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ABSTRACT: The case of a 40-year-old man with a clival chordoma who presented with symptoms of pathological laughter and left sixth cranial nerve paresis is reported. Laughing and talking during sleep were noted on polygraphic and videotape recordings of nocturnal sleep. Selective disorganization of sleep was observed, with laughing facial expressions and a lack of muscular atonia. The tumor developed in the prepontine cistern, compressing the pontomesencephalic structures backward and involving the upper clivus and the left cavernous sinus. No recurrence of laughter attacks were noted after total removal of the tumor. The sleep patterns observed were similar to those of experimental animals with lesions of the peri-alpha locus ceruleus. The importance of uncontrolled laughter as a sign of a ventral brain-stem mass is emphasized.
Journal of Neurosurgery 10/1993; 79(3):428-33. · 2.96 Impact Factor
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ABSTRACT: Hyperbaric chamber dives at 19 ATA with helium-oxygen were performed at the Japan Marine Science Technology Center, Yokosuka, from January 31 to February 2 in 1990. During simulated underwater experiments, event-related potentials were recorded in 2 divers for assessment of the cognitive function. Although the P300 amplitude of the potentials did not show any significant change, its latency was clearly prolongated and this prolongation continued to when the decompression reached to 70 m below sea level. These findings indicated that the hyperbaric environment corresponding to 180 m below sea level or less must cause some cognitive dysfunctions and that P300 is useful for early detection of those dysfunctions or HPNS.
Journal of UOEH 07/1991; 13(2):143-8.
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ABSTRACT: A case of arteriovenous malformation (AVM) associated with a meningioma is reported. A 28-year-old woman was hospitalized for generalized convulsion. CT scan and right carotid angiogram revealed AVM in the right parietal lobe extending to the wall of the lateral ventricle. At the time of surgery an intraventricular meningioma attached to the choroid plexus was found in the excised cavity of the AVM. It is suggested that the meningioma might have been caused by chronic irritation due to an increased blood flow in the arteries supplying the AVM, because the AVM and the meningioma exist in the same lesion and share the same blood supply.
Journal of UOEH 04/1991; 13(1):35-8.
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ABSTRACT: A clinical lesion study and intraoperative epidural recordings were made to test the origin and clinical significance of the spinal N13 and P13 of somatosensory evoked potentials (SEP) that follow median nerve stimulation. Intraoperatively, the respective peak latencies of spinal P13 and N13 coincided with those of the N1 component of the dorsal cord potential and its phase reversed positivity. On both the ventral and dorsal sides of the cervical epidural space, maximal amplitude was at the C5 vertebral level to which nerve input from the C6 dermatome is the main contributor. The modality of sensory impairment in the hand dermatome was examined in selected patients with cervical lesions, who showed such normal conventional SEP components as Erb N9, far-field P9, P11, P14, N18 and cortical N20, with or without loss of spinal N13. Statistically, the loss of spinal N13 was associated with decrease of pain sensation in the C6 dermatome. This was interpreted as being due to damage to the central grey matter of the cord, including the dorsal horn. Our results suggest the spinal N13 and P13 originate from the same source in the C6 spinal cord segment and that they are good indicators for the detection of centromedullary cervical cord damage.
Journal of Neurology 12/1990; 237(7):410-5. · 3.47 Impact Factor
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ABSTRACT: Ten patients with cerebral venous angioma (VA) were followed up for 12 to 106 months. Seven VAs were found as a result of intracerebral hemorrhage and the others were found incidentally. Among three VAs cauterized or partially excised, one disappeared but two were unchanged on follow-up angiography. Another VA, treated by irradiation following evacuation of the hematoma, gradually reduced in size on angiography. In the remaining six VAs treated conservatively, follow-up angiography demonstrated no visible change. During the follow-up period, bleeding from VA was encountered in one patient who had previously suffered from intracerebral hemorrhage. Prevention of bleeding from VA is considered important; however, complete extirpation of VA is difficult since the resectable area of normal brain parenchyma including the VA is very limited. From our experience, radiation therapy is believed to be useful when VA is considered to carry the risk of hemorrhage.
