APPENDIX Cranial : and Physiology

We have 12 ; some are sensory nerves, some are motor nerves, and some are part of the autonomic .

I. Olfactory Sensory: Smell II. Optic Sensory: Vision III. Oculomotor Motor: Eye Movements: Innervates all , except the superior oblique and lateral rectus mus- cles. Innervates the striated muscle of the eyelid. Autonomic: Mediates pupillary constriction and accommodation for near vision. IV. Trochlear Motor: Eye Movements: Innervates . V. Trigeminal Sensory: Mediates cutaneous and proprioceptive sensations from skin, muscles, and joints in the face and mouth, includ- ing the teeth and the anterior two-thirds of the tongue. Motor: Innervates muscles of mastication. VI. Abducens Motor: Eye Movements: Innervates . VII. Facial Motor: Innervates muscles of facial expression. Autonomic: Lacrimal and salivary glands. Sensory: Mediates and possible sensation from part of the face (behind the ear). Nervous intermedius: around the ear; possibly taste. VIII. Vestibulocochlear Sensory: Equilibrium, postural , orientation of the head in space. IX. Glossopharyngeal Sensory: Taste Innervates taste buds in the posterior third of tongue. Sensory: Mediates visceral sensation from palate and posterior third of the tongue. Innervates the carotid body. Motor: Muscles in posterior throat (stylopharyngeal muscle). Autonomic: . X. Vagus Sensory: Mediates visceral sensation from the , , , and . Innervates the skin in the ear canal and taste buds in the epiglottis. Autonomic: Contains autonomic fibers that innervate smooth mus- cle in heart, blood vessels, trachea, bronchi, esopha- gus, stomach, and intestine. Motor: Innervates striated muscles in the soft palate, pharynx, and the larynx. XI. Spinal accessory Motor: Innervates the and sternocleidomastoid muscles. XII. Hypoglossal Motor: Innervates intrinsic muscles of the tongue.

