Osmophobia in allodynic migraineurs: cause or consequence of central sensitization?

Effect of pain-related sodium channels SCN9A and SCN10A polymorphisms in migraine chronification

OBJECTIVE

Based on the frequency of attacks, migraine is classified into two subtypes: episodic (EM) and chronic (CM). Migraine progression from EM to CM is supposed to be affected by various factors, which is known as "migraine chronification. However, the pathophysiology of migraine chronification is multifactorial and still not fully understood. Ion channels are hypothesized to play a role in migraine pathophysiology and are essential for generating and suppressing action potentials, which lie under the pain and related symptoms. Two sodium channel genes, SCN9A and SCN10A, have been reported to be associated with various pain sensitivities. Studies have shown that patients with EM and CM are more sensitive to chronic pain and that pain sensitivity may be a risk factor for chronification. Thus, the current study aimed to determine whether pain sensitivity-related SCN9A and SCN10A polymorphisms affect the EM-to-CM transition.

METHODS

For this purpose, genotyping was performed using TaqMan SNP Assay for the (i) SCN9A rs7595255, rs12622743, and rs11898284, (ii) SCN10A rs6795970, rs6801957 SNPs in Turkish EM and CM patients.

RESULTS

The results showed that SCN9A and SCN10A polymorphisms did not play a role in the development of chronicity. However, the results indicated that the SCN10A rs6795970 polymorphism was associated with osmophobia (p = 0.036).

CONCLUSION

SCN10A rs6795970 polymorphism may be necessary to predict the EM-to-CM transition and identify therapeutic targets. However, further studies are required to confirm the osmophobia association of the SCN10A rs6795970 polymorphism and to investigate the role of these SNPs in chronification.

Identification of Polymorphisms in EAAT1 Glutamate Transporter Gene SLC1A3 Associated with Reduced Migraine Risk

Dysfunction in ion channels or processes involved in maintaining ionic homeostasis is thought to lower the threshold for cortical spreading depression (CSD), and plays a role in susceptibility to associated neurological disorders, including pathogenesis of a migraine. Rare pathogenic variants in specific ion channels have been implicated in monogenic migraine subtypes. In this study, we further examined the channelopathic nature of a migraine through the analysis of common genetic variants in three selected ion channel or transporter genes: SLC4A4, SLC1A3, and CHRNA4. Using the Agena MassARRAY platform, 28 single-nucleotide polymorphisms (SNPs) across the three candidate genes were genotyped in a case-control cohort comprised of 182 migraine cases and 179 matched controls. Initial results identified significant associations between migraine and rs3776578 (p = 0.04) and rs16903247 (p = 0.05) genotypes within the SLC1A3 gene, which encodes the EAAT1 glutamate transporter. These SNPs were subsequently genotyped in an independent cohort of 258 migraine cases and 290 controls using a high-resolution melt assay, and association testing supported the replication of initial findings-rs3776578 (p = 0.0041) and rs16903247 (p = 0.0127). The polymorphisms are in linkage disequilibrium and localise within a putative intronic enhancer region of SLC1A3. The minor alleles of both SNPs show a protective effect on migraine risk, which may be conferred via influencing the expression of SLC1A3.

Latent class analysis of migraine associated vestibular-auditory symptoms

OBJECTIVE

This study aimed to identify the potential subgroups of migraines based on the patterns of migraine associated symptoms, vestibular and auditory symptoms using latent class analysis and to explore their characteristics.

METHOD

A total of 555 patients with migraine participated in the study. Symptoms such as nausea, vomiting, photophobia, phonophobia, osmophobia, visual symptoms, vestibular symptoms (dizziness, vertigo), and auditory symptoms (tinnitus, hearing loss, aural fullness) were assessed. Latent class analysis was performed to identify subgroups of migraines. Covariates such as gender, age of migraine onset, frequency of migraine attacks per month, and family history were also considered.

