Decreased delta power in quantitative EEGs has been found to be associated sometimes with complicated depression, chronic migraine, closed posterior head/neck injury, alcoholism, and a subgroup of patients who display lack of control over repetitive thoughts and behaviors and minor motor symptoms (Gerez-Malo &amp; Tell-Valdes, 1996).&nbsp;Low voltage delta can also indicate an old injury or a series of injuries (such is the case with professional athletes (soccer, rugby, and football players) who take many blows to the head.<br><br><p style="text-align: center;"><img src="@@PLUGINFILE@@/football-player-z-scored.png" alt="Figure : A football player who sustained many concussions and blows to the head. He experiences short term memory impairment" width="723" height="942" class="img-responsive atto_image_button_middle" style="font-size: 1rem;"></p><p style="text-align: center;"><span style="font-size: 1rem;">Figure : A football player who sustained many concussions and blows to the head. He experiences short term memory impairment</span></p><p style="text-align: center;"><span style="font-size: 1rem;"><br></span></p>