There is currently a debate within the medical community regarding the precise definition of epilepsy. In the past, it was accepted that a person should not be diagnosed as having epilepsy until that individual had two or more seizures. However, with current diagnostic tools, brain pathology can be readily identified, and studies have shown that persons with certain conditions, such as stroke or brain tumor, have a high probability of having more seizures after a single seizure. As a result, many epileptologists, including prominent members of the ILAE (International League Against Epilepsy), are proposing that epilepsy be defined as a condition of the central nervous system predisposing to seizures. Thus, a single seizure associated with specific pathology would be sufficient to initiate treatment to prevent further seizures. This is of particular importance to the geriatrician because many persons with seizures in this age group have identifiable brain pathology.
Seizure classification is based on the functional anatomy of the brain. The smallest seizures are termed simple partial seizures. These do not involve loss of consciousness, and the manifestation of the seizure reflects the function of the area of brain from which these originate. Thus, clonic activity of the right hand (minor motor seizure) originates from an epileptogenic zone in the left motor cortex. Simple partial seizures can be motor, sensory, visual, olfactory, or psychic (de ja vue; brief panic). Because patients are alert during these seizures, they are able to remember what happened. This history can be of great value in localizing the area of brain from which the seizures originated. Complex partial seizures usually originate from the temporal lobes. During the seizure, a person will perform automatic activities such as lip smacking, unbuttoning, wandering aimlessly, or other semipurposeful behaviors. Because memory is mediated by the temporal lobes, persons have no memory for the event. A simple partial seizure can evolve into a complex partial seizure, and both can excite the whole brain and evolve into a generalized tonic-clonic seizure (convulsion; “Grand Mal”). Persons with these seizures are described as having localization-related epilepsy, and most elderly have this type of epilepsy.
Incidence in Community-Dwelling Elderly
Until a few decades ago, epilepsy was mostly a disorder of children. However, as the population of persons older than 65 years has increased, the demographics have changed dramatically. The incidence of epilepsy (new cases per 100,000) in the United States and developed countries now forms a U-shaped curve (Figure 69-1). The incidence of epilepsy is higher in the elderly than in any other age group and rises with each decade after the age of 55 years. Because of the rapid growth in their numbers and their propensity to develop epilepsy, elderly persons will represent an increasingly large group of patients needing expert care for this disorder. In the United States, approximately 181,000 persons developed epilepsy in 1995, and approximately 68,000 of these were older than 65 years. Similar high ...