[ksaj]

Stimulation is necessary. I just recently read that one of the best ways you can stave off or slow down dementia in dogs is to give them the time to sniff to their heart's content.

Lack of stimulation for humans can be counteracted by doing things like active reading, exercising, which you've added a tactile element to, etc. They say something similar about hearing aids for age-related hearing impairment, too.

Living passively and without allowing your senses to do what they are supposed to do seems to atrophy them and their connected brain bits over time.