Reduced default mode network connectivity relative to white matter integrity is associated with poor cognitive outcomes in patients with idiopathic normal pressure hydrocephalus.

BACKGROUND: The aim of this study was to investigate whether default mode network (DMN) connectivity and brain white matter integrity at baseline were associated with severe cognitive impairments at baseline and poor cognitive outcomes after shunt placement in patients with idiopathic normal pressure hydrocephalus (iNPH). METHODS: Twenty consecutive patients with iNPH whose symptoms were followed for 6 months after shunt placement and 10 healthy controls (HCs) were enrolled. DMN connectivity and brain white matter integrity at baseline in the patients with iNPH and HCs were detected by using resting-state functional magnetic resonance imaging (MRI) with independent component analysis and diffusion tensor imaging, respectively, and these MRI indexes were compared between the patients with iNPH and HCs. Performance on neuropsychological tests for memory and executive function and on the gait test was assessed in the patients with iNPH at baseline and 6 months after shunt placement. We divided the patients with iNPH into the relatively preserved and reduced DMN connectivity groups using the MRI indexes for DMN connectivity and brain white matter integrity, and the clinical measures were compared between the relatively preserved and reduced DMN connectivity groups. RESULTS: Mean DMN connectivity in the iNPH group was significantly lower than that in the HC group and was significantly positively correlated with Rey auditory verbal learning test (RAVLT) immediate recall scores and frontal assessment battery (FAB) scores. Mean fractional anisotropy of the whole-brain white matter skeleton in the iNPH group was significantly lower than that in the HC group. The reduced DMN connectivity group showed significantly worse performance on the RAVLT at baseline and significantly worse improvement in the RAVLT immediate recall and recognition scores and the FAB scores than the preserved DMN connectivity group. Moreover, the RAVLT recognition score highly discriminated patients with relatively preserved DMN connectivity from those with relatively reduced DMN connectivity. CONCLUSIONS: Our findings indicated that iNPH patients with reduced DMN connectivity relative to the severity of brain white matter disruption have severe memory deficits at baseline and poorer cognitive outcomes after shunt placement. However, further larger-scale studies are needed to confirm these findings.

Brønsted acid-induced transannulation of the phytochemical zerumbone.

The sesquiterpene zerumbone was treated with HCl in ethyl acetate under the light-protected condition, and the time-dependent conversions were analyzed by gas chromatography. Nine products were isolated, and their structures were revealed by several NMR measurements such as 1H NMR, 13C{1H} NMR, distortionless enhancement by polarization transfer (DEPT)-135, 1H-1H correlation spectroscopy (COSY), 1H-13C heteronuclear multiple quantum coherence (HMQC), and 1H-13C heteronuclear multiple bond coherence (HMBC). The X-ray crystallography determined the stereochemistries of the three products and the two derivatives. After all, this acidic reaction was found to provide the (2Z,6E,10E)-isomer, the two HCl adducts, the two 7,6-bicyclic compounds, the valence isomers cycloheptatriene and norcaradiene, and the two dihydronaphthalenes. Based on the product analyses of the reactions from the isolated intermediates as well as the mechanistic considerations, these products were arranged into two paths: one of the paths ended in the two dihydronaphthalenes the same as previously reported under the Lewis acid condition; the other ended in the 7,6-bicyclic compound, the epimer of which was known. In addition, density functional theory (DFT) calculations indicated that the (2Z,6E,10E)-isomer was more stable than the (2E,6E,10Z)-isomer as well as that the activation energy for the isomerization at the C2-C3 double bond decreased to half by protonation. The closely examined reaction mechanisms under the simple acidic condition were established upon the intensive characterization of the intermediates and products, and these findings would add to the attractive value of zerumbone and would help understand the unknown biosynthetic pathway around sesquiterpenoids.

Satellite Sign: A Poor Outcome Predictor in Intracerebral Hemorrhage.

BACKGROUND: The presence of high-density starry dots around the intracerebral hemorrhage (ICH), which we termed as a satellite sign, is occasionally observed in CT. The relationship between ICH with a satellite sign and its functional outcome has not been identified. This study aimed to determine whether the presence of a satellite sign could be an independent prognostic factor for patients with ICH. METHODS: Patients with acute spontaneous ICH were retrospectively identified and their initial CT scans were reviewed. A satellite sign was defined as scattered high-density lesions completely separate from the main hemorrhage in at least the single axial slice. Functional outcome was evaluated using the modified Rankin Scale (mRS) at discharge. Poor functional outcome was defined as mRS scores of 3-6. Univariate and multivariate logistic regression analyses were applied to assess the presence of a satellite sign and its association with poor functional outcome. RESULTS: A total of 241 patients with ICH were enrolled in the study. Of these, 98 (40.7%) had a satellite sign. Patients with a satellite sign had a significantly higher rate of poor functional outcome (95.9%) than those without a satellite sign (55.9%, p < 0.0001). Multivariate logistic regression analysis revealed that higher age (OR 1.06; 95% CI 1.03-1.10; p = 0.00016), large hemorrhage size (OR 1.06; 95% CI 1.03-1.11; p = 0.00015), and ICH with a satellite sign (OR 13.5; 95% CI 4.42-53.4; p < 0.0001) were significantly related to poor outcome. A satellite sign was significantly related with higher systolic blood pressure (p = 0.0014), higher diastolic blood pressure (p = 0.0117), shorter activated partial thromboplastin time (p = 0.0427), higher rate of intraventricular bleeding (p < 0.0001), and larger main hemorrhage (p < 0.0001). CONCLUSIONS: The presence of a satellite sign in the initial CT scan is associated with a significantly worse functional outcome in ICH patients.

