DOCSLIB.ORG

Reversal of Cerebraldominance Forlanguage

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Reversal of Cerebraldominance Forlanguage J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.49.6.628 on 1 June 1986. Downloaded from Journal of Neurology, Neurosurgery, and Psychiatry 1986;49:628-634 Reversal of cerebral dominance for language and emotion in a corpus callosotomy patient R JOSEPH From the W. Haven V. A. Medical Center, CT UHS/The Chicago Medical School, Chicago, USA SUMMARY A case study of a right-handed individual with epilepsy and brain dysfunction of early onset is described who was found, following callosotomy (sparing the rostrum of the callosum) to be left hemisphere "dominant" for processing and/or expressing emotional and somesthetic information, and right hemisphere "dominant" in regard to the expression and comprehension of language and linguistic stimuli. Hence, a significant reversal in functional representation, due presumably to an injury suffered early in life, was observed. Moreover, following callosotomy the patient demonstrated severe disconnection syndromes in regard to right hand usage, the recognition of emotion, and the production and comprehension of linguistically related information. The left cerebrum appeared to be almost completely without linguistic representation except in regard to emotional language. The possible mechanisms involved in functional sparing and reversed repre- sentation are briefly discussed, and the effects of partial disconnection on the expression of these capacities is presented. Protected by copyright. Approximately 89% of the population are genotypic motor) and also comes hierarchically to represent right handers, of which 90-96% have been estimated functions associated with non-motor (and later matu- to be left hemisphere dominant for expressive and ring) limbic nuclei such as the basolateral division of receptive linguistic functions and fine motor con- the amygdala2' (a nucleus which is highly involved in trol.' 2 In contrast, the right cerebral hemisphere has emotionality).32 - However, because the right cere- been associated with the mediation of visual-spatial, brum matures later, when the brain is damaged early tactile, and emotional information processing, as well in life (as in birth trauma), the left cerebrum is often as the expression and comprehension of prosodic more seriously affected2' such that handedness and (intonation, melody) and emotional language.' -28 language may secondarily come to be subserved by As language (for example vocabulary and gram- the right.36-41 However, in some instances early left mar) and speech are presumably related to (and a hemisphere lesions may instead result in atypical left partial outgrowth of) motor control and handed- hemisphere language localisation. ness,1 2 29 30 it has been argued that the left hemi- Secondary acquisition of language by the right sphere comes to subserve denotative and syntactical hemisphere appears to occur at the expense of certain http://jnnp.bmj.com/ (for example sequential) aspects of linguistic func- right hemisphere capacities (for example visual- tioning because the motor regions ofthe left cerebrum spatial), such that these abilities are reduced.37 3 mature before comparable areas within the right It has been suggested that these functions are hemisphere;21 31 these maturational events appear to sacrificed because capabilities normally subserved by coincide with the development of subcortical and the left competitively "crowd" out later appearing spinal motor nuclei and pathways.2' The right hemi- functions mediated by the right; that is, by growing sphere thus comes secondarily to subserve processes into "vacant" synaptic space.2' 40 In primates, early which are more sensory or receptive in nature structural reorganisation resulting from competitive on September 25, 2021 by guest. (sensory systems in general maturing later than acquisition of functionally "vacant" synaptic space has been well demonstrated.4243 In instances such as these the functions that are displaced via crowd- Address for reprint requests: R Joseph, PhD., Neurobehavioral ing are grossly diminished as structural space is Center, Suite 240, 275 Saratoga Avenue, Santa Clara, CA 95050. presumably committed.4243 Received 17 July 1984 and in final revised form 28 October 1985. Nevertheless, it remains possible, in cases where Accepted 2 November 1985. language has migrated owing to early left cerebral 628 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.49.6.628 on 1 June 1986. Downloaded from Reversal of cerebral dominance 629 injury, that right hemisphere capacities may come to terior cortex with spike and waves in the left fronto- be secondarily subserved by "vacant" undamaged temporal area. Depth electrode EEG monitoring on 16 areas in the left which are no longer committed to channels revealed three independent spike foci. However, language representation. As such, a partial reversal in CT scan appeared normal. Since it was believed that the seizures were spreading between the cerebral hemispheres functional dominance is a strong possibility. via the corpus callosum, callosotomy with sparing of the In the