When headache has a recent onset, it presents suddenly, and it is triggered by strain, even with normal neurological examination, neuroimaging is mandatory in order to exclude secondary headaches, especially in children.
When headache has a recent onset, it presents suddenly, it is triggered by strain, even with normal neurological examination, neuroimaging is mandatory in order to exclude secondary headaches, particularly in children.
However, all of these experiments utilize suddenly onsetting stimuli to measure endogenous and exogenous attention alike and, thus, are still somewhat confounded.
This issue arises in designs attempting to assess the physiological effects of endogenous attention using paradigms in which suddenly onsetting stimuli appear in either a cued (and hence attended) or uncued (unattended) location in space.
While ERP studies of endogenous attention have been widely reported, these experiments have a serious limitation in that the suddenly onsetting stimuli, used to elicit the ERP, inevitably have an exogenous, attention-grabbing effect.
Environmental changes can occur suddenly (fast-onset changes) in the form of a flood, hurricane, tsunami, or earthquake, or they can occur gradually (slow-onset changes), for example in the case of climate change, land degradation, and rising sea level.
In his Memoirs Gibbon remarked that with the onset of puberty his health suddenly improved and remained excellent throughout his life.
In the perturbed demonstrations, the target's location is changed suddenly after the onset of the motion.
The onset of symptoms can occur suddenly and can rapidly progress, potentially becoming fatal within hours.
