Memory deficit caused by compressed air equivalent to 36 meters of seawater

Twenty-four students from a diving school undertook a hyperbaric chamber dive to a pressure equal to 36 m of seawater. Tests of cognitive function and manual dexterity, performed in the chamber during the 35-min bottom time and before, or after, the dive included immediate and delayed free recall of words presented as 7 lists of 15 each, recognition of previously presented words, number identification, and a forceps pickup of ball bearings. Delayed free recall and immediate free recall (primacy region) were significantly impaired, whereas manual dexterity and recognition memory were not. These are in keeping with previously reported findings but indicate that significant impairment of memory may occur in experienced divers at operational depths for air diving. Lack of effect on recognition memory suggests that cueing strategies might be useful for debriefing divers.