Cognitive deficits in patients with peripheral vestibular dysfunction.

BACKGROUND AND PURPOSE: Previous studies demonstrated cognitive deficits in patients with peripheral vestibulopathy (PVP) with dysfunction of spatial navigation and orientation, but also documented cognitive decline in nonspatial abilities. This study evaluates cognitive deficits in patients with unilateral vestibulopathy (UVP) as well as bilateral vestibulopathy (BVP) in multiple cognitive domains using common screening tests to reliably detect these deficits in clinical practice. METHODS: This prospective study compared patients with UVP and BVP to age- and sex-matched healthy controls (HC). Tests included the Alzheimer's Disease Assessment Scale (ADAS), Mini-Mental Status Examination (MMSE), Trail Making Test Part A and B, Clock Drawing Task, Executive Interview-25 (EXIT25), Dementia Detection (DemTect), and the Judgment of Line Orientation (JLO). The Montgomery-Åsberg Depression Rating Scale was used to control for depression. Videonystagmography objectively reconfirmed PVP. The Vertigo Symptoms Scale and the Dizziness Handicap Inventory were used to assess for symptom severity and restrictions of activities of daily living. RESULTS: Eighty-one patients (65 UVP, 16 BVP) were compared to 55 HC. Patients showed impairment in ADAS, MMSE, DemTect, EXIT25, and JLO. No differences between UVP and BVP were detected. The relative risk (RR) estimates of developing cognitive deficits following PVP were increased. The RR for the ADAS was higher in BVP (RR = 4.91, 95% confidence interval [CI] = 1.87-12.9, p = 0.001) than in UVP (RR = 3.75, 95% CI = 1.65-8.51, p = 0.002), but was similar for the MMSE and DemTect between groups. CONCLUSIONS: Patients with PVP showed deficits in multiple cognitive domains including nonspatial cognitive abilities. Vestibulopathy could be a risk factor for the development of cognitive impairment.

No structural brain alterations in new daily persistent headache - a cross sectional VBM/SBM study.

OBJECTIVE: To identify grey matter alterations in patients suffering new daily persistent headache to enrich the pathophysiological concept of this rare headache disorder characterised by a distinct, clearly remembered onset and its instant chronification. METHOD: Magnetic resonance-based voxel-based and surface-based morphometry was used to investigate 23 patients suffering from new daily persistent headache and 23 age- and gender-matched healthy controls with 1.5 Tesla MRI.Independent statistical analysis was performed at three sites using statistical parametric mapping, as well as FSL(FMRIB Software Library)-based approaches. RESULTS: No grey matter changes were detected using this sophisticated and cross-checked method. CONCLUSION: The absence of structural brain changes in patients with new daily persistent headache contribute to the recent discussion regarding structural alterations in primary headache disorders in general and does not provide evidence for grey matter changes being associated with the pathophysiology of new daily persistent headache. Future research will have to determine the underlying pathophysiological mechanisms of this disorder.

Secondary headache attributed to exposure to or overuse of a substance.

BACKGROUND: Secondary headaches attributed to exposure to or the overuse of a substance are classified under chapter eight in the International Classification of Headache Disorders 3rd edition. Three distinct sub-chapters consider: 1. Headache attributed to exposure to a substance, 2. Medication overuse headache, and 3. Headache attributed to substance withdrawal. Headache attributed to exposure to a substance refers to a headache with onset immediately or within hours after the exposure, while medication overuse headache is a headache occurring on 15 or more days per month that has developed as a consequence of regular usage of acute headache medication(s) for more than three consecutive months in a patient with a pre-existing primary headache disorder. The withdrawal of caffeine, oestrogen, and opioids is most often associated with the development of headache. DISCUSSION: Despite the current headache classification, there is no certainty of a causal relationship between the use of any substance and the development of headache. Some substances are likely to provoke headache in patients that suffer from a primary headache disorder like migraine, tension-type headache or cluster headache, while others were described to cause headache even in people that generally do not get headaches. Toxic agents, such as carbon monoxide (CO) are difficult to investigate systematically, while other substances such as nitric oxide (NO) were specifically used to induce headache experimentally. If a patient with an underlying primary headache disorder develops a headache, in temporal relation to exposure to a substance, which is significantly worse than the usual headache it is considered secondary. This is even more the case if the headache phenotype is different from the usually experienced headache characteristics. Medication overuse headache is a well-described, distinct disease entity with only marginally understood pathophysiology and associated psychological factors. Managing medication overuse headache patients includes education, detoxification, prophylactic treatments and treating comorbidities, which is reflected in available guidelines. Viewing medication overuse headache as a separate entity helps clinicians and researchers better recognise, treat and study the disorder. CONCLUSION: Identification of substances that may cause or trigger secondary headache is important in order to educate patients and health care professionals about potential effects of these substances and prevent unnecessary suffering, as well as deterioration in quality of life. Treatment in case of medication overuse and other chronic headache should be decisive and effective.

