Hiroshi Shibasaki

Publications of Hiroshi Shibasaki

• Pathophysiology of unilateral asterixis due to thalamic lesion.

  Authors: Manabu Inoue, Yasuhiro Kojima, Tatsuya Mima, Nobukatsu Sawamoto, Masao Matsuhashi, Tomoyuki Fumuro, Masato Kinboshi, Satoko Koganemaru, Masutarou Kanda, Hiroshi Shibasaki

  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 03/2012;

  OBJECTIVE: Unilateral asterixis has been reported in patients with thalamic lesion. This study aims at elucidating the pathophysiology of the thalamic asterixis. METHODS: Two cases with unilateralOBJECTIVE: Unilateral asterixis has been reported in patients with thalamic lesion. This study aims at elucidating the pathophysiology of the thalamic asterixis. METHODS: Two cases with unilateral asterixis caused by an infarction in the lateral thalamus were studied by analysing the asterixis-related cortical activities, transcranial magnetic stimulation (TMS) for motor cortex excitability and probabilistic diffusion tractography for the thalamo-cortical connectivity. RESULTS: Averaging of electroencephalogram (EEG) time-locked to the asterixis revealed rhythmic oscillations of a beta band at the central area contralateral to the affected hand. TMS revealed a decrease in the motor evoked potential (MEP) amplitude and a prolongation of the silent period (SP). The anatomical mapping of connections between the thalamus and cortical areas using a diffusion-weighted image (DWI) showed that the lateral thalamus involved by the infarction was connected to the premotor cortex, the primary motor cortex (M1) and the primary somatosensory cortex (S1) of the corresponding hemisphere. CONCLUSIONS: The thalamic asterixis is mediated by the sensorimotor cortex, which is subjected to excessive inhibition as a result of the thalamic lesion involving the ventral lateral nucleus. SIGNIFICANCE: This is the first demonstration of participation of the sensorimotor cortex in the generation of asterixis due to the lateral thalamic lesion.

• An elderly case of moyamoya disease presenting with hemichorea.

  Authors: Masato Kinboshi, Manabu Inoue, Yasuhiro Kojima, Tomokazu Nakagawa, Masutaro Kanda, Hiroshi Shibasaki

  Rinshō shinkeigaku = Clinical neurology. 01/2012; 52(1):25-9.

  A 61-year-old Japanese female was admitted with sudden onset of choreic movements of the right extremities. MRI demonstrated no abnormality suggestive of acute infarcts. Cerebral angiography revealedA 61-year-old Japanese female was admitted with sudden onset of choreic movements of the right extremities. MRI demonstrated no abnormality suggestive of acute infarcts. Cerebral angiography revealed high-grade stenosis of bilateral middle cerebral arteries at the origin and abnormal vascular network compatible with moyamoya disease. Administration of low-dose haloperidol rapidly resolved the choreic movements. SPECT obtained one month after the clinical onset demonstrated increase of the regional cerebral blood flow (rCBF) in the left basal ganglia. Moyamoya disease presenting chorea as its initial symptom was only infrequently reported in the elderly. In the present case, increased rCBF in the basal ganglia and remarkable effect of a dopamine D2 blocker suggest functional abnormality of the corresponding striatum as an underlying cause of hemichorea.

• Parieto-frontal network in humans studied by cortico-cortical evoked potential.

  Authors: Riki Matsumoto, Dileep R Nair, Akio Ikeda, Tomoyuki Fumuro, Eric Lapresto, Nobuhiro Mikuni, William Bingaman, Susumu Miyamoto, Hidenao Fukuyama, Ryosuke Takahashi, Imad Najm, Hiroshi Shibasaki, Hans O Lüders

  Human brain mapping. 09/2011;

