From the Editor
Is the incidence of dementia falling?
What makes a good clinician?
This week, I’ve selected two Readings. We open with a NEJM paper suggesting a big trend: a decline in the incidence of dementia. That paper obviously has major implications for public policy. We then move on to a big and eloquent essay on a famous doctor, Oliver Sacks.
There isn’t much connecting these selections – except that both were suggested by readers, and they both raise big questions.
“Incidence of Dementia over Three Decades in the Framingham Heart Study”
Claudia Satizabal et al., The New England Journal of Medicine, 11 February 2016
Dementia is the leading cause of dependence and disability in the elderly population worldwide. As the average life expectancy increases, the prevalence of dementia and associated monetary costs are expected to increase exponentially. A few studies have suggested that the age-specific incidence of dementia (i.e., the risk of dementia at any specific age) might be decreasing, but these studies either have shown a trend that failed to reach significance or have relied on comparisons of prevalence data that were ascertained at multiple time points. One study showed no decline in incidence. Temporal trends are best derived through continuous monitoring for new cases in a representative community-based sample over an extended observation period, with the use of consistent diagnostic criteria; however, such data from published studies are limited. We estimated temporal trends in the incidence of dementia over three decades among participants in the Framingham Heart Study.
So opens a paper from The New England Journal of Medicine that seeks to answer a simple question: in an aging society, will we have more demented people? The paper has gathered much attention in part because of its big finding: incidence has declined by 20% every decade over the past 30 years. (!)
But if much media has covered the paper, the reportage has often been limited to just this one finding. The paper itself is nuanced and detailed, and worth a fuller consideration, and draws from one of the best known longitudinal studies of all time: the Framingham Heart Study.
Here’s what they did:
· In 1971, 5,214 offspring of the original 1948 Framingham cohort and their spouses were enrolled, joining the original subjects.
· Cognitive status was monitored, including with the Mini-Mental State Examination (MMSE) – since 1981 for the original participants, and with their offspring since 1991. Other testing has been added, including a neuropsychological test (in 1999, administered roughly every five years).
· A dementia review panel, which included a neurologist and a neuropsychologist, reviewed every case of possible cognitive decline and dementia.
· The authors also considered educational achievement (high school diploma vs. no high school) and a variety of cardiovascular risk factors.
· Different statistical analyses were employed. Data was divided by time, with four non-overlaping “epoch periods,” from 1977 to 2008 of roughly 5 years each.
Here’s what they found:
· 5,205 participants were involved in total, with 2,000 providing full data across all four epochs. The age range was 60 to 101.
· There were 371 cases of dementia.
· Over time, trends became clear, including a drop in the incidence of dementia. (!) Here’s a quick summary of the main finding by USA Today. (Yes, I’m using USA Today as source… everything is possible.)
· The mean age of onset of dementia changed from 80 (first epoch) to 85 (fourth epoch). (!)
· Fewer people had vascular dementia (but not fewer people with Alzheimer), suggesting that stroke risk factors were better controlled. The authors found an increasing benefit from the use of antihypertensive medications, and a decreasing effect of cardiovascular events on the risk for dementia.
· Education seemed to be protective. The study showed that the decline in the incidence of dementia was limited to those who finished high school, with a decline in risk per decade of 23% (HR, 0.77). (!)
The authors conclude:
Results from the Framingham Heart Study showed a progressive decline in the incidence of dementia over three decades. This temporal trend and a parallel improvement in cardiovascular health over time were both observed only in the cohort of persons who had at least a high school diploma. Rising educational levels might have contributed to the 5-year delay we observed in the mean age at onset of clinical dementia.
A few thoughts:
1. This is a big paper in a big journal – The New England Journal of Medicine, no less.
2. The findings are good news. Let’s be clear: dementia remains too common and, in human terms, it is often tragic and difficult for patients and their families. Still, at least with the Framingham cohorts, dementia became less common as a percentage of participants.
3. Of course, we can ask: how excited should we be? Are the results generalizable? The accompanying editorial raises this question. Further study in the area will help better understand this trend, but it should be pointed out that the data is drawn from the Framingham Heart Study, and thus must be taken seriously.
