As we age, we become more aware of our lack of
mental capacity, especially when it comes to short-term
memory. Do we have difficulty recalling things because
we simply have too much information stored? Are the
hard drives of our brains so full it takes more time to
search out individual items, or are we simply losing our
minds? Or, has too much diving damaged our brains?
Dr. Christian Seiler, of the University of Berne,
scanned the brains of 52 divers who had completed at
least 200 dives and compared them with those from the
same number of healthy adults who had never scuba
The research showed 41 lesions in 19 of the divers
compared with seven lesions in six of the non-divers.
His conclusion was that diving increased the incidence
of one or more brain lesions five fold.
The affected divers had not performed a greater
number of dives nor at a deeper depth than the unaffected
divers, and the lesions did not appear to be
linked to other causes. Nor did the study suggest that
these brain lesions occurred in divers who had suffered
symptoms of decompression sickness, although the
study, published in the Annals of Internal Medicine,
confirmed fears that they were more common in divers
who have a PFO (patent foramen ovale).
We asked Petar Denoble of DAN for a comment
on this, but although he had not seen the paper in
question, he pointed us to another paper; Long-Term
Neurologic Damage and Brain Lesions in Recreational
Divers by Michael Knauth of the University of Medicine,
Goettingen, Germany. It reviews other research done
in Norway, the USA, Germany and Switzerland and
highlights that while divers had significantly more brain
lesions than the non-divers, there was also a correlation
between the presence of a PFO and brain lesions.
"That the number of brain lesions was also increased
in the group of divers without PFO suggests that there
are also other mechanisms for the origin of brain
lesions in divers besides PFO."
This is the conclusion in full:
"Long-term neurologic damage in the form of neuropsychological
performance or brain lesions should
neither be dramatized nor played down. Brain lesions
have so far not been linked with a reduction in neuropsychological
performance, and the neuropsychological
impairment in divers in the Swiss study occurred in relation
to quite extreme diving behavior.
On the other hand, recreational diving is a leisure
activity, and the brain is the organ to which we owe our
mental capacity and our personality. As in other areas of
life, the same should apply to diving: moderation in all
things. In any case, there is so far no evidence of longterm
neurologic damage in the form of reduction of
cerebral capacity with moderate recreational diving."