following case, a right-handed individual rostrum and anterior commisures was performed (by Dr with a brain injury and dysfunction ofearly onset was Dennis Spencer of the Yale University Dept of Surgery). found to be right hemisphere dominant for language Prior to surgery assessment of hemisphere specialisation (as determined via dichotic listening and sodium for receptive linguistic functioning was assessed and also amytal studies). Within two weeks of callosotomy determined via dichotic listening (see Methods and Results). (performed to control intractable seizures) it was Vocabulary, word knowledge, verbal abstract reasoning, determined that his left hemisphere was "dominant" and verbal judgement were determined to be within average for processing and/or expressing emotional and tac- (normal) limits. A significant left ear dominance for dichotically presented verbal stimuli was also established. tile information but had little or no capacity for This dominance markedly increased following callosotomy. performing expressive language related tasks. For Intracarotid sodium amytal ("Wada test") injections example, although formerly strongly right hand confirmed right hemisphere dominance for speech. No dominant in regard to most forms of motor activity expressive abilities were demonstrated following the right including writing, following callosotomy he was able hemisphere injection, indicating that the left hemisphere of to use this hand for writing only with great difficulty. this patient was unable to talk. Hence, right hemisphere In contrast, when requested to write with the left hand dominance for both receptive and expressive language was he at first refused stating that it was "impossible" but indicated. with considerable surprise discovered that he could Immediately following surgery the patient was mute and unable to himself This condition with ease. express linguistically. rap- indeed write idly cleared over the next several days. When evaluated 2 Based on these and related findings, this unique weeks later, PC complained ofdecreased sensation in the left individual also appears to be significantly different extremities (which was confirmed via neurological and neu- Protected by copyright. from some callosotomy patients, who, following ropsychological evaluation), and decreased motor control brain bisection, subsequently developed some right over the right extremities. In contrast, sensation was ade- hemisphere language capabilities.44 In addition, quately appreciated when applied to the right side and he however, when this patient was requested to write had no difficulty with left sided motor control. The Boston emotional words, the right hand (in these instances Diagnostic Aphasia battery was administered and normal only) "regained" its superiority whereas his left hand functioning determined. Nevertheless, the patient com- plained of a disturbance in his ability to write or making his performed poorly when presented with emotional formerly dominant right hand "do what I want it to". items. Perceptual-spatial skills were also found to be Attempts at writing were characterised by frequent erasures, moderately reduced. hesitations, the production and crossing out of incorrect let- ters, misspellings, etc: "I know what letters I want, but I History and preoperative evaluation can't make my (right) hand write them". When asked to use his left hand PC at first declined protesting he could not. It PC (partial callosotomy), a 20-year-old right hand dominant was (to his great surprise) the discovery that he could use the Caucasian male, was a product of a term pregnancy with a left without difficulty, whereas when presented with emo- difficult high forceps delivery and began having epileptic tional words the right hand suddenly regained its capacity to seizures at age 8 years characterised by staring, write and spell correctly, which led to the present http://jnnp.bmj.com/ unresponsiveness, drooling, and picking at his clothes. These investigation. would last seconds to minutes with 15-30 minutes post-ictal It is important to emphasise that conceptual, intellectual, confusion. PC experienced 9-15 seizures per month. and linguistic functioning was determined (pre-operatively) Preoperative examination indicated that PC performed to be within average limits. The patient was literate, without best with his right hand across all motor-related tasks dysphasic disturbances, and of normal personality. whereas he employed
Load more

Recommended publications
  • Corpus Callosotomy Outcomes in Paediatric Patients