  Parieto-frontal network is essential for sensorimotor integration in various complex behaviors, and its disruption is associated with pathophysiology of apraxia and visuo-spatial disorders. DespiteParieto-frontal network is essential for sensorimotor integration in various complex behaviors, and its disruption is associated with pathophysiology of apraxia and visuo-spatial disorders. Despite advances in knowledge regarding specialized cortical areas for various sensorimotor transformations, little is known about the underlying cortico-cortical connectivity in humans. We investigated inter-areal connections of the lateral parieto-frontal network in vivo by means of cortico-cortical evoked potentials (CCEPs). Six patients with epilepsy and one with brain tumor were studied. With the use of subdural electrodes implanted for presurgical evaluation, network configuration was investigated by tracking the connections from the parietal stimulus site to the frontal site where the maximum CCEP was recorded. It was characterized by (i) a near-to-near and distant-to-distant, mirror symmetric configuration across the central sulcus, (ii) preserved dorso-ventral organization (the inferior parietal lobule to the ventral premotor area and the superior parietal lobule to the dorsal premotor area), and (iii) projections to more than one frontal cortical sites in 56% of explored connections. These findings were also confirmed by the standardized parieto-frontal CCEP connectivity map constructed in reference to the Jülich cytoarchitectonic atlas in the MNI standard space. The present CCEP study provided an anatomical blueprint underlying the lateral parieto-frontal network and demonstrated a connectivity pattern similar to non-human primates in the newly developed inferior parietal lobule in humans. Hum Brain Mapp, 2011. © 2011 Wiley-Liss, Inc.

• Cortical activities associated with voluntary movements and involuntary movements.

  Authors: Hiroshi Shibasaki

  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 09/2011; 123(2):229-43.

  Recent advance in non-invasive techniques including electrophysiology and functional neuroimaging has enabled investigation of control mechanism of voluntary movements and pathophysiology ofRecent advance in non-invasive techniques including electrophysiology and functional neuroimaging has enabled investigation of control mechanism of voluntary movements and pathophysiology of involuntary movements in human. Epicortical recording with subdural electrodes in epilepsy patients complemented the findings obtained by the non-invasive techniques. Before self-initiated simple movement, activation occurs first in the pre-supplementary motor area (pre-SMA) and SMA proper bilaterally with some somatotopic organisation, and the lateral premotor area (PMA) and primary motor cortex (M1) mainly contralateral to the movement with precise somatotopic organisation. Functional connectivity among cortical areas has been disclosed by cortico-cortical coherence, cortico-cortical evoked potential, and functional MRI. Cortical activities associated with involuntary movements have been studied by jerk-locked back averaging and cortico-muscular coherence. Application of transcranial magnetic stimulation helped clarifying the state of excitability and inhibition in M1. The sensorimotor cortex (S1-M1) was shown to play an important role in generation of cortical myoclonus, essential tremor, Parkinson tremor and focal dystonia. Cortical myoclonus is actively driven by S1-M1 while essential tremor and Parkinson tremor are mediated by S1-M1. 'Negative motor areas' at PMA and pre-SMA and 'inhibitory motor areas' at peri-rolandic cortex might be involved in the control of voluntary movement and generation of negative involuntary movements, respectively.

• Increased cortical hyperexcitability and exaggerated myoclonus with aging in benign adult familial myoclonus epilepsy.

  Authors: Takefumi Hitomi, Akio Ikeda, Takayuki Kondo, Hisaji Imamura, Morito Inouchi, Riki Matsumoto, Kiyohito Terada, Masutaro Kanda, Masao Matsuhashi, Takashi Nagamine, Hiroshi Shibasaki, Ryosuke Takahashi

  Movement disorders : official journal of the Movement Disorder Society. 04/2011; 26(8):1509-14.

