Attention processes in children with shunted hydrocephalus versus attention deficit-hyperactivity disorder

Children with congenital hydrocephalus, children with attention deficit-hyperactivity disorder, and normal controls were evaluated with measures of focused attention (Visual Orienting and Detection Task), sustained attention (continuous performance test), and attention shifting (Wisconsin Card Sorting Test). Components from these tasks have been linked to attention systems mediated by anterior or posterior brain networks. Children with congenital hydrocephalus showed an inability to focus and shift attention, which specifically implicated impairment of the disengage and move components of the posterior brain attention system. Children with attention deficit-hyperactivity disorder displayed the expected performance patterns on measures of focused attention once their difficulties with sustained attention were taken into account. However, they showed problems with shifting and sustaining attention, which are commonly associated with the anterior brain attention system.

Prospective evaluation of the brain in asymptomatic children with neurofibromatosis type 1: relationship of macrocephaly to T1 relaxation changes and structural brain abnormalities

BACKGROUND AND PURPOSE

Mutation of the neurofibromatosis type 1 (NF-1) gene may be associated with abnormal growth control in the brain. Because macrocephaly could be a sign of abnormal brain development and because 30% to 50% of children with NF-1 display macrocephaly in the absence of hydrocephalus, we sought to determine the relationship between macrocephaly and other brain abnormalities in young subjects with NF-1. These subjects were free of brain tumor, epilepsy, or other obvious neurologic problems.

METHODS

We prospectively screened 18 neurologically asymptomatic subjects with NF-1, ages 6 to 16 years, using clinical measures, psychometric testing, conventional MR imaging, and quantitative MR imaging to measure T1.

RESULTS

Cranial circumference was 2 or more SDs above the age norm in seven (39%) of 18 subjects, a frequency of macrocephaly 17-fold higher than normal. Conventional MR imaging showed abnormalities in all 18 children, although there were more extensive abnormalities in subjects with macrocephaly. Macrocephaly in NF-1 was associated with enlargement of multiple brain structures, and brain T1 in macrocephalic subjects was reduced with respect to controls in the genu, frontal white matter, caudate, putamen, thalamus, and cortex. In normocephalic subjects, T1 was reduced only in the genu and splenium. Volumetric analysis showed that macrocephaly was associated specifically with enlargement of white matter volume.

CONCLUSION

Neurologically asymptomatic children with NF-1 showed macrocephaly, cognitive deficit, enlarged brain structures, and abnormally low brain T1. Macrocephaly in children with NF-1 may be associated with characteristic alterations in brain development, marked by more widespread and significant changes in T1, greater enlargement of midline structures, and greater volume of white matter.

Attention processes in children with shunted hydrocephalus versus attention deficit-hyperactivity disorder

Children with congenital hydrocephalus, children with attention deficit-hyperactivity disorder, and normal controls were evaluated with measures of focused attention (Visual Orienting and Detection Task), sustained attention (continuous performance test), and attention shifting (Wisconsin Card Sorting Test). Components from these tasks have been linked to attention systems mediated by anterior or posterior brain networks. Children with congenital hydrocephalus showed an inability to focus and shift attention, which specifically implicated impairment of the disengage and move components of the posterior brain attention system. Children with attention deficit-hyperactivity disorder displayed the expected performance patterns on measures of focused attention once their difficulties with sustained attention were taken into account. However, they showed problems with shifting and sustaining attention, which are commonly associated with the anterior brain attention system.

Learning disability subtypes in children with neurofibromatosis

A high incidence of learning disabilities (LD) has been reported in children with neurofibromatosis Type 1 (NF-1), and many children affected with this disease are thought to have a form of LD that is characterized by selective visuospatial and motor deficits. However, the evidence is subject to sampling biases and is limited by the clinical-inferential methods used to classify children into LD subtypes. In the present study, objective statistical methods were used to categorize LD in 105 children with NF-1 between the ages of 6 and 18 years. A cluster analysis of achievement test scores yielded 10 groups; 6 of which met our criterion for academic deficiency. An analysis of neuropsychological data for 72 children with academic deficiencies with complete neuropsychological data yielded three groups: a neuropsychologically normal group (n = 28), a group with general academic deficiencies (n = 34), and a group with visuospatial-construction deficiencies (n = 10). The low incidence of visuospatial-constructional deficits and the absence of cases involving pure linguistic deficits is notable.