Publications by authors named "Thoru Yamada"

Background: We aimed to confirm the association between slow brain wave activity typically described as "diffuse slowing" on standard electroencephalogram (EEG) and patient outcomes, including mortality.

Methods: This retrospective study was conducted with patient chart data from March 2015 to March 2017 at a tertiary care academic hospital in the midwestern United States. In total, 1,069 participants age ≥55 years on an inpatient floor or ICU received a standard 24-hour EEG.

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Background: We aimed to confirm the association between slow brain wave activity typically described as "diffuse slowing" on standard electroencephalogram (EEG) and patient outcomes, including mortality.

Methods: This retrospective study was conducted with patient chart data from March 2015 to March 2017 at a tertiary care academic hospital in the midwestern United States. In total, 1,069 participants age ≥55 years on an inpatient floor or ICU received a standard 24-hour EEG.

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Background: Delirium is common and dangerous, yet underdetected and undertreated. Current screening questionnaires are subjective and ineffectively implemented in busy hospital workflows. Electroencephalography (EEG) can objectively detect the diffuse slowing characteristic of delirium, but it is not suitable for high-throughput screening due to size, cost, and the expertise required for lead placement and interpretation.

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Aim: Delirium is common and dangerous among elderly inpatients; yet, it is underdiagnosed and thus undertreated. This study aimed to test the diagnostic characteristics of a noninvasive point-of-care device with two-channel (bispectral) electroencephalography (EEG) for the screening of delirium in the hospital.

Methods: Patients admitted to the University of Iowa Hospitals and Clinics were assessed for the presence of delirium with a clinical assessment, the Confusion Assessment Method for Intensive Care Unit and Delirium Rating Scale.

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Purpose: The somatosensory event-related potential N140 is thought to be related to selective attention. This study aimed to compare the somatosensory event-related potential N140 in healthy subjects to that in patients with stroke to determine whether N140 and attentiveness are associated in patients with stroke with or without hemispatial agnosia.

Materials And Methods: Normal somatosensory event-related potential N140 values were determined using data from ten healthy subjects.

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Electroconvulsive therapy (ECT) has been used in this country for more than 70 years, is still the most effective treatment in all of psychiatry, and is considered a very safe procedure to have under general anesthesia. Although most patients tolerate this procedure very well without complications, prolonged and/or tardive seizures or even status epilepticus can develop, which is a rare but serious complication of ECT. Tardive seizures are typically associated with electroencephalographic evidence of ictal activity and motor manifestations of the tonic-clonic activity.

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Processing of social and emotional information has been shown to be disturbed in schizophrenia. The biological underpinnings of these abnormalities may be explained by an abnormally functioning mirror neuron system. Yet the relationship between mirror neuron system activity in schizophrenia, as measured using an electroencephalography (EEG) paradigm, and socio-emotional functioning has not been assessed.

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Objective: To evaluate whether spinal cord intraoperative monitoring (IOM) with somatosensory and transcranial electrical motor evoked potentials (EPs) predict adverse surgical outcomes.

Methods: A panel of experts reviewed the results of a comprehensive literature search and identified published studies relevant to the clinical question. These studies were classified according to the evidence-based methodology of the American Academy of Neurology.

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Objectives: Spinal cord injury (SCI) causes anorectal problems, whose pathophysiology remains poorly characterized. A comprehensive method of evaluating spino-anorectal function is lacking. The aim of this study was to investigate the neuropathophysiology of bowel dysfunction in SCI by evaluating motor-evoked potentials (MEP) of anus and rectum following transspinal magnetic stimulation and anorectal physiology.

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We tested the validity of instructing patients to minimally contract the muscle to facilitate F-wave recording in clinical practice. In 12 healthy subjects, F waves were recorded from the first dorsal interosseous muscle at rest, during motor imagery, and at up to 30% of the maximal voluntary contraction (MVC). F-wave persistence increased significantly from 32.

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Purpose: To determine possible hemispheric differences of motor imagery in facilitating the anterior horn cells.

Methods: We conducted a side-to-side comparison of motor imagery to counter rest-induced suppression of spinal motor neurons in 10 right-handed healthy adults using the F wave as a measure of excitability. Studies consisted of sequential recording of F waves from the abductor pollicis brevis with 100 supramaximal stimuli applied to the median nerve on three consecutive sessions: (1) after standardized hand exercise to establish the baseline; (2) after immobilizing abductor pollicis brevis bilaterally for 3 hours, with one side assigned to relaxation task and the other side to motor imagery task; and (3) after standardized hand exercise to assess a recovery.

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Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for depression. Increased metabolism in the anterior cingulate cortex (ACC) is a known predictor for antidepressant response. The authors assessed whether increased theta power within the ACC predicts rTMS response in participants with vascular depression.