343 344 Intraoperative Neurophysiological Monitoring

CN VI. Abducens : Controls eye FUNCTIONS OF THE CRANIAL movements from the midline toward the side. NERVES Lesion to CN VI prevents movements of the eye from the midline and outward. CN I. : Communicates chemical airborne messages to the . CN VII. : Controls the face. CN II. : Communicates optic CN VII is often monitored intraoperatively information. Variations in contrast are the most because it is at risk in all operations to powerful stimulations of the . remove acoustic tumors and it is involved in diseases such as hemifacial spasm. The auto- CN III. : Controls all of nomic fibers of CN VII control both tear the extraocular eye muscles, except the glands and salivary glands. A loss of facial trochlearis and the lateral rectus muscles; thus, function is cosmetically important and makes it innervates the superior, the inferior, the it difficult to eat, and the lack of tears and the medial rectus, and the inferior oblique muscles. inability to close the eye might result in This muscle moves the eye in all directions; injures to the cornea. therefore lesions to CN III affect essentially all Nervus intermedius: Perhaps taste. Deep eye movements and cause the eye to be devi- (geniculate ). ated downward and outward. It also innervates the eyelid and makes it possible to close the eye CN VIII. : The when lying down. Lesions to CN III cause pto- two parts of this nerve communicate auditory sis (partial closure of the eyelid). CN III con- information and information about head move- tains autonomic fibers that control the size of ments. Whereas the covering of the nerve fibers the pupil and stretches the lens to achieve of most of the cranial nerves changes accommodation. Lesions to the CN III essen- from peripheral to central myelin a few tially make the eye useless. millimeters from the brainstem, the transitional zone for CN VIII is in the internal auditory CN IV. Trochlearis nerve: Controls the meatus, which means that CN VIII throughout trochlear muscle, and contraction of this mus- its entire intracranial course is covered with cle causes the eye to move downward when it central myelin and it has no epineurium. This is in a position medial to the midline. Lesions means that CN VIII has mechanical properties of CN IV affect downward and inward move- similar to those of the brain, making it more ments of the eye. fragile than other cranial nerves. The vestibular portion of CN VIII communi- CN V. : This nerve’s sen- cates to the brain information gathered by the sory portion — the portio major — innervates the about the position of the head. In fact, skin of the face and the cornea. This portion of we can do quite well without the vestibular por- CN V thereby communicates sensory informa- tion of CN VIII, but if it is injured on one side tion about touch and pain from the face and the only, severe balance disturbances can result; mouth. CN V is the nerve that causes toothache however, one can adapt to such dysequilibrium and the severe pain of . depending on one’s age (better when younger Lesions to the sensory portion of CN V cause a than when older). loss of sensation of the face. Loss of corneal sen- sation could result in corneal bruises. CN IX. Glossopharyngeal nerve: Com- The motor potion of CN V –– the portio municates sensory information from the throat minor –– controls the muscles of mastication. to the brain and information about blood pres- Lesions to the motor portion of CN V cause sure to the cardiovascular centers. The motor atrophy of the mastication muscles. portion of CN IX controls the stylopharyngeal Appendix Cranial Nerves: Anatomy and Physiology 345 muscle. Lesions of CN IX will cause a loss of effect on the cardiovascular system, but the effect gag on the affected side and a risk of of bilateral severance of the vagal nerve is severe. choking on food. Lesions on one side will likely The might carry more complex sen- have little effect on cardiovascular function, but sory information from the lower body. a loss of CN IX on both sides is fatal. CN XI. Spinal : Controls CN X. Vagus nerve: This nerve’s name muscles in the and shoulder (sternocleido- means the “vagabondering” nerve, descriptive in mastoid and trapezoid muscles). Lesions of CN that it travels around in a large portion of the XI cause atrophy of the muscles that are inner- body. This nerve conveys parasympathetic input vated by that nerve. to the entire chest and abdomen. The vagus nerve also controls the vocal cords, the heart, and the CN XII. : Controls diaphragm. The most noticeable effect of unilat- movements of the tongue. Unilateral lesions to eral lesions to CN X is hoarseness, because the CN XII cause deviation of the tongue and atro- vocal cord on the affected side cannot close. phy of the tongue on the affected side. Bilateral Although CN X carries information to and from lesions make it almost impossible to speak and the heart, unilateral lesions to CN X have little is impaired. Abbreviations

μS: Microseconds ICC: Central of the inferior AAF: Anterior auditory field colliculus ABI: Auditory brainstem implants IPL: Interpeak latency ABR: Auditory brainstem response ISI: Inter stimulus interval AI: Primary auditory cortex kHz: Kilohertz AICA: Anterior inferior cerebellar artery kOhm: Kiloohm AII: Secondary cortex LED: Light-emitting diodes AP: Action potentials LGN: Lateral geniculate nucleus AVCN: Anterior ventral LL: CAP: Compound action potentials mA: Milliampere CCT: Central conduction time ma: Milliampere cm: Centimeter MAC: Minimal end-alveolar concentration CM: Cochlear microphonics MCA: Middle cerebral artery CMAP: Compound muscle action potential MEP: Motor evoked potentials CMN: Centromedian nucleus MGB: Medial geniculate body CN I-XII: Cranial nerves I-XII MGP: Medial segment of globus pallidus CN: Cochlear nucleus MI: Primary CNAP: Compound nerve action potentials mm: Millimeter CNS: MOhm: Megaohm CPA: ms: Millisecond CPG: Central pattern generator MSO: Medial superior olivary nucleus CSF: mv: Millivolts CT: Corticospinal tract MVD: Microvascular decompression DAS: Dorsal acoustic stria (operations) dB: Decibel NF2: type 2 DBS: Deep brain stimulation NIHL: Noise induced hearing loss DC: Direct electric current NMEP: Neurogenic motor evoked potentials DCN: Dorsal cochlear nucleus NTB: Nucleus of the trapezoidal body DPV: Disabling positional PAF: Posterior auditory field DRG: Dorsal root ganglia PD: Parkinson’s disease ECoG: Electrocochleographic PeSPL: Peak equivalent sound pressure level EEG: Electroencephalographic PICA: Posterior inferior cerebellar artery (potentials) PMC: Premotor cortical (areas) EKG: Electrocardiogram (or pps: Pulses per second electrocardiographic) PVCN: Posterior ventral cochlear nucleus EMG: Electromyographic (potentials) REZ: Root exit zone (or root entry zone) EPSP: Excitatory postsynaptic potential RMS: Root mean square GPe: Globus pallidus external part SI: Primary somatosensory cortex CPG: Central pattern generator SMA: Supplementary motor area GPi: Globus pallidus internal part SNc: Substantia nigra pars compacta GPN: Glosso-pharyngeal neuralgia SNR: Signal-to-noise ratio HD: Huntington’s disease SNr: Substantia nigra is the pars reticulata HFS: Hemifacial spasm SOC: Superior olivary complex HL: Hearing level SP: Summating potential Hz: Hertz, cycles per second SSEP: Somatosensory evoked potentials

