EMG, EEG, and Neurophysiology in Clinical Practice

Transcription

1 Mayo School of Continuous Professional Development EMG, EEG, and Neurophysiology in Clinical Practice Matthew T. Hoerth, M.D. Ritz-Carlton, Amelia Island, Florida January 29-February 4, MFMER

2 Mayo School of Continuous Professional Development Intracranial recordings and HFO s Matthew T. Hoerth, M.D. Ritz-Carlton, Amelia Island, Florida January 29-February 4, MFMER

3 Disclosure Relevant financial relationships None Off-label/investigational uses None 2016 MFMER

4 Overview Treatment of Intractable Focal Epilepsy Epilepsy Surgery Review principles of Intracranial Recordings Electrocorticography High Frequency Oscillations Neuromodulation for Epilepsy VNS, DBS, RNS 2016 MFMER

5 Refractory Epilepsy: What if medications do not work? 2.5 million with epilepsy in the U.S. >50% with partial epilepsy 30% refractory to medical therapy 2000 epilepsy surgeries/year 60-70% of those evaluated for epilepsy surgery get a resection Refs: Epilepsy: A report to the nation. EFA 1999; Kwan &Brodie NEJM 2000, 342: 314; Engel et al., Surgical Treatment of the Epilepsies, 1993; Zimmerman & Sirven Mayo Clinic Proc 2003, 78: MFMER

6 Options for epilepsy surgery Selective Amagydalohippocampectomy Anterior temporal lobectomy Lesionectomy Focal cortical resection Multiple subpial transection Hemispherectomy Corpus Callosotomy NeuroModulation Devices 2016 MFMER

7 Evaluation for Epilepsy Surgery H&P Ictal/interical video EEG Structural imaging: MRI Functional imaging: PET, SPECT, fmri Neuropsychological testing Wada test Multidisciplinary conference Epileptologists Epilepsy surgeon Neuropyschologist Radiologist EEG Technologists Nursing Staff (inpatient/outpatient) Administrative support Research support 2016 MFMER

8 Epilepsy Surgery: Goals Removal of the epileptogenic zone Seizure freedom Working & Driving Limit morbidity and mortality 2016 MFMER

9 Indications for Intracranial EEG Monitoring Localization of seizure onset when non-invasive testing is inadequate Tailoring of cortical resection Mapping cortical function 2016 MFMER

10 Temporal Depth Electrodes 2016 MFMER

11 2016 MFMER

12 The Operating Room You NEED to know where your electrodes are being placed Without knowledge of placement you cannot plug in electrodes appropriately All the tails have different colors Each package is different Double-sided grids Verify that electrodes are working properly 2016 MFMER

13 Subdural Electrodes 2016 MFMER

14 2016 MFMER

15 2016 MFMER

16 Safety for the Grid/Depth Patient Increased level of risk Risk related to surgery Bleeding Infection Swelling Pain related to surgery Incision pain Jaw pain 2016 MFMER

17 Post-op day 1 4 days later 2016 MFMER

18 Intracranial Monitoring Advantages More localization value Get the address not just the state Less artifact Disadvantages Invasive Narrow coverage If seizure does not occur adjacent to electrode then there is no localization value 2016 MFMER

19 Intracranial Monitoring Typically a bipolar montage is used Montaging by row May need to make additional montages based on recording Usually a secondary referential montage is used Subdural ground/reference Much lower sensitivities 2016 MFMER

20 50 mcv/mm 7 mcv/mm 2016 MFMER

21 2016 MFMER

22 High Frequency Oscillations (HFOs) Some interictal EEG spikes correspond to the epileptogenic zone, some do NOT High sampling (>800 Hz) of scalp and depth electrodes can show interictal local field potentials (HFOs). HFOs occur spontaneously during slow wave sleep and can be evoked during sensory information processing. In the epileptic brain, interictal pathological HFOs are associated with brain areas capable of generating spontaneous seizures HFOs can occur either independently or coincident with some EEG spikes MFMER

23 High Frequency Oscillations (HFOs) Pathological HFOs may identify interictal EEG spikes that reliably reflect the epileptogenic zone Pathological HFOs can occur before or during the onset of some epileptic seizures Pathological HFOs could be an electrophysiologic biomarker of brain areas that are capable of generating spontaneous seizures Capturing pathological HFOs, therefore, could provide important information to identify the epileptogenic zone and help plan surgical resection that may ultimately improve the prognosis of seizure freedom MFMER

24 High Frequency Oscillations (HFOs) 2016 MFMER

25 2016 MFMER Ren, et al. Neurology 2015

26 Brain Mapping fmri Non-invasive Looks at subtle blood flow changes while patients are doing a specific task Labor intensive Biggest limitation is verbal/visuospacial memory 2016 MFMER

27 Brain Mapping Wada Intracranial sodium amytal Most helpful for memory and language lateralization Cannot localize as entire internal carotid vascular territory effected Invasive Very small risk of stroke 2016 MFMER

28 Brain Mapping Cortical stimulation Stimulation through intracranial grid Typically done during Phase II monitoring Early vs. Late in admission Risk of causing a seizure Seizures should not be considered helpful for localization of ictal onset Typically rescue medication is immediately avaliable Patient must be awake and cooperative 2016 MFMER

29 Brain Mapping Cortical stimulation G1 and G2 are chosen Typically will have patient read passage Repetitive Gradually increase stimulation Monitor EEG for after discharges Monitor patient for clinical changes 2016 MFMER

30 Brain Mapping Intraoperative Intracranial SEP Localize primary somatosensory cortex Awake Mapping Stimulation or Serial Testing Motor Speech Sensory Visual 2016 MFMER

31 Surgical Outcomes Can be up to 80% curative in the most ideal circumstances Minimally invasive approaches are being attempted Laser Ablation Ultrasound Must know neuroanatomy and neurophysiology to be successful 2016 MFMER