To determine whether previously reported areas of increased T2 signal intensity on MRI examination in children with neurofibromatosis type 1 (NF 1) are associated with deficits in development and learning common in this population, we evaluated 51 children with NF 1 (aged 8 to 16 years). Forty children completed the full assessment protocol (MRI, medical, psychometric, speech therapy, and occupational therapy assessments). The mean Full Scale IQ scores for the entire study population showed a left shift compared with the normal population, and the distribution of IQ scores was bimodal, suggesting that there are two populations of patients with NF 1--those with and those without a variable degree of cognitive impairment. There was no association between lower IQ scores and any clinical variable. Areas of increased T2 signal intensity unidentified bright objects (UBO+) were present in 62.5% of the study population, and their presence was not related to clinical severity, sex, age, socioeconomic status, macrocephaly, or family history of NF 1. However, compared with children without areas of increased T2 signal intensity (UBO-), the UBO+ group had significantly lower mean values for IQ and language scores and significantly impaired visuomotor integration and coordination. Children with areas of increased T2 signal intensity were at a much higher risk for impaired academic achievement. Children without increased T2 signal on MRI (UBO-) did not significantly differ from the general population in any measure of ability or performance. Areas of increased T2 signal on MRI represent dysplastic glial proliferation and aberrant myelination in the developing brain and are associated with deficits in higher cognitive function.(ABSTRACT TRUNCATED AT 250 WORDS)

SUMMARY The authors evaluated 51 consecutive children with NF1 (aged eight to 16 years) to determine the frequency of intelectual impairment and learning disability due to NF1 alone, the profile of learning disabilities and the effect of clinical variables. 40 children completed the full assessment protocol. There was no support for a profile of predominantly visuoperceptual deficits in the NH population. There was no discrepancy between verbal and performance 1Q, and the deficits in function were wide ranging. Clinical variables such as age, sex. socio‐economic status, disease severity, macrocephaly and family history of NF1 were not associated with cognitive deficits. These results emphasise the need for developmental evaluation to be included in the routine assessment of children with NFT. RÉSUMÉ Difficultés spécifiques d'apprentissagc chez les enfants porteurs de neurofibromatose Les auteurs ont étudié consécutivement 51 enfants avec NFI (âgés de huit à 16 ans) pour préciser la fréquence des troubles intellectucls ei les difficultés d'apprentissage dûs à la seule NFI, le profile des difficultés d'apprentissage et l'effet des variables cliniques. Une évaluation complète fut conduite chez 40 enfants. II n'a pas été relevé dans la population NFI de données favorisant un profile marqué par un déficit visuoperceptif prédominant. II n'y avait pas de différence entre les échelles de QI verbal et performance ct le doniaine des déficits fonctionnels était très étendu. Les variables cliniques telles que l'âge, le sexe. la classe socio‐économique, la gravité de l'affection, la macrocéphalic et l'histoire familiale de NFI n'étaient pas associées à des déficits cognitifs. Ces résultats soulignent la nécessité d'inclure une évaluation du développement dans la surveillance de routine des enfants NFL ZUSAMMENFASSUNG Spezifische Lernprobleme bei Kindern mit Neurofibroinatose Die Autoren untersuchten 51 Kinder mil NFI (Alter acht bis 16 Jahre), urn die Häufigkeit von intellektuellen Störungen und Lernproblemen durch NFI allein, das Profil der Lernprobleme und den Einfluh klinischer Variablen zu beurteilen. 40 Kinder haben das gesamte Untaersuchungsprotokoll beendet. Bet den NFI Patienten fand sich kein Hinweis für spezifische Störungen der visuellen Perzeption. Es gab keinen Unterschied zwischen dem verbalen‐ und dem Handlungs‐IQ und die Funktionsausfälle waren weit gestreut. Die klinischen Variablen wie Alter, Geschlecht, sozioökonomischcr Status. Schweregrad der Erkrankung, Makrozephalie und Familienanamnese für NFI standen nicht im Zusammenhang mit kognilivcn Störungen. Durch diese Ergebnisse wird die Notwendigkeit einer Beurteilung der Entwicklung bei den Routineuntersuchungen von kindern mit NFI deutlich. RESUMEN Alteración espeeifica del aprendizaje en niños con neurofibromatosis Los autores evaiuaron 51 niños consecutivos con NF‐1 (de ocho a 16 años de edad) para determinar la frecuencia de la alteración intelectual y del aprendizaje y el e fee to de variables clínicas. 40 niños cumplieron con todo el protocolo. No se ...

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