RESULTS

The analysis revealed four latent classes: the Prominent Vestibular; Prominent Nausea; Presenting Symptoms but not prominent or dominant; and Sensory Hypersensitivity groups. Various covariates, such as gender, age of migraine onset, and frequency of migraine attacks, demonstrated significant differences among the four groups. The Sensory Hypersensitivity group showed the presence of multiple sensory symptoms, earlier age of migraine onset, and higher proportion of females. The Prominent Vestibular group had the highest probability of dizziness or vertigo but lacked the presence of auditory symptoms. The Prominent Nausea group exhibited prominent nausea. The Presenting Symptoms but not prominent or dominant group comprised individuals with the highest migraine attacks per month and proportion of chronic migraine.

CONCLUSION

This study identifies four subgroups of migraines based on the patterns of symptoms. The findings suggest potential different but overlapped mechanisms behind the vestibular and auditory symptoms of migraine. Considering the different patterns of migraine-related symptoms may provide deeper insights for patients' prognosis and clinical decision-making.

Associations between the burdens of comorbid sleep problems, central sensitization, and headache-related disability in patients with migraine

Objective

Sleep disturbances are common in migraine patients and affect quality of life. Central sensitization (CS) is likely to play a role in the increased severity and chronicity of migraine. We hypothesized that the number of comorbid sleep problems would affect headache-related disability through the effects of central sensitization (CS).

Methods

We performed a cross-sectional study including 215 consecutive patients with migraine. Insomnia was defined as a Pittsburgh Sleep Quality Index (PSQI) global score greater than 5. Probable REM sleep behavior disorder (pRBD) was defined as an RBD screening score of 5 or greater. Excessive daytime sleepiness (EDS) was defined as an Epworth Sleepiness Scale score of 10 or higher. Suspected sleep apnea (SA) was defined as patients with snoring or sleep apnea witnessed 3 or more nights a week. CS was assessed by the Central Sensitization Inventory (CSI).

Results

Restless legs syndrome, insomnia, EDS, SA and pRBD were observed in 25.6%, 71.6%, 34.4%, 10.2%, and 21.4%, respectively, of the patients. At least one sleep problem was present in 87.0% of the patients. According to the results of the multinomial logistic regression analysis with no sleep problems as a reference, after we corrected for adjustment factors, the Migraine Disability Assessment (MIDAS) score significantly increased when three or more comorbid sleep problems were present. According to our mediation analysis, an increased number of sleep problems had a direct effect on the MIDAS score after we adjusted for other variables, and the CSI score was indirectly involved in this association.

Conclusion

The present study showed an association between migraine-related disability and the burden of multiple sleep problems, which was partially mediated by CS.

Effects of OnabotulinumtoxinA on Allodynia and Interictal Burden of Patients with Chronic Migraine

BACKGROUND

We primarily aimed to ascertain whether treatment with OnabotulinumtoxinA (BoNTA) might influence the extent of the interictal burden and cutaneous allodynia in patients with chronic migraine (CM).

METHODS

Seventy CM patients, who received three consecutive cycles of BoNTA, were studied. The interictal burden was assessed with the Migraine Interictal Burden Scale (MIBS-4), while cutaneous allodynia was examined with the Allodynia Symptom Checklist (ASC-12) together with PI-NRS VAS to obtain hair brushing scores, and then these were compared from baseline (T0) to the last efficacy evaluation follow-up (T1). Efficacy outcomes, mostly mean headache days (MHD) and "Headache Impact Test" scores, were also assessed between T0 and T1.

RESULTS

BONTA improved the interictal burden, with a decrease in MIBS-4 scoring by an average of -7 at T1, compared to baseline (p < 0.001). The percentage of patients with a moderate/severe interictal burden was substantially decreased. Likewise, BoNTA reduced the extent of cutaneous allodynia, with a significant reduction in both the ASC-12 (1 vs. 6; p < 0.001) and PI-NRS VAS (1 vs. 5; p < 0.001) to hair brushing median scores at T1, compared to baseline. Reduced MHD rates were significantly associated with a smaller interictal burden at T1. The efficacy of BoNTA, with a significant reduction in MHD and HIT-6 scores at T1 compared to T0, was re-confirmed.

CONCLUSIONS

BoNTA resulted in a statistically significant reduction in the interictal burden and also improved cutaneous allodynia. The reduction in ictal burden was associated with the down-scaling of the interictal burden. Hence, BoNTA improved the full spectrum of migraine impairment by diminishing the clinical expression of central sensitization.

