Susannah is admitted ten days after her first blackout seizure. She's placed in the advanced monitoring unit, which is technically for patients with severe epilepsy who need constant monitoring but sometimes takes patients when there's no room elsewhere. A nurse sits in the four-person room 24 hours per day, and two cameras hang above each bed. This provides video evidence of seizures for the hospital, and Susannah tells the reader that these videos were essential when she reconstructed her time in the hospital.
Though Cahalan positions the video evidence as an absolutely true and factual account of her time in the hospital, it's worth keeping in mind that she had to transcribe videos from a visual form to a verbal one in writing the memoir. This shows that even these "factual" accounts are subject to human nature and interpretation, and can never fully represent reality.
When Susannah is settled in the room, a nurse takes her health history. Susannah can answer most of the questions, and Mom fills in what she can't. After a few hours, an EEG technician arrives and begins to place electrodes on Susannah's head. Susannah stops cooperating and fights the technician, but finally just cries. When the technician is finished, he hands Susannah a pink backpack with the EEG box so she can remain connected but be mobile.
In comparison to Susannah's apartment, the EEG backpack is a symbol of Susannah's childish state in the hospital. She carries a tiny pink backpack, is constantly monitored, and needs a great deal of help from her parents and others—a very vulnerable place to be, and one that contrasts greatly with her "before" personality.
Susannah's difficult nature worsens. When Allen and Dad arrive, she yells at them and insists the nurses ban them from her room. She accuses Dad of being an imposter. Later that evening, a neurologist notes that Susannah is experiencing mood swings and can't stay on topic. Susannah tells the neurologist that Dad is turning into different people to trick her, and the neurologist prescribes an anti-psychotic drug. Susannah explains to the reader that her paranoid hallucinations and her belief that Dad was turning into other people is called Capgras syndrome, which doctors believe is caused by neurobiological issues such as brain lesions.
The diagnosis of Capgras syndrome (and the explanation that it's a physiological issue) makes it abundantly clear to the reader that what's ailing Susannah isn't just a mental health issue. As Cahalan offers these explanations of problems that are caused by the actual landscape of the brain, it begins to create the sense that mental health and physical health are intimately linked.
Susannah describes an EEG video in which she lies in bed in the fetal position looking upset, fiddles with her EEG cap, and grabs her phone. She then describes a hallucination. Susannah goes to the restroom but as she pulls her leggings down, she notices an eye watching her through a slit in the door. She yells, pulls her leggings back up, and returns to bed. Susannah calls Mom and quietly tells her what happened. Mom sounds frenzied, but Susannah hangs up when she hears a nurse approaching. The nurse asks Susannah to not use her phone with the EEG equipment, says that she saw Susannah on the news, and asks why she doesn't let Dad into the room. Susannah starts pulling the EEG electrodes off her scalp and tries to escape the hospital.
Juxtaposing the EEG video with Susannah's hallucination highlights the limitations of relying on the video footage as the one and only truth: though Susannah certainly appears agitated in the video, it absolutely doesn't capture her panic and paranoia that describing her hallucinations does. This also makes it clear that Susannah's truth and lived experience at this point is very, very different from what others see. Her internal identity, beliefs, and worldviews are causing her external, performed identity to become very difficult and antagonistic.