The threshold of cortical electrical stimulation for mapping sensory and motor functional areas.

This study aimed to investigate the threshold of cortical electrical stimulation (CES) for functional brain mapping during surgery for the treatment of rolandic epilepsy. A total of 21 patients with rolandic epilepsy who underwent surgical treatment at the Beijing Institute of Functional Neurosurgery between October 2006 and March 2008 were included in this study. Their clinical data were retrospectively collected and analyzed. The thresholds of CES for motor response, sensory response, and after discharge production along with other threshold-related factors were investigated. The thresholds (mean ± standard deviation) for motor response, sensory response, and after discharge production were 3.48 ± 0.87, 3.86 ± 1.31, and 4.84 ± 1.38 mA, respectively. The threshold for after discharge production was significantly higher than those of both the motor and sensory response (both p<0.05). A negative linear correlation was found between the threshold of after discharge production and disease duration. Using the CES parameters at a stimulation frequency of 50 Hz and a pulse width of 0.2 ms, the threshold of sensory and motor responses were similar, and the threshold of after discharge production was higher than that of sensory and motor response.

Surgical treatment of patients with drug-resistant hypermotor seizures.

PURPOSE: To describe the clinical, electrophysiologic, neuroradiologic, and histologic findings in our patients with drug-resistant hypermotor seizures (HMSs) and to evaluate the outcome of their surgical treatment. METHODS: Twenty-three patients were identified by criteria for drug-resistant HMS. Surgical treatment and presurgical evaluation modalities including semiology, magnetic resonance imaging (MRI), interictal/ictal scalp video-EEG (electroencephalography), and intracranial recording were analyzed retrospectively. RESULTS: The common seizure frequency of 60-300 per month was observed among 15 patients. Sixteen patients (69.6%) experienced auras such as fear and palpitation. Marked agitation was observed in 12 patients and mild agitation in 11 patients. Groaning/shouting and asymmetric posturing were common accompanying symptoms. Asymmetric posturing was observed more often in patients with mild agitation than in those with marked agitation (p = 0.027). MRI detected focal abnormalities in six patients. Intracranial recording was conducted in 16 patients. The origins of seizures were localized in mesial frontal cortex in four patients, dorsolateral frontal cortex in four patients, and mesial temporal cortex in two patients. The epileptogenic zones (EZs) were resected from the frontal lobe in 21 patients and from the temporal lobe in 2 patients. The follow-up ranged from 12-60 months. Seventeen patients (73.9%) had been seizure-free, 11 of whom had presented with marked agitation (11 of 12) and 6 with mild agitation (6 of 11) (p = 0.069). Histologic examinations demonstrated focal cortical dysplasia (FCD) in 18 patients. DISCUSSION: The HMSs can originate from both the mesial and dorsolateral frontal cortex, and occasionally from the temporal lobe. Patients with drug-resistant HMSs should be recommended for resective surgical treatment.

Surgical treatment for musicogenic epilepsy.

We report a patient with medically intractable musicogenic epilepsy (ME) who was treated with surgery. Using the non-invasive methods of ictal and interictal electroencephalography (EEG), MRI, interictal single photon emission computed tomography and clinical manifestations, we first localized the musicogenic seizures (MS). The ictal onset zone was then further localized using intracranial EEG to the middle part of the left superior temporal gyrus. Surgical resection of the epileptogenic zone was then performed. The patient had two seizures within 2 weeks post-operatively, but has then had no seizures during the following year (Engel class II). The results suggest that patients who have medically intractable ME combined with unilateral ictal onset zones should be considered for the surgical treatment of epilepsy.

Surgery for perirolandic epilepsy: Epileptogenic cortex resection guided by chronic intracranial electroencephalography and electric cortical stimulation mapping.

SUBJECT: The objective of this study was to assess outcome with regard to seizure status and neurological function in patients undergoing resective surgery involving the perirolandic area. METHOD: All 15 patients who underwent perirolandic cortical resection between October 2006 and September 2007 at the Comprehensive Epilepsy Centre of Beijing Xuanwu Hospital were included in the study. The locations of functional cortical areas, ictal onset zones and epileptogenic lesions were mapped by chronic intracranial EEG recordings and electric cortical stimulation. Seizure outcome was determined using the modified classification of Engel and colleagues. Motor and sensory deficits were monitored. RESULTS: At last follow-up 5 patients (33%) were in Engel class I, 4 (27%) were in class II, 3 (20%) were in class III, and 3 (20%) were in class IV. Nine patients suffered immediate functional deficits; 8 of these recovered completely within 2 weeks to 3 months of surgery. One had mild persistent loss of finger motor control. CONCLUSION: After accurate presurgical evaluation using invasive recordings and functional brain mapping, epileptogenic cortical resection can give excellent results and few deficits in patients with perirolandic epilepsy.