Neurologia medico-chirurgica 09/1990; 30(8):599-603. · 0.61 Impact Factor
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ABSTRACT: Simultaneous overnight recordings of intracranial pressure (ICP) and electroencephalography (EEG) were conducted on 85 neurosurgical patients with intracranial hypertension and/or ventriculomegaly. Intracranial pressure waves were classified into five types according to the pattern of appearance, and their correlation with sleep cycles and clinical conditions of patients were investigated. A-waves appeared exclusively in patients with long-standing intracranial hypertension, and episodic B-waves appeared in patients with chronic hydrocephalus or a postoperative tumor-free condition. When these episodic pressure waves appeared, the patients were conscious and sleep cycles including REM stage were observed. Persistent, high pressure B-waves were seen mostly in patients with an acute phase of intracranial hemorrhages. The consciousness of these patients ranged from drowsy to stupor. EEG showed alternate appearances of light sleep and waking rhythms in accordance with cyclic oscillations of B-waves which coincided with periodic, apneic respiratory rhythms. When markedly regular B-waves of moderately high pressure appeared continuously, the patients were severely impaired in consciousness and were mainly in a subacute phase of intracranial hemorrhages. EEG showed continuous slow activities and sleep stages were not scored in these patients. No characteristic clinical features were found in patients whose ICP remained within normal range without pressure waves throughout the recording.
Journal of UOEH 01/1990; 11(4):371-81.
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ABSTRACT: Changes in intracranial pressure (ICP) during sleep were investigated in 37 patients with chronic intracranial hypertension or chronic hydrocephalus, in whom episodic pressure waves characterized by A-waves or episodic B-waves were seen in Part I of this paper. The patients were conscious, and sleep stages including REM sleep were observed in all of them. During non-REM sleep, ICP significantly rose in Stage II on many occasions, and was always lower in Stage IV than in other sleep stages. A marked elevation of ICP was seen in REM sleep. ICP changes during REM sleep were characterized by frequent appearances of the pressure waves; 88.9% of A-waves and 95.1% of episodic B-waves appeared during REM sleep. The initiation of REM sleep scored on EEG began 1 to 2 minutes prior to or at the onset of the episodic pressure waves. The episodic pressure waves are assumed to be induced by the intracranial conditions in REM sleep, when increased brain activity and reduced sympathetic tone are known to occur simultaneously.
Journal of UOEH 01/1990; 11(4):383-91.
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ABSTRACT: Hyperbaric chamber dives at 19 ATA with helium-oxygen were performed at the Japan Marine Science Technology Center from November 15 to December 3 in 1988 and from January 25 to February 4 in 1989. During simulated underwater experiments, auditory middle latency responses (MLRs) and short latency somatosensory evoked potentials (SSEPs) were recorded in 3 professional divers (2 divers in each dive) for assessment of brain function. During the saturation dive (180 m below sea level) component Pa on MLR was lost, while component Po remarkably increased in amplitude. These MLR changes rapidly recovered between the beginning of decompression and at about 90 m below sea level. On the other hand, N9-N20 interpeak latency on SSEP slightly or moderately increased in the both divers, but N9-N14 interpeak latency was not affected by the 19 ATA saturation dive. These results suggest that the hyperbaric environment corresponding to 180 m below sea level cause some cerebral dysfunctions, probably between the brainstem and the cortex, but these dysfunctions are only transient.
Journal of UOEH 01/1990; 11(4):441-7.
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ABSTRACT: A case of asymptomatic syringomyelia associated with tentorial meningioma is reported. A 53-year-old female was admitted to our hospital with the complaints of headache, decrease of bilateral visual acuity and gait disturbance. Neurological examination revealed no abnormality except for bilateral papilledema and left cerebellar sign. Motor and sensory systems were also intact. CT and MRI scans showed a left tentorial mass lesion, cervical syringomyelia and left tonsillar herniation. A relationship between the fourth ventricle and syringomyelia was not clearly identified. The tumor was totally removed and a histological diagnosis of fibroblastic meningioma was made. Postoperative radiological examination showed a diminishing of syringomyelia with the improved tonsillar herniation. Association of syringomyelia with brain tumor was reviewed, and its pathogenesis was discussed.
No shinkei geka. Neurological surgery 11/1989; 17(10):985-9. · 0.13 Impact Factor
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ABSTRACT: A false aneurysm that developed at the nidus of the cerebellar AVM in a 5-year-old boy is reported. A review of previous reports indicated that non-traumatic false aneurysms occur exclusively in the intraparenchymal brain tissue in association with vascular anomalies. Because the development of a false aneurysm at the nidus of AVM is extremely rare, its possible pathogenesis is discussed.
Journal of UOEH 10/1989; 11(3):333-40.
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ABSTRACT: The authors describe the case of a 37-year-old female with a symptomatic epithelial cyst in the cerebellopontine angle, which is extremely rare. The cyst caused trigeminal neuralgia, which completely disappeared following its removal. The histological diagnosis was choroidal epithelial fluid-filled cyst. The wall of the cyst consisted of a single layer of epithelial cells with microvilli and a basement membrane.
