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Y Terao,
Y Ugawa,
R Hanajima,
K Machii,
T Furubayashi,
H Mochizuki,
H Enomoto,
Y Shiio, H Uesugi,
N K Iwata,
I Kanazawa
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ABSTRACT: The purpose of this method is to establish a single motor unit recording technique to study the differential activation of corticospinal volleys by various types of transcranial magnetic stimulation (TMS). TMS is performed with various coil orientations over the hand or leg motor areas and surface EMG, and single motor unit recordings are made either from the studied hand or leg muscle. Transcranial electrical stimulation (TES) is also performed over the motor cortex as well as at the foramen magnum level to determine the latency of D waves. The intensity of stimulation is set just above the motor threshold for each type of stimulation. This method makes it possible to activate some I volleys (especially I1 and I3 waves) preferentially, if not selectively, from the hand and leg motor areas. The obtained results accord well with recent epidural recording studies, which lends support to the validity of this method.
Brain Research Protocols 05/2001; 7(1):61-7. · 1.82 Impact Factor
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ABSTRACT: 1. We investigated interhemispheric interactions between the human hand motor areas using transcranial cortical magnetic and electrical stimulation. 2. A magnetic test stimulus was applied over the motor cortex contralateral to the recorded muscle (test motor cortex), and an electrical or magnetic conditioning stimulus was applied over the ipsilateral hemisphere (conditioning motor cortex). We investigated the effects of the conditioning stimulus on responses to the test stimulus. 3. Two effects were elicited at different interstimulus intervals (ISIs): early facilitation (ISI = 4-5 ms) and late inhibition (ISI > or = 11 ms). 4. The early facilitation was evoked by a magnetic or anodal electrical conditioning stimulus over the motor point in the conditioning hemisphere, which suggests that the conditioning stimulus for early facilitation directly activates corticospinal neurones. 5. The ISIs for early facilitation taken together with the time required for activation of corticospinal neurones by I3-waves in the test hemisphere are compatible with the interhemispheric conduction time through the corpus callosum. Early facilitation was observed in responses to I3-waves, but not in responses to D-waves nor to I1-waves. Based on these results, we conclude that early facilitation is mediated through the corpus callosum. 6. If the magnetic conditioning stimulus induced posteriorly directed currents, or if an anodal electrical conditioning stimulus was applied over a point 2 cm anterior to the motor point, then we observed late inhibition with no early facilitation. 7. Late inhibition was evoked in responses to both I1- and I3-waves, but was not evoked in responses to D-waves. The stronger the conditioning stimulus was, the greater was the amount of inhibition. These results are compatible with surround inhibition at the motor cortex.
The Journal of Physiology 04/2001; 531(Pt 3):849-59. · 4.72 Impact Factor
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ABSTRACT: To compare voluntary single fiber electromyography (v-SFEMG) and repetitive nerve stimulation (RNS) at the same extensor digitorum communis (EDC) muscle in myasthenia gravis (MG).
We examined v-SFEMG and RNS successively on the same day in the same EDC muscle. We studied 45 examinations of both v-SFEMG and RNS in 29 patients suffering from MG, together with examinations of RNS in 30 control subjects.
Forty-one of 45 (91%) v-SFEMGs showed abnormal results, whereas only 18/45 (40%) RNSs showed an abnormal decrement. The percentage of decrement showed similar correlations with 3 v-SFEMG parameters: percentage of abnormal pairs, percentage of blocking pairs, and the mean MCD value. Examinations showing a significant decrement in RNS had at least 60%, and usually no less than 90%, abnormal pairs, and 10-80% blocking pairs. Some muscles without a decrement had up to 50% blocking pairs.
These results suggest that the blocking phenomenon observed in v-SFEMG is not a direct counterpart of the decrement in RNS. This must be partly because fibers contributing to the decrement are continuously blocked during voluntary contraction, and partly, because smaller motor units explored by v-SFEMG are probably more abnormal in MG than larger motor units mainly contributing to a decrement. Both factors make v-SFEMG much more sensitive than RNS.
