Neuropsychological deficits in scuba divers: An exploratory investigation

Objective: To investigate whether divers with varying levels of experience and without a history of reported decompression sickness (DCS) show neuropsychometric alterations possibly as a result of socalled repetitive silent paradoxical gas embolisms. Methods: Using reaction time as a psychometric measure, 17 experienced military divers (ED, logging between 150 and 1,200 diving hours) and eight very experienced military divers (VED, logging between 2,800 and 9,800 diving hours) with no decompression sickness (DCS) in their medical histories were compared to 23 healthy controls without any diving history, matched as closely as possible with respect to age for the two diving groups. Motor reaction time, decision reaction time and error rates were measured during completion of both simple and complex reaction time tasks. Results: Compared to their control group, VED showed significantly higher motor reaction times on both tasks and significantly higher decision reaction times in the complex task. ED were not found to be different from their respective controls. No changes in performance quality in terms of increased errors were observed in any of the tasks for either diving group. Conclusions: The findings support the proposed possibility that minimal cerebral lesions occur after diving even without DCS. Further studies with this highly selective population of very experienced divers using more elaborate neurocognitive and neuromotor tasks seem warranted. Copyright © 2011 Undersea & Hyperbaric Medical Society, Inc