Neuroimaging categorizes 4 depression subtypes

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.

We know that people with depression tend to focus on, and remember, negative memories rather than positive. Interestingly, it’s not simply an emotion effect. People with depression, and even those at risk of depression (including those who have had depression), tend to have trouble remembering specific autobiographical memories. That is, memories of events that happened to them at a specific place and time (as opposed to those generalized event memories we construct from similar events, such as the ‘going to the dentist’ memory).

I have reported previously on research suggesting that rapamycin, a bacterial product first isolated from soil on Easter Island and used to help transplant patients prevent organ rejection, might improve learning and memory. Following on from this research, a new mouse study has extended these findings by adding rapamycin to the diet of healthy mice throughout their life span. Excitingly, it found that cognition was improved in young mice, and abolished normal cognitive decline in older mice.

The study involved 104 healthy older adults (average age 87) participating in the Oregon Brain Aging Study. Analysis of the nutrient biomarkers in their blood revealed that those with diets high in omega 3 fatty acids and in vitamins C, D, E and the B vitamins had higher scores on cognitive tests than people with diets low in those nutrients, while those with diets high in trans fats were more likely to score more poorly on cognitive tests.

In the last five years, three studies have linked lower neighborhood socioeconomic status to lower cognitive function in older adults. Neighborhood has also been linked to self-rated health, cardiovascular disease, and mortality. Such links between health and neighborhood may come about through exposure to pollutants or other environmental stressors, access to alcohol and cigarettes, barriers to physical activity, reduced social support, and reduced access to good health and social services.

Following several recent studies pointing to the negative effect of air pollution on children’s cognitive performance (see this April 2010 news report and this May 2011 report), a study of public schools in Michigan has found that 62.5% of the 3660 schools in the state are located in areas with high levels of industrial pollution, and those in areas with the highest industrial air pollution levels had the lo

Amnestic mild cognitive impairment often leads to Alzheimer's disease, but what predicts aMCI? A study involving 94 older adults has revealed that lower performance on tests measuring learning, in conjunction with either slower visuomotor processing speed or depressive symptoms, predicted the development of aMCI a year later with an accuracy of 80-100%. It is worth emphasizing that poor learning alone was not predictive in that time-frame, although one learning measure was predictive of aMCI two years later.

A review of 35 studies published between 1991 and 2007 has found that depression does not always lead to cognitive impairment. Part of the variability in findings may be due to inconsistent measurement and diagnosis of depression. Processing speed was found to be the cognitive function most consistently affected by depression. Processing speed deficits can be helped by decreasing the amount of information to process at one time.

Obstructive sleep apnea (OSA) occurs when a person's breathing is interrupted during sleep.

People with OSA are known to suffer memory problems and also have higher rates of depression.

A new study connects the two by finding that people with untreated OSA had problems recalling specific details about their lives. Previous research has established that persistent depression is associated with overly general autobiographical memories, where people don't remember many specific details of life events.