In the final stages of life, Ötzi, the famed iceman likely suffered from brain damage, according to a new protein analysis on the famed frozen corpse.

A well-preserved natural mummy of a man who lived about 3,300 BC, Ötzi came to international attention when it was stumbled upon in 1991 by hikers on the Austrian-Italian border. Ötzi has long since been a subject of research, and apparently had less-than-perfect health, with prior studies indicating that Ötzi had bad breath, tooth decay and was predisposed to cardiovascular disease.

For the latest research on Ötzi's brain, researchers took a pinhead-sized sample of brain tissue and extracted proteins. The research also examined the remnants of proteins from blood cells, as well as clotted blood cells. The presence of clotted blood cells in a corpse basically devoid of blood provides supporting evidence to a 2007 theory that the iceman suffered some type of brain injury shortly before his death, though whether the injury was due to a blow to the forehead or from a fall after being struck in the shoulder by an arrow remains unclear.

The protein analysis is being considered a major breakthrough by the scientists, who say the use of new protein-analysis methods has enabled a pioneering protein investigation on the soft tissue of a mummified human.

"Proteins are the decisive players in tissues and cells, and they conduct most of the processes which take place in cells. Identification of the proteins is therefore key to understanding the functional potential of a particular tissue," Andreas Tholey a scientist involved in the research at Kiel University's Institute for Experimental Medicine, said in a statement

Tholey's team provided the latest technology used in the study of complex protein mixtures known as "proteomes."

"When you think that we have succeeded in identifying actual tissue changes in a human who lived over 5,000 years ago, you can begin to understand how pleased we are" with the progress, Tholey said.

The results of the protein study are published in the journal Cellular and Molecular Life Sciences.