The abuse itself seems horrific. I can understand what difficulties arise later in life, after going through sexual abuse (where she continues to rub and touch her genitals to the point of bleeding -- it's a focal point of emotional pain and prior stimulation both good and bad).
Also,when you are sensory deprived for a long time, even when you crave stimulation, you can't really handle it and can find yourself reacting compulsively when you are overstimulated by what other people just consider "normal". My situation growing up was nothing like what these kids had to deal with at such a young age, but I can see that I had some issues in terms of lack of interaction in my family -- huge sense of detachment from relationships, and just this crazy level of SILENCE that hung like a pall over the house, so that for many years later in life I just couldn't handle much actual social interaction, I would get very irritable and want to avoid people even if the interaction was good. (I think that still lingers for me today, I still feel a gap between me and other people, and a lack of investment in actually spending time with people, it drains me.) These kinds of experiences especially when the brain is rapidly developing can wreak much havoc.
I'm reminded of feral kids and how missing that small crucial window of development can rob them of what we understand as "their humanity" for years to come, if not their entire lives. And these kids are experience traumatic circumstances and/or common relational stimulation in formative times as well.