Subarachnoid small vein occlusion due to inflammatory fibrosis-a possible mechanism for cerebellar infarction in cryptococcal meningoencephalitis: a case report.

BACKGROUND: Cryptococcal meningoencephalitis (CM) causes cerebral infarction, typically, lacunar infarction in the basal ganglia. However, massive cerebral infarction leading to death is rare and its pathophysiology is unclear. We report a case of CM causing massive cerebellar infarction, which led to cerebral herniation and death. CASE PRESENTATION: A 56-year-old man who suffered from dizziness and gait disturbance for one month was admitted to our hospital and subsequently diagnosed with a cerebellar infarction. He had a past medical history of hepatitis type B virus infection and hepatic failure. Although the findings on magnetic resonance imaging (MRI) imitated an arterial infarction of the posterior inferior cerebellar artery, an accompanying irregular peripheral edema was observed. The ischemic lesion progressed, subsequently exerting a mass effect and leading to impaired consciousness. External and internal decompression surgeries were performed. Cryptococcus neoformans was confirmed in the surgical specimen, and the patient was diagnosed with CM. In addition, venule congestion in the parenchyma was observed with extensive fibrosis and compressed veins in the subarachnoid space. The patient died 26 days after admission. Autopsy revealed that pathological changes were localized in the cerebellum. CONCLUSION: C. neoformans can induce extensive fibrosis of the subarachnoid space, which may compress small veins mechanically inducing venule congestion and massive cerebral infarction. In such cases, the clinical course can be severe and even rapidly fatal. An atypical pattern of infarction on MRI should alert clinicians to the possibility of C. neoformans infection.

Microvascular decompression is effective for oculomotor nerve palsy caused by posterior cerebral artery compression: A case report.

Background: Oculomotor nerve palsy is often associated with diabetes mellitus or caused by compression by a cerebral aneurysm. Here, we report a rare case of oculomotor nerve palsy caused by compression by the posterior cerebral artery (PCA). Case Description: A 66-year-old woman suddenly developed diplopia and right blepharoptosis. Her symptoms suggested incomplete right oculomotor nerve palsy. Magnetic resonance imaging showed that a sharp curve in the right PCA had compressed the right oculomotor nerve. Microvascular decompression surgery was performed. Intraoperative findings showed that the P2 portion of the PCA had caused an indentation in the oculomotor nerve in the prepontine cistern. The transposition of the PCA with a prosthesis released the pressure. After the operation, her right blepharoptosis gradually improved. She had fully recovered by 48 days after the operation. Conclusion: Neurovascular compression (NVC) is recognized as the cause of hemifacial spasms, trigeminal neuralgia, and glossopharyngeal neuralgia. This case report demonstrated that NVC can also cause oculomotor nerve palsy. A high index of clinical suspicion can detect vascular compression of the oculomotor nerve. Prompt diagnosis and appropriate surgical management can achieve clinical improvement.

Hyperperfusion in the thalamus on arterial spin labelling indicates non-convulsive status epilepticus.

