I think mostly the touch screen. Most devices I have seen or used (and those my mother has tried) need a fairly bulky case so fingers do not interfere with the

I think mostly the touch screen. Most devices I have seen or used (and those my mother has tried) need a fairly bulky case so fingers do not interfere with the screen around the edge (maybe software fixes already available). Holding the phone too gingerly for fear of breaking it also leads to drops. She is someone that payed $2-$3k for a brand new car. Fine motor control is also an issue. Her fingers skip across the screen. Buttons on a flat screen seem to be conceptually troubling. The flip phone she uses now is ok but there are way to many options. It is to easy to select them. She does well with the contact list except she did manage to block me the other day (a nice but extra option). I am planning on going to a store and get her to try an iPhone and assistive touch but we are in a rural area so trips to such places don't happen a lot. I will be watching for someone with an iPhone (is touch assistant a setting or an app?).