    CORPUS CALLOSOTOMY OUTCOMES IN PAEDIATRIC PATIENTS David Graham Children’s Hospital at Westmead Clinical School Sydney Medical School University of Sydney Supervisor: Russell C Dale, MBChB MSc PhD MRPCH FRCP Co-Supervisors: Deepak Gill, BSc MBBS FRCP Martin M Tisdall, MBBS BA MA MD FRCS This dissertation is submitted for total fulfilment of the degree of Master of Philosophy in Medicine March 2018 Corpus Callosotomy Outcomes in Paediatric Patients David Graham - March 2018 Corpus Callosotomy Outcomes in Paediatric Patients For Kristin, Isadora, and Oscar David Graham - March 2018 Corpus Callosotomy Outcomes in Paediatric Patients David Graham - March 2018 Corpus Callosotomy Outcomes in Paediatric Patients Perhaps no disease has been treated with more perfect empiricism on the one hand, or more rigid rationalism on the other than has epilepsy. John Russell Reynolds, 1861 David Graham - March 2018 Corpus Callosotomy Outcomes in Paediatric Patients David Graham - March 2018 Corpus Callosotomy Outcomes in Paediatric Patients – David Graham DECLARATION This dissertation is the result of my own work and includes nothing that is the outcome of work done in collaboration except where specifically indicated in the text. It has not been previously submitted, in part or whole, to any university of institution for any degree, diploma, or other qualification. The work presented within this thesis has resulted in one paper that has been published in the peer-review literature: Chapters 2-3, Appendix C: Graham D, Gill D, Dale RC, Tisdall MM, for the Corpus Callosotomy Outcomes Study Group. Seizure outcome after corpus callosotomy in a large pediatric series. Developmental Medicine and Child Neurology; doi: 10.1111/dmcn.13592 The work has also resulted in one international conference podium presentation, one local conference podium presentation, and one international conference poster: Graham D, Barnes N, Kothur K, Tahir Z, Dexter M, Cross JH, Varadkar S, Gill D, Dale RC, Tisdall MM, Harkness W.
    [Show full text]
  • Mapping Language Dominance Through the Lens of the Wada Test
    NEUROSURGICAL FOCUS Neurosurg Focus 47 (3):E5, 2019 Mapping language dominance through the lens of the Wada test Bornali Kundu, MD, PhD, John D. Rolston, MD, PhD, and Ramesh Grandhi, MD Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah The sodium amytal test, or Wada test, named after Juhn Wada, has remained a pillar of presurgical planning and is used to identify the laterality of the dominant language and memory areas in the brain. What is perhaps less well known is that the original intent of the test was to abort seizure activity from an affected hemisphere and also to protect that hemi- sphere from the effects of electroconvulsive treatment. Some 80 years after Paul Broca described the frontal operculum as an essential area of expressive language and well before the age of MRI, Wada used the test to determine language dominance. The test was later adopted to study hemispheric memory dominance but was met with less consistent suc- cess because of the vascular anatomy of the mesial temporal structures. With the advent of functional MRI, the use of the Wada test has narrowed to application in select patients. The concept of selectively inhibiting part of the brain to de- termine its function, however, remains crucial to understanding brain function. In this review, the authors discuss the rise and fall of the Wada test, an important historical example of the innovation of clinicians in neuroscience. https://thejns.org/doi/abs/10.3171/2019.6.FOCUS19346 KEYWORDS Wada test; language dominance; laterality; memory; epilepsy The removal of a tumor at the cost of the patient’s speech is mined by family history or could be “acquired” second- scarcely an accomplishment on which to congratulate oneself.
    [Show full text]
  • Preservation of Electrophysiological Functional Connectivity After Partial Corpus Callosotomy: Case Report
    CASE REPORT J Neurosurg Pediatr 22:214–219, 2018 Preservation of electrophysiological functional connectivity after partial corpus callosotomy: case report Kaitlyn Casimo, BA,1,2 Fabio Grassia, MD,3 Sandra L. Poliachik, PhD,3–5 Edward Novotny, MD,6,7 Andrew Poliakov, PhD,3,4 and Jeffrey G. Ojemann, MD1,2,8 1Graduate Program in Neuroscience and 2Center for Sensorimotor Neural Engineering, University of Washington, Seattle, Washington; 3Department of Neurosurgery, University of Milan, San Gerardo Hospital, Monza, Italy; and 4Department of Radiology, 5Center for Clinical and Translational Research, 6Department of Neurology, 7Center for Integrated Brain Research, and 8Department of Neurosurgery, Seattle Children’s Hospital, Seattle, Washington Prior studies of functional connectivity following callosotomy have disagreed in the observed effects on interhemispheric functional connectivity. These connectivity studies, in multiple electrophysiological methods and functional MRI, have found conflicting reductions in connectivity or patterns resembling typical individuals. The authors examined a case of partial anterior corpus callosum connection, where pairs of bilateral electrocorticographic electrodes had been placed over homologous regions in the left and right hemispheres. They sorted electrode pairs by whether their direct corpus callosum connection had been disconnected or preserved using diffusion tensor imaging and native anatomical MRI, and they estimated functional connectivity between pairs of electrodes over homologous regions using phase-locking value. They found no significant differences in any frequency band between pairs of electrodes that had their corpus callosum connection disconnected and those that had an intact connection. The authors’ results may imply that the corpus callosum is not an obligatory mediator of connectivity between homologous sites in opposite hemispheres.
