Focused Ultrasound Neuromodulation for Treatment of Temporal Lobe Epilepsy

Non-invasive and controllable suppression of regional brain activity may open new avenues for the treatment and management of epilepsy. There is good evidence that direct stimulation of epileptogenic sources can powerfully suppress seizure rates, but so far minimally invasive attempts have shown limited success. Currently, there are no approved non-invasive procedures for seizure suppression.

Focused ultrasound (FUS) is a promising new potential treatment, because it can target any region in the brain, regardless of depth, with high spatial specificity. FUS allows for the non-invasive delivery of acoustic energy to a well-localized and circumscribed brain region of a few millimeters in diameter, depositing mechanical or thermal energy. The possibility of transcranial application of FUS into deep brain areas has already been demonstrated by the strategic placement and operation of an array of multiple ultrasound transducers.

The ultrasound based BrainSonix device is a highly novel non-invasive alternative to direct stimulation. Capitalizing on non-invasive high-intensity focused ultrasound (HIFU), BrainSonix, using an animal model, found early evidence of selective suppression of regional neural activity in the brain. Importantly these effects were non-thermal and reversible. Further study is required to validate and characterize the degree of suppressive effects on epilepsy to ensure safe application in human subjects. Low Intensity Focused Ultrasound Pulsation (LIFUP) differs from HIFU because the intensities of ultrasound used are an order of magnitude lower than HIFU. Also, whereas ablative HIFU is administered continuously, LIFUP is administered in short pulses, which reduces energy deposition. The investigators' and others data have demonstrated that administration of ultrasound, as LIFUP, causes a significant, but reversible, neuromodulatory effect, while preventing the tissue from being thermally damaged.

Study Procedures

Visit 1 Assessment The initial assessment will be performed shortly after signing the consent form. The patient will meet with the clinician and baseline demographic information and general physical information will be collected. The patient will also undergo a psychiatric/neurological evaluation, including a neurological exam, and several neuropsychiatric questionnaires using the Brief Symptom Inventory (BSI) self-report, the Beck Depression Inventory (BDI) self-report, a neuropsychiatric battery of tests described in section 9.2.4 below, the Mini-International Neuropsychiatric Interview (MINI) and the Mini-Mental Status Assessment (MMSE). They will also be required to complete an Magnetic Resonance Imaging (MRI) screening questionnaire to detect the presence of any devices that might present a safety risk.

Visit 2 Treatment and Assessment At visit 2, the participant's temporal scalp will be shaved on the side to undergo surgery. Participants will be given the option to have their whole head shaved if they prefer for cosmetic reasons. This process typically takes about 10 minutes.

The location of the epileptic focus will be determined based on previously performed studies as part of the individual's routine epilepsy evaluation. The location of the epileptic focus will be determined based on previously performed studies as part of the individual's routine epilepsy evaluation. Brain MRI, interictal electroencephalogram (EEG), ictal EEG, interictal positron emission tomography (PET), ictal PET, interictal single-photon emission computerized tomography (SPECT), ictal SPECT, interictal magnetoencephalography (MEG), ictal MEG, and magnetic resonance (MR) spectroscopy data may be available and utilized to determine each participant's epileptogenic zone.

LIFUP will be administered to the temporal region on the side to undergo surgery, within the focus producing seizures (as determined by the comprehensive epilepsy evaluation). LIFUP session will take place during the 7 days prior to the operation. See Section 8.2.1 for more details regarding the LIFUP Sonication procedure.

The subject's heart rate and blood pressure will be monitored during the procedure. Routine electrode electroencephalography (EEG) will be recorded immediately before and after the LIFUP sonication session. Recording will last approximately 60 minutes.

The same neurological exam and neuropsychiatric questionnaires using the Brief Symptom Inventory (BSI) self-report, the Beck Depression Inventory (BDI) self-report, and the neuropsychiatric battery of tests described above will be performed at Visit 2, as well. Testing will last approximately 2 hours.

