Feeling ‘foggy’ the top predictor of adolescents’ slow recovery from sports-related concussion

KEYSTONE, Colo. – Results from an unpublished study indicate that cognitive factors -- feeling “foggy” in particular -- are the most accurate predictors of which young athletes will have a slower recovery from a sports-related concussion.

Of the 21 symptoms of concussion, feeling foggy predicts worsened outcome more than any other, said Michael W. Collins, PhD, of the University of Pittsburgh Medical Center. “No wonder we can’t assess this injury.”

Collins made his comments during the American Orthopaedic Society for Sports Medicine 2009 Annual Meeting, held here.

Concussions among football players

Collins and colleagues investigated 180 consecutive concussions in high school football players beginning at a maximum 2.5 days post-injury and ending when they returned to baseline. They divided the athletes into two groups: those taking 10 days or more to recover and those taking less than 10 days.

On average, 43% of the football players took less than 10 days to recover and averaged 5.7 days, he said. In the greater-than-10-days group, the average was 29.2 days to recover.

The researchers then looked at four factors that correlated with the quick vs. protracted recovery: neuropsychiatric, cognitive, physical (migraines) and sleep disturbance.

The individual factors that correlated most with protracted outcomes were the cognitive factors, including attention problems, memory dysfunction, fogginess and fatigue. Sleep and physical factors tied for second, and psychiatric factors were least predictive factors.

Defining “fogginess”

Fogginess was the overall most predictive factor, and concentration problems, nausea, vomiting, dizziness and headaches were in the top 10.

“What is fogginess? Athletes tell me that it is like going from a high-definition TV to a standard TV, or that they are one step behind themselves, like they are hung-over but they’re not,” he said.

A better understanding of concussions will improve orthopedists’ ability to predict which athletes will experience a slower recovery. One fact, he said, is that younger people recover slower from these injuries than adults.

According to Collins, when a person experiences a concussion, the cells release potassium into the extracellular space, which results in an increased demand for glucose as the brain demands energy to address the injury. At the same time, calcium migrates from outside the cell to inside the cell, resulting in vasoconstriction, reduced blood flow and a reduced energy supply.

“Kids are different. They are more glutamate-sensitive, which is a key neurotransmitter to this illness. The developing brain is more vulnerable,” he said.

Likewise, “Concussion is not a structural brain injury; it is a metabolic crisis, and it cannot be seen on CTs or MRIs,” Collins added. “And what we have learned is that once these changes happen, there are two things that you do not want to do: get hit in the head again, and increase energy demand. My thesis is that you need complete resolution of this before allowing a return to play.”

Reference:
Collins MW. Update: Concussion. Presented at the American Orthopaedic Society for Sports Medicine 2009 Annual Meeting. July 9-12, 2009. Keystone, Colo.