HIV infection is associated with a significantly lower risk of developing multiple sclerosis (MS), according to a study published online ahead of print August 4 in the Journal of Neurology, Neurosurgery, & Psychiatry. Researchers investigated episodes of hospital care between 1999 and 2011 for patients with HIV. Compared with people who did not have HIV, patients with HIV were 62% less likely to develop MS. After more than a year between the two diagnoses, HIV-positive patients were 75% less likely to develop MS. “If subsequent studies demonstrate [that] there is a causal protective effect of HIV or its treatment, and if the magnitude of it proves to be similar … this would be the largest protective effect of any factor yet observed in relation to the development of MS,” the investigators concluded.

Colds and other minor infections may temporarily increase stroke risk in children, according to a study published online ahead of print August 20 in Neurology. Using the Kaiser Permanente database of 2.5 million children, researchers identified 102 children who had had an acute ischemic stroke and compared them with 306 children without stroke. Medical records for the children who had had a stroke were reviewed for minor infections for two years before their strokes. Ten (9.8%) of the 102 children with stroke had visited a physician for an infection within three days of the stroke. In comparison, two controls (0.7%) had an infection during the same time period. “Proposed mechanisms for the link between minor infection and stroke in adults include an inflammatory-mediated prothrombotic state and chronic endothelial injury,” the investigators theorized.

Peripheral pulse monitoring in patients with stroke accurately distinguishes atrial fibrillation from normal heart rhythm, investigators reported in the August 12 issue of Neurology. The prospective study included 256 patients with acute ischemic stroke, as well as the patients’ relatives. Subjects were taught to measure the patient’s pulse to detect atrial fibrillation; measurements from the participants and health care professionals were compared with recordings of electrical activity in the heart. Fifty-seven patients had irregular heartbeats. Measurement of the peripheral pulse by health care professionals had a diagnostic sensitivity of 96.5%, compared with 76.5% for the patients’ relatives, regarding the detection of atrial fibrillation. The specificity was 94.0% for health care professionals and 92.9% for patients’ relatives. Self-measurements were performed by 89.1% of patients with a diagnostic sensitivity of 54.1% and 96.2% specificity.

Reducing smoking among people in a low socioeconomic position and among those with hypertension may reduce social inequality stroke incidence, researchers reported online ahead of print August 14 in Stroke. The findings are based on data from 68,643 adults between ages 30 and 70 who were grouped into low, medium, and high education levels and assessed for smoking status and blood pressure level. About 16% of men and 11% of women had a high risk of stroke because of low education level, high blood pressure, and smoking. Smokers with low education had a greater risk of stroke than smokers with high education, regardless of their blood pressure. About 10% of men and 9% of women at high risk had an ischemic stroke during follow-up. Overall, men had a higher risk of stroke than women, and their risk increased with age.

Motoric cognitive risk syndrome (MCR), a predementia syndrome characterized by slow gait and cognitive complaints, is common in older adults and is a strong and early risk factor for cognitive decline, according to a study published online ahead of print July 16 in Neurology. Among 26,802 participants from 22 cohorts, 2,808 subjects met MCR criteria. MCR prevalence was higher among older individuals, but there were no sex differences. MCR predicted the risk of developing incident cognitive impairment (adjusted hazard ratio, 2.0); in individual cohorts the adjusted hazard ratios ranged from 1.5 to 2.7. MCR also predicted dementia in the pooled sample (adjusted hazard ratio, 1.9). “MCR criteria can be easily applied in clinical settings with simple questions about cognitive complaints and timing gait; 90% of participants had walking timed over fixed distances without requiring major resource commitments,” the investigators stated.

The FDA has approved Plegridy (peginterferon beta-1a) for patients with relapsing forms of multiple sclerosis (MS). Approval of the drug is based on results from the ADVANCE study of more than 1,500 patients with MS. The drug can be administered subcutaneously with an autoinjector or a prefilled syringe. Dosed once every two weeks, the drug significantly reduced annualized relapse rate at one year by 36%, compared with placebo. Plegridy reduced the risk of 12-week confirmed disability progression by 38%, compared with placebo. The drug also significantly reduced the number of new gadolinium-enhancing lesions by 86% and decreased the number of new or newly enlarging T2-hyperintense lesions by 67%, compared with placebo. Common adverse reactions include injection-site reaction and flu-like illness. The drug is manufactured by Biogen Idec, which is headquartered in Cambridge, Massachusetts.

