New and Noteworthy Information—April 2016
Increasing energy output from various physical activities is related to larger gray matter volumes in the elderly, regardless of cognitive status, according to a study published online ahead of print March 11 in the Journal of Alzheimer’s Disease. Subjects were recruited from a population-based longitudinal study of cardiovascular health in people age 65 or older. Researchers analyzed a subsample of 876 subjects for whom data about energy output, cognition, and brain volume were available. Higher energy output from various physical activity types was associated with larger gray matter volumes in frontal, temporal, and parietal lobes, as well as in the hippocampus, thalamus, and basal ganglia. High levels of caloric expenditure moderated neurodegeneration-associated volume loss in the precuneus, posterior cingulate, and cerebellar vermis.
Periodontitis is associated with an increase in cognitive decline in Alzheimer’s disease, independent of baseline cognitive state, according to a study published March 10 in PLoS One. The increase may be mediated through effects on systemic inflammation. In a six-month observational cohort study, 60 participants with mild to moderate Alzheimer’s disease underwent cognitive assessments and blood tests for systemic inflammatory markers. A dental hygienist who was blind to cognitive outcomes assessed participants’ dental health. Participants were followed up at six months, when all assessments were repeated. Periodontitis at baseline was not related to baseline cognitive state, but was associated with a sixfold increase in the rate of cognitive decline, as measured by the Alzheimer’s Disease Assessment Scale–Cognitive subscale, over a six-month follow-up period.
Zika virus infection can cause Guillain-Barré syndrome, according to a study published online ahead of print February 29 in the Lancet. Researchers examined people diagnosed with Guillain-Barré syndrome during an outbreak in French Polynesia, along with two groups of matched controls. In all, 42 patients were diagnosed with Guillain-Barré syndrome during the study period, and 41 of them had anti-Zika virus immunoglobulin M (IgM) or immunoglobulin G. All cases had neutralizing antibodies against Zika virus, compared with 54 of 98 participants in control group 1. Furthermore, 39 cases had Zika virus IgM, and 37 had experienced a transient illness at a median of six days before the onset of neurologic symptoms. Patients with Guillain-Barré syndrome had electrophysiologic findings compatible with acute motor axonal neuropathy type and had rapid evolution of disease.
Radiosurgery may benefit some patients with arteriovenous malformations, according to a study published in the February issue of Stroke. Researchers combined cerebral arteriovenous malformation radiosurgery outcome data from seven institutions participating in the International Gamma Knife Research Foundation. The cohort included 509 patients with a mean age of 40. Favorable outcome was defined as obliteration of malformation, no postprocedural hemorrhage, and no permanent radiation-induced changes. Adverse outcome was defined as any new or worsening neurologic symptoms or death. Arteriovenous malformation was obliterated in 75% of patients. The postradiosurgery hemorrhage rate during the latency period was 0.9% per year. Symptomatic and permanent radiation-induced changes occurred in 11% and 3% of patients, respectively. The rates of favorable outcome, adverse neurologic outcome, permanent neurologic morbidity, and mortality were 70%, 13%, 5%, and 4%, respectively.
A video-game-based cognitive rehabilitation program changes thalamocortical functional connectivity and improves cognition in patients with multiple sclerosis (MS), according to a study published online ahead of print March 8 in Radiology. Researchers randomized 24 patients with MS and cognitive impairment to the cognitive rehabilitation program or a wait-list group. Patients were evaluated with cognitive tests and 3-T resting-state functional MRI at baseline and at eight weeks. Eleven healthy controls also underwent baseline resting-state functional MRI. Patients with MS had lower thalamocortical functional connectivity at baseline than controls. At follow-up, the intervention group had increased functional connectivity in the cingulum, precuneus, and bilateral parietal cortex, and lower functional connectivity in the cerebellum and the left prefrontal cortex, compared with the wait-list group. These changes correlated with cognitive improvement.
Traumatic brain injury (TBI) may be a risk factor for mild cognitive impairment (MCI), but the association between the two may be related to gender and depression, according to a study published online ahead of print February 8 in the Journal of Alzheimer’s Disease. Investigators examined data for 3,187 people with MCI and 3,244 people with normal cognition. TBI was categorized based on lifetime reported TBI with loss of consciousness without chronic deficit. TBI history was a significant predictor of MCI and was associated with increased odds of MCI diagnosis in unadjusted models and adjusted models accounting for age, education, APOE4, and a composite vascular score. The association was largely attenuated after adjustment for history of depression. MCI was diagnosed a mean of 2.3 years earlier among people with TBI.
