before and after suppressing intestinal microbiota with antibiotics. They also examined the relationship between fasting plasma levels of TMAO and major adverse cardiovascular events during three years of follow-up. Increased plasma levels of TMAO were associated with an increased risk of a major adverse cardiovascular event. An elevated TMAO level predicted an increased risk of major adverse cardiovascular events after adjustment for traditional risk factors, as well as in lower-risk subgroups.

A single-nucleotide polymorphism (SNP) in the ABCA7 gene was significantly linked with an increased risk of Alzheimer’s disease among African Americans, according to research published in the April 10 JAMA. African Americans with this mutation have nearly double the risk of Alzheimer’s disease, but the SNP is not associated with the disease among Europeans. The effect size for the SNP in ABCA7 was comparable with that of the APOE ε4–determining SNP rs429358. Investigators examined data for 5,896 African Americans (1,968 with Alzheimer’s disease and 3,928 controls) who were 60 or older. Data were collected between 1989 and 2011 at multiple sites. The team assessed the association of Alzheimer’s disease with genotyped and imputed SNPs in case–control and in family-based data sets.

The FDA has approved the Precision Spectra Spinal Cord Stimulator (SCS) System, which is designed to provide improved pain relief to patients with chronic pain. The system, manufactured by Boston Scientific (Natick, Massachusetts), includes Illumina 3D software intended to improve physicians’ control of the stimulation field. It is based on a proprietary computer model that takes into account 3-D anatomical structures, including the conductivity of the spinal cord and surrounding tissue. The physician can select a desired location on the spinal cord and prompt the programming software to create a customized stimulation field to mask the patient’s pain. Previous SCS systems included 16 contacts, but the Precision Spectra system includes 32 contacts and is designed to offer more coverage of the spinal cord.

Framingham risk scores may be better than a dementia risk score for assessing individuals’ risk of cognitive decline and targeting modifiable risk factors, according to research published in the April 2 Neurology. Researchers examined data for participants in the Whitehall II longitudinal cohort study. Subjects’ mean age at baseline was 55.6. The investigators compared the Framingham general cardiovascular disease risk score and the Framingham stroke risk score with the Cardiovascular Risk Factors, Aging, and Dementia risk score. Patients underwent cognitive tests of reasoning, memory, verbal fluency, vocabulary, and global cognition three times over 10 years. Compared with the dementia risk score, cardiovascular and stroke risk scores showed slightly stronger associations with 10-year cognitive decline. The differences were statistically significant for semantic fluency and global cognitive scores.

Children born to women who used valproate during pregnancy may have a significantly increased risk of autism spectrum disorder and childhood autism, according to research published in the April 24 JAMA. Investigators used national registers to identify Danish children exposed to valproate during pregnancy and diagnosed with autism spectrum disorders. The researchers analyzed the risks associated with all autism spectrum disorders, as well as childhood autism, and adjusted for potential confounders. The estimated absolute risk after 14 years of follow-up was 1.53% for autism spectrum disorder and 0.48% for childhood autism. The 508 children exposed to valproate had an absolute risk of 4.42% for autism spectrum disorder and an absolute risk of 2.50% for childhood autism. Results changed slightly after considering only the children born to women with epilepsy.

The antisense oligonucleotide ISIS 333611 is a safe treatment for amyotrophic lateral sclerosis (ALS), according to a trial published online ahead of print March 29 in Lancet Neurology. Investigators studied 32 patients with SOD1-positive ALS in a randomized, placebo-controlled, phase I trial. The researchers delivered the drug by intrathecal infusion using an external pump over 11.5 hours at increasing doses (0.15 mg, 0.50 mg, 1.50 mg, and 3.00 mg). Approximately 88% of patients in the placebo group had adverse events, compared with 83% in the active group. The most common events were post-lumbar puncture syndrome, back pain, and nausea. The investigators found no dose-limiting toxic effects or safety or tolerability concerns related to ISIS 333611. No serious adverse events occurred in patients given ISIS 333611.

