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Updated: Feb 19, 2026
Training Rats to Voluntarily Dive Underwater: Investigations of the Mammalian Diving Response
Published on: November 12, 2014
Repetitive freshwater diving: risk factors and prevalence of barotrauma
Stefanie Jansen1, Moritz Friedo Meyer1, Manuela Boor1
1Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Germany.
Objective:
The aim was to investigate the influence of repetitive scuba diving in fresh water on the middle ear mucosa. The prevalence of middle ear barotrauma (MEB) and risk factors for MEB were evaluated.
Study Design:
Prospective cohort study, Level of evidence 1b.
Methods:
During three days, 23 divers made 144 repetitive dives in a freshwater lake. Participants underwent otoscopic examinations and were questioned about ENT-related complaints in the morning before the first dive, in between the dives and after the last dive. Otoscopic findings were documented and classified according to the TEED scale (0 = normal eardrum to 4 = perforation), for the right and the left ear separately.
Results:
In total, 416 examinations were performed. ENT-related complaints during diving, mostly failed pressure equalization (74%), were reported after 10% of all dives. Most common pathology was MEB (TEED 1-3, 26%). Valsalva maneuver was possible during all exams. Significant increase of MEB (TEED⟩0) occurred with an increasing cumulative number of dives per day (P ⟨ .0001). Diving depth significantly influenced the MEB distribution (P = .035). MEB with higher TEED levels (2 and 3) was present only in the less experienced and intermediate divers. With increasing TEED level, more participants reported ENT-related problems (P ⟨ .0001). However, 74.4% of divers with MEB were still asymptomatic.
Conclusion:
During three days of diving, the MEB prevalence increased with a cumulative number of dives per day. The major risk factors were diving depth and diving experience. Higher TEED level correlated with an increasing number of subjective ENT-related disorders during diving.
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