Alzheimer’s patients who have large heads have better memory and thinking skills than those with the disease who have smaller heads, even when they have the same amount of brain cell death, a new study has claimed.

“These results add weight to the theory of brain reserve, or the individual capacity to withstand changes in the brain.

“Our findings also underline the importance of optimal brain development early in life since the brain reaches 93 per cent of its final size at age six,” said study’s lead author Robert Perneczky of Technical University of Munich in Germany.

Head size is one way to measure brain reserve and brain growth.

According to the scientists, while brain growth is determined in part by genetics, it is also influenced by nutrition, infections and inflammations of the central nervous system, and brain injuries.

“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,” Perneczky said.

For the study, 270 people with Alzheimer’s disease took tests of their memory and cognitive skills and had MRI scans of their brains to measure the amount of brain cell death. Head size was determined by circumference measurement.

The study showed that larger head size was associated with a greater performance on memory and thinking tests, even when there was an equivalent degree of brain cell death.

Specifically, for every one percent of brain cell death, an additional centimetre of head size was associated with a six percent greater performance on the memory tests.

The findings have been published in the latest edition of the Neurology journal.