Abnormal amplitude of low-frequency fluctuations and functional connectivity in patients with primary dysmenorrhea

BackgroundPrevious neuroimaging studies demonstrated that patients with primary dysmenorrhea (PD) exhibited dysfunctional resting-state brain activity. However, alterations of dynamic brain activity in PD patients have not been fully characterized.PurposeOur study aimed to assess the effect of long-term menstrual pain on changes in static and dynamic neural activity in PD patients.Material and MethodsTwenty-eight PD patients and 28 healthy controls (HCs) underwent resting-state magnetic resonance imaging scans. The amplitude of low-frequency fluctuations (ALFF) and dynamic ALFF was used as classification features in a machine learning approach involving a support vector machine (SVM) classifier.ResultsCompared with the HC group, PD patients showed significantly increased ALFF values in the right cerebellum_crus2, right rectus, left supplementary motor area, right superior frontal gyrus, right supplementary motor area, and left superior frontal medial gyrus. Additionally, PD patients showed significantly decreased ALFF values in the right middle temporal gyrus and left thalamus. PD patients also showed significantly increased dALFF values in the right fusiform, Vermis_10, right middle temporal gyrus, right putamen, right insula, left thalamus, right precentral gyrus, and right postcentral gyrus. Based on ALFF and dALFF values, the SVM classifier achieved respective overall accuracies of 96.36% and 85.45% and respective areas under the curve of 1.0 and 0.95.ConclusionPD patients demonstrated abnormal static and dynamic brain activities that involved the default mode network, sensorimotor network, and pain-related subcortical nuclei. Moreover, ALFF and dALFF may offer sensitive biomarkers for distinguishing patients with PD from HCs.

Objective To evaluate the severe traumatic brain injury (sTBI) in coma patients by amplitude of low-frequency fluctuation (ALFF) of resting-state functional magnetic resonance imaging (rs-fMRI) , functional connectivity (FC) methods and magnetic resonance diffusion tensor imaging (DTI) , and to predict its prognosis. Methods Twenty-one sTBI patients (study group) and 21 healthy subjects (control group) with matched education degree, age and gender were examined by rs-fMRI and DTI. The differences in ALFF, FC and anisotropy (FA) between the two groups were compared. According to the prognosis of sTBI patients, the patients in the study group were divided into awake group and coma group, and the differences in ALFF and FC between the two groups were compared. Results Compared with the normal control group, the ALFF and FC values in multiple regions of default network in the study group significantly decreased. The FA values in semioval center, genu and splenium of corpus callosum, and anterior and posterior limbs of internal capsule significantly decreased (P<0.05) . Compared with the coma group, the ALFF and FC values in multiple regions of default network in the awake group significantly increased (P<0.05) . Conclusion The ALFF and FC values increase in brain regions of default network in sTBI patients with better prognosis. Key words: Functional magnetic resonance imaging; Craniocerebral injury; Coma; Prognosis prediction

ABSTRACTAimsThere is limited research on predicting the recovery of consciousness in patients with acute disorders of consciousness (aDOC). The purpose of this study is to investigate the altered characteristics of the local neuronal activity indicated by the amplitude of low‐frequency fluctuations (ALFF) and functional connectivity (FC) of the hippocampus network in patients with aDOC caused by neurological injury and to explore whether these characteristics can predict the recovery of consciousness.MethodsThirty‐seven patients with aDOC were included, all of whom completed resting‐state functional magnetic resonance imaging (rsfMRI) scans. The patients were divided into two groups based on prognosis of consciousness recovery, 24 patients were in prolonged disorders of consciousness (pDOC) and 13 in emergence from minimally conscious state (eMCS) at 3 months after neurological injury. Univariable and multivariate logistic regression analyses were used to investigate the clinical indicators affecting patients' recovery of consciousness. The ALFF values and FC of the hippocampal network were compared between patients with pDOC and those with eMCS. Additionally, we employed the support vector machine (SVM) method to construct a predictive model for prognosis of consciousness based on the ALFF and FC values of the aforementioned differential brain regions. The accuracy (ACC), area under the curve (AUC), sensitivity, and specificity were used to evaluate the efficacy of the model.ResultsThe FOUR score at onset and the length of mechanical ventilation (MV) were found to be significant influential factors for patients who recovered to eMCS at 3 months after onset. Patients who improved to eMCS showed significantly increased ALFF values in the right calcarine gyrus, left lingual gyrus, right middle temporal gyrus, and right precuneus compared to patients in a state of pDOC. Furthermore, significant increases in FC values of the hippocampal network were observed in the eMCS group, primarily involving the right lingual gyrus and bilateral precuneus, compared to the pDOC group. The predictive model constructed using ALFF alone or ALFF combined with FC values from the aforementioned brain regions demonstrated high accuracies of 83.78% and 81.08%, respectively, with AUCs of 95% and 94%, sensitivities of 0.92 for both models, and specificities of 0.92 for both models in predicting the recovery of consciousness in patients with aDOC.ConclusionThe present findings demonstrate significant differences in the local ALFF and FC values of the hippocampus network between different prognostic groups of patients with aDOC. The constructed predictive model, which incorporates ALFF and FC values, has the potential to provide valuable insights for clinical decision‐making and identifying potential targets for early intervention.

