Long term exposure to pesticides linked to cognitive decline

Previous research has pointed to an association between not having teeth and a higher risk of cognitive decline and dementia. One reason might have to do with inflammation — inflammation is a well-established risk factor, and at least one study has linked gum disease to a higher dementia risk. Or it might have to do with the simple mechanical act of chewing, reducing blood flow to the brain. A new study has directly investigated chewing ability in older adults.

Providing some support for the finding I recently reported — that problems with semantic knowledge in those with mild cognitive impairment (MCI) and Alzheimer’s might be rooted in an inability to inhibit immediate perceptual information in favor of conceptual information — a small study has found that executive function (and inhibitory control in particular) is impaired in far more of those with MCI than was previously thought.

Sometime ago, I reported on a study showing that older adults could improve their memory for a future task (remembering to regularly test their blood sugar) by picturing themselves going through the process. Imagination has been shown to be a useful strategy in improving memory (and also motor skills). A new study extends and confirms previous findings, by testing free recall and comparing self-imagination to more traditional strategies.

Problems with myelin — demyelination (seen most dramatically in MS, but also in other forms of neurodegeneration, including normal aging and depression); failure to develop sufficient myelin (in children and adolescents) — are increasingly being implicated in a wide range of disorders. A new animal study adds to that evidence by showing that social isolation brings about both depression and loss of myelin.

A small Swedish brain imaging study adds to the evidence for the cognitive benefits of learning a new language by investigating the brain changes in students undergoing a highly intensive language course.

Green tea is thought to have wide-ranging health benefits, especially in the prevention of cardiovascular disease, inflammatory diseases, and diabetes. These are all implicated in the development of age-related cognitive impairment, so it’s no surprise that regular drinking of green tea has been suggested as one way to help protect against age-related cognitive decline and dementia. A new mouse study adds to that evidence by showing how a particular compound in green tea promotes neurogenesis.

Caffeine has been associated with a lower of developing Alzheimer's disease in some recent studies. A recent human study suggested that the reason lies in its effect on proteins involved in inflammation. A new mouse study provides more support for this idea.

A study using data from the Lothian Birth Cohort (people born in Scotland in 1936) has analyzed brain scans of 638 participants when they were 73 years old. Comparing this data with participants’ earlier reports of their exercise and leisure activities at age 70, it was found that those who reported higher levels of regular physical activity showed significantly less brain atrophy than those who did minimal exercise. Participation in social and mentally stimulating activities, on the other hand, wasn’t associated with differences in brain atrophy.

HIV-associated dementia occurs in around 30% of untreated HIV-positive patients. Surprisingly, it also is occasionally found in some patients (2-3%) who are being successfully treated for HIV (and show no signs of AIDS).

A new study may have the answer for this mystery, and suggest a solution. Moreover, the answer may have general implications for those experiencing cognitive decline in old age.

Here’s an exciting little study, implying as it does that one particular aspect of information processing underlies much of the cognitive decline in older adults, and that this can be improved through training. No, it’s not our usual suspect, working memory, it’s something far less obvious: temporal processing.