Thalamic atrophy in patients with clinically isolated syndrome (CIS) is associated with the development of clinically definite multiple sclerosis (MS), according to a study published online ahead of print April 23 in Radiology. Using MRI, researchers assessed 216 patients with CIS at baseline, six months, one year, and two years. MRI measures of progression included new and enlarged T2 lesions and changes in whole-brain, tissue-specific global, and regional gray matter volumes. In mixed-effect model analysis, the lateral ventricle volume, accumulation of new total T2 and new enlarging T2 lesions increase, and thalamic and whole-brain volume decrease were associated with development of clinically definite MS. In multivariate regression analysis, decrease in thalamic volumes and increase in lateral ventricle volumes were associated with the development of clinically definite MS.

Functional MRI (fMRI) can identify pain caused by heat in healthy persons, according to research published in the April 11 New England Journal of Medicine. In four studies of 114 participants, investigators developed an fMRI-based measure that predicts pain intensity, tested its sensitivity and specificity to pain versus warmth, assessed its specificity relative to social pain, and assessed the responsiveness of the measure to the analgesic remifentanil. The neurologic signature distinguished painful heat from nonpainful warmth, pain anticipation, and pain recall with sensitivity and specificity of 94% or more. The signature discriminated between painful heat and nonpainful warmth with 93% sensitivity and specificity. It also distinguished between physical pain and social pain with 85% sensitivity and 73% specificity. The strength of the signature response was substantially reduced after remifentanil administration.

Family history of late-onset Alzheimer’s disease is associated with an increased prevalence of an abnormal cerebral beta-amyloid and tau protein phenotype in patients with mild cognitive impairment (MCI), according to a study published on April 17 in PLOS One. Investigators studied 257 participants (ages 55 to 89) in the Alzheimer’s Disease Neuroimaging Initiative. Subjects were categorized as cognitively normal, having MCI, or having Alzheimer’s disease. Among patients with MCI, CSF Ab42 was lower, t-tau was higher, and t-tau–Ab42 ratio was higher in patients with a family history of Alzheimer’s disease than in patients without. A significant residual effect of family history on pathologic markers in MCI remained after adjusting for APOE e4. The effect of family history was not significant in patients with Alzheimer’s disease.

Most potential migraine triggers are so variable that it may not be possible to identify them without formal experimentation, according to a study published in the April issue of Headache. Investigators examined the similarity of day-to-day weather conditions over four years, as well as the similarity of ovarian hormones and perceived stress over a median of 89 days in nine patients with headache and regular menstrual cycles. A threshold of 90% similarity using Gower’s index identified similar days for comparison. The day-to-day variability in the three headache triggers was substantial enough that finding two naturally similar days for which to contrast the effect of a fourth trigger (eg, drinking wine) occurred infrequently. Fluctuations in weather patterns resulted in a median of 2.3 similar days each year.

Elevated low-density lipoprotein (LDL) cholesterol and altered cholesterol homeostasis may promote neurodegeneration, atherosclerosis, and Alzheimer’s disease by disrupting chromosome segregation, according to research published on April 12 in PLOS One. In a study of mice, investigators observed that high dietary cholesterol induced aneuploidy. In a separate study, the accumulation of intracellular cholesterol was associated with the accumulation of aneuploid fibroblasts, neurons, and glia in patients with Niemann-Pick C1. The researchers also observed that oxidized LDL, LDL, and cholesterol, but not high-density lipoprotein (HDL), induced chromosome mis-segregation and aneuploidy in cultured cells, including neuronal precursors. LDL-induced aneuploidy required the LDL receptor, but not Ab. Cholesterol treatment disrupted the structure of the mitotic spindle, providing a cell biologic mechanism for its aneugenic activity, and ethanol or calcium chelation attenuated lipoprotein-induced chromosome mis-segregation.

The incidence of dementia in central Stockholm may have decreased from the late 1980s to the early 2000s, according to research published online ahead of print April 17 in Neurology. Investigators analyzed data from two cross-sectional surveys of people ages 75 or older. One study was conducted from 1987 to 1989 and included 1,700 participants; the other was conducted from 2001 to 2004 and included 1,575 subjects. The team inferred the incidence of dementia according to its relationship with prevalence and survival. The adjusted odds ratio of dementia in the later study versus the earlier study was 1.17. The multiadjusted hazard ratio of death in the later study versus the earlier study was 0.71 in subjects with dementia, 0.68 in those without dementia, and 0.66 in all participants.

—Erik Greb
Senior Associate Editor

New and Noteworthy Information—May 2013