    [Show full text]
  • Regional Cerebral Perfusion and Amytal Distribution During the Wada Test
    Regional Cerebral Perfusion and Amytal Distribution During the Wada Test Rajith de Silva, Roderick Duncan, James Patterson, Ruth Gillham and Donald Hadley Departments of Neurology, Neuroradiology and Neuropsychology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, Scotland some studies have indicated that cerebral hypoperfusion The distribution of sodium amytal and its effect on regional induced by amytal does not usually involve the mesial cerebral perfusion during the intracarotid amytal (Wada) test temporal cortex (3). What then is the mode of action of the were investigated using high-resolution hexamethyl propyl- test? We have hypothesized that the test works either by eneamine oxime (HMPAO) SPECT coregistered with the pa tient's MRI dataset. Methods: Twenty patients underwent SPECT producing partial inactivation of mesial temporal structures or by inactivating mesial temporal structures indirectly (i.e., after intravenous HMPAO injection, and 5 patients had both intravenous and intracarotid injections in a double injection- by diaschisis). acquisition protocol. Results: All patients had hypoperfusion in To test these hypotheses, it is necessary to have clear and the territories of the anterior and middle cerebral arteries. Basal precise images of perfusion in the mesial temporal cortex. ganglia perfusion was preserved in 20 of 25 patients. Hypoperfu (Jeffery et al. [4] pointed out the difficulty of doing this with sion of the entire mesial temporal cortex was seen in 9 of 25 conventional slicing). It is also necessary to have measures patients. Partial hypoperfusion of the whole mesial cortex or both of the distribution of structures to which amytal is hypoperfusion of part of the mesial cortex was seen in 14 of 25 delivered and of the distribution of structures rendered patients.
    [Show full text]
  • Diagnostic Methods in Traumatic Brain Injury
    Diagnostic Methods in Traumatic Brain Injury Johan Ljungqvist Department of Neurosurgery Institute of Neuroscience and Physiology Sahlgrenska Academy at University of Gothenburg Gothenburg 2017 Cover illustration: Diffusion tensor imaging of the corpus callosum, by Johan Ljungqvist. Diagnostic Methods in Traumatic Brain Injury © Johan Ljungqvist 2017 johan.ljungqvist@gu.se ISBN 978-91-629-0166-0 (PRINT) ISBN 978-91-629-0165-3 (PDF) Printed in Gothenburg, Sweden 2017 INEKO AB To Christina, Astrid and August “Fibres as delicate as those of which the organ of mind is composed are liable to break.” 1 – Gama, 1835 ABSTRACT Background Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Early detection and quantification of TBI is important for acute management, for making early accurate prognoses of outcome, and for evaluating potential therapies. Diffuse axonal injury (DAI) is a distinct manifestation of TBI that often leads to cognitive and neurologic impairment. Conventional neuroimaging is known to underestimate the extent of DAI, and intracranial hematomas can usually be detected only in hospitals with radiology facilities. In this thesis, studies I and II were longitudinal investigations using a magnetic resonance diffusion tensor imaging (MR- DTI) technique to quantify DAI. Study III tested whether a novel blood biomarker, neurofilament light (NFL) could identify DAI. Study IV tested whether a microwave technology (MWT) device, designed for use also in a prehospital setting, could detect intracranial hematomas. Patients and methods In study I, MR-DTI of the corpus callosum (an anatomical region prone to DAI) was performed in eight patients with suspected DAI in the acute phase and at 6 months postinjury.
