“Our results show that spatial learning in humans can be enhanced by electrical stimulation of the entorhinal region,” wrote Dr. Suthana. The finding “suggests that improvement could occur in patients with other memory impairments (eg, Alzheimer’s disease),” she added. The fact that stimulation was applied during the learning phase of the trial indicates that “stimulation may not need to be applied continuously, but only when patients are attempting to learn important information.”
Four patients experienced theta phase resetting in the hippocampus while they received entorhinal stimulation. “Our preliminary results support the hypothesis that stimulation that enhances memory also induces theta-phase resetting,” concluded the researchers.
“The potential application of deep-brain stimulation in amnestic disorders is enticing,” wrote Sandra E. Black, MD, member of the Collaborative Program in Neuroscience at the University of Toronto, in an accompanying editorial. Dr. Suthana’s technique could benefit patients with stable hippocampal injuries, such as those resulting from stroke. In addition, deep-brain stimulation could one day improve memory in patients with early-stage Alzheimer’s disease, wrote Dr. Black.
Suthana N, Haneef Z, Stern J, et al. Memory enhancement and deep-brain stimulation of the entorhinal area. N Engl J Med. 2012;366(6):502-510.
Black SE. Brain stimulation, learning, and memory. N Engl J Med. 2012;366(6):563-565.
Traditional Risk Factors Increase Likelihood of Cardiovascular Disease
Traditional risk factors strongly influence a person’s lifetime risk of cardiovascular disease, according to a study published in the January 26 issue of the New England Journal of Medicine. A patient’s risk of heart attack or stroke is far greater if he or she has one or more risk factors that are not optimal than it is if all of his or her risk factors are optimal. The effect of risk factors is similar for blacks and whites, regardless of birth decade.
Studies of heart disease traditionally have focused on white men, but Jarett Berry, MD, Assistant Professor of Internal Medicine at the University of Texas Southwestern Medical Center in Dallas, and colleagues examined the risk of cardiovascular disease among black and white adults of both genders. The group analyzed data from 18 cohort studies that included 257,384 patients whose risk factors were measured at ages 45, 55, 65, and 75. The investigators grouped participants into five categories and calculated the lifetime risks of cardiovascular disease for members of each category at each age.
Traditional risk factors include blood pressure, cholesterol level, smoking status, and diabetes status. A patient with systolic blood pressure lower than 120 mm HG and diastolic blood pressure lower than 80 mm HG, cholesterol level of less than 180 mg/dL, nonsmoking status, and nondiabetic status was considered to have an optimal risk-factor profile.
Of male patients who were 55, those with an optimal risk-factor profile had a 4.7% risk of cardiovascular disease through age 80, compared with a 29.6% risk for patients with two or more major risk factors. For 55-year-old women, those with an optimal risk-factor profile had a 6.4% risk of cardiovascular disease through age 80, compared with a 20.5% risk for patients with two or more major risk factors. Patients with optimal risk-factor profiles also had lower lifetime risks of fatal coronary heart disease or nonfatal myocardial infarction, and fatal or nonfatal stroke.
The study results “may be important in estimating the future burden of cardiovascular disease in the general population,” said Dr. Berry. “Efforts to lower the burden of cardiovascular disease will require prevention of the development of risk factors (primordial prevention) rather than the sole reliance on the treatment of existing risk factors (primary prevention),” he concluded.
Berry JD, Dyer A, Cai X, et al. Lifetime risks of cardiovascular disease. N Engl J Med. 2012;366(4):321-329.
Imaging Technique Identifies Patients at Risk for Future Cognitive Decline
The patterns according to which the chemical marker [18F]FDDNP binds within the brain can predict whether a person will develop cognitive impairment or Alzheimer’s disease, according to a study published in the February issue of Archives of Neurology. The marker also could help researchers evaluate the efficacy of measures intended to prevent or slow cognitive decline.
Gary W. Small, MD, Parlow-Solomon Professor on Aging at the David Geffen School of Medicine at the University of California, Los Angeles, and his colleagues conducted a two-year, longitudinal follow-up study to determine whether [18F]FDDNP brain regional binding values increase as cognitive decline progresses. The researchers also sought to understand whether [18F]FDDNP binding values predicted future cognitive decline.
Dr. Small’s group selected 43 volunteers with a median age of 64. Of the volunteers, 21 had mild cognitive impairment, and 22 had normal aging, but none had dementia. The investigators performed laboratory tests and structural imaging scans on the patients to rule out causes of cognitive impairment such as stroke and tumor. At baseline and at follow-up, each patient received a bolus injection of [18F]FDDNP through an indwelling venous catheter, and the researchers performed consecutive dynamic PET scans for one hour.