Baseline depression was associated with mild cognitive impairment (MCI) and dementia in individuals 65 or older, researchers reported in the December 31, 2012, Archives of Neurology. Depression may coincide with cognitive impairment, but may not precede it, the study authors noted. The investigators studied 2,160 community-dwelling Medicare recipients in New York City. The team defined depression as a score of 4 or more on the Center for Epidemiological Studies Depression scale. MCI, dementia, and progression from MCI to dementia were the study’s main outcome measures. Baseline depression was associated with an increased risk of incident dementia, but not with incident MCI. Participants with MCI and comorbid depression at baseline had a higher risk of progression to dementia, but not Alzheimer’s disease.
Consumption of fructose resulted in a smaller increase in systemic glucose, insulin, and glucagon-like polypeptide 1 levels than consumption of glucose, according to research published in the January 2 JAMA. Glucose ingestion was associated with a significantly greater reduction in hypothalamic cerebral blood flow than fructose ingestion. Researchers performed MRIs of 20 healthy adults at baseline and after ingestion of a glucose or fructose drink. The blinded study had a random-order crossover design. Compared with baseline, glucose ingestion increased functional connectivity between the hypothalamus and the thalamus and striatum. Fructose increased connectivity between the hypothalamus and thalamus, but not the striatum. Fructose reduced regional cerebral blood flow in the thalamus, hippocampus, posterior cingulate cortex, fusiform, and visual cortex.
Research published in the January 7 online Epilepsia provides evidence for a shared genetic susceptibility to epilespsy and migraine with aura. Compared with migraine without aura, the prevalence of migraine with aura was significantly increased among patients with epilepsy who have two or more first-degree relatives with epilepsy. Investigators studied the prevalence of a history of migraine in 730 participants in the Epilepsy Phenome/Genome Project. Eligible participants were 12 or older, had nonacquired focal epilepsy or generalized epilepsy, and had one or more relative epilepsy of unknown cause. The researchers collected information on migraine with and without aura using an instrument validated for individuals 12 and older. The team also interviewed participants about the history of seizure disorders in nonenrolled family members.
Higher exposure to benomyl is associated with an increased risk for Parkinson’s disease, according to an epidemiologic study published in the December 24, 2012, online Proceedings of the National Academy of Sciences. In primary mesencephalic neurons, benomyl exposure inhibits aldehyde dehydrogenase (ALDH) and alters dopamine homeostasis. Investigators tested the effects of benomyl in cell cultures and confirmed that the chemical damaged or destroyed dopaminergic neurons. The researchers also found that benomyl caused the loss of dopaminergic neurons in zebrafish. The ALDH model for Parkinson’s disease etiology may help explain the selective vulnerability of dopaminergic neurons and describe the mechanism through which environmental toxicants contribute to Parkinson’s disease pathogenesis, the authors theorized.
Patients with a history of traumatic brain injury (TBI) and loss of consciousness may have an increased risk for future TBI and loss of consciousness, according to a study published in the November 21, 2012, online Journal of Neurology, Neurosurgery, and Psychiatry. Researchers are conducting an ongoing study of 4,225 nondemented adults age 65 and older. Participants are seen every two years, and 14% have reported a lifetime history of TBI and loss of consciousness. Individuals reporting a first injury before age 25 had an adjusted hazard ratio of 2.54 for TBI and loss of consciousness, compared with a hazard ratio of 3.79 for adults with first injury after age 55.
—Erik Greb