Neurophysiological tests and neuroimaging procedures in non-acute headache (2nd edition)

EEG Changes in Migraine-Can EEG Help to Monitor Attack Susceptibility?

Migraine is a highly prevalent brain condition with paroxysmal changes in brain excitability believed to contribute to the initiation of an attack. The attacks and their unpredictability have a major impact on the lives of patients. Clinical management is hampered by a lack of reliable predictors for upcoming attacks, which may help in understanding pathophysiological mechanisms to identify new treatment targets that may be positioned between the acute and preventive possibilities that are currently available. So far, a large range of studies using conventional hospital-based EEG recordings have provided contradictory results, with indications of both cortical hyper- as well as hypo-excitability. These heterogeneous findings may largely be because most studies were cross-sectional in design, providing only a snapshot in time of a patient's brain state without capturing day-to-day fluctuations. The scope of this narrative review is to (i) reflect on current knowledge on EEG changes in the context of migraine, the attack cycle, and underlying pathophysiology; (ii) consider the effects of migraine treatment on EEG features; (iii) outline challenges and opportunities in using EEG for monitoring attack susceptibility; and (iv) discuss future applications of EEG in home-based settings.

European Academy of Neurology guidelines on the treatment of cluster headache

BACKGROUND AND PURPOSE

Cluster headache is a relatively rare, disabling primary headache disorder with a major impact on patients' quality of life. This work presents evidence-based recommendations for the treatment of cluster headache derived from a systematic review of the literature and consensus among a panel of experts.

METHODS

The databases PubMed (Medline), Science Citation Index, and Cochrane Library were screened for studies on the efficacy of interventions (last access July 2022). The findings in these studies were evaluated according to the recommendations of the European Academy of Neurology, and the level of evidence was established using GRADE (Grading of Recommendations Assessment, Development, and Evaluation).

RECOMMENDATIONS

For the acute treatment of cluster headache attacks, there is a strong recommendation for oxygen (100%) with a flow of at least 12 L/min over 15 min and 6 mg subcutaneous sumatriptan. Prophylaxis of cluster headache attacks with verapamil at a daily dose of at least 240 mg (maximum dose depends on efficacy and tolerability) is recommended. Corticosteroids are efficacious in cluster headache. To reach an effect, the use of at least 100 mg prednisone (or equivalent corticosteroid) given orally or at up to 500 mg iv per day over 5 days is recommended. Lithium, topiramate, and galcanezumab (only for episodic cluster headache) are recommended as alternative treatments. Noninvasive vagus nerve stimulation is efficacious in episodic but not chronic cluster headache. Greater occipital nerve block is recommended, but electrical stimulation of the greater occipital nerve is not recommended due to the side effect profile.

What has neurophysiology revealed about migraine and chronic migraine?

Since the first electroencephalographic recordings obtained by Golla and Winter in 1959, researchers have used a variety of neurophysiological techniques to determine the mechanisms underlying recurrent migraine attacks. Neurophysiological methods have shown that the brain during the interictal phase of an episodic migraine is characterized by a general hyperresponsiveness to sensory stimuli, a malfunction of the monoaminergic brainstem circuits, and by functional alterations of the thalamus and thalamocortical loop. All of these alterations vary plastically during the phases of the migraine cycle and interictally with the days following the attack. Both episodic migraineurs recorded during an attack and chronic migraineurs are characterized by a general increase in the cortical amplitude response to peripheral sensory stimuli; this is an electrophysiological hallmark of a central sensitization process that is further reinforced through medication overuse. Considering the large-scale functional involvement and the main roles played by the brainstem-thalamo-cortical network in selection, elaboration, and learning of relevant sensory information, future research should move from searching for one specific primary site of dysfunction at the macroscopic level, to the chronic, probably genetically determined, molecular dysfunctions at the synaptic level, responsible for short- and long-term learning mechanisms.

Neuroimaging of Headache: Indications and Controversies

Headache is a common presenting symptom in the ambulatory setting that often prompts imaging. The increased use and associated health care money spent in the setting of headache have raised questions about the cost-effectiveness of neuroimaging in this setting. Neuroimaging for headache in most cases is unlikely to reveal significant abnormality or impact patient management. In this article, reasons behind an observed increase in neuroimaging and its impact on health care expenditures are discussed. The typical imaging modalities available and various imaging guidelines for common clinical headache scenarios are presented, including recommendations from the American College of Radiology.

Headache neuroimaging: A survey of current practice, barriers, and facilitators to optimal use

OBJECTIVE

The objective of this study was to understand current practice, clinician understanding, attitudes, barriers, and facilitators to optimal headache neuroimaging practices.

BACKGROUND

Headaches are common in adults, and neuroimaging for these patients is common, costly, and increasing. Although guidelines recommend against routine headache neuroimaging in low-risk scenarios, guideline-discordant neuroimaging is still frequently performed.

