Changes in the hippocampal volume in chronic migraine, episodic migraine, and medication overuse headache patients.

Background and purpose:

Hippocampi are the structures located in the medial depths of both temporal lobes, mainly responsible for memory, navigation and regulation of emotions, and activated during the processing of pain and the modification of nociceptive stimuli. Chronic pain is thought to have stress-like detrimental modulatory effects on the hippocampal neurogenesis, and adults with chronic pain have been showed to have lower hippocampal volumes. The present study aims to show the relationship between headaches and hippocampal volume by comparing the right, left and total hippocampal volumes of patients with Episodic Migraine (EM), Chronic Migraine (CM) and Medication Overuse Headache (MOH) to those of the healthy control group using the Magnetic Resonance Imaging (MRI) technique, also by looking into the correlation between the number of painful days and attacks and the current hippocampal volumes.

A total of 30 patients (10 EM, 10 CM, 10 MOH) from 18 to 45 years of age diagnosed with migraine and also followed up by the neurology outpatient clinic from February to May 2022 and 30 healthy volunteers of similar ages and sexes to the patient group were included in the study. In addition to the routine cranial MRI protocols of all the participants, further cranial images were taken with the addition of the T1W 3D FSPGR sequence adjusted to the hippocampal body in the coronal plane and covering the whole brain. Hippocampal volumes were measured manually.

There were 27 females and 3 males in the patient group versus 28 females and 2 males in the control group, and no statistically significant differences in age and sex were found between the groups. The control group had higher average right, left and total hippocampal volumes than the whole patient group, but only the total hippocampal volume was significantly different between the groups. There was a negative correlation between the number of painful days and the measured right hippocampal and total hippocampal volumes; however, the measured values were not statistically significant. 

It was concluded that the changes in the hippocampal volume in migraine might be associated with the pain characteristics of the disorder. 

Gray matter alteration in medication overuse headache: a coordinates-based activation likelihood estimation meta-analysis.

Medication overuse headache (MOH) is a prevalent secondary headache, bringing heavy economic burden and neuropsychological damage. Neuroimaging studies on the disease reported divergent results. To merge the reported neuroimaging alterations in MOH patients and explore a pathophysiological mechanism of this disorder. A meta-analytic activation likelihood estimation (ALE) analysis method was used. We systematically searched English and Chinese databases for both morphological and functional neuroimaging studies published before Nov 18, 2021. Reported altered brain regions and the stereotactic coordinates of their peaks were extracted and pooled by GingerALE using Gaussian probability distribution into brain maps, illustrating converged regions of alteration among studies. We identified 927 articles, of which five studies on gray matter changes, using voxel-based morphometry (VBM) were eventually included for ALE analysis, with 344 subjects and 54 coordinates put into GingerALE. No functional magnetic resonance imaging (fMRI) or positron emission topography (PET) studies were included for pooling. Compared with healthy controls (HCs), MOH featured increased gray matter density in midbrain, striatum, cingulate, inferior parietal cortex and cerebellum (P < 0.001 uncorrected), whereas decreased gray matter density in orbitofrontal cortex (P < 0.05, family-wise error), frontal, insular and parietal cortices (P < 0.001 uncorrected). Withdrawal of analgesics led to decreased gray matter density in superior temporal gyrus, cuneus, midbrain and cerebellum (P < 0.001 uncorrected). This meta-analysis confirmed that medication overuse headache is associated with morphologic alteration in the reward system, the prefrontal cortex and a reversible modification in the pain network. Further functional imaging paradigms and longitudinal studies are required for a more definite conclusion and a causal mechanism.

Enhanced functional connectivity between habenula and salience network in medication-overuse headache complicating chronic migraine positions it within the addiction disorders: an ICA-based resting-state fMRI study.

