A migraine experienced without the presence of pain is considered a silent migraine, according to WebMD. A migraine exhibits any of four separate phases: prodrome, aura, pain and resolution. Mood ranges from irritability to euphoria also sometimes occur at the onset of a silent migraine.
A silent migraine is a neurovascular event in which nerves are adversely stimulated and affect the flow of blood through vessels in the brain, states WebMD. A headache is not felt during a silent migraine, but other physical symptoms of fatigue, nausea or chills are experienced. The aura phase displays neurological and sensory symptoms such as blurry vision, speech difficulties and hearing disturbances.