Neuropsychological significance of areas of high signal intensity on brain MRIs of children with neurofibromatosis

Abstract

Of children with neurofibromatosis (NF), 40% have a cognitive or learning impairment. Approximately 60% also have anomalous areas of high signal intensity on T2-weighted brain MRIs. The association of these hyperintensities and neuropsychological status is not fully understood. We administered a battery of neuropsychological tests and a standard clinical MRI to determine the impact of hyperintensity presence, number, and location on cognitive status in 84 children (8 to 16 years) with NF type 1. These children underwent standard clinical MRI using a GE 1.5-tesla scanner (except one child who was examined with a 1.0-tesla scanner). We conducted three types of analyses: Hyperintensity presence or absence.-Scores of children with (55%) and without hyperintensities (45%) were compared using t tests. No statistically significant differences between groups in intellectual functioning or any neuropsychological variable were found. Number of hyperintensities-The number of hyperintensity locations per child ranged from one to five (mean = 2.22). Pearson correlations revealed no significant association between the number of hyperintensities and neuropsychological performance. Location of hyperintensities-In four of the five locations studied, no statistically significant differences were found between scores of children with a hyperintensity in an area and those with one elsewhere. However, mean scores for IQ, Memory, Motor, Distractibility, and Attention domains for children with hyperintensities in the thalamus were significantly lower than scores for those with hyperintensities elsewhere. These results suggest that the simple presence or absence of hyperintensities, or their total number, is not as important as their anatomic location for detecting their relationship with neuropsychological status. Taking location into account, hyperintensities in the cerebral hemispheres, basal ganglia, brainstem, or cerebellum seem to have no impact on neuropsychological functioning, whereas hyperintensities in the thalamus do.

High frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis in Brazilian patients with neurofibromatosis type 1

“…Fifteen patients refused the IQ tests. Other studies have reported mental retardation frequencies ranging from 3 to 14% (12,15,(26)(27)(28)(29)(30)(31)(32)(33). Learning difficulties were also reported in 38 of 50 (76%) patients in our study, a value higher than the percentage of 30-62% reported by others (13,14,16,(22)(23)(24)(26)(27)(28)(29)(30)(31)(33)(34)(35).…”

Reduced Cerebral Arterial Spin-Labeled Perfusion in Children with Neurofibromatosis Type 1

“…17,36,37 Marked reduction in CBF in the thalamus and variable alterations in cortical perfusion in our study also implicate these brain regions, potentially reflecting underlying dysgenesis or a dysfunction in their relationship, or underlying arteriopathy as a source of cognitive deficits, not unlike the adult model for vascular dementia. 38 In the present study, we used ASL perfusion to measure CBF because it directly quantifies CBF by use of in-flowing arterial protons as an endogenous tracer 39,40 and has additional advantages in children because of the high labeling efficiency and signalto-noise ratio.…”

“…[8][9][10][11] Some authors have postulated that impaired cognition may arise from unidentified bright objects (UBOs), [12][13][14] though no reliable link exists between the number of UBOs and cognitive performance. [15][16][17] Others have suggested abnormal cortical connectivity 9,10 and underlying cerebral dysgenesis 18 as sources of poor cognitive performance, whereas the relationship between NF-1 arteriopathy and cognitive impairment remains unknown. Given the lack of cerebral hemodynamic data in the setting of risks for cerebral vasculopathy and neurocognitive complications, we sought to understand cerebral perfusion patterns in children with NF-1.…”

Múltiplas hiperintensidades no sistema nervoso central em uma criança com neurofibromatose do tipo 1

“…Entretanto, alguns estudos mostram uma possível associação entre a presença dos UBOs e a disfunção cognitiva (2)(3)(4)6,(11)(12)(13) . Isso poderia acontecer especialmente na presença de envolvimento do tálamo (14)(15)(16) e, talvez, se constituísse em um bom preditor de disfunção cognitiva na idade adulta (5,17) . Outros trabalhos têm também associado os UBOs a alterações no desempenho da motricidade fina (12) .…”