Abstract
Unilateral spatial neglect (USN) is a relatively common neurological disorder observed in patients after brain injury. Patients fail to attend to the contralesional side of space (1). Although USN is well documented in adults, it has been rarely reported in children (2-10). We present a child showing USN during an attack of hemiplegic migraine, without structural brain injury. The present report is the first in which USN during migraine is described.
Case report
A right-handed 13-year-old girl was admitted to our hospital because of vomiting and right occipital headache following a flickering light and blurred vision in the left visual field. She had suffered from three episodes of headache since the age of 11 years. The headaches were pulsatile and accompanied with unilateral sensory and motor symptoms. Her parents reported that she had suffered from neither neurological nor attentional disorders other than headaches. Family members were reported to be free of hemiplegic migraine. On admission, a clinical examination showed a mild left hemiparesis, left hemihypesthesia, and dysarthria. Her consciousness was clear. Although dysarthria was observed, the patient could speak accurately with proper content. The cranial nerves were unimpaired, and her ocular movement was normal. Her visual fields could not be examined intensively because of her lack of cooperation during the headache episode. Ataxia was not observed. She often collided with obstacles on her left side. We then administered a neglect test, and left neglect in drawing was observed (Fig. 1a, b). The patient had no evidence of other cognitive symptoms. An electroencephalography (EEG) showed slow waves on the right side (Fig. 2). No epileptic discharge was revealed on the EEG. A computed tomography, a magnetic resonance imaging including T2 and diffusion-weighted imaging, and a magnetic resonance angiography indicated no structural brain abnormality. All symptoms disappeared within 24 h. She could copy a picture of a flower well at 24 h after the onset (Fig. 1c). No indices of USN other than the drawing were obtained in this case. The USN disappeared very quickly so that we were not ready in time to undergo another battery of tests. A follow-up EEG showed a disappearance of the slowing.
Drawing tests. Direct copying of the template. (a) Template. (b) At 18 h after the onset. (c) At 24 h after the onset. In (b), note the omission of petals on the left side during the migraine attack. The examiner suggested that something must be wrong, but the patient insisted that nothing was wrong. No omission of petals is shown in (c), drawn after the migraine had subsided.
Electroencephalography at 17 h after the onset. Slow waves are shown on the right side, dominantly over the posterior region. Occipital alpha rhythm is clearly present on the left side. Monopolar lead (a). Bipolar lead (b).
Discussion
USN is a common consequence of acquired brain damage (1). USN without brain damage has not been documented in adulthood. On the other hand, there has been a small amount of literature describing USN without brain injury in childhood (5, 6, 10). Nigg et al. (5) found that boys with attention deficit hyperactivity disorder (ADHD) reacted more slowly to targets in the left visual field than in the right field. Sheppard et al. (6) revealed a significant right bias of children with ADHD in the line bisection task. Dobler et al. (10) described a 7-year-old boy with sustained attention problems who showed neglect of left space. All these children had been suffering from attentional disorders, and had no structural brain damage. Thus there is some evidence that unilateral neglect can occur in children with ADHD. On the other hand, our patient had no history of attentional disorder. The pathophysiology of USN in the present patient may be different from that in ADHD children.
In adulthood, USN can be found after either right or left hemisphere damage. Contralateral neglect is markedly more severe following right hemisphere injury (11). In childhood, USN has been reported also after injuries in both hemispheres (8, 9), and left spatial neglect with right hemisphere damage has been more frequently documented (2, 4, 7–9). Although no structural brain damage was revealed in our patient, the EEG demonstrated a slowing on the right side, which represented dysfunction of the right hemisphere. Thus our patient showed left spatial neglect with dysfunction of the right hemisphere. The laterality of spatial neglect in our patient was consistent with previous reports.
Our patient had left motor weakness and left sensory disturbance during an attack of headache on the right side. No family history was reported. Thus the diagnosis was consistent with sporadic hemiplegic migraine (SHM) (12, 13). Although dysarthria was observed, a diagnosis of basilar migraine was denied because of the absence of brain stem symptoms: vertigo, ataxia, diplopia, and a reduced level of consciousness. Thomsen et al. (12) found that 72% of patients with SHM fulfilled the criteria for basilar migraine during SHM attacks and recommended that cases with motor weakness and basilar type symptoms be diagnosed as hemiplegic migraine (13). Thus the presence of dysarthria in our patient does not annul the diagnosis of hemiplegic migraine. For our patient, this was the fourth attack of hemiplegic migraine. No information was obtained about the laterality of motor and sensory symptoms during the prior attacks, and we could not know whether the side of prodromes shifted from attack to attack.
Hills et al. (14) have shown that patients with subcortical strokes have neglect because of cortical hypoperfusion, and revealed a significant correlation between volume of perfusion-weighted imaging (PWI) abnormality and neglect battery scores (15). Thus PWI has potential but was not performed on our patient. During the migraine, left spatial neglect may be attributed to the cortical hypoperfusion that is developed transiently on the right hemisphere. The severity of neglect depends on the volume of hypoperfusion (15). Two of three petals on the left side were omitted in our patient. All petals would be omitted in a more severe situation. Our patient is considered to have moderate degree of neglect.
USN in our patient persisted only during the acute stage of migraine and disappeared quickly and completely. It lasted for only 24 h. In childhood, the duration of neglect has been documented to range widely. Trauner (9) found that neglect could be present for up to 6 years. Ferro et al. (2) reported the duration to be shorter (2 weeks to 1 month) and noted that the neglect may be overlooked if not searched for during the acute stage. The duration of 24 h is the shortest found in the literature. Whether in childhood or in adulthood, USN during a migraine attack has not been described. This case indicates that USN can occur transiently during an attack of hemiplegic migraine and can be diagnosed if under careful observation. Furthermore, it is noteworthy that USN can develop without structural brain damage.