One third of patients with pathologically confirmed early-onset Alzheimer’s disease presented with atypical symptoms, and 53% of patients with nonamnestic presentations were initially misdiagnosed, according to a study in the May 17 Neurology. Researchers conducted a retrospective review of clinical data from patients with confirmed early-onset Alzheimer’s disease to determine the frequency and types of incorrect diagnoses. The majority of these cases were diagnosed with other types of dementia, including pseudodementia with depression, semantic dementia, and primary progressive aphasia. “Early-onset Alzheimer’s disease diagnosis often represents a challenge because of the high frequency of atypical presentations,” the study authors wrote. More than one-third (37.5%) of patients presented with atypical symptoms other than memory problems; the most prevalent of these was behavioral/executive dysfunction.

Neuronal activity may be a potential mechanism for vulnerability to amyloid-β deposition in certain areas of the brain, researchers reported in the May 1 online Nature Neuroscience. The investigators examined endogenous neuronal activity in mice with Alzheimer’s disease and determined that this activity regulates the regional concentration of interstitial fluid amyloid-β, which drives local aggregation of amyloid-β. Using unilateral vibrissal stimulation in the contralateral barrel cortex, they found that activity increased interstitial fluid amyloid-β. Unilateral vibrissal deprivation decreased interstitial fluid amyloid-β deposition; long-term deprivation also decreased amyloid plaque formation and growth. “Our results suggest a mechanism to account for the vulnerability of specific brain regions to amyloid-β deposition in Alzheimer’s disease,” the authors concluded.

A newly confirmed genetic risk allele of the clusterin gene contributes to white matter degeneration in young adults and may increase the risk for Alzheimer’s disease later in life, according to results published in the May 4 Journal of Neuroscience. Investigators used diffusion-tensor MRI to scan the brains of 398 healthy young adults (mean age, 23.6) and to evaluate whether the C-allele clusterin risk variant was associated with lower white matter integrity. “Each C-allele copy of the clusterin variant was associated with lower fractional anisotropy—a widely accepted measure of white matter integrity—in multiple brain regions,” the authors wrote. These regions included the splenium of the corpus callosum, the fornix, cingulum, and superior and inferior longitudinal fasciculi in both brain hemispheres. “Young healthy carriers of the clusterin gene risk variant showed a distinct profile of lower white matter integrity that may increase vulnerability to developing Alzheimer’s disease later in life,” the researchers concluded.

A higher BMI may improve survival in patients with amyotrophic lateral sclerosis (ALS). As published in the May 23 online Muscle & Nerve, investigators aimed to determine whether cholesterol levels are an independent predictor of ALS survival. They measured cholesterol levels in 427 people with ALS from three clinical trial databases and found that the low-density and high-density lipoprotein level ratio did not decrease over time, even though BMI significantly declined. “After adjusting for BMI, forced vital capacity, and age, the lipid ratio was not associated with survival,” the investigators wrote. The highest survival rate, though, was found among patients with a BMI between 30 and 35, or mild obesity. “We found that dyslipidemia is not an independent predictor of survival in ALS,” the researchers concluded, whereas, “BMI is an independent prognostic factor for survival after adjusting for markers of disease severity.”

Patients with a history of intracerebral hemorrhage (ICH) should avoid using statins for prevention of ischemic cardiac and cerebrovascular disease, according to a study in the May Archives of Neurology. Statins are widely prescribed for disease prevention, the authors noted, and “although serious adverse effects are uncommon, results from a recent clinical trial suggested increased risk of ICH associated with statin use.” To determine if statin therapy should be avoided in patients with a baseline elevated risk of ICH, investigators evaluated the risks and benefits of the therapy in patients with prior ICH using clinical parameters such as hemorrhage location (deep or lobar). For survivors of ICH both with and without prior cardiovascular events, the benefits of statin therapy were not strong enough to offset the increased risk for hemorrhage recurrence.

Adverse changes in sleep duration are associated with poorer cognitive function in middle-aged adults, per a study in the May 1 Sleep. Researchers conducted cross-sectional studies of women and men (age range, 45 to 69) to examine the effect of changes in sleep duration on cognitive function. Participants’ cognitive function was assessed at baseline, and their sleep duration on an average weeknight was measured once at baseline and again an average of 5.4 years later. After adjustment for age, gender, education, and occupation, the authors reported that “firm evidence remained for an association between an increase from seven or eight hours sleep and lower cognitive function for all tests, except memory, and between a decrease from six or eight hours sleep and poorer reasoning, vocabulary, and Mini-Mental State Examination score.” These adverse changes in duration were equivalent to a four- to seven-year increase in age.