METHODS

We administered a 60-item survey to headache clinicians at the Veterans Affairs health system to assess clinician understanding and attitudes on headache neuroimaging and to determine neuroimaging practice patterns for three scenarios describing hypothetical patients with headaches. Descriptive statistics were used to summarize responses, stratified by clinician type (physicians or advanced practice clinicians [APCs]) and specialty (neurology or primary care).

RESULTS

The survey was successfully completed by 431 of 1426 clinicians (30.2% response rate). Overall, 317 of 429 (73.9%) believed neuroimaging was overused for patients with headaches. However, clinicians would utilize neuroimaging a mean (SD) 30.9% (31.7) of the time in a low-risk scenario without red flags, and a mean 67.1% (31.9) of the time in the presence of minor red flags. Clinicians had stronger beliefs in the potential benefits (268/429, 62.5%) of neuroimaging compared to harms (181/429, 42.2%) and more clinicians were bothered by harms stemming from the omission of neuroimaging (377/426, 88.5%) compared to commission (329/424, 77.6%). Additionally, APCs utilized neuroimaging more frequently than physicians and were more receptive to potential interventions to improve neuroimaging utilization.

CONCLUSIONS

Although a majority of clinicians believed neuroimaging was overused for patients with headaches, many would utilize neuroimaging in low-risk scenarios with a small probability of changing management. Future studies are needed to define the role of currently used red flags given their importance in neuroimaging decisions. Importantly, APCs may be an ideal target for future optimization efforts.

Diagnosis and management of migraine in ten steps

Migraine is a disabling primary headache disorder that directly affects more than one billion people worldwide. Despite its widespread prevalence, migraine remains under-diagnosed and under-treated. To support clinical decision-making, we convened a European panel of experts to develop a ten-step approach to the diagnosis and management of migraine. Each step was established by expert consensus and supported by a review of current literature, and the Consensus Statement is endorsed by the European Headache Federation and the European Academy of Neurology. In this Consensus Statement, we introduce typical clinical features, diagnostic criteria and differential diagnoses of migraine. We then emphasize the value of patient centricity and patient education to ensure treatment adherence and satisfaction with care provision. Further, we outline best practices for acute and preventive treatment of migraine in various patient populations, including adults, children and adolescents, pregnant and breastfeeding women, and older people. In addition, we provide recommendations for evaluating treatment response and managing treatment failure. Lastly, we discuss the management of complications and comorbidities as well as the importance of planning long-term follow-up.

ACR Appropriateness Criteria® Headache

Headache is one of the most common human afflictions. In most cases, headaches are benign and idiopathic, and resolve spontaneously or with minor therapeutic measures. Imaging is not required for many types of headaches. However, patients presenting with headaches in the setting of "red flags" such as head trauma, cancer, immunocompromised state, pregnancy, patients 50 years or older, related to activity or position, or with a corresponding neurological deficit, may benefit from CT, MRI, or noninvasive vascular imaging to identify a treatable cause. This publication addresses the initial imaging strategies for headaches associated with the following features: severe and sudden onset, optic disc edema, "red flags," migraine or tension-type, trigeminal autonomic origin, and chronic headaches with and without new or progressive features. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Factors Associated with Incidental Neuroimaging Abnormalities in New Primary Headache Patients

Background and Purpose

Deciding whether or not to perform neuroimaging in primary headache is a dilemma for headache physicians. The aim of this study was to identify clinical predictors of incidental neuroimaging abnormalities in new patients with primary headache disorders.

Methods

This cross-sectional study was based on a prospective multicenter headache registry, and it classified 1,627 consecutive first-visit headache patients according to the third edition (beta version) of the International Classification of Headache Disorders (ICHD-3β). Primary headache patients who underwent neuroimaging were finally enrolled in the analysis. Serious intracranial pathology was defined as serious neuroimaging abnormalities with a high degree of medical urgency. Univariable and multivariable logistic regression analyses were conducted to identify factors associated with incidental neuroimaging abnormalities.

Results

Neuroimaging abnormalities were present in 170 (18.3%) of 927 eligible patients. In multivariable analysis, age ≥40 years [multivariable-adjusted odds ratio (aOR)=3.37, 95% CI=2.07–6.83], male sex (aOR=1.61, 95% CI=1.12–2.32), and age ≥50 years at headache onset (aOR=1.86, 95% CI=1.24–2.78) were associated with neuroimaging abnormalities. In univariable analyses, age ≥40 years was the only independent variable associated with serious neuroimaging abnormalities (OR=3.37, 95% CI=1.17–9.66), which were found in 34 patients (3.6%). These associations did not change after further adjustment for neuroimaging modality.

Conclusions

Incidental neuroimaging abnormalities were common and varied in a primary headache diagnosis. A small proportion of the patients incidentally had serious neuroimaging abnormalities, and they were predicted by age ≥40 years. These findings can be used to guide the performing of neuroimaging in primary headache disorders.

