Boxed – Things I learned after lying in an MRI machine for 30 hours

Original Article ↗ Hacker News Discussion ↗

Lying in an MRI scanner for 30 hours prompted reflections on sensory deprivation, with many readers comparing MRI sounds and confinement to meditation, sleep, or even float tanks, while others described intense claustrophobia and anxiety. Commenters traded practical advice on ear protection, hearing issues, and the surprising benefit of earplugs or noise cancellation for understanding speech in noisy environments. The thread also branched into MRI safety anecdotes, the physics of strong magnetic fields, and experiments with apps or sites that show truly random images to recreate the author’s reported surge of unexpected mental imagery.

Overall MRI Experience

  • Many commenters find MRIs relaxing or meditative, often falling asleep despite loud noise and confinement.
  • Others experience intense claustrophobia; some report developing mild claustrophobia after a single unsedated scan.
  • Coping tips include closing eyes before entering, imagining sci‑fi “healing tubes,” asking for cooler airflow, and using mirrors to see outside the bore.
  • Several people admire the 30‑hour volunteer as heroic; an MRI tech notes that in routine practice only a small fraction of patients need sedation.

Noise, Earplugs, and Hearing

  • Multiple users report hearing speech better in loud environments when wearing earplugs or noise‑canceling devices, linking this to reduced background noise.
  • Specific product categories mentioned: “flat attenuation” / musician earplugs (custom and off‑the‑shelf), concert‑oriented plugs, and consumer brands; experiences range from “life‑changing” to “overhyped.”
  • Some warn that earplugs can make internal sounds and tinnitus more salient and that “silence” can feel unsettling.
  • A few recommend professional hearing tests; availability and cost of testing is discussed as somewhat opaque.

Desire for a True Random‑Image Stream

  • Several commenters like the idea of an app showing uncurated random images to stimulate unexpected associations.
  • Links shared include older collage/screen‑saver tools, Wikimedia “random file,” random photo generators, and a quickly built site that streams random photos.
  • There is mild concern about some sources being biased toward “artsy” content, reducing true randomness.

Safety, Metal Objects, and Quench

  • Anecdotes include: feeling magnetic field changes through a wedding ring, a burned wrist from a metal watch near a research magnet, and a serious accident where people wearing metal weights and gear were pulled into a scanner.
  • Discussion of the emergency “quench” button: it dumps helium and kills the field but is costly and, according to cited material, may not reliably release stuck objects.
  • Some MRI staff apparently allow nonmagnetic rings; others in the thread consider this risky, given uncertainty about alloy composition.

Sensory Deprivation, Magnetic Fields, and Sound

  • Some compare the mental state in the scanner to float tanks: heightened imagery and focus for some, nausea or insomnia‑like discomfort for others.
  • There is curiosity about whether strong fields (>2T) or RF exposure affect cognition; commenters find the idea plausible but do not present firm conclusions.
  • Opinions on MRI sounds diverge: some hear them as musical or soothing (even listening to MRI recordings later), others as jackhammer‑like and unbearable.

Aphantasia and Imagery

  • Aphantasic commenters say they recognize people and objects visually in real life but cannot voluntarily picture them, suggesting recognition without mental imagery.