MAYO CLINIC NEUROSCIENCE UPDATE 3

volume 1 NEUROSCIENCES UPDATE number 2 2004 NEUROLOGIC SURGERY AND CLINICAL NEUROLOGY NEWS FROM MAYO CLINIC ROCHESTER

Treatment Options for Vestibular

Acoustic neuromas, The selection of treatment is highly more appropriately individualized—and sometimes subject to called vestibular controversy. The first option is simply to , are observe and note the patient's progress with a benign tumors follow-up MRI and a hearing test in 6 months. that arise from This is particularly true for patients older than overproduction of 65 years who have small tumors. perineural Schwann For patients younger than 65 years who have cells. They account small tumors and good hearing, there are 2 main for 6% to 8% of all options. First is stereotactic radiosurgery, a primary intracranial 1-day, outpatient, focused radiation treatment. Colin L. W. Driscoll, MD, and tumors. Within the This treatment does not destroy or remove the Michael J. Link, MD cerebellopontine tumor. Rather, it stops or slows its growth. At angle they represent 80% of tumors. The incidence Mayo Clinic, more than 300 patients have been of vestibular schwannomas is hard to estimate, treated for vestibular schwannoma using but it is probably somewhere between 10 and 15 Gamma Knife stereotactic radiosurgery. The per 1 million population. overall results are very good, with an expected The tumors typically present in patients greater than 95% chance of long-term tumor between 40 and 50 years old. But they can occur in control. The risk of facial weakness is less than 1%. children and occasionally in patients in their 80s. Second is an open surgical approach (Figure 1). Irrespective of the age of the patient, common Mayo Clinic neurologic surgeons operate on all symptoms include unilateral , , sizes of tumors, ranging from a few millimeters to and impairment or loss of balance. Hearing loss greater than 6 cm. If the tumor measures less that is bilateral and symmetric is unlikely to be than 2 cm and the patient has useful hearing in caused by a vestibular schwannoma. the affected ear, an approach that preserves Says otorhinolargyngologist Colin L. W. hearing is attempted—either a retrosigmoid Driscoll, MD: “Irrespective of the age of the approach or a middle fossa approach. The goal of patient, the most common presenting symptom Inside This Issue is gradual or sudden-onset unilateral hearing loss and tinnitus. More rarely, patients may Surgical Management experience or mild imbalance.” Adds his of Brain Tumors That colleague, neurosurgeon Michael J. Link, MD: Cause Epilepsy ...... 2 “If a vestibular schwannoma becomes large Interdisciplinary Brachial enough, it can produce facial numbness, severe Plexus Clinic Uses Novel ataxia, and even dysphagia by impinging on the Approaches to Attempt to nerves that mediate those functions.” Restore Hand Function . . . 4 Diagnosis and Treatment Options Carotid Angioplasty With The best modality available to confirm the Stent Placement ...... 6 diagnosis of vestibular schwannoma is MRI of the head, with and without contrast. The tumor Figure 1. Left, Preoperative axial T1-weighted image with Physician Directory ...... 8 gadolinium shows a 2.5-cm right vestibular schwannoma. is almost always seen as a brightly enhancing Right, Postoperative axial T1-weighted image with lesion in the cerebellopontine angle that enlarges gadolinium 2 years after tumor resection shows and extends to the internal auditory canal. complete tumor removal with no evidence of recurrence.

