DATELINE: 28th April 2001

TWO SIDES OF THE BRAIN
Two research studies into whether diving and brain damage are linked have reached contradictory conclusions. One says "yes", the other says "no".
One project, conducted on German Navy divers by Christian-Albrechts University in Kiel, compared 25 non-divers with a similar number of divers averaging more than 15 years' diving activity and over 1500 dives. Brain scans were taken, and tests made for mental abilities and motor skills.
The study found no differences between patterns for the two groups, concluding that long-term diving was safe if decompression illness was avoided. It said previous studies which had found links between diving and brain damage had used divers who, unlike the Kiel project volunteers, had suffered from DCI.
Meanwhile, a study by the University of Berne in Switzerland concluded that long-term diving might be a factor in causing brain damage, in addition to the more accepted link between brain effects and incidences of DCI. Scans were taken of 52 divers and 52 non-divers.
41 lesions [damaged tissue] were found in 19 of the divers, compared to seven in six non-divers. The affected divers had not performed more or deeper dives than those unaffected. The incidence of lesions in divers thus rose fivefold - more than could be accounted for by the percentage of divers calculated to suffer bends.
The conclusion is that either more divers suffer mild bends, with subsequent brain damage, without realising they have suffered a hit, or that diving over time is a factor in causing brain damage.
"It goes to show that DCI is not fully understood, and that we still have much to learn," said Dr Phil Bryson of the Diving Diseases Research Centre. "Anyone who says otherwise is talking rubbish. These studies represent food for thought, but I'd put them into the 'interesting but a long way to go' category."

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