    [Show full text]
  • Efficacy and Safety of Corpus Callosotomy After Vagal Nerve Stimulation in Patients with Drug-Resistant Epilepsy
    CLINICAL ARTICLE J Neurosurg 128:277–286, 2018 Efficacy and safety of corpus callosotomy after vagal nerve stimulation in patients with drug-resistant epilepsy Jennifer Hong, MD,1 Atman Desai, MD,2 Vijay M. Thadani, MD,3 and David W. Roberts, MD1,3 1Section of Neurosurgery, Department of Surgery, 3Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; and 2Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, California OBJECTIVE Vagal nerve stimulation (VNS) and corpus callosotomy (CC) have both been shown to be of benefit in the treatment of medically refractory epilepsy. Recent case series have reviewed the efficacy of VNS in patients who have undergone CC, with encouraging results. There are few data, however, on the use of CC following VNS therapy. METHODS The records of all patients at the authors’ center who underwent CC following VNS between 1998 and 2015 were reviewed. Patient baseline characteristics, operative details, and postoperative outcomes were analyzed. RESULTS Ten patients met inclusion criteria. The median follow-up was 72 months, with a minimum follow-up of 12 months (range 12–109 months). The mean time between VNS and CC was 53.7 months. The most common reason for CC was progression of seizures after VNS. Seven patients had anterior CC, and 3 patients returned to the operat- ing room for a completion of the procedure. All patients had a decrease in the rate of falls and drop seizures; 7 patients experienced elimination of drop seizures. Nine patients had an Engel Class III outcome, and 1 patient had a Class IV outcome.
    [Show full text]
  • Corpus Callosotomy E21 (1)
    CORPUS CALLOSOTOMY E21 (1) Corpus Callosotomy Last updated: September 9, 2021 HISTORY ......................................................................................................................................................... 1 EXTENT OF PROCEDURE ................................................................................................................................ 1 INDICATIONS .................................................................................................................................................. 2 PREOPERATIVE TESTS .................................................................................................................................... 2 PROCEDURE ................................................................................................................................................... 2 Anesthesia .............................................................................................................................................. 2 Position ................................................................................................................................................... 2 Incision & dissection .............................................................................................................................. 3 Callosotomy ........................................................................................................................................... 3 End of procedure ...................................................................................................................................
    [Show full text]
  • Callosotomía: Técnicas, Resultados Y Complicaciones. Revisión De La Literatura Callosotomy: Techniques, Results and Complications - Literature Review
    Revista Chilena de Neurocirugía 42: 2016 Callosotomía: técnicas, resultados y complicaciones. Revisión de la literatura Callosotomy: techniques, results and complications - Literature Review Paulo Henrique Pires de Aguiar1,3,4,5, Alain Bouthillier2, Iracema Araújo Estevão6, Bruno Camporeze6, Mariany Carolina de Melo Silva6, Ivan Fernandes Filho7, Luciana Rodrigues8, Renata Simm8, José Faucetti9. 1 Division of Neurosurgery, Santa Paula Hospital - São Paulo - SP, Brazil. 2 Division of Neurosurgery, Department of Surgery, University of Montreal - Quebec, Canada. 3 Division of Neurosurgery, Oswaldo Cruz Hospital - São Paulo - SP, Brazil. 4 Division of Post-Graduation, Department of Surgery, Federal University of Rio Grande do Sul - Porto Alegre - RS, Brazil. 5 Professor of Neurology, Department of Neurology, Pontifical Catholic University of São Paulo - Sorocaba - SP, Brazil. 6 Medical School of São Francisco University - Bragança Paulista - SP - Brazil. 7 Medical School of Pontifical Catholic University of São Paulo - Sorocaba - SP, Brazil. 8 Division of Neurology of Santa Paula Hospital - São Paulo - SP, Brazil. 9 Medical artist at the University of São Paulo - São Paulo - SP, Brazil. Rev. Chil. Neurocirugía 42: 94-101, 2016 Abstract Background: Patients with intractable seizures who are not candidates for focal resective surgery are indicated for a pallia- tive surgical procedure, the callosotomy. This procedure is based on the hypothesis that the corpus callosum is an important pathway for interhemispheric spread of epileptic activity and, for drug resistant epilepsy. It presents relatively low permanent morbidity and an efficacy in the control of seizures. Based on literature, the corpus callosotomy improves the quality of life of patients that has the indication to perform this procedure because it allows reducing the frequency of seizures, whether tonic or atonic, tonic-clonic, absence or frontal lobe complex partial seizures.
