After reading that material, I sought out a neurofeedback practitioner who works in the style that Fisher and van der Kolk recommend. I've found it helpful and recommended it to family and friends. Several have reported cognitive improvement, including one who said that her "brain fog" was gone.
I've looked into the research literature on neurofeedback and it's unfortunately rather poor, but there are some interesting recent results in the work of Ruth Lanius. My own feeling, FWIW, is that neurofeedback+psychotherapy is able to reach levels of the nervous system that talk therapies alone cannot, because many effects of trauma are encoded in nonverbal parts of the brain.
There are many products out there that use the name "neurofeedback", but if you contact the company the makes the system that Sebern Fisher works with, they will send you a list of practitioners in your area. The recommended approach is to find a psychotherapist who incorporates neurofeedback into their practice. There aren't many of those, but there are some, and in my experience it makes a big difference, so big that it becomes a puzzle why this practice is still so little known.
Whatever you end up trying, please don't give up. It can take a long while to find something that works for you. My experience was that most therapies I tried just didn't go deep enough, and my problems would "snap back" into place no matter what happened in the sessions. It was frustrating. What's different about neurofeedback, in my experience, is that it's able to "talk" directly to the brain in a way that is uncorrelated with the rest of what therapists do. I'm not saying it's for everybody, but it's worth a try if nothing else has helped.