Diagnostic Neuroimaging in Headache Patients: A Systematic Review and Meta-Analysis

OBJECTIVE

Neuroimaging in headache patients identifies clinically significant neurological abnormalities and plays an important role in excluding secondary headache diagnoses. We performed a systematic review and meta-analysis of the existing guidelines and studies surrounding neuroimaging in headache patients.

METHODS

The research question involved determining the prevalence of detecting clinically significant neurological abnormalities using neuroimaging in patients suspected of primary headache. Searches of the PubMed and Embase databases were conducted on English-language studies published from 1991 to 2016, and the reference lists of the retrieved articles were also checked manually. All headache subtypes and patients aged ≥15 years were included in the analysis.

RESULTS

Ten studies met the selection criteria. The pooled prevalence of detecting clinically significant abnormalities in the neuroimaging of headache patients was 8.86% (95% confidence interval: 5.12-15.33%). Subsequently, diverse subgroup analyses were performed based on the detection method, headache type, study type, study region, age group, and disease type.

CONCLUSION

The present findings indicate that limited neuroimaging methods should be carefully considered for headache diagnostic purposes when there are red flag symptoms. Limitations and suggested directions for future studies on neuroimaging in headache patients are described.

Neuroimaging of Adults with Headache: Appropriateness, Utilization, and an Economical Overview

One of the most common reasons that a patient seeks out a health care provider for a neuroscience-related issue is headache. Not all patients can, or probably should, be imaged with headache. We must use an approach that attends to scientific evidence, accepted guidelines, and available resources. This approach should focus on quality, safety, appropriateness, and utilization. This article reviews and discusses the consideration of imaging adult patients with headache.

Comparison of CPG's for the diagnosis, prognosis and management of non-specific neck pain: a systematic review

BACKGROUND

Neck pain (NP) is a very common musculoskeletal condition with potential for a high burden in disability and length of disorder. Clinical practice guidelines (CPG) give recommendations to clinicians for providing optimal care for patients however best practice recommendations are often contradictory. The purpose for this review was to conduct a SR of CPGs to assess the management recommendations for NP (diagnosis, treatment, prognosis, imaging).

METHODS

Standard SR methodology was employed including a grey literature search (including the National Guideline Clearing House). Medline, Cinahl, Embase, ILC, Cochrane, Central, and Lilacs were searched from 1995-to March 2018. Two raters evaluated all citations and a third rater resolved any disagreements. The AGREE II was used to assess risk of bias of each CPG. Data was extracted and included CPG purpose, type of NP problem and clinical recommendations. The AGREE II critical appraisal tool was used to assess risk of bias of each CPG.

RESULTS

From 640 articles, 241 were available for screening. A total of 46 guidelines were selected. CPG's were categorized by the NP population (General NP, whiplash, interventional, headache and risk for vertebral insufficiency) and type of clinical aim (diagnosis, prognosis, treatment, imaging). Each clinical NP population had a large overlap of clinical aims presented. The CPGs were directed to a variety of clinicians that included physicians, physiotherapists and chiropractors. Results suggest heterogeneity in CPG recommendations within each clinical aim. CPG characteristics accounting for these differences are outlined.

CONCLUSION

The majority of CPGs were developed for general NP that focused on treatment recommendations, with fewer number aimed at recommendations for diagnosis, prognosis, and outcomes. Heterogeneity of recommendations within the categories were noted as were potential factors associated with these differences, including CPG quality as assessed by the AGREE II.

"Worst Headache of Life" in a Migraineur: Marginal Value of Emergency Department CT Scanning

PURPOSE

The ACR Appropriateness Criteria recommend performing noncontrast head CT (NCCT) for patients with sudden severe headache ("worst headache of life" [WHOL] or "thunderclap headache" [TCH]). The aim of this study was to assess the value of NCCT scanning in patients with known migraine histories and WHOL or TCH. The hypothesis was that there would be little utility in performing emergency department (ED) NCCT scans in migraineurs without other red flags, even if they had WHOL or TCH.

METHODS

The ED NCCT scans of all patients reporting WHOL or TCH who had established diagnoses of migraine were retrospectively reviewed over a 5-year period. Patients without known intracranial pathology, cancer, or immunocompromising disease or recent head trauma were included as the main study group. For comparison, patients with any of those factors were included as the comparison group. Scans were graded as (1) normal, (2) minor unimportant findings, (3) findings requiring intervention or follow-up, or (4) critical.

RESULTS

Two hundred twenty-four patients with the chief symptom of WHOL or TCH and a history of migraine who underwent ED NCCT were studied. In the main study group, no patients had grade 4 imaging findings (0%), one had a false-positive grade 3 finding (0.8%), and there were no cases of subarachnoid hemorrhage (0%). In the comparison group, six patients had grade 4 imaging findings (6.5%) and three had grade 3 findings (3.3%).

CONCLUSIONS

NCCT in known migraineurs with WHOL or TCH who do not have intracranial pathology, cancer, immunocompromising disease, or recent head trauma yielded no critical findings. Therefore, the value of scanning these patients is questionable.

