Stereoelectroencephalography: a review of complications and outcomes in a new Australian centre.

BACKGROUND: Surgical management of refractory focal epilepsy requires preoperative localisation of the epileptogenic zone (EZ). To augment noninvasive studies, stereoelectroencephalography (SEEG) is being increasingly adopted as a form of intracranial monitoring. AIMS: This study aimed to determine the rate of complications for patients undergoing SEEG and to report the success of SEEG with regard to EZ detection and seizure outcome following definitive surgery. METHODS: A retrospective cohort design investigated all cases of SEEG at our institution. Surgical, anaesthetic and medical complications with subsequent epilepsy surgery and seizure outcome data were extracted from medical records. Multivariate logistic regression was used to investigate the relationship between both the number of electrodes per patient and the duration of SEEG recording with the rate of complications. RESULTS: Sixty-four patients with 66 implantations were included. Headache was the most common complication (n = 54, 82%). There were no major surgical or medical complications. Two anaesthetic complications occurred. EZ localisation was successful in 63 cases (95%). Curative intent surgery was performed in 39 patients (59%) and 23 patients achieved an Engel class I outcome (59% of those undergoing surgery). The number of electrodes and duration of recording were not associated with complications. CONCLUSIONS: No patients in our series experienced major surgical or medical complications and we have highlighted the challenges associated with neuroanaesthesia in SEEG. Our complication rates and seizure outcomes are equivalent to published literature indicating that this technique can be successfully established in newer centres using careful case selection. Standardised reporting of SEEG complications should be adopted.

High-fidelity dendritic sodium spike generation in human layer 2/3 neocortical pyramidal neurons.

Dendritic spikes function as cardinal components of rodent neocortical circuit computations. Recently, the biophysical properties of human pyramidal neurons (PNs) have been reported to be divergent, raising the question of whether dendritic spikes have homologous roles in the human neocortex. To directly address this, we made electrical recordings from the soma and apical dendrites of human and rat layer 2/3 PNs of the temporal cortex. In both species, dendritic excitatory input led to the initiation of sodium-channel-mediated dendritic spikes. Dendritic sodium spikes could be generated across a wide input range, exhibited a similar frequency range of activation, and forward-propagated with high-fidelity to implement stereotyped computations in human and rat PNs. However, the physical expansion and complexification of the apical dendritic trees of human PNs allowed the enriched expression of dendritic spike generation. The computational capacity of human PNs is therefore enhanced by the widespread implementation of a conserved dendritic integration mechanism.

Effect of immunotherapy on intracranial EEG in patients with seronegative autoimmune-associated epilepsy

Objective: Immunity is increasingly implicated in the aetiology of certain types of epilepsy, however, the clinical and EEG features in such cases remain poorly defined. We present stereo-electroencephalography (SEEG) findings in patients who were thought to have autoantibody-mediated epilepsy on the basis of clinical improvement after administration of immunotherapy (IT). Methods: All patients undergoing SEEG implantation in our service were reviewed and those receiving immunotherapy, either before, during, or after SEEG evaluation, were identified. Response to immunotherapy was defined as greater than 50% seizure reduction. We compared the clinical features and SEEG findings between those who responded to immunotherapy and those who did not. Results: Sixty-two cases underwent SEEG evaluation. Of these, 11 received immunotherapy and three cases demonstrated a positive clinical benefit. The three responsive patients had multifocal seizure onset, repetitive spiking interictally and ictally, perisylvian semiology, seizure onset in the posterior perisylvian regions, and normal neuroimaging. Significance: Seronegative immunotherapy responders exist in epilepsy populations, therefore the diagnosis of autoimmune-associated epilepsy should be considered before proceeding to epilepsy surgery. Possible features of an electroclinical syndrome associated with autoimmunity may include multifocal seizure onset, perisylvian involvement, and normal neuroimaging.

A woman with visual loss, amenorrhoea and polyuria: the first reported case of nodular lymphocyte-predominant Hodgkin lymphoma presenting with hypopituitarism.

