On the research front, I've observed that there is little in the way of major scientific studies on the topic of retained reflexes. That's why I'm inquiring about people's direct experience. Portia's example with the startle reflex, for example, sounds a lot like my son.
You may not be searching for the right terms. MD/PhD types usually use the term
primitive reflexes in the literature (
other names here). Searching by individual reflexes (e.g. Moro reflex) would get more hits. Also,
frontal release sign is another technical term. If you use these terms on PubMed and Google Scholar, I guarantee that you'll get more hits than you know what to do with.
But the thing is, as Flyingmouse pointed out, this problem is generally associated with an underlying cause, rather than being something that's studied in and of itself.
This won't make me too popular, I think, but if you don't have a biomedical background, it can be very difficult to get accurate medical information online. This is because the web is full of predatory types and charlatans who talk a good spin but are actually spewing pseudoscience (
Seaweed is the best treatment for a thyroid condition!; yes, I've read that).
Using technical terms in a search instead of popular terms helps a lot. Also, if you know how to recognize reputable sites, you'll find reliable information more easily. These sites include university medical centers, .gov and other government sites outside the US, major hospitals like the Mayo Clinic and St. Jude's, and sites with a badge called
HonCode). As an example, Dr. Mercola's site is NOT trustworthy. Predatory sites like his excel at telling people lies that make them feel good while not solving problems (or making them worse).
I agree that medical decisions are personal, but also know they're best made when based on sound information. This helps avoid interventions that are useless or potentially harmful (e.g. seaweed-and-the-thyroid and anti-vax stances). It also helps you get to the right treatment with minimal delay.
I started working in the area of rare diseases 15 years ago. I know how difficult and frustrating it is to get a diagnosis. I also know how easy it is for an MD to look at an array of clinical features and not be able to see the forest for the trees --- and how easy it is for the predators to take advantage of those facts.
I'm currently privileged to be leading a project that involves a free software app aimed at helping diagnose rare diseases. The whole point of what we're doing is to ease the very messy diagnosis problem described in basic terms above. I also know that the research community doesn't have all the answers, even when there is a diagnosis. But the thing is that, it's the best we have right now.