BACKGROUND: Medication-overuse headache (MOH) is a relatively frequently occurring secondary headache caused by overuse of analgesics and/or acute migraine medications. It is believed that MOH is associated with dependence behaviors and substance addiction, in which the salience network (SN) and the habenula may play an important role. This study aims to investigate the resting-state (RS) functional connectivity between the habenula and the SN in patients with MOH complicating chronic migraine (CM) compared with those with episodic migraine (EM) and healthy controls (HC). METHODS: RS-fMRI and 3-dimensional T1-weighted images of 17 patients with MOH + CM, 18 patients with EM and 30 matched healthy HC were obtained. The RS-fMRI data were analyzed using the independent component analysis (ICA) method to investigate the group differences of functional connectivity between the habenula and the SN in three groups. Correlation analysis was performed thereafter with all clinical variables by Pearson correlation. RESULTS: Increased functional connectivity between bilateral habenula and SN was detected in patients with MOH + CM compared with patients with EM and HC respectively. Correlation analysis showed significant correlation between medication overuse duration and habenula-SN connectivity in MOH + CM patients. CONCLUSIONS: The current study supported MOH to be lying within a spectrum of dependence and addiction disorder. The enhanced functional connectivity of the habenula with SN may correlate to the development or chronification of MOH. Furthermore, the habenula may be an indicator or treatment target for MOH for its integrative role involved in multiple aspects of MOH.

Evaluation of structural changes in orbitofrontal cortex in relation to medication overuse in migraine patients: a diffusion tensor imaging study.

BACKGROUND: Migraine is a prevalent neurological disease that leads to severe headaches. Moreover, it is the commonest among the primary headaches that cause medication overuse headache (MOH). The orbitofrontal cortex (OFC) is one of the structures most associated with medication overuse. OBJECTIVE: To determine microstructural changes in the OFC among migraine patients who developed MOH, through the diffusion tensor imaging (DTI) technique. METHODS: Fifty-eight patients who had been diagnosed with migraine based on the Classification of Headache Disorders (ICHD-III-B) were included in the study. Patients were sub-classified into two groups, with and without MOH, based on the MOH criteria of ICHD-III-B. DTI was applied to each patient. The OFC fractional anisotropy (FA), and apparent diffusion coefficient (ADC) values of the two groups were compared. RESULTS: The mean age of all the patients was 35.98±7.92 years (range: 18-65), and 84.5% (n=49) of them were female. The two groups, with MOH (n=25) and without (n=33), were alike in terms of age, gender, family history, migraine with or without aura and duration of illness. It was found that there was a significant difference in FA values of the left OFC between the two groups (0.32±0.01 versus 0.29±0.01; p=0.04). CONCLUSIONS: An association was found between MOH and changes to OFC microstructure. Determination of neuropathology and factors associated with medication overuse among migraine patients is crucial in terms of identifying the at-risk patient population and improving proper treatment strategies specific to these patients.

Evaluation of structural changes in orbitofrontal cortex in relation to medication overuse in migraine patients: a diffusion tensor imaging study / Avaliação das mudanças estruturais no córtex orbitofrontal em relação ao uso excessivo de medicamentos em pacientes com migrânea: um estudo de imagem por tensor de difusão

Abstract Background: Migraine is a prevalent neurological disease that leads to severe headaches. Moreover, it is the commonest among the primary headaches that cause medication overuse headache (MOH). The orbitofrontal cortex (OFC) is one of the structures most associated with medication overuse. Objective: To determine microstructural changes in the OFC among migraine patients who developed MOH, through the diffusion tensor imaging (DTI) technique. Methods: Fifty-eight patients who had been diagnosed with migraine based on the Classification of Headache Disorders (ICHD-III-B) were included in the study. Patients were sub-classified into two groups, with and without MOH, based on the MOH criteria of ICHD-III-B. DTI was applied to each patient. The OFC fractional anisotropy (FA), and apparent diffusion coefficient (ADC) values of the two groups were compared. Results: The mean age of all the patients was 35.98±7.92 years (range: 18-65), and 84.5% (n=49) of them were female. The two groups, with MOH (n=25) and without (n=33), were alike in terms of age, gender, family history, migraine with or without aura and duration of illness. It was found that there was a significant difference in FA values of the left OFC between the two groups (0.32±0.01 versus 0.29±0.01; p=0.04). Conclusions: An association was found between MOH and changes to OFC microstructure. Determination of neuropathology and factors associated with medication overuse among migraine patients is crucial in terms of identifying the at-risk patient population and improving proper treatment strategies specific to these patients.