Olfactory function assessment of migraine patients by using the Sniffin' sticks test: A clinical study

OBJECTIVE

This as a cross-sectional controlled clinical study. We hypothesis that the olfactory functions in migraine patients may differ from the healthy controls. In this study, we evaluated the olfactory functions by using a Sniffin' Sticks test battery, which is a reliable and semi quantitative test to evaluate for olfactory dysfunction.

METHODS

Patients above 18 years of age who had migraine received a definitive diagnosis of migraine from experienced headache specialists based on the criteria of The International Classification of Headache Disorders-3 were included. Odor threshold, discrimination, and identification parameters were assessed using the "Sniffin' Sticks" test.

RESULTS

One-hundred and one migraine patients (age [mean ± SD], 36.9 ± 10.4 years; range, 18-60 years) and sixty healthy volunteers (age 34.5 ± 13.2 years, range 18-65 years) participated in our study. The median odor threshold score [percentiles 25th-75th] was 8.3 [6.5-9.8] for the migraine group during attack free period and 4.5[3.6-6.0] for the control group. It was found that the migraine group had a median odor discrimination score of 10.0 [10.0-13.0] and the control group 12.0 [11.0-13.0]. These differences were statistically significant (p < 0.001 and p = 0.032 respectively). The median odor discrimination and identification scores were statistically significant higher for the participants with higher educational level group than in those of lower educational group (p < 0.0001). The median odor discrimination and identification scores of those without allodynia (12.0 [10.0-14.0] and 13.0 [10.0-13.0] respectively) were higher than that of those with allodynia (11.0 [9.0-12.0] and 11.0 [10.0-13.0] respectively) (p = 0.037 and p = 0.034 respectively).

CONCLUSIONS

We found that the odor thresholds, discrimination and identification scores of the migraine group demonstrate differences from those of the healthy group and in relation to allodynia.

Roxadustat alleviates nitroglycerin-induced migraine in mice by regulating HIF-1α/NF-κB/inflammation pathway

Sensitization of central pain and inflammatory pathways play essential roles in migraine, a primary neurobiological headache disorder. Since hypoxia-inducible factor-1α (HIF-1α) is implicated in neuroprotection and inflammation inhibition, herein we investigated the role of HIF-1α in migraine. A chronic migraine model was established in mice by repeated injection of nitroglycerin (10 mg/kg, i.p.) every other day for 5 total injections. In the prevention and acute experiments, roxadustat, a HIF-1α stabilizer, was orally administered starting before or after nitroglycerin injection, respectively. Pressure application measurement, and tail flick and light-aversive behaviour tests were performed to determine the pressure pain threshold, thermal nociceptive sensitivity and migraine-related light sensitivity. At the end of experiments, mouse serum samples and brain tissues were collected for analyses. We showed that roxadustat administration significantly attenuated nitroglycerin-induced basal hypersensitivity and acute hyperalgesia by improving central sensitization. Roxadustat administration also decreased inflammatory cytokine levels in serum and trigeminal nucleus caudalis (TNC) through NF-κB pathway. Consistent with the in vivo results showing that roxadustat inhibited microglia activation, roxadustat (2, 10, and 20 μM) dose-dependently reduced ROS generation and inflammation in LPS-stimulated BV-2 cells, a mouse microglia cell line, by inhibiting HIF-1α/NF-κB pathway. Taken together, this study demonstrates that roxadustat administration ameliorates migraine-like behaviours and inhibits central pain sensitization in nitroglycerin-injected mice, which is mainly mediated by HIF-1α/NF-κB/inflammation pathway, suggesting the potential of HIF-1α activators as therapeutics for migraine.

Central Sensitization in Migraine: A Narrative Review

Central sensitization (CS) is an increase in the responsiveness of nociceptive neurons in the central nervous system to their normal afferent input. As a result, even minor irritation can induce severe pain, leading to the chronicity and severity of various diseases, such as neurological disorders. CS is associated with migraine, which is a major neurological disorder that inflicts a high disability in daily life. Specifically, CS is thought to be involved in the pathogenesis of cutaneous allodynia as well as chronification of migraine. In this article, we reviewed the association between CS and migraine, including pathophysiological aspects and evidence from clinical studies. We suggest that appropriate screening and management of CS in migraine could further improve the quality of life of migraine patients.