4. And looking ahead, we can ask: is the trend likely to continue? With high rates of obesity, it’s possible that tomorrow’s elderly are less ‘brain healthy’ than today’s seniors. If this study is any indication, the incidence of demented people may be dropping despite some public health challenges (like high rates of obesity across the west).
“How Oliver Sacks put a human face on the science of the mind”
Norman Doidge, The Globe and Mail, 10 February 2016
In February, 2015, neurologist Oliver Sacks – arguably the world’s best-known brain doctor and the greatest physician writer in English, wrote an article in The New York Times called My Own Life, announcing that ‘my luck has run out.’
Dr. Sacks, 81 years old, still wildly productive, clear-headed, feeling robust, and swimming a mile a day, had just found out he had multiple metastases, from an ocular cancer that had been treated nine years before. One-third of his liver was filled with cancer.
“No sooner had he shared his ill fortune than did he begin to write of his gratitude for the years he had been granted since his original diagnosis, and his overall feeling of gratitude for having lived as ‘a sentient being, a thinking animal, on this beautiful planet …’
So begins Norman Doidge’s long essay describing the life and death of neurologist Oliver Sacks. Many of you will have already read this essay – this selection is from one of the country’s most prominent newspapers. If you haven’t read Doidge’s essay, it’s worth reading; if you have, I invite you to read it again.
Like many biographical essays, this one touches on the Sacks’ birth and childhood. It details his education. And it is rich in detail – Sacks liked radishes; he had an eclectic circle of friends, that included Nobel laureates and his cleaning lady; he was a doctor, but also a patient (of psychoanalysis). The essay considers his sexuality and faith, or lack thereof. The essay works in part because the subject is so entertaining – a motorcycle driving, Canadian Air Forces reject turned neurologist, then celebrated author.
Doidge, a psychoanalyst and writer, has produced an interesting if unusual read: start with the fact that the essay stretches to almost 9,000 words (many fold longer than the typical 700 word essay that populate newspapers). Doidge begins with Sacks’ end – the cancer that claims his life. Doidge’s review of his life is anchored by Sack’s writing: his books and essays.
The focus on writing is fitting. After all, Sacks is primary known as an author – and what an author. His most famous book was turned into a Hollywood movie; his most popular book was a bestseller, and became an opera. But, oddly, his famous books are about patients with neurological disorders. The Man Who Mistook His Wife for a Hat is a handful of neurology case studies. It’s not exactly the sort of material bestsellers typically draw from.
Doidge puts Sacks writing in a larger and historic perspective:
It may sound a strange claim, but the detailed case history – which in the 19th century produced some of the finest descriptions of patients ever written – had all but disappeared from the neurology journals when Dr. Sacks started writing, and, even today, it is rare. The great 19th-century neurologists, lacking scans, EEGs, and statistics, perfected their observational skills and the art of talking to patients so as to help them describe how those patients’ mental experiences were altered by their brain problems.
With the advent of modern lab and scanning techniques, these observational and communicative skills atrophied. The journals changed, too. Detailed accounts of individual patients increasingly disappeared, replaced by group studies of ‘subjects,’ described in more abstract, statistical terms, based on their scans and scores on tests. Instead of reporting what was unique about a patient, studies reported what was average about a population. And averages smear out what is unique about individuals.
The uniqueness of the individual is the core of Oliver Sacks’ clinical work. To better understand his patients, early in his career, he literally moved into the hospital he worked at and did extra call – years of extra call. And in the observations, he saw clearly: people suffer from illness, but they aren’t defined by illness. Sacks reminds us that every patient has a story to tell – and that a passionate healer is more than simply a member of a team.
Doidge goes even further: he flirts with the idea that the scientific journals have been tainted by a collective amnesia about the uniqueness of individuals. He notes the “reproducibility crisis” – that many published findings can’t be reproduced – and he wonders if this stems from a scientific community that focuses on the average and not the exceptional. In an otherwise thoughtful piece, Doidge seems to slip into the romantic.
But if Doidge looks for larger meanings, we don’t need to. Sacks’ work is the celebration of the patient – in her suffering, yes, but in her larger context. Awakenings was published more than four decades ago, but the writing remains fresh in many ways because the central message does.
Reading of the Week. Every week I pick articles and papers from the world of Psychiatry.