Seizure outcome after epilepsy surgery in tuberous sclerosis complex: Results and analysis of predictors from a multicenter study.

Epilepsy surgery is recommended in selected patients with Tuberous Sclerosis Complex (TSC). However, reports on predictive factors of seizure outcome are variable. Here we report on seizure and cognitive outcome of 35 TSC patients who received surgery for refractory epilepsy in 7 Italian centers over a period of 22 years (1997-2019). The rate of seizure-free individuals at last follow-up (mean 7.5 years, range 1-21 years) was 51%. Patients with longer follow-up (≥10 years) had a lower rate of Engel I outcome (11.1%) than those who received surgery in the last 10 years (65.4%, p = 0.003). Factors associated with Engel II, III, IV outcome in our cohort included: high number of cortical tubers (≥5); presence of subependymal nodules (SENs); seizure onset before age 1 year; and multifocal interictal epileptic discharges (IEDs) on electroencephalogram (EEG). A subset of patients evaluated with Vineland Adaptive Behaviour Scales (VABS) showed developmental gains, in line with their developmental trajectories, but no improvement in standard scores after surgery was noted. Our study demonstrates that the rates of successful seizure outcome of epilepsy surgery in TSC have improved in the last 10 years. More than half of the patients achieved seizure freedom, and a high proportion of affected individuals experienced a reduction in seizure burden and in antiseizure medications. A comprehensive assessment after surgery should be performed in TSC patients to evaluate the overall neurodevelopmental outcome, as measures that are based only on seizure control do not adequately identify the benefits of surgery on global functioning in these patients.

The course of language functions after temporal lobe epilepsy surgery: a prospective study.

BACKGROUND AND PURPOSE: Anterior temporal lobectomy (ATL) within the language-dominant hemisphere can impair naming. This prospective study examined the pre-operative to post-operative course of different language components, clarifying which changes are relevant within the short-term and long-term outcome of language. METHODS: Patients with drug-resistant temporal lobe epilepsy (TLE) were evaluated using the Token, Boston Naming and Word Fluency tests assessing sentence comprehension and word-finding on visual, semantic or phonemic cues. RESULTS: A total of 106 patients were evaluated before and 6 months, 1 and 2 years after ATL; 60 patients were also evaluated after 5 years and 38 controls were assessed at baseline. Seizure outcome was comparable between the left and right TLE patients. Before surgery, naming and word fluency were impaired in the left and right TLE patients, whereas sentence comprehension was normal. After left or right ATL, word fluency progressively improved, naming showed early worsening and late improvement after left ATL and progressive improvement after right ATL, and sentence comprehension did not change. At the 5-year follow-up, naming improvement was clinically significant in 31% and 71% of the left and right TLE patients, respectively. Pre-operative naming, ATL laterality, schooling, and post-operative seizure frequency and number of antiepileptic drugs predicted post-operative naming. Pre-operative word fluency and schooling predicted post-operative word fluency. CONCLUSIONS: Left or right TLE can impair word-finding but not sentence comprehension. After ATL, word-finding may improve for a long time, depending on TLE laterality, seizure control and mental reserve. These findings may clarify prognosis prior to treatment.

Preoperative language lateralization in temporal lobe epilepsy (TLE) predicts peri-ictal, pre- and post-operative language performance: An fMRI study.

In patients with temporal lobe epilepsy (TLE), assessment of language lateralization is important as anterior temporal lobectomy may lead to language impairments. Despite the widespread use of fMRI, evidence of its usefulness in predicting postsurgical language performance is scant. We investigated whether preoperative functional lateralization is related to the preoperative language performance, peri-ictal aphasia, and can predict language outcome one year post-surgery. We studied a total of 72 TLE patients (42 left, 30 right), by using three fMRI tasks: Naming, Verb Generation and Fluency. Functional lateralization indices were analyzed with neuropsychological scores and presence of peri-ictal aphasia. The key findings are:1)Both left and right TLE patients show decreased left lateralization compared to controls.2)Lateralization correlates with language performance before surgery. In left TLE, decreased left lateralization correlates with better fluency performance. In right TLE, increased left lateralization during the Naming task correlates with better naming.3)Left lateralization correlates with peri-ictal aphasia in left TLE patients.4)Lateralization correlates with language performance after surgery. In a subgroup of left TLE who underwent surgery (17 left), decreased left lateralization is predictive of better naming performance at 6 and 12 months after surgery. The present study highlights the clinical relevance of fMRI language lateralization in TLE, especially to predict language outcome one year post-surgery. We also underline the importance of using fMRI tasks eliciting frontal and anterior temporal activations, when studying left and right TLE patients.

Surgical treatment of drug-resistant nocturnal frontal lobe epilepsy.

Of the cases with nocturnal frontal lobe epilepsy (NFLE) approximately 30% are refractory to antiepileptic medication, with several patients suffering from the effects of both ongoing seizures and disrupted sleep. From a consecutive series of 522 patients operated on for drug-resistant focal epilepsy, 21 cases (4%), whose frontal lobe seizures occurred almost exclusively (>90%) during sleep, were selected. All patients underwent a comprehensive pre-surgical evaluation, which included history, interictal EEG, scalp video-EEG monitoring, high-resolution MRI and, when indicated, invasive recording by stereo-EEG (SEEG). There were 11 males and 10 females, whose mean age at seizure onset was 6.2 years, mean age at surgery was 24.7 years and seizure frequency ranged from <20/month to >300/month. Nine patients reported excessive daytime sleepiness (EDS). Prevalent ictal clinical signs were represented by asymmetric posturing (6 cases), hyperkinetic automatisms (10 cases), combined tonic posturing and hyperkinetic automatisms (4 cases) and mimetic automatisms (1 case). All patients reported some kind of subjective manifestations. Interictal and ictal EEG provided lateralizing or localizing information in most patients. MRI was unrevealing in 10 cases and it showed a focal anatomical abnormality in one frontal lobe in 11 cases. Eighteen patients underwent a SEEG evaluation to better define the epileptogenic zone (EZ). All patients received a microsurgical resection in one frontal lobe, tailored according to pre-surgical evaluations. Two patients were operated on twice owing to poor results after the first resection. Histology demonstrated a Taylor-type focal cortical dysplasia (FCD) in 16 patients and an architectural FCD in 4. In one case no histological change was found. After a post-operative follow-up of at least 12 months (mean 42.5 months) all the 16 patients with a Taylor's FCD were in Engel's Class Ia and the other 5 patients were in Engel's Classes II or III. After 6 months post-surgery EDS had disappeared in the 9 patients who presented this complaint pre-operatively. It is concluded that patients with drug-resistant, disabling sleep-related seizures of frontal lobe origin should be considered for resective surgery, which may provide excellent results both on seizures and on epilepsy-related sleep disturbances. An accurate pre-surgical evaluation, which often requires invasive EEG recording, is mandatory to define the EZ. Further investigation is needed to explain the possible causal relationships between FCD, particularly Taylor-type, and sleep-related seizures, as observed in this cohort of NFLE patients.