Pathophysiology and Therapy of Associated Features of Migraine

Migraine is a complex and debilitating disorder that is broadly recognised by its characteristic headache. However, given the wide array of clinical presentations in migraineurs, the headache might not represent the main troublesome symptom and it can even go unnoticed. Understanding migraines exclusively as a pain process is simplistic and certainly hinders management. We describe the mechanisms behind some of the most disabling associated symptoms of migraine, including the relationship between the central and peripheral processes that take part in nausea, osmophobia, phonophobia, vertigo and allodynia. The rationale for the efficacy of the current therapeutic arsenal is also depicted in this article. The associated symptoms to migraine, apart from the painful component, are frequent, under-recognised and can be more deleterious than the headache itself. The clinical anamnesis of a headache patient should enquire about the associated symptoms, and treatment should be considered and individualised. Acknowledging the associated symptoms as a fundamental part of migraine has permitted a deeper and more coherent comprehension of the pathophysiology of migraine.

Interictal osmophobia is associated with longer migraine disease duration

Background

Sensitization to sensory stimuli is an essential feature of migraine attacks. The relationship between the clinical course of migraine and increased sensitivity to olfactory stimuli has been little studied so far.

Methods

We analyzed the frequency and quality of osmophobia depending on the phase of migraine in patients with episodic and chronic migraine treated in an tertiary headache center with regard to gender, age, medical history and migraine disability assessment score (MIDAS). Standardized diagnostic questions were used for the assessment of osmophobia.

Results

In our cross-sectional investigation (n = 113), 38.1% of the patients showed an increased preictal hypersensitivity to odors, whereas 61.9% described ictal and 31.9% interictal hypersensitivity to odors, odor-triggered migraine was described in 30.1%. Median migraine disease duration has been statistically significantly longer in patients who suffered from interictal hypersensitivity to odors (28.5 years vs. 20 years; p = 0.012). There was a significant correlation between interictal hypersensitivity and higher age (54.50 vs. 45; p = 0.015). Patients with higher migraine disability in MIDAS experienced more frequently preictal and interictal olfactory sensitization and odor triggered migraine attacks.

Conclusions

In patients with longer migraine disease duration and higher migraine-related impairment, osmophobia was more frequently observed. These results might support the hypothesis of increasing sensitization with increasing burden of migraine.

Cranial autonomic symptoms in migraine are related to central sensitization: a prospective study of 164 migraine patients at a tertiary headache center

Background

Cranial autonomic symptoms (CASs) during migraine attacks are reported to be quite common regardless of ethnicity. In our previous study investigating 373 migraineurs, we found that 42.4% of them had CASs. The patients with CASs more frequently had cutaneous allodynia than did those without CASs, and we speculated that CASs were associated with central sensitization. The present study searched for substantial evidence on the relationship between CASs and central sensitization in migraine patients.

Methods

This was a prospective cross-sectional study. We studied a new independent cohort of 164 migraineurs who presented to the Tominaga Hospital Headache Center from July 2018 until December 2019. The clinical features of CASs according to the criteria in ICHD-3 (beta) were investigated. We also evaluated central sensitization based on the 25 health-related symptoms utilizing the validated central sensitization inventory (CSI), and each symptom was rated from 0 to 4 resulting a total score of 0–100.

Results

The mean age was 41.8 (range: 20 to 77) years old. One hundred and thirty-one patients (78.9%) were women. Eighty-six of the 164 (52.4%) patients had at least 1 cranial autonomic symptom. The CSI score of the patients with ≥3 CASs reflected a moderate severity and was significantly higher than in those without CASs (41.9 vs. 30.7, p = 0.0005). The score of the patients with ≥1 conspicuous CAS also reflected a moderate severity and was significantly higher than in those without CASs (40.7 vs. 33.2, p = 0.013). The patients in the CSI ≥40 group had lacrimation, aural fullness, nasal blockage, and rhinorrhea, which are cranial autonomic parasympathetic symptoms, significantly more frequently than those in the CSI < 40 group.

Conclusions

Migraine patients with CASs showed significantly greater central sensitization than those without such symptoms. In particular, cranial parasympathetic symptoms were more frequent in centrally sensitized patients than in nonsensitized patients, suggesting that cranial parasympathetic activation may contribute to the maintenance of central sensitization.

