Acephalgic migraine is a term used interchangeably with the term migraine equivalents. These terms by definition refer to any migrainous phenomena that may occur in the absence of a migraine headache.1 Perhaps 20% of migraineurs may experience acephalgic attacks of migraine at one time or another. The idea that various symptoms can occur in the absence of any headache has been noted for hundreds of years, but very little has been written about this condition recently. Some people do not believe the symptoms that are often classified as migraine equivalents are in actuality part of the migraine syndrome. Because there is as yet no specific test for migraine, there is no proof that these various symptoms are due to the same neurovascular dysfunction we know as migraine. The diagnosis of migraine is based only on the patient's history and the exclusion of other diagnoses. It is not unusual for a headache patient to see several headache “specialists” and be given different diagnoses.
Some prefer the term “migraine accompaniments” for neurological or visual symptoms occurring with or without a headache.2 The aura of the classic migraine attack may linger into the painful phase and thus “accompany” rather than just precede the headache. At times, symptoms typical of the aura may occur and may not be followed by a headache (acephalgic migraine). The term “complicated migraine”should probably be reserved for those neural and/or visual symptoms that outlast the headache by at least 24 hours and should not be used when referring to symptoms of shorter duration which may accompany the headache or which occur in the absence of migraine headache. Although non-visual migraine equivalents are not nearly as common as visual symptoms, it is important to recognize the fact that migraine may account for almost any recurrent, transient, episodic organ dysfunction.