Faisal Al-Otaibi

Neuromodulation in epilepsy.

Neuromodulation strategies have been proposed to treat a variety of neurological disorders, including medication-resistant epilepsy. Electrical stimulation of both central and peripheral nervous systems has emerged as a possible alternative for patients who are not deemed to be good candidates for resective procedures. In addition to well-established treatments such as vagus nerve stimulation, epilepsy centers around the world are investigating the safety and efficacy of neurostimulation at different brain targets, including the hippocampus, thalamus, and subthalamic nucleus. Also promising are the preliminary results of responsive neuromodulation studies, which involve the delivery of stimulation to the brain in response to detected epileptiform or preepileptiform activity. In addition to electrical stimulation, novel therapeutic methods that may open new horizons in the management of epilepsy include transcranial magnetic stimulation, focal drug delivery, cellular transplantation, and gene therapy. We review the current strategies and future applications of neuromodulation in epilepsy.

Surgical Techniques for the Treatment of Temporal Lobe Epilepsy

Temporal lobe epilepsy (TLE) is the most common form of medically intractable epilepsy. Advances in electrophysiology and neuroimaging have led to a more precise localization of the epileptogenic zone within the temporal lobe. Resective surgery is the most effective treatment for TLE. Despite the variability in surgical techniques and in the extent of resection, the overall outcomes of different TLE surgeries are similar. Here, we review different surgical interventions for the management of TLE.

The cardioinhibitory responses of the right posterior insular cortex in an epileptic patient.

Background: The insular cortex (IC) has long been implicated in the central regulation of the autonomic nervous system but its precise role remains to be determined. We studied the role of IC in cardiovascular control using a multimodality approach consisting of isometric handgrip exercises, functional magnetic resonance imaging (fMRI) activation during handgrip exercises, and direct electrical stimulations of the posterior right IC in a single patient. Method: A 24-year-old patient had medically intractable epilepsy secondary to a small ganglioglioma in the right posterior IC. His cardiovascular responses to 30 and 70% maximum voluntary contraction (MVC) handgrip exercises were recorded in the lab and during fMRI and compared to those of 10 healthy control subjects. He subsequently underwent stereo-electroencephalography with depth electrodes in the right posterior IC and further study of the cardiovascular responses to electrical stimulation at rest and during MVC handgrip exercises. Result: fMRI data showed nearly absent activation in the right IC relative to healthy subjects. At rest, electrical stimulation of the right posterior inferior IC but not the superior IC suppressed heart rate (HR) by 3 beats per minute. During exercise, the HR response to isometric handgrip contraction was weakened when the right posterior inferior IC was simultaneously stimulated. Conclusion: This study shows that, in this patient, the right posterior inferior IC is an important cardioinhibitory center and interference with this region alters the cardiac response to handgrip exercise. Further investigations are required to examine the cardiovascular control of the IC.

Independent component analysis of subdurally recorded occipital seizures

OBJECTIVE To study the components of occipital seizures using independent component analysis (ICA) of subdurally recorded electroencephalogram (EEG) data. METHODS Twenty-seven subdurally recorded occipital seizures from eight patients were studied. ICA was performed, and the resulting independent components (ICs) were compared with respect to their power, frequency, degree of spread within the epileptogenic zone, and propagation patterns. The ictal ICs were further subdivided into propagating and non-propagating types. RESULTS ICA provided information over and above that supplied by standard visual EEG analysis, confirming that all the seizures originated in the occipital lobe, and affording additional knowledge regarding the nature of the seizure onset zone. Each seizure was composed of multiple ICs, some of which propagated while others remained within the epileptogenic zone. There was no statistical difference between the propagating and non-propagating ICs with respect to power or frequency. However, propagating ICs involved a significantly greater number of recording electrodes at their onset when compared to the non-propagating ICs. CONCLUSIONS The propagation likelihood of ICs in occipital seizures is independent of their power or frequency, but it is dependent on the volume of brain giving rise to that signal; ICs that are generated by a greater volume of brain within the epileptogenic zone are more likely to propagate. SIGNIFICANCE This study shows that ICA has the potential to be used to redefine the epileptogenic zone and guide the extent of cortisectomy for the treatment of patients with medically intractable occipital epilepsy.

Clinically silent magnetic resonance imaging findings after subdural strip electrode implantation

OBJECT Subdural strip electrodes (SSEs) are often used as part of the workup in patients being considered for epilepsy surgery. To assess for complications or to confirm electrode placement, postoperative imaging is often performed. Imaging performed with the electrodes in situ is limited by streak artifact on CT and susceptibility artifact on MR imaging. Therefore, the first opportunity for high-quality postoperative imaging is following explantation of electrodes. There is no data available to determine what would be the expected MR imaging appearance following insertion of SSE. The purpose of this study is to describe the MR imaging findings in asymptomatic patients who underwent insertion of SSEs. METHODS Twenty consecutive patients who underwent SSE insertion were studied. Within 24 hours after removal of the electrodes, each patient underwent MR imaging that included axial T2-weighted, gradient echo, diffusion weighted, and coronal FLAIR sequences. No significant symptoms were reported by any of the patients. The studies were reviewed by an experienced, blinded neuroradiologist and categorized. RESULTS Of the 20 patients studied, 11 were female (mean age 36 years). Clinically silent postexplantation MR imaging abnormalities were found in all patients: subdural hematomas in 7 (35%), cortical contusions in 5 (25%), local edema in 5 (25%), trans-bur hole cortical herniation in 5 (25%), subdural hygromas in 2 (10%), and pneumocranium in 4 (20%). The MR imaging abnormalities were subdivided into 2 types: Type A, abnormalities related to the site of electrode insertion; and Type B, abnormalities related to the location of the electrodes. The most common location for a Type A abnormality was occipitotemporal, with cortical contusions occurring in this location in 18% of cases, local edema in 24%, and trans-bur hole herniation in 24%. The next most common location was frontal, with cortical contusions found in this location in 10% of cases, local edema in 5% and trans-bur hole herniation in 5%. The most common Type B abnormality was a subdural hematoma, followed by pneumocranium and subdural hygroma. CONCLUSIONS Clinically silent MR imaging abnormalities are common following SSE placement. Knowledge of these findings would be of assistance in interpreting MR imaging results in patients being assessed for complications.