SUMMARY: A 34-year-old woman presented 18 months post-partum with blurred vision, polyuria, amenorrhoea, headache and general malaise. Comprehensive clinical examination showed left superior temporal visual loss only. Initial investigations revealed panhypopituitarism and MRI demonstrated a sellar mass involving the infundibulum and hypothalamus. Lymphocytic hypophysitis was suspected and high dose glucocorticoids were commenced along with desmopressin and thyroxine. However, her vision rapidly deteriorated. At surgical biopsy, an irresectable grey amorphous mass involving the optic chiasm was identified. Histopathology was initially reported as granulomatous hypophysitis. Despite the ongoing treatment with glucocorticoids, her vision worsened to light detection only. Histopathological review revised the diagnosis to partially treated lymphoma. A PET scan demonstrated avid uptake in the pituitary gland in addition to splenic involvement, lymphadenopathy above and below the diaphragm, and a bone lesion. Excisional node biopsy of an impalpable infraclavicular lymph node confirmed nodular lymphocyte-predominant Hodgkin lymphoma. Hyper-CVAD chemotherapy was commenced, along with rituximab; fluid-balance management during chemotherapy (with its requisite large fluid volumes) was extremely complex given her diabetes insipidus. The patient is now in clinical remission. Panhypopituitarism persists; however, her vision has recovered sufficiently for reading large print and driving. To the best of our knowledge, this is the first reported case of Hodgkin lymphoma presenting initially as hypopituitarism. LEARNING POINTS: Lymphoma involving the pituitary is exceedingly rare and, to the best of our knowledge, this is the first reported case of nodular lymphocyte-predominant Hodgkin lymphoma presenting as hypopituitarism. There are myriad causes of a sellar mass and this case highlights the importance of reconsidering the diagnosis when patients fail to respond as expected to appropriate therapeutic intervention. This case highlights the difficulties associated with managing panhypopituitary patients receiving chemotherapy, particularly when this involves large volumes of i.v. hydration fluid.

Clival prolactinoma masquerading as a chordoma: a case report.

Ectopic pituitary adenomas are a rare clinical entity and are frequently mistaken for other base of skull lesions on imaging. We report the clinical presentation and management of a woman presenting with an ectopic prolactinoma located in the clivus. A 66-year-old female presented with a 6-month history of headaches and light-headedness. Anatomical imaging demonstrated a clival lesion most suspicious for chordoma. Endocrinological assessment revealed modestly increased prolactin level with lower-than-expected gonadotrophins levels for her age. Surgical resection confirmed an ectopic prolactinoma. A skull base lesion in a patient with hormonal derangement should lend to a high clinical suspicion of an EPA as they may be treated with medications before surgery. Guidelines could assist clinicians investigating skull-based lesions to identify the rare, but important diagnosis of ectopic pituitary adenomas.

Electroclinical insights into autoimmune epilepsy.

PURPOSE: Chronic autoimmune epilepsy is an increasingly recognised entity however its clinical and electrographic features remain poorly understood. We present a case undergoing diagnostic Stereo-electroencephalography implantation that was found to have a multifocal perisylvian epilepsy with unique electrographic features and is now seizure free with immunotherapy. METHODS: The patient had antibody negative refractory perisylvian epilepsy and underwent implantation of the perisylvian-temporal networks. Immunomodulatory treatment was administered during SEEG. RESULTS: SEEG demonstrated a multifocal perisylvian epilepsy with strong involvement of the posterior insula. There was almost continuous spiking seen interictally from multiple foci within the right hemisphere and independent seizures were generated from 5 locations. After treatment with intravenous methylprednisone and immunoglobulin during SEEG, spiking and seizures terminated while still off anti-seizure medications. The patient remains seizure free on immunotherapy. CONCLUSION: This case highlights the importance of considering autoimmunity in the differential diagnosis of refractory epilepsy, especially perisylvian epilepsy. It also highlights the need to define a clinical phenotype associated with autoantibodies in epilepsy, as there are likely many cases who are not positive for one of the commercially available tests. This case also provides insights into the possible features of an electroclinical syndrome associated with autoimmunity.

Refractory epilepsy secondary to anti-GAD encephalitis treated with DBS post SEEG evaluation: a novel case report based on stimulation findings.

We report a case of medically refractory anti-GAD encephalitis which was treated with deep brain stimulation (DBS) after seizure termination was achieved using cortical stimulation during stereo-electroencephalography (SEEG) evaluation. The patient underwent bilateral SEEG implantation and cortical stimulation. Upon stimulation, mimicking the intrinsic seizures (at 1 Hz), it was possible to induce seizures with typical semiology, on multiple attempts. Stimulation during these seizures with high frequency (50 Hz) resulted in complete termination of the seizure. DBS was inserted after the SEEG evaluation, targeting the bilateral anterior nucleus of the thalamus. There was a sustained reduction in seizure frequency and severity 12 months post insertion. There were also improvements in quality of life. To the best of our knowledge, this is the only case reported in which DBS was successfully used to treat refractory epilepsy in a patient with seizures that were proven to be responsive to electrical stimulation during SEEG recording.