347 348 Intraoperative Neurophysiological Monitoring

STN: Subthalamic nucleus V: Volts TC-MEPs: Transcranial motor evoked VAS: Ventral acoustic stria potentials VEP: Visual evoked potentials TES: Transcranial electrical stimulation Vim: Intermediary nucleus of the thalamus TGN: Trigeminal neuralgia μS: Microsecond TIVA: Total intravenous anesthesia μV: Microvolt TN: Trigeminal neuralgia μA: Microamps Index 349

Index

A (CN VI), 177, 207, 343 muscle relaxants, 281 Abnormal muscle response, 256 total intravenous (TIVA), 280 Acoustic tumor operations, see vestibular Anteriorlateral (somatosensory) system, 72 schwannoma Artifacts, stimulus, Action potentials, nerve fibers, 22, 230, 268 nature, 301, 303, 312, 315, 328 Aliasing, how to avoid, 315 reducing, 304, 307, 320, 327, 328 Alpha motoneurons, 157,168, 185, 187, 193 Ascending auditory pathways, Amplifiers, classical, 61 common mode rejection, 301 electrical potentials, 65 filters, 302 non-classical, 62 maximal output, 301 Ascending somatosensory pathways, Anatomy, anteriorlateral system, 72 auditory pathways, 61 dorsal column system, 70 basal ganglia, 155, 158, 159 Ascending visual pathways, 82 , 162 Audio amplifiers and loudspeakers, 308 cerebral cortex, 62, 65, 71, 81, 82, 157, Auditory brainstem implants (ABI), 160, 173 monitoring placement of ear, 55 electrodes, 267 motor pathways, 157 Auditory brainstem responses (ABR), , 70 as indicator of brainstem manipulations, 118 , 70, 157, 164, 167 display, 93 visual pathways, 82 electrode placement, 90 Anatomical location of nerve injuries, farfield potentials (ABR), 86 assessment, 230 interpretation, 105 Anesthesia requirements, monitoring, 85 ABR, 124 neural generators, 68 cortical evoked somatosensory optimal filtering, 300 potentials, 142 optimal stimulation, 87 guidance for implantation of electrodes processing, 67, 303, 308, 313 for deep brain stimulation, 271 stimulus artifact, 301, 303 identification of central sulcus, 249 wave form, 66 monitoring motor systems, 189, 279 Auditory evoked potentials (near field), monitoring sensory systems, 279 interpretation, 105 recording of EMG, 191 recording from auditory nerve, 93 recording of EMG potentials, 282 recording from cochlear nucleus, 94 visual evoked potentials, 147 Auditory nerve, Anesthesia, as generator of peak I and II of ABR, 69 basic principles, 279 conduction block, 106 effect on neuroelectric potentials, 281 conduction velocity, 69 inhalation, 279 recording compound action potentials intravenous, 280 from, 93, 103

