Primary headaches, attention deficit disorder and learning disabilities in children and adolescents

Children and adolescents aged 6–18 years, who were referred by their primary physician for neurological assessment due to headaches to the outpatient pediatric neurology clinics at Bnai-Zion Medical Center and at Meyer Children’s Hospital, Haifa, during the years 2009–2010.

Children and adolescents aged 6–18 years, that met the diagnostic criteria for either migraine or tension type headache (TTH) according to the International Headache Society [19], whose parents signed an informed consent form.

Children younger than 6 years, children with developmental delay, mental retardation, seizure disorder, major psychiatric disorders, hydrocephalus or any other systemic condition that may have an impact on headaches and brain function.

After the Rambam Medical Center IRB's approval (#0115-11) was obtained, a retrospective review of medical records was carried out. During their initial and follow up visits to the pediatric neurology clinic all patients and parents were interviewed using a semi-structured interview and were asked to answer a written questionnaire. Both the interview and the questionnaire included questions regarding demographics, patient’s and family medical history, headaches history (age at onset, location, quality, frequency, duration of episodes, aura, associating symptoms). Parents and patients have evaluated their school performance as poor (40–50/100), average (60–70/100), good (80–90/100) and excellent (90/100). Patients were subdivided into groups according to headache episodes’ duration and frequency. The division for duration was: A-less than 2 hours, B-2 to 4 hours, C-more than 4 hours, and for frequency: A-less than 4 episodes per month, B-five to ten episodes per month, C-more than 10 episodes per month.

Children were diagnosed as ADHD if they fulfilled the DSM-4 criteria [20] using the Conners’ Parents and Teacher Rating Scales-Revised [21]. This test is typically used to measure symptoms of ADHD (hyperactivity, inattention, and impulsivity). The diagnosis of learning disabilities was based on DSM-4 criteria [20] and formal psycho-educational assessment.

The association between headache duration and frequency, ADHD, learning disabilities and academic achievements was assessed.

Data was summarized as proportions or means and standard deviations. Data was analyzed using standard statistical methods. Bivariate analyses of the associations between headache diagnosis, frequency and duration of headache and background factors (gender, learning disabilities, ADHD and school functioning) were conducted with Mann–Whitney U tests. Multivariate analyses of the associations between headache diagnosis and learning disabilities, ADHD and school functioning, were conducted with nominal regressions. Multivariate analyses of the associations between frequency and duration of headache and learning disabilities, ADHD and school functioning, were conducted with logistic regressions. Analyses for the total sample, in both nominal and logistic regressions, were adjusted for age and gender. No adjustment for multiplicity was made to the alpha levels of the statistical tests.

Frequency of headache episodes was found to be associated with lower academic achievements. Poor to average school performance was more prevalent among children with more than 10 episodes of headache per month compared to children with fewer headache episodes (48.5% vs. 33.7%, p = 0.032). The same was found for low academic achievements, they were more prevalent among those with more than 10 headache attacks per month when compared to patients with less frequent episodes (OR 2.00, CI-1.01–3.97, p = 0.047).

Duration of headache episodes was not found to be related to gender, ADHD or academic performance. However, children with headache episodes that lasted over 4 hours had more learning disabilities and lower grades at school than did children with shorter duration of headaches (p = 0.027, and p = 0.042, respectively).

Leviton [23] was one of the first to report that out of 150 elementary-school children who were referred to his clinic due to recurrent headaches, approximately 40% had academic difficulties. These results are also in accordance with other recent studies that found a significant higher incidence of hyperactivity and impulsivity symptoms in children with headache, compared with healthy peers [11, 24]. In a population-based study on healthy 4–17-years old children that was conducted by Strine et al. [10], children with frequent headaches were 2.6 times more likely to have inattention and hyperactivity. Yet, the association between ADHD and headache type remains controversial. Villa et. al. [25] described impaired visual attention in children with migraine, and suggested that it depends on neurotransmitters such as dopamine and noradrenalin. These same neurotransmitters are involved in the pathophysiology of migraine; therefore they suggested it may dispose those children to attention deficit. In recent studies by Riva [26, 27] a significant association between attention related problems and headaches was demonstrated in both conditions-migraine and tension type headache. Some authors suggested that migraine and tension headache form a continuum that may share the same pathophysiological mechanisms and that the cerebral circuits subserving headache, personality profile, and attention-may overlap [28].

In accordance with other studies [16] we found a higher incidence of ADHD and lower school achievements in children with tension type headache in comparison with children with migraine. One possible explanation is that low school achievements and symptoms such as inattention, hyperactivity and impulsivity, which often accompany learning difficulties, may be associated with stress in the family, with peers, and in school, each stress may in turn contribute to symptoms of tension type headache.

A different hypothesis is that frequent headaches by themselves may increase distractibility and irritation especially in children with a primary short attention span, and thus impose a further insult on the challenge of learning. A third hypothesis is that a common disorder underlies both conditions: ADHD and headaches. The two latter theories are supported by a study that found correlation between neuropsychological defects and frequency of headache episodes [29]. In addition, children with frequent, severe headaches were more likely to exhibit high level of emotional, conduct, attention, language and peer problems, and were significantly more likely to have their disabilities interfere classroom learning and leisure activities [15]. However one should note, that since ADHD is more prevalent in boys than in girls, and since there were more boys in the group with tension type headaches-it is expected that ADHD would be more prevalent in the TTH group. Yet the gender difference was not enough to statistically explain the difference between the migraine and the TTH groups regarding ADHD prevalence and low school performance.

Higher rates of learning disabilities (24.7%) were found in our study group compared with the reported rates in the general population of Israel [22]. Learning disabilities were more prevalent in children with migraine compared to children with tension type headache, in children with long duration of headache and among children with more than 10 episodes of headache per month. Only few studies addressed the relations between learning disabilities and headaches in children. D’Andrea and Waldie [30, 31] both reported impairment in memory, visual-motor integration and poor verbal abilities, with normal performance in reading, arithmetic or motor and spatial tasks in children with migraine. Haverkamp compared the cognitive performance of children with migraine to their healthy siblings, and found no significant difference in sequential and simultaneous information processing [32]. A possible explanation to our findings is the theory of fear of failure that was found in children with chronic headaches, and as a result an over achievement approach to school work. Greater motivation to achieve has been reported in adolescents with headaches, with a positive interaction between desire for successes and achievements [33].

Our study has a few limitations: It was conducted on a clinical sample of children with headaches, meaning children who were referred to a specialized neurology clinic, and not on a sample of healthy children (like a school based study) that would identify children with headaches and then look into different aspects of their learning. According to Berkson’s principal [34] people who seek medical care are more likely to have more than one medical problem, therefore the relationship between two diseases should not be studied in such a population. Thus we speculate that the rates of ADHD and learning disabilities that were found in our study may be applicable to those children with headaches who seek medical care, but may be an overestimation for children with headaches that are not treated in a specialized medical facility. This limitation should not impact the relations found between headache diagnosis, characteristics and learning challenges (ADHD and learning disabilities) that were indicated in our study. More limitations to our study are the lack of a formal psychiatric assessment (though children with known psychiatric disorders were excluded from the study), and the wide age span of our subjects.