Altered brain network centrality in patients with late monocular blindness: a resting-state fMRI study

INTRODUCTION

The aim of the study was to investigate the underlying functional network brain activity changes in patients with late monocular blindness (MB) and the relationship with their clinical features using the voxel-wise degree centrality (DC) method.

MATERIAL AND METHODS

A total of 32 patients with MB (25 males and 7 females), and 32 healthy controls (HCs) (25 males and 7 females) closely matched in age, sex, and education, underwent resting-state functional magnetic resonance imaging scans. The DC method was used to assess local features of spontaneous brain activity. Correlation analysis was performed to explore the relationships between the observed mean DC signal values of the different areas and clinical features in these patients.

RESULTS

Compared with HCs, MB patients had significantly lower DC values in the bilateral cuneus/V1/V2, and significantly higher DC values in the left inferior temporal gyrus and bilateral medial frontal gyrus. However, there was no relationship between the observed mean DC values of the different brain areas and the behavioral performance.

CONCLUSIONS

Late monocular blindness involves brain function network dysfunction in many regions, which might indicate impairment of the visual cortex and other vision-related brain regions in the MBs.

Aberrant brain functional connectome in patients with obstructive sleep apnea

OBJECTIVE

Obstructive sleep apnea (OSA) is accompanied by widespread abnormal spontaneous regional activity related to cognitive deficits. However, little is known about the topological properties of the functional brain connectome of patients with OSA. This study aimed to use the graph theory approaches to investigate the topological properties and functional connectivity (FC) of the functional connectome in patients with OSA, based on resting-state functional magnetic resonance imaging (rs-fMRI).

METHODS

Forty-five male patients with newly diagnosed untreated severe OSA and 45 male good sleepers (GSs) underwent a polysomnography (PSG), clinical evaluations, and rs-fMRI scans. The automated anatomical labeling (AAL) atlas was used to construct the functional brain connectome. The topological organization and FC of brain functional networks in patients with OSA were characterized using graph theory methods and investigated the relationship between functional network topology and clinical variables.

RESULTS

Both the patients with OSA and the GSs exhibited high-efficiency "small-world" network attributes. However, the patients with OSA exhibited decreased σ, γ, Eglob; increased Lp, λ; and abnormal nodal centralities in several default-mode network (DMN), salience network (SN), and central executive network (CEN) regions. However, the patients with OSA exhibited abnormal functional connections between the DMN, SN, and CEN. The disrupted FC was significantly positive correlations with the global network metrics γ and σ. The global network metrics were significantly correlated with the Epworth Sleepiness Scale (ESS) score, Montreal Cognitive Assessment (MoCA) score, and oxygen desaturation index.

CONCLUSION

The findings suggest that the functional connectome of patients with OSA exhibited disrupted functional integration and segregation, and functional disconnections of the DMN, SN, and CEN. The aberrant topological attributes may be associated with disrupted FC and cognitive functions. These topological abnormalities and disconnections might be potential biomarkers of cognitive impairments in patients with OSA.

Disrupted small-world brain functional network topology in male patients with severe obstructive sleep apnea revealed by resting-state fMRI

PURPOSE

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder that can damage cognitive function. However, the functional network organization remains poorly understood. The aim of this study was to investigate the topological properties of OSA patients using a graph theoretical analysis.

PATIENTS AND METHODS

A total of 30 male patients with untreated severe OSA and 25 male education- and age-matched good sleepers (GSs) underwent functional magnetic resonance imaging (MRI) examinations. Clinical and cognitive evaluations were conducted by an experienced psychologist. GRETNA (a toolbox for topological analysis of imaging connectomics) was used to construct the brain functional network and calculate the small-world properties (γ, λ, σ, E_glob, and E_loc). Relationships between these small-world properties and clinical and neuropsychological assessments were investigated in OSA patients.

RESULTS

The networks of both OSA patients and GSs exhibited efficient small-world topology over the sparsity range of 0.05-0.40. Compared with GSs, the OSA group had significantly decreased γ, but significantly increased λ and σ. The OSA group's brain network showed significantly decreased E_glob (P<0.05) over the sparsity range of 0.09-0.15, but significantly increased E_loc over the sparsity range of 0.23-0.40. In OSA patients, γ was significantly negatively correlated with apnea-hypopnea index (AHI; r=-0.326, P=0.015) and Epworth Sleepiness Scale (ESS; r=-0.274, P=0.043), λ was significantly positively correlated with AHI (r=0.373, P=0.005) and ESS (r=0.269, P=0.047), and σ was significantly negatively correlated with AHI (r=-0.363, P=0.007) and ESS (r=-0.295, P=0.029).

