Wow, this actually has a name!! I’ve been experiencing this every since I was a little girl – I respond to all three triggers. I always wondered what this was and it just never occurred to me that other people might be experiencing what I did (in particular, the auditory and visual triggers). These experiences are so unbelievably pleasant and ultra-relaxing. Trance-like, out-of-body even…I just go to another place. I have a vague recollection of trying to describe what I was feeling to friends throughout my childhood and just beyond and they had no idea what I was talking about/looked at me like I was a little out there. So I’ve considered it a uniquely personal experience up until now. Very cool! I’ve got some research to do and some amazing relaxing videos to watch.
Sounds work ok, but I have always got the most (for lack of better word) intense asmr from touch. They don’t even have to touch me. When I was in 4-5 grade I would get it when someone I dont know well touched something close to me like my favorite stuffed animal or the eraser I use every day at school. Now I can just get lightly touched on the face and it will happen. I can just think about it and get it now.

The first study to perform actual brain imaging (fMRI) on subjects currently experiencing ASMR tingles (as opposed to individuals who were merely able to experience the phenomenon) was published in BioImpacts in September 2018. Subjects viewed several ASMR videos with a screen and headphones while inside the MRI scanner. The study found a significant difference in brain activation between time periods when the subject reported tingling (communicated by pressing a button), as compared to time periods when they were watching a video but not reporting tingling (communicated by pressing a different button, to control for brain activation effects caused by merely pressing a button). They concluded that "the brain regions found most active during the tingling sensations were the nucleus accumbens, mPFC, insula and secondary somatosensory cortex", and suggested that these were similar to "activation of brain regions previously observed during experiences like social bonding and musical frisson".[29]

According to Setz, this citation generally alludes to the effectiveness of the human voice and soft or whispered vocal sounds specifically as a trigger of ASMR for many of those who experience it, as demonstrated by the responsive comments posted to YouTube videos that depict someone speaking softly or whispering, typically directly to camera.[12][13][14]
Replies to this post indicated that a significant number of other people had experienced the sensation which "okaywhatever" described - also in response to witnessing mundane events. The interchanges precipitated the formation of a number of web-based locations intended to facilitate further discussion and analysis of the phenomenon for which there were plentiful anecdotal accounts,[12][24] yet no consensus-agreed name nor any scientific data or explanation.[17]

In the limited, small studies that have been done investigating ASMR, there do appear to be brain abnormalities in people who experience ASMR, though this is far from confirmed. But some studies did find that people who experience the phenomenon appear to have brains that are wired differently when it comes to the areas that react to sensory perception. Instead of two sensory areas having a clear connection in their brain, a tinglehead’s sensory areas of the brain appear to blend together to some degree. Some neurologists who have studied the phenomena even think ASMR could be related to the bizarre condition of synesthesia, where a person can hear smells or see music.
Many of those who experience ASMR report that some specific non-vocal ambient noises are also effective triggers of ASMR, including those like the sound of rain, fingers scratching or tapping a surface, the crushing of eggshells, the crinkling and crumpling of a flexible material such as paper, or writing. Many YouTube videos that are intended to trigger ASMR responses capture a single person performing these actions and the sounds that result.[15]