My Son Was Diagnosed With A Left Petreus Apex Meningioma

My son was diagnosed with a left petreus apex meningioma in December. The surgeons have decided to monitor it by mri follow up in 12 months time. He has developed hearing problems, loss of hearing then echoing and thumping sounds. This has lasted 5 days now and is this a sign that the tumour is increasing and should we ask for an earlier appointment of see our GO to rule out other causes?