Before the board police strike this one, know it's all things we were all taught and all fair game for orals. I am talking about techniques of preparation. I am not describing any specific thing anyone has quizzed anyone about during orals. These are some techniques I and others have used:
Describe to someone how you would approach an acute CVA, SCI, TBI etc, from the assessment phase, through rehab and into community re-integration. Describe the meds you might use, their mechanisms of action, and side effects/risks. Discuss preventions and potential complications and how you would watch for them, assess them and treat them (DVT, decub, spasticity, etc.) Describe how you would integrate various members of the rehab team and how you would lead weekly team meetings.
Describe for someone how you assess function in a rehab pt and when they should be admitted and when they should be discharged. Know how you determine whether they can go home or need to go to a facility or with family.
Go to your MRI Dept, and ask a radiologist to quiz you on things such as spine xray and MRI. See if your interpretation agrees with his. Then take the films to another PM&R and describe your treatment approach based on a theoretical pt c/o pain that the MRI would explain.
Describe to someone else how you might write out a prescription for therapy for a given MSK problem. Have them give you various MSK conditions to do this for - lumbar strain, epicondylitis, cervical HNP, plantar fasciitis, etc. Do the same for a neuro problem. Describe other treatment approaches you might use - meds, braces, injections and when you would consider a surgical referral.
Have someone give you an EMG report and then tell them your interpretation. Do the same with lab reports. Correlate it with theoretical conditions.
Have the person you are describing these things to interrupt you periodically to throw you curve balls and request references. Know the risks and pitfalls of every treatment you describe.
The person quizzing you should optimally be someone with more experience than you. They should not give you any feedback into whether your answers are right or wrong until after you are done.
To simulate the anxiety you might have, do all the above after going without sleep for an entire night and then drinking 6 cups of coffee.