A teenager has difficulty with schoolwork because he often has brief staring spells and forgets what has happened in the last few minutes. This may be a sign of

Brief staring spells with short gaps in awareness or memory can be absence seizures, a type of seizure associated with epilepsy. These episodes can interrupt learning and make it seem as though the teenager has forgotten recent events. The best answer is epilepsy; stroke, Parkinson’s disease, and multiple sclerosis do not typically cause this pattern of brief staring spells.

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