Society Proceedings

Abstracts of the 42nd Annual Meeting of Japanese Society of ClinicalNeurophysiology, Shinjyuku, November 8–10, 2012

Yoichi Katayama a, Koichi Hirata b,⇑a Nihon University School of Medicine, Tokyo, Japan,b Dokkyo Medical University, Tochigi, Japan

Symposium

S1-1. Spinal cord stimulation for post-stroke pain—Toshiki Obu-chi, Mitsuru Watanabe, Koichiro Sumi, Toshikazu Kano, KazutakaKobayashi, Hideki Oshima, Chikashi Fukaya, Atsuo Yoshino,Takamitsu Yamamoto, Yoichi Katayama (Nihon University Schoolof Medicine, Tokyo, Japan)

Spinal cord stimulation (SCS) is used to treat for several types ofintractable pain syndromes, but it is not commonly used for treatingpost-stroke pain. Therefore, in this study, we analyzed the effects ofSCS in patients with post-stroke pain. Neurological imaging andpharmacological analysis using thiopental, ketamine and morphinetests were conducted for 30 patients with post-stroke pain. For allpatients, percutaneous electrodes were inserted under local anesthe-sia, and trial stimulation was performed for 5–7 days. If the patientexperienced pain relief during the trial stimulation, a pulse generatorwas implanted. Of the 30 patients, 26 (87%) experienced satisfactorypain relief and underwent implantation. Ten patients received dual-octad lead SCS. The stimulation induced adequate paresthesia in all10 patients. Nine (90%) of the 10 patients experienced satisfactorypain relief and opted for pulse generator implantation in order toproceed with the treatment. Upper cervical SCS was performed forpatients with pain in not only the upper and lower extremities butalso the face. Upper cervical SCS provided good paresthesia coverageand was effective for such patients. We think that patients withpost-stroke pain may respond favorably to dual-octad lead SCS,and advancements in devices for SCS would further improve treat-ment outcomes for such patients.

doi:10.1016/j.clinph.2013.02.027

S1-3. Spinal cord stimulation in Parkinson disease—TadashiIchikawa (Saitama Prefectural Rehabilitation Center, Ageo, Japan)

The new devices introduced for spinal cord stimulation (SCS)enable us to choose stimulation contacts and to change the stimu-

lation conditions even after implantation. SCS is used for treatingchronic pain that is resistant to medication. Many patients withParkinson disease (PD) develop pain as a non-motor manifestation.SCS lead to gait improvement in our 5 patients with PD-relatedpain. The mechanism underlying the SCS-induced improvement inParkinsonian gait is not known. Gait is thought to be controlledby mainly 3 regions, the midbrain locomotion region, brain stemlocomotion region, which is the pedunculopontine nucleus inhumans, and spinal central pattern generator (CPG). Dimitrijevicet al. showed locomotion-like reciprocal electromyogram burstsfor the lower legs of patients with complete spinal cord injury; thissuggests that the CPG is important for gait improvement (Ann N YAcad Sci. 1998 Nov). Epidural SCS-induced locomotion in mouseand rat models of PD; the induction of locomotion was more pro-nounced when l-dopa was administered along with SCS, indicatingthat the central mechanisms play a role in locomotion induction(Fuentes et al., Science 20 March 2009). Further studies arerequired to elucidate the mechanism of SCS-induced gait improve-ment in patients with PD.

doi:10.1016/j.clinph.2013.02.028

S1-4. The effect of repetitive Transcranial Magnetic Stimulation(rTMS) in patients with intractable cervical dystonia and/or post-stroke central pain—Norihiro Muraoka a,b, Minoru Shigemori a,Fumihiko Koike a, Masao Hiromatu a, Keiko Suematu b, MotohiroMorioka b (a Yanagawa Rehabilitation Hospital, Yanagawa, Japan,b Kurume University School of Medicine, Kurume, Japan)

Non-invasive rTMS has been recently used in the evaluation ofvarious neurological disorders. The aim of this study is to clarifythe therapeutic effects of rTMS in patients with intractable cervicaldystonia (CD) and/or central post-stroke pain (CPSP).