Electrophysiological Characteristics of the Migraine Brain: Current Knowledge and Perspectives

BACKGROUND

Despite pain being its most prominent feature, migraine is primarily a disorder of sensory processing. Electrophysiology-based research in the field has consistently developed over the last fifty years.

OBJECTIVE

To summarize the current knowledge on the electrophysiological characteristics of the migraine brain, and discuss perspectives.

METHODS

We critically reviewed the literature on the topic to present and discuss articles selected on the basis of their significance and/or novelty.

RESULTS

Physiologic fluctuations within time, between-subject differences, and methodological issues account as major limitations of electrophysiological research in migraine. Nonetheless, several abnormalities revealed through different approaches have been described in the literature. Altogether, these results are compatible with an abnormal state of sensory processing.

PERSPECTIVES

The greatest contribution of electrophysiological testing in the future will most probably be the characterization of sub-groups of migraine patients sharing specific electrophysiological traits. This should serve as strategy towards personalized migraine treatment. Incorporation of novel methods of analysis would be worthwhile.

Cluster headache

Cluster headache is an excruciating, strictly one-sided pain syndrome with attacks that last between 15 minutes and 180 minutes and that are accompanied by marked ipsilateral cranial autonomic symptoms, such as lacrimation and conjunctival injection. The pain is so severe that female patients describe each attack as worse than childbirth. The past decade has seen remarkable progress in the understanding of the pathophysiological background of cluster headache and has implicated the brain, particularly the hypothalamus, as the generator of both the pain and the autonomic symptoms. Anatomical connections between the hypothalamus and the trigeminovascular system, as well as the parasympathetic nervous system, have also been implicated in cluster headache pathophysiology. The diagnosis of cluster headache involves excluding other primary headaches and secondary headaches and is based primarily on the patient's symptoms. Remarkable progress has been achieved in developing effective treatment options for single cluster attacks and in developing preventive measures, which include pharmacological therapies and neuromodulation.

Determinants of Computed Tomography Head Scan Ordering for Patients with Low-Risk Headache in the Emergency Department

Background Many specialty societies have found that neuroimaging in headache is a low-value intervention for benign presentations. This study describes factors that influence Emergency Room (ER) physicians' adherence to Choosing Wisely (CW) recommendations for low-risk headache patients presenting to Calgary's Emergency Departments (EDs). Emergency medicine has yet to address imaging in headache as a CW topic; however, this study may inform that decision. Methods Data were retrospectively collected for all patients presenting to Calgary EDs with headaches from April 1, 2014 to March 31, 2016. Patients were deemed low-risk by virtue of discharge home from the ED, age < 50, and no lumbar puncture (LP), trauma, neurology, or neurosurgery consult or red flags on history. The primary outcome was computed tomography (CT) ordering rates with an eye to medical doctor (MD) practice variation. Patient, physician, and environmental factors were analyzed to compare patients who did and did not receive a CT. Results Two thousand seven hundred and thirty-four headache patients met the eligibility criteria. A total of 117 Calgary ER physicians were included, all of whom had seen 10 or more headache patients over the study period. Physician practice variation was vast, with a mean ordering rate of 38.0% and a range of 0% to 95% (M = 39.0%, IQR = 21.0%). CTs were ordered more often in males than females (39.9%; 34.1%; p = 0.002) and in patients presenting during the day and evening (38.1%; 39.0%) compared to the night (29.7%; p < 0.001). Patients were divided into quartiles by age, with the oldest group (41.6 - 50 years) receiving significantly more head CTs (45.1%) than the other quartiles (34.9%; 34.9%; 27.5%; p < 0.001). Longer triage-to-discharge times were associated with an increase in CT ordering rates (12% for < 2.95 hours; 35% for > 4 hour wait; p < 0.001). Lastly, patients who did not have a CT were more likely to revisit the ED within seven days compared to those who did (6.9% vs 4.0%; p = 0.003), but their seven-day admission rate was unaffected (0.6% in the group that got CTs and 0.3% in the group that did not get a CT). Time to assessment, the day of the week, physician gender, years of experience, and training program did not influence CT ordering practices. Conclusion To our knowledge, this is the first study to assess how patient, physician, and environmental factors relate to the use of CT scans in low-risk headaches presenting to the ED. CW guidelines are not optimally adhered to, and the findings in this study findings may inspire new ideas for maximizing the judicious use of healthcare resources.

Visual and auditory cortical evoked potentials in interictal episodic migraine: An audit on 624 patients from three centres

Background

Many studies report a habituation deficit of visual evoked potentials (VEP) and/or increased intensity dependence of auditory evoked cortical potentials (IDAP) in episodic migraine patients between attacks. These findings have a pathophysiological interest, but their diagnostic utility is not known.

Aims

To perform an audit on a large database of interictal VEP and IDAP recordings in episodic migraine patients and evaluate their diagnostic accuracy.