349 350 Index

Auditory prostheses, placement of cochlear Communication, nucleus stimulating electrodes, 267 importance, 287 , anatomy and physiology, 55 in the operating room, 48 Axonotmesis, 224 Compound action potentials, auditory nerve, 103 B long nerve, 25 Basal ganglia, peripheral nerves, 226, 230, 256 guide of electrode placement for deep Compound muscle action potentials brain stimulation, 264 (CMAPs), 31, 191 organization, 159 Computer systems, 308 Bipolar, Conduction block, peripheral nerve, 37, 225 recording from a nerve, 28, 309, 328, 328 Conduction velocity, vs monopolar recording in localizing mixed nerves, 27, 221 nerves, 239, 309 peripheral nerves, 222 stimulation, 202, 209, 309 sign of injury, 226 Blood supply, Constant voltage or constant current , 140 stimulators, to spinal cord, 126, 169 monitoring extraocular muscles, 208 Brainstem manipulations, ABR as indicator, 118 monitoring facial nerve, 202, 239 pedicle screw monitoring, 188 C Corticospinal system, CAP, see compound action potentials anatomical organization, 164 Cause of injury to the auditory nerve, interpretation of recorded responses, 184 heating, 106 monitoring, 172,179, 181, 183 stretching, 106 recording from (D and I waves), 172, unknown, 116 181, 183 Central conduction time (CCT), 78, 139, Cotton wick electrode, 93, 94 141, 144 Cranial motor nerves, Central control of muscle tone and anatomical organization, 177, 343 excitability, 176 localizing, 237 Central sulcus, identification, 247 monitoring, 197, 237 Cerebellum, 162 Cranial nerves, Cerebral perfusion, anatomy and physiology, 343 compared with measurement of blood Cunate nucleus, 71 flow, 141 Cut end response, 37 SSEP as indicator, 139 Choice of operations to be monitored, 335 D , D and I waves, 172, 181, 183 anatomy, 55 Data analysis, 309 electrical potentials, 60 Dermatomes, implants, 267 monitoring of SSEP, 127, 131 , see auditory nerve organization, 128 Cochlear nucleus, Descending pathways, anatomy, 61, 69 auditory, 65 implants (ABIs), 267 motor, 164 placement of stimulating electrodes, 267 Diagnosis of injury to peripheral nerves, 251 recording, 94, 103 Differential amplifiers, see Amplifiers Index 351

Digital filters, for evoked potentials, 97, cost benefit analysis, 333 101, 320 promotion of better operating methods, Display units, 308 335 Dorsal column nuclei, 71 reduction of postoperative deficits, 331 Dorsal column system, anatomy, 71 research in the operating room, 337 Dorsal horn of the spinal cord, anatomy, shorten operating time, 335 166 Evaluation of postoperative deficits, 333 Dorsal root, , 242 Extraocular muscles, monitoring, 207

E F Ear, Facial muscles, anatomy, 55 recording EMG, 199, 238, 240, 257 physiology, 57 other indications of contractions, 199 Earphones, 41, 307 Facial nerve, location of injury of ECoG, see electrocochleographic potentials intracranial portion, 204 Efficacy of monitoring, 336 Facial nerve monitoring, Electrical interference, extracranial portion, 206 different kinds, 47 intracranial portion, 197 how to reach monitoring equipment, 291 False negative responses, 329, 336 how to reduce effects, 292 False positive responses, 329, 336 identification of source, 286, 287 Far field potentials, see also ABR, SSEP, Electrical safety, 294 and VEP, Electrical stimulators, characteristics, 34 constant current, 188, 304 display of results, 46 constant voltage, 202, 208, 304 optimal recording, 45 maximal output, 305 recording, 45 Electrocoagulation (electrocautery), selection of stimulus and recording interference, 294, 312 parameters, 46, 299, 308 hazards, 294 Filtering, Electrocochleographic (ECoG) potentials, analog (electronic) filters, 92, 319 recording, 104 digital filters, 92, 320 Electromyographic potentials (EMG), electronic low- and high-pass, in extraocular muscles, 207 amplifiers, 302 facial muscles, 199 Filters, recording, 282, 283 band-pass, 302, 320 skeletal muscles, 183, 186, 188 Bessel filters, 303 Erb’s point, 128 digital, 92, 320 Evoked potentials, weighting function, 322 auditory, 85 zero-phase finite impulse response, recording, 281, 283, 285, 292, 294 320 somatosensory, 125, 280 Wiener filters, 325 visual, 145 electronic, 92, 302, 319 Extraocular muscles, high-pass, 302 anatomy, 177, 207 “intelligent” filters, 325 recording EMG potentials, 207 low-pass, 301, 302 Evaluating benefits of intraoperative notch, 303 monitoring, Floor of fourth ventricle, mapping, 245 352 Index

