Psychophysiological mechanisms underlying spatial attention in children with primary headache

Abstract

Objective

Neurophysiological studies to evaluate spatial attention in children with primary headache are lacking. Tactile spatial attention modulates the N140 somatosensory evoked potential (SEP) amplitude.

The aims of the study are: (1) to investigate the effect of spatial attention on the N140 amplitude in children with migraine and tension-type headache (TTH) and in healthy children, and (2) to correlate the neurophysiological results with a neuropsychological test for spatial attention.

Methods

We studied 16 patients with migraine without aura (MoA), 12 TTH children and 10 healthy subjects. “Deux Barrage” test for spatial attention was administered. SEPs were recorded in a neutral condition (NC) and in a spatial attention condition (SAC).

Results

No significant differences in neuropsychological measures were found between MoA, TTH and healthy subjects. The N140 amplitude increase during SAC, as compared to NC, was significantly higher in patients than in healthy controls. Migraineurs showed a positive correlation between the N140 amplitude increase during SAC and their neuropsychological performance.

Conclusions

Although spatial attention performances in children with headache are as good as in controls, the N140 amplitude increase during SAC in headache patients suggests that the psychophysiological mechanisms subtending spatial attention are different from those in healthy children.

Introduction

Headache is the most frequent neurological symptom and commonest manifestation of pain in childhood [1]. Studies have reported annual prevalence rates in children of 3–11% for migraine and 0.9–24% for tension-type headache (see [2] for a review). The negative consequences of headache in childhood and adolescence are often underestimated. Several neuropsychological studies were dedicated to the investigation of the effects of migraine on the cognitive functions especially in adult patients. Some researchers have reported that migraineurs have cognitive deficits [3], [4], [5]. The functions most often affected are memory, information speed processing, attention [5], and verbal and psychomotor ability [4]. Cognitive impairments observed in migraineurs have been found to occur during a migraine attack, after the attack, and even when the individual does not exhibit any residual effects of the attack [6]. However, there is no agreement, since other studies have found a normal cognitive performance in migraine patients [7]. Moreover, there is empirical evidence that patients with migraine, including those with aura, do not have a risk of long-term neuropsychological impairment [8].

As for the developmental age, there are only a few studies assessing the impact of migraine on neurocognitive performance and their results are often in disagreement [9], [10], [11], [12].

Somatosensory evoked potentials (SEPs) have been used to investigate the effect of spatial attention on the tactile information processing. In most studies, SEPs were recorded to electrical stimuli delivered to one hand, while the subject was asked to focus his/her attention onto the designated hand (ipsilateral or contralateral to the stimulated hand) [13], [14]. A consistent finding from these experiments is that tactile spatial attention modulates the somatosensory N140 component, with increased N140 amplitude evoked by electrical stimuli delivered to the attended hand [15]. Garcia-Larrea et al. [14] demonstrated that the N140 potential is identifiable at Cz vertex only when subject’s attention is addressed toward somatosensory stimuli delivered in the same area of the stimulated median nerve. Thus, according to this study, the N140 response is fully endogenous and requires the attentional involvement of the subject. The N140 SEP component has never been investigated in migraineurs in order to evaluate the psychophysiological mechanisms subtending spatial attention.

The present study had two main aims. First, we investigated the spatial attention in children with migraine and with tension-type headache, as compared with healthy children, using two measures: (1) the amplitude and latency modifications of the N140 SEP component during a spatial attention task, and (2) the performance in a neuropsychological test (“Deux Barrage” test) evaluating spatial attention. Second, we searched for correlations between the neurophysiological results and the scores obtained from the neuropsychological test, in order to explain the meaning of possible differences in the psychophysiological mechanisms underlying spatial attention between headache and non-headache children.