Methods

We pooled data for VEP habituation and IDAP measured in 624 episodic migraineurs (EM) and 360 healthy volunteers (HV) from three centers. Thresholds were calculated by Receiver Operating Curve analysis and used to calculate sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-) and the accuracy of each test, using ICHD diagnostic criteria as the gold standard.

Results

In EM, VEP habituation was significantly lower than in HV, and IDAP slopes were significantly steeper. VEP (five blocks of 50 responses), VEP (six blocks of 100 responses) and IDAP had respectively 61.0%, 61.4% and 45.7% sensitivity, and 77.9%, 77.9% and 87.2% specificity. Their positive (LR+) and negative (LR-) likelihood ratios were respectively 2.760, 2.778, 3.570 and 0.500, 0.495, 0.623, with diagnostic accuracies of 65.3%, 69.0% and 54.3%. In combined VEP + IDAP recordings, an abnormality of at least one test had 83.4% sensitivity, 66.7% specificity, 2.504 LR+, 0.249 LR− and 81.1% accuracy.

Conclusions

In this large database, VEP habituation is significantly reduced and IDAP increased in episodic migraine patients between attacks. Taken alone, neither VEP nor IDAP has sufficient diagnostic accuracy. However, when both tests are performed in the same patient, an abnormality of at least one of them is highly predictive of interictal episodic migraine.

Laboratory tests of headache disorders – dawn of a new era?

Context

The classification of headache disorders has improved over the years, but further work is needed to develop and improve headache diagnosis within headache subtypes. The present review is a call for action to implement laboratory tests in the classification and management of primary and some secondary headaches.

Background

In this narrative review we present and discuss published tests that might be useful in phenotyping and/or diagnosis of long-lasting headache disorders such as migraine, tension-type headache, trigeminal autonomic cephalalgias, trigeminal neuralgia and persisting secondary headaches.

Aim

The palpometer test, quantitative sensory testing, nociceptive blink reflex and autonomic tests may be valuable to phenotype and/or diagnose subforms of migraine, tension-type headache, cluster headache, trigeminal neuralgia and medication-overuse headache. Provocation tests with glyceryl trinitrate (GTN) and calcitonin gene-related peptide (CGRP) may be valuable in subclassification of migraine and cluster headache. Lumbar pressure monitoring and optical coherence tomography may valuable tools to diagnose and follow patients with chronic headache and raised intracranial pressure.

Finding

A number of laboratory tests in headache research are presently available, but have primarily been performed in single research studies or a few studies that differ in methods and patient groups. At present, there is no evidence-based strategy for implementing diagnostic tests, but this could be achieved if well-reputed tertiary headache centers commence developing and implementing laboratory tests in order to improve the classification and treatment of headache patients.

The quality of diagnosis and management of migraine and tension-type headache in three social groups in Russia

Background

Three successive editions of the International Classification of Headache Disorders and multiple guideline papers on headache care have described evidence based diagnosis and treatment of headache disorders. It remains unknown, however, to which extent this has improved the diagnosis and management of headache. That was the aim of our study in which we also analysed differences between three social groups in Russia.

Methods

We studied 1042 students (719 females, 323 males, mean age 20.6, age range 17–40), 1075 workers (146 females, 929 males, mean age 40.4, age range 21–67) and 1007 blood donors (484 females, 523 males, mean age 34.1, age range 18–64). We conducted a semi-structured, validated, face-to-face professional interview. Data on prevalence and associated factors have previously been published. A section of the interview focused on previous diagnosis and treatment, the topic of this paper.

Results

Only 496 of 2110 participants (23%) with headache in Russia had consulted because of headache. Students consulted more frequently (35%), workers and blood donors less often (13% and 14%). Only 12% of the patients with ICHD-3beta diagnosis of migraine and 11.7% with ICHD-3beta diagnosis of tension-type headache (TTH) had previously been correctly diagnosed. Triptans were used by only 6% of migraine patients. Only 0.4% of migraine patients and no TTH patients had received prophylactic treatment.

Conclusion

Despite existing guidelines about diagnosis and treatment, both remain poor in Russia. According to the literature this is only slightly better in Europe and America. Dissemination of existing knowledge should have higher priority in the future.

Neuroimaging overuse is more common in Medicare compared with the VA

OBJECTIVE

To inform initiatives to reduce overuse, we compared neuroimaging appropriateness in a large Medicare cohort with a Department of Veterans Affairs (VA) cohort.

METHODS

Separate retrospective cohorts were established in Medicare and in VA for headache and neuropathy from 2004 to 2011. The Medicare cohorts included all patients enrolled in the Health and Retirement Study (HRS) with linked Medicare claims (HRS-Medicare; n = 1,244 for headache and 998 for neuropathy). The VA cohorts included all patients receiving services in the VA (n = 93,755 for headache and 183,642 for neuropathy). Inclusion criteria were age over 65 years and an outpatient visit for incident neuropathy or a primary headache. Neuroimaging use was measured with Current Procedural Terminology codes and potential overuse was defined using published criteria for use with administrative data. Increasingly specific appropriateness criteria excluded nontarget conditions for which neuroimaging may be appropriate.

