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

Migraine is a primary headache characterized by recurrent attacks of head pain associated with nausea or vomit, photophobia, phonophobia and osmophobia. The presence of osmophobia during migraine attacks seems to be a very specific complaint. Cutaneous allodynia (CA) is very common in migraineurs, and it is the most evident clinical manifestation of central sensitization, a mechanism involved in migraine chronification. This study was aimed at identifying the possible correlation between osmophobia and CA in migraineurs. 673 migraineurs were studied (492 episodic, 181 chronic). The prevalence of both CA and osmophobia was higher in chronic than in episodic migraineurs. The association between these two symptoms was significant in chronic migraineurs at Chi square test. The highlighted relationship between CA and osmophobia may be interpreted in different ways: central sensitization induced by recurrent pain stimulation may in parallel induce a distortion of both cutaneous sensitivity (CA) and olfaction (osmophobia); alternatively, the recurrent olfactory stimulation in subjects with a hypersensitivity to olfactory stimuli may co-work with repetitive pain stimulation to induce the central sensitization process.

Negative emotions in migraineurs dreams: the increased prevalence of oneiric fear and anguish, unrelated to mood disorders.

BACKGROUND: Migraineurs brain has shown some functional peculiarities that reflect not only in phonophobia, and photophobia, but also in mood and sleep. Dreaming is a universal mental state characterized by hallucinatory features in which imagery, emotion, motor skills, and memory are created de novo. We evaluated dream contents and associated emotions in migraineurs. MATERIALS AND METHODS: 412 subjects: 219 controls; and 148 migraineurs (66 with aura, MA; 82 without aura, MO), and 45 tension type headache patients (TTH). A semistructured retrospective self-reported questionnaire was used to evaluate dreams. The Generalized Anxiety Disorder Questionnaire (GAD-7), and the Patient Health Questionnaire (PHQ-9) were administered to evaluate anxiety and depression. RESULTS: Migraineurs showed increased levels of anxiety (P = 0.0002 for MA versus controls, P = 0.004 for MO versus controls). Fear and anguish during dreaming were more frequently reported by migraine patients compared to controls, independently by anxiety and depression scores. DISCUSSION: The brain of migraineurs seems to dream with some peculiar features, all with a negative connotation, as fear and anguish. It may be due to the recorded negative sensations induced by recurrent migraine pain, but it may just reflect a peculiar attitude of the mesolimbic structures of migraineurs brain, activated in both dreaming and migraine attacks.

Is the brain of migraineurs "different" even in dreams?

Migraineurs brain is hyper-excitable and hypo-metabolic. Dreaming is a mental state characterized by hallucinatory features in which imagery, emotion, motor skills and memory are created de novo. To evaluate dreams in different kinds of headache. We included 219 controls; 148 migraineurs (66 with aura-MA, 82 without aura-MO); 45 tension type headache (TTH) patients. ICHD-II diagnostic criteria were used. Ad hoc questionnaire was used to evaluate oneiric activity. The Generalized Anxiety Disorder Questionnaire, and the Patient Health Questionnaire were administered to evaluate anxiety and mood. The prevalence of dreamers was similar in different groups. Frequency of visual and auditory dreams was not different between groups. Migraineurs, particularly MA, had an increased frequency of taste dreams (present in 19.6 % of controls, 40.9 % of MA, 23.2 % of MO, 11.1 % of TTH, p < 0.01), and of olfactory dreams (present in 20 % of controls, 36 % of MA, 35 % of MO and 20 % of TTH, p < 0.01). Anxiety and mood did not influence these results. The increased frequency of taste and olfactory dreams among migraineurs seems to be specific, possibly reflecting a particular sensitivity of gustative and olfactory brain structures, as suggested by osmofobia and nausea, typical of migraine. This may suggest the role of some cerebral structures, such as amygdala and hypothalamus, which are known to be involved in migraine mechanisms as well in the biology of sleep and dreaming.

Blood pressure during nocturnal sleep in headache.

AIM: Interactions between blood pressure control, sleep and headache have been largely studied, although not well understood. We designed a study trying to simultaneously evaluate all three aspects in the same subjects. We particularly concentrated on the observation of physiological blood pressure circadian rhythm, and the presence of cutaneous allodynia correlated to headache. Objective of the study was to investigate blood pressure during nocturnal sleep in patients that underwent a blood pressure 24 hours monitoring, and at the same time the presence of headache and of sleep behavioural alterations. METHODS: Blood pressure 24 hours monitoring was performed by an ambulatory blood pressure (ABP) monitor (Space Labs) with its ad hoc software. Headache diagnosis was made according to ICHD-II criteria. Presence of allodynia and sleep behavior were evaluated through semi-structured ad hoc questionnaires. RESULTS: A total of 195 subjects were included, of which 122 without headache (mean age 60.4±11.6 years, 78 men and 44 women) and 73 with history of headache, (mean age 54.2±12.5 years, 18 men and 55 women). Fifty-one headache patients had migraine (mean age 52.6±11.7 years, 11 men and 40 women) and 22 tension type headache (TTH - mean age 58.0±13.5 years, 7 men and 15 women). Allodynia was found in 30 out of 73 headache patients: 23 out of 51 in the migraine group and in 7 out of 22 in the tension-type one. The physiological reduction of blood pressure during night (dipping) was more conserved among headache patients (34 dippers out of 73 subjects, 46,6%) with respect to subjects without headache (40 dippers out of 122, 32,8%) and that this border-line difference was more strongly significant comparing allodynic subjects (19 dippers out of 30, 63.3%) with both non-headache (40 dippers out of 122, 32.8%, P<0.001) and non-allodynic (15 out of 43, 34.9%, P<0.05) ones. No significant difference was observed between headache patients and subjects without headache in terms of mean systolic and diastolic pressure, neither between migraine and TTH. CONCLUSION: Allodynic headache patients seem to maintain a more physiologic pressure circadian rhythm. While considering the possibility of selection bias, the hypothesis of an allostatic function of headache and allodynia in patients with unbalanced blood pressure could be made.

Central sensitization in photophobic and non-photophobic migraineurs: possible role of retino nuclear way in the central sensitization process.

The aim of the present study was to investigate the possible relationships between the presence of headache-related photophobia and migraine-associated allodynia--a hallmark of central sensitization--among patients with different migraine types. A sample of 456 migraineurs was studied. Our results showed that photophobia was present in a high proportion of patients, with similar figures in patients with episodic migraine or CM, and confirmed that the prevalence of allodynia was higher among CM patients than in those with episodic migraine. We found a clear association between migraine-related allodynia and photophobia only in CM patients. Overall, these findings suggest that light stimulation may contribute to central sensitization of pain pathways in migraineurs, possibly contributing to progression into chronic forms. The possible connections underlying this type of sensitization is offered by the recently published data on a non-image-forming visual retino-thalamo-cortical pathway which may allow photic signals to converge on a thalamic region which is selectively activated during migraine headache.