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the surgery is to remove all the tumor, thus curing Knife radiosurgery if it shows growth on the patient and preserving useful hearing without future imaging.” adding new neurologic deficits. A neurosurgical and otorhinolarygologic SCHWANNOMA CLINIC Depending on the size and configuration of team performs all operations for vestibular CONSULTANTS the tumor, hearing preservation ranges between schwannomas at Mayo Clinic. These specialists Neurosurgery 10% and 50%. The risk of facial nerve weakness have extensive experience treating tumors of Michael J. Link, MD varies from less than 1% in patients with very this type and a good collaborative approach to Otorhinolaryngology small tumors to 20% to 25% in patients with very treating these patients. The alliance of advanced Colin L. W. Driscoll, MD large tumors. The risk of other surgical specialties working together—neurosurgeons, Charles W. Beatty, MD complications is less than 1%, and the typical otorhinolaryngologists, radiation oncologists— Stereotactic Radiosurgery hospital stay is 3 to 5 days. is a hallmark of the Mayo Clinic approach to the Michael J. Link, MD If the patient does not have useful hearing, a treatment of vestibular schwannomas. Says Dr Bruce E. Pollock, MD translabyrinthine approach may be recommended. Link: “Patients benefit tremendously from Neuro-oncology This involves operating through the inner ear, preoperative consultation by all members of the Terrence L. Cascino, MD and subsequently no hearing is preserved in that team so they have a thorough understanding of Julie E. Hammack, MD ear. This approach has some benefit in that it the treatment options from the very beginning.” David W. Kimmel, MD Daniel H. Lachance, MD exposes the internal auditory Brian P. O'Neill, MD canal well, which tends to Joon H. Uhm, MD make this portion of removal Radiation Oncology of the tumor easier. Paul D. Brown, MD There is a third open Robert L. Foote, MD surgery scenario as well: Yolanda I. Garces, MD Paula J. Schomberg, MD subtotal resection (Figure 2). Scott L. Stafford, MD Says Dr Link: “In some cases we may elect to do subtotal Audiology Christopher D. Bauch, PhD resection on a very large Jodi A. Cook, PhD tumor. We may elect to leave a small portion of the tumor attached to the facial Figure 2. Left, Preoperative coronal T1-weighted image with gadolinium shows a nerve to avoid inducing very large, 4.5-cm right vestibular schwannoma with severe compression of the new facial weakness after brain stem and cerebellum and moderate obstructive hydrocephalus. Right, Coronal T1-weighted image with gadolinium 3 months postoperatively shows a surgery. Then, once we small tumor remnant along the course of the right facial nerve. Hydrocephalus have reduced the tumor to has resolved, and the patient has normal facial nerve function. The tumor an acceptable size, we treat remnant is now a size that could be treated effectively with radiosurgery if it the remnant with Gamma shows signs of growth.

Surgical Management of Brain Tumors That Cause Epilepsy

Brain tumors are among the possible causes of surgery. An estimated 70% of tumors that cause epilepsy, defined as chronic and recurring epilepsy are slow-growing . seizure activity, in both adults and children. Favorable surgical outcomes depend on the Various types of brain tumors can be involved completeness of resection of both the lesion and in seizure generation. Common epilepsy-related the epileptogenic zone involved in seizure tumors arise from glial cells and include low- initiation. Complete resection requires a highly grade gliomas such as pilocytic , skilled, experienced, and integrated surgical ganglioglioma, dysembryoplastic epithelial neuroscience team accustomed to working together tumors, and . These tumors throughout the continuum of care. Individualized are generally slow growing, tend to be benign and care—from presurgical evaluation to planning and well defined, and are successfully removed by executing a specific surgical strategy unique to each