RESULTS

For both peripheral neuropathy and headache, potentially inappropriate imaging was more common in HRS-Medicare compared with the VA. Forty-nine percentage of all headache patients received neuroimaging in HRS-Medicare compared with 22.1% in the VA (p < 0.001) and differences persist when analyzing more specific definitions of overuse. A total of 23.7% of all HRS-Medicare incident neuropathy patients received neuroimaging compared with 9.0% in the VA (p < 0.001), and the difference persisted after excluding nontarget conditions.

CONCLUSIONS

Overuse of neuroimaging is likely less common in the VA than in a Medicare population. Better understanding the reasons for the more selective use of neuroimaging in the VA could help inform future initiatives to reduce overuse of diagnostic testing.

Impaired brainstem and thalamic high-frequency oscillatory EEG activity in migraine between attacks

Introduction

We investigated whether interictal thalamic dysfunction in migraine without aura (MO) patients is a primary determinant or the expression of its functional disconnection from proximal or distal areas along the somatosensory pathway.

Methods

Twenty MO patients and twenty healthy volunteers (HVs) underwent an electroencephalographic (EEG) recording during electrical stimulation of the median nerve at the wrist. We used the functional source separation algorithm to extract four functionally constrained nodes (brainstem, thalamus, primary sensory radial, and primary sensory motor tangential parietal sources) along the somatosensory pathway. Two digital filters (1–400 Hz and 450–750 Hz) were applied in order to extract low- (LFO) and high- frequency (HFO) oscillatory activity from the broadband signal.

Results

Compared to HVs, patients presented significantly lower brainstem (BS) and thalamic (Th) HFO activation bilaterally. No difference between the two cortical HFO as well as in LFO peak activations between the two groups was seen. The age of onset of the headache was positively correlated with HFO power in the right brainstem and thalamus.

Conclusions

This study provides evidence for complex dysfunction of brainstem and thalamocortical networks under the control of genetic factors that might act by modulating the severity of migraine phenotype.

Medication overuse headache in Europe and Latin America: general demographic and clinical characteristics, referral pathways and national distribution of painkillers in a descriptive, multinational, multicenter study

BACKGROUND

Medication overuse headache (MOH) is a very disabling and costly disorder due to indirect costs, medication and healthcare utilization. The aim of the study was to describe general demographic and clinical characteristics of MOH, along with the national referral pathways and national painkillers distribution in several European and Latin American (LA) Countries.

METHODS

This descriptive cross-sectional observational study included 669 patients with MOH referred to headache-centers in Europe and LA as a part of the COMOESTAS project. Information about acute medication and healthcare utilization were collected by extensive questionnaires, supplemented with structured patient interviews.

RESULTS

Triptans were overused by 31 % European patients and by 6 % in LA (p < 0.001), whereas ergotamines were overused by 4 % in Europe and 72 % in LA (p < 0.001). Simple analgesics were overused by 54 % in Europe and by 33 % in LA (p < 0.001), while combination-analgesics were more equally overused (24 % in Europe and 29 % in LA). More European patients (57 %) compared with LA patients (27 %) visited general practitioners (p < 0.001), and 83 % of European patients compared to 38 % in LA consulted headache specialists (p < 0.001). A total of 20 % in Europe and 30 % in LA visited emergency rooms (p = 0.007).

CONCLUSION

There are marked variations between LA and Europe in healthcare pathways and in acute medication overuse regarding patients with MOH. This should be considered when planning prevention campaigns against MOH.

European Headache Federation consensus on technical investigation for primary headache disorders

The diagnosis of primary headache disorders is clinical and based on the diagnostic criteria of the International Headache Society (ICHD-3-beta). However several brain conditions may mimic primary headache disorders and laboratory investigation may be needed. This necessity occurs when the treating physician doubts for the primary origin of headache. Features that represent a warning for a possible underlying disorder causing the headache are new onset headache, change in previously stable headache pattern, headache that abruptly reaches the peak level, headache that changes with posture, headache awakening the patient, or precipitated by physical activity or Valsalva manoeuvre, first onset of headache ≥50 years of age, neurological symptoms or signs, trauma, fever, seizures, history of malignancy, history of HIV or active infections, and prior history of stroke or intracranial bleeding. All national headache societies and the European Headache Alliance invited to review and comment the consensus before the final draft. The consensus recommends brain MRI for the case of migraine with aura that persists on one side or in brainstem aura. Persistent aura without infarction and migrainous infarction require brain MRI, MRA and MRV. Brain MRI with detailed study of the pituitary area and cavernous sinus, is recommended for all TACs. For primary cough headache, exercise headache, headache associated with sexual activity, thunderclap headache and hypnic headache apart from brain MRI additional tests may be required. Because there is little and no good evidence the committee constructed a consensus based on the opinion of experts, and should be treated as imperfect.