G I–J Generators, neural, Injured peripheral nerves, diagnosis, 251 ABR, 68 Interference, SSEP, 77 blood warmer, 290 Glossopharyngeal nerve (CN IX), 178, 343 electrical, 287 Gracile nucleus, 71 from power line, 286 Grounding (equipment), 288, 293, 296 how to reduce effects, 291 Guiding the surgeon in operations, identification of source, 288 basal ganglia for deep brain stimulation, infusion pumps, 290 265 periodic, 287 diagnosis of injured nerves, 251 signature, 289 finding central sulcus, 247 spectrum, 289 finding safe entry to brainstem, 245 Interference, magnetic, identification of specific , 237 how to reduce effects, 292 localizing motor nerves, 237 identification of source, 289 making lesions in the brain, 264 Interpretation of changes in sensory evoked mapping, potentials, auditory-, 241 auditory evoked potentials, 105, floor of the fourth ventricle, 245 relationship with hearing acuity, 113 the spinal cord, 244 Intraoperative, peripheral motor nerves, 240 diagnosis of nerve injuries, 229 sensory nerves, 240 measurement of nerve conduction, 229 spinal cord, 245 , SSEP as indicator, 139 spinal dorsal roots, 242 Jendrassik maneuver, 176 trigeminal , 241 microvascular decompression (MVD) for L–M hemifacial spasm, 256 Lateral spinal tracts, anatomical neuroma in continuity, 251 organization, 164, 166 placement of ABIs electrodes, Lateral spread response, see abnormal 267, 269 muscle response, 257 Light stimulators, 42, 307 H Localizing cranial motor nerves, 237 Hazard, electrical, see electrical hazard Localizing site of injury, 252 Hearing loss, motor nerves 237, 240 auditory nerve, 115 peripheral nerves, 230 cochlear, 66, 87, 115 Loudspeakers and audio amplifiers, 308 conductive, 66, 87, 114 Low-pass filters, see filters, low-pass Heat as a cause of injury, MAC, see Minimum alveolar concentration auditory nerve, 99, 105, 107 Magnetic interference, facial nerve, 203 identification of source, 287, 289 Hemifacial spasm (MVD operations), how reach recording equipment, 292 abnormal muscle response, see abnormal how to reduce effects, 292 muscle response Magnetic stimulation of nervous tissue, 43, identification of compressing vessel, 179, 182 256 Magnetic stimulators, 306 monitoring of auditory nerve, 264 Mapping central structures, monitoring of facial nerve, 205 central sulcus, 247 Index 353