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patient through postoperative care and follow-up—is the hallmark of the Mayo Clinic Epilepsy Center neurosurgical team. EPILEPSY CENTER Because of advances in neuroimaging, CONSULTANTS epilepsy-associated brain tumors are more Neurosurgery easily detected. However, these may not For adults: be visualized by CT scan. MRI is W. Richard Marsh, MD Fredric B. Meyer, MD indispensable for visualizing exact anatomic details of the tumor. Says W. For children: Richard Marsh, MD, Mayo Clinic Corey Raffel, MD neurosurgeon: “Every patient with a Neurology chronic seizure disorder deserves to have MRI scans of left temporal lobe preoperatively (left) and postoperatively Jeffrey W. Britton, MD an MRI scan. If a can be Gregory D. Cascino, MD (right) after successful removal of tumor. Terrence D. Lagerlund, MD identified as a cause of the seizure Cheolsu Shin, MD disorder, good surgical treatment exists.” eloquent areas, surgery proceeds with the patient Elson L. So, MD Adds neuropsychologist Max R. Trenerry, PhD: “In Barbara F. Westmoreland, MD under general anesthesia. Gregory A. Worrell, MD, PhD addition to the anatomic detail that MRI can Precision during the surgery is assured by provide, neuropsychological evaluation helps computer-assisted monitoring. This technology Neuropsychology patients understand the nature and extent of Max R. Trenerry, PhD provides information about the volume, shape, cognitive changes associated with the tumor and and configuration of the tumor and is used to seizure disorder.” identify the margins of the tumor, which may not be Evaluating the Epileptic Patient apparent under direct visualization. With this At Mayo Clinic, a patient seeking care for understanding of the physical space within the brain-tumor-caused epilepsy sees at least patient's brain in which the tumor exists, surgeons 3 specialists from the neurosciences team. can excise it successfully and thoroughly—thus Consultation with a neurologist includes careful increasing the likelihood that seizures will cease history taking and a thorough examination. A once the tumor and the epileptogenic zone are neurosurgeon discusses details of the various removed. In the future, intraoperative MRI will be surgical approaches, including recovery, risks, and used to confirm complete tumor removal. benefits. Consultation with a neuropsychologist Results and detailed neuropsychological testing assess The usual hospital stay after tumor removal is 4 the potential effects of surgery on cognitive days. Most patients can resume full activity within a abilities, including intelligence, memory, attention, few months. Some patients are able to stop taking and reasoning. their antiepileptic medications within the first Preoperative testing includes MRI as well as several years after surgery. About 70% of epileptic prolonged EEG recordings to co-localize the patients with tumors and seizures become seizure- patient’s seizure onset with identified tumors. free as a result of brain surgery. Occasionally, patients need intracranial monitoring to localize the extent of the epileptogenic zone Complications and Risks around the area of the identified tumor. Complications and risks are unique to each This monitoring can include the insertion patient. They depend on the area of brain involved of either deep brain or surface electrodes and the exact type of tumor and will be discussed over the portion of normal brain in the in detail with the patient by the neuroscience team. region of tumor. When to Refer Surgical Options If a patient has an abnormal MRI showing If the tumor is near eloquent areas of a benign tumor, he or she should be referred as brain—such as primary language areas or early as possible. This is especially true for primary motor or sensory areas—it is pediatric patients. Says Dr Marsh: “With a child usually performed with the patient who is in a learning-growth-development phase, sedated but awake to minimize the risk of seizures adversely affect development. If there is neurologic deficit. an identifiable, curable cause, treatment is best undertaken sooner to get the child back on an W. Richard Marsh MD, and If tumors are located in tissue outside Max R. Trenerry, PhD ascending track.”

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Interdisciplinary Brachial Plexus Clinic Uses Novel Approaches to Attempt to Restore Hand Function