RESUMO Introdução: A migrânea é uma doença neurológica prevalente que causa fortes dores de cabeça. Além disso, é a mais comum entre as cefaleias primárias que causam cefaleia por uso excessivo de medicamentos (CUEM). O córtex orbitofrontal (OF) é uma das estruturas mais associadas ao uso excessivo de medicamentos. Objetivo: Determinar alterações microestruturais no córtex OF em pacientes com migrânea que desenvolveram CUEM, por meio da técnica de imagem por tensor de difusão (ITD). Métodos: Cinquenta e oito pacientes com diagnóstico de migrânea, com base na Classificação das Cefaleias (ICHD-III-B), foram incluídos no estudo. Os pacientes foram subclassificados em dois grupos, com e sem CUEM, com base nos critérios de CUEM da ICHD-III-B. A ITD foi aplicada a cada paciente. Os valores de anisotropia fracionada OFC (AF) e coeficiente de difusão aparente (CDA) dos dois grupos foram comparados. Resultados: A média de idade de todos os pacientes foi de 35,98±7,92 anos (variação: 18‒65), sendo 84,5% (n=49) do sexo feminino. Os dois grupos, com CUEM (n=25) e sem (n=33), são semelhantes em termos de idade, sexo, história familiar, migrânea com ou sem aura e duração da doença. Verificou-se que houve diferença significativa nos valores de AF do córtex OF esquerdo entre os dois grupos (0,32±0,01 versus 0,29±0,01; p=0,04). Conclusões: Foi encontrada associação entre o CUEM e as alterações na microestrutura do córtex OF. A determinação da neuropatologia e dos fatores associados ao uso excessivo de medicamentos entre pacientes com migrânea é crucial para identificar a população de pacientes em risco e melhorar as estratégias de tratamento adequadas específicas para esses pacientes.

Clinical and biobehavioral perspectives: Is medication overuse headache a behavior of dependence?

Medication overuse headache (MOH), previously known as analgesic abuse headache or medication misuse headaches, is a common form of chronic headache disorder that has a detrimental impact on health and society. Although it has been widely accepted that overusing abortive medications is paradoxically the cause of MOH and drug discontinuation is the treatment of choice, ongoing debates exist as to whether drug consumption per se is the cause or consequence of headache chronification. Certain features in MOH such as their compulsive drug-seeking behavior, withdrawal headaches and high relapse rates share similarities with drug dependence, suggesting that there might be common underlying biological and psychobehavioral mechanisms. In this regard, this article will discuss the updated evidence and current debates on the possible biobehavioral overlap between MOH and drug dependence. To begin with, we will discuss whether MOH has characteristics of substance dependence based on standard psychiatry diagnostic criteria and other widely used dependence scales. Recent epidemiological studies underscoring common psychiatric comorbidities between the two disorders will also be presented. Although both demonstrate seemingly distinct personality traits, recent studies revealed similar decision-making impairment from a cognitive perspective, indicating the presence of a maladaptive reward system in both disorders. In addition, emerging imaging studies also support this notion by showing reversible morphological and functional brain changes related to the mesocorticolimbic reward circuitry in MOH, with a strong resemblance to those in addiction. Finally, an increased familial risk for drug dependence and genetic association with dopaminergic and drug dependence molecular pathways in MOH also support a possible link between MOH and addiction. Understanding the role of dependence in MOH will have a great impact on disease management as this will provide the missing piece of the puzzle in current therapeutic strategies.