Headache neuroimaging: Routine testing when guidelines recommend against them

AIMS

The aim of this article is to determine the patient-level factors associated with headache neuroimaging in outpatient practice.

METHODS

Using data from the 2007-2010 National Ambulatory Medical Care Surveys (NAMCS), we estimated headache neuroimaging utilization (cross-sectional). Multivariable logistic regression was used to explore associations between patient-level factors and neuroimaging utilization. A Markov model with Monte Carlo simulation was used to estimate neuroimaging utilization over time at the individual patient level.

RESULTS

Migraine diagnoses (OR = 0.6, 95% CI 0.4-0.9) and chronic headaches (routine, chronic OR = 0.3, 95% CI 0.2-0.6; flare-up, chronic OR = 0.5, 95% CI 0.3-0.96) were associated with lower utilization, but even in these populations neuroimaging was ordered frequently. Red flags for intracranial pathology did not increase use of neuroimaging studies (OR = 1.4, 95% CI 0.95-2.2). Neurologist visits (OR = 1.7, 95% CI 0.99-2.9) and first visits to a practice (OR = 3.2, 95% CI 1.4-7.4) were associated with increased imaging. A patient with new migraine headaches has a 39% (95% CI 24-54%) chance of receiving a neuroimaging study after five years and a patient with a flare-up of chronic headaches has a 51% (32-68%) chance.

CONCLUSIONS

Neuroimaging is routinely ordered in outpatient headache patients including populations where guidelines specifically recommend against their use (migraines, chronic headaches, no red flags).

Is there a persistent dysfunction of neurovascular coupling in migraine?

Changes in cerebral blood flow are one of the main features of migraine attack and have inspired the vascular theory of migraine. This traditional view has been reshaped with recent experimental data, which gave rise to the neural theory of migraine. In this review, we speculate that there might be an important link between the two theories, that is, the dysfunction of neurovascular coupling.

Evidence for brain morphometric changes during the migraine cycle: a magnetic resonance-based morphometry study

Neurophysiological investigations have demonstrated that there are unique fluctuations in the migraine brain functional activity between the ictal and interictal periods. Here we investigated the possibility that there are fluctuations over time also in whole brain morphometry of patients affected by episodic migraine without aura (MO).Twenty-four patients with untreated MO underwent 3T MRI scans during (n = 10) or between attacks (n = 14) and were compared to a group of 15 healthy volunteers (HVs). We then performed voxel-based-morphometry (VBM) analysis of structural T1-weighted MRI scans to determine if changes in brain structure were observed over the course of the migraine cycle.Interictally, MO patients had a significantly lower gray matter (GM) density within the right inferior parietal lobule, right temporal inferior gyrus, right superior temporal gyrus, and left temporal pole than did HVs. Ictally, GM density increased within the left temporal pole, bilateral insula, and right lenticular nuclei, but no areas exhibited decreased GM density.These morphometric GM changes between ictal and interictal phases suggest that abnormal structural plasticity may be an important mechanism of migraine pathology. Given the functional neuroanatomy of these areas, our findings suggest that migraine is a condition associated with global dysfunction of multisensory integration and memory processing.

Evaluation and treatment of migraine in the emergency department: a review

Head pain is the fifth most common reason for emergency department (ED) visits. It is second only to focal weakness as the most common reason for neurological consultation in the ED. This manuscript reviews how patients with migraine, the most common primary headache disorder for which patients seek medical treatment, are managed in the ED. We discuss existing guidelines for head imaging in patients with migraine, recommended pharmacologic treatments, and current treatment trends. We also review studies evaluating the discharge care of migraine patients in the ED. With the goal of standardizing, streamlining, and optimizing ED-based migraine care, we offer ideas for future research to improve the evaluation, treatment, and discharge care of patients who present to an ED with acute migraine.

ACR Appropriateness Criteria Headache

Most patients presenting with uncomplicated, nontraumatic, primary headache do not require imaging. When history, physical, or neurologic examination elicits "red flags" or critical features of the headache, then further investigation with imaging may be warranted to exclude a secondary cause. Imaging procedures may be diagnostically useful for patients with headaches that are: associated with trauma; new, worse, or abrupt onset; thunderclap; radiating to the neck; due to trigeminal autonomic cephalgia; persistent and positional; and temporal in older individuals. Pregnant patients, immunocompromised individuals, cancer patients, and patients with papilledema or systemic illnesses, including hypercoagulable disorders may benefit from imaging. Unlike most headaches, those associated with cough, exertion, or sexual activity usually require neuroimaging with MRI of the brain with and without contrast to exclude potentially underlying pathology before a primary headache syndrome is diagnosed. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Primary headaches and trigeminal neuralgia: neuropathic pain yes or not? Evidences from neurophysiological procedures

Despite the fact that neurophysiological evaluation is not useful for primary headache diagnosis, the nociceptive system exploration through reflexes and evoked potentials procedures may give an aid in understanding the pathophysiological mechanism subtending pain. Neuropathic pain is caused by a lesion or disease of the somatosensory nervous system, which is supported by clinical evaluation and instrumental assessment by trigeminal and nociceptive reflexes and laser evoked potentials. The same methods, applied to migraine and cluster headache, together with evidences coming from structural and functional neuroimaging, excluded the neuropathic origin of pain, which is attaining to symptomatic and idiopathic trigeminal neuralgia, but confirmed a complex dysfunction of pain processing. Tension-type headache fits with a model of non-nociceptive and non-neuropathic pain, subtended by a complex interaction of peripheral muscular and central neuronal factors. The presence of altered modulation of pain concurs with migraine and tension-type headache, and should be taken into account for the choice of the best therapeutic approach.

