July 12, 2010 -- People suffering from Alzheimer's disease who have large heads seem to have better thinking skills and memory compared to those with Alzheimer's who have smaller heads, new research shows.
In the study, published in the July 13 issue of Neurology, researchers looked at Alzheimer's patients with similar levels of brain cell loss due to the disease.
Head size is one way to measure brain growth and brain reserve, says study researcher Robert Perneczky, MD, of the Technical University of Munich in Germany. While brain growth is determined, in part, by genetics, size also is influenced by nutrition, infections and inflammations of the central nervous system, and brain injuries.
"These results add weight to the theory of brain reserve, or the individual capacity to withstand changes in the brain," Perneczky says in a news release. "Our findings also underline the importance of optimal brain development early in life since the brain reaches 93% of its final size at age six."
Therefore, he says, "improving prenatal and early life conditions could significantly increase brain reserve, which could have an impact on the risk of developing Alzheimer's disease or the severity of symptoms of the disease."
Alzheimer's and Head Size
Perneczky and colleagues studied 270 people with Alzheimer's, with an average age of 75, taking tests of their memory and cognitive skills and measuring each patient's head circumference.
They conducted MRI scans of the patients' brains to determine the amount of cell loss.
Larger head size was associated with a greater performance on thinking and memory tests, even when it was determined that all had an equivalent degree of brain cell loss, the researchers say.
For every 1% of brain cell loss, an additional centimeter of head size was associated with a 6% greater performance on memory tests, the researchers say.
This finding supports the notion that head circumference and presumably brain size "offers protection against AD symptoms through enhanced brain reserve," the researchers write.