[Headache emergencies are easily overlooked]. / Kopfschmerzen als Notfall sind leicht übersehen.

This article presents secondary headache syndromes caused by life-threatening disease as well as symptomatic headaches requiring immediate treatment to prevent irreversible deficits. Clinical signs and symptoms indicating a secondary headache syndrome are summarized in the so-called SNOOP list (SNOOP: systemic symptoms, neurological symptoms, acute onset, older patients and previous history). The main topic of this publication is the diagnostic procedure, with a discussion of the pitfalls of computed tomography and magnetic resonance imaging investigations and the specificities of other methods such as lumbar puncture and duplex sonography.

Persistent post-traumatic headache: a migrainous loop or not? The clinical evidence.

BACKGROUND: Headache is a common complication of traumatic brain injury. The International Headache Society defines post-traumatic headache as a secondary headache attributed to trauma or injury to the head that develops within seven days following trauma. Acute post-traumatic headache resolves after 3 months, but persistent post-traumatic headache usually lasts much longer and accounts for 4% of all secondary headache disorders. MAIN BODY: The clinical features of post-traumatic headache after traumatic brain injury resemble various types of primary headaches and the most frequent are migraine-like or tension-type-like phenotypes. The neuroimaging studies that have compared persistent post-traumatic headache and migraine found different structural and functional brain changes, although migraine and post-traumatic headache may be clinically similar. Therapy of various clinical phenotypes of post-traumatic headache almost entirely mirrors the therapy of the corresponding primary headache and are currently based on expert opinion rather than scientific evidence. Pharmacologic therapies include both abortive and prophylactic agents with prophylaxis targeting comorbidities, especially impaired sleep and post-traumatic disorder. There are also effective options for non-pharmacologic therapy of post-traumatic headache, including cognitive-behavioral approaches, onabotulinum toxin injections, life-style considerations, etc. CONCLUSION: Notwithstanding some phenotypic similarities, persistent post-traumatic headache after traumatic brain injury, is considered a separate phenomenon from migraine but available data is inconclusive. High-quality studies are further required to investigate the pathophysiological mechanisms of this secondary headache, in order to identify new targets for treatment and to prevent disability.

Increased cerebral responses to salient transitions between alternating stimuli in chronic migraine with medication overuse headache and during migraine attacks.

INTRODUCTION: In a previous study exploring central pain modulation with heterotopic stimuli in healthy volunteers, we found that transitions between sustained noxious and innocuous thermal stimulations on the foot activated the "salience matrix". Knowing that central sensory processing is abnormal in migraine, we searched in the present study for possible abnormalities of these salient transitional responses in different forms of migraine and at different time points of the migraine cycle. METHODS: Participants of both sexes, mostly females, took part in a conditioned pain modulation experiment: Migraineurs between (n = 14) and during attacks (n = 5), chronic migraine patients with medication overuse headache (n = 7) and healthy volunteers (n = 24). To evoke the salience response, continuous noxious cold or innocuous warm stimulations were alternatively applied on the right foot. Cerebral blood oxygenation level dependent responses were recorded with fMRI. RESULTS: Switching between the two stimulations caused a significant transition response in the "salience matrix" in all subject groups (effect of the condition). Moreover, some group effects appeared on subsequent post-hoc analyses. Augmented transitional blood oxygenation level dependent responses in the motor cortex and superior temporal sulcus were found in two patient groups compared to healthy controls: chronic migraine with medication overuse headache patients and migraineurs recorded during an attack. In chronic migraine with medication overuse headache patients, salience-related responses were moreover greater in the premotor cortex, supplementary motor area, lingual gyrus and dorso-medial prefrontal cortex and other "salience matrix" areas, such as the anterior cingulate and primary somatosensory cortices. CONCLUSION: This study shows salience-related hyperactivation of affective and motor control areas in chronic migraine with medication overuse headache patients and, to a lesser extent, in episodic migraine patients during an attack. The greater extension of exaggerated blood oxygenation level dependent responses to unspecific salient stimuli in chronic migraine with medication overuse headache than during a migraine attack could be relevant for headache chronification.

