What can vary among individuals when experiencing CNS oxygen toxicity?

CNS oxygen toxicity refers to the effects on the central nervous system when exposed to high levels of oxygen, especially under pressure. One of the notable aspects of CNS oxygen toxicity is that precursor symptoms can vary significantly from person to person. These symptoms, which can include visual disturbances, alterations in consciousness, and twitching, do not present in a uniform manner across all divers.

Individual physiology, health status, and even psychological factors can influence how someone experiences these symptoms. This variability means that while some divers may experience early warning signs of CNS toxicity at lower partial pressures of oxygen, others may not show symptoms until they are at higher levels of exposure. This underscores the importance of recognizing and responding to any deviations from normal behavior or sensations during a dive.

As for the other options, duration of exposure typically relates to the severity of toxicity but is not individually variable; it’s more a function of the environmental conditions and gas mixture. Balancing factors may refer to multiple influences on diving safety but lack the personal variability aspect that precursor symptoms do. Air pressure changes are generally uniform but affect all divers similarly, making them less relevant to the individual variability in symptoms of CNS toxicity.