How someone’s brain living with adhd can perceive information from outside world that could turn impact performance in class?

The overall performance of a child in class is marked low considering all prospects of his behavior and personality

Explanation:

A person suffering  from ADHD usually suffers from problem like lack of attention, hyperactivity and impulsivity. Most of the children in pre school lack attention/concentration in class and thus most of the time looks wandering, challenged to grasp details and diverted.

Children with hyperactivity/impulsivity fidge or squirm on their seats or they are always in a "go on" situation irrespective of place where they are. they talk endlessly and had trouble in waiting for their turn.

Thus, the overall performance of a child in class is marked low considering all prospects of his behavior and personality