    [Show full text]
  • Corpus Callosotomy—Open and Endoscopic Surgical Techniques *Matthew D
    EPILEPSY SURGERY TECHNIQUES Corpus callosotomy—Open and endoscopic surgical techniques *Matthew D. Smyth, *Ananth K. Vellimana , †‡Eishi Asano , and §Sandeep Sood Epilepsia, 58(Suppl. 1):73–79, 2017 doi: 10.1111/epi.13681 SUMMARY Corpus callosotomy is a palliative surgical procedure for patients with refractory epi- lepsy. It can be performed through an open approach via a standard craniotomy and the aid of an operating microscope, or alternatively via a mini-craniotomy with endo- scope assistance. The extent of callosal disconnection performed varies according to indications and surgeon preference. In this article, we describe both open and endo- scopic surgical techniques for anterior and complete corpus callosotomy. KEY WORDS: Corpus callosotomy, Callosotomy technique, Complete callosotomy, Endoscopic callosotomy, Epilepsy surgery. Dr. Smyth is a Professor of Neurosurgery at Washington University and St. Louis Children’s Hospital. Corpus callosotomy was introduced by Van Wagenen surgery.2,3,6 Although corpus callosotomy is generally well and Herren in 1940.1 Over time, numerous refinements in tolerated, transient or permanent postoperative neurologic surgical technique have occurred and corpus callosotomy is deficits including hemiparesis, aphasia, mutism, akinesia, now a widely accepted surgical option in appropriately and disconnection syndromes may occur.2,3,6 selected patients. Surgical disconnection of the corpus cal- The extent of callosotomy performed varies across sur- losum disrupts synchronization of epileptiform discharges gical centers, and many surgeons prefer an anterior half or between bilateral cerebral hemispheres and is therefore two thirds callosotomy sparing the splenium, as this has a effective in reducing the severity and frequency of general- lower incidence of postoperative complications.
    [Show full text]
  • Non-Invasive Alternatives to the Wada Test in the Presurgical Evaluation of Language and Memory Functions in Epilepsy Patients
    Special article Epileptic Disord 2007; 9 (2): 111-26 Non-invasive alternatives to the Wada test in the presurgical evaluation of language and memory functions in epilepsy patients Isabelle Pelletier1,2, Hannelore C. Sauerwein1,2, Franco Lepore1,2, Dave Saint-Amour1,3, Maryse Lassonde1,2 1 Centre de recherche du Centre Hospitalier Universitaire Mère-Enfant (Sainte-Justine) 2 Centre de Recherche en Neuropsychologie et Cognition, Département de psychologie 3 Département d’ophtalmologie, Université de Montréal, Canada Received December 4, 2006; Accepted March 26, 2007 ABSTRACT – The cognitive outcome of the surgical removal of an epileptic focus depends on the assessment of the localisation and functional capacity of language and memory areas which need to be spared by the neurosurgeon. Traditionally, presurgical evaluation of epileptic patients has been achieved by means of the intracarotid amobarbital test assisted by neuropsychological measures. However, the advent of neuroimaging techniques has provided new ways of assessing these functions by means of non-invasive or minimally invasive methods, such as anatomical and functional magnetic resonance imaging, positron emission tomography, single-photon emission computed tomography, transcranial magnetic stimulation, functional transcranial Doppler monitoring, magnetoencephalography and near infrared spectroscopy. This paper aims at comparing and evaluating the traditional and recent preoperative approaches from a neuropsychological perspective. Key words: epilepsy surgery, neuroimaging technique, intracarotid amobarbital test, language, memory Surgery to remove epileptic brain tis- providing complete seizure control sue (i.e., lobectomy, lesionectomy, and improved quality of life. The out- hemispherectomy) is a widely used come of the surgery depends on accu- and effective treatment for patients rate localization and lateralization of Correspondence: suffering from intractable seizures the epileptogenic zone as well as on Maryse Lassonde (Gates and Dunn 1999).