LIFUP Sonication Procedure

Low-Intensity Focused Ultrasound Pulsation (LIFUP) sonications will be conducted using the LIFUP experimental device BX Pulsar 1002 produced by the Brainsonix Corporation. For the purposes of safety LIFUP sonications will be initiated at the Food and Drug Administration (FDA) limit for diagnostic ultrasound. However, the minimally effective dose in humans applications, according to, when derated is approximately 1125mW/cm2.

In the investigators' previous investigational device exception (IDE), the investigators based the intended dose on studies done in small animals. Since then, there has been sufficient work done on humans and non-human primates to warrant a new approach. Many of these studies calculate the estimated intensity inside the brain, but to allow for a more direct comparison the investigators will specify approximate non-derated values.

In 2013 Deffieux and colleagues published a study of focused ultrasound neuromodulation on 2 awake macaque rhesus monkeys. To alter saccadic eye movements they utilized transcranial US at a non-derated spatial-peak, pulse average of (Isppa) of 7.06W/cm2. As they only used single pulses, this corresponds a 100% duty cycle and thus to an Ispta of 7.06W/cm2 as well. Although they did use pulses of only 100ms.

In addition to this non-human primate study, there have also been 2 recent studies of focused ultrasound neuromodulation in humans. In 2014 a group from Virginia Tech conducted a focused ultrasound neurmodulation study on 10 human volunteers, attempting to alter activity in primary somatosensory cortex. They used a non-derated US intensity of 8.6W/cm2. Then, this year a Korean group also published a study used focused ultrasound to modulate primary somatosensory cortex activity on 8 human volunteers. They utilized intensities of 1.5W/cm2.

Of these human or non-human primate studies only one adverse event has been reported from focused ultrasound sonication, specifically one patient complained of feeling "slower" after the procedure for 45 minutes before fully recovering. Thus the investigators intend to utilize US intensities in the same range. The highest level of US intensity the investigators will use is a derated Ispta of 5760mW/cm2. The standard derating equation (It = Iw x e−2αL) addresses the issue of soft tissue absorption, which states that at 6.1mm deep (focal length) at 650KHz, the focal intensity will be reduced by approximately 25%. So the investigators' proposed highest derated intensity corresponds to a non-derated intensity of approximately 7680mW/cm2.

LIFUP will be administered to the temporal region on the side to undergo surgery, within the focus producing seizures (as determined by the comprehensive epilepsy evaluation). In addition the functional magnet resonance imaging (fMRI) recording will be done during the LIFUP to determine the target area of activity and to navigate the focus of the transducer to that area. The ultrasound will be focused on the highest activity area within the temporal lobe. Functional MRI of the brain will be obtained throughout the LIFUP session. Initially LIFUP will be administered below the minimum effective dose determined in previous animal experiments. Up to 8 sonications will be administered during the LIFUP session. The total dose of LIFUP is not to exceed 2 min. The total time within the MRI machine will be up to 90 minutes. See fMRI procedure below for more details.

After the participant is fitted with the transducer they will be placed in the MRI machine and undergo a series of scans. After placing the transducer over the anterior tip of the temporal lobe the participant will undergo fMRI BOLD scans with LIFUP excitation: Tone Burst Duration = 2ms and Pulse Repetition Frequency = 250Hz) at four levels of intensity (720mW/cm2, 1440mW/cm2, 2880mW/cm2 and 5760mW/cm2). Before increasing the intensity, the transducer will be moved approximately 5mm posterior. The excitation scans will be analyzed immediately for evidence of BOLD activation. After the last excitation scan the LIFUP parameters will be changed to inhibitory parameters: Tone Burst Duration = 0.5ms and Pulse Repetition Frequency = 100Hz).

Surgical Resection and Histology After surgical resection of the anterior temporal lobe, histology will be performed on the resected tissue to look for evidence of tissue injury not characteristic of temporal lobe epilepsy or previously identified on the routine brain MRI.

