Abstracts

Rationale: The distribution of the underlying causes of epilepsy is expected to differ between the young and the old. Epilepsy is therefore expected to behave differently in older individuals. The purpose of this study was to compare the characteristics of epilepsy in older adults to those of younger adults referred to a tertiary care centre. Methods: We used the prospective comprehensive Calgary Epilepsy Programme database to identify all consecutive first presentations to the clinic. Standardised forms are used to collect patient data at first presentation. Information pertaining to demographics, seizure characteristics, investigations, and treatment was collated. We defined older individuals with epilepsy as those whose date of first seizure occurred at age 65 or above. We used the χ² test for comparisons of categorical variables. Parametric statistics were used for continuous variables with approximately normal distributions and non-parametric statistics were used for those without normal distributions. We used a two-tailed alpha level of significance of 0.05. Results: We identified 2159 patients of whom 130 (6.0%) had their first seizure at age 65 and over. A lower proportion of older adults were seizure-free over the year prior to the clinic visit (10% versus 28%; p=0.02). The percentage of people reporting auras was lower for older individuals (33% versus 47%; p=0.003), as was the percentage reporting focal non-dyscognitive seizures (13% versus 22%; p=0.02), or generalised tonic-clonic seizures (54% versus 69%; p<0.001). Fewer older adults had post-ictal confusion or aggression (54% versus 68%; p<0.001). Older adults also had differing risk factor profiles. They were more likely to have had a stroke (25% versus 4%; p<0.001) and an abnormal neurological exam (50% versus 24%; p<0.001); they were less likely to have had birth trauma (1% versus 6%; p=0.01), febrile convulsions (1% versus 7%; p=0.01), a developmental disorder (2% versus 12%; p=0.004), and a family history of epilepsy (9% versus 23%; p<0.001). Older adults with epilepsy were less likely to have common seizure triggers such as sleep deprivation (11% versus 38%; p<0.001), alcohol (4% versus 13%; p=0.004), flashing lights (2% versus 11%; p=0.001), and stress (14% versus 43%; p<0.001). Approaches to treatment also differed; a greater proportion of older adults were taking phenytoin (25% versus 14%; p=0.001) or levetiracetam (21% versus 14%; p=0.03) while fewer were on carbamazepine (9% versus 16%; p=0.04) and lamotrigine (2% versus 10%; p=0.004). Referral for psychiatric assessment was less common in older adults with epilepsy (3% versus 12%; p=0.001). Conclusions: This preliminary analysis indicates that older adult onset epilepsy appears to represent a unique entity. Interestingly, 1-year seizure remission, treatment strategies, and psychiatric co-morbidities differ significantly from those in the young. The emphasis should now be on defining optimal diagnostic and treatment strategies for those aged 65 and older at the time of seizure onset. Our proposed next step is to model variables associated with seizure freedom in both the young and the elderly.