    [Show full text]
  • Endoscopic Epilepsy Surgery: Emergence of a New Procedure
    [Downloaded free from http://www.neurologyindia.com on Monday, April 04, 2016, IP: 14.139.245.2] NI Feature: CENTS (Concepts, Ergonomics, Nuances, Therbligs, Shortcomings) ORIGINAL ARTICLE Endoscopic epilepsy surgery: Emergence of a new procedure Sarat P. Chandra, Manjari Tripathi1 Departments of Neurosurgery and 1Neurology, All India Institute of Medical Sciences, New Delhi, India ABSTRACT Background: The use of minimally invasive endoscopic surgery is fast emerging in many subspecialties of neurosurgery as an effective alternative to the open procedures. Objective: The author describe a novel technique of using an endoscope for performing a corpus callosotomy and hemispherotomy. A description of endoscopic disconnection for a hypothalamic hamartoma (HH) and a review of the literature is also presented. Materials and Methods: Thirty four patients underwent endoscopic procedures between January 2010 and March 2015. These included endoscopic‑assisted inter‑hemispheric trans‑callosal hemispherotomy (EH; n = 11), endoscopic‑assisted corpus callosotomy with anterior/posterior commissurotomy (CCWC; n = 16), and endoscopic disconnection for HH (n = 7). EH and CCWC were performed with the use of a small craniotomy (4 cm × 3 cm). The surgeries were performed using a rigid high‑definition endoscope, bayonetted self‑irrigating bipolar forceps, and other standard endoscopic instruments along with the guidance of intra‑operative magnetic resonance imaging and neuronavigation. HH disconnection was performed using endoscopic neuronavigation through a burr hole. Results: Hemispherotomy: Sequelae of middle cerebral artery infarct (5), Rasmussen’s syndrome (3), and hemimegalencephaly (3). Outcome: Class I Engel (9) and class II (2), mean follow‑up of 8.4 months, range: 3–18 months. Mean blood loss: 85 cc, mean operating time: 210 min.
    [Show full text]
  • Magnetoencephalography (MEG)
    Model Coverage Policy Magnetoencephalography (MEG) INTRODUCTION Magnetoencephalography (MEG), also known as seizures.1 Early resective epilepsy surgery has beneficial Magnetic Source Imaging (MSI) is the noninvasive effects on progressive and disabling consequences of measurement of the magnetic fields generated by brain uncontrolled seizures. Timely recognition and referral are vital activity. Typical MEG recordings are made within a to realization of the benefits of epilepsy resective surgery.2,3 magnetically shielded room using a device that has 100 Value of MEG in localization and resective surgery. to 300 magnetometers or gradiometers (sensors). They A cardinal principle in resective surgery is to remove only are arranged in a helmet-shaped container called a Dewar. the abnormal tissue and preserve normal functional tissue. The Dewar is filled with liquid helium needed to produce This is particularly crucial in the cortical regions of the brain. superconductivity. The brain sources producing the magnetic Normal and abnormal tissues are often in close proximity and field maps can be easily mapped and displayed on a co- may appear contiguous and indistinguishable to naked eye registered MRI. This results in a visual display of normal inspection. brain activity such as the location of eloquent cortex for vision, touch, movement, or language. It displays equally well Even when the abnormal structure, such as a vascular abnormal brain activity such as epileptic discharges. Such malformation, may be obvious, the location of a normal depictions are useful in pre-surgical brain mapping in patients eloquent brain tissue cannot be determined without with epilepsy, brain tumors, and vascular malformations. specialized testing. Eloquent areas are those subserving essential functions such as the sense of touch, vision Importance of epilepsy surgery.
    [Show full text]