Clinical Neurophysiology 03/2001; 112(2):300-3. · 3.41 Impact Factor
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ABSTRACT: We investigated the presence of human herpesvirus 6 (HHV-6) and herpes simplex virus (HSV) in surgical tissue from temporal lobe epileptic patients. A total of 17 cases were studied, including eight males and nine females. The mean age was 24.9 +/- 11.1 years and the mean age of onset was 11.1 +/- 5.4 years. Five patients were diagnosed as encephalitis/meningitis and another three had a history of suspected encephalitis/meningitis, but no patient showed any obvious neurological symptom or mental handicap. Mesial and lateral temporal tissues were examined by polymerase chain reaction. Among six patients positive for HHV-6 (35%), the mesial temporal lobe was positive in four and the lateral temporal lobe was positive in three. Herpes simplex virus was positive in only one patient. Three of the six patients positive for HHV-6 did not show any apparent causes. Mild encephalitis/meningitis induced by HHV-6, a condition sometimes not recognized as encephalitis/meningitis, may be one of the most frequent causes of temporal lobe epilepsy.
Psychiatry and Clinical Neurosciences 11/2000; 54(5):589-93. · 2.13 Impact Factor
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Y Terao,
Y Ugawa,
R Hanajima,
K Machii,
T Furubayashi,
H Mochizuki,
H Enomoto,
Y Shiio, H Uesugi,
N K Iwata,
I Kanazawa
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ABSTRACT: We performed transcranial magnetic stimulation (TMS) to elucidate the D- and I-wave components comprising the motor evoked potentials (MEPs) elicited from the leg motor area, especially at near-threshold intensity. Recordings were made from the tibialis anterior muscle using needle electrodes. A figure-of-eight coil was placed so as to induce current in the brain in eight different directions, starting from the posterior-to-anterior direction and rotating it in 45 degrees steps. The latencies were compared with those evoked by transcranial electrical stimulation (TES) and TMS using a double cone coil. Although the latencies of MEPs ranged from D to I3 waves, the most prominent component evoked by TMS at near-threshold intensity represented the I1 wave. With the double cone coil, the elicited peaks always represented I1 waves, and D waves were evoked only at very high stimulus intensities, suggesting a high effectiveness of this coil in inducing I1 waves. Using the figure-of-eight coil, current flowing anteriorly or toward the hemisphere contralateral to the recorded muscle was more effective in eliciting large responses than current flowing posteriorly or toward the ipsilateral hemisphere. The effective directions induced I1 waves with the lowest threshold, whereas the less effective directions elicited I1 and I2 waves with a similar frequency. Higher stimulus intensities resulted in concomitant activation of D through I3 waves with increasing amount of D waves, but still the predominance of I1 waves was apparent. The amount of I waves, especially of I1 waves, was greater than predicted by the hypothesis that TMS over the leg motor area activates the output cells directly, but rather suggests predominant transsynaptic activation. The results accord with those of recent human epidural recordings.
Brain Research 04/2000; 859(1):137-46. · 2.73 Impact Factor
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T Furubayashi,
Y Ugawa,
Y Terao,
R Hanajima,
K Sakai,
K Machii,
H Mochizuki,
Y Shiio, H Uesugi,
H Enomoto,
I Kanazawa
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ABSTRACT: To study the effect of a loud auditory stimulus on the excitability of the human motor cortex.
Ten normal volunteers participated in this study. The size of responses to transcranial magnetic or electrical cortical stimulation (TMS or TES) given at different times (ISIs) after a loud sound were compared with those to TMS or TES alone (control response). Different intensities and durations of sound were used at several intertrial intervals (ITIs). In addition, we examined how the presence of a preceding click modulated the effect of a loud sound (prepulse inhibition). The incidence of startle response evoked by various stimuli was also studied.
A loud auditory stimulus suppressed EMG responses to TMS when it preceded the magnetic stimulus by 30-60 ms, whereas it did not affect responses to TES. This suggests that the suppression occurred at a cortical level. Significant suppression was evoked only when the sound was louder than 80 dB and longer than 50 ms in duration. Such stimuli frequently elicited a startle response when given alone. The effect was not evoked if the ITI was 5 s, but was evoked when it was longer than 20 s. A preceding click reduced the suppression elicited by loud sounds.