Trial registration

This study was retrospectively registered with UMIN-CTR on 29 Aug 2020 (UMIN000041603).

Effect of central sensitization on dizziness-related symptoms of persistent postural-perceptual dizziness

Background

Persistent postural-perceptual dizziness (PPPD) is a chronic functional dizziness symptom triggered by psychological stress, but its pathophysiology is unknown. Central sensitization is considered the cause of functional diseases, such as medically unexplained symptoms, and is a psychosocially affected condition. However, the association between dizziness symptoms in PPPD and central sensitization remains unclear. Thus, we conducted a cross-sectional study on the relation between dizziness symptoms and central sensitization in PPPD.

Methods

We recruited 61 outpatients with dizziness who met the PPPD diagnostic criteria. In addition to the evaluation of dizziness symptoms using the Dizziness Handicap Inventory, the participants were evaluated using the Hospital Anxiety and Depression Scale, Pittsburgh Sleep Quality Index, and Central Sensitization Inventory (CSI). A CSI score of 40 or higher was defined as central sensitization syndrome (CSS), and the severity of each condition in CSS and non-CSS participants was compared. We also evaluated the association between dizziness symptoms and central sensitization and coexisting symptoms using linear multiple regression analysis.

Results

We analyzed the data of 50 valid responses (valid response rate of 82.0 percent). Compared with the non-CSS group, the CSS group had a higher degree of disability owing to dizziness and a higher rate of complications of anxiety and depression. The regression analysis results showed that the severity of central sensitization was a related factor that could enhance the dizziness symptoms of PPPD.

Conclusions

Central sensitization may affect the dizziness symptoms of PPPD as an exacerbating factor.

Cutaneous Allodynia in Migraine: A Narrative Review

Objective

In the present work, we conduct a narrative review of the most relevant literature on cutaneous allodynia (CA) in migraine.

Background

CA is regarded as the perception of pain in response to non-noxious skin stimulation. The number of research studies relating to CA and migraine has increased strikingly over the last few decades. Therefore, the clinician treating migraine patients must recognize this common symptom and have up-to-date knowledge of its importance from the pathophysiological, diagnostic, prognostic and therapeutic point of view.

Methods

We performed a comprehensive narrative review to analyze existing literature regarding CA in migraine, with a special focus on epidemiology, pathophysiology, assessment methods, risk for chronification, diagnosis and management. PubMed and the Cochrane databases were used for the literature search.

Results

The prevalence of CA in patients with migraine is approximately 60%. The mechanisms underlying CA in migraine are not completely clarified but include a sensitization phenomenon at different levels of the trigemino-talamo-cortical nociceptive pathway and dysfunction of brainstem and cortical areas that modulate thalamocortical inputs. The gold standard for the assessment of CA is quantitative sensory testing (QST), but the validated Allodynia 12-item questionnaire is preferred in clinical setting. The presence of CA is associated with an increased risk of migraine chronification and has therapeutic implications.

Conclusions

CA is a marker of central sensitization in patients with migraine that has been associated with an increased risk of chronification and may influence therapeutic decisions.

Development of quality of life assessment questionnaire associated with osmophobia in people with migraine

BACKGROUND

It is important to implement disease-specific precautions to develop quality of life in migraine. The effect of osmophobia, which is one of the specific symptoms of migraine that might help to differentiate migraine from other headache disorders, on quality of life is unknown. The aim of the present study was to develop a practicable and reliable scale that assesses the effect of osmophobia on quality of life in migraine.

METHODS

This cross-sectional study was carried out with 163 patients with migraine and 110 healthy individuals for control group. The scale items were constructed based on after literature review, expert opinions, and preliminary trial stage. A semi-structured interview was conducted with the patients by the Neurologist to evaluate the presence of osmophobia retrospectively. Migraine osmophobia-related quality of life assessment (MORA) consisted of 6 items including personal care, eating or cooking, house cleaning, close relationship, social life and traveling.