CONCLUSION

Our results suggest that the high degree of local integration and integrity of the brain connections in OSA patients may be disrupted. The topological alterations of small-world properties may be the mechanism of cognitive impairment in OSA patients. In addition, σ, γ, and λ could be used as a quantitative physiological index for auxiliary clinical diagnoses.

Primary pulmonary plasmacytoma: a case report introduction

Background

Extramedullary plasmacytoma is a rare plasma cell neoplasm within soft tissue and without bone marrow involvement or other systemic characteristics of multiple myeloma. Primary pulmonary plasmacytoma is a rare type of extramedullary plasmacytoma.

Case presentation

A 48-year-old male with a tumor in the right middle ear was referred to our hospital. A routine chest X-ray was arranged and showed enlargement of the left lung hilum. His bilateral breathing sounded clear. A chest CT scan revealed a well-circumscribed mass. Pathological biopsy yielded a diagnosis of isolated pulmonary plasmacytoma.

Conclusions

This is the first presentation of primary pulmonary plasmacytoma with a solitary pulmonary nodule and no lymph node involvement.

Abnormal resting-state functional connectivity within the default mode network subregions in male patients with obstructive sleep apnea

BACKGROUND AND OBJECTIVE

Abnormal resting-state functional connectivity (rs-FC) between the central executive network and the default mode network (DMN) in patients with obstructive sleep apnea (OSA) has been reported. However, the effect of OSA on rs-FC within the DMN subregions remains uncertain. This study was designed to investigate whether the rs-FC within the DMN subregions was disrupted and determine its relationship with clinical symptoms in patients with OSA.

METHODS

Forty male patients newly diagnosed with severe OSA and 40 male education- and age-matched good sleepers (GSs) underwent functional magnetic resonance imaging (fMRI) examinations and clinical and neuropsychologic assessments. Seed-based region of interest rs-FC method was used to analyze the connectivity between each pair of subregions within the DMN, including the medial prefrontal cortex (MPFC), posterior cingulate cortex (PCC), hippocampus formation (HF), inferior parietal cortices (IPC), and medial temporal lobe (MTL). The abnormal rs-FC strength within the DMN subregions was correlated with clinical and neuropsychologic assessments using Pearson correlation analysis in patients with OSA.

RESULTS

Compared with GSs, patients with OSA had significantly decreased rs-FC between the right HF and the PCC, MPFC, and left MTL. However, patients with OSA had significantly increased rs-FC between the MPFC and left and right IPC, and between the left IPC and right IPC. The rs-FC between the right HF and left MTL was positively correlated with rapid eye movement (r=0.335, P=0.035). The rs-FC between the PCC and right HF was negatively correlated with delayed memory (r=-0.338, P=0.033).

CONCLUSION

OSA selectively impairs the rs-FC between right HF and PCC, MPFC, and left MTL within the DMN subregions, and provides an imaging indicator for assessment of cognitive dysfunction in OSA patients.

Altered regional homogeneity in patients with unilateral acute open-globe injury: a resting-state functional MRI study

OBJECTIVE

To investigate the underlying regional homogeneity (ReHo) brain activity changes in patients with unilateral acute open-globe injury (OGI) and their relationship with their clinical features.

PATIENTS AND METHODS

In total, 18 patients with acute OGI (16 males and two females) and 18 healthy controls (HCs; 16 males and two females) closely matched in age, sex, and education status participated in the study. Each subject underwent a resting-state functional magnetic resonance imaging scan. The ReHo method was used to assess local features of spontaneous brain activity. Receiver-operating characteristic curve was used to distinguish OGIs from HCs. The nonparametric statistical analysis was used to explore the relationship between the observed mean ReHo values of the different brain areas and the behavioral performance.

RESULTS

Compared with HCs, acute OGI patients had significantly increased ReHo values in the right cerebellum posterior lobe/lingual gyrus, left superior temporal gyrus/inferior frontal gyrus, left inferior frontal gyrus, left posterior cingulate cortex/precuneus, and left precentral operculum. However, there was no relationship between the observed mean ReHo values of the different brain areas and the behavioral performance.