Sensitized rotatory motion perception and increased susceptibility to motion sickness in vestibular migraine: A cross-sectional study.

BACKGROUND AND PURPOSE: Vestibular migraine (VM) patients are ictally and interictally hypersensitive for self-motion and visual perception. Increased cortical excitability of the vestibular system represented by lowered motion perception thresholds might play an important role in the pathophysiology of VM. We aimed to compare motion perception thresholds and the vegetative response to rotatory motion, as well as the vestibulo-ocular reflex (VOR) during rotation in VM patients compared to healthy controls (HC). METHODS: In this cross-sectional study, 28 female VM patients in the interictal state and 33 age- and gender-matched HC were investigated sitting in a motorized rotary chair shielded regarding visual and acoustic stimuli for 20 min with slowly increasing velocity (maximum = 72°/s). The motion perception threshold was indicated by the participants by pushing a button. During and after rotation, participants rated the presence and extent of motion sickness using a sickness rating scale. RESULTS: We detected lower motion perception thresholds (7.54°/s vs. 23.49°/s; p < 0.001) in VM patients compared to HC but no difference at the basic VOR thresholds. Furthermore, the patients showed enhanced susceptibility to motion sickness during and after the rotation. CONCLUSIONS: We provide evidence for decreased motion perception thresholds and pronounced susceptibility to motion sickness in VM patients in the interictal state, which could indicate alterations in higher levels of vestibular processing. Future studies should determine whether this could be the pathophysiological hallmark of VM either as a unique disease entity or in differentiation from other forms of migraine.

Reduced vestibular perception thresholds in persistent postural-perceptual dizziness- a cross-sectional study.

BACKGROUND: Persistent postural-perceptual dizziness (PPPD) is the most common functional vestibular disorder. A multisensory mismatch altered by psychological influences is considered to be an important pathophysiological mechanism. Increased cortical and subcortical excitability may play a role in the pathophysiology of PPPD. We hypothesized that decreased motion perception thresholds reflect one mechanism of the abnormal vestibular responsiveness in this disorder. We investigated the vestibular perception thresholds and the vestibular ocular reflex with a rotatory chair experiment to gain insights in the processing and adaption to vestibular provocation. METHODS: In this cross-sectional study 26 female PPPD patients and 33 healthy female age matched controls (HC) were investigated sitting in a motorized rotary chair shielded regarding visual and acoustic stimuli. The chair was rotated for 20 minutes with slowly increasing velocity to a maximum of 72°/s. We functionally tested motion perception thresholds and vegetative responses to rotation as well as vestibular-ocular reflex thresholds. We additionally investigated several psychological comorbidities (i.e. depression, anxiety, somatosensory amplification) using validated scores. Conventional dizziness scores were obtained to quantify the experienced dizziness and impact on daily life. RESULTS: PPPD patients showed a significant reduced vestibulo-perceptual threshold (PPPD: 10.9°/s vs. HC: 29.5°/s; p<0.001) with increased motion sensitivity and concomitant vegetative response during and after the chair rotation compared to healthy controls. The extent of increased vestibular sensitivity was in correlation with the duration of the disease (p=0.043). No significant difference was measured regarding nystagmus parameters between both groups. CONCLUSION: PPPD patients showed increased vegetative response as well as decreased vestibulo-perceptual thresholds which are related to disease duration. This is of interest as PPPD might be sustained by increased vestibular excitability leading to motion intolerance and induction of dizziness when exposed to movement.

Green Flags and headache: A concept study using the Delphi method.

