Where Did I Put My Car Keys Again?

Dace L. Trence, MD, FACE

How often have you asked yourself or your family members this question, only to think “I am losing it?” As we get older, it’s normal for memory to be affected -- what is called short-term or recent memory, in particular, becomes less sharp, but it’s normal only to a degree.

Forgetfulness, confusion and difficulties with everyday tasks not only exact an emotional toll, but the physical toll can be very concerning as well when changes become progressive. They can completely change family dynamics and structure. A daughter becomes a caregiver for her father, a sister for her brother, a grandchild for their grandparent. Often, the experience is more than concerning and can be downright frightening to see the loss of capacity in a parent, a spouse, or a friend.

Lapses in memory every so often are a normal part of the aging process, not a warning sign of concerning mental deterioration or the onset of dementia...and certainly not a reason to panic. Occasionally forgetting where you left things you use regularly, such as glasses or keys, is normal. Momentarily forgetting names of friends or blocking one memory with a similar one, such as calling a sister by your daughter’s name, also is perfectly normal. Equally non-concerning is forgetting an appointment or walking into a room and forgetting why you entered. That happens to everyone.

When your memory loss begins to affect your ability to function, however, that is cause for concern.

The primary difference between age-related memory loss and dementia is that memory loss may be exasperating and outright frustrating at times, but it’s not disabling. The occasional memory lapse typically doesn’t affect day-to-day activities and your ability to do what you want to do. We can often laugh it off as a “senior moment” and go on with our activities and function very well.

Dementia, on the other hand, is marked by a persistent, disabling decline in two or more intellectual abilities such as memory, language, judgment and the ability to think things through. When memory loss becomes so frequent and severe that it disrupts your work, hobbies, social activities and family relationships, you may be experiencing the warning signs of Alzheimer’s disease or another disorder that causes or mimics dementia.

Dementia affects the way the brain normally functions, and the condition can affect memory, speech, even the ability to successfully complete daily activities such as dressing, bathing, or eating. It’s more likely to affect those with poorly controlled diabetes mellitus, high blood pressure, high cholesterol and heart disease, as these are risks for a specific type of memory loss and function called vascular dementia. This is a dementia that is related to multiple small strokes that damage brain tissue by preventing oxygen and necessary nutrients from reaching brain cells. High blood pressure is an especially important risk factor and a major contributor to these small strokes. But poorly controlled diabetes increasingly is being targeted on as a memory loss risk factor.

"The primary difference between age-related memory loss and dementia is that memory loss may be exasperating and outright frustrating at times, but it’s not disabling."

For two years, Harvard researchers tracked 40 people with type 2 diabetes mellitus – the type of diabetes in which one’s own insulin does not work as it should, compounded by a decreased production of insulin over time – as well as people without diabetes. Even in that relatively short amount of monitoring, there was a significant difference found in thinking and memory test results among the research participants.

At the start of the study, participants were given tests for thinking and memory, had MRI scans to look at brain volume and blood flow, and underwent additional blood tests to measure blood sugar levels and overall blood sugar control as well as blood tests to measure general inflammation.

After two years, the study participants were tested again. Those with diabetes showed marked decreases in blood flow regulation in the brain. They had lower scores on several tests of memory and thinking skills and found it harder to carry out daily tasks such as bathing and cooking.

As an example, on a test of learning and memory, the scores of the people with diabetes decreased by 12 percent, from 46 points to 41 points, while the scores of those without diabetes stayed the same at 55 points. The researchers did note that additional studies involving more people and conducted for a longer time period were needed to better understand the relationship and timing with blood flow regulation and changes in thinking and memory skills before definitive conclusions could be made.

Researchers from Germany have reported that even individuals without diabetes who have high blood sugar levels may be at risk for impaired memory skills. They report on 143 people with an average age of 63 who were free of diabetes or pre-diabetes (impaired glucose intolerance). Those who were overweight, drank a significant amount of alcohol (defined as more than 3.5 servings of alcohol per day), smokers, and those who already had memory and thinking impairments were excluded from the study.

Study participants underwent blood sugar testing and were asked to complete memory tests. One of the tests required participants to recall a list of 15 words 30 minutes after hearing them. Additionally, brain scans of the participants' brains were done to measure the size of the hippocampus – a region of the brain linked to memory.

Results showed that participants who had lower blood sugar levels obtained higher scores on the memory tests compared with those who had higher blood sugar levels. In the word recall test, the researchers found that remembering fewer words was linked to higher blood sugar levels, reporting that an increase of about 1.4 percent of a blood sugar marker called HbA1c correlated with recalling two fewer words.

Although diabetes is highlighted here as a risk for memory loss and dementia, other reasons for memory loss should be checked by your healthcare team, such as thyroid disease and possible side-effects of medications. But for those with diabetes, the risk of dementia can be mitigated by keeping those blood sugars, blood pressure and cholesterol under control.