True or False: Signs and symptoms can appear suddenly before a CNS convulsion.

Signs and symptoms can indeed present suddenly before a central nervous system (CNS) convulsion, making this dichotomy important for divers to recognize. In scenarios related to CNS issues, particularly those involving diving, symptoms such as disorientation, confusion, dizziness, or even visual disturbances might occur without ample warning, contributing to unexpected convulsions.

For divers, being aware of the sudden onset of these signs is crucial for safety, as recognizing them early can lead to prompt actions and necessary interventions. Understanding that these symptoms can manifest quickly helps divers to remain vigilant and prepared while diving, ensuring they can respond appropriately if they notice someone exhibiting these signs.

Additionally, the other options do not accurately reflect the nature of CNS convulsions or the awareness required by divers. For instance, the suggestion that it depends on diver experience does not capture the unpredictable nature of symptoms that can occur irrespective of prior training. Similarly, the notion that signs will always be visible misrepresents the potentially subtle or abrupt nature of the signs preceding a convulsion. Therefore, acknowledging the possibility of sudden signs phenomenological is essential for the safety of divers.