Three Month Follow-up At three months the epilepsy surgeon will assess the healing of the surgical wounds and will conduct a Structural MR. The results will be reported back to the investigator.

Six Month Follow-up At six months the epilepsy surgeon will carry out a neurogical exam, and several neuropsychiatric questionnaires using the Brief Symptom Inventory (BSI) self-report, the Beck Depression Inventory (BDI) self-report, a neuropsychiatric battery of tests described in section 9.2.4 below, the MINI, and the Mini Mental Status Assessment.

Evaluation Methods

MRI Screening Questionnaire The MRI screening questionnaire will be used to detect the presence of any devices that might present a safety risk. This questionnaire is a slightly more restrictive version of that developed by the International Society of Magnetic Resonance in Medicine and is designed to be comprehensive.

Neuropsychological Assessments The following neurological and neuropsychological assessments will be performed at both study visits.

Neurological Exam A neurological exam which includes confrontational visual field testing, strength testing, fine finger movement assessment and testing of primary and secondary sensory modalities will be performed.

Brief Symptom Inventory (BSI) The Brief Symptom Inventory (BSI) self-report questionnaire will be employed to assess for potential psychiatric side effects. This is a self-report questionnaire which takes about 10 minutes to complete, and covers a wide range of psychiatric symptomatology, including somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, paranoid ideation, and psychoticism. The BSI instrument provides an overview of a patient's symptoms and their intensity at a specific point in time. The Global Severity Index (GSI) is designed to help quantify a patient's severity-of-illness and provides a single composite score for measuring the outcome of a treatment program based on reducing symptom severity. The reliability, validity, and utility of the BSI instrument have been tested in more than 400 research studies.

Beck Depression Inventory (BDI-II) The Beck Depression Inventory (BDI-II) will be given to assess mood more thoroughly. This is also a self-report questionnaire, and requires 5 minutes to complete. The Beck Depression Inventory (BDI, BDI-II), created by Dr. Aaron T. Beck, is a 21-question multiple-choice self-report inventory, one of the most widely used instruments for measuring the severity of depression. It is composed of items relating to symptoms of depression such as hopelessness and irritability, cognitions such as guilt or feelings of being punished, as well as physical symptoms such as fatigue, weight loss, and lack of interest in sex. The BDI-II was a 1996 revision of the BDI, developed in response to the American Psychiatric Association's publication of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. The BDI-II contains 21 questions, each answer being scored on a scale value of 0 to 3. The cutoffs used differ from the original: 0-13: minimal depression; 14-19: mild depression; 20-28: moderate depression; and 29-63: severe depression. Higher total scores indicate more severe depressive symptoms.

Neuropsychiatric Battery of Tests The following battery of neuropsychiatric tests will be performed on the study subjects at one of the participant's standard clinical visits, as part of their standard clinical care and at visit 2 following the LIFUP sonication procedure. This battery of tests has been designed to not interfere with their standard clinical care. The Visit 2 scores will be compared to the Visit 1 (Baseline) scores to assess neuropsychiatric changes as a result of the LIFUP procedure.

Seizure Account Participants will be instructed to maintain a daily log of all seizures from the date of consenting until the date of the operation.

Functional MRI (fMRI) BOLD Scans & Analysis Functional MRI recording will be done during the LIFUP to determine the target area of activity and to navigate the focus of the transducer to that area. Furthermore, functional MRI of the brain will be obtained throughout the LIFUP session. The total time within the MRI machine will be up to 90 minutes.

After placing the transducer over the anterior tip of the temporal lobe the participant will undergo fMRI BOLD scans with LIFUP excitation (refer to section 8.2.1). The excitation scans will be analyzed immediately for evidence of BOLD activation, as follows:

Localizer scan If the transducer is not in the appropriate location, then the patient will be removed from the scanner, and it will be adjusted. This process will be repeated until the transducer is in the appropriate location.

