Abstracts

Identification and treatment of subtle seizure types can be difficult in elderly subjects. Tonic clonic seizures are easy to identify but subtle, complex or simple partial seizures (CPS, SPS) or epilepsy partialis continua (EPC) may be difficult to identify. These subtle, repetitive seizures may require prolonged EEG to diagnose which can be facilitated with computerized video EEG systems (CVEEG). CVEEG can identify such subtle seizure types. We have identified a group of seizures in geriatrics that we refer to as subtle, repetitive seizures (SRS), as they share features of EPC, SPS and CPS. These seizures may not be readily identified as ictal behavior without CVEEG confirmation. Use of CVEEG suggests that subtle, repetitive seizures are under-recognized in hospitalized geriatrics. Incidence of this seizure type and clinical characteristics will be described
An EEG laboratory database was reviewed to identify hospitalized subjects greater than 60 years of age who were evaluated for seizures over a 4 month interval. EEGs and clinical information were reviewed to identify subjects with seizures. Among those with seizures during the EEG, clinical descriptions and video and EEG characteristics of the seizures were reviewed to determine the seizure type.
In this time period, 170 elderly subjects underwent CVEEG. In this group, 32 had epileptiform activity including 3 with post-anoxic patterns. PLEDS or frequent spikes were seen in 2 individuals with recent status epilepticus. Seizures occurred during an EEG for 5; in 4 cases seizures were repetitive. In this group there were 3 individuals who were awake, but confused with subtle, repetitive seizure activity including movements of face, hand or leg. Subjects with SRS had some seizures with simultaneous epileptiform activity and motor activity, but in prolonged recording had similar motor activity without clear scalp EEG correlate. The awake SRS had occipital or parietal MRI abnormalities. Only one SRS subject had pre-existing epilepsy. One had acute metabolic derangements in association with chronic occipital ischemia. One had an acute occipital infarct. All SRS had prolonged ictal symptoms, in 3/4 cases, refractory to treatment. In addition to these 4 cases, there were 2 additional subjects within the group of 32 who had occipital ischemia and similar behaviors which resolved prior to the EEG.
Among hospitalized geriatrics referred for an EEG, subtle seizures are not uncommon. Clinical characterization of these types of seizures as well as quantification is facilitated by CVEEG. CVEEG may be valuable for elderly subjects with alteration of mental status and sharp waves or seizures on a routine EEG. Acute neurologic insult, particularly involving the posterior cortex or metabolic derangement predisposes to this syndrome. Geriatrics with a single seizure on a routine EEG should be considered for a prolonged recording because of the high probability of recurrence in the acute setting.