New and Noteworthy Information—August 2016
People with epilepsy are at increased risk of autism spectrum disorder, especially if epilepsy appears in childhood, according to a study published July 12 in Neurology. Researchers used the Swedish Patient Register to identify 85,201 individuals with epilepsy, their siblings, and their offspring. Each person with epilepsy was compared with five controls matched for age, sex, calendar period, and county. Patients' siblings and offspring were compared with siblings and offspring of controls. During follow-up, 1.6% of people with epilepsy and 0.2% of controls were diagnosed with autism spectrum disorder. People with epilepsy were at increased risk of future autism spectrum disorder, with the highest risk seen in individuals diagnosed with epilepsy in childhood. Siblings and offspring of patients were at increased risk of autism spectrum disorder, compared with controls.
Among patients with chorea associated with Huntington's disease, deutetrabenazine, compared with placebo, results in improved motor signs at 12 weeks, according to a study published July 5 in JAMA. For this study, 90 adults (mean age, 53.7; 44.4% women) with Huntington's disease and a baseline total maximal chorea score of eight or higher were enrolled from August 2013 to August 2014. Participants were randomized to receive deutetrabenazine or placebo. In the deutetrabenazine group, the mean total maximal chorea scores improved from 12.1 to 7.7, whereas in the placebo group, scores improved from 13.2 to 11.3. In the deutetrabenazine group, the mean 36-Item Short Form physical functioning subscale scores decreased from 47.5 to 47.4, whereas in the placebo group, scores decreased from 43.2 to 39.9.
The estimated suicide rate among people with epilepsy in a large US population exceeds that in the general population, according to a study published online ahead of print June 30 in Epilepsy & Behavior. Among people age 10 and older, researchers identified 972 suicide cases with epilepsy and 81,529 suicide cases without epilepsy in 17 states from 2003 through 2011. Investigators estimated their suicide rates, evaluated suicide risk among people with epilepsy, and investigated suicide risk factors specific to epilepsy by comparing those with and without epilepsy. The estimated annual suicide mortality rate among people with epilepsy was 22% higher than that in the general population. Overall, compared with people without epilepsy, those with epilepsy were more likely to have died from suicide and were twice as likely to poison themselves.
Low-dose methylene blue increases functional MRI (fMRI) activity during sustained attention and short-term memory tasks and enhances memory retrieval, according to a study published online ahead of print June 28 in Radiology. Twenty-six people ages 22 to 62 were enrolled. Researchers performed fMRI imaging with a psychomotor vigilance task and delayed match-to-sample tasks before and one hour after administration of low-dose methylene blue or placebo. Cerebrovascular reactivity effects were measured with the carbon dioxide challenge. Multiple comparison correction also was applied. Administration of methylene blue increased response in the bilateral insular cortex during the psychomotor vigilance task and fMRI response during the short-term memory task involving the prefrontal, parietal, and occipital cortex. Methylene blue also was associated with a 7% increase in correct responses during memory retrieval.
Traumatic brain injury (TBI) with loss of consciousness is associated with an increased risk for clinical and neuropathologic findings of Parkinson's disease, but not Alzheimer's disease, according to a study published online ahead of print July 11 in JAMA Neurology. Researchers retrospectively analyzed data from three prospective cohort studies that included annual or biennial cognitive and clinical testing to identify incident cases of dementia and Alzheimer's disease. Of 7,130 participants, 865 reported a history of TBI with loss of consciousness. In 45,190 person-years of follow-up, 1,537 incident cases of dementia and 117 of Parkinson's disease were identified. No association was found between TBI with loss of consciousness and incident dementia or Alzheimer's disease. TBI with loss of consciousness was associated with incident Parkinson's disease, progression of parkinsonian signs, Lewy bodies, and microinfarcts.
Genetically elevated BMI is associated with risk of multiple sclerosis (MS), which suggests a causal role for obesity in MS etiology, according to an article published June 28 in PLOS Medicine. Researchers used summary statistics from the Genetic Investigation of Anthropometric Traits (GIANT) consortium and the International MS Genetics Consortium (IMSGC). The effect of each single-nucleotide polymorphism (SNP) on MS was weighted by its effect on BMI. Seventy SNPs had genome-wide significance for BMI in GIANT and were investigated for their association with MS risk in the IMSGC. It was found that increased BMI influences MS susceptibility, where a one-standard-deviation increase in genetically determined BMI increased odds of MS by 41%. Sensitivity analyses, including MR-Egger regression, and the weighted median approach provided no evidence of pleiotropic effects.