White matter diffusion abnormalities in migraine and medication overuse headache: A 1.5-T tract-based spatial statistics study.

OBJECTIVES: Migraine and medication overuse headache are common, but its pathophysiology remains unclear. Differential diagnosis of chronic headache is still challenging. Conventional brain imaging techniques exclude secondary causes of headache but cannot produce a proper diagnosis. Accordingly, more sensitive diagnostic methods are needed for certain diagnosis. In the present study, we performed voxel-wise tract-based spatial statistics of 1.5-T diffusion tensor imaging in migraine patients and healthy volunteers. PATIENTS AND METHODS: One hundred and three migraine patents and 46 healthy volunteers were registered. The fractional anisotropy values in the white matter of each group compared to age-matched healthy volunteers. RESULTS: Compared to the controls, the migraine without aura with medication overuse headache had remarkable fractional anisotropy decrease in the white matter in several regions. The migraine with aura without medication overuse headache also had significant fractional anisotropy decrease compared to the controls. The disease duration and frequency of migraine attack were not correlated with fractional anisotropy values of the corpus callosum. CONCLUSION: Our 1.5-T DTI study demonstrated significantly lower fractional anisotropy in the white matter in the MoA with medication overuse headache and MwA without medication overuse headache groups, suggesting that fractional anisotropy abnormalities may be useful biomarkers in headache patients.

Secondary Headaches in Children and Adolescents: What Not to Miss.

INTRODUCTION: Headaches are a common occurrence in childhood and adolescence. Most children presenting with a chief complaint of headache have a self-limited infectious disorder or primary headache syndrome that should not require extensive workup. PURPOSE OF REVIEW: Differentiating these conditions from other more serious causes of headache in children can sometimes be difficult. This article aims to provide information regarding "red flags" that should indicate a need for concern for disorders that require more urgent evaluation. RECENT FINDINGS: Long-held beliefs about specific "red flags" that have been analyzed in recent years as to their validity and new criteria for the diagnosis of idiopathic intracranial hypertension have been elaborated based on study. These publications are reviewed in this article. Knowledge of past and current literature on secondary headache in children, combined with thorough history taking and examination, should help determine when there is concern for a serious secondary cause for headache in children and adolescents and direct workup.

Resting State Functional Connectivity After Sphenopalatine Ganglion Blocks in Chronic Migraine With Medication Overuse Headache: A Pilot Longitudinal fMRI Study.