The brachial plexus is a complex network of across medical and surgical specialties clearly interconnecting nerves that innervate the arm enhance the care, outcome, and satisfaction of our from the shoulder to the hand. The C5 through Brachial Plexus Clinic patients.” C8 and T1 spinal nerve roots form the basis of Mayo Clinic's Interdisciplinary the brachial plexus. Brachial Plexus Clinic Injury and lesions to the brachial plexus are The interdisciplinary Brachial Plexus Clinic at fairly common and arise from a variety of causes. Mayo Clinic in Rochester addresses the complex Traumatic lesions are typically caused by problems of patients who have brachial plexus high-speed motor vehicle accidents, such as those lesions. Specialists from several areas—neurosurgery, involving motorcycles and snowmobiles. Perinatal orthopedic surgery, neurology, radiology, physical cases occur in 1 in 2,000 births and are often medicine and rehabilitation, physical and related to shoulder dystocia. Other causes include occupational therapy—work cooperatively to tumors, irradiation, and nerve entrapment. design a treatment and recovery plan that is unique In traumatic lesions, critical motor function to each patient. It is the mission of the Brachial in the shoulder, elbow, wrist, and hand may Plexus Clinic to help patients recover as much pain- be lost, and sensation in the fingers impaired. free function and quality of life as possible. Incapacitating pain may also result from stretching The team of surgeons that evaluates each or rupture of the nerves of the brachial plexus patient also operates together. Having performed or avulsion of the nerves from the spinal cord. more than 100 procedures in 2003 alone Lesions in the upper trunk (C5 and C6) result in (including 25 contralateral C7 transfers and the loss of shoulder and elbow flexion, whereas 30 free-functioning muscle transfers in the past injuries to the lower trunk (C8 and T1) impair 2 years), this team has extensive experience and hand function. Injuries to the complete brachial BRACHIAL PLEXUS expertise to provide state-of-the-art care for CLINIC CONSULTANTS plexus paralyze the entire upper limb. patients with brachial plexus injuries. Whatever the cause, these injuries can inflict Neurosurgery Says Dr Harper: “The multidisciplinary severe disability in the shoulder, elbow, and hand. Robert J. Spinner, MD approach is absolutely essential when evaluating “In addition to the physical problems, patients and treating patients with complicated brachial Orthopedic Surgery may also have considerable psychological distress Allen T. Bishop, MD plexopathies. Each patient is evaluated by a and economic hardship,” says neurosurgeon Alexander Y. Shin, MD neurologist with a special interest in peripheral Robert J. Spinner, MD. “The good news is that nerve disorders. The same team of neurologists Neurology recent advances in the diagnosis and operative Brian A. Crum, MD performs all necessary electrodiagnostic studies— management and the depth of our multidisciplinary P. James B. Dyck, MD both preoperatively and during surgery—to help C. Michel Harper, MD Brachial Plexus Clinic neurosciences team all work the surgical team make critical decisions Christopher J. Klein, MD together to improve function and ease the patient's Eric J. Sorenson, MD regarding localization, prognosis, and treatment psychological distress.” options for the patient.” Adds neurologist C. Michel Harper, MD: “Communication and coordination of patient care Treatment Options The diagnosis of brachial plexus injury can be established soon after injury. Evidence of complete root avulsion indicates early surgical intervention is necessary, and the sooner it is undertaken, the better the outcome. Waiting longer than 6 months for surgery is not advisable because the cumulative effects over time of muscle atrophy, motor end plate degeneration, and neuronal death contribute to inferior outcomes. Surgery Surgical options include neurolysis for neuroma Alexander Y. Shin, MD, Allen T. Bishop, MD, and Robert J. Spinner, MD in continuity, nerve repair for lacerations, and

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nerve grafting to bridge gaps that result from Surgeons may direct nerve fibers to a specific traumatic ruptures, tumor excision, or severe motor or sensory “target,” improving chances for stretch lesions (which do not conduct impulses recovery of function. across the lesion). Nerve regeneration is slow, Potential nerve transfers include the spinal however, occurring at a rate of approximately accessory nerve, intercostal motor and sensory 1 inch per month. nerves, and the phrenic nerve. In addition, the Nerve Transfers Mayo Clinic team also uses the contralateral C7 When direct nerve grafting cannot be performed transfer from the opposite (uninjured) side (Figure or is less likely to provide a satisfactory result, 1). Transferring a part of the uninjured C7 nerve transfer of “expendable” uninjured nerves allows root, usually combined with a vascularized nerve the rapid recovery of key muscles. Nerves can be graft, provides the possibility of restoring grasp moved from an uninjured portion of the brachial function in patients with total plexus avulsion. plexus or from a number of other sites to be used In a patient with an upper trunk injury, other for recovery of both motor and sensory functions. innovative techniques that are done closer to the Injured side Normal side

A

D B

E C

Figure 1. Half the C7 nerve from the brachial plexus on the normal side is selected (A) and used (B) to power the injured side. A vascularized ulnar nerve graft from the injured side is reversed and connected to the donor C7 nerve on the normal side (C). The other end of the ulnar nerve graft is then connected to the median nerve on the injured side (D and E). This complex technique potentially allows patients with severe brachial plexus injuries to regain sensation in the hand and movement in the fingers on the injured side.

