Intact speech perception after resection of dominant hemisphere primary auditory cortex for the treatment of medically refractory epilepsy: illustrative case.

BACKGROUND: In classic speech network models, the primary auditory cortex is the source of auditory input to Wernicke's area in the posterior superior temporal gyrus (pSTG). Because resection of the primary auditory cortex in the dominant hemisphere removes inputs to the pSTG, there is a risk of speech impairment. However, recent research has shown the existence of other, nonprimary auditory cortex inputs to the pSTG, potentially reducing the risk of primary auditory cortex resection in the dominant hemisphere. OBSERVATIONS: Here, the authors present a clinical case of a woman with severe medically refractory epilepsy with a lesional epileptic focus in the left (dominant) Heschl's gyrus. Analysis of neural responses to speech stimuli was consistent with primary auditory cortex localization to Heschl's gyrus. Although the primary auditory cortex was within the proposed resection margins, she underwent lesionectomy with total resection of Heschl's gyrus. Postoperatively, she had no speech deficits and her seizures were fully controlled. LESSONS: While resection of the dominant hemisphere Heschl's gyrus/primary auditory cortex warrants caution, this case illustrates the ability to resect the primary auditory cortex without speech impairment and supports recent models of multiple parallel inputs to the pSTG.

Prevalence of self-reported epilepsy in a multiracial and multiethnic community in New York City.

PURPOSE: To estimate the prevalence of epilepsy in a racially and ethnically diverse neighborhood in New York City. METHODS: We used random-digit dialing to identify people with a history of epilepsy. We estimated the prevalence of active epilepsy and lifetime epilepsy. RESULTS: The age-adjusted prevalence of active epilepsy was 5.0 per 1000, and that of lifetime epilepsy was 5.9 per 1000. Prevalence appeared higher in Hispanics (active prevalence: 6.3 per 1000; lifetime prevalence: 7.5 per 1000) than in non-Hispanics (active prevalence: 4.1 per 1000; lifetime prevalence: 4.7 per 1000). Blacks appeared to have a lower prevalence of active epilepsy (5.2 per 1000) than whites (5.9 per 1000), but a higher lifetime prevalence (7.5 per 1000 vs. 5.9 per 1000). Ethnic and racial differences in access to epilepsy care were evident both in terms of drug treatment and use of emergency departments for care. CONCLUSIONS: The prevalence of epilepsy in this predominantly minority urban community is similar to that reported in other contemporary studies. Less access to health care for black and Hispanic respondents, compared with white respondents, may have influenced self-reported active epilepsy prevalence estimates since the definition includes recent use of antiseizure medication.

Rates and predictors of long-term seizure freedom after frontal lobe epilepsy surgery: a systematic review and meta-analysis.

OBJECT: Frontal lobe epilepsy (FLE) is the second-most common focal epilepsy syndrome, and seizures are medically refractory in many patients. Although various studies have examined rates and predictors of seizure freedom after resection for FLE, there is significant variability in their results due to patient diversity, and inadequate follow-up may lead to an overestimation of long-term seizure freedom. METHODS: In this paper the authors report a systematic review and meta-analysis of long-term seizure outcomes and predictors of response after resection for intractable FLE. Only studies of at least 10 patients examining seizure freedom after FLE surgery with postoperative follow-up duration of at least 48 months were included. RESULTS: Across 1199 patients in 21 studies, the overall rate of postoperative seizure freedom (Engel Class I outcome) was 45.1%. No trend in seizure outcomes across all studies was observed over time. Significant predictors of long-term seizure freedom included lesional epilepsy origin (relative risk [RR] 1.67, 95% CI 1.36-28.6), abnormal preoperative MRI (RR 1.64, 95% CI 1.32-2.08), and localized frontal resection versus more extensive lobectomy with or without an extrafrontal component (RR 1.71, 95% CI 1.26-2.43). Within lesional FLE cases, gross-total resection led to significantly improved outcome versus subtotal lesionectomy (RR 1.99, 95% CI 1.47-2.84). CONCLUSIONS: These findings suggest that FLE patients with a focal and identifiable lesion are more likely to achieve seizure freedom than those with a more poorly defined epileptic focus. While seizure freedom can be achieved in the surgical treatment of medically refractory FLE, these findings illustrate the compelling need for improved noninvasive and invasive localization techniques in FLE.

Facial emotion recognition after curative nondominant temporal lobectomy in patients with mesial temporal sclerosis.

