Also worth reading (though in Japanese) - Effect of Reading a Book on a Tablet Computer on Cerebral Blood Flow in the Prefrontal Cortex (2018) - https://www.jstage.jst.go.jp/article/jjh/73/1/73_39/_pdf/-ch...

Showed increased brain activity (increase in regional cerebral blood flow) was observed following reading a novel on a tablet computer compared with that after reading a printed book.