1. Answer: C. TWs are a distinctive but nonspecific EEG pattern originally described in a stuporous patient. The pattern is most often associated with renal failure, hepatic encephalopathy, and anoxic brain injury.

2. Answer: B. Focal delta activity is the classic electrographic sign of a local disturbance in cerebral function. If continuous delta, typically, a structural lesion is present. If no structural lesion is seen on CT scan or MRI of the head, it may be seen in the setting of trauma or postictal state after a seizure.

3. Answer: B. Prolonged P-100 is diagnostic of an abnormality in the optic nerve anterior to the chiasm. The retrochiasmatic portion of the optic nerve is not well tested with visual evoked potentials. The temporal portion of the optic nerve never crosses.

4. Answer: A. The early signs of dementia on EEG are reflected with slowing of the alpha frequency. The lower end of normal for alpha frequency is approximately 8.5 Hz. Medications can slow this down and therefore need to be excluded. The other answers are seen in disorders rather than just dementia.

5. Answer: A. Patients with transient global amnesia typically have normal EEG readings. Multiple different types of EEG readings, however, have been described such as bitemporal delta or bioccipital theta.

6. Answer: B. The EEG shows a fairly typical repetitive pattern of BiPEDs (periodic epileptiform discharges) such as TWs, approximately 1 to 1.5 seconds apart. These are usually present during wakefulness and disappear during sleep. Periodic synchronous discharges are the hallmark of the disease.

7. Answer: C. Slow roving eye movements are typically seen during the drowsy state. Sleep spindles are part of stage II sleep. Rapid eye movements as stated are part of REM sleep. Periodic leg movements can be seen in any stage of sleep.

8. Answer: B. Idiopathic generalized epilepsies are genetic epilepsies that are not symptomatic or cryptogenic. Juvenile myoclonic epilepsy and absence are two of the more common generalized idiopathic epilepsies. The others listed are symptomatic (West syndrome, Lennox-Gastaut syndrome) or localized (autosomal dominant frontal lobe epilepsy).

9. Answer: F. All of the above are common EEG artifacts.

10. Answer: B. Any destructive lesion can clearly attenuate the amplitude of normal rhythms. The other options would not likely be causes of amplitude differences comparing hemispheres.

11. Answer: E. All of the above are contraindications. History of epilepsy, however, is a relative contraindication.

12. Answer: B. Prolongation of the waveform on visual evoked potential would help support the diagnosis of optic neuritis. This is a demyelinating process, and therefore, there will be delay in transmission.