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target muscle may be used to improve function. For example, a fascicle of the ulnar nerve or the median nerve may be used to reinnervate the biceps muscle; in addition, one of the nerve branches supplying (a part of) the triceps may be used to reinnervate the deltoid muscle. Muscle Transfers Another advanced method is the microsurgical transfer of a healthy muscle. With circulation restored and nerve repairs performed in the arm, the muscle transfer can provide needed motor function when delay in or previous unsuccessful treatment has resulted in irreversible muscle atrophy in the arm or when improvement of hand function is desired. To do this, the surgical team transfers an expendable muscle, such as the gracilis muscle from the thigh, along with its nerve and blood supply, to animate the elbow, wrist, and hand (Figure 2). Collectively, these methods often Figure 2. This illustration demonstrates the restore shoulder stability, limited but useful technique for free vascularized muscle transfer shoulder abduction, full elbow flexion, and, in some for finger flexion. Gracilis muscle is harvested from the thigh. An artery, vein, and nerve are patients, hand function and protective sensation. repaired. The transferred gracilis muscle is For information about the Brachial Plexus attached to the second rib, passed under the Clinic or to refer patients for evaluation, contact skin, and connected to muscles in the forearm 507-538-1988. that control finger flexion.

Carotid Angioplasty With Stent Placement

Carotid angioplasty with stent (CAS) placement says neurologist Robert D. Brown, Jr, MD. is an emerging alternative to carotid endarterectomy Adds Harry J. Cloft, MD, PhD, neuroradiologist: for the treatment of patients with carotid artery “The protocol has been highly successful in occlusive disease. Mayo Clinic neuroradiologists allowing us to select patients carefully and began using it in 1996 for patients at high risk appropriately as we move forward with this for surgery. emerging technology.” “The Cerebrovascular Clinic in the Department Indications for CAS Placement of Neurology has a multidisciplinary CAS Patients who have a severe carotid artery placement protocol in which a vascular narrowing are candidates for CAS placement, neurologist, an interventionalist, and a surgeon— especially those who have had symptoms such either a vascular surgeon or a neurosurgeon—meet as transient ischemic attack or cerebral infarction with the patient to help clarify the best caused by that narrowing. “However, we also treatment approach. Cardiology colleagues may occasionally use CAS placement to treat severe also be involved if the patient has cardiac carotid stenosis even though a patient has had no symptoms. This is not uncommon, since so symptoms, just as we may recommend carotid many patients with carotid occlusive disease endarterectomy for asymptomatic carotid disease,'' also have coronary artery occlusive disease,” Dr Brown says.

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How CAS Placement Works Most patients arrive at the Cerebrovascular Clinic after carotid CEREBROVASCULAR ultrasonography or MR angiography CLINIC CONSULTANTS has shown narrowing of the carotid Vascular Neurology artery. After thoroughly examining Robert D. Brown, Jr, MD the patient, the multidisciplinary Bruce A. Evans, MD neurosciences team members Kelly D. Flemming MD Jimmy R. Fulgham, MD decide whether CAS placement Edward M. Manno, MD is the appropriate treatment. If Irene Meisser, MD it is, the patient proceeds to the George W. Petty, MD David O. Wiebers, MD interventional neuroradiology suite Eelco F. M. Wijdicks, MD in Saint Marys Hospital for further evaluation. Vascular Neurosurgery John L. D. Atkinson, MD The patient is sedated but awake, Michael J. Link, MD and a small plastic catheter is Fredric B. Meyer, MD inserted in a groin artery and Left, Preoperative image of narrowed carotid artery. Right, Postoperative David G. Piepgras, MD tracked through the aorta to the image showing stent in place and open artery after CAS placement. Interventional carotid arteries. Next, contrast Neuroradiology material is injected to delineate the anatomy. If conventional surgery. The outcomes of these Harry J. Cloft, MD, PhD David F. Kallmes, MD the angiogram confirms severe narrowing that early cases were excellent and the risk of stroke could be best treated with CAS placement, then and death was extremely low. Because these Vascular Surgery the procedure begins. measures of success were so similar to the Timothy M. Sullivan, MD First, a protection device may be deployed standard treatment of carotid endarterectomy, distally in the carotid artery—this device the use of CAS placement was cautiously and functions something like a minute net umbrella carefully expanded. to catch material that may break free when the Since then, Mayo Clinic experience with CAS angioplasty is performed. Then the angioplasty placement suggests that, when performed by an balloon is brought across the plaque and experienced, multispecialty team on carefully inflated to push the plaque aside, thus reducing selected patients, the procedure is approximately arterial narrowing. The stent—a small metallic equal to carotid endarterectomy in terms of scaffolding device—is brought up to keep the effectiveness, risks, and complications. material pushed aside so the artery remains Future Directions open. The procedure ends with withdrawal of The National Institutes of Health has selected the distal protection device and the catheter. Mayo Clinic to participate with 25 US medical Typically, the patient is hospitalized for centers in the formal evaluation of CAS 1 day. Aftercare involves taking daily clopidogrel placement in the Carotid Revascularization and aspirin for 1 month to prevent blood clots Endarterectomy Versus Stent Trial (CREST). from forming at the CAS site and then aspirin The goal of CREST is to determine how CAS alone indefinitely thereafter. Mayo Clinic placement compares with carotid endarterectomy, specialists follow each patient long the standard treatment for carotid artery term, both to assess durability of the stent stenosis. A key question is whether the risk of and to determine whether narrowing recurrent narrowing after CAS placement is as recurs. Follow-up includes annual low as the extremely low risk of recurrent carotid ultrasonography that begins narrowing after carotid endarterectomy. several months after the procedure. CREST will also evaluate the comparative Results, Risks, and Complications risks of stroke associated with CAS placement The concept of CAS placement is a and carotid endarterectomy. Because CAS logical extension of the balloon placement requires the interventionalist stenting used for coronary artery to work within the artery, the possibility disease. Initially, in the early 1990s, exists for stroke during the procedure. Carotid CAS placement was performed on endarterectomy, when performed by an Harry J. Cloft, MD, PhD, and Robert D. Brown, Jr, MD patients who were at high risk for experienced neurosurgeon or vascular surgeon,