Purpose: The current study aimed to explore the central mechanism of primary dysmenorrhea (PD) by investigating the alterations in resting state amplitude of low-frequency fluctuation (ALFF) and regional cerebral blood flow (CBF) between PD patients and healthy controls (HCs).Patients and methods: A total of 34 female subjects including 20 PD patients and 14 HCs underwent resting-state functional magnetic resonance imaging (rs-fMRI) and arterial spin labeling technique (ASL) MRI during menstrual phase. Subsequently, the differences in ALFF and CBF were compared in the two groups. The visual analog scores for pain (VAS-P) and for anxiety (VAS-A) were applied to assess cramping pain and related symptoms in PD patients. Finally, Pearson’s correlation analysis was performed to analyze relationships between the neuroimaging findings and clinical characteristics.Results: Compared to HCs, PD patients had decreased ALFF in the right cerebellum posterior lobe, right middle temporal gyrus, right parahippocampal gyrus, right hippocampus, right brainstem and left parietal lobe. In addition, elevated CBF values were observed in the right inferior frontal gyrus, right precentral gyrus, and right superior temporal gyrus. There was no significant correlation between ALFF, CBF values and clinical characteristics including onset age of dysmenorrhea, VAS-A, and VAS-P in PD patients.Conclusion: The preliminary alterations of ALFF and CBF values in PD patients were observed in different pain-related brain regions, which were involved in multiple dimensions of pain and pain modulation. The combination of rs-fMRI and ASL MRI might provide complementary information for a better understanding of the central mechanism in PD.

Objective To explore the changes of rest-state functional MRI (fMRI) features in patients with Parkinson's disease. Methods Twelve patients with Parkinson's disease, collected in our hospital from September 2013 to March 2014, and 12 volunteers (controls) were recruited. The fMRI based on blood oxygen level dependent (BOLD) was performed at resting state; the differences of amplitude of low frequency fluctuation (ALFF) and regional homogeneity (ReHo) were statistically analyzed; and the correlations of values of ALFF and ReHo with uniformed Parkinsonism rating scale (UPDRS) scores and Hoehn-Yahr (H-Y) grading were analyzed. Results PD patients exhibited increased ALFF values in the limbic lobe, the right parahippocampal gyrus and the right middle temporal pole, and reduced ALFF values in the left thalamus as compared with the controls. PD patients exhibited increased ReHo values in the superior medial frontal gyrus, the left middle frontal gyrus, brodmann area (BA) 9 and medial frontal gyrus, and reduced ReHo values in the left rolandic, the left superior temporal gyrus and insula lobe as compared with the controls. ALFF values were positively correlated with the UPDRS III scores in the right posterior cerebellum lobe and cerebellar tonsil. ALFF values and H-Y grading were negatively correlated on the left superior frontal gyrus. Negative correlation was noted between the ReHo values and UPDRS III scores in the right superior temporal gyrus and insular lobe. Positive correlation was noted between the ReHo values and H-Y grading in medial frontal gyrus, limbic lobe, anterior cingulate, medial orbitofrontal area, middle superior frontal gyrus, BA32, left superior frontal gyrus and BA10. Conclusion By resting-state fMRI, abnormal brain function in Parkinson's disease was noted; ReHo and ALFF showed abnormal changes in the connection of neuronal networks, and the compensatory response may lead to the increased brain function. Key words: Parkinson’s disease; Functional MR imaging; Regional homogeneity; Amplitude of low frequency fluctuation

