Tadashi Hamasaki

Bilateral pallidal stimulation for idiopathic segmental axial dystonia advanced from meige syndrome refractory to bilateral thalamotomy

Meige syndrome is an adult‐onset dystonic movement disorder that predominantly involves facial muscles, while some patients with this syndrome develop spasmodic dysphonia and dystonia of the neck, trunk, arms, and legs. We report that all dystonic symptoms that had been refractory to both pharmacotherapy and bilateral thalamotomy were markedly alleviated by bilateral pallidal stimulation in a patient with segmental axial dystonia advanced from Meige syndrome.

Lack of Reelin causes malpositioning of nigral dopaminergic neurons: Evidence from comparison of normal and Relnrl mutant mice

The reeler gene (Relnrl, formerly rl) product Reelin controls neuronal migration and positioning and thereby plays a key role in brain development. Mutation of Reln leads to widespread disruption of laminar cortical regions and ectopia in some brainstem nuclei. In the embryonic striatum of normal mice, a substantial expression of reelin mRNA has been documented; however, the anomalous positioning of neurons in the basal ganglia of reeler mice remains to be studied. We provide first evidence for a potential role of Reelin in the developmental formation of the substantia nigra. In reeler mutant mice lacking Reelin, dopaminergic neurons destined for the substantia nigra fail to migrate laterally and become anomalously clustered just lateral to the ventral tegmental area. Their axons appear to project to striatal patches forming “dopamine islands.” Results from the normal mice show that, at the midembryonic stage, Reelin identified with CR‐50 is highly concentrated in the ventral mesencephalon, where nigral dopaminergic neurons are in progress to migrate laterally to their eventual position of the adult brain. A combination of CR‐50 labeling and anterograde axonal tracing provided evidence that embryonic striatal neurons may supply the ventral portion of the mesencephalon with Reelin through their axonal projections. We hypothesize that Reelin plays a role in the positioning of nigral dopaminergic neurons and that it can act as an environmental cue at a remote site far from its birthplace via a transaxonal delivery system. J. Comp. Neurol. 461:166–173, 2003.

Neuronal cell migration for the developmental formation of the mammalian striatum

The mammalian striatum is the largest receptive component of the basal ganglia circuit. It is involved in the control of various aspects of motor, cognitive, and emotional functions. In the telencephalon, the striatum has a unique histological property totally different from the cortical area and its ontogenesis remains largely unknown. In this review, we introduce recent advances in the understanding of neuronal cell migration, one of the most critical processes in the early phase of histogenesis that occurs in the embryonic striatum. It appears that there are three major modes of neuronal cell migration in the developmental formation of the striatum. They are (radial) outward, tangential, and inward migration, supplying the striatum with projection neurons, interneurons, and early-generated transient neurons that originate in the preplate, respectively. We challenge the classical concept that the striatum is solely derived from the restricted germinal area located in the basal telencephalon by providing evidence that striatal development requires the intermixture of different types of neurons originating from distinct regions of the telencephalon.

Effect of bilateral subthalamic nucleus stimulation on levodopa-unresponsive axial symptoms in Parkinson’s disease

SummaryBackground. The levodopa responsiveness of motor, particularly axial symptoms is a good predictor of the effectiveness of subthalamic nucleus (STN) stimulation in patients with Parkinson’s disease (PD). However, many Japanese PD patients are intolerant of higher doses of antiparkinsonian drugs and some aspects of their axial symptoms may remain unresponsive to treatment. We retrospectively investigated the effects of bilateral STN stimulation on the axial signs unresponsive to levodopa in Japanese patients with PD.Methods. We enrolled 29 consecutive patients into this study. Six independent axial symptoms, i.e. falling, freezing, gait, standing, posture, and postural instability, were scored on the Unified Parkinson’s Disease Rating Scale (UPDRS), before and 3 months after bilateral STN stimulation and differences were statistically analysed.Findings. Postoperatively, the mean levodopa dosage was decreased by 27%. The preoperative responsiveness to antiparkinsonian drugs with respect to freezing, gait, posture, and postural instability were positively correlated with postoperative off-medication improvement (p < 0.05). For each individual axial symptom, some patients showed an excellent response to STN stimulation, despite preoperative unresponsiveness to levodopa. These selected patients were not always treated with lower doses of antiparkinsonian drugs preoperatively, but they had milder preoperative scores on the UPDRS with respect to daily activities and overall axial function.Conclusions. The axial symptoms of PD unresponsive to levodopa were ameliorated by bilateral STN stimulation in patients manifesting a milder degree of preoperative axial signs. Our findings suggest that STN stimulation exerted a definite but limited effect on levodopa-unresponsive axial features, pointing to the need to identify different target structures that control axial functions via non-dopaminergic systems.

Long Disease Duration Interferes With Therapeutic Effect of Globus Pallidus Internus Pallidal Stimulation in Primary Cervical Dystonia

Objectives:  We retrospectively investigated the correlation between disease duration and the therapeutic effect of globus pallidus internus (GPi) stimulation in patients with primary cervical dystonia (CD).

Apraxia of lid opening is alleviated by pallidal stimulation in a patient with Parkinson’s disease

Apraxia of lid opening (ALO) is a syndrome characterized by a non‐paralytic inability to open the eyes at will in the absence of visible contraction of the orbicularis oculi muscle. Here we report that globus pallidus internus deep brain stimulation on the right side markedly alleviates ALO as well as gait freezing in a patient with Parkinson’s disease.