Matched Bandwidth high resolution scan - 3 minutes fMRI BOLD scan with no LIFUP (resting state) - 6 minutes fMRI BOLD scan with eight 0.5s excitation pulses at 720mW/cm2 - 6 minutes fMRI BOLD scan with eight 0.5s excitation pulses at 1440mW/cm2 - 6 minutes fMRI BOLD scan with eight 0.5s excitation pulses at 2880mW/cm2 - 6 minutes fMRI BOLD scan with eight 0.5s excitation pulses at 5760mW/cm2 - 6 minutes MPRAGE high resolution scan - 9 minutes fMRI BOLD scan with two 30s inhibition pulses - 6 minutes This will be done at the lowest intensity at which activation was seen. Diffusion tensor imaging (DTI) scan - 15 minutes

Reliability and repeatability of fMRI scanning will be ensured. For the activation related work in the present experiments, centroids of activation will be identified using the canonical general linear model (GLM) methods in common use, thresholding regions using z statistics calculated under the analysis stream embodied in FSL. In comparing signals across trials and stimulus conditions the extent of suprathreshold activity will not be evaluated, but the activation magnitude, essentially the slope of regression ("beta weights") derived from the GLM will be evaluated. The investigators have shown that, by comparison to the threshold extents, this measure is highly reliable and repeatable across not only individual scans, but over multi-day scanning sessions. Additional information regarding fMRI image processing and analysis is provided in Appendix A.

Additionally, MRI anisotropy images and diffusion tensor maps of the brain area following resection will be performed (using a 3 Tesla MRI system).

Heart Rate and Blood Pressure Monitoring The patient will be affixed with a heart rate monitor. A periodic blood pressure check will be performed if the heart rate increases more than 30% during or immediately after sonication. The investigators' lab has the capacity to measure those parameters in MRI. If the patient's blood pressure has also increased more than 10% then they will be withdrawn from the study.

EEG Monitoring Routine electrode electroencephalography (EEG) recorded immediately before and after the LIFUP sonication session. Recording will last approximately 60 minutes.

A 30-minute awake EEG using scalp electrodes placed according to the International 10-20 System of electrode placement will be performed immediately before and immediately after the LIFUP treatment.

A digital 21 channel EEG will collect data. The number of epileptiform discharges during a 30-minute period before and a 30-minute period after LIFUP will be counted. The investigator responsible for counting epileptiform discharges will be blinded as to which record is pre- and post-treatment. Epileptiform Discharge frequency (DF) before and after the treatment sessions will be determined, and the percent-change in DF (d%-DF) will be calculated.

Data Collection Symptoms reported by the participant during a treatment session will be recorded on a standard worksheet for that treatment session. A standard worksheet for the neurological exam will be filled out by a neurologist. The BSI is a self-administered questionnaire. The neuropsychiatric battery results will be performed and recorded by a neurologist trained to do so by a neuropsychologist. All demographic and neuropsychological data will be entered into a database for further analysis.

Histology After surgical resection of the anterior temporal lobe, histology will be performed on the resected tissue to look for evidence of tissue injury not characteristic of temporal lobe epilepsy or previously identified on the routine brain MRI. The investigators' neuropathologist (Dr. Yong) will assess irreversible disruption to the blood brain barrier, apoptosis and ischemia in the specimens, as recommended by the FDA. Dr. Yong believes that the investigators will be able to differentiate the damage produced by LIFUP vs. usual epilepsy related changes in the temporal lobe. Ultrasound damage is characterized primarily by apoptosis, disruption of the blood-brain barrier and coagulation, and, at very high intensities, hemorrhage. In contrast, standard epilepsy related changes are more confined to glial abnormalities, sclerosis, dilated perivascular spaces and minor inflammatory changes.

