Publications by authors named "Shin-ichiro Osawa"

Article Synopsis
  • Recurring utterances (RUs) are a language symptom seen in severe aphasia, particularly in global or Broca's aphasia, but their underlying neural mechanisms are not well understood.
  • A novel technique called the super-selective Wada test (ssWada) was used on a 49-year-old man with drug-resistant epilepsy, targeting specific brain regions to induce Broca's aphasia with RUs through localized anesthetic administration.
  • This case highlights that RUs can occur without affecting the posterior language area or basal ganglia, suggesting ssWada's value in exploring brain-function connections related to language and cognition.
View Article and Find Full Text PDF

Background: Parkinsonism has been reported in patients with obstructive hydrocephalus (OH) following ventriculoperitoneal shunting (VPS). While levodopa works well, some cases are drug resistant. A few case series have reported that endoscopic third ventriculostomy (ETV) is beneficial, though its mechanism remains unclear.

View Article and Find Full Text PDF

Background And Objectives: The influence of the age at which complete corpus callosotomy (CC) surgery is performed on seizure outcomes remains unclear. This study aimed to evaluate the age-dependent aspects of long-term seizure outcomes after complete CC.

Methods: We reviewed 41 patients who underwent one-stage complete CC.

View Article and Find Full Text PDF
Article Synopsis
  • Providing patients with information about potential postoperative neurological deficits can help align their expectations with those of medical professionals.
  • The study involved 28 patients with drug-resistant epilepsy, where propofol was infused into specific intracranial arteries to evaluate neurological symptoms while patients remained awake.
  • The results showed that most patients retained wakefulness during the procedure, with varying degrees of neurological symptoms reported, highlighting the importance of the infusion site in determining the type of symptoms experienced.
View Article and Find Full Text PDF

Herein, we present the case of a 21-year-old man with a history of generalized tonic seizures since the age of 4 years. These seizures occurred either spontaneously or could be provoked by auditory stimuli such as the sounds of a vacuum cleaner or an electric shaver. Despite trials with 10 different anti-seizure medications, his seizures remained refractory.

View Article and Find Full Text PDF

Objective: To investigate the prevalence and intensity of grasp reflexes and to examine changes in these reflexes after shunt surgery in patients with idiopathic normal pressure hydrocephalus (iNPH).

Methods: We enrolled 147 patients with probable iNPH. A standard procedure was used to determine the presence of grasp reflexes, and the intensity of these reflexes was assessed using a four-category classification.

View Article and Find Full Text PDF

Background: Distant recurrence can occur by infiltration along white matter tracts or dissemination through the cerebrospinal fluid (CSF). This study aimed to clarify the clinical features and mechanisms of recurrence in the dentate nucleus (DN) in patients with supratentorial gliomas. Based on the review of our patients, we verified the hypothesis that distant DN recurrence from a supratentorial lesion occurs through the dentato-rubro-thalamo-cortical (DRTC) pathway.

View Article and Find Full Text PDF
Article Synopsis
  • - The study evaluates the super-selective Wada test (ssWada) as a safer and more effective alternative to the classical Wada test (cWada) for assessing language dominance in patients with epilepsy, as cWada has significant adverse effects in 10-30% of cases.
  • - Data from 17 patients revealed that ssWada identified language dominance accurately, showing 12 left, 3 right, and 2 bilateral cases, while adverse effects were much lower than those seen with cWada.
  • - The ssWada demonstrated a high accuracy rate of over 90% in determining language dominance with minimal side effects, making it a promising tool for assessing patients’ language facilities.
View Article and Find Full Text PDF

Objectives: To clarify the interhemispheric asymmetrical change in gray matter volume (GMV) in unilateral hippocampal sclerosis (HS), we compared changes in GMV relative to normal subjects between the HS and contralateral or non-HS sides.

Material And Methods: Forty-five patients with unilateral HS and 30 healthy subjects were enrolled. We quantified changes in GMV in the patients with HS as compared to GMV in the normal subjects by introducing the Z-score (Z-GMV) in each region or region of interest in unilateral HS.

View Article and Find Full Text PDF
Article Synopsis
  • Atypical localization of language function can lead to unexpected post-surgery deficits, making it hard to predict risks during presurgical evaluations.
  • The case study discusses a 32-year-old woman with drug-resistant epilepsy and highlights how a specialized technique using propofol infusion helped identify different language functions in both brain hemispheres.
  • The findings underscore the importance of understanding the relationship between vascular and functional anatomy for better presurgical assessments and tailored surgical planning.
View Article and Find Full Text PDF

Objective: To clarify whether preoperative language magnetoencephalography (MEG) predicts postoperative verbal memory (VM) changes in left mesial temporal lobe epilepsy (LMTLE).

Methods: We reviewed 18 right-handed patients with LMTLE who underwent anterior temporal lobectomy or selective amygdala hippocampectomy, 12 with (HS+) and 6 without hippocampal sclerosis (HS-). Patients underwent neuropsychological assessment before and after surgery.

