What does the presence of "sharp waves" generally indicate in EEG?

The presence of sharp waves in an EEG typically indicates potential epilepsy activity. Sharp waves are abnormal electrical discharges that can signify a focus of neuronal hyperexcitability, commonly associated with various types of seizures. In the context of epilepsy, sharp waves may appear in specific patterns that correlate with seizure activity or serve as markers for the propensity of an individual to experience seizures. This characteristic makes their presence notable during EEG readings, particularly in patients with a history or suspicion of epilepsy.

In contrast, normal brain function is generally characterized by sinusoidal waves, particularly in awake individuals, while sharp waves disrupt this expected pattern. Sleep disturbances might manifest as different waveforms, such as sleep spindles or K-complexes, rather than sharp waves. Similarly, muscle artifacts arise from muscular activity rather than originating from neuronal firing, which is what sharp waves represent. Thus, identifying sharp waves in an EEG lends critical information about the possible presence of epileptic activity.