Neurologia medico-chirurgica 06/1989; 29(5):424-8. · 0.61 Impact Factor
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ABSTRACT: A rare case of thrombosed AVM presenting temporal lobe epilepsy is reported. A 27-year old man was admitted to our hospital because of a 7-year history of temporal lobe epilepsy. He had also suffered from generalized seizure since he was 6 years old. No neurological deficit was disclosed. CT scan demonstrated a small calcified mass lesion in the left temporal lobe which was not enhanced by contrast study. Skull X - P and cerebral angiography were normal. Low intensity area on T1-weighted MR image corresponded to the high density area on CT scan. T2-weighted MR image demonstrated that peripheral low intensity area was more prominent and extensive. Conventional EEG showed focal spike discharges from the left fronto-central lead, and subdural EEG recordings showed intermittent spike discharges from the medial side of the left temporal lobe. A 5 cm temporal lobectomy was performed and a thick fibrous mass adjacent to the hippocampoamygdala complex was removed. Histopathological examination demonstrated a thrombosed AVM surrounded by gliotic neural tissue.
No shinkei geka. Neurological surgery 05/1989; 17(4):369-73. · 0.13 Impact Factor
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ABSTRACT: Hyperbaric chamber dives at various equivalent depths below sea level, i.e. 7, 14, 19 and 31 atmosphere absolute (ATA) with helium-oxygen or helium-nitrogen-oxygen have been performed at the Japan Marine Science and Technology Center. A two-dimensional (topographic) display of the scalp EEG was used during simulated underwater experiments to determine; 1) Whether there are any characteristic EEG patterns in high pressure nervous syndrome (HPNS), 2) the relationship between the EEG changes and the compression rate, and 3) the relationship between the EEG changes and the characteristic signs and symptoms of HPNS. A two-way analysis of variance and a distribution analysis technique revealed that the topographic brain patterns depended on the diving depth and indicated the most affected brain areas during compression and decompression. Significant correlations between the diving depth and the EEG potentials were observed at different brain locations. Alpha waves showed a diffuse cortical distribution. Theta wave activity was more localized in the frontal midline region. These waves developed paroxysmally in relatively brief bursts supplanting or intermixing with normal background EEG rhythms. In our subjects, frontal midline theta activity was associated mostly with some of the characteristic features of HPNS, such as a transient episode of laughter or euphoria at depths greater than 21 ATA. An intimate correlation between frontal midline theta wave and laughter was observed. Frontal midline theta waves may be related to emotional activities induced by helium under high pressure. There were significant individual variations in susceptibility and subjective signs and symptoms. The EEG is of great value in studying man's physiological reactions in an undersea environment and also very important in selecting divers who are relatively more tolerant of a severe hyperbaric environment.
Journal of UOEH 10/1988; 10(3):247-61.
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ABSTRACT: Hyperbaric chamber dives at 31 ATA with helium-oxygen were performed at the Japan Marine Science and Technology Center in 1987. During simulated underwater experiments, auditory brain stem responses were recorded in 4 professional divers for assessment of brain stem function. All divers had no clinical symptoms at 150 m below sea level, and their ABRs also showed no significant changes. During the 150-250 m depth saturation dives, all divers complained of various symptoms such as euphoria, ataxia, joint pain, tremor and dyspnea, while, I-III and I-V interpeak latencies on their ABRs increased with a tendency of recovery. Furthermore, the changes of both interpeak latency were independent of each other. These results indicate that transient dysfunction clinically or subclinically occurred at the processes between 150-300 m below sea level. Moreover, independent changes of I-III and I-V interpeak latencies in this study may mean that the pathways reached to the generation sites of wave III and V were different.
Journal of UOEH 10/1988; 10(3):317-24.
