The onset of<unk>  can be triggered by a number of activities, all of which involve use of the brain's inhibitory system. Activities that engage this system include multitasking, working in an environment with disruptive background noise or after a lack of sleep, and rapidly changing focus during a prolonged period of<unk> . DAF can also be brought about by performing concentration-intensive tasks such as puzzle-solving or learning unfamiliar ideas. External factors such as stress resulting from emergencies, exams or work deadlines can also induce DAF. Any illness or injury to the brain that interrupts the brain circuits involved in maintaining<unk>  and inhibiting external stimuli may also contribute to the development of<unk> .
Directed attention fatigue
Sundowning
Sleep state misperception
Listener fatigue
Stress concentration
Repressed memory
Wandering 
Anxiety