Brynne Henn, 26, leaned back onto a pristine white couch and settled white-and-red headphones over her ears. She picked up a handset, grasping one buzzer in each hand, closed her eyes, and the session began.

The room was quiet. Through the headphones, Henn heard an alternating tone — first in the right ear, then the left, back and forth. The handset buzzed in synchrony, right-left-right-left, part of a trauma treatment that also involves recalling painful memories. She turned her thoughts to the day her brother, Nate, died.

Read more at The Washington Post.