Seizures in Alzheimer disease: who, when, and how common?

BACKGROUND: Transient symptoms in Alzheimer disease (AD) are frequent and include seizures, syncope, and episodes of inattention or confusion. The incidence of seizures in AD and predictors of which patients with AD might be more predisposed to them is based primarily on retrospective studies and is not well established. OBJECTIVE: To determine the incidence and predictors of new-onset unprovoked seizures. DESIGN: Prospective cohort study. SETTING: Three academic centers. Patients Four hundred fifty-three patients with probable AD observed prospectively from mild disease stages since 1992. Main Outcome Measure Informant interviews every 6 months included questions about whether the patient had a seizure (convulsion, fainting, or "funny" spell) and whether diagnosis or treatment for epilepsy or seizure was made. Two epileptologists independently retrospectively reviewed all available medical records for 52 patients with positive responses to either of these questions, and using a specific checklist form, events were diagnosed as to whether they were unprovoked seizures (intrarater concordance, kappa = 0.67). Diagnosis of unprovoked seizures constituted the event in survival analyses. Potential predictors included sex, age, race/ethnicity, educational achievement, duration of illness, baseline cognition and function, depression, medical comorbidities, and time-dependent use of cholinesterase inhibitors and neuroleptic agents, apolipoprotein E genotype, and previous electroencephalographic findings. RESULTS: Over the course of 3518 visit-assessments (per patient: mean, 7.8; maximum, 27), 7 patients (1.5%) developed seizures. Younger age was associated with higher risk (hazard ratio, 1.23; 95% confidence interval, 1.08-1.41; P = .003 for each additional year of age) of seizure incidence. No other predictor was significant. The overall incidence of seizures was low (418 per 100 000 person-years of observation) although significantly higher than expected for idiopathic unprovoked seizures in similar age ranges of the general population (hazard ratio, 8.06; 95% confidence interval, 3.23-16.61). CONCLUSIONS: Unprovoked seizures are uncommon in AD, but they do occur more frequently than in the general population. Younger age is a risk factor for seizures in AD.

Seizure remission and relapse in adults with intractable epilepsy: a cohort study.

PURPOSE: To investigate the cumulative probabilities of >or=12 month seizure remission and seizure relapse following remission, and to test the associations of clinical characteristics with these two study end points in a prevalence cohort of intractable adult epilepsy patients during medical management. METHODS: A retrospective cohort study of intractable epilepsy patients seen in 2001 at a single center was conducted. Kaplan-Meier analysis was used to estimate the cumulative probabilities of seizure remission and subsequent seizure relapse. Cox proportional hazards models were used to estimate the association (1) between clinical factors and >or=12 month seizure remission and (2) between clinical factors and seizure relapse following remission. RESULTS: One hundred eighty-seven subjects met the eligibility criteria for intractable epilepsy. The estimate of probability of remission was about 4% per year. Seizure remission was temporary for some individuals, as 5 out of 20 subjects with remission ultimately relapsed. No clinical factors predicted the likelihood of achieving >or=12 month seizure remission or subsequent seizure relapse. DISCUSSION: Some people with intractable epilepsy achieve >or=12 month seizure remission during medical treatment. Remission, however, is only temporary for some individuals. We were unable to identify clear predictors for remission.