Chronic traumatic encephalopathy (CTE) is a degenerative brain disease that may be found in athletes, soldiers, or anyone who may have experienced repetitive brain trauma. Research from a new study suggests that the symptoms of CTE begin in two possible ways. In some cases, a person’s behavior or mood begins to change before other indications of the disease appear, while in other cases, a person’s thinking capability shows the damage first.

“A triad of cognitive, behavioral, and mood impairments was common overall, with cognitive deficits reported for almost all subjects,” wrote the authors of the study.

Both Amateur And Professional Athletes

Once known as dementia pugilistica because it was discovered in boxers, CTE is confirmed neuropathologically through an examination of biopsy tissue from the brain or through whole autopsies of the brain. For the study, scientists performed post-mortem examinations of the brains of 36 male athletes, which confirmed a diagnosis of CTE. None of the athletes, aged 17 to 98, had other brain diseases, such as Alzheimer's. Most had played amateur or professional football, while the remaining had been wrestlers, boxers, or hockey players.

The goal of this study was to retrospectively examine the symptoms of CTE once the disease had been confirmed after death. Along with reviewing the athletes' medical records, researchers conducted interviews of family members, who were unaware of the neuropathologic findings discovered post-mortem. Families were asked about the athletes' life and medical history, in addition to changes in thinking, memory, behavior, mood, motor skills, and ability to carry out daily living tasks.

The results, though unsurprising, roused concern. Of the athletes with CTE, three showed no symptoms at the time of death. On the other hand, a total of 22 had shown behavior and mood problems as their first symptoms, while 11 had cognitive issues — memory and thinking problems — as their first symptoms. Those with behavior and mood problems experienced their first symptoms at a much younger age — usually, at an average age of 35. Meanwhile, the average age for a first show of symptoms in the group displaying cognitive problems before other damage was 59.

Almost all of the athletes in the mood/behavior group eventually experienced cognitive problems. Fewer among those who first developed thinking problems eventually experienced either mood or behavior symptoms: 64 percent experienced mood symptoms, while just a little more than half experienced behavioral issues.

Painful Memories

Family members reported that nearly three-quarters of those in the mood/behavior group were "explosive," compared with just 27 percent reported as exhibiting those behaviors in the cognitive group. Roughly the same percentage in the first group was described as verbally violent, compared to 18 percent in the second group; 86 percent of the mood/behavior group showed symptoms of depression, compared to 18 percent of the cognitive group.

Finally, those closest to these athletes described 64 percent of the mood group as being "out of control," while a full 68 percent were physically violent, compared to 27 percent and 18 percent, respectively, of the cognitive group.

"This is the largest study to date of the clinical presentation and course of CTE in autopsy-confirmed cases of the disease," Robert A. Stern, a professor of neurology and neurosurgery at Boston University School of Medicine, stated in a press release. He noted that the findings should not be viewed as definitive, as a comparison group of former athletes without CTE did not participate in the study.

Source: Stern RA, Daneshvar DH, Baugh CM, et al. Clinical presentation of chronic traumatic encephalopathy. Neurology. 2013.