  The clinical implications of enlarged early cortical components of somatosensory evoked potentials in benign adult familial myoclonus epilepsy remain unknown. Somatosensory evoked potentialsThe clinical implications of enlarged early cortical components of somatosensory evoked potentials in benign adult familial myoclonus epilepsy remain unknown. Somatosensory evoked potentials following electrical stimulation of the median nerve at the wrist were studied in 16 patients with a clinical diagnosis of benign adult familial myoclonus epilepsy (7 men and 9 women; mean age, 51 ± 18 years) and 19 age-matched apparently healthy control subjects (11 men and 8 women; mean age, 49 ± 18 years). Giant somatosensory evoked potentials were observed in 13 of the 16 patients. P25 and N35 amplitudes in the patient group were 11.4 ± 6.1 and 19.2 ± 11.5 μV, respectively, and both were significantly larger compared with those in control subjects (P = 0.008 for P25 and P < 0.0001 for N35). There was a significant positive relationship between age at somatosensory evoked potential examination and N20, P25, and N35 amplitudes, both in the patient and in the control groups (P < 0.05). The linear regression gradient of the N35 amplitude with respect to age was significantly larger in the patient group than in the control group (P = 0.04). Furthermore, regression analysis showed a significant positive relationship between the myoclonus rating scale and age at time of somatosensory evoked potential examination (R = 0.645, P = 0.007). Somatosensory evoked potential amplitude increased with age in patients with benign adult familial myoclonus epilepsy to a greater extent than in the control subjects, which suggests a progressive increase in cortical excitability based on progressive pathophysiology in benign adult familial myoclonus epilepsy.

• Automatic interpretation of hyperventilation-induced electroencephalogram constructed in the way of qualified electroencephalographer's visual inspection.

  Authors: Xiu Zhang, Xingyu Wang, Takenao Sugi, Akio Ikeda, Takashi Nagamine, Hiroshi Shibasaki, Masatoshi Nakamura

  Medical & biological engineering & computing. 10/2010; 49(2):171-80.

  Quantitative analysis and detection of electroencephalogram (EEG) recordings during evoked activities is essential for clinical diagnosis on neurological disorders. However, the process ofQuantitative analysis and detection of electroencephalogram (EEG) recordings during evoked activities is essential for clinical diagnosis on neurological disorders. However, the process of interpreting EEG is time consuming for electroencephalographers (EEGers). In this study, an automatic EEG interpretation system constructed in the way of qualified EEGer's visual inspection was proposed. The system was applied to interpret hyperventilation-induced EEG automatically. The final results of automatic interpretation were compared with EEGer's visual inspection, and showed high consistence.

• [A case of Guillain-Barré syndrome accompanied by syndrome of inappropriate secretion of antidiuretic hormone].

  Authors: Manabu Inoue, Yasuhiro Kojima, Yoshitomo Shirakashi, Masutarou Kanda, Hiroshi Shibasaki

  Rinshō shinkeigaku = Clinical neurology. 10/2010; 50(10):710-3.

  A 73-year-old Japanese male was admitted because of difficulty in standing up after acute upper respiratory inflammation with mild fever followed by watery diarrhea. Neurological examination revealedA 73-year-old Japanese male was admitted because of difficulty in standing up after acute upper respiratory inflammation with mild fever followed by watery diarrhea. Neurological examination revealed moderate proximal muscle weakness and loss of tendon reflexes in all extremities. The blood sodium level was 106 mEq/l on admission. The blood level of antidiuretic hormone (ADH), renin and aldsterone was 11.3 pg/ml (normal value 0.3-4.2), 0.2 ng/ml/h (0.2-2.7) and less than 10.0 pg/ml (38.9-307.0), respectively. The plasma osmolarity was 221 mOsm/kg (270-295), and the urine osmolarity was 416 mOsm/kg (50-1400). EMG and nerve conduction studies suggested acute demyelination in the motor and sensory nerves. CSF revealed 10 cells/mm3 and elevated protein to 98 mg/dl. The clinical course, laboratory data and electrophysiological findings suggested coexistence of the syndrome of inappropriate secretion of ADH (SIADH) and Guillain-Barré syndrome (GBS) from the very early clinical stage of the diseases. The clinical and laboratory findings improved after intravenous administration of saline over three weeks. When GBS is associated with SIADH, hyponatremia is commonly seen at the peak of motor paralysis, often accompanied by autonomic or respiratory failure requiring mechanical ventilation. This was not the case in the present patient. It is postulated that SIADH, like GBS, might be caused by an autoimmune mechanism.