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carries a very low risk of stroke. The goal of patients with carotid artery narrowing or the CREST protocols is to determine these occlusion, including those who do not wish to issues conclusively. participate in the CREST study. To find out more Mayo Clinic's Cerebrovascular Clinic is now about participating in CREST or referring a patient accepting enrollees into the CREST study. The for evaluation, call the Cerebrovascular Clinic at Cerebrovascular Clinic also evaluates other 507-284-1588.

PHYSICIAN DIRECTORY

Department of Behavioral Neurology Clinical Neurology Jasper R. Daube, MD Anthony J. Windebank, MD Bradley F. Boeve, MD Andrea C. Adams, MD (regional practice)(amyotrophic (amyotrophic lateral sclerosis) Neurologic Surgery (sleep disorders) (regional practice) lateral sclerosis) Sleep Disorders Neurosurgeons Daniel A. Drubach, MD Patty P. Atkinson, MD Alison M. Emslie-Smith, MD Michael H. Silber, MBChB John L. D. Atkinson, MD Keith A. Josephs, MD (spine disorders) Andrew G. Engel, MD (movement disorders) Eduardo E. Benarroch, MD W. Neath Folger, MD Dudley H. Davis, MD Speech Pathology David S. Knopman, MD (autonomic nervous system) C. Michel Harper, MD William E. Krauss, MD Joseph R. Duffy, PhD Ronald C. Petersen, MD, PhD Bruce R. Krueger, MD (myasthenia gravis) Michael J. Link, MD Edythe Strand, PhD W. Richard Marsh, MD Neeraj Kumar, MD William J. Litchy, MD Cerebrovascular–Critical Care Fredric B. Meyer, MD Bahram Mokri, MD Kathleen M. McEvoy, MD Robert D. Brown, Jr, MD (regional practice)(myasthenia gravis) Department of David G. Piepgras, MD Bruce A. Evans, MD Epilepsy Margherita Milone, MD, PhD Radiology Bruce E. Pollock, MD Jeffrey W. Britton, MD (research) Kelly D. Flemming, MD Interventional Neuroradiology Corey Raffel, MD, PhD Gregory D. Cascino, MD Eric J. Sorenson, MD Jimmy R. Fulgham, MD Harry J. Cloft, MD, PhD Robert J. Spinner, MD (neuro critical care) Terrence D. Lagerlund, MD (amyotrophic lateral sclerosis) David F. Kallmes, MD Edward M. Manno, MD Cheolsu Shin, MD J. Clarke Stevens, MD (neuro critical care) Elson L. So, MD Department of Neuro-oncology Irene Meissner, MD Barbara F. Westmoreland, MD Department of Neurology Terrence L. Cascino, MD George W. Petty, MD (EEG) Laboratory Medicine Julie E. Hammack, MD David O. Wiebers, MD Gregory A. Worrell, MD Autoimmune Neurology Daniel H. Lachance, MD and Pathology Eelco F. M. Wijdicks, MD Vanda A. Lennon, MD, PhD Headache (regional practice) Neuropathology (research) (neuro critical care) J. D. Bartleson, Jr, MD Brian P. O’Neill, MD Caterina Giannini, MD (spine disorders) Joon H. Uhm, MD Joseph E. Parisi, MD David F. Black, MD Cynthia J. Wetmore, MD, PhD Bernd W. Scheithauer, MD MAYO CLINIC Christopher J. Boes, MD Neuro-ophthalmology F. Michael Cutrer, MD