Auditory stimuli that produced the greatest effect on responses to TMS had the same characteristics as those which yielded the most consistent auditory startle. We suggest that modulation of cortical excitability occurs in parallel with the auditory startle and both may arise from the same region of the brain-stem.
Clinical Neurophysiology 02/2000; 111(1):178-83. · 3.41 Impact Factor
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Y Terao,
Y Ugawa,
R Hanajima,
T Furubayashi,
K Machii,
H Enomoto,
Y Shiio,
H Mochizuki, H Uesugi,
Y Uesaka,
I Kanazawa
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ABSTRACT: Air-puff stimulation applied to a fingertip is known to exert a location-specific facilitatory effect on the size of the motor evoked potentials elicited in hand muscles by transcranial magnetic stimulation. In order to clarify its nature and the pathway responsible for its generation, we studied 27 patients with discrete lesions in the brain (16, 9 and 2 patients with lesions in the cerebral cortex, thalamus and brainstem, respectively). Facilitation was absent in patients with lesions affecting the primary sensorimotor area, whereas it was preserved in patients with cortical lesions that spared this area. Facilitation was abolished with thalamic lesions that totally destroyed the nucleus ventralis posterolateralis (VPL), but was preserved with lesions that at least partly spared it. Lesions of the spinothalamic tract did not impair facilitation. The size of the N20-P25 component of the somatosensory evoked potential showed a mild correlation with the amount of facilitation. The facilitation is mainly mediated by sensory inputs that ascend the dorsal column and reach the cortex through VPL. These are fed into the primary motor area via the primary sensory area, especially its anterior portion, corresponding to Brodmann areas 3 and 1 (possibly also area 2), without involving other cortical regions. The spinothalamic tract and direct thalamic inputs into the motor cortex do not contribute much to this effect. Some patients could generate voluntary movements despite the absence of the facilitatory effect. The present method will enable us to investigate in humans the function of one of the somatotopically organized sensory feedback input pathways into the motor cortex, and will be useful in monitoring ongoing finger movements during object manipulation.
Brain 01/2000; 122 ( Pt 12):2259-77. · 9.46 Impact Factor
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K Machii,
Y Ugawa,
Y Terao,
R Hanajima,
T Furubayashi,
H Mochizuki,
Y Shiio,
H Enomoto, H Uesugi,
S Kuzuhara,
I Kanazawa
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ABSTRACT: A well-organized input-output relation similar to that of the monkey motor cortex has been demonstrated in the human hand motor area (Terao Y, Ugawa Y, Uesaka Y, Hanajima R, Gemba-Shimizu K, Ohki Y, Kanazawa I. Input-output organization in the hand area of the human motor cortex, Electroenceph clin Neurophysiol 1995;97:375-381). The aim of this study is to investigate the input-output organization of the human foot motor area.
We studied the effect of tactile stimuli given to the toe tip on the sizes of following responses; motor evoked potentials (MEPs) elicited by transcranial magnetic or electrical stimulation (TMS or TES) over the motor cortex and magnetic stimulation at the foramen magnum level.
Air stimuli applied to the toe tip facilitated magnetically evoked MEPs of mainly the muscle attached to that toe, although a less prominent facilitation was also noted in muscles attached to the adjacent toes. Neither responses evoked by TES, nor those by stimulation at the foramen magnum level, were affected by air stimuli. These results suggest that the observed facilitatory effect occurs at the cortical level.
A fairly well-organized input-output relation is present also in the foot motor area in humans, although the facilitatory effect is not so topographically restricted as is noted for the hand motor area.
Clinical Neurophysiology 08/1999; 110(7):1315-20. · 3.41 Impact Factor
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ABSTRACT: The 60-year-old women who complicated by multiple sclerosis was referred to our hospital under diagnosis of mitral valve stenosis and tricuspid valve regurgitation. The mitral valve replacement and the tricuspid valve annuloplasty were performed under cardiopulmonary bypass. In the state of multiple sclerosis, even an operation by general anesthesia could become a cause of abrupt change, but by appropriate management during and after surgery, the post operative course was uneventful without any complications, and the patient discharged on the 35th post operative day.
Kyobu geka. The Japanese journal of thoracic surgery 08/1999; 52(7):569-72.