OBJECTIVE: The aim of this study was to collect and rate Green Flags, that is, symptoms or pieces of information indicating that a patient is more likely to suffer from a primary than from a secondary headache. BACKGROUND: When assessing headaches, a central question to be answered is whether the pain is primary or secondary to another disorder. To maximize the likelihood of a correct diagnosis, relevant signs and symptoms must be sought, identified, and weighed against each other. METHODS: The project was designed as a Delphi study. In the first round, an expert panel proposed green flags that were rated anonymously in two subsequent rounds. Proposals with an average rating of 4.0 and higher on a scale from 0 to 5 reached consensus. RESULTS: Five Green Flags reached consensus: (i) "The current headache has already been present during childhood"; (ii) "The headache occurs in temporal relationship with the menstrual cycle"; (iii) "The patient has headache-free days"; (iv) "Close family members have the same headache phenotype"; and (v) "Headache occurred or stopped more than one week ago." CONCLUSIONS: We propose five Green Flags for primary headache disorders. None being a pathognomonic sign, we recommend searching for both Green Flags and Red Flags. If both are present, a secondary headache should be suspected. Overall, the application of the Green Flag concept in clinical practice is likely to increase diagnostic accuracy and improve diagnostic resource allocation. Prospective studies in clinical populations should be conducted to validate these Green Flags.

[Neurological complications of hepatitis C infections]. / Neurologische Komplikationen der Hepatitis-C-Infektion.

Chronic hepatitis C virus (HCV) infection is a highly prevalent systemic disease, which can cause a variety of neurological complications. The HCV-associated symptoms can be differentiated into central and peripheral nervous systems as well as the musculature. Important pathomechanisms are HCV-associated autoimmunity (e.g. mixed cryoglobulinemia with polyneuropathy) and direct neurotoxic effects of the virus (e.g. HCV-associated cognitive deficits). Distal symmetric polyneuropathies, small fiber neuropathies and cognitive deficits are the most prevalent neurological manifestations. Furthermore, HCV infection is a risk factor for ischemic and hemorrhagic stroke as well as Parkinson's disease. As HCV infection has become a permanently curable disease in >90% of patients, early identification and antiviral treatment of HCV positive patients is of utmost importance.

Delayed headache after COVID-19 vaccination: a red flag for vaccine induced cerebral venous thrombosis.

BACKGROUND: Headache is a frequent symptom following COVID-19 immunization with a typical onset within days post-vaccination. Cases of cerebral venous thrombosis (CVT) have been reported in adenovirus vector-based COVID-19 vaccine recipients. FINDINGS: We reviewed all vaccine related CVT published cases by April 30, 2021. We assessed demographic, clinical variables and the interval between the vaccination and onset of headache. We assessed whether the presence of headache was associated with higher probability of death or intracranial hemorrhage. We identified 77 cases of CVT after COVID-19 vaccination. Patients' age was below 60 years in 74/77 (95.8%) cases and 61/68 (89.7%) were women. Headache was described in 38/77 (49.4%) cases, and in 35/38 (92.1%) was associated with other symptoms. Multiple organ thrombosis was reported in 19/77 (24.7%) cases, intracranial hemorrhage in 33/77 (42.9%) cases and 19/77 (24.7%) patients died. The median time between vaccination and CVT-related headache onset was 8 (interquartile range 7.0-9.7) days. The presence of headache was associated with a higher odd of intracranial hemorrhage (OR 7.4; 95% CI: 2.7-20.8, p < 0.001), but not with death (OR: 0.51, 95% CI: 0.18-1.47, p = 0.213). CONCLUSION: Delayed onset of headache following an adenovirus vector-based COVID-19 vaccine is associated with development of CVT. Patients with new-onset headache, 1 week after vaccination with an adenovirus vector-based vaccine, should receive a thorough clinical evaluation and CVT must be ruled out.

Remission of chronic headache: Rates, potential predictors and the role of medication, follow-up results of the German Headache Consortium (GHC) Study.

