<unk>  (DAF) is a neuro-psychological phenomenon that results from overuse of the brain's inhibitory<unk>  mechanisms, which handle incoming distractions while maintaining focus on a specific task. The greatest threat to a given focus of<unk>  is competition from other stimuli that can cause a shift in focus. This is because one maintains focus on a particular thought by inhibiting all potential distractions and not by strengthening that central mental activity.<unk>  occurs when a particular part of the brain's global inhibitory system is overworked due to the suppression of increasing numbers of stimuli. This temporary condition is not a clinical illness or a personality disorder. It is rather a temporary fatigue of the inhibitory mechanisms in the brain. According to inhibition theory, it is natural for one to alternate between periods of<unk>  and distraction. Although one's efforts may involve very different tasks, each incoming stimulus calls upon the same<unk><unk>  mechanism.
Directed attention fatigue
Sundowning
Sleep state misperception
Listener fatigue
Stress concentration
Repressed memory
Wandering 
Anxiety