Use of scap electrodes went the way of bell-bottom pants. Either skull caps or small adhesive electrodes are utilized these days.
I had my test done about 6 years ago, and I had half a dozen scalp electrodes, finger oxygen monitor, and a CPAP mask with airflow sensors.
I don't have full blown apnea, but I do snore very loudly and my wife loves my CPAP because now she gets a good night's sleep as well.