Lever positioning manipulation alters real-time brain activity in patients with lumbar disc herniation: An amplitude of low-frequency fluctuation and regional homogeneity study

Evaluation of Prognosis in Patients with Severe Traumatic Brain Injury Using Resting-State Functional Magnetic Resonance Imaging

Objective To investigate the changes of brain functions in hemodialysis (HD) patients with end-stage renal disease (ESRD) using resting-state functional magnetic resonance imaging (rs-fMRI) with amplitude of low frequency fluctuation (ALFF)algorithm.Methods Sixty-four HD-ESRD patients and forty-five sex and age-matched healthy controls were included in the rs-fMRI study.All subjects were given neuropsychological tests [number connection type-A (NCT-A) and digit symbol test (DST)] to evaluate cognitive function.Laboratory tests,including serum creatinine and urea,were performed in all HD-ESRD patients.SPM8 and REST1.6 software were used to process the data and to generate all subjects' ALFF maps.One-sample t test was performed to show the spatial pattern of ALFF in each group.Two-sample t test was used to determine the ALFF differences between patients and healthy controls.In addition,Pearson correlation analysis was performed among the ALFF values of significant brain regions and neuropsychological test scores,disease and dialvsis durations,serum creatinine and urea levels.Results Within each group,bilateral precuneus,superior frontal gyrus,middle frontal gyrus,inferior parietal lobule,cuneus and superior temporal gy rus showed higher ALFF values than the global mean ALFF value.Compared with the healthy controls,HD-ESRD patients presented decreased ALFF in bilateral precuneus,frontal lobes,middle temporal gyrus,and right inferior parietal lobule (voxel volumes:270-6 804 mm3,t =-7.41--3.78,all P＜0.01).The DST scores of HD-ESRD patients positively correlated with ALFF values in right middle frontal gyrus (r=0.273,P＜0.05).The disease durations negatively correlated with ALFF values in bilateral precuneus,left supramarginal gyrus and left medial frontal gyrus (r =-0.301,-0.278,-0.298,-0.287,allP＜0.05).The dialysis durations,NCT-A values,serum creatinine and urea levels of HD-ESRD patients showed no significant correlation with ALFF values (all P＞0.05).Conclusions HD-ESRD patients have abnormal ALFF values in several brain areas mainly located in default mode network (DMN),suggesting impaired spontaneous neural activity in HD-ESRD patients,and disease durations might be a risk factor for impaired spontaneous neural activity in HD-ESRD patients. Key words: Nephrosis; Dialysis; Magnetic resonance imaging

Objective:To evaluate the effects of sex hormones on amplitude of low-frequency fluctuation (ALFF) in brain regions related to cognition in perimenopausal women.Methods:This cross-sectional study involved 25 perimenopausal women and 25 premenopausal women who underwent behavioral evaluations, sex hormone level measurements, and functional magnetic resonance imaging (fMRI). All data and ALFF analyses were preprocessed using the Data Processing Assistant for Resting-State fMRI. Statistical analyses were performed using the Resting-State fMRI Data Analysis Toolkit to explore the differences in ALFF between perimenopausal and premenopausal women. The gray matter volume (GMV) values extracted from brain regions (regions of interest) with significantly different ALFF values between the perimenopausal and premenopausal groups were compared. We analyzed the correlations of the ALFF and GMV values of these regions of interest with the results of behavioral evaluations and sex hormone levels in the two groups.Results:Compared with the premenopausal group, the perimenopausal group showed significant ALFF increase in the left gyrus rectus. Regions with decreased ALFF in the perimenopausal group included the left superior temporal gyrus, left inferior frontal gyrus, and left insula. The GMV values of the left gyrus rectus and left superior temporal gyrus were reduced in perimenopausal women. Furthermore, the estradiol level was negatively correlated with the ALFF value of the left gyrus rectus in perimenopausal women.Conclusions:The ALFF and GMV values of certain brain regions related to cognitive function were changed in perimenopausal women. Such functional brain alterations may provide more information regarding the mechanism of cognitive dysfunction in perimenopausal women.