An investigation of factors that influence general practitioners' referral of computed tomography scans in patients with headache

AIM

In assessing patients with headaches, general practitioners (GPs) play an important role in determining which patients require computed tomography (CT) scans. The purpose of this study was to identify factors that influence GPs' decisions to refer CT scans for patients with headaches.

MATERIALS AND METHODS

A self-administered survey was presented to GPs in Western Australia. One hundred and twenty-eight vignettes describing patients who may have required CT referral for headache were constructed encompassing six clinical variables. Nine vignettes, selected at random, were presented to each respondent. Respondents were asked if they would refer the patient for diagnostic imaging tests, if so, which imaging modalities would they request, how urgently and the perceived benefits of the requested imaging modality. Multinomial logistic regression was used for the multivariate analysis.

RESULTS

We received 105 completed questionnaires (21%). GPs were more likely to refer patients with headaches for diagnostic imaging and CT scans in the following clinical scenarios: patients with a history of colorectal cancer and epilepsy; and patients feeling unwell for the past 6 weeks and headache being exacerbated with valsalva manoeuvrers. Private health insurance and other respondent demographics such as GPs experience and site of care increased imaging referral.

CONCLUSION

GP's referral decisions of diagnostic imaging and CT examinations for patients with headaches are dependent on clinical scenarios and the likelihood of a significant pathology. Further research is required to identify the significant clinical findings with regard to the CT referrals and ensure that CT scans are not requested in patients who are unlikely to benefit.

The real usefulness and indication for migraine diagnosis of neurophysiologic evaluation

According to IHS criteria, a correct clinical history is fully adequate for a diagnosis of migraine. Patients usually perform many useless instrumental and laboratoristic exams and specialistic evaluations. In particular, electroencephalogram (EEG) is often prescribed as a first-line study in migraine patients. The objective is to analyze the indications of EEG in migraine and to evaluate whether its performance may negatively influence the time necessary to obtain a correct diagnosis. In particular, we compared the effects of EEG performance with those related to neuroradiological examinations in terms of time necessary to obtain a migraine diagnosis. 400 consecutive patients affected by migraine without aura were enrolled. Demographic and clinical data were collected. We used an ordinal regression model considering diagnostic delay as the main outcome and EEG and radiological examinations (in particular brain CT) as predictors. Delay was defined as a time to diagnosis greater than 1-year. Age, sex, number of specialists and examinations were included in the model as covariates. EEG represented the most often performed non-radiologic examination in our sample (20 %). It was associated with a significant risk of diagnostic delay [OR 1.66 (95 % CI 1.65-1.66, p < 0.001)]. An appropriate workup, including CT scan and early referral to a headache center was the most time-saving approach, being associated to the lowest probability of diagnostic delay [OR 0.72 (95 % CI 0.63-0.82, p < 0.001)]. EEG is a frequently prescribed exam in migraine. Our data show that it can contribute to diagnostic delay, highlighting only uncertain and unspecific elements. These data confirm the usefulness of a wide application of IHS guidelines, not recommending this exam for migraine detection.

[EEG--when and how?]

BACKGROUND

Electroencephalography (EEG) is used for studying functional disorders of the brain. We provide an overview of the areas where EEG is most strongly indicated and the clinical benefit of the examination.

METHOD

This article is based on articles from personal literature archives and literature searches in PubMed, textbook on methods in clinical neurophysiology, the work of one of the authors on a new European standard for EEG and the authors' clinical experience.

RESULTS

EEG is primarily indicated for assessing suspected epileptic seizures and encephalopathies. Standard EEG, sleep-deprived EEG and long-term EEG examinations are used in diagnosing epilepsy. EEG will identify epileptiform activity in about 90% of patients with epilepsy. Epileptiform EEG activity in these patients will provide support for the diagnosis of epilepsy, while the absence of such activity will not exclude the diagnosis. EEG is also important for classifying the type of epileptic syndrome. In cases of encephalopathy, pathology will take the form of an increase in slow activity on the EEG and will support the diagnosis, but as a rule the EEG finding is non-specific. Findings in some cases may point to the underlying aetiology.

INTERPRETATION

Electroencephalograms must be interpreted by an experienced clinical neurophysiologist or neurologist with specialist expertise in EEG interpretation, and must always be evaluated in the light of the clinical picture.