• How does voluntary movement stop resting tremor?

  Authors: Masako Kinoshita, Takefumi Hitomi, Masao Matsuhashi, Tomokazu Nakagawa, Takashi Nagamine, Hideyuki Sawada, Hidemoto Saiki, Hiroshi Shibasaki, Ryosuke Takahashi, Akio Ikeda

  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 03/2010; 121(6):983-5.

• Automatic Reference Selection for Quantitative EEG Component Interpretation: Cross Spectrum Analysis Based on Bipolar EEG.

  Authors: Bei Wang, Xingyu Wang, Akio Ikeda, Takashi Nagamine, Hiroshi Shibasaki, Takenao Sugi, Masatoshi Nakamura

  Artificial Intelligence and Computational Intelligence - International Conference, AICI 2010, Sanya, China, October 23-24, 2010, Proceedings, Part II; 01/2010

• Impairment of the cortical GABAergic inhibitory system in catatonic stupor: a case report with neuroimaging.

  Authors: Kazumi Iseki, Akio Ikeda, Takeshi Kihara, Yasuhiro Kawamoto, Takahiro Mezaki, Takashi Hanakawa, Kazuo Hashikawa, Hidenao Fukuyama, Hiroshi Shibasaki

  Epileptic disorders : international epilepsy journal with videotape. 07/2009; 11(2):126-131.

  We report the case of a 32-year-old patient who presented with catatonic stupor during the course of acute aseptic encephalitis involving the right frontotemporal area. Flumazenil-PET performedWe report the case of a 32-year-old patient who presented with catatonic stupor during the course of acute aseptic encephalitis involving the right frontotemporal area. Flumazenil-PET performed during the stupor indicated decreased benzodiazepine receptor binding in the right frontotemporal area where glucose metabolism was preserved as revealed by FDG-PET. An injection of diazepam immediately ameliorated catatonic symptoms and reduced widespread high amplitude slow EEG activities with right frontotemporal predominance. Compared with a SPECT study performed a week earlier, there was no abnormal right-sided anteriorly predominant cerebral hyperperfusion after injection of diazepam. While neither flumazenil- nor FDG-PET could be repeated, and with the caveat that generalized convulsions occurred initially and epilepsia partialis continua was present for two weeks starting on the 23rd day after illness onset, these findings suggest that in our case the presentation with catatonic stupor may be related to impairment of the cortical GABAergic inhibitory system.

• Temporal Dynamics of Japanese Morphogram and Syllabogram Processing in the Left Basal Temporal Area Studied by Event-Related Potentials.

  Authors: Keiko Usui, Akio Ikeda, Takashi Nagamine, Masao Matsuhashi, Masako Kinoshita, Nobuhiro Mikuni, Susumu Miyamoto, Nobuo Hashimoto, Hidenao Fukuyama, Hiroshi Shibasaki

  Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society. 06/2009;

  SUMMARY:: Visual language processing in the left basal temporal area (LBTA) was investigated using subdural electrodes in two patients with medically intractable temporal lobe epilepsy. Reading ofSUMMARY:: Visual language processing in the left basal temporal area (LBTA) was investigated using subdural electrodes in two patients with medically intractable temporal lobe epilepsy. Reading of Japanese syllabogram (kana) and morphogram (kanji) both provoked two types of event-related potentials, one with the peak latency of approximately 200 milliseconds and the other approximately 300 milliseconds, at the anterior and posterior portion of the fusiform, parahippocampal, and inferior temporal gyri within LBTA. By electrical stimulation using the same electrodes, in contrast, kana reading was selectively impaired in one area in the posterior portion of LBTA where a sharp event-related potential was recorded at approximately 200 milliseconds, and kanji reading was selectively impaired in another area also in the posterior portion of LBTA, where a blunt event-related potential was recorded at approximately 300 milliseconds. Because kana reading is functionally fundamental compared with kanji reading, relatively early signals at 200 milliseconds might be related to postperceptual but still fundamental functions such as letter-by-letter language processing and relatively late signals at 300 milliseconds might be associated with postperceptual, relatively higher-order functions such as word-as-a-whole language processing. The results indicate the existence of two distinct functional areas for written-language processing within LBTA. Both kanji and kana signals reach specific area at the same timing.

