If you were to think of cognition as a linear continuum, you might imagine, at one end, someone with a perfect memory and highly functional think­ing and language skills. Next might come a person in their senior years who is experiencing some brain changes and thus finding it a bit harder to think of words, a bit more difficult to maintain attention, a bit more common to forget little things…but certainly no worse off than others in their age group. At the far end would be people with Alzheimer’s or other forms of demen­tia…but squeezed in between them and the healthy older adults with normal age-related memory problems would be a group falling under the category of Mild Cognitive Impairment (MCI):

Normal cognition ➧ Normal age-related forgetfulness ➧ MCI➧ Dementia

In other words, people with MCI have more serious cognitive deficits than most people their age, yet their issues are not so severe as to be labeled demen­tia or Alzheimer’s disease, nor do they affect the person’s everyday functioning.

Memory and More

In evaluations, people with MCI have a tougher time remembering details from a picture they’ve been shown, or recalling what words appeared in a paragraph of text they’ve read, than people without the condition. Yet memory is just one of several cognitive features affected by MCI. Others include visual-spa­tial awareness, language, and decision-making.

For example, someone with mild cognitive impairment might get lost while walking through their own workplace. They could have trouble following the plot line of a book they’re reading. They may begin missing social events purely because they forgot about them, or perhaps because they never managed to put them into their calendar. They may find it hard to follow a recipe or the setup instructions that come with a new product, despite a history of being good at such things. They may demonstrate poor judgment in driving or in managing the household finances.

Many people with MCI also undergo significant mood or personality changes. Whether caused by frustration and embarrassment or underlying brain changes, they may display irritability, aggressiveness, depression, anxi­ety, or a noticeable decline in interest in things they were, until recently, fully engaged with.

Cause of Mild Cognitive Impairment

Don’t assume that just because someone has MCI, they’re necessarily on the path to full-blown dementia. Only about a third of people with MCI fit that profile, some of whose illness may be labeled “MCI due to Alzheimer’s.” Another third of cases get better, while the remaining third stays the same without progressing.

MCI can come from any of several causes. There appears to be a connection between MCI and traumatic brain injury (TBI), as often seen in injured sol­diers and football players. Among an older group of veterans, a prior TBI was associated with a 60% increased risk of later developing MCI.

Sleep apnea, too, may play a role. In a study led by researchers at New York University, people with both MCI and sleep apnea had been diagnosed 10 years earlier than those without the condition. And, as with many conditions, lifestyle factors appear to affect the risk for MCI as well as its severity. Besides diet and exercise, MCI risk also appears affected by social engagement, participation in intellectually stimulating activities, air pollution, smoking, and even hearing and vision loss.

Some people with MCI appear to undergo changes to their brain sizes and structures that are similar to, but less pronounced than, those of people with Alzheimer’s or other forms of dementia. In particular, the hippocampus, some­times called the brain’s memory center, typically shrinks with age but especially so with MCI, though not to the extent seen with Alzheimer’s.

Testing for Mild Cognitive Impairment

If someone is alarmed by the amount of forgetfulness they’ve been experienc­ing and feels that something more serious than normal age-related cognitive decline is going on, the best advice is to open a discussion with their primary care physician. While most primary care doctors aren’t special­ists in cognitive issues, they can perform a basic evaluation to see if there’s reason for concern. The doc­tor will begin by gathering as much information as possible about your symptoms—when you first noticed a problem, what kinds of cognitive lapses you’ve been experiencing, and how they affect your daily activities. Often, the physician will seek the perspective of a close loved one to see if they have observed problems with deci­sion-making, planning, and remembering. The doctor will probably test your reflexes, eye movements, and balance to see how well your neurological system is functioning. Memory and thinking problems can sometimes be caused by medications, poor sleep, high blood pressure, infections, stress, depression, and several other health and lifestyle factors. Your doctor will explore such possible causes, sometimes using blood tests, to see if there’s an easily addressed explanation for your issues. If not, they will refer you to a psychologist, neu­rologist, or other specialist for more advanced testing.

Clinicians may use a brief mental-status test such as the Montreal Cogni­tive Assessment (MoCA), the Short Test of Mental Status, or the Mini Mental State Examination (MMSE). These quick exams, which take only about 10 minutes, can give the clinician a good sense of a person’s degree of impairment. Longer-form tests are also available, which can round out the clinician’s picture of your cognition and provide greater detail about your case.

Depending on the results of these tests, the specialist may also order a brain scan to make sure that your cognitive issues don’t stem from a tumor or brain injury.

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