July 13, 2010 at 8:22 AM ETLinda Carroll writes: It used to be insulting if you were told you had a big head. Now, it turns out — ego, aside — that it might actually be a compliment. A large cranium equals a big brain, researchers say. And if you’re struck by Alzheimer’s disease, having a dominant dome on your shoulders might help preserve your thinking and memory, a new study shows.As a general rule, the larger your head circumference measures, the more room there is for brain cells. That means that you’ve got all those extra neurons waiting like the cavalry in reserve when a brain disease like Alzheimer’s strikes, says the study’s lead author Dr. Robert Perneczky, a researcher at the Technical University of Munich in Germany.“These findings add weight to the theory of brain reserve, or individual capacity to withstand changes in the brain,” says Perneczky about the new research published in Neurology. “Our findings also underline the importance of optimal brain development early in life, since the brain reaches 93 percent of its final size at age six.”Perneczky says we might be able to prevent some cases of Alzheimer’s disease if we could make sure everyone’s brain got a chance to develop to its fullest potential. Unfortunately, that news might be a little late for anyone already old enough to be reading about his study.Perneczky scanned the brains of 270 people with Alzheimer’s disease and then measured their skull sizes and tested their thinking abilities. The ones with larger-sized heads did better on tests of memory and cognition.So, does that mean that mean you should be investigating nursing homes if you have a small head?Not yet, says Dr. Steven Arnold, a professor of neurology and psychiatry and director of the Penn Memory Center at the University of Pennsylvania in Philadelphia.While the German study results are interesting, the tests show a lot of “scatter,” says Arnold. Which means that while there is a general trend for larger head size to be protective against mental decline, there are a lot of other factors at work.As an example of that, Arnold points to Albert Einstein.“The average male brain is about 1,400 g or 3 lb.,” says Arnold. “Albert Einstein’s brain was measured after his death at 1,230 g and I think we all agree he was intelligent.”So, clearly there are exceptions to the rule.Do you worry about the size of your head? Tell us in the comments.