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ABSTRACT: Intracortical inhibition of the motor cortex was investigated using a paired pulse magnetic stimulation method in 14 patients with chorea caused by various aetiologies (six patients with Huntington's disease, one with chorea acanthocytosis, a patient with systemic lupus erythematosus with a vascular lesion in the caudate, three with senile chorea and three with chorea of unknown aetiology). The time course and amount of inhibition was the same in the patients as in normal subjects, suggesting that the inhibitory mechanisms of the motor cortex studied with this method are intact in chorea. This is in striking contrast with the abnormal inhibition seen in patients with Parkinson's disease or focal hand dystonia, or those with a lesion in the putamen or globus pallidus. It is concluded that the pathophysiological mechanisms responsible for chorea are different from those producing other involuntary movements.
Journal of Neurology Neurosurgery & Psychiatry 07/1999; 66(6):783-6. · 4.76 Impact Factor
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H Mochizuki,
Y Ugawa,
K Machii,
Y Terao,
R Hanajima,
T Furubayashi, H Uesugi,
Y Shiio,
H Enomoto,
K Kamakura,
I Kanazawa
Electroencephalography and clinical neurophysiology. Supplement 02/1999; 49:90-4.
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ABSTRACT: A high-frequency oscillation in the range of 600-900 Hz has been shown to be a component of the somatosensory evoked potential (SEP) in humans. In the present communication, we studied these oscillation potentials in two neurological disorders.
Subjects were 20 healthy volunteers, 17 patients with Parkinson's disease (PD) and 3 with myoclonus epilepsy (ME). Median nerve SEPs were recorded using filters set at 0.5 and 3000 Hz. Several peaks of oscillation were obtained by digitally filtering raw SEPs from 500 to 1000 Hz, and their amplitudes and onset latencies were measured.
In normal subjects, several oscillation potentials were observed at the latency of 0 to 8 ms after the onset of N20. In PD patients, the oscillation potentials at normal latencies were significantly larger than those of normal subjects. Moreover, in 7 of 17 PD patients, they were extremely enlarged (>mean +/- 3 SD of normal values). In contrast, in patients with ME, abnormally enlarged oscillation potentials were seen at longer latencies (7-14 ms) in spite of normal-sized early oscillation potentials. Magnetoencephalographic analyses showed that any oscillation potentials originated from the primary sensory cortex.
There are at least two mechanisms for producing the oscillation potentials of SEP. Those around N20 have some relation with the basal ganglia function and are enlarged in PD patients, the others around P25-N33 are enhanced in ME patients.
Clinical Neurophysiology 02/1999; 110(1):185-91. · 3.41 Impact Factor
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ABSTRACT: To investigate whether the cortico-cortical inhibition originally reported for the human hand motor area is present in the motor cortex for sternocleidomastoid muscle (SCM) and to evaluate the amount of inhibition in spasmodic torticollis and essential tremor.
Subjects were 14 normal healthy volunteers, 10 patients with spasmodic torticollis and 5 with essential tremor involving neck muscles. A paired-pulse magnetic stimulation was performed for the SCMs and first dorsal interosseous muscles (FDIs).
In normal subjects, a subthreshold magnetic conditioning stimulus suppressed responses to a suprathreshold magnetic test stimulus when their interval was 1-5 ms in SCM. This indicates that the similar cortico-cortical inhibitory mechanism is present in the motor cortex for SCM as in the hand motor area. In the patients with spasmodic torticollis, the cortico-cortical inhibitory effect was reduced or absent in SCM, but normal in the FDI. In contrast, in patients with essential tremor, normal cortico-cortical inhibition was seen in both the SCM and FDI.
The cortico-cortical inhibitory mechanisms of the motor cortex for SCM can be studied by a paired-pulse magnetic stimulation method. Our result of reduced cortico-cortical inhibition in torticollis patients suggests abnormal excitability (hyperexcitable or disinhibited) of the motor cortex for SCM in spasmodic torticollis.
Electroencephalography and Clinical Neurophysiology 11/1998; 109(5):391-6.
