A 10-year follow-up of patients with transient epileptic amnesia (TEA) found that life expectancy is not reduced and that seizures were generally controlled with medication. These findings were published in the journal Epilepsia.
TEA is an adult-onset form of epilepsy associated with brief episodes of amnesia with the absence of other cognitive impairments. Since 1998, about 250 cases have been reported. Although diagnostic features have been well-established, long-term outcomes remain poorly understood. To evaluate long-term outcomes, the medical records of 47 patients with TEA who enrolled in The Impairment of Memory in Epilepsy (TIME) study in 2004-2005 were reevaluated for clinical outcomes and mortality.
Among this study population, TEA onset at 62.3 years, 68.1% were men, 46.8% had seizures after enrolling in TIME, 78.7% had vascular disorders, 25.5% autoimmune disorders, 14.9% dementia, and 21.3% depression.
A total of 21 of the patients had died during follow-up. The cohort of individuals who were deceased were older at TEA onset (mean, 65.4 vs 59.7 years; P =.03), older at study enrollment (mean, 73.2 vs 64.8 years; P <.01), and more had dementia (28.6% vs 3.8%; P =.02). There was no evidence the cohort of patients who did not survive had more seizures.
The average age at death among the TEA cohort was 82.5 years, which was higher than the national average in the UK (mean, 81.3 years).
About half of participants remained on the same medication and dosage without experiencing additional seizure during the 10-year follow-up. There were 10 individuals who had a reemergence of seizure, 6 of whom had a reemergence after a long period of stability. One patient chose to cease medication and experienced 2 to 3 episodes of TEA yearly.
The most common therapy was monotherapy with carbamazepine (n=12), lamotrigine (n=9), sodium valproate (n=6), levetiracetam (n=6), and phenytoin (n=3). Two patients took sodium valproate plus lamotrigine and one carbamazepine, phenytoin, and levetiracetam.
Compared with the general population, the TEA cohort was not associated with an increased prevalence in stroke, hypertension, or ischemic heart disease. The rate of atrial fibrillation was 8.5% among the TEA cohort compared with rates of 6% among those aged 65-74 years, 14% among those aged 75-84 years, and 22% for those aged 85 years or older.
The rate of dementia was 14.9% among the TEA cohort which was higher than the general population rate among those aged 80-84 years (11.1%) but lower than the rate for those aged 85-89 years (18.3%). The TEA cohort was associated with a higher prevalence of lifetime depression compared with the general population (21.3% vs 19.7%).
This study was limited by its modest sample size, however, given the rarity of the condition, the researchers were unable to reach their target sample size of 50.
“Consistent with our smaller study in nine cases, the current results confirm within a larger group that life expectancy does not appear to be reduced, as compared with current population averages within the UK provided by the Office for National Statistics,” the researchers stated.
Savage SA, Baker J, Milton F, Butler C, Zeman A. Clinical outcomes in transient epileptic amnesia: A 10-year follow-up cohort study of 47 cases. Epilepsia. Published online March 6, 2022. doi:10.1111/epi.17214