View Article and Find Full Text PDF

Effective treatments for stroke after the acute phase remain elusive. Muse cells are endogenous, pluripotent, immune-privileged stem cells capable of selectively homing to damaged tissue after intravenous injection and replacing damaged/lost cells via differentiation. This randomized, double-blind, placebo-controlled trial enrolled ischemic stroke patients with modified Rankin Scale (mRS) ≥3.

View Article and Find Full Text PDF

Purpose: The anatomical association between the lesion and the perforating arteries supplying the pyramidal tract in insulo-opercular glioma resection should be evaluated. This study reported a novel method combining the intra-arterial administration of contrast medium and ultrahigh-resolution computed tomography angiography (UHR-IA-CTA) for visualizing the lenticulostriate arteries (LSAs), long insular arteries (LIAs), and long medullary arteries (LMAs) that supply the pyramidal tract in two patients with insulo-opercular glioma.

Methods: This method was performed by introducing a catheter to the cervical segment of the internal carotid artery.

View Article and Find Full Text PDF

The "odyssey plot" was used to visualize referral delays in epilepsy surgery. Participants were 36 patients (19 males; 13-67 years, median 27 years) with mesial temporal lobe epilepsy with hippocampal sclerosis (HS) who underwent resection surgery. The "referral odyssey plot" included five clinical episodes: seizure onset (T1), first visits to a non-epileptologist (T2) and to an epileptologist (T3), first admission to our epilepsy monitoring unit (EMU) (T4), and resection surgery (T5).

View Article and Find Full Text PDF

The medial side of the operculum is invisible from the lateral surface of cerebral cortex, and its functions remain largely unexplored using direct evidence. Non-invasive and invasive studies have proved functions on peri-sylvian area including the inferior frontal gyrus (IFG) and superior temporal gyrus within the language-dominant hemisphere for semantic processing during verbal communication. However, within the non-dominant hemisphere, there was less evidence of its functions except for pitch or prosody processing.

View Article and Find Full Text PDF

Disturbance of smell is often accompanied with common neurodegenerative diseases such as Parkinson's and Alzheimer's diseases. In addition, patients with head trauma, intracranial tumors, and hydrocephalus can also develop olfactory dysfunction, and some of which can improve with treatment of the underlying disease. In clinical practice, few patients complain of smell disturbances, thus olfactory dysfunction is often overshadowed by visible motor symptoms.

View Article and Find Full Text PDF

Objective: To investigate whether the slowing of bilateral postictal scalp electroencephalography (EEG) after focal impaired awareness seizures is associated with poor seizure outcomes after temporal lobe epilepsy (TLE) surgery.

Methods: This retrospective cohort study was conducted in the Department of Epileptology, Tohoku University Hospital from 2010 to 2020. The study included 42 patients with TLE who underwent a detailed presurgical evaluation and sequential resective surgery for the unilateral probable epileptogenic temporal lobe with 1 year or more of follow-up.

View Article and Find Full Text PDF

An intrinsically soft organic electrode consisting of poly(3,4-ethylenedioxythiophene)-modified polyurethane (PEDOT-PU) is embedded into a bilayer film of polyvinyl alcohol (PVA) hydrogels for developing a self-closing cuff electrode for neuromodulation. The curled form of the PVA hydrogel is prepared by releasing internal stress in the bilayer structure. The inner diameter of the cuff electrode is set to less than 2 mm for immobilization to the vagus nerve (VN) of humans and pigs.

View Article and Find Full Text PDF

The Wada test is the gold standard for determining language-dominant hemisphere. However, the precise determination of language areas in each patient requires more invasive methods, such as electrocortical stimulation. Some studies have reported the use of anesthetic injection into selective cerebral arteries to predict postoperative function.

View Article and Find Full Text PDF

Background: Hemifacial spasm (HFS) is caused by neurovascular contact along the facial nerve's root exit zone (REZ). The authors report a rare HFS case that was associated with ipsilateral subclavian steal syndrome (SSS).

Observations: A 42-year-old man with right-sided aortic arch presented with progressing left HFS, which was associated with ipsilateral SSS due to severe stenosis of the left brachiocephalic trunk.

View Article and Find Full Text PDF

Objective: We developed an actuator-driven pulsed water jet (ADPJ) device to achieve maximal lesion dissection with minimal risk of normal structural damage. Despite the unique dissection characteristics, there is a risk of dissemination of tissue dispersion; however, there is no established method to quantify the dispersion. Hence, this study aimed to assess the factors associated with dispersion and propose a simple experimental method using spectrophotometry to evaluate the degree of dispersion in a wet field.

View Article and Find Full Text PDF

Background: Recovery time after corpus callosotomy (CC) is known to be longer in elderly than in younger patients.

Objective: To evaluate the relationship between patient age and recovery time of activities of daily living (ADL) after 1-stage complete CC.

Methods: This study included 41 patients (22 women; aged 13 months-34 years, median 7 years) who underwent 1-stage complete CC for medically intractable seizures with drop attacks, infantile spasms, and/or bilaterally synchronized electroencephalographic discharges between August 2009 and April 2019.

View Article and Find Full Text PDF