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ABSTRACT: The relationships between imaging, pathology and presumed causes in surgical cases of temporal lobe epilepsy (TLE) was studied. The subject was 62 patients (33 males and 29 females) who had had no attacks for more than one year after surgery. Average age at surgery was 28.2 +/- 9.9 years. Obvious neurological abnormalities were not found in these cases. MRI, PET and SPECT were performed. Hematoxylin and eosin was used for pathological judgement. Their medical charts were used to investigate their clinical factors. Although patients suspected of having encephalitis/meningitis had been hospitalized for 2 days to three months during childhood due to disturbance of consciousness with high fever and convulsion for several days; they were not diagnosed with encephalitis/meningitis at that time, and they suffered almost no handicaps other than epilepsy for several years following their comatose episodes. [Result] (1) On MRI, mesial temporal sclerosis (MTS) was detected in 48 of 52 patients (92%); 32 (62%) had high-signal intensity on T 2-weighted images; 31 (60%) had atrophy ¿23 (44%) had high-signal intensity on T 2 + atrophy¿; 5 (10%) had calcified lesions; and 2 (4%) had cystic lesions. On PET and SPECT, abnormal cerebral blood flow was noted in 33 of 36 (92%). (2) On pathological findings (61 cases), Ammon's horn sclerosis (AHS), tumors, gliosis in lateral temporal and meningeal inflammatory finding were detected in 42 (69%), 10 (23%) and 8 (13%) cases, respectively, whereas 2 showed no abnormalities. The 2 patients with normal pathology showed both high-signal intensity and atrophy on MRI. (3) The presumed causes of TLE were encephalitis/meningitis and/or suspected of these diseases in 15 patients (24%), injuries at birth in 5 (8%), and none in 42 (68%). The presumed causes in the 43 patients with AHS were encephalitis/meningitis in 11, injuries at birth in 3, and none in 29. Of the 15 patients in whom encephalitis/meningitis was estimated as the causes of TLE, only 6 (40%) had pathological evidence of meningeal inflammatory finding. Of the 42 patients in whom cause could not be determined, 2 had pathological evidence of meningeal inflammatory finding.
Nō to shinkei = Brain and nerve 04/1998; 50(3):253-7.
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ABSTRACT: The Terumo Capiox centrifugal pump system possesses an automatic priming function in which the motor repeatedly stops and runs intermittently to eliminate air bubbles in the circuit through the micropores of the hollow-fiber membrane oxygenator. By modifying this mechanism, we have developed a pulsatile flow mode. In this mode, maximum and minimum pump rotational speeds can be independently set every 20 rpm in the range of 0 to 3,000 rpm. The duration of the pump run at maximum and minimum speeds can also be independently set every 0.1 s in the range of 0.2 to 15 s. In a clinical trial, after obtaining the desired flow rate, 2.4 L/min/m2 in nonpulsatile flow mode, a pulsatile flow mode of 60 cycles/min (with 1 cycle being maximum speed for 0.4 s and minimum speed for 0.6 s) was obtained by adding and subtracting 500 rpm to and from the rotational speed in nonpulsatile flow mode. Pulse pressures in the femoral artery and in the circuit just proximal to the perfusion cannula (6.5 mm Sarns high flow cannula with metal tip) were measured in 5 patients who underwent pulsatile cardiopulmonary bypass (CPB) for a coronary artery bypass graft (CABG), and compared to pulse pressures obtained by intraaortic balloon pumping (IABP) in 3 patients and by the pulsatile mode of the 3M Delphin pump in 3 patients. The platelet count, free hemoglobin, and beta-thromboglobulin (beta-TG) were measured and compared with measurements from another 5 patients who underwent nonpulsatile CPB. Although the pulse pressure measured in the circuit was 180 mm Hg on average, the pressure in the femoral artery was only 15 to 40 mm Hg with a mean of 20 mm Hg. In the same patients, 60 to 80 mm Hg pulse pressure was obtained with IABP. The pulse pressure obtained with the Delphin pump was not more than that obtained with the Terumo pump. There were no significant differences in percents of preoperative levels of platelet counts (pulsatile, 87.6 +/- 15.8% and nonpulsatile, 72.4 +/- 40.6%), free hemoglobin (pulsatile, 18 +/- 8 mg/dl and nonpulsatile, 25 = 7 mg/dl), and beta-TG (pulsatile 298 +/- 28 ng/ml and nonpulsatile, 312 +/- 143 ng/ml). In conclusion, although the pulsatile mode of the Terumo centrifugal pump did not exhibit any adverse effects hematologically, the pulse pressure obtained was unsatisfactorily small, mainly because of dumping caused by the perfusion cannula.
