Publications by authors named "Atsushi Shima"

Introduction: Magnetic resonance imaging (MRI)-determined atrophy of the nucleus basalis of Meynert (Ch4) predicts cognitive decline in Parkinson's disease (PD). However, interactions with other brain regions causing the decline remain unclear. This study aimed to describe how MRI-determined Ch4 atrophy leads to cognitive decline in patients with PD.

View Article and Find Full Text PDF

Background And Objectives: Neural computations underlying gait disorders in Parkinson disease (PD) are multifactorial and involve impaired expression of stereotactic locomotor patterns and compensatory recruitment of cognitive functions. This study aimed to clarify the network mechanisms of cognitive contribution to gait control and its breakdown in patients with PD.

Methods: Patients with PD were instructed to walk at a comfortable pace on a mat with pressure sensors.

View Article and Find Full Text PDF

Over one-third of stroke survivors develop aphasia, and language dysfunction persists for the remainder of their lives. Brain language network changes in patients with aphasia. Recently, it has been reported that phase synchrony within a low beta-band (14-19 Hz) frequency between Broca's area and the homotopic region of the right hemisphere is positively correlated with language function in patients with subacute post-stroke aphasia, suggesting that synchrony is important for language recovery.

View Article and Find Full Text PDF

Objectives: Neuropsychiatric symptom could be useful for detecting patients with prodromal dementia. Similarities and differences in the NPSs between preclinical/prodromal Alzheimer's disease (AD) and prodromal Parkinson's disease dementia (PDD)/Dementia with Lewy bodies (DLB) may exist. This study aimed to compare the NPSs between preclinical/prodromal AD and prodromal PDD/DLB.

View Article and Find Full Text PDF

Purpose: Neuromelanin-sensitive MRI (NM-MRI) has proven useful for diagnosing Parkinson's disease (PD) by showing reduced signals in the substantia nigra (SN) and locus coeruleus (LC), but requires a long scan time. The aim of this study was to assess the image quality and diagnostic performance of NM-MRI with a shortened scan time using a denoising approach with deep learning-based reconstruction (dDLR).

Materials And Methods: We enrolled 22 healthy volunteers, 22 non-PD patients and 22 patients with PD who underwent NM-MRI, and performed manual ROI-based analysis.

View Article and Find Full Text PDF

A man hospitalized for cerebral infarction developed drug-induced belly dancer syndrome, which improved after withdrawal of droxidopa and amantadine. Drugs that modulate dopamine neurotransmission have been reported to be associated with this syndrome. When belly dancer syndrome is suspected, clinicians should consider drug-induced abdominal dyskinesia and medication withdrawal.

View Article and Find Full Text PDF

We aimed to clarify whether dopamine depletion in the posterior dorsal striatum in early-stage Parkinson's disease (PD) alters synchronized activity in the cortico-basal ganglia motor circuit. In sum, 14 PD patients and 16 matched healthy controls (HC) underwent [11C]-2-β-carbomethoxy-3-β-(4-fluorophenyl) tropane positron emission tomography to identify striatal dopamine-depleted areas. The identified map was applied to functional magnetic resonance imaging (fMRI) to discover abnormalities in functional connectivity (FC) during motor-task and rest-state in PD patients in the drug-off state relative to HC.

View Article and Find Full Text PDF

Progressive supranuclear palsy (PSP) is characterized by recurrent falls caused by postural instability, and a backward gait is considered beneficial for postural instability. Furthermore, a recent approach for rehabilitation combined with gait-oriented synchronized stimulation using non-invasive transcranial patterned stimulation could be promising for balance function. Here, we present a case of PSP with backward gait training combined with gait-synchronized transcranial alternating current stimulation (tACS).

View Article and Find Full Text PDF

Most post-stroke patients have long-lasting gait disturbances that reduce their daily activities. They often show impaired hip and knee joint flexion and ankle dorsiflexion of the lower limbs during the swing phase of gait, which is controlled by the corticospinal tract from the primary motor cortex (M1). Recently, we reported that gait-synchronized closed-loop brain stimulation targeting swing phase-related activity in the affected M1 can improve gait function in post-stroke patients.

View Article and Find Full Text PDF

Neuroimaging using the 7-Tesla (7T) human magnetic resonance (MR) system is rapidly gaining popularity after being approved for clinical use in the European Union and the USA. This trend is the same for functional MR imaging (MRI). The primary advantages of 7T over lower magnetic fields are its higher signal-to-noise and contrast-to-noise ratios, which provide high-resolution acquisitions and better contrast, making it easier to detect lesions and structural changes in brain disorders.

