Will MEG be a diagnostic tool? Delta waves increased after concussion in adolescents

By Malayka Gormally. This article was initially published in our Concussion Update newsletter; please consider subscribing.

A study of adolescents suggests that an increase in delta brain waves may indicate the presence of a concussion and that measuring delta waves may be a potential diagnostic tool. The findings also indicate possible longer-term consequences of concussion. The researchers used Magnetoencephalography (MEG) to measure delta waves; MEG records "magnetic fields produced by electrical currents occurring naturally in the brain." Authors Elizabeth M. Davenport et al. found that delta wave power was significantly increased in high school football players within 72 hours of a concussion. Further, this increase in delta power had not meaningfully decreased when measured post-season. Published in Brain and Behavior, the authors note that this finding suggests that "delta power remains elevated after athletes recover from clinical concussion symptoms." 

Additionally, "the finding of increased delta power, when compared to controls, is especially compelling given the tendency for delta power to decrease or remain constant in this age group." Elizabeth Davenport discussed these findings in a UCSanDiego Health press release. "'There's debate right now in the science literature over whether…[an increase in delta power] indicates damage or if it's a healing response to the damage.'" Davenport suspects that "'delta waves might be a sign of the brain cleaning and repairing itself after such an injury.'"

The study involved 24 adolescents; eight high school football players diagnosed with a concussion during the season, eight high school football players that did not receive a concussion during the season, and eight non-contact sport controls. All the concussed football players followed a return-to-play protocol and received medical clearance from a physician to return to play. However, the study did not evaluate the return-to-play protocols. The study limitation included the small sample size (24 total) and the fact that all the study participants were male.