Artificial Organs 08/1997; 21(7):816-21. · 2.00 Impact Factor
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ABSTRACT: A 48-year-old man, who had a cerebral arterial aneurysm, was admitted in our institution for operation of aortic valve stenosis. At first, he underwent clipping for cerebral arterial aneurysm under precise management of his hemodynamic condition. After the clipping operation, we performed aortic valve replacement with the Toronto stentless porcine valve because no anticoagulant therapy was ideal for patient with cerebrovascular disease and larger effective orifice area was preferable for stenotic aortic annulus. By means of echocardiography, mean pressure gradient of the aoric valve decreased from 42 mmHg to 22 mmHg after the valve operation. He was discharged from the hospital on the 23rd postoperative day, and he has been doing well without thromboembolic events and bleeding complications for five postoperative months. This experience suggest that the Toronto stentless porcine valve might be one of the valve of choice for patients with aortic valve disease and cerebrovascular disease.
Kyobu geka. The Japanese journal of thoracic surgery 08/1997; 50(7):565-8.
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ABSTRACT: The usefulness of noninvasive regional cerebral blood flow measurements using Tc-99m hexamethylpropylene amine oxime (HMPAO) was evaluated in 45 patients with interictal temporal lobe epilepsy. Seizure frequency did not show any influence on flow values or side-to-side asymmetry. Patients taking phenytoin had a significantly lower mean cerebral blood flow (mean 9.5%) and lower mean cerebellar blood flow (mean 12.9%) than those not taking it. Moreover, phenytoin reduced regional cerebral blood flow in the temporal regions more prominently on the contralateral side of the epileptic focus than on the ipsilateral side. Positive MRI findings of hippocampal sclerosis along with visually detected temporal hypoperfusion on SPECT showed a lower regional cerebral blood flow and greater flow asymmetry than other imaging findings in the temporal region. Results suggest that noninvasive cerebral blood flow measurements using Tc-99m HMPAO may give useful information about interictal cerebral blood flow around an epileptic focus and about the effects of antiepileptic drugs on brain function in temporal lobe epilepsy.
Clinical Nuclear Medicine 12/1996; 21(11):867-72. · 3.67 Impact Factor
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ABSTRACT: We report a patient with primary progressive aphasia who first presented with amnesic aphasia that developed over the course of 3 years into nonfluent aphasia with buccofacial apraxia, followed in the next year by cognitive impairment and parkinsonism. Pathological findings were typical for corticobasal degeneration except for the distribution of cortical atrophy. This case suggests that corticobasal degeneration should be included in the differential diagnosis of primary progressive aphasia, especially in association with parkinsonism.
European Neurology 02/1996; 36(3):134-7. · 1.81 Impact Factor
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ABSTRACT: A 65-year-old male was referred to our institution under diagnosis of aortic dissection which passed 1 month after the onset. An aortography revealed DeBakey type I aortic dissection with the left renal artery involvement and the very narrow true lumen of the abdominal aorta compressed by the pseudolumen, especially at the orifice of the right renal artery. On the 3rd day of admission, the patient manifested SVC syndrome, oliglia and pulselessness of the femoral artery bilaterally, that indicated ischemia of the kidney and the lower extremities. An emergency operation was performed, and the ascending aorta was replaced using open distal anastomotic technique for the distal site of the aorta under deep hypothermia and retrograde cerebral perfusion method. The ischemic symptoms and SVC syndrome were disappeared promptly after operation. Postoperative CTscan showed the narrow true lumen of the abdominal aorta expanded remarkably. The postoperative course was uneventful and the patient discharged on the 54th postoperative day.
Kyobu geka. The Japanese journal of thoracic surgery 09/1995; 48(9):792-5.
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Clinical Nuclear Medicine 07/1995; 20(6):559-60. · 3.67 Impact Factor
