When a Neurologist's Memory Starts Failing
A high power MD from a preeminent medical center, a 56-year-old Neurologist came to my office because he felt
his memory was failing. He forgot clients' names in mid-conversation and
was losing track of important details at work. Although he seemed
completely fine on my initial neurological examination, he underwent a
several hours-long neurocognitive evaluation, the best way to evaluate
cognition in high functioning people.
In
this test, we took his brain on a demanding, cognitive test drive to
assess his verbal, visual, and working memory, his language, his
abstract skills, his processing speed, and many other aspects of his
intellect. We discovered that although he was smarter than most people
his age, scoring at the 98th percentile, he performed poorly on some
tests of auditory memory, confirming his own suspicions.
Because he was
still functioning extremely well, I diagnosed him as having cognitive
impairment -- without specifying the cause -- and put him on medications
to help his memory. Over three years of annual testing however, he
continued to decline on specific memory tests.
This
concerned us both and my patient desired diagnostic clarification.
Cerebrospinal fluid analysis revealed tell-tale amyloid plaques and
neurofibrillary tangles, the fingerprints of Alzheimer's disease.
So, at
the age of 57, my patient now had biological evidence of Alzheimer's
disease, although he continued functioning well at his medical office and few
people suspected problems.
Even
I, his neurologist, with 25 years of experience in cognitive neurology,
could not tell from repeated conversations with him over three years
that he had any real memory issues.
So, what was my verdict? Did he or didn't he have Alzheimer's disease? My answer has gotten more complicated over the years.
My
patient was holding his own in life thanks to his tremendously
versatile brain, which continued to be mostly resilient to the
Alzheimer's disease pathology. I told him he had mostly asymptomatic
Alzheimer's disease. However, the lay narrative of Alzheimer's disease
is unvarying and grim, and I worried that my patient would succumb to
its nightmarish predictions.
I
needed him to understand that an individualized approach is key to
diagnosing, treating, and living fully with Alzheimer's disease. For
example, you could sit through dinner with another patient of mine,
diagnosed with near identical spinal fluid analysis over a decade ago,
discuss Yeats, Sinatra, yesterday's news and today's stocks, and leave
thinking, "He has Alzheimer's? No way!"
This
disconnect between pathology and clinical symptoms is a confusing
conundrum not only for patients like this Neurologist, but also their physicians like myself. In a recent study
of over 5,000 American adults between age 55 and 89 years published in
JAMA Neurology, there were significantly more people with biologically
defined Alzheimer's, with plaques and tangles visualized on brain-tracer
scans, than there were people with clinical Alzheimer's disease,
exhibiting symptoms.
Among
85-year-olds, for every three people with the pathology, only one person
had symptoms. In other words, most men and women with biologically defined Alzheimer's had no symptoms. And with 40% of
80-plus-year-olds having plaques without symptoms, yet 25-50% of elders
complaining of memory loss, determining what's normal and what's
Alzheimer's is a difficult feat.
For
one thing, the clinical diagnosis of Alzheimer's disease hinges on
functioning, which depends on performance expectations, varying from a
seated Supreme Court Justice to a retired postal employee. The
expectation each of us has of our memory and cognitive function is based
on our specific set of circumstances, so context cannot be ignored when
evaluating cognitive deficits.
To
confound matters, even the assumption that plaques and tangles cause
the symptoms of Alzheimer's is now being questioned. Amyloid plaques are
starch-like deposits found outside nerve cells, and neurofibrillary
tangles are hair-like clumps found inside nerve cells, and the
traditional thinking was that these deposits led to nerve cell death and
ultimately, symptoms of Alzheimer's.
It is becoming clear that the association between such pathology and symptoms vary from person to person. Many factors
affect the progression to Alzheimer's, in addition to genetics,
including cognitive and physiological factors, and the areas of the
brain that are affected. These factors are so influential that even in
identical twins, symptom onset of Alzheimer's disease can vary by as
many as 18 years.
Furthermore, as I detail in a New England Journal of Medicine article,
professionals, including physicians, can function competently even with
clinical symptoms of Alzheimer's disease.
Just as each brain is unique,
so is the disease progression and continued functioning of people with
Alzheimer's. Variability in the disease's course is the norm, with some
people staying stable for years, even without treatment. Yet, while we
know that two people with the same type of kidney disease or breast
cancer progress differently, with Alzheimer's disease the overwhelming
belief is that everyone ends up in a wheelchair, unable to recognize
family and themselves.. While this is true in some, it is not the case
for all.
Even as some drug companies virtually abandon Alzheimer's disease therapeutic development,
with failures and costs mounting, I believe the problem lies in too
broad a definition of the term "Alzheimer's disease." What we need is
better definition of different types of Alzheimer's as well as different
types of patients to help develop drugs targeted for subgroups, to
practice a more precise medicine.
A 57-year-old retired teacher with Alzheimer's disease pathology,
overweight, sedentary, with emphysema from smoking, strokes and heart
disease will progress very differently from my tennis-playing,
67-year-old attorney patient without any heart problems -- even if they
had the same amount of plaques and tangles.
Both
for instituting proper policies and for finding cures for various
subtypes of Alzheimer's disease, the need is to align the grim and
unvarying societal narrative with the nuanced and complex scientific
narrative. Bridging this divide is crucial for destigmatizing the
disease and for providing the type of tailored treatment that will bring
success in treating those with clinical symptoms of the illness.
My
patient satisfies biological criteria for Alzheimer's, and by some
measures, clinical criteria as well. The truth is, however, that had he
not had an extensive cognitive evaluation, routine testing would have
found him — and continues to find him — cognitively normal.
But
this man is now afflicted with what another patient of mine calls the
"The Doubting Disease," the psychological consequence of any hint of an
Alzheimer's diagnosis. Is his daily forgetting normal or is he
experiencing symptoms of Alzheimer's? He is constantly doubting himself.
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Physicians
should not dismiss memory and cognitive complaints from
high-functioning patients who appear normal. Proactive treatment is
best, before symptoms appear. Decisions about further testing and
treatment should be made collaboratively. Patients with a diagnosis
must be educated about the vast spectrum that is Alzheimer's and illness
variability, as well as proven methods to slow progression, including
diet, exercise, and sleep.
As for
my patient, he and I have agreed that he will be treated, aiming to
bolster his cognition, and reduce risk factors of the disease, with a
program tailored for him -- for his own private Alzheimer's disease. He
continues working as a successful neurologist, keeping his diagnosis a top
secret.
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