Non-convulsive status epilepticus describes the syndrome of unexplained impaired consciousness in critically ill patients. Non-convulsive status epilepticus is very likely to lead to delayed diagnosis and poor outcomes because of the absence of convulsive symptoms. EEG is essential for the diagnosis of non-convulsive status epilepticus to establish the association between periodic discharges and rhythmic delta activity in addition to ictal epileptiform discharges according to the Salzburg criteria. Arterial spin labelling, a type of perfusion MRI, has been applied for rapid and non-invasive evaluation of the ictal state. Ictal cerebral cortical hyperperfusion is the most common finding to demonstrate focal onset seizures. Hyperperfusion of the thalamus on single photon emission computed tomography was found in patients with impaired awareness seizures. We hypothesized that thalamocortical hyperperfusion on arterial spin labelling identifies non-convulsive status epilepticus and such thalamic hyperperfusion specifically associates with periodic/rhythmic discharges producing impaired consciousness without convulsion. We identified 27 patients (17 females; age, 39-91 years) who underwent both arterial spin labelling and EEG within 24 h of suspected non-convulsive status epilepticus. We analysed 28 episodes of suspected non-convulsive status epilepticus and compared hyperperfusion on arterial spin labelling with periodic/rhythmic discharges. We evaluated 21 episodes as a positive diagnosis of non-convulsive status epilepticus according to the Salzburg criteria. We identified periodic discharges in 15 (12 lateralized and 3 bilateral independent) episodes and rhythmic delta activity in 13 (10 lateralized, 1 bilateral independent and 2 generalized) episodes. Arterial spin labelling showed thalamic hyperperfusion in 16 (11 unilateral and 5 bilateral) episodes and cerebral cortical hyperperfusion in 24 (20 unilateral and 4 bilateral) episodes. Thalamic hyperperfusion was significantly associated with non-convulsive status epilepticus (P = 0.0007; sensitivity, 76.2%; specificity, 100%), periodic discharges (P < 0.0001; 93.3%; 84.6%), and rhythmic delta activity (P = 0.0006; 92.3%; 73.3%). Cerebral cortical hyperperfusion was significantly associated with non-convulsive status epilepticus (P = 0.0017; 100%; 57.1%) and periodic discharges (P = 0.0349; 100%; 30.8%), but not with rhythmic delta activity. Thalamocortical hyperperfusion could be a new biomarker of non-convulsive status epilepticus according to the Salzburg criteria in critically ill patients. Specific thalamic hyperexcitability might modulate the periodic discharges and rhythmic delta activity associated with non-convulsive status epilepticus. Impaired consciousness without convulsions could be caused by predominant thalamic hyperperfusion together with cortical hyperperfusion but without ictal epileptiform discharges.

Visual activation positron emission tomography for presurgical evaluation of occipital lobe epilepsy--case report.

A 14-year-old boy suffered from daily epileptic seizures originating from the left polymicrogyric occipital cortex. Visual activation positron emission tomography (PET) was used to map the function of the occipital cortex presurgically. Loss of visual function in the left occipital cortex was suggested by both visual activation PET and electrical cortical stimulation. Left occipital lobectomy resulted in a completely seizure-free status without deterioration in the visual function. Preoperative evaluation of the visual function in the epileptogenic occipital cortex by activation studies using PET or functional magnetic resonance imaging is the key to the successful surgical treatment of occipital lobe epilepsy.

Temporo-parietal theta activity correlates with misery perfusion in arterial occlusive disease.

OBJECTIVE: Temporo-parietal theta activity (TPTA), often detected in hemispheres with internal carotid (ICA) or middle cerebral artery (MCA) occlusive lesions, is more clearly separated from occipital alpha activity by magnetoencephalography (MEG) than electroencephalography. The present study investigated whether TPTA is correlated with misery perfusion, a surgically correctable type of hemodynamic impairment. METHODS: Awake MEG was measured in 56 patients with ICA or MCA occlusive lesions. Regional cerebral blood flow (rCBF) and regional cerebrovascular reactivity (rCVR) to acetazolamide were measured in the MCA territory by xenon-133 single-photon emission computed tomography. MEG was repeated in 10 patients after vascular reconstruction surgery. RESULTS: Fourteen patients showed TPTA in the lesion hemisphere (n=13) or bilaterally (n=1). The presence of TPTA was significantly correlated with both reduced rCBF and reduced rCVR (P=0.0009). After surgery, TPTA disappeared in 7 of the 10 studied patients. CONCLUSIONS: The presence of TPTA suggests misery perfusion, which is characterized by reduced rCBF and reduced rCVR. SIGNIFICANCE: MEG can detect the presence of reversible and surgically remediable cerebral ischemia before the development of complete infarction.

Neuromagnetic measurement of unilateral temporo-parietal theta rhythm in patients with internal carotid artery occlusive disease.

Rhythmic theta activity detected by electroencephalography (EEG) may be correlated with cerebrovascular brain diseases. Magnetoencephalography (MEG) has higher sensitivity and spatial resolution than conventional scalp EEG, so may be a better method to detect theta rhythm in patients with internal carotid artery (ICA) occlusive disease. Simultaneous EEG and MEG were performed in the awake state in 48 patients with unilateral (n = 42) or bilateral (n = 6) stenotic lesions (more than 60% occlusion) of the ICA (n = 47) or middle cerebral artery (n = 7), and in 27 age-matched healthy normal subjects. No subject had severe neurological deficits. MEG detected the theta rhythm (6-8 Hz) in 14 of 48 patients: ipsilateral to the stenotic or occluded side in 13 hemispheres and bilaterally in one patient with unilateral lesion. The source of the MEG theta rhythm was estimated in the dorsolateral temporo-parietal area, regardless of the location of infarct foci or the stenotic portion of the ICA system. The temporo-parietal theta rhythm was separated from the occipital alpha rhythm by frequency and distribution in MEG. The theta rhythm was found in only two patients by EEG, as well as by MEG. MEG provided better separation of this theta rhythm from the occipital alpha rhythm. Neither MEG nor EEG detected this theta rhythm in the normal subjects. Unilateral temporo-parietal theta rhythm is correlated with the hemisphere with ICA occlusive disease. This rhythm may indicate mild or subclinical abnormalities in the ICA system. MEG is superior to EEG for the detection and localization of theta rhythm.