Prospective study of seizures in the elderly in the Marshfield Epidemiologic Study Area (MESA).

PURPOSE: To assess the incidence, etiology, antiepileptic drug (AED) use, and quality of life in patients having their first seizure at age 50 years or older. METHODS: All patients in the Marshfield Epidemiologic Study Area (MESA) aged 50 years or older having their first seizure between July 1, 1996, and June 30, 1998, were identified through the diagnostic coding system. Patients were followed up for 12 months for recurrent seizures. Etiologies, drug treatments, magnetic resonance imaging (MRI), computed tomography (CT), or EEG results and medication adverse effects were recorded. Those patients who reached 1-year follow-up received a quality of life (QOLIE-31) survey. RESULTS: Forty-eight patients having a first seizure were identified (162 of 100,000). Twelve patients had had recurrent seizures, and 36 had a single seizure at the time of study entry. Fourteen of these 36 had had an abnormal MRI, CT, or EEG. The remaining 22 had a single seizure and normal imaging and EEG. Six of these had one or more subsequent seizures, and all six were in the group with normal tests. Etiologies included vascular, neoplasm, trauma, dementia, metabolic, and unknown. Seventy-five percent of the patients achieved seizure control with phenytoin, carbamazepine, and/or valproate. Twenty-seven percent experienced adverse side effects. None had been given second-generation AEDs as an initial treatment. Thirty-one patients received the QOLIE-31 survey; 20 did not complete the survey for various reasons. The mean QOLIE-31 scores for those completing the survey were significantly higher than those of the reference cohort. CONCLUSIONS: The incidence of first seizure in MESA is high in the elderly and increases with advancing age. As in other studies, vascular causes accounted for the largest etiology. Use of new AEDs was uncommon. There was a high incidence of untoward side effects related to the traditional AEDs. High morbidity and mortality unrelated to seizures limits follow-up analysis in the elderly. Quality-of-life analysis via QOLIE questionnaires is problematic in this population.

Transient trochlear nerve palsy following anterior temporal lobectomy for epilepsy.

Three of 22 patients (14%) who underwent anterior temporal lobectomy for treatment of medically intractable epilepsy at our institution from July 1987 through July 1993 experienced diplopia immediately after surgery. We found ipsilateral paresis of the superior oblique muscle in all three patients. Their ophthalmoplegia resolved completely within 14 weeks. We did not observe any new structural or ischemic changes on postoperative MRIs to account for their deficits. Trochlear nerve palsy--not oculomotor nerve palsy, as is reported in most reference texts--is a relatively common cause of transient diplopia following temporal lobectomy. Indirect (ie, traction) injury of the trochlear nerve is a plausible mechanism that would explain this complication.

Seizure exacerbation and status epilepticus related to carbamazepine-10,11-epoxide.

Over a 3-year period, we encountered 6 adults whose seizure control unexpectedly deteriorated with the occurrence of partial status epilepticus and daily multiple seizures. Analysis of the case histories and subsequent clinical follow-up for 1 1/2 to 3 years disclosed the following evidence that demonstrates the role of carbamazepine-epoxide in the development of the seizure exacerbation: (1) There were high serum carbamazepine-epoxide concentrations while serum carbamazepine concentrations were lower than or the same as baseline levels; (2) all patients were taking drugs that are known to increase serum carbamazepine-epoxide concentrations; (3) status epilepticus failed to respond to intravenous phenytoin loading; (4) seizure exacerbation in all patients was corrected by withholding carbamazepine dose; (5) seizure exacerbation recurred in 1 patient who resumed the same dose of carbamazepine; and (6) there were no prior status epilepticus or daily multiple seizures despite previous toxicities with other antiepileptic drugs in 3 patients. Our experience shows that inconspicuous elevation of carbamazepine-epoxide levels during polytherapy may precipitate a distinct state of drug toxicity characterized by severe exacerbation of seizures. Mental retardation may be a predisposition to this condition.

Yield of sphenoidal recording in sleep-deprived outpatients.

We retrospectively reviewed the results of sphenoidal recordings performed after sleep deprivation in 101 consecutive outpatients whose prior scalp EEGs failed to show epileptiform discharges (EDs). These patients were suspected of having seizures of temporal lobe origin. Blinded reviews of the recordings by two electroencephalographers showed a tendency for sphenoidal recording to detect EDs at a higher rate than scalp recording, but the difference did not reach statistical significance (p = 0.06). However, EDs appeared exclusively at sphenoidal electrodes in 11 patients and exclusively at scalp electrodes in 3. The probability of detecting EDs with combined scalp and sphenoidal recordings was greater when spells were characterized by focal symptoms or signs. Except in three patients, initial EDs occurred during the first 30 min of recording. We recommend that post-sleep-deprivation recording be performed initially with scalp and other noninvasive electrodes (such as anterior temporal, ear, or cheek electrodes). If no EDs occur after 30 min, sphenoidal electrode insertion and recording may then be considered, especially in patients with spells characterized by focal signs or symptoms.

Prognosis of photoparoxysmal response in nonepileptic patients.

Photoparoxysmal response (PPR) is sometimes incidentally encountered in EEGs performed for evaluation of nonepileptic symptoms. We conducted the first long-term study of a cohort of nonepileptic patients to determine their risk of having seizures subsequent to incidental recording of PPR. After 6 to 12 years (mean, 9 years), none of the 33 patients had had epileptic seizures. To identify prognostic factors associated with PPR, we performed a case-control study comparing the cohort with 33 age-matched patients who had had epileptic seizures prior to PPR recording. There was no statistically significant difference between the two groups with respect to the clinical or EEG data. Morphology of the PPR discharge was not different between the two groups. Contrary to what is widely believed, persistence of PPR discharges beyond stimulation was not associated with a high risk of developing seizures. Prognosis of PPR is age-dependent and seems favorable in adults without previous epileptic seizures.