• Negative motor seizure arising from the negative motor area: Is it ictal apraxia?

  Authors: Akio Ikeda, Ken-Ichi Hirasawa, Masako Kinoshita, Takefumi Hitomi, Riki Matsumoto, Takahiro Mitsueda, Jun-Ya Taki, Moritoh Inouch, Nobuhiro Mikuni, Tomokatsu Hori, Hidenao Fukuyama, Nobuo Hashimoto, Hiroshi Shibasaki, Ryosuke Takahashi

  Epilepsia. 06/2009;

  Summary Purpose: Seizure manifesting motor arrest, that is, negative motor seizure (NMS), is a rare epileptic condition in which only inability to conduct voluntary movements or praxis is produced,Summary Purpose: Seizure manifesting motor arrest, that is, negative motor seizure (NMS), is a rare epileptic condition in which only inability to conduct voluntary movements or praxis is produced, although consciousness is preserved. The negative motor area (NMA) seems to be responsible, but its generator mechanism has not yet been clarified. Patients and Methods: Three patients manifesting NMS were investigated. Two patients (ages 33 and 17) with intractable frontal lobe epilepsy had subdural grid implantation for epilepsy surgery, and one (age 77) had scalp electroencephalography (EEG) monitoring. Results: Ictal semiologies commonly observed, at least in the two patients, were found as follows; (1) indescribable or ill-localized aura, (2) repetitive involuntary vocalization, (3) inability to speak, (4) inability to move the extremities, and (5) subsequent evolution to positive motor seizures. Awareness and comprehension were preserved throughout the episode before generalized seizures. In two patients with epicortical EEG recording, ictal activity arose from the lateral NMA in one, and from the rostral supplementary motor area in the other. Cortical stimulation at NMA in one patient elicited symptoms identical to NMS. Another patient had scalp EEG and magnetic resonance imaging (MRI) abnormality, both suggesting the epileptogenic focus in the mesial frontal area. Conclusion: We showed that (1) NMS was a rare condition in patients with seizure focus in the frontal lobe, and (2) that the NMA was responsible for the symptoms. The documented state in the present study may reflect ictal apraxia, but it requires further investigation.

• Automatic Interpretation of Dominant Rhythm in Awake Electroencephalogram Based on Coherence and Phase Analysis for Bipolar Derivation.

  Authors: Xiu Zhang, Xingyu Wang, Takashi Nagamine, Takenao Sugi, Hiroshi Shibasaki, Akio Ikeda, Masatoshi Nakamura

  Proceedings of the 2nd International Conference on BioMedical Engineering and Informatics, BMEI 2009, October 17-19, 2009, Tianjin, China; 01/2009

• Bipolar EEG Analysis Based on Cross Spectrum: Focal Detection of Slowing Wave for Automatic EEG Interpretation.

  Authors: Bei Wang, Takenao Sugi, Xingyu Wang, Akio Ikeda, Takashi Nagamine, Hiroshi Shibasaki, Masatoshi Nakamura

  Proceedings of the 2nd International Conference on BioMedical Engineering and Informatics, BMEI 2009, October 17-19, 2009, Tianjin, China; 01/2009

• [A case of Bickerstaff brainstem encephalitis concomitant with axonal Guillain-Barre syndrome and ballism successfully treated with intravenous immunoglobulin treatment]

  Authors: Fumi Makino, Yasuhiro Kojima, Manabu Inoue, Hitoshi Satoi, Masutaro Kanda, Hiroshi Shibasaki, Susumu Kusunoki

  Rinshō shinkeigaku = Clinical neurology. 08/2008; 48(7):501-4.