African Americans with multiple sclerosis (MS) have lower vitamin D levels than their healthy counterparts, according to a study published in the May 24 Neurology. Researchers conducted a cross-sectional study of 339 African-American patients with MS and 342 without MS to determine if vitamin D levels were associated with MS disease severity. Between 71% and 77% of all participants were vitamin D–deficient and 93% to 94% were vitamin D–insufficient, the authors reported. Overall, vitamin D levels were lower in patients with MS, but this was due to differences in climate and geography and did not have an impact on disease severity. “These results are consistent with observations in other populations that lower [vitamin D level] is associated with having MS,” the investigators concluded, “but also highlight the importance of climate and ancestry in determining vitamin D status.”

Protein-based human-induced pluripotent stem cells (hiPSCs) and those derived from human embryonic stem cells (hESCs) may be effective in the treatment of Parkinson’s disease, according to a study in the May 16 Journal of Clinical Investigation. Results showed that neuronal precursors cells derived from hESCs and protein-based hiPSCs reversed disease when transplanted into the brains of rats modeling Parkinson’s disease. The researchers attempted to use neuronal cells derived from virus-based hiPSCs but were unable to do so because these virus-based cells exhibited apoptotic cell death. “[hiPSCs] are a potentially unlimited source of patient-specific cells for transplantation…. These data support the clinical potential of protein-based hiPSCs for personalized cell therapy of Parkinson’s disease,” the investigators concluded.

Women may have a greater risk than men for adverse events following certain stroke prevention procedures, as reported in the May 6 online Lancet Neurology. A total of 2,502 patients with symptomatic and asymptomatic stenosis were randomized to undergo carotid endarterectomy or carotid artery stenting. The rates of periprocedural stroke, myocardial infarction, and death were similar in men who underwent endarterectomy (4.9%) and stenting (4.3%). In women, however, a significant difference in rates of adverse events was observed—3.8% for endarterectomy versus 6.8% for stenting. “Periprocedural risk of events seems to be higher in women who have carotid artery stenting than those who have carotid endarterectomy, whereas there is little difference in men,” the authors concluded. “Additional data are needed to confirm whether this differential risk should be taken into account in decisions for treatment of carotid disease in women.”

About 14% of ischemic strokes presented at emergency departments are wake-up strokes, researchers reported in the May 10 Neurology. Wake-up strokes, according to the authors, cannot be distinguished from other types of stroke based on clinical features or outcome, making them difficult to treat with effective clot-busting therapies. The researchers analyzed data from patients presenting at emergency departments with ischemic stroke; they identified 1,854 ischemic stroke cases, 273 of which were wake-up strokes. “There were no differences between wake-up strokes and all other strokes with regard to clinical features or outcomes except for minor differences in age and baseline retrospective NIH Stroke Scale score,” the authors reported. “Of the wake-up strokes, at least 98 (35.9%) would have been eligible for thrombolysis if arrival time were not a factor.”

The annual rate of coronary artery bypass graft surgeries decreased 30% between 2001 and 2008, while rates of other percutaneous coronary interventions remained stable, according to an examination of national trends published in the May 4 JAMA. Investigators conducted a serial cross-sectional study to examine time trends of patients undergoing revascularization procedures, and determined that the annual surgery rate decreased from 1,742 to 1,081 per million adults in 2008. “Between 2001 and 2008, the number of hospitals … providing [coronary artery bypass graft surgery] increased by 12%, and the number of [percutaneous coronary interventions] hospitals increased by 26%,” the authors reported. They noted that new revascularization technologies, new clinical evidence from trials, and updated clinical guidelines may have affected the volume and distribution of coronary revascularizations.

Patients with traumatic brain injury (TBI) and refractory intracranial hypertension may benefit from decompressive craniectomy, but they may also experience unfavorable outcomes, according to a study in the April 21 New England Journal of Medicine. Researchers randomly assigned 155 adults with TBI and intracranial hypertension to undergo either bifrontotemporoparietal decompressive craniectomy or standard care. The results revealed that the standard-care group had higher levels of intracranial pressure and longer stays in the intensive care unit. “However, patients undergoing craniectomy had worse scores on the Extended Glasgow Outcome Scale than those receiving standard care,” the authors noted. Patients with craniectomy were also more than twice as likely to experience an unfavorable outcome, including death, vegetative state, or severe disability.

—Ariel Jones

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