Sudden violent shocks to the head can produce the same type of biochemical changes that are seen in Alzheimer's Disease according to research from the University of Pennsylvania School of Medicine.
The research could provide insights into how the disease develops to degeneration of the brain and loss of mental capacity.
Writing in the current issue of the Journal of Neuropathology and Experimental Neurology, the researchers describe experiments involving anaesthetised pigs which were subjected to sudden acceleration and deceleration - the kind of movements that might occur in a car accident. The pigs' heads were not subjected to impacts but the rapid movements still caused damage to the brain, leading to nerve fibres snapping.
The damage was only microscopic but it brought about chemical changes in the tissues, the researchers, lead by Dr Douglas Smith, explained. The nerve fibres began to produce a protein, Abeta, a sticky substance that accumulated in the tissues. A-beta is also seen in Alzheimer's patients and sets the stage for the degenerative process of that disease.
"Our study suggests that even moderate brain injury resulting from a tremendous change in velocity can cause axonal damage sufficient to launch an insidiously progressive degenerative process," Dr Smith said.
This process occurs over many years in Alzheimer's patients and its onset in most cases is age-related.
Previous studies have shown that there is an association between brain trauma - as, for example, that experienced by boxers - and an increased risk of developing Alzheimer's.