floor of the fourth ventricle, 245 Muscle relaxants (paralysis), peripheral motor nerves, 240 component of anesthesia, 281 sensory nerves, 240 monitoring of facial nerve, 258 spinal cord, 244, 245 monitoring of spinal motor system, 184, Mapping nerves, 185, 190, 193 auditory-vestibular nerve, 241 recording of abnormal muscle response, branches of the trigeminal nerve, 241 258, 271 central motor nerves, 237 testing, 291 peripheral motor nerves, 240 MVD, see Microvascular decompression sensory nerves, 240 operations spinal dorsal roots, 243 N Masking of auditory evoked potentials by drilling, 116 Near field potentials, general, 23, 24 Mechanically induced facial nerve activity, Near field potentials, recorded from, in operations for vestibular cerebral cortex, 45, 247 schwannoma, 202 cord, 181, 182, 183, 187 Medial spinal tracts, fiber tracts, 44 anatomical organization, 164, 167 muscles (EMG), 43, 183, 185, 187, 190, Median nerve, stimulation, 125, 127 199, 201, 252, 257, 263 nuclei, 45, 94 Microelectrodes, peripheral nerves, 11, 27, 45, 230, 252 equipment for recording with, 266 Nerves, properties, 265 conduction velocity, 11, 23, 27, 37, 44, use in recording unit potentials, 265 69, 221, 229 use in recordings from basal ganglia, 265 cranial, 85, 93, 197, 343 Microvascular decompression (MVD) long, 27 operations, identification of peripheral, 229, compressing vessel in hemifacial signs of injury, 37, 224, 226, 230 spasm, 256 Neural generators, Middle ear, 55 ABR, 66, 68 Minimum alveolar concentration (MAC), SSEP, 77, 79 279 VEP, 84 Mistakes, how to reduce, 284 Neurapraxia, 224 Monopolar recording, Neurogenic evoked potentials from spinal auditory nerve, 93, 103,105 cord, 139 cochlear nucleus, 94 Neuroma in continuity, 251 from a long nerve, 25, 230 Non-classical sensory pathways, 61, 62, 73, 82 Motor cortex, Nonspecific descending motor system, 167 direct electrical stimulation, 172, 182 Non-surgical factors, localization, 247 irrigation, 114, 116 transcranial electrical stimulation (TES), temperature, 127 24, 172, 180, 212 Notch filters, 303 transcranial magnetic stimulation (TMS), Nucleus Z, 71 172, 182 Nyquist frequency, 315 Motor evoked potentials (MEP), recording, 180, 185 O–P Motor pathways, anatomy and physiology, 157 Obersteiner-Redlich zone, 112 Multiunit recordings, 265 Oculomotor nerve (CN III), 177, 207, 209, 343 354 Index

Optic nerve (CN II), 82, 145, 343 Recording techniques, , 82, 145, 343 bipolar and monopolar recordings, 309 Otoacoustic emission, 60 far field evoked potentials, 309 Output limitations, Reliability of monitoring, 48 amplifiers, 301 stimulators, 306 S Parkinson’s disease, 161 Safety, electrical, Pathology of peripheral nerves, operating room personnel, 297 classification, 224 patients, 295 diagnosis, 251 Scoliosis operations, monitoring, 188 Pedicle screw, Segmental pathways, spinal cord, 167 cost-benefit analysis, 334 Sensory systems, anatomy and physiology, monitoring, 132,188 55 Periodic interference, see interference Signal processing, Peripheral nerves, artifact rejection, 311 anatomy and physiology, 221 optimizing signal averaging, 312 classification, 221 reducing effect of amplifier blockage, conduction velocity, 222 312 diagnosis of injury, 251 signal averaging, 310 localizing site of injury, 252 Signature of interference, 289 measurements of conduction, 229 base operations, monitoring, neuroma in continuity, 251 ABR as indicator of brainstem pathology, 225 manipulations, 85, 118 regeneration of injured nerves, 226 extraocular muscles, 206 response to electrical stimulation, 24 facial nerve, 198, 205 responses to natural stimulation, 24 lower cranial nerves, 211 stimulus and recording parameters, 254 motor portion of CN V, 206 Post-operative deficits, estimation, 329, Slowly varying evoked potentials, signal 331, 332 averaging, 313 Power line interference, see interference, Somatosensory cortex, electrical and magnetic anatomical organization, 71 Excitatory postsynaptic potential (EPSP), 24 recording, 247 Pre-and postoperative tests, Somatosensory evoked potentials (SSEP), ABR, 40, 86 interpretation of responses, 136 facial function, 332 lower limb, 127, 128, 134,142 hearing threshold and speech indicators of cerebral ischemia, 125, 137, discrimination, 40, 86, 114, 332 139 SSEP, 40, 136, monitoring of peripheral nerves, 131 Preparing the patient for monitoring, 41 monitoring of spinal cord, 125, neural generator, Q–R upper limb SSEP, 79 Quality control, lower limb SSEP, 78 evoked potentials, 308, 313 recording from spinal cord, 137 microelectrode recordings, 267 recording of short latency potentials, Recording and stimulating electrodes, 41 127 Rejection filters, see notch filters stimulation, 127, 132 Rolandic fissure, see central sulcus upper limb, 75,125, 127, 133, 136, 142 Index 355