RESULTS

The Cronbach's α coefficient was 0.86; and the Guttman split-half coefficient was 0.83. Receiver operating characteristic analysis showed an area under the curve of 0.943 (95%) confidence interval [CI] = 0.902-0.984), a cut off score of > 9.5, a sensitivity of 91.6%, a specificity of 85.7%. Mean scores of the MORA differed between people with migraine (with and without osmophobia) and healthy controls (<0.001).

CONCLUSION

MORA is a valid and reliable self-report questionnaire that assesses the effect of osmophobia on quality of life in migraine. This questionnaire appears to be practicable diagnostic instrument in clinical practice and research.

Osmophobia in primary headache patients: associated symptoms and response to preventive treatments

BACKGROUND

Osmophobia, is common among primary headaches, with prevalence of migraine. The study aimed to evaluate prevalence and clinical characteristics of patients with osmophobia in a cohort of primary headache patients selected at a tertiary headache center. The second aim was to verify the possible predicting role of osmophobia in preventive treatment response in a sub cohort of migraine patients.

METHODS

This was an observational retrospective cohort study based on data collected in a tertiary headache center. We selected patients aged 18-65 years, diagnosed as migraine without aura (MO), migraine with aura (MA) or Chronic Migraine (CM), Tension-Type Headache (TTH); and Cluster Headache (CH). We also selected a sub-cohort of migraine patients who were prescribed preventive treatment, according to Italian Guidelines, visited after 3 months follow up. Patients were considered osmophobic, if reported this symptom in at least the 20% of headache episodes. Other considered variables were: headache frequeny, the migraine disability assessment (MIDAS), Allodynia Symptom Checklist, Self-rating Depression scale, Self-rating Anxiety scale, Pain intensity evaluated by Numerical Rating Scale-NRS- form 0 to 10.

RESULTS

The 37,9% of patients reported osmophobia (444 patients with osmophobia, 726 without osmophobia). Osmophobia prevailed in patients with the different migraine subtypes, and was absent in patients with episodic tension type headache and cluster headache (chi square 68.7 DF 7 p < 0.0001). Headache patients with osmophobia, presented with longer hedache duration (F 4.91 p 0.027; more severe anxiety (F 7.56 0.007), depression (F 5.3 p 0.019), allodynia (F 6 p 0.014), headache intensity (F 8.67 p 0.003). Tension type headache patients with osmophobia (n° 21), presented with more frequent headache and anxiety. A total of 711 migraine patients was visited after 3 months treatment. The change of main migraine features was similar between patients with and without osmophobia.

CONCLUSIONS

While the present study confirmed prevalence of osmophobia in migraine patients, it also indicated its presence among chronic tension type headache cases, marking those with chronic headache and anxiety. Osmophobia was associated to symptoms of central sensitization, as allodynia. It was not relevant to predict migraine evolution after first line preventive approach.

A prospective study on osmophobia in migraine versus tension-type headache in a large series of attacks

Background

In literature, osmophobia is reported as a specific migrainous symptom with a prevalence of up to 95%. Despite the International Classification of Headache Disorders 2nd edition proposal of including osmophobia among accompanying symptoms, it was no longer mentioned in the ICHD 3rd edition.

Methods

We conducted a prospective study on 193 patients suffering from migraine without aura, migraine with aura, episodic tension-type headache or a combination of these. After a retrospective interview, each patient was asked to describe in detail osmophobia, when present, in the following four headache attacks.

Results

In all, 45.7% of migraine without aura attacks were associated with osmophobia, 67.2% of migraineurs reported osmophobia in at least a quarter of the attacks. No episodic tension-type headache attack was associated with osmophobia. It was associated with photophobia or phonophobia in 4.3% of migraine without aura attacks, and it was the only accompanying symptom in 4.7% of migraine without aura attacks. The inclusion of osmophobia in the ICHD-3 diagnostic criteria would enable a 9.0% increased diagnostic sensitivity.

Conclusion

Osmophobia is a specific clinical marker of migraine, easy to ascertain and able to disentangle the sometimes challenging differential diagnosis between migraine without aura and episodic tension-type headache. We recommend its inclusion among the diagnostic criteria for migraine as it increases sensitivity, showing absolute specificity.