Objectives To estimate remission rates of chronic headache (CH), focusing on potential predictors of headache remission and medication. Methods We used data from the longitudinal population-based German Headache Consortium (GHC) Study (n = 9,944, 18-65 years). Validated questionnaires were used at baseline (t0, 2003-2007, response rate: 55.2%), first follow-up after 1.87 ± 0.39 years (t1, 37.2%) and second follow-up after 3.26 ± 0.60 years (t2, 38.8%) to assess headache type and frequency, use of analgesics and anti-migraine drugs, medication overuse, education, BMI, smoking and alcohol consumption. CH was defined as ≥ 15 headache days/month at t0 over three months. Outcomes were: CH remission (<15 headache days/month at both follow-ups), CH persistence (≥ 15 headache days/month at both follow-ups); all others were considered as partially remitted. To estimate predictors of remission, univariate and multiple logistic regression were calculated. Results At baseline, 255 (2.6%) participants were identified with CH. Of these, 158 (62.0%) participants responded at both follow-ups. Remission was observed in 58.2% of participants, partial remission in 17.7% and persistence in 24.1%. Remission was associated with female sex (adjusted odds ratio: 3.10, 95% confidence interval: 1.06-9.08) and no medication overuse (4.16, 1.45-11.94) compared to participants with persistent CH; participants with higher headache frequency at t0 were less likely to remit (0.90, 0.84-0.97). Medication, age, education, BMI, smoking and drinking showed no effects on remission. Similar results were observed for partial remission. Conclusion The majority of CH participants remitted from CH. Female sex, no overuse of pain medication and lower headache frequency were associated with remission.

Polarity-specific modulation of pain processing by transcranial direct current stimulation - a blinded longitudinal fMRI study.

BACKGROUND: To enrich the hitherto insufficient understanding regarding the mechanisms of action of transcranial direct current stimulation (tDCS) in pain disorders, we investigated its modulating effects on cerebral pain processing using functional magnetic resonance imaging (fMRI). METHODS: Thirteen right-handed healthy participants received 20 min of 1.5 mA tDCS applied over the primary motor cortex thrice and under three different stimulation pattern (1.anodal-tDCS, 2.cathodal-tDCS, and 3.sham-tDCS) in a blinded cross-over design. After tDCS neural response to electric trigeminal-nociceptive stimulation was investigated using a block designed fMRI. RESULTS: Pain stimulation showed a distinct activation pattern within well-established brain regions associated with pain processing. Following anodal tDCS increased activation was detected in the thalamus, basal ganglia, amygdala, cingulate, precentral, postcentral, and dorsolateral prefrontal cortex, while cathodal t-DCS showed decreased response in these areas (pFWE < 0.05). Interestingly the observed effect was reversed in both control conditions (visual- and motor-stimulation). Behavioral data remained unchanged irrespective of the tDCS stimulation mode. CONCLUSIONS: This study demonstrates polarity-specific modulation of cerebral pain processing, in reconfirmation of previous electrophysiological data. Anodal tDCS leads to an activation of the central pain-network while cathodal tDCS does not. Results contribute to a network-based understanding of tDCS's impact on cerebral pain-processing.

Headache in Caucasian patients with Moyamoya angiopathy - a systematic cohort study.

Background Headache is common in patients with Moyanoya angiopathy (MMA), but usually underestimated in its management and not well characterized. Methods A validated self-administered headache screening questionnaire and a telephone interview were used in order to investigate headache characteristics, frequency and pain intensity in a large cohort of 55 German patients with MMA. Results Thirty-seven patients (67.3%) had suffered from headache in the past year. Headache intensity was rated 3.2 ± 1.3 on a verbal rating scale from 0 to 10. Seventeen patients (47.9%) reported migraine-like headache, 10 patients (27.0%) reported tension type-like headache and 10 patients (27.0%) had a combination of both. The majority of patients with migraine-like headache ( n = 10, 58.8%) described migrainous aura. Headache frequency and intensity improved significantly after revascularization surgery; however, nine patients developed new-onset headache postoperatively. Conclusion Headache is very common in MMA, often with a migraine-like phenotype. Tension type-like headache was also found in 27% of patients, which is a new finding that has not been reported before.

No Pattern Alteration in Single Nocturnal Melatonin Secretion in Patients With Hypnic Headache: A Case-Control Study.

