A survey was performed on a specific occupational group of compressed air divers--the professional abalone divers of New South Wales. One aspect of this survey included the use of psychometric screening tests to elicit evidence of impaired intellectual capacity, which may be related to the compressed air diving. Results of the survey indicate that there is suggestion of intellectual impairment in almost half of this diving population. The fact that this diving group exposed themselves to much greater decompression stress than the more conventional professional diving groups suggests that these results should not be extrapolated to other diving populations. The results are supportive of the anecdotal beliefs that exist regarding this highly selective diving group, i.e., that a syndrome of reduced intellectual capacity (dementia or "punch drunkenness") may be present.