Constipation is associated with tension type headache in women

ABSTRACT Tension-type headaches (TTH) and irritable bowel syndrome (IBS) are comorbid diseases affecting, especially, women. One of the underlying mechanisms for both is autonomic dysfunction in the brain-gut axis. We aimed to evaluate the factors accompanying TTH and their relation to functional gastrointestinal disorders. Methods: Women diagnosed with TTH were questioned about headache pattern and severity, and accompanying factors, as well as being screened for IBS according to the Rome III criteria. The participants were divided into two groups: constipation-dominant IBS (IBS-C) group and “others”, with a total of 115 individuals included in the study. Results: Of the 115 patients; 48 (41.8%) of the women had IBS-C criteria while 67 (58.2%) described mixed-type IBS or diarrhea-dominant IBS. There were no significant differences in terms of mean age (p = 0.290), body mass index (p = 0.212), visual analog scale (p = 0.965), duration of attacks (p = 0.692), and episodic/chronic type (p = 0.553). Osmophobia was seen in 43.5%; phonophobia in 68.7%, and photophobia in 47.0% of the patients, and only osmophobia was significantly associated in women in the IBS-C group (p = 0.001). Conclusion: In female patients with TTH, a higher level of constipation was detected. The relationship of these two diseases suggests that they may share common mechanisms. This is the first study showing the relationship of osmophobia with constipation.

A lost track in ICHD 3 beta: A comprehensive review on osmophobia

Background

Osmophobia (Os) has been reported to be much more prevalent in migraine (M) than in other primary headaches, and its high specificity in the differential diagnosis between M and tension-type headache (TTH) has been reported. Os was included in the ICHD II Appendix as a diagnostic criterion of M. It disappeared in ICHD-3 beta. To understand this choice, we reviewed the literature after 2004.

Methods

This was a systematic review. We searched in PubMed, MEDLINE and Cochrane library for “osmophobia”, “odour/odorphobia AND headache”, “odour/odor hypersensitivity AND headache” and “olfactory hypersensitivity AND headache”.

Results

112 papers cited Os as an accompanying symptom of headache; 16 focused on Os in M diagnosis. With the data from 40 articles, we calculated the pooled prevalence of Os in 14,360 patients (2281 pediatric) affected by M (n = 12,496) and TTH (n = 1864). In M, the prevalence was 48.5% (CI 95% 41.4 to 55.8%) in adults and 23.4% (CI 95% 15.7 to 33.4%) in pediatric patients; in TTH, the prevalence was 8.9% (CI 95% 4.6 to 13.5%) in adults and 7.9% (CI 95% 3.3 to 18.1%) in pediatric patients. Ten of these papers allowed us to calculate the sensibility and specificity of Os in differential diagnosis between M and TTH. In adults, the value of specificity was 94.1% (CI 95% 88.9 to 96.9%), and sensitivity was 51.4% (CI 95% 38.4 to 64.2%). In pediatric patients, specificity was 92.0% (CI 95% 81.9 to 96.7%), and sensitivity was 22.1% (CI 95% 10.1 to 41.8%).

Conclusion

The literature endorses the inclusion of Os among M diagnostic criteria. On this ground, the decision to remove Os from ICHD 3 beta appears unjustified and a revision of this choice is recommended.

Somatosensory temporal discrimination remains intact in tension-type headache whereas it is disrupted in migraine attacks

Background and objective

Somatosensory temporal discrimination was recently reported as prolonged during migraine attacks, which is consistent with disrupted sensorial perception in migraine. However, knowledge about central sensory processing in tension-type headache is still lacking. This prospective, controlled study aimed to investigate somatosensory temporal discrimination thresholds in tension-type headache.

Methods

The study included 10 tension-type headache patients, 10 migraine patients and 10 healthy volunteers without headache. Somatosensory temporal discrimination thresholds were evaluated during the headache attacks of tension-type headache and migraine patients.

Results

Somatosensory temporal discrimination thresholds of tension-type headache patients (39.0 ± 5.5 ms for the right hand and 40.6 ± 4.6 ms for the left hand) were significantly lower than those of episodic migraine patients (137.1 ± 35.8 ms for the right hand and 118.4 ± 34.3 ms for the left hand, p < 0.0001 and p < 0.0001 respectively), and comparable to those of healthy volunteers (38.6 ± 5.3 ms for the right hand and 38.3 ± 7.2 ms for the left hand, p = 0.79 and p = 0.45 respectively).