  A 39-year-old man acutely developed diplopia, vertigo, unsteady gait, and disturbance of consciousness following an upper respiratory infection. Neurological examination showed ophthalmoplegia,A 39-year-old man acutely developed diplopia, vertigo, unsteady gait, and disturbance of consciousness following an upper respiratory infection. Neurological examination showed ophthalmoplegia, facial paralysis, tetraplegia and loss of deep tendon reflexes. Babinski reflex was positive on the left and there were bilateral flexor withdrawal reflexes. He also developed ballism-like involuntary movements in all extremities, loss of proprioception predominantly on the left, and severe truncal ataxia. Anti-GQ1b IgG antibody was selectively elevated in serum, and CSF protein was elevated to 53 mg/dl with cell count of 12/mm3. Nerve conduction study showed decreased amplitude of compound motor action potentials in all extremities, and no response in facial muscles. Cranial MRI showed no abnormalities whereas EEG was severely abnormal with lack of posterior dominant rhythm and the presence of continuous diffuse theta-waves. This case presented clinical characteristics of three syndromes concurrently-Fisher syndrome, Bickerstaff brainstem encephalitis, and Guillain-Barré syndrome-that may be collectively called 'anti-GQ1b IgG antibody syndrome'. The unique feature of the present case was development of deep coma and ballism-like movements, associated with selective increase of serum anti-GQ1b IgG antibody. It is thus conceivable that anti-GQ1b IgG antibody might underlie the pathogenesis of all three conditions.

• Efficacy of low-dose, add-on therapy of clobazam (CLB) is produced by its major metabolite, N-desmethyl-CLB.

  Authors: Masako Kinoshita, Akio Ikeda, Tahamina Begum, Kiyohito Terada, Hiroshi Shibasaki

  Journal of the neurological sciences. 01/2008; 263(1-2):44-8.

  We evaluated the efficacy of low-dose, add-on therapy of CLB in adults with refractory epilepsy. 28 patients were included: 12 with temporal lobe epilepsy (TLE), 14 with extratemporal lobe epilepsyWe evaluated the efficacy of low-dose, add-on therapy of CLB in adults with refractory epilepsy. 28 patients were included: 12 with temporal lobe epilepsy (TLE), 14 with extratemporal lobe epilepsy (ETLE) and 2 with symptomatic generalized epilepsy (SGE). CLB was added with the initial dose of 2.5 mg/day and increased to the optimal dose (mean, 5.6 mg/day). The mean observation period was 7.9 months. As compared with the baseline period, 14 out of 28 patients (50%) obtained an obviously good seizure control: 6 seizure free and 8 more than 50% of seizure reduction. The 14 patients comprised of 4 TLE, 8 ETLE and 2 SGE. In seizure type analysis, 26% of complex partial seizures (CPS), 64% of simple partial seizures (SPS) and 86% of generalized tonic-clonic seizures (GTC) showed a good control. Blood level of N-desmethyl-CLB in the steady state was higher in seizure-free group of 6 patients, and N-desmethyl-CLB blood level/dose per kg body weight correlated significantly to seizure control (p=0.0167). Our data show that even in low dose CLB was effective to patients with refractory epilepsy who had higher blood level of N-desmethyl-CLB.

• Use of magnetoencephalography in the presurgical evaluation of epilepsy patients.

  Authors: Hiroshi Shibasaki, Akio Ikeda, Takashi Nagamine

  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 08/2007; 118(7):1438-48.