The purpose of this study is to investigate brain functional changes in patients with intermittent exotropia (IXT) by analyzing the amplitude of low-frequency fluctuation (ALFF) of brain activity and functional connectivity (FC) using resting-state functional magnetic resonance imaging (rs-fMRI). There were 26 IXT patients and 22 age-, sex-, education-, and handedness-matched healthy controls (HCs) enrolled who underwent rs-fMRI. The ALFF, fractional ALFF (fALFF) values in the slow 4 and slow 5 bands, and FC values were calculated and compared. The correlations between ALFF/fALFF values in discrepant brain regions and clinical features were evaluated. Compared with HCs, ALFF/fALFF values were significantly increased in the right angular gyrus (ANG), supramarginal gyrus (SMG), inferior parietal lobule (IPL), precentral gyrus (PreCG), and the bilateral inferior frontal gyri (IFG), and decreased in the right precuneus gyrus (PCUN), left middle occipital gyrus (MOG), and postcentral gyrus (PoCG) in IXT patients. The Newcastle Control Test score was negatively correlated with ALFF values in the right IFG (r = −0.738, p < 0.001). The duration of IXT was negatively correlated with ALFF values in the right ANG (r = −0.457, p = 0.049). Widespread increases in FC were observed between brain regions, mainly including the right cuneus (CUN), left superior parietal lobule (SPL), right rolandic operculum (ROL), left middle temporal gyrus (MTG), left IFG, left median cingulate gyrus (DCG), left PoCG, right PreCG, and left paracentral gyrus (PCL) in patients with IXT. No decreased FC was observed. Patients with IXT exhibited aberrant intrinsic brain activities and FC in vision- and eye movement-related brain regions, which extend current understanding of the neuropathological mechanisms underlying visual and oculomotor impairments in IXT patients.

How cortical functional reorganization occurs after hearing loss in preschool children with congenital sensorineural hearing loss (CSNHL) is poorly understood. Therefore, we used resting-state functional MRI (rs-fMRI) to explore the characteristics of cortical reorganization in these patents. Sixty-three preschool children with CSNHL and 32 healthy controls (HCs) were recruited, and the Categories of Auditory Performance (CAP) scores were determined at the 6-month follow-up after cochlear implantation (CI). First, rs-fMRI data were preprocessed, and amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) were calculated. Second, whole-brain functional connectivity (FC) analysis was performed using bilateral primary auditory cortex as seed points. Finally, Spearman correlation analysis was performed between the differential ALFF, ReHo and FC values and the CAP score. ALFF analysis showed that preschool children with CSNHL had lower ALFF values in the bilateral prefrontal cortex and superior temporal gyrus than HCs, but higher ALFF values in the bilateral thalamus and calcarine gyrus. And correlation analysis showed that some abnormal brain regions were weak negatively correlated with CAP score (p < 0.05). The ReHo values in the bilateral superior temporal gyrus, part of the prefrontal cortex and left insular gyrus were lower, whereas ReHo values in the bilateral thalamus, right caudate nucleus and right precentral gyrus were higher, in children with CSNHL than HCs. However, there was no correlation between ReHo values and the CAP scores (p < 0.05). Using primary auditory cortex (PAC) as seed-based FC further analysis revealed enhanced FC in the visual cortex, proprioceptive cortex and motor cortex. And there were weak negative correlations between the FC values in the bilateral superior temporal gyrus, occipital lobe, left postcentral gyrus and right thalamus were weakly negatively correlated and the CAP score (p < 0.05). After auditory deprivation in preschool children with CSNHL, the local functions of auditory cortex, visual cortex, prefrontal cortex and somatic motor cortex are changed, and the prefrontal cortex plays a regulatory role in this process. There is functional reorganization or compensation between children's hearing and these areas, which may not be conducive to auditory language recovery after CI in deaf children.

