The September issue of the Journal of Neuropathology and Experimental Neurology reports the first pathological evidence that repetitive brain trauma in contact sports may be associated with motor neuron disease (MND) or ALS — popularly called Lou Gehrig's disease.

The suspicion that traumatic head and neck injury might trigger ALS began more than 100 years ago. One recent study showed the incidence of ALS among 7325 professional Italian soccer players was 6.5 times higher than expected. In addition, the risk for ALS for veterans of the 1991 Gulf War was 2-fold 10 years after the conflict. Repetitive concussions are associated with chronic traumatic encephalopathy (CTE), a degenerative brain disease that impairs memory, destabilizes emotions, and may progress to dementia.

CTE is the focus of the Center for the Study of Traumatic Encephalopathy. In the study, researchers analyzed the donated brains and spinal cords of 12 former football players, boxers, and professional hockey players. All 12 evidenced the build-up of abnormal tau protein found in CTE. However, the spinal cords of the 3 athletes thought to have ALS also contained the abnormal protein, a finding not characteristic of sporadic ALS.

The study authors concur that more research is needed. They recommend looking at how repetitive head injury may use other biological mechanisms such as inflammation to trigger neurodegenerative diseases, the role played by genetics, and the potential for therapeutic intervention. The long period of latency between traumatic brain injury and the onset of CTE and MND could become a window for treatment that would either dampen or block the "neurodegenerative cascade" that follows such brain trauma.

Increased awareness of the cumulative effects of concussion has resulted in improved football helmet design as well as how coaches manage players.