気分状態に依存しない双極性障害と大うつ病性障害における脳梁の白質微細構造の差異

OBJECTIVE: It is difficult to distinguish between bipolar disorder and major depressive disorder (MDD) in patients lacking a clear history of mania. There is an urgent need for an objective biomarker for differential diagnosis. Using diffusion tensor imaging, this study investigated the differences in the brain white matter microstructure between patients with bipolar disorder and MDD. METHODS: Participants included 16 patients with bipolar disorder and 23 patients with MDD having depressed or euthymic states based on DSM-IV-TR criteria and 23 healthy volunteers. Whole-brain voxel-based morphometric analysis was used to detect any significant differences in fractional anisotropy between patients with bipolar disorder and MDD. The study was conducted between August 2011 and July 2015. RESULTS: We found a significant decrease in fractional anisotropy values in the anterior part of the corpus callosum in patients with bipolar disorder compared with MDD (P < .001), which did not depend on the patients' affective state. This decrease was associated with increased radial diffusivity values (P < .05), which was also found in patients with bipolar disorder when compared with healthy volunteers (P < .05). We predicted bipolar disorder and MDD in all patients using the fractional anisotropy values, with a correct classification rate of 76.9%. CONCLUSIONS: The present study revealed that patients with bipolar disorder have microstructural abnormalities in the corpus callosum during depressed or euthymic states, which may deteriorate the exchange of emotional information between the cerebral hemispheres, resulting in emotional dysregulation. Our results indicate the possible use of diffusion tensor imaging as a differential diagnostic tool.博士（医学）・甲第662号・平成29年3月15日© Copyright 2017 Physicians Postgraduate Press, Inc.発行元の規定により、本文の登録不可。本文は以下のURLを参照 "http://dx.doi.org/10.4088/JCP.15m09851" （※全文閲覧は学内限定

Asymmetry, sex differences and age-related changes in the white matter in the healthy elderly: a tract-based study

<p>Abstract</p> <p>Background</p> <p>Hemispherical asymmetry, sex differences and age-related changes have been reported for the human brain. Meanwhile it was still unclear the presence of the asymmetry or sex differences in the human brain occurred whether as a normal development or as consequences of any pathological changes. The aim of this study was to investigate hemispherical asymmetry, sex differences and age-related changes by using a tract-based analysis in the nerve bundles.</p> <p>Methods</p> <p>40 healthy elderly subjects underwent magnetic resonance diffusion tensor imaging, and we calculated fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values along the major white matter bundles.</p> <p>Results</p> <p>We identified hemispherical asymmetry in the ADC values for the cingulate fasciculus in the total subject set and in males, and a sex difference in the FA values for the right uncinate fasciculus. For age-related changes, we demonstrated a significant increase in ADC values with advancing age in the right cingulum, left temporal white matter, and a significant decrease in FA values in the right superior longitudinal fasciculus.</p> <p>Conclusion</p> <p>In this study, we found hemispherical asymmetry, sex differences and age-related changes in particular regions of the white matter in the healthy elderly. Our results suggest considering these differences can be important in imaging studies.</p

Brain structural changes and neuropsychological impairments in male polydipsic schizophrenia

BACKGROUND: Polydipsia frequently occurs in schizophrenia patients. The excessive water loading in polydipsia occasionally induces a hyponatremic state and leads to water intoxication. Whether polydipsia in schizophrenic patients correlates with neuropsychological impairments or structural brain changes is not clear and remains controversial. METHODS: Eight polydipsic schizophrenia patients, eight nonpolydipsic schizophrenia patients, and eight healthy controls were recruited. All subjects underwent magnetic resonance imaging (MRI) and neuropsychological testing. Structural abnormalities were analyzed using a voxel-based morphometry (VBM) approach, and patients’ neuropsychological function was assessed using the Brief Assessment of Cognition in Schizophrenia, Japanese version (BACS-J). RESULTS: No significant differences were found between the two patient groups with respect to the clinical characteristics. Compared with healthy controls, polydipsic patients showed widespread brain volume reduction and neuropsychological impairment. Furthermore, the left insula was significantly reduced in polydipsic patients compared with nonpolydipsic patients. These nonpolydipsic patients performed intermediate to the other two groups in the neuropsychological function test. CONCLUSIONS: It is possible that polydipsia or the secondary hyponatremia might induce left insula volume reduction. Furthermore, this structural brain change may indirectly induce more severe neuropsychological impairments in polydipsic patients. Thus, we suggest that insula abnormalities might contribute to the pathophysiology of polydipsic patients

