Patients and procedure
A total of 136 consecutive children/adolescents suffering from migraine without aura (MoA, ICHD-III) were included (67 males and 69 females; age range 8–17 years; mean age 11.5 ± 2.3 years). They were consecutively chosen from patients referred for consultation to our Headache Centre. Patients suffering from any other neurological or internal disease were excluded from our study.
At the time of the psychological evaluation, none of the patients were receiving drugs for migraine prophylaxis and none of them had been treated with other drugs acting on the central nervous system. Some children/adolescents had previously taken symptomatic drugs for pain relief.
At the initial visit, all patients were given a headache diary where they had to sign the main features of their headache for the next two months. Data on the clinical characteristics of migraine, including frequency and intensity of the attacks, were issued from the diary that was brought back at the second consultation (two months after the initial visit). Patients were divided in 2 groups according to headache attack frequency: 1) high frequency (HF) patients, having from weekly to daily episodes, and 2) low frequency (LF) patients, showing ≤ 3 episodes per month.
The cut point was chosen for three reasons: (1) patients with chronic and intermediate frequencies were too few to undergo reliable statistic comparison; 2) a mere distinction between chronic and episodic patients would have led to include individuals with high, but not chronic, headache episode frequency in the same group of patients with very low attack frequency; 3) the chosen cut point had the rationale to distinguish patients who need prophylactic treatment from those who do not.
According to headache attack intensity, patients were classified in 3 groups: (1) mild pain (MP), allowing the patient to continue his/her daily activities; (2) moderate pain (MoP) leading to interruption of patient activities; and (3) severe pain (SP), forcing the child to go to bed.
The MERS investigation was carried out by an interview during the initial assessment of the child. The interview was designed to provide sufficient information concerning the characteristics of the symptoms in order to allow them to be classified as MERS or otherwise. Possible organic causes of the symptoms, e.g., other neurological diseases for benign paroxysmal vertigo or gastroenterological abnormalities for abdominal migraine and cyclical vomiting, were investigated and their occurrence led to patient exclusion. Diagnosis was based on the presence of the typical clinical features of the MERS included in the ICHD-III (cyclical vomiting, abdominal migraine, benign paroxysmal torticollis and benign paroxysmal vertigo). Although not classified among the “episodic syndromes” in the International Classification, we also included limb pain and motion sickness, very common among headache children [
4,
6]. The diagnosis of limb pain was based on the following criteria: 1) pain is usually non-articular, located in the lower extremities, and is usually bilateral; 2) pain appears late in the day or is nocturnal, often awaking the child; 3) parents often report pain on days of increased physical activity; 4) duration ranges from minutes to hours, and the intensity can be mild or very severe; 5) there are no objective signs of inflammation on physical examination; 6) limb pain are episodic, with pain free intervals from days to months [
18]. The diagnosis of motion sickness was made in children experiencing discomfort when perceived motion disturbs the organs of balance; they could show nausea, vomiting, pallor, cold sweats, hypersalivation, hyperventilation and headaches [
19]. Both patients who had complained MERS only in the past and those who continued to suffer from one or more MERS were included.
Psychological evaluation was performed in a single session by the same examiner (S.T.) with a specific training on the psychological assessment of children and adolescents. In order to exclude a possible direct effect of pain on psychological assessment, we ensured us that no patient had a headache attack within 24 h before the psychological study. All the patients were able to understand and to complete the tasks. None of them had ever had a previous psychological screening. The study was approved by the ethical committee of Bambino Gesù Children’s Hospital and all participants and their parents gave signed, informed consent to participate to the study.
Psychological tool employed in our study was the Italian SAFA battery of tests (Psychiatric scales for self-administration for youths and adolescents) [
20,
21]. It allows examiners to explore a wide series of symptoms and psychological conditions. The entire battery includes a total of six scales (each with subscales) that can also be used separately. It evaluates anxiety-related areas (SAFA-A), depression-related areas (SAFA-D), obsessive–compulsive symptoms (SAFA-O), somatic concerns (SAFA-S), psychogenic eating disorders (SAFA-P) and phobias (SAFA-F). The administration lasts between 30 and 60 min. The SAFA battery is organized to fit the mode of understanding and evaluation of a large age group: each questionnaire is composed of a version for children aged from 8 to 10 years (identified with the letter “e”) and a version for subjects ranging from 11 to 18 years (identified with the letters “ms”). Only the scale for anxiety presents three distinct versions: 8–10 years (“e”), 11–13 years (“m”) and 14–18 years (“s”). There are three possible responses to each item: ‘true, false and partly true’; the sum of points achieved in each scale and subscale can be converted into
T scores, sten points and percentiles. On the basis of the obtained scores, it is possible to build a general profile and/or individual profiles within the single scales. The scales showed good internal consistency (Cronbach alpha > 0.80) and test-retest stability. The psychometric properties have been established for each scale [
20].
According to the aim of our study, we administered the scale for assessment of anxiety (SAFA-A) and somatization (SAFA-S). SAFA-A includes several subscales (“Generalized anxiety”, “Social anxiety”, “Separation anxiety”, “School anxiety”) and produces a “Total anxiety” score. SAFA-S considers somatic symptoms and hypochondria.
Statistical analysis
Statistical evaluation was performed using Statistical Package for the Social Sciences (SPSS 18.0) software. According to the aims of our study, patients were divided in two groups (patients with and without MERS). Moreover, only the patients with MERS were grouped on the base of attack frequency (LF and HF groups) and headache pain severity (MP, MoP, and SP groups). Initially, we analyzed the frequencies of each category of variables (frequency, intensity). We used descriptive statistics expressed as means, SD and percentages to describe the basic features of our sample.
Analysis of variance (ANOVA) and t-test were used to estimate differences between group means. Data were analyzed in two stages: 1) migraine children with and without MERS were compared, and 2) in migraineurs with MERS, a series of one-way ANOVAs were carried out to further explore differences of anxiety and somatization, as function of the different levels of headache attack frequency and intensity. To assess whether there was a relationship between anxiety and somatization in our patients with MERS, we performed a series of correlation analyses between all SAFA-A and SAFA-S subscales. Pearson correlation coefficients with Bonferroni’s corrections for multiple comparisons were calculated.
The level of statistical significance was set at P < 0.05.