Neurosciences Update Shelley A. Cross, MD Jerry W. Swanson, MD Surgical Editor: Robert J. Spinner, MD Neuro-otology and Mayo Clinic also offers Infectious Disease Medical Editor: John H. Noseworthy, MD Ocular Motor Disorders extensive neurologic Allen J. Aksamit, MD surgery and clinical neurology Editorial Board: Bradley F. Boeve, MD, Terrance L. Cascino, Scott D. Eggers, MD services in Jacksonville, MD, Suresh Kotagal, MD, Michael J. Link, MD, Movement Disorders Pediatric Neurology Florida, and Scottsdale, J. Eric Ahlskog, MD, PhD W. Richard Marsh, MD, Fredric B. Meyer, MD, Jeffrey R. Buchhalter, MD Arizona. Brian P. O’Neil, MD, Corey Raffel, MD, PhD James H. Bower, MD (pediatric epilepsy) For patient referral Publication Manager: Carol F. Lammers (regional practice) Suresh Kotagal, MD information for these Robert D. Fealey, MD (pediatric sleep disorders) Art Director: Ronald O. Stucki locations, please contact: (autonomic nervous system) Nancy L. Kuntz, MD Production Designer: Connie Lindstrom Demetrius M. Maraganore, MD (neuromuscular) Departments of Neurology Science Writer: Anne D. Brataas Joseph Y. Matsumoto, MD Kenneth J. Mack, MD and Neurosurgery Manuscript Editor: Jane C. Wiggs, MLA, ELS (pediatric headaches and Media Support Services Contributing Artists: Multiple Sclerosis tic disorders) Mayo Clinic David Factor, Joseph Kane, Erina Kane B. Mark Keegan, MD Deborah L. Renaud, MD 4500 San Pablo Road (regional practice) (metabolic disorders) Jacksonville, FL 32224 Neurosciences Update is written for physicians and should Claudia F. Lucchinetti, MD Duygu Selcen, MD 904-953-2103 be relied upon for medical education purposes only. It does not John H. Noseworthy, MD (neuromuscular) provide a complete overview of the topics covered and should Moses Rodriguez, MD Departments of Neurology not replace the independent judgment of a physician about the Peripheral Nerve Brian G. Weinshenker, MD and Neurologic Surgery appropriateness or risks of a procedure for a given patient. Peter J. Dyck, MD Mayo Clinic Neuromuscular Disease P. James B. Dyck, MD 3400 East Shea Boulevard Charles F. Bolton, MD Christopher J. Klein, MD Scottsdale, AZ 85259 Brian A. Crum, MD Phillip A. Low, MD 480-301-6539 (within (amyotrophic lateral sclerosis, Paola Sandroni, MD, PhD Maricopa County) 200 First Street SW MC5520rev0904 myasthenia gravis) Rochester, Minnesota 55905 Guillermo A. Suarez, MD 866-629-6362 (nationwide) www.mayoclinic.org

© 2004, Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. MAYO, MAYO CLINIC and the triple-shield Mayo logo are trademarks and service marks of MFMER. (Denotes subspecialty interest) The term “regional practice” indicates that the consultant spends a portion of time serving clinics in the Mayo Health System outside Rochester.

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