Type D Syndrome of Inappropriate Antidiuretic Hormone Secretion in a Schizophrenia Patient with Polydipsia

A 55-year-old man with schizophrenia developed water intoxication due to primary polydipsia. His manner of antidiuretic hormone secretion was investigated by water loading and infusion of hypertonic saline to clarify the form of the syndrome of inappropriate antidiuretic hormone secretion. The plasma antidiuretic hormone level, which may be involved in the occurrence of water intoxication, was consistently low in this patient, and linked to type D syndrome of inappropriate antidiuretic hormone secretion, designated “hypovasopressinemic antidiuresis”. Although this type is not common, it should be considered as a pathophysiology for water intoxication in schizophrenia patients

Increased binding of 5-HT1A receptors in a dissociative amnesic patient after the recovery process.

Dissociative amnesia is characterized by an inability to retrieve information already saved in memories. 5-HT has some role in neural regulatory control and may be related to the recovery from dissociative amnesia. To examine the role of 5-HT1A receptors in the recovery from dissociative amnesia, we performed two positron emission tomography (PET) scans on a 30-year-old patient of dissociative amnesia using [(11)C]WAY-100635, the first at amnesic state, and the second at the time he had recovered. Exploratory voxel-based analysis (VBA) was performed using SPM software. 5-HT1A BPND images were compared between the patient at amnesic and recovery states and healthy subjects (14 males, mean age 29.8±6.45) with Jack-knife analysis. 5-HT1A receptor bindings of the patient at the recovery state were significantly higher than those of healthy subjects in the right superior and middle frontal cortex, left inferior frontal and orbitofrontal cortex and bilateral inferior temporal cortex. The increase in BPND values of recovery state was beyond 10% of those of amnesia state in these regions except in the right superior frontal cortex. We considered that neural regulatory control by the increase of 5-HT1A receptors in cortical regions played a role in the recovery from dissociative amnesia

アルツハイマー型認知症における白質経時変化の検討 : トラクトグラフィーを用いた研究

Alzheimer's disease (AD) classically presents with gray matter atrophy, as well as feature significant white matter abnormalities. Previous evidence indicates the overall burden of these pathological changes continues to advance as the disease progresses. The aim of this study was to investigate whether pathological alterations of white matter tracts correlate with the course of AD disease progression. 35 AD patients and 29 normal controls were recruited to the study and administered baseline magnetic resonance diffusion tensor imaging (DTI) acquisition and a cognitive function assessment at the time of initial evaluation. Subjects were re-evaluated with secondary DTI scan and cognitive function assessment at intervals of about 1.5 years on average. For the DTI acquired scans, we calculated diffusion tensor parameters, fractional anisotropy (FA), apparent diffusion coefficient (ADC), radial diffusivity (DR), and axial diffusivity (DA) along with the uncinate fasciculus (UNC), the inferior longitudinal fasciculus (ILF), and the inferior occipitofrontal fasciculus (IOFF). Compared to baseline, a significant mean FA reduction of the bilateral UNC, as well as a significant mean DR increase of the left UNC, was evident in AD patients at follow-up. Compared with normal controls, AD patients exhibited significant diffusion parameter abnormalities in their UNC, ILF, and IOFF. Taken together, these results indicate that progressive pathological white matter alterations can be quantified using the DTI parameters utilized here and may prove to be a useful biological marker for monitoring the pathophysiological course of AD.博士（医学）・甲第603号・平成25年11月27