The Gateway Process

It was one Army officer's assessment, not a CIA experiment. Page 25, missing from the CIA's release, reached Vice from the Monroe Institute in April 2021.

Lt Col Wayne M. McDonnell, US Army, 'Analysis and Assessment of Gateway Process' (9 June 1983; CIA release stamp 2003/09/10); Thobey Campion, 'Found: Page 25 of the CIA's Gateway Report on Astral Projection', Vice (8 April 2021)

A 1983 US Army assessment of the Monroe Institute's Gateway Experience training, released by the CIA in 2003.

Sources3 sources

Primary source

Lt Col Wayne M. McDonnell, US Army Operational Group, Analysis and Assessment of Gateway Process (CIA-RDP96-00788R001700210016-5), 1983, memo of 9 June 1983; 'The Gateway Experience: Brain Hemisphere Synchronization in perspective'The report's own account of Hemi-Sync: the tapes relax the left hemisphere, put the body in a virtual sleep state and bring the hemispheres into coherence; released by the CIA with the stamp 'Approved For Release 2003/09/10'.
place the physical body in a virtual sleep state, and bring the left and right hemispheres into coherence

Scholarship

Thobey Campion, Found: Page 25 of the CIA's Gateway Report on Astral Projection, Vice, 2021, 8 April 2021Page 25 was missing from the CIA's released copy; the Monroe Institute held it and its marketing director emailed Vice the full report in 2021.
Sitting buried in the Monroe Institute archives in Faber, Virginia, was page 25 of The Gateway Report.