Conclusion

Central sensory processing, as tested by somatosensory temporal discrimination, was remarkably disrupted during the headache attacks in migraineurs, whereas it remained intact in the tension-type headache patients.

Psychosocial difficulties in patients with episodic migraine: a cross-sectional study

To explore the relationships between psychosocial difficulties (PSDs), quality of life (QoL), and disability and to explore the degree to which PSDs can be predicted by demographic variables, clinical variables, and risk and protective factors. Patients with episodic migraine completed a protocol inclusive of PARADISE 24 questionnaire (the 24-item Psychosocial Difficulties Relevant to Brain Disorders questionnaire), a new questionnaire that captures PSDs relevant to brain disorders, and assessments of disability, QoL, disease severity, presence of comorbidities, social support, and clinical and risk factors (i.e., smoking and body mass index). Spearman's correlation was used to address the relationship between PARADISE 24, and the assessments of disability and QoL; multivariable linear regression analysis was carried out to address PARADISE 24 predictors. Eighty patients were enrolled (86.3 % females, mean age 44.5). PARADISE 24 was well correlated with disability (ρ = 0.787) and moderately with QoL (ρ = -0.526). The regression analysis shows that younger age, higher migraine frequency, higher comorbidities index and being a smoker were predictors of PARADISE 24 (R ²: 0.470). Addressing the burden associated with PSDs in migraineurs is important as these might be the reason why patients look for specialists in headache disorders. PARADISE 24 represents a viable way to address patients' difficulties in daily practice.

Brain plasticity and migraine transformation: fMRI evidences

INTRODUCTION

Chronification transforms episodic migraine into the pathologic chronic form. Biological characteristics of the migrainous brain progressively change, in predisposed subjects, under the repetition of external and internal stimuli. Modifications involve neurons, synapses, neurotransmitters, receptors, connectivity and pain control. f-MRI is a promising way to explore the still unclear biology of this progression. Areas covered: Data included were obtained from the most relevant and updated works available on PubMed about this topic. We summarized the pathophysiology of migraine chronification and of brain plasticity, and we described the different fMRI techniques and their main evidences about migraine transformation. Expert commentary: Functional-MRI has revealed many aspects regarding the peculiarity of the migrainous brain and its tendency toward chronicity but a series of questions are still open: What are the hallmarks of the predisposition to chronification? Which elements are the cause and which the consequence of this process?

Phenotypic features of chronic migraine

BACKGROUND

Chronic migraine is a disabling, under-recognized, and undertreated disorder that increases health burdens. The aim of this study was to evaluate phenotypic features and the relevance of accompanying symptoms of migraine attacks in chronic migraine.

METHOD

This study was conducted as part of an ongoing Turkish Headache Database Study investigating the clinical characteristics and outcomes of headache syndromes in the Turkish population. The electronic database was examined retrospectively, and 835 patients with chronic migraine were included.

RESULTS

Patient group consisted of 710 women and 125 men (85 and 15 %, respectively). Mean patient age was 36.8 ± 13.5 years, median value of migraine onset was 60 months (18-120), median headache frequency was 25 days per month (16-30), median of attack duration was 12 h (4-24), and median of intensity was eight (7-9). Increasing headache days per month were inversely related with the presence of nausea, vomiting, phonophobia, and photophobia. Longer duration of headache (months) and higher visual analog scale (VAS) for headache intensity were associated with all accompanying symptoms. Phonophobia, nausea, photophobia, and vomiting were the most frequent accompanying symptoms (experienced by 80.2, 77.6, 71.2, and 40.9 % of patients, respectively). Osmophobia was also frequent in chronic migraine patients (53.4 %) and was closely associated with other accompanying symptoms. Vertigo and dizziness were observed less frequently, and they were not associated with accompanying symptoms.

CONCLUSION

Phenotype of chronic migraine may be associated with the course of chronification. Duration of illness and attack intensity were closely related with the presence of accompanying symptoms, although headache frequency was found to be inversely related to the presence of accompanying symptoms. Osmophobia was also a frequent symptom and was closely related with other accompanied symptoms, unlike vertigo and dizziness. Inclusion of osmophobia into the diagnostic criteria might improve accurate diagnosis of chronic migraine.