I think the severely autistic person featured on youtube videos under cdfoakley and kgaccount show someone with the "autistic like" behaviors you discuss when it comes to constant humming and those incessant vocalizations.
Usually when proprioceptive dysfunction is explained the symptoms described are those of proprioceptive undersensitivity: bashing into things, crashing,
Since I was a toddler, I've struggled with sensory overwhelm. Namely, my mum tells me I refused to wear shoes at around 1,2 and 3 because I didn't like
MY 3 yr old son will put balls in his shirt and play. As soon as he realizes I am watching him he runs and hides. He is VERY persistent about me leaving