Epileptic Vertigo and related conditions
Timothy C. Hain, MD Page last modified: August 30, 2015
The following list of conditions will be briefly reviewed:
While epilepsy is commonly accompanied by dizziness or vertigo, vertigo is only rarely caused by epilepsy (Bladin 1998). This arises primarily because vertigo is much more commonly caused by ear conditions.
Epileptic vertigo is felt to be cause by abnormal stimulation of parts of the cortex that represent the vestibular system -- parietal, temporal and frontal cortex. Specific areas include the superior lip of the intraparietal sulcus, the posterior superior temporal lobe, the postero-medial parietal lobe (Wiest et al, 2004), the temporal parietal border regions (Penfield, 1954; Blanke et al 2000; Kahane et al, 2003), V5 (Laff et al. 2003), and frontal cortex -- left middle frontal gyrus (Kluge et al, 2000). As of 2015, about 84 studies including 11,354 patients were reported (Tarnutzer et al, 2015)
A related phenomenon is "reflex epilepsy" (Xue et al, 2006). These are epileptic seizures precpiated by general sensory stimuli - -such as light, thinking, decision making. The "focal" reflex epilepsies may be provoked by reading, writing, startle, somatosensory stimulation, proprioception, auditory stimuli, immersion in hot water, eating, and vestibular stimulation. Thus, certain sounds or types of movement can provoke cortical seizures.
Another electrical disorder, which can overlap with these possibilities, is vestibular neuralgia. Although a misnomer (algia means pain and there is no pain here), this is a condition in which the vestibular nerve becomes irritable and spontaneously produces an abnormal sensation of movement. There is very little known about vestibular neuralgia. In some instances, it may be caused by microvascular compression syndrome. It is sometimes called "vestibular paroxysmia", which is a more vague but somewhat more appropriate term.
Rarely, epilepsy is accompanied by tinnitus. Stimulation of human auditory cortex can suppress hearing or enhance tinnitus (Fenoy et al, 2006). In persons who have bilateral synchronous hearing symptoms, clinicians usually consider electrical or vascular cortical phenomena such as migraine aura as the cause.
Epileptic vertigo is generally only a diagnostic problem when the person does not have a full seizure -- in other words, they do not have the convulsions, psychomotor symptoms or twitching characteristic of classic partial or generalized seizures. According to Tarnutzer et al (2015) vertigo without a seizure -- isolated "EVD" is about 10 times less common than non-isolated EVD.
In most instances, it presents as a "quick spin" type symptom. The person notes that the world makes a quick horizontal movement, lasting roughly 1-2 seconds at most. Quick spins must be differentiated from a variety of other conditions including vestibular neuralgia due to microvascular compression, Meniere's syndrome, and BPPV among others. Occasional people also develop this symptom who have ectatic basilar arteries.
Rapidly generalized seizures are generally incompatible with epileptic vertigo as persons with generalized seizures will not remember their aura.
Reflex vestibular epilepsy can be difficult to diagnose as most EEG labs are unable to provide vestibular stimulation during their recordings. This can be accomplished in a lab equipped for both caloric and EEG testing.
Diagnostic tests that are particularly helpful include the EEG and MRI scan of the head. In essence when these tests are normal, a response to an anticonvulsant medication is suggestive of vestibular neuralgia. When the EEG is definitely abnormal, vestibular epilepsy is diagnosed. One must be cautious here as many otherwise normal persons have mildly abnormal EEG tests. When there is no response to medication, then the probability of one of the other disorders mentioned above is increased.
Epileptic and neuralgic vertigo generally responds well to traditional anticonvulsants such as oxcarbamazine and related medications. Oxcarbamazine also treats vestibular paroxysmia. According to Xue, generalized reflex seizures usually respond to valproate treatment (Xue, 2006). Valproate also treats migraine.
In the case illustrated below, a child became dizzy, developed nystagmus, and briefly became unresponsive.
|EEG of child with a vestibular seizure. On the bottom right the electrical activity of the brain changes markedly (Tusa et al, 1990).|