OBJECTIVE: To investigate headache-related serum melatonin levels and melatonin excretion rhythmicity in patients with hypnic headache (HH). BACKGROUND: Strict sleep dependency of headache attacks is a pathognomonic feature of HH. Changes in melatonin levels, a marker for circadian rhythm, are assumed to play a pivotal role in the pathophysiology of HH. METHODS: Serum melatonin levels were acquired in nine patients with HH and nine age- and gender-matched healthy controls over a 20-hour time period (12 pm, 4 pm, 7 pm, 10 pm, time of headache, and 8 am). RESULTS: No significant changes of melatonin levels could be detected comparing HH patients and healthy controls. Melatonin excretion rhythmicity was not significantly altered in patients with HH (Mean melatonin level in ng/mL ± SD, patients vs controls at 12 pm: 21.5 ± 9.5 vs 13.6 ± 6.3 [P = .077], 4 pm: 18.4 ± 8.4 vs 14.0 ± 4.7 [P = .222], 7 pm: 19.4 ± 5.1 vs 15.1 ± 4.5 [P = .094], 10 pm: 59.5 ± 45.0 vs 29.4 ± 12.7 [P =.136], headache time: 96.9 ± 68.3 vs 49.1 ± 22.8 [P = .94], and 8 am: 31.6 ± 18.3 vs 26.7 ± 15.6 [P = .489]). CONCLUSION: This study is not able to confirm a significant role of melatonin concentration changes in the pathophysiology of HH and vetoes that melatonin deficiency plays a major role in the pathophysiology of the disorder.

Short Latency Gray Matter Changes in Voxel-Based Morphometry following High Frequent Visual Stimulation.

Magnetic resonance imaging studies using voxel-based morphometry (VBM) detected structural changes in the human brain within periods of months or weeks. The underlying molecular mechanisms of VBM findings remain unresolved. We showed that simple visual stimulation by an alternating checkerboard leads to instant, short-lasting alterations of the primary and secondary visual cortex detected by VBM. The rapidness of occurrence (i.e., within 10 minutes) rather excludes most of the proposed physiological mechanism such as neural or glial cell genesis/degeneration or synapse turnover. We therefore favour cerebral fluid shifts to be the underlying correlate of the here observed VBM gray matter changes. Fast onset gray matter changes might be one important explanation for the inconsistency of VBM study results that often raise concern in regard to the validity of presented data. This study shows that changes detectable by VBM may occur within a few minutes after physiological stimulation and must be considered in future VBM experiments to avoid misinterpretation of results.

[Headache News]. / Neues bei Kopfschmerzen.

A review of the latest and most relevant information on different disorders of head and facial pain is presented. News from epidemiologic studies regarding the relationship between migraine and patent foramen ovale, the cardiovascular risk in migraine, and migraine behavior during menopause, and the development of white matter lesions or migraine genetics are presented. Regarding pathophysiology there are very recent insights regarding the role of the hypothalamus during prodromal phase and the interplay of brain-stem and hypothalamus during the attack. In the last year studies and metaanalysis generated new knowledge for the use of triptans in general as in menstrual related migraine and hemiplegic variants. Furthermore, new hope rises for the CGRP (calcitonin-gene related peptide)-antagonists, as the data for ubrogepant do not suggest hepatotoxicity but efficacy. In prophylactic migraine treatment the news are manly on how the new therapeutic approach with monoclonal antibodies against CGRP or its receptor is moving on. Additional newly generated data for already known prophylactic agents as for new approaches are compactly discussed. Although main developments in headache focus on migraine new data on trigemino-autonomic headache trigeminal neuralgia and new daily persistant headache became available.

Simultaneous early-onset immune thrombocytopenia and autoimmune thyroid disease following alemtuzumab treatment in relapsing-remitting multiple sclerosis.

OBJECTIVE: We report two cases of patients with relapsing-remitting multiple sclerosis with early-onset thrombocytopenia and autoimmune thyroid disease after the first treatment course with 60-mg alemtuzumab. METHODS: Case series and review of the literature. RESULTS: Both patients showed severe thrombocytopenia with platelet counts of 2 × 10(9) and 11 × 10(9)/L, respectively, as well as increased thyroid antibodies within only a few months after initiating alemtuzumab treatment (11 and 9 months). Both patients responded considerably well to medical therapy including corticosteroids and intravenous immunoglobulins with slow platelet recovery over several weeks. Interestingly, both patients were previously treated with fingolimod and showed a marked lymphocytopenia that led to discontinuation. CONCLUSION: These cases emphasize the necessity of careful clinical surveillance and proper education of patients treated with alemtuzumab as proposed by the safety-monitoring program. Previous severe lymphocytopenia under therapy with other disease-modifying therapies may be a risk factor for the development of immune thrombocytopenia.

Hypoechogenicity of brainstem raphe nuclei is associated with increased attack frequency in episodic migraine.