OBJECTIVE: In this pilot study, the purpose is to investigate if a series of sphenopalatine ganglion (SPG) blockade treatments modulate the functional connectivity within the salience and central executive network (CEN) in chronic migraine with medication overuse headaches (CMw/MOH ). BACKGROUND: Using intranasal local anesthesia to block the SPG for the treatment of various headache disorders has been employed in clinical practice since the early 1900s. However, the exact mechanism of how SPG modulate resting state intrinsic functional brain networks connectivity remains to be elucidated. This pilot study seeks to understand the resting state connectivity changes in salience and CENs, with emphasis on the mesocorticolimbic systems, before and after a series of SPG block treatments. METHODS: Using fMRI, resting state connectivity was derived from predefined networks of nodes (regions of interests) for the salience (27 nodes, 351 connections) and CENs (17 nodes, 136 connections). After treatments, a paired samples t-test (with 10,000 permutations to correct for multiple comparison) was used to evaluate changes in the intranetwork resting state functional connectivity within the salience and executive networks, as well as the overall network connectivity strength. RESULTS: When comparing connectivity strength at baseline to that at the end of treatment in our cohort of 10 CMw/MOH participants, there were several connections within the salience (n = 9) and executive (n = 8) networks that were significantly improved. Within the salience network, improved connectivity was observed between the prefrontal cortex and various regions of the insula, basal ganglia, motor, and frontal cortex. Additionally, changes in connectivity were observed between regions of the temporal cortex with the basal ganglia and supramarginal gyrus. Within the CEN, improved connectivity was observed between the prefrontal cortex and regions of the anterior thalamus, caudate, and frontal cortex. After treatment, the overall CEN connectivity was significantly improved (Baseline 0.00 ± 0.08; 6 weeks 0.03 ± 0.09, P = .01); however, the overall salience network connectivity was not significantly improved (Baseline -0.01 ± 0.10; 6 weeks 0.01 ± 0.12, P = .26). Additionally, after treatment, there was a significant reduction in the number of moderate/severe headache days per month (Baseline 21.1 ± 6.6; 6 weeks 11.2 ± 6.5, P < .001), HIT-6 (Baseline 66.1 ± 2.6; 6 weeks 60.2 ± 3.6, P < .001), and PHQ-9 (Baseline 12.4 ± 5.7; 6 weeks 6.1 ± 3.6, P = .008) scores. CONCLUSION: In this longitudinal fMRI study, we observed improved functional connectivity within both networks, primarily involving connectivity between regions of the prefrontal cortex and limbic (cortical-limbic) structures, and between different cortical (cortical-cortical) regions after a series of repetitive SPG blockades. The overall CEN strength was also improved. Our results suggest that recurrent parasympathetic inhibition via SPG is associated with improved functional connectivity in brain regions critical to pain processing in CMw/MOH .

[Altered Brainstem Volume in Medication-overuse Headache: A Pilot Magnetic Resonance Imaging Evaluation].

Objective To investigate the altered brainstem volume in patients with medication-overuse headache(MOH). Methods The high-resolution structural images were obtained from 36 MOH patients and 32 normal controls(NC).The brainstem was segmented into midbrain,pons,and medulla,whose volume were measured respectively.Results There was a significantly smaller midbrain volume in MOH patients [(5.80±0.53) ml] than that in NC [(6.14±0.67)ml](t=2.36,P=0.02).The volumes of pons,medulla,and whole brainstem showed no significant difference in MOH patients [(13.13±1.42)ml,(4.55±0.51)ml,and(23.48±2.23)ml,respectively] compared with those in NC [(13.67±1.61) ml,(4.66±0.44) ml,and(24.47±2.56) ml,respectively](tpons=1.47,Ppons=0.15;tmedulla=0.93,Pmedulla=0.35;and tbrainstem=1.71,Pbrainstem=0.09,respectively).Conclusion A smaller midbrain volume may be one of the specific features of pain pathway in MOH,and the automated brainstem subfield segmentation and volumetry may be useful tools for evaluating brainstem alternation in MOH patients.

Lower hippocampal subfields volume in relation to anxiety in medication-overuse headache.

Background Hippocampus (HIP) was an important limbic structure, and concurrent emotion disorders may occur in medication-overuse headache patients. The aim of this study is to investigate altered HIP and HIP subfields volume in relation with the anxiety in medication-overuse headache patients using a state-of-the-art hippocampal segment method. Results The current study presented that a significant lower HIP and HIP subfields volume were identified in medication-overuse headache compared with that in normal controls except right HIP tail, bilateral parasubiculums, and HIP fissure. The left HIP and right subiculum presented negative correlation with headache variables, and the right subiculum, Cornu Ammonis 4, granule cell layer of dentate gyrus, bilateral Cornu Ammonis 1, molecular layer, and whole HIP presented negative correlation with Hamilton Anxiety Scale score, which were further confirmed by the linear regression analysis with the exclusion of psychological variables and headache variables, respectively. Conclusions The lower HIP and HIP subfields volume were identified in medication-overuse headache patients, and negatively related with anxiety condition. The potential mechanism for the comorbidity medication-overuse headache and anxiety might be interpreted as the reciprocal causation relationship and co-occurrence relationship.