View Article and Find Full Text PDF

Objective: The motor severity in Parkinson disease (PD) is believed to parallel dopaminergic terminal degeneration in the striatum, although the terminal was reported to be virtually absent by 4 years postdiagnosis. Meanwhile, neuromelanin-laden dopamine neuron loss in the substantia nigra (SN) elucidated a variability at early stages and gradual loss with less variability 10 years postdiagnosis. Here, we aimed to clarify the correlation between motor impairments and striatal dopaminergic terminal degeneration and nigral neuromelanin-laden dopamine neuron loss at early to advanced stages of PD.

View Article and Find Full Text PDF
Article Synopsis
  • The study aimed to showcase the effectiveness of small, insertable inductively coupled coils for MR microscopy in a 7T MRI system, focusing on brain specimens from monkeys and mice.
  • Two types of coils were constructed (D26 and D64) and tested for their signal-to-noise ratio (SNR) and parallel imaging capabilities compared to a regular knee coil.
  • Results showed that the insertable coils significantly improved SNR, provided detailed brain images, and demonstrated ease of use for advanced MR microscopy.
View Article and Find Full Text PDF
Article Synopsis
  • The study aimed to explore the outcomes and natural history of spontaneous amyloid-related imaging abnormalities (ARIA)-like cases in patients with cerebral amyloid angiopathy-related inflammation (CAA-ri).
  • It involved a multicenter, observational approach, tracking patients through systematic data collection and MRI scans at multiple follow-up points over 24 months.
  • Results showed that a significant majority of patients experienced clinical recovery by 12 months, although some were at high risk for intracerebral hemorrhage and recurrence of CAA-ri, especially if they had baseline cortical superficial siderosis.
View Article and Find Full Text PDF

This article reviews the stereotactic targets in the posterior subthalamic area(PSA), fields H1/H2 of Forel(pallidothalamic tract), and the pedunculopontine nucleus(PPN)to complement the preceding articles on stereotactic and functional neurosurgery for movement disorders in the present issue of . Two regions within the subthalamus, the PSA and fields H1/H2 of Forel, are the revisited stereotactic targets to treat movement disorders. Currently, the PSA is often utilized to treat essential tremor and various types of tremor.

View Article and Find Full Text PDF

The pathomechanisms and treatment strategy for rare presentations of reversible cerebral vasoconstriction syndrome (RCVS) with anti-phospholipid syndrome (APS) remain to be determined. We report a 67-year-old woman with APS who presented with ischemic stroke due to RCVS. She was treated with low-dose cilostazol and lomerizine hydrochloride, which resulted in functional improvement and recovery of vasoconstriction within 12 weeks.

View Article and Find Full Text PDF

Background: Neuromelanin-sensitive magnetic resonance imaging techniques have been developed but currently require relatively long scan times. The aim of this study was to assess the ability of black-blood delay alternating with nutation for tailored excitation-prepared T1-weighted variable flip angle turbo spin echo (DANTE T1-SPACE), which provides relatively high resolution with a short scan time, to visualize neuromelanin in the substantia nigra pars compacta (SNpc).

Methods: Participants comprised 49 healthy controls and 25 patients with Parkinson's disease (PD).

View Article and Find Full Text PDF

Objectives: The aim of this study was to assess the accuracy, reliability, and cerebral microbleed (CMB) detection performance of 2-minute quantitative susceptibility mapping (QSM) from 3-dimensional echo-planar imaging (3D-EPI).

Materials And Methods: Gadolinium phantom study was conducted using 3D-EPI, single-echo time (TE), and multi-TE gradient-recalled echo (GRE) sequences on two 3-T magnetic resonance (MR) scanners to assess the accuracy between measured and theoretical susceptibility values. The institutional review board approved this prospective study, and 40 healthy volunteers were enrolled with written consent between April 2018 and October 2019.

View Article and Find Full Text PDF

Carnitine palmitoyltransferase II (CPT II) deficiency is a rare inherited disorder related to recurrent episodes of rhabdomyolysis. The adult myopathic form of CPT II deficiency is relatively benign and difficult to diagnose. The point mutation S113L in CPT2 is very common in Caucasian patients, whereas F383Y is the most common mutation among Japanese patients.

View Article and Find Full Text PDF

A 67-year-old woman developed dropped head. Her neck was severely flexed, with prominent cervical paraspinal muscles, although no parkinsonism was observed. Brain MRI showed no significant findings.

View Article and Find Full Text PDF