  Magnetoencephalography (MEG) is used twofold for presurgical evaluation of patients with medically intractable partial epilepsy; to identify epileptogenic focus and to investigate functions ofMagnetoencephalography (MEG) is used twofold for presurgical evaluation of patients with medically intractable partial epilepsy; to identify epileptogenic focus and to investigate functions of cortical areas at or near the epileptogenic focus or structural lesion. For the precise localization of the current source of epileptic discharge, the question as to whether MEG is superior to electroencephalography (EEG) is often addressed. To answer this question, so many factors, both biologically and technically related, have to be taken into consideration. The biological factors include the magnitude of epileptic discharge, its distribution over the cortex, depth of its source from the head surface, and the proportion of large pyramidal neurons tangentially oriented with respect to the head surface within the cortical area. The technical factors include the quality of the recording instrument such as the number of sensors and the use of gradiometer vs. magnetometer, the employed method of source analysis, and availability of experts in each institute. As far as the importance of ictal recording is emphasized, long-term video/EEG monitoring is of utmost importance. Thus, it is concluded that, once the epileptogenic focus is identified by the video/EEG monitoring, then MEG is superior to EEG in order to precisely localize the current source of the interictal epileptic discharge. Another question often addressed is whether MEG can replace the invasive intracranial EEG recording or not. In addition to the above-described factors, different coverage of the cortical areas by MEG vs. invasive intracranial EEG recording has to be taken into account to explain some of the recent reports related to this question. MEG can be effectively applied to the investigation of cortical functions near the epileptogenic focus. It is especially so when combined with other non-invasive studies like functional magnetic resonance imaging (fMRI). In addition to the source analysis of magnetic fields related to various events or tasks, analysis of the task-related change of rhythmic cortical oscillations is a useful tool for studying higher cortical functions such as language in the presurgical evaluation.

• [A case presenting with both features of essential tremor and Parkinson tremor]

  Authors: Manabu Inoue, Tatsuya Mima, Yasuhiro Kojima, Hitoshi Satoi, Fumi Makino, Masutarou Kanda, Hiroshi Shibasaki

  Rinshō shinkeigaku = Clinical neurology. 08/2007; 47(7):413-8.

  A 78-year-old woman had postural and action tremor in hands since age of late 20's, though without much difficulty in daily living. Since age 76, she has had an increasing difficulty in walking andA 78-year-old woman had postural and action tremor in hands since age of late 20's, though without much difficulty in daily living. Since age 76, she has had an increasing difficulty in walking and postural balance, with some worsening of hand shaking as well. She also noted to have head shaking, involuntary movements in the mouth, and some difficulty in swallowing. Reportedly both of her parents and her brother had hand tremor. Neurologically she had resting, postural and action tremors in hands more on the left. She also had marked rigidity in the neck and moderate cogwheel rigidity in all limbs more on the left, moderate bradykinesia, markedly stooped posture with relatively wide base, slow and small-paced gait, and poor postural balance more posteriorly. Thus, it is most likely that the present case suffered from essential tremor and later developed Parkinson disease. Power spectrum analyses of surface electromyogram and accelerometer showed the peaks at 4.3 Hz for the resting tremor, and 3.1 and 5.2 Hz for the postural tremor. Furthermore, significant EEG-EMG coherence was seen at the peaks of 4.3 and 5.2 Hz, suggesting possible involvement of sensori-motor cortex for generation of both tremors. When the postural tremor was loaded with 500 g weight, the peak of power spectrum and EEG-EMG coherence showed the broader pattern with the maximal peak at 4.3 Hz, exactly the same frequency as that of the resting tremor. These findings may be explained by postulating that the 4.3 Hz peak of the resting tremor became apparent by loading because 5.2 Hz peak of the postural tremor was suppressed by the loading. The peak of the postural tremor at 3.1 Hz which was not detected by EEG-EMG coherence suggested that the tremor for 3.1 Hz was not involved to sensori-motor cortex for generation.

• [Concurrence of myasthenia gravis, polymyositis, thyroiditis and eosinophilia in a patient with type B1 thymoma]

  Authors: Manabu Inoue, Yasuhiro Kojima, Akiyo Shinde, Hitoshi Satoi, Fumi Makino, Masutarou Kanda, Hiroshi Shibasaki

  Rinshō shinkeigaku = Clinical neurology. 08/2007; 47(7):423-8.