In patients who are hospitalized for surgery, perioperative atrial fibrillation is associated with an increased long-term risk of ischemic stroke, according to a study published in the August 13 issue of JAMA. Researchers studied 1,729,360 patients hospitalized for surgery between 2007 and 2011. Perioperative atrial fibrillation was documented in 24,711 patients (1.43%) during the index hospitalization. After discharge, 13,952 patients (0.81%) had an ischemic stroke. One year after hospitalization for noncardiac surgery, cumulative rates of stroke were 1.47% in patients with perioperative atrial fibrillation and 0.36% in people without atrial fibrillation. One year after cardiac surgery, cumulative rates of stroke were 0.99% in patients with perioperative atrial fibrillation and 0.83% in patients without atrial fibrillation. The association with stroke was stronger for perioperative atrial fibrillation and noncardiac surgery, compared with cardiac surgery.

Approximately one-third of cases of Alzheimer’s disease worldwide might be attributed to potentially modifiable risk factors, investigators reported in the August issue of Lancet Neurology. An international team of researchers used relative risks from existing meta-analyses to estimate the population-attributable risk (PAR) of Alzheimer’s disease worldwide and in the United States, Europe, and the United Kingdom for seven potentially modifiable risk factors. Worldwide, the highest estimated PAR was for low educational attainment. In the US, Europe, and UK the highest estimated PAR was for physical inactivity. Assuming the risk factors’ independence, the combined worldwide PAR for the seven risk factors was 49.4%, which accounts for 16.8 million of the 33.9 million cases. Adjustment for the association between the risk factors decreased the estimate to 28.2%, which equates to 9.6 million cases.

The FDA has approved Belsomra (suvorexant) for adults with insomnia who have difficulty falling and staying asleep. The drug is the first approved orexin receptor antagonist. Orexins are involved in regulating the sleep–wake cycle and play a role in promoting arousal. In clinical trials, Belsomra (Merck; Whitehouse Station, New Jersey) was superior to placebo for reducing sleep latency and improving sleep maintenance, as assessed objectively by polysomnography and subjectively by patient-estimated sleep latency. Belsomra should be taken no more than once per night, within 30 minutes of going to bed, with at least seven hours remaining before the planned time of waking. The total dose should not exceed 20 mg once daily. The most commonly reported adverse reaction among clinical trial participants taking Belsomra was drowsiness.

A clinical diagnosis of Parkinson’s disease identifies patients who will have pathologically confirmed Parkinson’s disease with a sensitivity of 88% and specificity of 68%, researchers reported in the July 29 issue of Neurology. Investigators analyzed data from an aging study to determine the predictive value of clinical diagnosis of Parkinson’s disease using two diagnostic confidence levels: possible and probable Parkinson’s disease. Approximately 26% of patients diagnosed with possible Parkinson’s disease were neuropathologically confirmed as having Parkinson’s disease; 82% of patients diagnosed with probable Parkinson’s disease were confirmed as having Parkinson’s disease. Researchers calculated a 26% accuracy rate for clinical diagnosis of Parkinson’s disease in untreated or not clearly responsive subjects, a 53% accuracy rate in early Parkinson’s disease responsive to medication (less than five year’s duration), and a greater than 85% diagnostic accuracy rate for longer duration, medication-responsive Parkinson’s disease.

Depressive symptoms in old age are associated with cognitive decline that is independent of dementia, according to a study published in the August 19 issue of Neurology. Investigators monitored 1,764 participants with an average age of 77 who had no thinking or memory problems at the start of the study. Participants were screened every year for symptoms of depression and were evaluated for their memory and thinking skills for a mean of 7.8 years. A total of 922 (52%) participants developed mild cognitive impairment, and 315 (18%) developed dementia. Overall, having a higher level of depression symptoms was associated with more rapid decline in thinking and memory skills, which accounted for 4.4% of the difference in decline that could not be attributed to the level of damage in the brain.

Researchers may have found a potential genetic link between epilepsy and neurodegenerative disorders, according to a study published in the July 29 Proceedings of the National Academy of Sciences. The investigators observed that seizure-prone prickle mutant flies have behavioral defects and electrophysiologic defects similar to those of other fly mutants used to study seizures. Altering the balance of two forms of the prickle gene disrupted neural information flow and caused epilepsy. The researchers also observed that reducing either of two motor proteins responsible for directional movement of vesicles along the tracks of structural proteins in axons could suppress seizures. “This is, to our knowledge, the first direct genetic evidence demonstrating that mutations in the fly version of a known human epilepsy gene produce seizures through altered vesicle transport,” stated the authors.

—Kimberly Williams

New and Noteworthy Information—September 2014