Seizures as a presenting symptom in neurosurgical patients: a retrospective single-institution analysis.

BACKGROUND In patients with brain lesions, the appropriate management of epileptic seizures is important because recurrent seizures have a negative effect on the clinical course and quality of life. Acute symptomatic seizures are known to be one of the risk factors to develop epilepsy that cause recurrent unprovoked seizures in the later stage. To obtain background information, we performed a retrospective study in which we investigated the incidence of seizures as one of the presenting symptoms in neurosurgical patients admitted to our department during the past 43 years. METHODS We extracted 4537 consecutive patients from 11,675 records in our inpatient database to calculate the seizure incidence in patients with 19 most common diagnoses. We also studied whether the location of cortical lesions have relation to the seizure incidence. RESULTS Among 2342 patients with brain tumors, 9 of 18 (50%) ganglioglioma-, 40 of 87 (46%) oligodendroglioma-, 69 of 207 (33%) low-grade astrocytoma-, 172 of 804 (21%) high-grade astrocytoma- or anaplastic oligodendroglioma-, 84 of 598 (14%) meningioma-, 38 of 313 (12%) metastatic brain tumor-, 7 of 67 (10%) malignant meningioma-, 7 of 79 (9%) ependymoma-, and 11 of 169 (7%) malignant lymphoma patients suffered seizures. There were 1626 patients with vascular lesions, 20 of 80 (25%) with cavernous malformation, 61 of 281 (22%) with arteriovenous malformation, 50 of 666 (8%) with subarachnoid hemorrhage, 26 of 457 (6%) with brain infarcts, and 5 of 142 (4%) with hypertensive brain hemorrhage had seizures. Of the 569 patients with traumatic brain injury, 33 of 168 (20%) with traumatic intracranial hemorrhage, 6 of 31 (19%) with brain concussion, 18 of 96 (19%) with brain contusion, 15 of 244 (6%) with chronic subdural hematoma, and 1 of 30 (3%) with minor head injury suffered seizures. We found that these seizure incidences were significantly higher when the cortical lesion was located in the frontal lobe (p<0.01, chi square test) but not in parietal, occipital, nor temporal lobes. CONCLUSION We investigated the prevalence rate of seizures at the time of admission in a large number of patients who had been treated in our institution. Our results suggest that seizures are a common feature in patients with slow-growing and frontal intra-parenchymal lesions.

Neurotoxicity evoked by N-methyl-D-aspartate in the organotypic static slice cultures of rat cerebral cortices: Effect of GABA(A) receptor activation

Abstract We investigated the neurotoxicity evoked by N-methyl-d-aspartate (NMDA) receptor stimulation in the organotypic static slice cultures of rat cerebral cortices. We also examined whether the γ-aminobutyric acid (GABA)A receptor agonist muscimol has a protective effect on the NMDA-mediated neurotoxicity in this culture system. NMDA-mediated cytotoxicity was evaluated histologically and quantified by the measurement of lactate dehydrogenase (LDH) release into the culture medium. There was an NMDA-induced, dose-dependent leakage of LDH release and neuronal cell death, which were not attenuated by muscimol treatment. The results suggested that NMDA neurotoxicity is reproduced in the organotypic culture, and that GABAA receptor activation exerted no protective action against the NMDA cytotoxicity.

Abolition of postapoplectic hemichorea by Vo-complex thalamotomy: Long-term follow-up study

We report a patient with hemichorea following subthalamic hemorrhage. Vo‐complex thalamotomy abolished the choreic movements for over 4 years of follow‐up.

Subthalamic nucleus stimulation improves Parkinson's disease-associated camptocormia in parallel to its preoperative levodopa responsiveness

Objective The aim of this work was to identify factors predictive of postoperative improvement of camptocormia in patients with Parkinsons disease (PD) treated by subthalamic nucleus (STN) stimulation. Background Camptocormia, one of the most disabling features of PD, often responds poorly to medical therapies. The reported effects of deep brain stimulation on PD-associated camptocormia vary, and preoperative characteristics affecting the surgical outcome remain unclear. Methods We evaluated 17 patients with camptocormia whose preoperative off-medication thoracolumbar angle exceeded 45°. We used photographs to measure their thoracolumbar angle preoperatively, 3 months after surgery, and at the last follow-up (mean 36.5 months postoperatively) in status on-medication and off-medication. The patient age, duration of PD and camptocormia, daily medications, Unified Parkinsons Disease Rating Scale (UPDRS) subscores and the Schwab-England activity of daily living scale (S-E) were also recorded. Univariate analysis was performed to identify factors predictive of the postoperative improvement of camptocormia. Results STN stimulation significantly improved the UPDRS subscores and S-E, and resulted in a reduction of daily medications 3 months post-treatment. The preoperative thoracolumbar angle (mean±SD) in status off-medication (84.0±29.5°) was significantly ameliorated 3 months postoperatively (49.8±29.3°) and at the last follow-up (54.8±28.3°). There was no correlation between the postoperative camptocormia improvement rate and preoperative parameters other than the duration and severity of camptocormia and the levodopa responsiveness of the thoracolumbar angle. Symptom duration negatively affected levodopa responsiveness. Conclusions STN stimulation improves PD-associated camptocormia in parallel with preoperative levodopa responsiveness. Long symptom duration interferes with levodopa responsiveness.