Dr. Yong will perform the histology experiments. Tissue from ultrasound-treated and control (untreated) areas of brain will be fixed in 10% formalin for 12-16 hours and formalin-fixed paraffin embedded (FFPE) blocks will be prepared. Five micron FFPE sections will be cut and stained with hematoxylin and eosin to evaluate for histologic evidence of ischemia, apoptosis, and hemorrhage in treated and in control tissues. In addition, a Terminal deoxynucleotidyl transferase (dUTP) nick end labeling (TUNEL) assay (ApopTag® Plus Peroxidase In Situ Apoptosis Kit, Chemicon, Temecula, CA) will be utilized to detect apoptosis in treated and control tissues. Portions of brain from ultrasound-treated and control areas will be fixed in glutaraldehyde and epon sections will be prepared for electron microscopy. Electron microscopy will be performed to evaluate the blood brain barrier (including endothelium and associated glia) of the microvasculature.

One potential difficulty in analysis arises when acute traumatic and ischemic changes occur during the operation. According to the investigators' epilepsy team these occurrences are rare and the investigators will exclude the patients that have excessive trauma during the brain resection. The specimen from the sonication location will be compared to specimens that did not undergo sonication from the same patient and as well as un-sonicated control patients.

Tissue-Marking Dye will be used to permanently mark the margins of the resected tissue area which will not be affected by the treatment (control tissue) and to mark the margins of each resected tissue area affected by the treatment. Appropriate markings will designate the exposed treatment condition to which the tissue was subjected. Although markings will be used to designate excised tissue, prepared slides of the tissue will contain coded labels so that an independent pathologist examining the sample will remain blinded to the origin of the sample.

Interim Safety Analysis The data will be analyzed after the first subject in order to determine subsequent treatment paradigm in the next 2 subjects. After the first participant, histology data will also be analyzed by the investigator. If the participant shows histological damage in the a category (i.e. apoptosis, irreversible blood brain barrier (BBB) disruption, ischemia) at a given intensity then the investigators will continue with the next cohort of 2 participants, but the investigators will no longer use that intensity, or higher intensities. If more than one participant shows histological damage in the same category at the lowest intensity (720mW/cm2), then the study will be stopped.

Biostatistical Analysis

Statistical analyses will be performed using SAS® v9.3 or higher (SAS Institute, Cary NC, USA).

If any statistical tests will be performed, they will be two-sided. The required significance level of findings will be equal to or lower than 5%. Where confidence limits are appropriate, the confidence level will be 95%.

All statistical analyses of safety and performance measures will be descriptive in nature. Continuous variables will be summarized by a mean, standard deviation, minimum, median and maximum, and categorical variables by a count and percentage. Confidence intervals will be provided where relevant.

If multiple evaluations are taken in a single patient, statistics described below will be appropriately modified to accommodate the within patient correlation.

Demographic, medical and clinical history variables will be tabulated. Continuous variables will be summarized by a mean, standard deviation, minimum, median and maximum, and categorical variables by a count and percentage.

The numbers of patients who were enrolled and completed each visit of the study will be provided, as well as the reasons for all enrollment discontinuations, grouped by major reason (e.g., lost to follow-up, adverse event). A list of discontinued patients, protocol deviations, and patients excluded from the efficacy analysis will be provided as well.

Histological results in the resected tissue of the anterior temporal lobe will be presented.

Comparison of all neurological assessment scores at the pre-treatment visit and at the post-treatment visit will be presented.

Comparison of the number of epileptiform discharges and Epileptiform Discharge frequency (DF) during a 30-minute period before and a 30-minute period after LIFUP will be presented.

Change in BOLD signal during or after LIFUP sonication will be presented.

Subjects who do not have valid data for the efficacy measures will be treated as missing values. No imputation is planned.

Risks and Discomforts

Some participants might feel uncomfortable answering questions in the psychiatric evaluation during the first study visit. They will not be forced to answer if they do not wish to answer any particular question. Additional the psychiatric evaluations being used solicit active suicidal ideation. Should a participant answer "Yes" to questions B5 to B11 on the MINI, or response box 3 or 4 on question 9 of the BDI-II, or any other spontaneous expression of suicidality, the licensed physician investigator administer the evaluations will then triage to a higher level of psychiatric care.

