New and Noteworthy Information—May 2015
Chronic disease burden increases the risk of mild cognitive impairment (MCI), but certain lifestyle factors reduce the risk of MCI in people ages 85 and older, according to a study published online ahead of print April 8 in Neurology. Participants in the population-based prospective study were evaluated at baseline and at 15 monthly intervals to determine incident MCI. At baseline, lifestyle factors in midlife and late life were assessed, and vascular and comorbid conditions were abstracted from participants’ medical records. The risk of MCI was increased for participants with APOE ε4 allele or current depressive symptoms. The risk of MCI was reduced for participants who reported engagement in artistic, craft, and social activities in both midlife and late life, and those who reported the use of a computer in late life.
A new blood test may identify biomarkers for Parkinson’s disease more accurately than before, according to a study published online ahead of print March 18 in Movement Disorders. Researchers used a digital gene expression platform to quantify 175 mRNA markers with low coefficients of variation. They compared whole-blood transcript levels in mouse models overexpressing wild-type LRRK2, overexpressing G2019S LRRK2, lacking LRRK2, and wild-type controls. The investigators then studied a cohort of 34 symptomatic patients with Parkinson’s disease and 32 asymptomatic controls. The expression profiles distinguished the four mouse groups with different genetic backgrounds. Significant differences in blood transcript levels were found between individuals differing in LRRK2 genotype and between patients with Parkinson’s disease and controls. Thus, whole-blood mRNA signatures may correlate with LRRK2 genotype and Parkinson’s disease state.
There is a relationship between Alzheimer’s disease-related white matter alterations and impaired cognitive-motor control, according to a study published January 1 in Journal of Alzheimer’s Disease. Using diffusion-weighted MRI, researchers examined changes in white matter integrity associated with normal aging and increased Alzheimer’s disease risk, and assessed the relationship between these white matter alterations and cognitive-motor performance. The investigators found significant age-related declines in white matter integrity, which were more widespread in patients at high risk of Alzheimer’s disease, compared with those at low risk. Furthermore, an analysis of mean diffusivity measures within isolated white matter clusters revealed a stepwise decline in white matter integrity across young, low Alzheimer’s disease risk, and high Alzheimer’s disease risk groups. Investigators also observed that lower white matter integrity was associated with poorer cognitive-motor performance.
Researchers have developed mild cognitive impairment (MCI) risk scores using variables that are easily assessable in the clinical setting and that may be useful in routine patient care, according to a study published April 7 in Neurology. Investigators randomly selected people between ages 70 and 89 on October 1, 2004, for a population-based sample in a longitudinal cohort study. At baseline and subsequent visits, participants were evaluated for demographic, clinical, and neuropsychologic measures and were classified as cognitively normal, having MCI, or having dementia. Of 1,449 cognitively normal participants, 401 developed MCI. Both men and women in the highest versus lowest sex-specific quartiles of the augmented model’s risk scores had an approximately sevenfold higher risk of developing MCI. The presence of APOE ε4 carrier status improved the model.
The progression of dysfunctional tau protein may be the primary cause of cognitive decline and memory loss in Alzheimer’s disease, according to a study published online ahead of print March 23 in Brain. Researchers evaluated the correspondence of Thal amyloid phase to Braak tangle stage and ante mortem clinical characteristics in a large autopsy cohort. In the brain bank cohort of patients with a high likelihood of Alzheimer’s disease, samples with lower Thal amyloid phases were older at death, had a lower Braak tangle stage, and were less frequently APOE ε4 positive. Regression modeling in these samples with Alzheimer’s disease showed that Braak tangle stage, but not Thal amyloid phase, predicted age at onset, disease duration, and final Mini-Mental State Examination score.
A panel of blood biomarkers distinguishes accurately between patients with isolated concussion and uninjured individuals within the first eight hours after an accident, according to a study published online ahead of print in March 20 in Journal of Neurotrauma. Adult patients were enrolled in a study within 24 hours of concussion. Controls included uninjured people and patients with orthopedic injury. The investigators identified copeptin, galectin 3, matrix metalloproteinase 9, and occludin as biomarkers of concussion. A 3.4-fold decrease in plasma concentration of copeptin was found in patients with mild traumatic brain injury (mTBI) within eight hours after accident, compared with uninjured controls. Plasma levels of all biomarkers but copeptin increased by 3.6 to 4.5 times during the same time postinjury. The levels of at least two biomarkers were altered beyond their cutoff values in 90% of patients with mTBI.
