I think our pajamas shield us form any danger of this.
Its a completely FLAWED study, and so irrelvant.
ITs very simple... your brain is a 'muscle'. Like other muscles, if you don't use it, it decays, shrings, becomes less effective.
Work it reguarly, and LITERALLY your brain stays 'fit'.
For example... if you are a "couch potato" but are always watching "thought provoking" programming such as News, or Discovery Chanell, or History Channel, etc.
Of course if all you watch is "Fear Factor", you might have troubes.