In 6 patients with CD, low-frequency rTMS (0.2 Hz) was appliedto the frontal area (including pre-motor cortex), 100 times per ses-sion once a week for 6 months. Only single session reduced themuscle pain for 4–7 days. Reduction of Pain Scale and SeverityScale of Toronto Western Spasmodic Torticollis Rating Scale wasobserved among 2 months’ session. Not only abnormal posturesbut also repetitive movements were reduced among 6 months’session.

doi:10.1016/j.clinph.2013.02.025

⇑ Address: Department of Neurology, Dokkyo Medical University, 880 Kitakobay-ashi, Mibu, Shimotsuga, Tochigi 321-0293, Japan. Tel.: +81 282 87 2152; fax: +81 28286 5884.

E-mail address: hirata@dokkyomed.ac.jp (K. Hirata).

Clinical Neurophysiology 124 (2013) e19–e38

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Clinical Neurophysiology

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c l i n p h

In 8 patients with CPSP, high-frequency rTMS (10 Hz) was appliedto the primary motor cortex, 500 times per session among every3 days. The pain was dramatically reduced by single session alone.But, the effect on spontaneous pain is limited in all sessions. Theimprovement on affective component of the McGill Pain Question-naire (MPQ) was better than the other component of MPQ in allsessions.

In conclusion, rTMS is useful as one of the option in the treatmentof intractable CD and CPSP.

doi:10.1016/j.clinph.2013.02.029

S2-1. Intra-operative monitoring of MEP: Corticospinal MEP vs.cortico-muscular MEP—Takamitsu Yamamoto, Kazutaka Kobay-ashi, Hideki Oshima, Chikashi Fukaya, Yoichi Katayama (Dept.Neurological Surgery, Nihon University, Tokyo, Japan)

Corticospinal MEP (D-wave), cortico-muscular MEP in responseto direct motor cortex stimulation, and subcortico-spinal MEP (sub-cortical D-wave) in response to subcortical pyramidal tract stimula-tion were monitored in patients with brain tumors around the motorcortex who showed no obvious motor disturbance before the opera-tion. We could not establish the definite warning criteria of the cor-tico-muscular MEP, because disappeared cortico-muscular MEPreappeared during the operation. We concluded that cortico-muscu-lar MEP is a safety range monitoring, and cortico-muscular MEP canguarantee the preserved motor function if no obvious changeoccurred during the tumor resection. On the other hand, monitoringof the D-wave enabled the function of the corticospinal tract to beevaluated selectively. A decrease of less than 30% may indicate post-operative preservation of motor function, including transient motordisturbance with subsequent complete recovery. Monitoring of thesubcortical D-wave is useful to know the distance from the pyrami-dal tract. Intraoperative monitoring of D-wave and subcortical D-wave allows maximum resection of brain tumors located aroundthe motor cortex.

doi:10.1016/j.clinph.2013.02.030

S2-2. Intraoperative monitoring of motor evoked potential inaneurysm surgery: Transcranial or direct cortical stimulation?—Tatsuya Sasaki, Makoto Abe, Mizuho Inoue, Hiroki Uchida, Atsu-shi Saito, Hiroyuki Kon, Michiharu Nishijima (Aomori PrefecturalCentral Hospital, Aomori, Japan)

Object: We examined usefulness of transcranial (TC) stimulationfor motor evoked potential (MEP) in aneurysm surgery. Data of TCMEP were compared with those of direct cortical (DC) MEP whichhas been considered as gold standard for supratentorial lesions.

Method: Clinical materials were consecutive 122 patients (rup-tured 43, unruptured 79) who underwent aneurysmal clipping underboth TC and DC MEP monitoring. TC MEP was recorded every 10 minand stimulation strength was set +20% to threshold. After duralopening, the strip electrode with 16 electrodes was inserted subdur-ally. Stimulation strength was set +2 mA to threshold.