INTRODUCTION: Reduced echogenicity of the brainstem raphe nuclei (BRN) was demonstrated in major depression, possibly indicating serotonergic dysfunction. Postulating that migraine may constitute a "chronic low serotonin syndrome," we aimed to evaluate the echogenicity of midbrain structures, including serotonergic BRN in episodic migraine. METHODS: Transcranial sonography was performed in 39 patients with episodic migraine (median age 35, interquartile range (IQR): 27-47 years; 27 women) and 35 controls (median age 31, IQR: 29-47 years; 19 women). Individuals with concomitant depression were excluded. Echogenicity of BRN, substantia nigra (SN) and third ventricle width was evaluated according to an internationally established examination protocol. RESULTS: Hypoechogenicity of BRN was depicted in 23.1% of migraine patients and 20% of controls, showing no significant difference. Migraine patients with hypoechogenic BRN had significantly higher attack frequency (median 3, IQR 2-5 vs. 1.5, IQR 1-2 days/month; p = 0.029) and a trend toward earlier disease manifestation. The rate of hyperechogenic SN and width of the third ventricle were similar between both groups. We did not observe any differences between migraine patients with and without aura. CONCLUSION: Sonographic findings did not differ between migraine patients and controls. Hypoechogenic BRN correlated to a higher migraine attack frequency, probably indicating more severe disease activity.

Vestibular migraine.

BACKGROUND: The combination of vertigo, dizziness and balance disturbance with migraine is called vestibular migraine. Although it is estimated that up to 1% of the population suffers from this disease, it is still widely unknown and often underdiagnosed. Recently, the International Headache Society and the Báràny Society published the first joint document with mutually accepted diagnostic criteria for vestibular migraine. METHOD: This review summarizes current knowledge on vestibular migraine with regard to epidemiology, clinical presentation, pathophysiology, differential diagnosis and therapeutic options. RESULTS: Approximately 30-50% of patients with migraine report vertigo, dizziness or balance disturbances with at least one migraine attack. Vestibular migraine often appears in a temporal delay to the first onset of migraine headache. In some patients the symptom of sudden onset disequilibrium was the main complaint and more worrisome than the accompanying migraine headache. The duration of attacks varies from a few seconds up to few days. The underlying pathophysiology of vestibular migraine is still widely unknown. As an important differential diagnosis, Ménière's disease has to be considered and excluded. CONCLUSION: As randomized controlled treatment trials are still missing in vestibular migraine, the therapeutic recommendations for vestibular migraine are currently based on the guidelines of migraine.

The association between stress and headache: A longitudinal population-based study.

INTRODUCTION: We studied the association between stress intensity and headache frequency for tension-type headache (TTH), migraine and migraine with coexisting TTH (MigTTH). METHOD: We studied a population-based sample of 5159 participants (21-71 years) who were asked quarterly between March 2010 and April 2012 about headache and stress. Log-linear regression in the framework of generalized estimating equations was used to estimate regression coefficients presented as percent changes to describe the association between stress intensity (modified visual analog scale (VAS) from 0 to 100) and headache frequency (days/month) stratified by headache subtypes and age groups and adjusted for sex, age, frequent intake of acute pain drugs, drinking, smoking, BMI and education. RESULTS: TTH was reported in 31% participants (48.1 ± 12.5years, 51.5% women, 2.2 ± 3.9 mean headache days/month, 52.3 ± 26.7 mean stress), migraine in 14% (44.8 ± 11.3years, 73.3%, 4.5 ± 5.2 days/month, 62.4 ± 23.3), MigTTH in 10.6% (43.5 ± 11.5 years, 61.0%, 3.6 ± 4.8 days/month, 58.6 ± 24.1), 23.6% were unclassifiable, and 20.8% had no headache. In participants with TTH an increase of 10 points on VAS was associated with an increase of headaches days/month of 6.0% (adjusted). Higher effects were observed in younger age groups (21-30/31-40/41-50/51-60/61-71 years: 9.8/10.2/7.0/6.5/3.5%). Slightly lower effects were observed for migraine (4.3%, 8.1/5.1/3.4/6.3/0.3%) and MigTTH (4.2%, 5.5/6.8/6.9/5.8/-0.7%). CONCLUSION: Our study provides evidence for an association between stress intensity and headache frequency.