Critical fusion flicker frequency results with 1 or 2 diodes during HBOT session — observational study among hyperbaric attendants

Hyperbaric oxygen therapy (HBOT) is used as a treatment for acute and chronic diseases. The therapy is conducted in hyperbaric chambers. Hyperbaric medicine centers' use of multiplace chambers assures the patients' safety and comfort due to attendant's presence during each session. Among the patients and in the group of medical attendants the most common side effect of HBOT is middle ear disorder. However, inert gas narcosis occurring during compression to over 2 ATA (10 meters' of sea water equivalent) can be manifested in temporary cognitive function impairment, mostly due to nitrogen narcosis. One easily accessible and non-invasive method to assess cognitive functions is critical flicker fusion frequency test (CFFF). In our study, medical attendants were asked to perform CFFF with one and two diodes during separate HBOT sessions. No correlation was found between CFFF scores and the number of flickering lights. However, we observed a relationship between the CFFF results and the different times of day the task was performed. The fusion threshold decreased with age.