In what situation would a physician recommend long-term EEG monitoring?

Long-term EEG monitoring is primarily recommended to track seizure frequency and patterns in patients with epilepsy or other seizure disorders. This type of monitoring allows physicians to observe the electrical activity of the brain over an extended period, which can provide valuable insights into seizure characteristics, including their onset, duration, and the areas of the brain involved. By analyzing this data, the healthcare provider can better understand the patient's condition, refine treatment plans, and improve overall management of seizures.

In contrast, the other options focus on aspects that are less suited for long-term EEG monitoring. Investigating sleep disorders typically involves other specific sleep studies, assessing cognitive function is usually done through neuropsychological testing or imaging rather than EEG, and evaluating muscle activity is more appropriately conducted with electromyography (EMG) rather than EEG. Thus, the situation of tracking seizure frequency and patterns aligns perfectly with the primary use case for long-term EEG monitoring.