CONCLUSION

Acute OGI may cause dysfunction in many brain regions, which may reflect the underlying pathologic mechanisms of acute vision loss in OGI patients.

Microstructural changes of the whole brain in patients with comitant strabismus: evidence from a diffusion tensor imaging study

OBJECTIVE

The aim of this study was to investigate the fractional anisotropy (FA) and mean diffusivity (MD) using a diffusion tensor imaging technique and whole-brain voxel-based analysis in patients with comitant strabismus.

PATIENTS AND METHODS

A total of 19 (nine males and ten females) patients with comitant strabismus and 19 age-, sex-, and education-matched healthy controls (HCs) underwent magnetic resonance imaging examination. Imaging data were analyzed using two-sample t-tests to identify group differences in FA and MD values. Patients with comitant strabismus were distinguishable from HCs by receiver operating characteristic curves.

RESULTS

Compared with HCs, patients with comitant strabismus exhibited significantly decreased FA values in the brain regions of the left superior temporal gyrus and increased values in the bilateral medial frontal gyrus, right globus pallidus/brainstem, and bilateral precuneus. Meanwhile, MD value was significantly reduced in the brain regions of the bilateral cerebellum posterior lobe and left middle frontal gyrus but increased in the brain regions of the right middle frontal gyrus and left anterior cingulate.

CONCLUSION

These results suggest significant brain abnormalities in comitant strabismus, which may underlie the pathologic mechanisms of fusion defects and ocular motility disorders in patients with comitant strabismus.

Functional connectivity of paired default mode network subregions in primary insomnia

OBJECTIVE

The aim of this study is to explore the resting-state functional connectivity (FC) differences between the paired default mode network (DMN) subregions in patients with primary insomnia (PIs).

METHODS

Forty-two PIs and forty-two age- and sex-matched good sleepers (GSs) were recruited. All subjects underwent the resting-state functional magnetic resonance imaging scans. The seed-based region-to-region FC method was used to evaluate the abnormal connectivity within the DMN subregions between the PIs and the GSs. Pearson correlation analysis was used to investigate the relationships between the abnormal FC strength within the paired DMN subregions and the clinical features in PIs.

RESULTS

Compared with the GSs, the PIs showed higher Pittsburgh Sleep Quality Index score, Hamilton Anxiety Rating Scale score, Hamilton Depression Rating Scale score, Self-Rating Depression Scale score, Self Rating Anxiety Scale score, Self-Rating Scale of Sleep score, and Profile of Mood States score (P<0.001). Compared with the GSs, the PIs showed significant decreased region-to-region FC between the medial prefrontal cortex and the right medial temporal lobe (t=-2.275, P=0.026), and between the left medial temporal lobe and the left inferior parietal cortices (t=-3.32, P=0.001). The abnormal FC strengths between the DMN subregions did not correlate with the clinical features.

CONCLUSION

PIs showed disrupted FC within the DMN subregions.

Aberrant spontaneous low-frequency brain activity in male patients with severe obstructive sleep apnea revealed by resting-state functional MRI

BACKGROUND

The majority of previous neuroimaging studies have demonstrated both structural and functional abnormalities in obstructive sleep apnea (OSA). However, few studies have focused on the regional intensity of spontaneous fluctuations during the resting state and the relationship between the abnormal properties and the behavioral performances. In the present study, we employed the amplitude of low-frequency fluctuation (ALFF) method to explore the local features of spontaneous brain activity in OSA patients (OSAs).

METHODS

Twenty-five untreated male severe OSAs and 25 age-matched and years-of-education-matched male good sleepers (GSs) were included in this study. The ALFF method was used to assess the local features of spontaneous brain activity. The mean signal values of the altered ALFF areas were analyzed with receiver operating characteristic curve. Partial correlation analysis was used to explore the relationship between the observed mean ALFF values of the different areas and the behavioral performances.

