I would not know how your therapist may dealt with this because I would think it will depend on you and the energy and the connection you both have.
From my experience, dissociation during therapy was the hardest, most gut wrenching, depression like, regression like and yet the most and the fastest path to healing because it worked sort of opposite to resistance. I cannot understate that I felt safe and trust in my therapist but I also had my husband to bounce off reality checks outside of therapy.
I had exactly same thing, auditory barriers and some visual barriers too - funny you put it that way for me it was like I cannot remember anything my T-said cause I went away in my mind but weirdly and speaking from experience and memory here, my body stayed in the room. So in essence, I felt my body stayed last time I dissociated as an infant (obviously no cognition then) and same thing this time, so no wonder I suffered both times similar ways BUT the difference this time was, when I woke up, I used my cognition - what also got me through as an adult to heal.
I told my therapist what I was learning but I also told my body until this feeling is in my body, I am not healed. intelligence does not heal body pain, only body relief relieves it for me. So what I can recall must be acknowledged, processed and go back to sub-conscious to become useful and healing. I felt if I only use my intelligence, it is no different where I was before that is how I survived for so long, using the brain to move the body mechanically - too much energy to do that...no wonder I was still dissociating.
I hope I am articulating my experience in a way that makes sense.
I woke up feeling a lot of crazy feelings that I honestly did not know what they were or what to call them. I termed them META FEELINGS. Cause it felt like waking up to 2 years worth of memories in my body that I should not be able to recall. How do you put into words an experience from the body when you are like 6 months and you are picking them consciously in adult form? It is crazy, science fiction talk.
I will just give you an example - one that I dissected well. There are still many many feelings I am going through...I also wrote all feelings in my journal - these are feelings toward the therapist. and they were murderous and treacherous. and I know now these are based on my baby instinct toward my mother who was not giving me love or attention as I wanted and also who abused me. This is my story...not sure how yours may play out.
So this is one experience that I that I digested and took what I needed:
I started to experience a lot of hunger in my transference while in dissociation. It was a weird feeling. I even voiced during therapy that I felt I was fed at the wrong time, like when I was not hungry or beyond hungry. I was not fed appropriately as a child.
the weird thing is, I always had a weird thing about eating - I must eat just in case I may not have time later on. or when there is a long weekend, I would have a little panic that I must buy food cause everything will be closed today - extremely irrational behaviour but never knew where it came from. I made the connection of my feeling in therapy and my actual experience as an adult and realized boom I have touched a real core issue.
Nowadays, I actually stopped eating for tomorrow or for later anymore. and gosh, I have not been happier! I was over eating. BTW, I just want to mention so this is clear, I do not have eating disorder or obesity. I am 5'10 and 150lbs so never had weight issue but had food panicky issues. this is just one I can see clearly how therapy helped me - making why was I always looking for or thinking of lack of food. Where did that come from? Now I know it was a body memory.
Another one quickly, when I feel now falling into dissociation, I find myself fantasizing about those days in the dark during therapy...because I also felt safe - even though also depression. so now when I feel dissociation coming on I know because I would feel like as if I want to be back in therapy and just dissociate and then I acknowledge the craving of that safety and give it to myself as a soothing. As a result, i have not been dissociating unconsciously anymore since few months now but felt it coming just did not give in - because know now - I can see dissociation dripping down. it hides tiredness or extreme need for a nap at the most inopportune moments...probably when I am triggered.
My point is prepare yourself for tsunami, to see the seeds grow as a result.
all the best to you. Also read a book called the Haunted Self. It helped me intellectually to understand. So I was not giving my body as a lamb to my therapist. I ended up almost hurting my therapy with the intensity of rage and hatred that came out from my mother in the therapy room.
Also, have a great person you can trust to keep you here and now outside of therapy.
I would not be able to allow or do this without my supportive husband. there were many times, I could not sleep or was so confused that I would ask my husband what is real and what is not. Also my work and school suffered but I did not even know it during and could only see it in retrospect. I wish I knew what I know now or someone told me but ...I digress. You may have stronger self than me or more experience with therapy in general. All these help.
Prepare yourself. You cannot do dissociation one place and have it not show other areas of your life...until you are out of the fog so to speak. Be good to yourself. All the best in this journey. It is lonely but worth it.
My humble opinion. others may have it differently.