MONDAY, July 12 (HealthDay News) -- A new study suggests that
Alzheimer's disease develops slower in people with bigger heads,
perhaps because their larger brains have more cognitive power in
It's not certain that head size, brain size and the rate of
worsening Alzheimer's are linked. But if they are, the research
findings could pave the way for individualized treatment for the
disease, said study co-author Lindsay Farrer, chief of the genetics
program at Boston University School of Medicine.
The ultimate goal is to catch Alzheimer's early and use
medications more effectively, Farrer said. "The prevailing view is
that most of the drugs that are out there aren't working because
they're being given to people when what's happening in the brain is
too far along," he said.
A century ago, some scientists believed that the shape of the
head held secrets to a person's intelligence and personality --
those views have been since discounted. But today, research
suggests that there may be "modest correlations" between brain size
and smarts. Still, "there are many other factors that are
associated with intelligence," stressed Catherine Roe, a research
instructor in neurology at Washington University School of Medicine
in St. Louis.
Nevertheless, there could be a connection between the size of
the brain and how many neurons are available to "pick up the slack"
when others go dark because of diseases such as Alzheimer's. The
new study, published in the July 13 issue of
Neurology, explores that possibility.
The study authors examined the medical records of 270 patients
with Alzheimer's. They looked for links between brain shrinkage,
head circumference -- an indicator of brain size -- and the
progression of their disease.
After adjusting their results so they wouldn't be thrown off by
factors such as the age and ethnicity of the patients, the
researchers found that patients with larger head sizes tended
toward less brain atrophy. Also, their dementia was less
While the difference between larger-headed and smaller-headed
people was significant from a statistical point of view, study
co-author Farrer said it's impossible to pinpoint exactly what the
difference means in terms of how the brain works overall.
The research doesn't confirm that brain size and the speed of
the disease are directly connected. But if there is a connection,
what's going on? "One possible explanation is that larger heads,
and therefore larger brains, contain more nerve cells and
connections between cells," reasoned study lead author Dr. Robert
Perneczky, a researcher at the Technical University of Munich in
Therefore, he said, more brain cells have to die before "the
threshold is crossed where brain damage leads to cognitive
impairment and other symptoms of dementia."
Roe, the neurology instructor, said the study appears to be
valid and useful, adding that it suggests that three things are
connected: brain size, the shrinking of the brain and the
progression of Alzheimer's disease.
Whatever your head size, she said, "the message is that the
important thing is trying to keep your brain as healthy as possible
throughout life, which hopefully will allow you to cope better with
diseases like Alzheimer's if they occur."
There's much more on Alzheimer's disease at the