There are no known or foreseeable risks or side effects associated with conventional EEG recordings.

MRI is a safe and painless procedure for most people and there are no known health risks associated with scanning. The loud gradient noise of the MRI scanner could cause hearing damage if no hearing protection was used. All subjects will be required to wear earplugs to ensure that scanner noise is reduced to safe levels. Careful screening for contra-indicators (e.g., electrically, magnetically, or mechanically activated implants) will be conducted before scanning. MRI sessions, the examiner and the technologist performing the measurements will maintain voice contact with participants for the entire time that they are in the measurement device and repeatedly inquire if they are well and comfortable. If a subject becomes claustrophobic or uncomfortable during scanning, s/he will immediately be taken out of the measurement device and the experimental session will be discontinued.

A subject will be withdrawn from the study for any of the following reasons:

The investigator decides that the subject should be withdrawn due to safety issues The patient withdraws consent.

If a subject withdraws before completing the study, the reason for withdrawal will be documented on the case report form (CRF).

Potential Benefits

Participation in this study has no direct benefit to the participants. It is hoped that future psychiatric patients might benefit if the results of the study help to advance our understanding of brain function. The MRI scan is not a diagnostic procedure. However, if the investigators believe that an abnormality in a MRI scan has been found a physician, who is trained in the reading of MRI scans, will be asked to assist. If the physician determines that there is an abnormality (e.g., tumor) in a MRI scan, he will then contact the participant and provide him or her with assistance for further follow-up of such an abnormality.

Monitoring and Quality Assurance

In accordance with Massachusetts General Hospital (MGH) guidelines, and as outlined to the participants in the consent form, their confidentiality will be ensured throughout the study. All data will be identified by code numbers only and no description of individual patients will be included in any publication. Participants will be told that they should only write down their code number on the questionnaires but not any identifying information such as name and demographic data. Any adverse event will be reported according to the reporting guidelines. Data will be stored in a locked file cabinet in the Psychiatric Neuroscience Program at Charlestown Navy Yard(CNY) 149 at MGH. Additionally, data will be stored electronically and on a public website, all in de-identified format.

Study Completion/Termination A subject will be considered to have completed the study if he/she completed the MRI procedure and subsequently underwent temporal lobe surgery.

The study is considered completed with the last visit of the last subject undergoing the study. The sponsor reserves the right to close the investigational site or terminate the study at any time. The investigational site will be closed upon study completion.

The investigators will be trained in the use of the BrainSonix BX Pulsar 1002 device by the sponsor. The sponsor will select an investigator who is knowledgeable and experienced with the temporal lobe resection procedures performed as part of this study.

Protocol Modifications The investigator will not modify this protocol without a formal amendment. Protocol amendments must not be implemented without prior International Electrotechnical Commission (IEC)/Institutional Review Board (IRB) approval, except when necessary to eliminate immediate hazards to the subjects in which case the amendment must be promptly submitted to the IEC/IRB and relevant competent authority.

Protocol Deviations The investigator will contact the sponsor representative by fax or telephone regarding any situations requiring a deviation from the protocol. If possible, contact will be made before implementing any deviation from the protocol. In all cases contact with the sponsor must be made as soon as possible in order to discuss the situation and agree on an appropriate course of action. The data recorded in the CRF and source document will reflect any deviation from the protocol, and the source documents will describe this deviation and the circumstances requiring it. Additionally, a protocol deviation form will be completed with a detailed explanation of the protocol deviation.

Subjects Confidentiality Volunteers' name and personal data will remain confidential and will not be published in any way.

Case Report Form Completion All data relating to the study will be recorded in CRFs. Data will be entered into CRFs in English only. The CRFs are to be completed at the time of the subject's visit, so that they always reflect the latest observations on the subjects participating in the study. The investigator must verify that all data entries in the CRFs are accurate and correct.