What is mild cerebral dysrhythmia?

ABNORMAL EKG: It means what it says.Mild irregularity in heart rhythem on ekg.

EEG abnormality: "dysrhythmia" describes an abnormality in a normally regular rhythm, such as heart rhythm (best seen with an ekg). The brain's electrical activity is also somewhat rhythmic, depending on the conditions in which it is measured by eeg. So "cerebral dysrhythmia" is an abnormality seen by eeg. This might suggest a focus which could generate seizures, but often isn't. Ask your neurologist.

EEG abnormalities: This is an old term for various abnormalities of the electroencephalogram. While i'm not a neurologist or electroencephalographer, i'd caution you against folks who may interpret these in a way that is not evidence-based. Especially if you've been told that this will be reflected in behavior or reflects a need for medication or supplements without clear symptoms, get another opinion.