RESULTS

Compared with GSs, OSAs had significantly higher scores for body mass index, apnea-hypopnea index, arterial oxygen saturation <90%, arousal index, and Epworth Sleepiness Scale (ESS) score; furthermore, OSAs had significantly lower scores for rapid eye movement sleep and in the Montreal Cognitive Assessment (MoCA). Compared with GSs, OSAs showed significant lower-ALFF areas in the cluster of the right precuneus and bilateral posterior cingulate gyrus, as well as a higher-ALFF area in the left inferior frontal gyrus. The area under the curve values of the lower- and higher-ALFF areas were 0.90 and 0.93, respectively. Further diagnostic analysis exhibited that the sensibility and specificity of the two clusters were 80% and 92%, respectively. The mean signal value of the lower-ALFF cluster displayed significant positive correlations with lowest oxygen saturation (r=0.447, P=0.025) and MoCA score (r =0.405, P=0.045).

CONCLUSION

OSAs may involve in a dysfunction in the default mode network and an adaptive compensatory response in the frontal lobe, which reflect the underlying pathophysiology of cognitive impairment.

Altered intrinsic regional brain activity in male patients with severe obstructive sleep apnea: a resting-state functional magnetic resonance imaging study

BACKGROUND

Previous studies have demonstrated that obstructive sleep apnea (OSA) is associated with abnormal brain structural deficits. However, little is known about the changes in local synchronization of spontaneous activity in patients with OSA. The primary aim of the present study was to investigate spontaneous brain activity in patients with OSA compared with good sleepers (GSs) using regional homogeneity (ReHo) analysis based on resting-state functional magnetic resonance imaging (MRI).

METHODS

Twenty-five untreated male patients with severe OSA and 25 male GSs matched for age and years of education were included in this study. The ReHo method was calculated to assess the strength of local signal synchrony and was compared between the two groups. The observed mean ReHo values were entered into Statistical Package for the Social Sciences software to assess their correlation with behavioral performance.

RESULTS

Compared with GSs, patients with OSA showed significantly lower ReHo in the right medial frontal gyrus (BA11), right superior frontal gyrus (BA10), right cluster of the precuneus and angular gyrus (BA39), and left superior parietal lobule (BA7), and higher ReHo in the right posterior lobe of the cerebellum, right cingulate gyrus (BA23), and bilateral cluster covering the lentiform nucleus, putamen, and insula (BA13). The lower mean ReHo value in the right cluster of the precuneus and angular gyrus had a significant negative correlation with sleep time (r=-0.430, P=0.032), and higher ReHo in the right posterior lobe of the cerebellum showed a significant positive correlation with stage 3 sleep (r=0.458, P=0.021) and in the right cingulate gyrus showed a significant positive correlation with percent rapid eye movement sleep (r=0.405, P=0.045).

CONCLUSION

Patients with OSA showed significant regional spontaneous activity deficits in default mode network areas. The ReHo method is a useful noninvasive imaging tool for detection of early changes in cerebral ReHo in patients with OSA.

Altered intrinsic regional brain spontaneous activity and subjective sleep quality in patients with chronic primary insomnia: a resting-state fMRI study

STUDY OBJECTIVE

To prospectively explore the underlying regional homogeneity (ReHo) brain-activity deficit in patients with chronic primary insomnia (PCPIs) and its relationship with clinical features.

DESIGN

The ReHo method and Statistical Parametric Mapping 8 software were used to evaluate whether resting-state localized brain activity was modulated between PCPIs and good sleepers (GSs), and correlation analysis between altered regional brain areas and clinical features was calculated.

PATIENTS AND PARTICIPANTS

Twenty-four PCPIs (17 females, seven males) and 24 (12 females, 12 males) age-, sex-, and education-matched GSs.

MEASUREMENTS AND RESULTS

PCPIs disturbed subjective sleep quality, split positive mood, and exacerbated negative moods. Compared with GSs, PCPIs showed higher ReHo in left fusiform gyrus, and lower ReHo in bilateral cingulate gyrus and right cerebellum anterior lobe. Compared with female GSs, female PCPIs showed higher ReHo in the left fusiform gyrus and right posterior cingulate, and lower ReHo in the left cerebellum anterior lobe and left superior frontal gyrus. Compared with male GSs, male PCPIs showed higher ReHo in the right temporal lobe and lower ReHo in the bilateral frontal lobe. The fusiform gyrus showed strong positive correlations and the frontal lobe showed negative correlations with the clinical measurements.

CONCLUSION

The ReHo analysis is a useful noninvasive imaging tool for the detection of cerebral changes and the indexing of clinical features. The abnormal spontaneous activity areas provided important information on the neural mechanisms underlying emotion and sleep-quality impairment in PCPIs.