Mr. Khuliso, a 68-year-old retired teacher, is brought in by his daughter. Over the past six months, he has shown significant changes: he places inedible objects in his mouth, struggles to use common tools like a fork, and shows reduced concern for social rules. On examination, his cognition is moderately impaired. His MRI reveals cortical atrophy.

Which of the following terms best explains Mr. Khuliso's tendency to put objects in his mouth?