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To investigate how the sleep affects the recovery functions of somatosensory evoked potential, we studied somatosensory evoked potential recovery functions of the median nerve during awake to sleep in eight healthy adults, using the paired conditioning and test stimulus paradigm. The most notable difference between wakefulness and sleep was the much greater enhancement of parietal P26 and frontal P22 in sleep than in awake state at interstimulus intervals of 20 to 100 milliseconds of paired stimulus paradigm. Although the enhanced P26 and P22 were observed in control somatosensory evoked potential during sleep, the augmentation was much greater when conditioned by preceding stimulus.

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The correlation of serum melatonin levels and curve progression in adolescent idiopathic scoliosis, and the effects of melatonin therapy in scoliotic patients with reduced levels of endogenous melatonin were studied in 40 adolescent patients with moderate to severe idiopathic scoliosis. Of the scoliotic subjects, 28 had stable scoliosis and 12 had progressive scoliosis. Normal melatonin levels were derived from 25 age-matched control patients.

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Objective: Electroconvulsive therapy (ECT) is one of the most effective options available for treating depressive and psychotic symptoms in a variety of disorders. While the exact mechanism of ECT is unclear, it is known to increase metabolism and blood flow specifically in the anterior cingulate cortex (ACC). The ACC is a cortical generator of theta rhythms, which are abnormal in patients with depression and psychotic disorders.

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To test the hypothesis that the anterior horn cells become hypoexcitable in the absence of central drive, we recorded F waves simultaneously from the first dorsal interosseous (FDI) and the abductor digiti minimi (ADM) before and after volitionally inactivating one muscle (target) while periodically contracting the other muscle (control). In 14 healthy subjects, F waves recorded from the target muscle showed a progressive decrease in persistence and amplitude (whether counting all 100 trials or only detectable responses) after muscle relaxation for 1, 3, and 6 hours, followed by a quick recovery upon brief muscle contraction. We conclude that volitional inactivation suppresses the F waves of the target muscle without equally affecting the control muscle innervated by the same nerve.

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The etiology of idiopathic scoliosis is unknown. Scoliosis with many characteristics closely resembling those seen in idiopathic scoliosis has been produced in young chickens and bipedal rats after pinealectomy. In this study, we induced experimental scoliosis in C57BL/6J mice without pinealectomy and melatonin treatment suppressed the development of scoliosis.

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A young man, in whom narcolepsy was subsequently diagnosed, had the simultaneous onset of quadriparesis and a rapid eye movement (REM)-sleep polysomnographic pattern. During this REM-sleep pattern, a waking alpha EEG rhythm, appearing when he was asked to close his eyes, immediately attenuated when he was instructed to open his eyes, after which the REM-sleep pattern persisted. The juxtaposition of REM sleep patterns and reactive alpha rhythms are likely unique to sleep paralysis and may prove valuable in diagnosing narcolepsy.

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Study Design: This study was designed to investigate the difference of rib length of idiopathic scoliosis using experimentally induced scoliosis by pinealectomy in chickens.

Objective: To find whether the difference of rib length may play a role for the development of scoliosis in pinealectomized chickens.

Summary Of Background Data: In experimental and clinical studies, asymmetric growth of the rib has been considered to be one of factors for the development of idiopathic scoliosis.

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Recent studies provide valid criteria that help differentiate idiopathic narcolepsy from other disorders of excessive daytime somnolence [3]. Research to date suggests that idiopathic narcolepsy might properly be considered a disorder of excessive sleepiness with dysfunctional REM-sleep mechanisms, clinically evidenced as cataplexy and electrophysiologically recognized as SOREMPs. Given these criteria, a diagnosis can generally be made using a combination of history, PSG, and MSLT.

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The pathological mechanism of curve progression in idiopathic scoliosis is still obscure. In this study we investigated the pathological mechanism of idiopathic scoliosis in experimentally induced scoliosis in rats. A total 30 rats were divided into three groups: ten bipedal rats with a sham operation, which served as the control; ten quadrupedal rats with pinealectomy; and ten bipedal rats with pinealectomy.

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Studies of SSEP provide unique opportunities for investigating physioanatomic substrates of sensory pathway and cognitive functions of the sensory system. Progress of clinical investigation and application of SSEP have been stalled in more recent years, although SSEP still remain a useful tool for diagnosis of various neurologic disorders and for the monitoring of spinal cord function during surgery. Reflecting complex sensory system in human, scalp-recorded SSEP consists of multiple waves, having different distribution, amplitude, and latencies among different electrodes.

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An increase in the arousal threshold may predispose critically ill patients with obstructive sleep apnea (OSA) to prolonged apneas and death during sleep. We report two cases in whom polysomnographically documented OSA resulted in EEG changes compatible with cerebral hypoxemia with subsequent respective transient encephalopathy in one instance and death in the other.

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Evidence suggests that untreated obstructive sleep apnea (OSA) can lead to hypertension, cardiovascular disease, and stroke. Conversely, the systemic effects of a wide variety of critical illnesses can lead to CNS dysfunction, which can precipitate respiratory failure. Reported is a patient in whom an acute encephalopathy may have been responsible for transient OSA.

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