Miliary tuberculomas of the brain: case report

Tuberculosis (TB) of the central nervous system (CNS) is still prevalent in many developing countries. Tuberculoma is always considered in the differential diagnosis of enhancing intra-axial lesions of the brain. Brain tuberculomas can present in many different clinical and radiological patterns, disseminated or miliary brain tuberculomas are very rare. We describe the case of a 25-year-old immunocompetent female with miliary brain tuberculomas. She presented with a history of progressive headache and unsteady gait. Serial Magnetic resonance imaging (MRI) studies revealed growing, multiple small enhancing lesions in the brain, most lesions measured approximately 2mm in diameter, in both the supratentorial and infratentorial compartments. Her investigation failed to reveal any evidence of TB outside the CNS. Open biopsy revealed multiple caseating granulomas and mycobacterin tuberculosis was cultured. She improved clinically and radiologically after starting anti-tuberculous pharmacotherapy. The clinical course, radiological images and pathological studies of this patient are presented. In conclusion miliary brain tuberculomas are rare and unique clinical and radiological entity. It may affect immunocompetent individuals with no other signs of other systemic involvement.

Occult Orbitocranial Penetrating Pencil Injury in a Child

Transorbital slow-penetrating injury is an uncommon type of head injury that is seen more often in the pediatric age group. This type of injury can be occult, which is often associated with serious complications. We report on a 4-year-old female who presented with orbital swelling after an unwitnessed right orbital injury following a fall on her face at her school. Three days after injury, the presence of a foreign body was discovered on imaging study when she presented with orbital swelling and purulent discharges. She recovered well after surgical and medical management. This paper sheds light on the importance of high suspicion for the presence and early surgical management of a penetrating foreign body.

Transorbital craniocerebral occult penetrating injury with cerebral abscess complication.

Transorbital intracranial penetrating injury is an uncommon mechanism of head injury. These injuries can be occult during the initial clinical presentation. Certain patients develop an intracranial cerebral infection. Herein, we report a 5-year-old child with an occult transorbital intracranial penetrating injury caused by a pen. A retained pen tip was found at the superior orbital roof and was not noticed at initial presentation. This was complicated by a right frontal lobe cerebral abscess. This paper emphasizes the importance of orbitocranial imaging in any penetrating orbital injury. A review of the literature on intracranial infection locations in relation to the route and mechanism of injury is included to complement this report.

Turcot Syndrome: A Synchronous Clinical Presentation of Glioblastoma Multiforme and Adenocarcinoma of the Colon

Turcot syndrome (TS) is a rare hereditary disorder clinically characterized by the occurrence of primary tumors of the colon and the central nervous system (CNS). Here we present the case of an 11-year-old boy with a synchronous clinical presentation of both glioblastoma multiforme (GBM) and colonic adenocarcinoma. A molecular genetic study revealed microsatellite instability in the DNA mismatch repair (MMR) gene. This patient ultimately survived for 13 months after clinical presentation. Based on this case study, the synchronous presentation of glioblastoma multiforme and adenocarcinoma of the colon might suggest a shorter survival rate for patients with Turcot syndrome. A literature review complements this paper.

Epilepsy Surgery Series: A Study of 502 Consecutive Patients from a Developing Country

Purpose. To review the postoperative seizure outcomes of patients that underwent surgery for epilepsy at King Faisal Specialist Hospital & Research Centre (KFSHRC). Methods. A descriptive retrospective study for 502 patients operated on for medically intractable epilepsy between 1998 and 2012. The surgical outcome was measured using the ILAE criteria. Results. The epilepsy surgery outcome for temporal lobe epilepsy surgery (ILAE classes 1, 2, and 3) at 12, 36, and 60 months is 79.6%, 74.2%, and 67%, respectively. The favorable 12- and 36-month outcomes for frontal lobe epilepsy surgery are 62% and 52%, respectively. For both parietal and occipital epilepsy lobe surgeries the 12- and 36-month outcomes are 67%. For multilobar epilepsy surgery, the 12- and 36-month outcomes are 65% and 50%, respectively. The 12- and 36-month outcomes for functional hemispherectomy epilepsy surgery are 64.2% and 63%, respectively. According to histopathology diagnosis, mesiotemporal sclerosis (MTS) and benign CNS tumors had the best favorable outcome after surgery at 1 year (77.27% and 84.3%, resp.,) and 3 years (76% and 75%, resp.,). The least favorable seizure-free outcome after 3 years occurred in cases with dual pathology (66.6%). Thirty-four epilepsy patients with normal magnetic resonance imaging (MRI) brain scans were surgically treated. The first- and third-year epilepsy surgery outcome of 17 temporal lobe surgeries were (53%) and (47%) seizure-free, respectively. The first- and third-year epilepsy surgery outcomes of 15 extratemporal epilepsy surgeries were (47%) and (33%) seizure-free. Conclusion. The best outcomes are achieved with temporal epilepsy surgery, mesial temporal sclerosis, and benign CNS tumor. The worst outcomes are from multilobar surgery, dual pathology, and normal MRI.