Which hearing aid is best for slight hearing loss?

Hi, my mother is suffering from slight hearing loss. I know that is due to her age. But she is not accepting that she has some problems with hearing. Most of the time she is making problems due to this. I am concerned whether this will affect her mental health. So we brought her to an ENT nearby Toronto. He told us that this is an age-related hearing loss, known as presbycusis and he suggested wearing a hearing aid for this problem. Also, he referred us to an audiologist for further treatment and examination. Now we are waiting to take an appointment with the audiologist. Before that, I would like to know more about hearing aids. I searched for these hearing aids. I read about many varieties, but now, I am confused to select one. So I asked to one of my friends. She suggested me to buy ITC hearing aids. Is this a good one? Which one is the best? If anybody knows about this, please help me with your replies.