Results: TC MEP was recorded in all patients, while DC MEP couldnot be recorded in 15 patients mainly due to subdural resistance.Stimulation threshold of TC MEP was decreased after craniotomyand increased after CSF suction. In 14 patients both MEPs disap-peared after temporary occlusion or aneurismal clipping. In 12 bothMEP recovered after release of temporary occlusion or clipping. Inremaining 2 patients MEP re-appeared but amplitudes were signifi-cantly lower than the control. Consequently these two patientsdeveloped transient and slight hemiparesis.

Conclusion: TC MEP was recorded in all cases and revealed paral-lel changes with DC MEP, suggesting TC MEP alone is enough tomonitor MEP.

doi:10.1016/j.clinph.2013.02.031

S2-3. Intraoperative monitoring of lower extremity motor-evoked potential by direct cortical stimulation—Masami Fujii,Yuichi Maruta, Hirochika Imoto, Hisaharu Goto, Michiyasu Suzuki(Yamaguchi University School of Medicine, Yamaguchi-Ube,Japan)

The aim of this study was to establish a reliable lower-extremityMEP (LE-MEP) monitoring method using direct cortical stimulation(DCS). Intraoperative LE-MEP monitoring was performed in 87patients undergoing surgical procedures for aneurysms of the ante-rior cerebral artery or for brain tumors that were adjacent to themotor cortex of the lower extremities. After craniotomy, a subduralgrid or strip electrode was placed on the cortex so that the mostmedial contact was positioned 2 cm lateral from the midline onthe motor cortex. Using the medial contact, anodal-electrical mono-polar stimulation (cathode; Fpz) was performed with short trains offive stimuli. LE-MEPs were recorded from the lower-limb muscles.The LE-MEPs were successfully recorded in all patients and the dis-appearance or amplitude-reduction of MEP waveforms was observedin 19 patients (22%) during operative procedures. Adverse effectsregarding monitoring procedures were not observed. These resultsindicate that LE-MEP recording can be accomplished during supra-tentorial surgery using anodal monopolar DCS with a frontal cathodeand a subdural electrode placed on the convex side of the motor cor-tex close to the midline.

doi:10.1016/j.clinph.2013.02.032

S2-4. Facial motor evoked potentials elicited by transcranialelectrical stimulation for intraoperative monitoring—MasafumiFukuda, Makoto Oishi, Tetsuro Takao, Tetsuya Hiraishi, YukihikoFujii (Department of Neurosurgery, Niigata University, Niigata,Japan)

We have employed facial motor evoked potentials (FMEPs) elic-ited by transcranial electrical stimulation to monitor facial nervefunction during skull base surgery. Postoperative facial nerve func-tion correlated significantly with the final/baseline FMEP ratios inthe orbicularis oculi (n = 92, r = �0.68, p < 0.001) and orbicularis oris(n = 102, r = �0.74, p < 0.001). Patients (n = 29) who underwent sur-gery using both compound muscle action potential (CMAP) andFMEP monitorings had better facial nerve outcomes than those(n = 117) using only CMAP monitoring 1 year after surgery(p < 0.05). Proximal/distal amplitude ratios of CMAPs after vestibularschwannoma resection correlated significantly with final/baselineamplitude ratios of FMEPs in the orbicularis oculi (n = 15, r = 0.69,p < 0.005) and orbicularis oris (n = 15, r = 0.83, p < 0.001). These find-ings support that FMEP monitoring is useful for predicting facialnerve function postoperatively. FMEP monitoring has been also usedduring microvascular decompression for hemifacial spasm (HFS).Patients with reduction in FMEP amplitudes recorded for the orbic-ularis oculi muscle after decompression had relief of symptoms afterthe operation. FMEP monitoring may be useful in predicting thepostoperative outcomes in HFS patients as well as abnormal muscleresponse monitoring.

doi:10.1016/j.clinph.2013.02.033

e20 Society Proceedings / Clinical Neurophysiology 124 (2013) e19–e38