Somatosensory system, output limitations, 306 ascending pathways, anatomy, light, 307 dorsal column system, 70 magnetic, 304, 306 anterior lateral system, 72 sound (earphones), 307 electrical potentials from, see Stimulus artifacts, reduction, somatosensory evoked potentials auditory evoked potentials, 301, 303 receptors, 70 computer programs, 327 Sound generators, 307 electrical stimulation, 304 Spinal cord monitoring, magnetic stimulation, 184 motor system, 179 overloading amplifiers, 183 SSEP, 125, 188 Stimulus-dependent latency, 24 Spinal cord monitoring, motor evoked Sunderland, grades of neural injury, 224 potentials (MEP), Suppression of evoked potentials, electrical stimulation of exposed cerebral from anesthesia, 141, 142 cortex, 183 Suppression of motor responses, electrical stimulation of spinal cord, 180 from anesthesia, 192 recording from spinal cord, 183 from lack of attention, 177 recording, 180, 184 stimulation of spinal cord, 187 T transcranial electrical stimulation (TES), Temporal dispersion of action potentials, 24, 172, 180, 212 effects, 26 transcranial magnetic stimulation (TMS), Ten-twenty system, 129 172, 182 Thalamus, in motor systems, 162 Spinal cord tumor operations, 188 Total intravenous anesthesia (TIVA), 280 Spinal motor pathways, organization, Transcranial electrical stimulation (TES), corticospinal tract, 164 24, 172, 180, 212 reticulospinal tract, 164 Transcranial magnetic stimulation (TMS), rubrospinal tract, 164 172, 182 tectospinal tract, 164 Trigeminal nerve (CN V), vestibulospinal tract, 164 anatomy, 73, 343 Spinal medial system, see medial spinal mapping trigeminal nerve root, 241 tracts monitoring motor portion, 207 Spinal lateral system, see lateral spinal Trigeminal evoked potentials, 142 tracts Trigeminal system, anatomical Spinal reflexes, 168 organization, 73 Spinal roots, stimulation, 189 (CN IV), 177, 207, 343 Stimulating electrodes, 41, 199, 202, 209, 211, 238, 242, 247, 249, 253, 256, 307 U–Z Stimulation, electrical, Unit responses, bipolar, 202, 256, 309 basal ganglia and thalamus, 265 monopolar, 201, 309 nerve fibers, 22 tripolar, 253, 256 Upper limb SSEP, see somatosensory Stimulation of spinal roots, 189 evoked potentials Stimulators, Vestibular Schwannoma operations, electrical, 303 monitoring, constant current and constant ABR, 101, 209 voltage, 304 brainstem manipulations, 118 356 Index

CAP from auditory nerve, 93 Visual system, CAP from cochlear nucleus, 94 ascending visual pathways, 82 electrocochleographic (ECoG) cortex (striate), 82 potentials, 104 evoked potentials, 83 facial nerve, 198 eye, 82 Visual evoked potentials, Weighting function, see digital filters indicator of optic nerve injury, 145 Wick electrode, 93, 94 monitoring, 145, Wiener filtering, see digital filters neural generators, 84 Zero phase digital filters, see digital filters