Negative neurofunctional effects of frequency, depth and environment in recreational scuba diving: the Geneva “memory dive” study
- D O Slosman1,
- S de Ribaupierre1,
- C Chicherio1,2,
- C Ludwig1,2,
- M-L Montandon1,
- M Allaoua1,
- L Genton1,3,
- C Pichard3,
- A Grousset4,
- E Mayer5,
- J-M Annoni5,
- A de Ribaupierre2
- 1Division of Nuclear Medicine, Geneva University Hospital, Geneva, Switzerland
- 2Faculty of Psychology and Educational Sciences, University of Geneva, Geneva, Switzerland
- 3Nutrition Unit, Geneva University Hospital, Geneva, Switzerland
- 4Hopital Font-Pre, Toulon, France
- 5Neurology Clinic, Geneva University Hospital, Geneva, Switzerland
- Correspondence to: D O Slosman Geneva University Hospital, Division of Nuclear Medicine, Geneva, Switzerland;
- Accepted 28 April 2003
Objectives: To explore relationships between scuba diving activity, brain, and behaviour, and more specifically between global cerebral blood flow (CBF) or cognitive performance and total, annual, or last 6 months’ frequencies, for standard dives or dives performed below 40 m, in cold water or warm sea geographical environments.
Methods: A prospective cohort study was used to examine divers from diving clubs around Lac Léman and Geneva University Hospital. The subjects were 215 healthy recreational divers (diving with self-contained underwater breathing apparatus). Main outcome measures were: measurement of global CBF by 133Xe SPECT (single photon emission computed tomography); psychometric and neuropsychological tests to assess perceptual-motor abilities, spatial discrimination, attentional resources, executive functioning, and memory; evaluation of scuba diving activity by questionnaire focusing on number and maximum depth of dives and geographical site of the diving activity (cold water v warm water); and body composition analyses (BMI).
Results: (1) A negative influence of depth of dives on CBF and its combined effect with BMI and age was found. (2) A specific diving environment (more than 80% of dives in lakes) had a negative effect on CBF. (3) Depth and number of dives had a negative influence on cognitive performance (speed, flexibility and inhibition processing in attentional tasks). (4) A negative effect of a specific diving environment on cognitive performance (flexibility and inhibition components) was found.
Conclusions: Scuba diving may have long-term negative neurofunctional effects when performed in extreme conditions, namely cold water, with more than 100 dives per year, and maximal depth below 40 m.
- CBF, cerebral blood flow
- DCS, decompression sickness
- SPECT, single photon emission computed tomography
Conflict of interest: none declared.