  We presented a 43-year-old Japanese woman who acutely developed weakness of all extremities and difficulty in swallowing and drooping of eyelids, characterized by easy fatigability at the end ofWe presented a 43-year-old Japanese woman who acutely developed weakness of all extremities and difficulty in swallowing and drooping of eyelids, characterized by easy fatigability at the end of December, 2005. On general physical examination, she had moderate goiter. No cervical lymphadenopathy, cardiac murmur, or skin rash was noted. Neurologically, she had blepharoptosis, more on the right, only in the upright position with easy fatigability and marked weakness in the neck flexor, trunk, and all limb muscles much more proximally than distally. She had neither muscular atrophy nor upper motor neuron sign. Laboratory data showed slight leukocytosis with eosinophilia (up to 31%), and serum creatine kinase was markedly increased to over 2,000 IU/l. TSH receptor antibody (11.9%) and anti-acetylcholine receptor antibody (46.6 nmol/L) were also increased. Edrophonium test was positive. Electrophysiologically, muscle evoked potentials by repetitive motor nerve stimulation showed 13% and 50% waning in abductor pollicis brevis and deltoid muscle, respectively, at low frequency and no waxing at high frequency. Needle EMG showed fibrillation potentials and positive sharp waves in proximal muscles. Polymyositis was diagnosed by muscle biopsy which showed infiltration of lymphocytes in the endomysium and around non-necrotic muscle fibers. Upper arm muscle MRI showed multifocal high signal intensity lesions on T2-weighted images which were likely related to myositis. This finding is atypical for polymyositis. X-ray and CT of chest showed a mass lesion in the left pulmonary hilum, which was histologically diagnosed as type B1 thymoma. Thus, the present case had myasthenia gravis, polymyositis, thyroidititis and eosinophilia associated with type B1 thymoma. After the thymectomy, corticosteroid administration and immunoadsorption therapy, clinical symptoms and all laboratory abnormalities markedly improved.

• Dynamic change of proximal conduction in demyelinating neuropathies: a cervical magnetic stimulation combined with maximum voluntary contraction.

  Authors: Takefumi Hitomi, Ryuji Kaji, Nagako Murase, Nobuo Kohara, Takahiro Mezaki, Hiroyuki Nodera, Takashi Kawamura, Akio Ikeda, Hiroshi Shibasaki

  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 04/2007; 118(4):741-50.

  OBJECTIVE: To evaluate conduction abnormalities in the nerves innervating the proximal muscles in demyelinating neuropathies (DN) using cervical magnetic stimulation. METHODS: We applied cervicalOBJECTIVE: To evaluate conduction abnormalities in the nerves innervating the proximal muscles in demyelinating neuropathies (DN) using cervical magnetic stimulation. METHODS: We applied cervical root magnetic stimulation in the biceps brachii muscles and examined its activity-dependent conduction changes produced by maximal voluntary contraction (MVC) in 12 DN patients (seven chronic inflammatory demyelinating polyradiculoneuropathy and five multifocal motor neuropathy), six motor neuron disease (MND) patients, and 12 healthy volunteers. RESULTS: Defining the upper normal limit of motor threshold (31%) and latency (6.7 ms) of the compound muscle action potential (CMAP) as mean+2SD, most DN patients revealed an abnormality in motor threshold (10/12) and latency (11/12) in contrast to MND patients (motor threshold (1/6) and latency (0/6)). These parameters contribute to the differentiation of DN from MND (P<0.01). Furthermore, the MVC maneuver transiently decreased the CMAP amplitude ratio (after MVC/before MVC x 100) in DN (83+/-18 %) compared with MND (P<0.01). Two of three DN patients who showed normal motor threshold or latency as in MND were successfully differentiated from MND by the MVC maneuver. CONCLUSIONS: In DN patients, conduction abnormality in the nerves innervating the proximal muscles was revealed by cervical magnetic stimulation combined with the MVC maneuver. SIGNIFICANCE: Our results suggested that conduction abnormalities in the proximal nerves innervating the proximal muscles could be evaluated by this method.