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Summary: Purpose: Epilepsy is a common problem in institutionalized patients with multiple handicaps. Limited data exist on the characteristics of epilepsy in this patient population and the impact of systematic evaluation by an epilepsy service.
Methods: We evaluated 138 patients with epilepsy, institutionalized at a facility that cares for 324 patients with multiple handicaps. Evaluation included EEG, MRI, and video-EEG monitoring. The medication regimen was changed according to seizure diagnosis and the status of seizure control. Follow-up was available for ≥6 months in 110 patients, 1 year for 89, and 1.5 years for 49 patients. We analyzed the seizure and epilepsy diagnosis in this population, as well as the seizure frequency after evaluation and treatment
Results: The 76 male and 62 female patients' ages ranged from 14 to 73 years. Seventy-three patients had fewer than one seizure per month, whereas 29 patients had at least one seizure per month. Of 131 patients taking antiepileptic drugs (AEDs), 62 were receiving monotherapy, and 69 were receiving two or more AEDs. At the last follow-up, overall 55% of patients had reduced seizure frequency, including 23% who became seizure free. Two of 36 patients had spontaneous seizure recurrence after being seizure free with no AEDs for 4 months in one patient and 3 years for the other. Attempts were made to discontinue phenobarbital, primidone, and clonazepam in 21 patients. However, these were discontinued in only five patients.
Conclusions: Epilepsy is heterogeneous in institutionalized patients with multiple handicaps. It is often responsive to medical therapy. Evaluation and treatment by epilepsy specialists had an overall favorable impact on seizure control.
A significant association between epilepsy and mental retardation (MR) has been documented (Corbett, 1989), although the estimated prevalence of epilepsy in individuals with MR is dependent on the survey method (Bowley and Kerr, 2000). In community-based studies, the prevalence rate was reported as 20% (Corbett JA, 1989). In an institutionalized patient survey, the prevalence was ∼32.0% (Mariani E et al., 1993). In one community-based study, the incidence was higher in patients with cerebral palsy, affecting ∼50% of these patients and 21% of those without cerebral palsy, when followed up to age 7 years (Van den Berg and Yerushalmy, 1969). MR and/or cerebral palsy represent the second most common antecedents of epilepsy, observed in 8% of cases (Hauser et al., 1993). The epilepsy in patients with MR is considered to be refractory to antiepileptic drugs (AEDs) in most cases (Pellock and Hunt, 1996). These patients are often treated with AEDs for life and are often maintained on polypharmacy. Reluctance to discontinue medications or make changes is often due to fear of precipitating status epilepticus or unacceptable behavior (Pellock and Hunt, 1996).
Few studies have classified and characterized seizures and epilepsy in this population or evaluated simplifying or tapering of AEDs. We have used the opportunity of a seizure clinic started at an institution for individuals with multiple handicaps for a better understanding of epilepsy and its treatment in this population. This study was specifically undertaken to evaluate a large institutionalized population with MR and epilepsy, to classify seizures and epilepsy in this population, to evaluate the responsiveness of epilepsy to medical therapy, and to assess the potential for simplifying AED regimens and, in some instances, complete discontinuation of AEDs.
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This study was conducted to evaluate the impact of an epileptology clinic at an institution that cares for patients with MR and epilepsy. We included all patients with a diagnosis of epilepsy, including those not taking AEDs (all were referred to the epileptology clinic). Seizure control was improved in 55% of patients. The key specific changes that occurred after implementation of this clinic were improved classification of seizures and epilepsies and subsequent medication adjustments, including initiation of new drugs, reduction of polypharmacy, and discontinuation of sedating AEDs.
The seizure and epilepsy classifications were corrected in 36.5% of our patients, with the help of video-EEG monitoring in many patients. Classification is important in seizure management. Many patients with MR have abnormal behavior episodes that may resemble epileptic seizures but that are not epileptic in origin (Crews et al., 1994). Pseudoseizures, movement disorders, breathholding spells, gastroesophageal reflux, sudden aggression, and self abuse are some of examples of such behavior, which can mimic epilepsy in these patients. Video-EEG monitoring enables any behavior to be analyzed in relation to the EEG changes and has proven to be an excellent tool to distinguish between epileptic seizures and nonepileptic spells and to classify seizures (Porter et al., 1976), Sutula et al., 1981). We performed EEG-CCTV on 52 (38%) patients, and of those, 36 (69%) had either ictal or interictal abnormalities. Video-EEG monitoring is more often productive in this population, and short-term monitoring may be sufficient to classify frequent events (Thirumalai et al., 2001). In the institutionalized patients with MR and epilepsy, partial seizures with or without secondary generalization are reported to be more prevalent than other seizure types (Mariani et al., 1993). Other seizure types in this population are absence, generalized tonic, clonic, tonic–clonic, and myoclonic seizures. In our study, the vast majority of patients had a single seizure type, and partial seizures were more frequent than generalized seizures. Seizure type was based on the EEG, MRI, and video-EEG monitoring. Because we were unable to videotape seizure occurrences in the residential areas, it is possible that the four patients categorized as having generalized tonic seizures was an underestimate. Without recorded events, the seizure diagnosis in these patients can be difficult. The clinician has to rely on sparse history and on the account of the caretakers and nursing staff who have limited knowledge of seizures and epilepsy.
After evaluation and definitive seizure diagnosis, medication changes were made in 82 (74%) of 110 patients who returned for follow-up. One important medication change is medication discontinuation. Medication discontinuation was attempted predominantly to remove sedating drugs and alleviate polypharmacy, although it was occasionally considered for patients seizure free for many years if it was suspected that therapy was no longer needed. In our study we were able to discontinue PB, PRM, or CZP in five of 21 (24%) patients without compromising seizure control. The benefits of withdrawal of sedating AEDs are improved alertness, improved mobility, and better cognitive functioning. Conversely, discontinuation of AEDs has associated risks, including relapse or exacerbation of seizures with associated risk of injuries, status epilepticus and sudden unexpected death. Other studies have reported greater success and suggested that the treatment of many patients with epilepsy can often be best accomplished with the use of fewer drugs or monotherapy (Callaghan et al., 1984; Ferngren et al., 1991; Poindexter et al., 1993). In one study, 48% of seizure-free patients with MR and epilepsy remained seizure free after AED discontinuation, even after a follow-up period of 8 years (Alvarez, 1989). In another study, 12% of patients had an AED discontinued as part of an attempt to simplify polypharmacy, but 45% of patients who had an AED discontinued required restarting that AED over a 10-year follow-up period (Pellock and Hunt, 1996). Nevertheless, this suggests that precautions should be taken with tapering these medications in this patient group.
We found no positive correlation between seizure frequency and severity of MR. The patients with severe MR tended to have lesser seizure frequency. This is different from the current literature and may be attributable to a selection bias related to the criteria for institutionalization at the study facility. It is possible that patients with both severe MR and severe epilepsy were more likely to be in a different type of institution. We did not find any significant correlation with seizure frequency and classification of epilepsy (partial vs. generalized) or age at seizure onset.
In conclusion, epilepsy in institutionalized patients with MR can frequently be well controlled with accurate seizure diagnosis. Simplification of the medication regimen is possible, but caution and careful weighing of risks and benefits are needed during discontinuation of sedating AEDs.