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Neurologia medico-chirurgica 07/1988; 28(6):546-52. · 0.61 Impact Factor
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ABSTRACT: The present study was carried out on animals and humans in order to clarify auditory dominancy or lateralization and the contribution site of auditory evoked middle latency responses (AEMLRs). Normal AEMLRs on guinea pigs and humans were quite similar and consisted of two negative and two positive peaks between 8 and 50 msec following the start of an auditory stimulus. In normal human subjects, the component Pa (peak to baseline measurement) or Na-Pa (trough to peak measurement) was significantly greater in the temporal area contralateral to the stimulated ear than in the ipsilateral temporal area. In guinea pigs, however, AEMLRs were attenuated only by stimulation contralateral to the side, on which a lesion was made by unilateral aspiration of the lemniscus or the inferior colliculus. This auditory lateralization and contralateral dominancy were also verified by the direct cortical recording of AEMLRs in humans and also by analysis of auditory evoked brain mapping. In clinical studies, AEMLRs have been obtained even in a premature infant born after a 44-week pregnancy. In patients with well localized lesions of the brain stem, all components of the AEMLR to stimulation contralateral to the lesion side were affected. However, component Pa of the response to stimulation contralateral to the lesion was mainly abolished in patients with unilateral thalamic or temporal lesions. The following results were obtained: 1) component Pa (or Na-Pa) of AEMLR has significant lateralization, 2) the generation site of Pa may be in the subcortical thalamic projection of the contralateral lobe, 3) component Po (or No-Po) is a true neurogenic response but is frequently enhanced by the post-auricular reflex, 4) the contralateral inferior colliculus is very important for the generation of Po, 5) the auditory system (hearing) may have contralateral AEMLR dominancy.
Journal of UOEH 04/1988; 10(1):11-30.
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ABSTRACT: To clarify the effects of disturbances in basilar artery blood flow, basilar artery angiospasm was induced in 2 cats and 4 guinea pigs and auditory brain-stem responses (ABRs) were continuously recorded preceding, during and following the angiospasm. The angiospasm caused specific ABR changes in that waves II (P2-N2) and III (P3-N3) were attenuated without any corresponding amplitude reduction of P4. Those changes were equivalent following stimulation of either ear. Moreover, the ABR changes gradually recovered within 5 h. On the basis of the animal experiments, 52 patients with subarachnoid hemorrhage, supratentorial tumor showing increased intracranial pressure or hydrocephalus were selected for repeated ABR examinations. ABR abnormalities similar to those observed in the animal experiment were obtained especially from the patients exhibiting grade 3 or 4 symptomatology with subarachnoid hemorrhage. In these cases, the wave III to wave IV-V amplitude ratio was significantly decreased. In some cases the ABR abnormalities and the wave III to wave IV-V amplitude ratio recovered as the clinical course improved. These results support the conclusion that specific ABR changes (wave III to wave IV-V amplitude ratio) reflect transient ischemic dysfunction of the midline portion of the brain-stem caused by disturbances of basilar artery blood flow.
Electroencephalography and Clinical Neurophysiology 03/1988; 69(2):148-59.
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ABSTRACT: In 47 cases with intracranial lesions, auditory brainstem responses (ABRS) were studied. From a detailed analysis of these data, the following results were concluded: In some cases, the intramedullary and extramedullary pontine tumor could be differentiated by ABR, A very small cerebello-pontine angle tumor was detected by ABR, ABR monitering was useful to evaluate brainstem function during the surgical operation, and ABRS were clinically very useful methods for predicting the outcome of a severe head injury and diagnosis of brain death. These results indicate that ABRS contribute to functional diagnosis of various diseases of the central nervous system.
Journal of UOEH 07/1987; 9(2):157-65.
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ABSTRACT: To identify the origin of scalp-recorded far-field negativity of short-latency somatosensory evoked potentials to median nerve stimulation (designated N18), direct records were made from the thalamus and ventricular system during 4 stereotaxic and 3 posterior fossa operations. In the thalamus a negative potential with almost the same latency as the scalp N18 was restricted to the Vim nucleus, but there was a large positive potential in the VC nucleus and medial lemniscus. Vim negativity increased in amplitude when high frequency stimulation was given to the median nerve, indicative of a facilitation effect. In contrast, the amplitude of scalp N18 decreased at high frequency stimulus. Direct recordings made through the medulla oblongata to the mid-brain showed a negative potential with gradually increasing latency. Above the upper pons, there was stationary negativity with no latency shift. The similarity between this negative potential and N18 is shown by their having the same latency and same response to the amplitude reduction and latency prolongation produced by high frequency stimulus. Our data suggest that scalp N18 comes from brain-stem activity between the upper pons and the mid-brain rather than from the thalamus.
Electroencephalography and Clinical Neurophysiology 77(1):39-51.
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ABSTRACT: We here report the first description of the intramedullary spatial distribution of evoked dorsal horn potentials in a human spinal cord. Somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded within the cervical spinal cord of a patient with syringomyelia. Spinal intramedullary recording demonstrated a negative slow wave of the same polarity as the dorsal spinal surface response and a complex wave interpreted as the summation of its negativity and phase-reversed positivity. These two wave forms may depend on the locations at which the recording electrodes are attached to the dorsal horn.
Electroencephalography and Clinical Neurophysiology 77(3):233-6.
