Nitrogen Narcosis and Performance Under Water

Abstract

Eighteen divers were tested four times under water, twice at a depth of 5 ft and twice at 100 ft. They performed three tests—digit copying, a sentence comprehension test and a manual dexterity test. All three showed a significant drop in efficiency at depth. This was small for digit copying (7-9 per cent) and manual dexterity (3 5 per cent), and somewhat larger for sentence comprehension (15-3 per cent). In all three cases the drop in efficiency was approximately the same as found at the equivalent pressure in a dry pressure chamber. This contrasts with previous results where impairment in the open sea has been considerably greater than in a dry chamber. Possible reasons for this discrepancy are discussed and it is suggested that level of anxiety may be a crucial factor.