PURPOSE: The right (nondominant) amygdala is crucial for processing facial emotion recognition (FER). Patients with temporal lobe epilepsy (TLE) associated with mesial temporal sclerosis (MTS) often incur right amygdalar damage, resulting in impaired FER if TLE onset occurred before age 6 years. Consequently, early right mesiotemporal insult has been hypothesized to impair plasticity, resulting in FER deficits, whereas damage after age 5 years results in no deficit. The authors performed this study to test this hypothesis in a uniformly seizure-free postsurgical population. METHODS: Controls (n=10), early-onset patients (n=7), and late-onset patients (n=5) were recruited. All patients had nondominant anteromedial temporal lobectomy (AMTL), Wada-confirmed left-hemisphere language dominance and memory support, MTS on both preoperative MRI and biopsy, and were Engel class I 5 years postoperatively. By using a standardized (Ekman and Friesen) human face series, subjects were asked to match the affect of one of two faces to that of a simultaneously presented target face. Target faces expressed fear, anger, or happiness. RESULTS: Statistical analysis revealed that the early-onset group had significantly impaired FER (measured by percentage of faces correct) for fear (p=0.036), whereas the FER of the late-onset group for fear was comparable to that of controls. FER for anger and happiness was comparable across all three groups. CONCLUSIONS: Despite seizure control/freedom after AMTL, early TLE onset continues to impair FER for frightened expressions (but not for angry or happy expression), whereas late TLE onset does not impair FER, with no indication that AMTL resulted in FER impairment. These results indicate that proper development of the right amygdala is necessary for optimal fear recognition, with other neural processes unable to compensate for early amygdalar damage.

Tonic-absence seizures: an underrecognized seizure type.

PURPOSE: The individual electroclinical patterns--tonic seizures with generalized paroxysmal fast activity (GPFA, activity >13 Hz), and absence seizures with generalized slow spike-and-wave activity (GSS&W, <3 Hz)--have been extensively described in the literature. However, only passing reference was made to the pattern of GPFA followed by GSS&W. In addition, these descriptions were formulated in the pre-EMU (Epilepsy Monitoring Unit) era, without benefit of video/clinical correlation. We now characterize this underrecognized seizure type. METHODS: We retrospectively reviewed the data from eight patients with seizures that demonstrated this stereotyped EEG and clinical pattern. RESULTS: We identified eight patients (six female patients; age 6-29 years; age at seizure onset, neonate to 10 years) who were evaluated at the Columbia University Epilepsy Monitoring Units between 1993 and 2002. All eight had an International League Against Epilepsy (ILAE) diagnosis of symptomatic generalized epilepsy, with six of eight manifesting multiple seizure types, six of eight with mild static encephalopathy, and two with normal cognition. A total of 29 seizures of this pattern was recorded; 26 of 29 seizures demonstrated GPFA (frequency between 14 and 30 Hz, lasting 2-8 s) followed by GSS&W (frequency range between 1 and 2 Hz, lasting 3-50 s). The predominant clinical correlate was bilateral tonic activity followed by a period of inattentiveness. In general, these seizures were differentiated from the patient's typical tonic seizures by this protracted period of impaired attentiveness. CONCLUSIONS: We describe a heretofore underrecognized and poorly characterized seizure type in patients with symptomatic generalized epilepsy, which we have termed tonic-absence seizures. Clinically and electrographically, this consists of a tonic seizure with GPFA followed by an absence seizure with GSS&W.

Video-EEG monitoring in the elderly: a review of 94 patients.

PURPOSE: We sought to determine the utility and results of video-EEG monitoring in elderly patients. There is an increased incidence of epilepsy in the elderly population. Few studies have assessed the characteristics of epileptic and nonepileptic seizures in this age group. Diagnostic evaluation with video-EEG monitoring is a means to distinguish these different types of events. METHODS: The authors reviewed all patients aged 60 years and older who were admitted to the epilepsy monitoring unit at Columbia-Presbyterian Medical Center from January 21, 1991, to April 12, 1999. RESULTS: A total of 94 patients and 99 patient admissions were identified, accounting for 8% of all admissions. The average age was 70 years, and the mean length of stay was 3.8 days. Typical events were recorded in 75 of the 99 patient admissions. A total of 118 seizures was recorded in 46 patients, and 98 nonepileptic events were seen in 27 patients. Of the patients with nonepileptic events, 13 had psychogenic seizures. The majority of patients with nonepileptic events were taking antiepileptic medication. Whereas 76% of the patients with epileptic events had interictal epileptiform discharges, 26% of the patients with nonepileptic events had epileptiform discharges as well. CONCLUSIONS: Video-EEG monitoring in the elderly leads to a definitive diagnosis in the majority of patients in a relatively short time. Interictal recordings are inadequate in determining the nature of paroxysmal events. Nonepileptic events are common in the elderly, including psychogenic seizures, and these are often misdiagnosed and mistreated as epileptic seizures.