Abstract:
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Purpose: The ELTHI diving study has shown that professional divers are three
times more likely to report 'forgetfullness or loss of concentration' than age
matched, non-diving off-shore workers (1). This finding has been replicated in
objective neuropsychological testing. We hypothesised that this may be due to
gas microemboli generated during decompression and that 'forgetful' divers
would have a greater number and/or severity of white matter lesions (WML) on
brain magnetic resonance images (MRI). The aim of this study was to compare MRI
in a group of 'forgetful' professional divers with MRI in 'non-forgetful'
divers and other 'non-forgetful' off-shore workers
Methods and Materials: 291 subjects, with no history of head injury, matched
for age and IQ (98 'forgetful' divers, 98 'non-forgetful' divers and 95
'non-forgetful' off-shore workers) were imaged on a 1.5T NVi system (General
Electric) using fluid attenuation inversion recovery (FLAIR), T2W axial and 3D
T1W sequences. FLAIR images were scored using a semiquantitative, modified
Scheltens scale (2) by two experienced, blinded observers. Subcortical and deep
WML in the frontal, parietal, temporal and occipital lobes and the internal
capsule were scored on a 6 point scale for each region, giving a maximum
possible white matter score of 30.
Results: 128 subjects had no WML. Scores for WML ranged from 1-18 with 102
subjects scoring between 1 and 3. The commonest location for WML was frontal.
There was no significant difference in the number of 'forgetful' divers versus
'non-forgetful' divers or 'non-forgetful' off-shore workers with WML. Because
many subjects had minor WML scores, thresholds of >6 for total WML score and
>4 for frontal WML score were applied. Comparison of groups again showed no
significant difference between 'forgetful' divers (7% had total WML score >6
and 6% had frontal WML score >4) 'non-forgetful' divers (16% and 8%) and
'non-forgetful' off-shore workers (13% and 6%). We have not yet controlled for
confounding variables such as age, hypertension or diving history
Conclusion: We have not shown an association between objectively confirmed
memory complaints in divers and WML. These results conflict with those of some
published studies (3) but confirm those of others (4,5). (1) Macdiarmid J, et
al. Underwater and Hyperbaric Medicine 2001;28 p74. (2) Scheltens P, et al. J
Neurol. Sci 1993;114:7-12 (3) Sipinen SA, et al. Undersea Hyperb Med
1999;26:61-65. (4) Hutzelmann A, et al. Acta Radiologica 2000;41:18-21. (5)
Cordes P, et al. Neurology 2000;55:1743-1745.
(J.A.R. received a Health and Safety Executive Grant.)
Questions about this event email: a.d.murray@abdn.ac.uk
Murray MD, A,
Forgetful Professional Divers Do Not Have More White Matter Lesions Than Other Off-shore Workers: The Elthi Diving Study. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3106060.html