IntroductionThe current study aimed to depict intrinsic structural changes and the spontaneous brain activity patterns in voxel level in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD) by using diffusion-tensor imaging and resting-state functional magnetic resonance (MR) imaging with an amplitude of low-frequency fluctuations (ALFF) algorithm and their clinical relevance.Materials and MethodsIn the study, the diffusion-tensor imaging and resting-state functional MR imaging were performed in forty-two hemodialysis patients with ESRD and 42 healthy control subjects. Neuropsychological and laboratory tests were performed in all subjects. ALFF, fraction anisotropy (FA), and mean diffusivity (MD) values were compared between the two groups. Correlations between ALFF, FA or MD values, and clinical markers were analyzed.ResultsWe found that ESRD patients exhibited significantly lower ALFF values in multiple areas, including medial frontal gyrus, limbic lobe, superior frontal gyrus, bilateral lingual gyri, occipital lobe, parahippocampal gyrus, precuneus, while increased ALFF values in medial frontal gyrus than healthy controls. FA values were decreased in medial frontal gyrus, parietal lobe, and left precuneus regions in the ESRD group compared with controls. Importantly, FA for the frontal and parietal lobes was negatively associated with the dialysis duration of ESRD patients, ALFF z-scores for the medial prefrontal cortex (MPFC) were positively correlated with the dialysis duration of ESRD patients and Serum calcium of ESRD patients negatively correlated with FA values in the frontal and parietal lobes (p<0.05).ConclusionOur study revealed that both impaired brain structure and function in ESRD patients with routine hemodialysis distributed mainly in the parietal, temporal, and frontal lobes. ESRD patients have cognitive impairment and declined memory ability. Serum calcium and dialysis duration might be associated with the impairment of brain structure and function in patients with ESRD.

Background and PurposeTemporomandibular disorders (TMD), especially pain-related TMD, are closely related to social and psychological factors. We aimed to measure changes in spontaneous brain activity and its related functional connectivity (FC), as well as FC characteristics within the mood-regulating circuits (MRC) in TMD patients by resting-state functional magnetic resonance imaging (RS-fMRI), and to analyze the relationship between these parameters and emotional symptoms.Materials and MethodsTwenty-one adult TMD patients and thirty demographically matched healthy controls (HCs) underwent clinical scale evaluation and RS-fMRI scanning. After processing RS-fMRI data, the values of the amplitude of low-frequency fluctuation (ALFF) between the two groups were compared. Regions with abnormal ALFF values were selected as areas of interest (ROIs) to compare the differences of whole-brain seed-based FC between groups. The FCs between regions within MRC were also analyzed and compared. In addition, the relationships between RS-fMRI characteristics and pain and mood were explored by correlation and mediation analyses.ResultsCompared with HCs, TMD patients showed increased ALFF in the right parahippocampal gyrus (PHG), the right supplementary motor area, and the bilateral precentral gyrus, with decreased ALFF in the right cerebelum_crus2. Patients showed enhanced right PHG-related FC in the vermis and posterior cingulate cortex, orbitofrontal cortex (OFC)-related FC in the striatal-frontal regions, while decreased dorsolateral prefrontal cortex-related FC in the amygdala. In TMD patients, ALFF values in the right PHG and FC values between the right PHG and the vermis were positively correlated with depressive symptoms. Abnormal FCs in the left striatal-orbitofrontal pathway were correlated with pain and depressive symptoms. More importantly, mediation analysis revealed that chronic pain mediates the relationship between FC of right PHG with vermis and depressive symptoms, and abnormal FC in the left striatal-orbitofrontal pathway can mediate the association between pain and depressive symptoms.ConclusionTMD patients have dysregulated spontaneous activity and FC in the default mode network, sensorimotor network and pain-related regions, as well as dysfunction of the fronto-striatal-limbic circuits. The development of negative emotions in TMD may be related to the dysfunction of components within the reward system (especially hippocampus complex, OFC, striatum) due to chronic pain.

BackgroundCerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) mainly manifests with cognitive impairment. Cognitive deficits in patients with CADASIL are correlated with structural brain changes such as lacunar lesion burden, normalized brain volume, and anterior thalamic radiation lesions, but changes in resting-state functional brain activity in patients with CADASIL have not been reported.MethodsThis study used resting-state functional magnetic resonance imaging (fMRI) to measure the amplitude of low-frequency fluctuation (ALFF) in 22 patients with CADASIL and 44 healthy matched controls. A seed-based functional connectivity (FC) analysis was used to investigate whether the dysfunctional areas identified by ALFF analysis exhibited abnormal FC with other brain areas. Pearson’s correlation analysis was used to detect correlations between the ALFF z-score of abnormal brain areas and clinical scores in patients with CADASIL.ResultsPatients with CADASIL exhibited significantly lower ALFF values in the right precuneus and cuneus (Pcu/CU) and higher ALFF values in the bilateral superior frontal gyrus (SFG) and left cerebellar anterior and posterior lobes compared with controls. Patients with CADASIL showed weaker FC between the areas with abnormal ALFF (using peaks in the left and right SFG and the right Pcu/CU) and other brain areas. Importantly, the ALFF z-scores for the left and right SFG were negatively associated with cognitive performance, including Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment scores (MoCA), respectively, whereas those of the right Pcu/CU were positively correlated with the MMSE score.ConclusionsThis preliminary study provides evidence for changes in ALFF of the right Pcu/CU, bilateral SFG and left cerebellar anterior and posterior lobes, and associations between ALFF values for abnormal brain areas and cognitive performance in patients with CADASIL. Therefore, spontaneous brain activity may be a novel imaging biomarker of cognitive impairment in this population.

The difference in spontaneous brain activity between acute subjective tinnitus patients (with or without hearing loss) and control participants was explored using the amplitude of low-frequency fluctuations and degree centrality methods through resting-state functional magnetic resonance imaging. The study aimed to provide an objective basis for clinical diagnosis and pathogenesis of patients with acute subjective tinnitus. Fourteen acute subjective tinnitus (AST) patients with hearing loss (AST-HL), 6 AST patients with no hearing loss (AST-NHL), and 14 healthy controls (HCs) with age, sex, and education status matched were recruited for this study. Resting-state functional magnetic resonance imaging (fMRI) examinations were performed in a resting state and the amplitude of low-frequency fluctuations (ALFF) and degree centrality (DC) values of each group were acquired. Statistical analysis was performed to assess the ALFF and DC values of different brain areas of the participants (AST-HL and AST-NHL were compared with HCs, but AST-HL and AST-NHL were not). Patients with acute subjective tinnitus and hearing loss showed a significantly increased amplitude of low-frequency fluctuation values in the left middle temporal gyrus and bilateral frontal gyrus/marginal lobe/cingulate gyrus but a decreased amplitude of low-frequency fluctuations values in the bilateral superior temporal gyrus/anterior cerebellar lobe in comparison with healthy controls. The amplitude of low-frequency fluctuation values of patients with acute subjective tinnitus and hearing loss in the right posterior lobe of the cerebellum, bilateral temporal gyrus, bilateral lenticular nucleus, bilateral frontal gyrus, right inferior occipital gyrus, were higher, but were significantly lower in the bilateral anterior lobe of cerebellum/superior temporal gyrus and left posterior cerebellar lobe as compared with those of healthy controls. Degree centrality values in the healthy controls group were increased in the right superior marginal gyrus and decreased in the right thalamus in patients with acute subjective tinnitus and hearing loss, while patients with acute subjective tinnitus with no hearing loss presented significantly higher degree centrality values in the left frontal lobe and lower degree centrality values in the left center rear return. Aberrant amplitude of low-frequency fluctuations and values exist in various brain regions, indicating abnormal spontaneous brain activity in both acute subjective tinnitus and hearing loss and acute subjective tinnitus no hearing loss patients. The pathogenesis of acute subjective tinnitus may be related to abnormalities in both the auditory cortex and nonauditory cortex. These findings provide more evidence to help clarify the neuronal symptoms of acute subjective tinnitus patients.