Longitudinal assessment of gray matter volumes and white matter integrity in patients with medication-overuse headache.

Background Medication-overuse headache is a common clinical entity, but neuroimaging studies investigating volumetric and microstructural alterations of the brain in medication-overuse headache are rare. Therefore, in the current longitidunal study we evaluated gray matter volume and white matter integrity in patients with medication-overuse headache before and after drug withdrawal. Methods A prospective study evaluated 27 patients with medication-overuse headache and 27 age-, sex-, and education-matched healthy adults. High-resolution T1-weighted magnetic resonance imaging and diffusion tensor imaging were obtained from the control group and medication-overuse headache patients before and six months after drug withdrawal. Tract-based spatial statistics of multiple diffusivity indices and voxel-based morphometry were employed to investigate white and gray matter abnormalities. Results No correlation was found between age, gender, education and smoking status in both groups. The most commonly overused medications were simple analgesics (96.3%) and combined analgesics (3.7%). The mean duration of the history of medication overuse and headaches was 56.7 ± 63.5 months. White matter diffusional and gray matter morphological alterations including volume, fractional anisotropy, radial diffusivity, and axial diffusivity analyses showed no significant relationship in the patients before and six months after withdrawal of analgesics. Also no difference was observed between the patients versus controls. Conclusion Our data demonstrated no structural alterations within the brain in medication-overuse headache.

Neuroimaging Findings in Patients with Medication Overuse Headache.

Medication overuse headache (MOH) is a secondary headache syndrome defined as the deterioration of the headache associated with the overuse of analgesics. The prevalence of MOH is 1-2% in the general population and even up to 50% in special clinics. Overuse of abortive medications is highly associated with chronic daily headaches and also a known risk factor for headache evolution. Possible mechanisms include neural plasticity changes such as sensitization and defective endogenous pain inhibition. Psychological studies have suggested dependence, even addiction, in patients with MOH. Neuroimaging studies have provided valuable information concerning MOH pathophysiology. Magnetic resonance imaging analyzed by voxel-based morphometry showed gray matter volume changes in brain areas participating the pain modulations. Changes of brain function at similar areas have been revealed by positron emission tomography and functional magnetic resonance imaging studies. Many of these changes were correlated with either headache and/or analgesics parameters such as frequency and duration. These changes are typically reversible after successful treatment. Though the cause or consequence debate remains unsettled, we are more in favor of these findings as maladaptive changes to the frequent headaches or medication overuse. Of these brain areas involved in MOH, orbitofrontal cortex is of interest in several ways. In an early positron emission tomography study, the hypometabolism persists after successful treatment which implied a causal role. The following morphological studies showed the orbitofrontal cortex volume could predict treatment responses. Functional magnetic resonance imaging studies, task positive and also resting-state ones, also reported changes within the mesocorticolimbic dopamine system, also known as reward system. Important brain areas of this system include ventral tegmental area, striatum, and orbitofrontal cortex. The system plays an important role in decision-making, dependence, and addiction, as implicated in psychological studies of MOH. Further studies on neuromodulation of this system may be considered in the treatment of MOH.

Modulation of salience network intranetwork resting state functional connectivity in women with chronic migraine.

