Neurology

Memory-related brain network shrinks with aging
Brain regions associated with memory shrink as adults age, and this size decrease is more pronounced in those who go on to develop neurodegenerative disease, reports a new study published Sept. 18 in the Journal of Neuroscience (Vol. 33:38). The volume reduction is linked with an overall decline in cognitive ability and with increased genetic risk for Alzheimer's disease, the authors say. MedicalXpress

Alzheimer's progression tracked prior to dementia
The classification system divides preclinical Alzheimer’s into three stages:

•Stage 1: Levels of amyloid beta, a protein fragment produced by the brain, begin to fall in the spinal fluid. This indicates that the substance is beginning to form plaques in the brain.

•Stage 2: Levels of tau protein start to rise in the spinal fluid, indicating that brain cells are beginning to die. Amyloid beta levels are still abnormal and may continue to fall.

•Stage 3: In the presence of abnormal amyloid and tau biomarker levels, subtle cognitive changes can be detected by neuropsychological testing. By themselves, these changes cannot establish a clinical diagnosis of dementia. WashU

Where does dizziness come from?
Johns Hopkins researchers say they have pinpointed a site in a highly developed area of the human brain that plays an important role in the subconscious recognition of which way is straight up and which way is down. The finding, described online in the journal Cerebral Cortex, may help account for some causes of spatial disorientation and dizziness, and offer targets for treating the feelings of unsteadiness and "floating" people experience when the brain fails to properly integrate input from the body's senses. Eurekalert!

Neurological researchers find fat may be linked to memory loss
Although there are several risk factors of dementia, abnormal fat metabolism has been known to pose a risk for memory and learning. People with high amounts of abdominal fat in their middle age are 3.6 times as likely to develop memory loss and dementia later in their life. Rush University Medical Center

Study shows how infections in newborns are linked to later behavior problems
Researchers exploring the link between newborn infections and later behavior and movement problems have found that inflammation in the brain keeps cells from accessing iron that they need to perform a critical role in brain development.

Specific cells in the brain need iron to produce the white matter that ensures efficient communication among cells in the central nervous system. White matter refers to white-colored bundles of myelin, a protective coating on the axons that project from the main body of a brain cell. Eurekalert!

Researchers find that 'peanut butter' test can help diagnose Alzheimer's disease
The scientists found that patients in the early stages of Alzheimer's disease had a dramatic difference in detecting odor between the left and right nostril—the left nostril was impaired and did not detect the smell until it was an average of 10 centimeters closer to the nose than the right nostril had made the detection in patients with Alzheimer's disease. This was not the case in patients with other kinds of dementia; instead, these patients had either no differences in odor detection between nostrils or the right nostril was worse at detecting odor than the left one. MedicalXpress

Another Study Slams Vascular Theory of MS (CME/CE)
An assessor-blinded analysis of catheter venography images in 65 patients with MS, 46 of their siblings, and 32 unrelated healthy individuals identified just one person in each group as meeting criteria for "chronic cerebrospinal venous insufficiency" (CCSVI), according to Anthony L. Traboulsee, MD, of the University of British Columbia in Vancouver, and colleagues. Using broader definitions of cerebrospinal venous narrowing or stenosis, most people in each group qualified, whether imaged with catheter venography or ultrasound, the researchers reported online in The Lancet. MedPage Today