Memory Loss — Full Text

Everyone is afraid of getting Alzheimer’s Disease.  So it’s common for some people, especially as they age, to worry if they think they have memory problems.  Most are fine. 

Basically, we try to distinguish among the following:

  1. No true memory problems
  2. Memory problems due to a medical condition
  3. Mild memory loss (called Mild Cognitive Impairment or MCI)
  4. Dementia  (profound memory problems that will progress)

Let’s begin with a big dose of Reassurance — people with Dementia rarely seek care on their own, because they don’t realize or remember what they’re forgetting.  Families and Friends bring them in, and are key to providing the details, including behavior changes.  If a patient themselves remembers how long they’ve had memory problems, their memory is fine.  Some are just nervous, what we call “worried-well,” others may be suffering from true Anxiety or Depression.

Abrupt memory loss and confusion that suddenly just began is alarming; the term is “Delirium“.  It requires a rapid diagnosis, best achieved in the Emergency Room.  This is due to a medical illness, which might be life-threatening.  A key question involves orientation to time: asking what’s the date, day of week, month, & especially year. 

Anybody might miss the date by a day or two, or might say “Thursday” when it’s really Friday.  But everybody should know the month, & even the most uneducated know the year.  I’ve had two patients who knew it all except the year, and both had serious brain diseases.  Delirium has countless causes, which is another topic (click the link for examples).

The diagnosis “Mild Cognitive Impairment” (MCI) is vague.  It occurs with age (usually 70s).  We use the term for patients still able to function in society & life.  Some will go on to get Dementia, others never will.  Such patients are often aware of & concerned about their memory loss.

So to begin, let’s say we see a patient, maybe with their family, with the concern of forgetting things.  They know day, date, etc., so it’s not Delirium.  At the first visit, we try to get a sense of the degree to which this happens, how recent it’s occurred, and especially if it’s progressively getting worse.  We seek examples of what they’ve forgotten.

  • Does it interfere with normal activities and job?
  • Is it dangerous?  Like forgetting food cooking on stove, losing keys, getting lost, serious financial errors.
  • Do they forget things that you [the reader] & I would never forget, no matter how preoccupied (like names of major people in their lives, like children, since everyone forgets people’s names now & then)?
  • Have they had personality changes during the same time frame?

On the first visit, we obtain a general medical & psychiatric history, and perform a general physical exam, especially a decent neurological exam.  Sometimes this takes two visits.  Key questions to ask about, especially if they match up with the time that memory loss began, include:

  • Head trauma — must get a brain CT Scan to rule out a blood clot
  • Some Medications  —  try discontinuing them if at all possible (esp. benzodiazepines for insomnia or anxiety: lorazepam, diazepam, alprazolam, zolpidem, etc.)
  • Drugs & Alcohol  —  same as above, though often harder to achieve
  • Newly-Diagnosed Medical Diseases  —  memory loss can occur from kidney failure, heart attack, stroke, uncontrolled diabetes, etc. etc.

The neurological exam should specifically look for abnormalities on just one side of the body (especially the “cranial nerves” for eyes & face), which could suggest Stroke or Tumor.  We also seek signs of Parkinson’s Disease: hand tremor when it’s resting, expressionless face, walk with a shuffle, jerkiness as I gently wiggle their relaxed arm (“cogwheeling”). These can cause memory problems of varying degrees.

There are several memory and mental status exams that all seem about the same, able to identify around 80-85% of people with dementia, less accurate for mild cases.  They usually include two key components: 1) remembering 3 words at 5 minutes later (after practicing the words a couple of times); and 2) drawing a clock with a certain time.  But the one I like best is the “Animal Fluency Test”:  have the patient name as many animals as possible in 1 minute.  Naming 18 or more is normal, fewer than 12 is Dementia of one sort or another, in between is uncertain (<15 may suggest Alzheimer’s).

Another useful strategy questions informants, i.e. friends & family, using the AD8 Dementia Screening Interview.  It and other tools can be accessed through the Alzheimer’s Association at http://www.alz.org.

If the above memory testing is normal, we reassure the patient, though if they seem unconvinced, we might order basic laboratory tests [see below].  If those are normal, and the patient remains worried on follow-up, we explore Anxiety & Depression if we haven’t yet.

Sleep Deprivation can cause functional memory loss.  I made a “brilliant” diagnosis once, years ago; it took me less than 10 minutes; quotes used because a  major medical center’s memory clinic missed it.  Click for a link to an (in my mind) unethical anecdote.

Laboratory Tests

Once we identify any degree of memory problem, the first step is to rule out treatable causes due to medical conditions.  Assuming that both general & neurological exams are normal, we order a few basic lab tests:

However, we should note that the vast majority of laboratory tests ordered for memory loss come out normal.  So on the one hand, cost-effectiveness could be considered worthless.  That of course gets weighed against the horrors of failing to detect a reversible cause.  Clink link for a case of Missed Diagnosis.

Imaging (X-Rays)

The American Academy of Neurology recommends either a brain CT scan (without contrast dye) or MRI when first working up true memory loss, looking for blood clots (subdural hematomas), cancers, or the rare Hydrocephalus (too much fluid on the brain).  The CT can detect abnormalities large enough to diagnose Dementia, but the MRI is more useful for those with milder memory problems (Mild Cognitive Impairment).  It can identify temporal lobe atrophy and other patterns that may predict a likelihood of eventually developing Dementia.

Other experts only order these images in special cases: dementia getting worse rapidly, or patients <60 y.o.  Certainly, anyone with specific neurologic abnormalities requires a contrast-enhanced MRI for strokes, infections, or tumors, and those with history of head trauma should get non-contrast CTs for blood clots in the brain (Subdural Hematomas).

For competent, functional patients whose memory testing is just a bit low enough to consider Mild Cognitive Impairment, we don’t order an MRI without a discussion.  First, we reassure them they do not have Alzheimer’s.  We say their condition may or may not get worse.  It’s important to ask if they want to know right now whether they’re high risk of developing true Dementia, or simply prefer to wait and see what happens in life over the next few years.

Referrals

I tend to refer all my patients with significant memory problems to Neurology.  Since Dementia from Alzheimer’s Disease, and other degenerative neurological conditions like Lewy-body or Fronto-Temporal Dementia, are irreversible with poor prognoses and major implications, I like a specialist to confirm the diagnosis (See Link for definitions).

Small Strokes can cause Dementia (called โ€œVascularโ€, or โ€œMulti-infarctโ€, Dementia), without any other symptoms.  It’s more common with very advanced age, especially if there are other stroke risks like hypertension, diabetes, smoking, high cholesterol, etc.  The only treatment is what we would do anyway for those conditions.  Medications used for Alzheimer’s don’t help, but frankly, those drugs hardly do much for anything anyway.

The need for precise diagnosis of Dementia will change if more effective treatment ever appears.  In terms of non-drug treatment, it’s essentially the same for all kinds — kindness, exercise, activity, and prioritizing safety.

“Memory Loss” With Completely Normal Exam and Tests

Most patients are reassured that their evaluation is normal, especially whatever memory tests were done.  Those who remain unconvinced usually suffer from Anxiety or Depression.  We often obtain the basic laboratory tests above, since they may be part of diagnosing new mood disorders.  We’d only order images if the mood or personality changes were significant, not for perceived memory loss with normal findings (the “worried-well”).

See also Memory Loss for the clinicianโ€™s condensed thought-process when face-to-face with a patient.

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