Objective To investigate the intranetwork resting state fMRI connectivity within the Salience Network of chronic migraine with and without medication overuse headache. Methods We compared 351 pairs of intranetwork connectivity in chronic migraine (n = 13) and chronic migraine with medication overuse headache (n = 16) compared to matched controls, and between each chronic migraine subgroup. Results Compared to controls, 17 pairs of intranetwork connections in chronic migraine and 27 pairs in chronic migraine with medication overuse headache were decreased. When comparing chronic migraine with medication overuse headache versus chronic migraine, connectivity between bilateral extended amygdala, and between paracingulate to right ventral tegmental area/substantia nigra were decreased in chronic migraine (chronic migraine < chronic migraine with medication overuse headache). Connectivity between left dorsolateral prefrontal cortex to bilateral ventral striatum/pallidum, to bilateral dorsal anterior cingulate cortex; left anterior prefrontal cortex to contralateral orbitofrontal insula; and left ventral striatum/pallidum to ipsilateral supplementary motor area (SMA)/preSMA were decreased in chronic migraine with medication overuse headache (chronic migraine with medication overuse headache < chronic migraine). Conclusion Both chronic migraine subgroups had shared intranetwork connectivity abnormality, however, each subgroup had unique pattern of disruption within the salience network. The results suggest that the aberrant assignment of salience to external and internal stimuli plays an important role in chronic migraine and chronic migraine with medication overuse headache interictally, mostly involving mesolimbic pathways (especially bilateral extended amygdala) in chronic migraine, and prefrontal-subcortical limbic pathways in chronic migraine with medication overuse headache.

Alteration of gray matter texture features over the whole brain in medication-overuse headache using a 3-dimentional texture analysis.

BACKGROUND: Imaging studies have provided valuable information in understanding the headache neuromechanism for medication-overuse headache (MOH), and the aim of this study is to investigate altered texture features of MR structural images over the whole brain in MOH using a 3-dimentional texture analysis. METHODS: Brain three-dimensional T1-weighted structural images were obtained from 44 MOH patients and 32 normal controls (NC). The imaging processing included two steps: gray matter (gray images) segment and a 3-dimensional texture features mapping. Voxel-based gray-level co-occurrence matrix (VGLCM) was performed to measure the texture parameters mapping including Contrast, Correlation, Energy, Entropy and inverse difference moment (IDM). RESULTS: The texture parameters of increased Contrast and Entropy, decreased Energy and IDM were identified in cerebellar vermis of MOH patients compared to NCs. Increased Contrast and decreased Energy were found in left cerebellum. Increased Correlation located in left dorsolateral periaqueductal gray (L-dlPAG), right parahippocampal gyrus (R-PHG), and left middle frontal gyrus (L-MFG) and decreased Correlation located in right superior parietal lobule(R-SPL). Disease duration was positively correlated with Contrast of vermis and negatively correlated with Correlation of R-SPL.HAMD score was negatively correlated with Correlation of R-PHG. MoCA score was positively correlated with Correlation of R-SPL. CONCLUSION: The altered textures in gray matter related to pain discrimination and modulation, affective and cognitive processing were helpful in understanding the pathogenesis of MOH. Texture analysis using VGLCM is a sensitive and efficient method to detect subtle gray matter changes in MOH.

Volumetric abnormalities of thalamic subnuclei in medication-overuse headache.

BACKGROUND: The thalamus exerts a pivotal role in pain processing and cortical excitability control and a previous voxel-based morphometry study confirmed increased volume in bilateral thalamus in medication-overuse headache (MOH). The aim of this study is to investigate altered thalamic subnuclei volume in MOH compared with normal controls, and to evaluate the relationship of each thalamic subnuclei volume with the clinical variables. METHODS: High resolution three-dimensional T1-weighted fast spoiled gradient recalled echo MR images were obtained from 27 patients with MOH and 27 normal controls (NC). Thalamic subnuclei templates were created based on Talairach template with MNI space transformation, and the individual thalamic subnuclei templates were generated by applying the deformation field from structural image segment to the thalamic subnuclei templates, and then individual thalamci subnuclei volume were calculated. RESULTS: The whole thalamus and each thalamic subnuclei presented increased volume compared with NC (P < 0.05). The correlation analysis demonstrated that the whole thalamus volume and each thalamic subnuclei volume showed a negative relationship with HAMD scores(P < 0.05), and no any correlation with HAMA, VAS score and disease duration (P > 0.05). CONCLUSION: Increased gray matter volume in the whole thalamus and all the thalamus subnuclei may reflect central sensitization and higher-order of pain alteration in MOH. These structural changes in the thalamus may also be influenced by mood disturbances related to the MOH.