Studies of magnetic resonance images have revealed morphological disorders of the brainstem and cerebellum in autistic children and adults. When we studied development of the brainstem and cerebellum in autistic patients, we found that although the brainstem and cerebellum significantly increased in size with age in both autistic patients and controls, these structures were significantly smaller in autistic patients than in controls. The speed of development of the pons, the cerebellar vermis I-V and the cerebellar vermis VI-VII was significantly more rapid in autistic patients than in the controls. However, the speed of development of the other brain structures in the posterior fossa did not differ between autistic patients and controls. The regression intercepts of the brainstem and cerebellum as well as those of their components were significantly smaller in autistic patients than in controls. Results suggest that brainstem and vermian abnormalities in autism were due to an early insult and hypoplasia rather than to a progressive degenerative process.

Recent reports have suggested functional abnormalities of the brain stem in autistic children, and structural abnormalities have also been reported. We obtained magnetic resonance imaging (MRI) scans for 21 autistic children and compared them with 21 control MRI scans. The areas of the brain stem and cerebellar vermis were measured using midsagittal images. The brain stem and cerebellar vermis lobules VIII to X were found to be significantly smaller in autistic children. A positive correlation between the size of the brain stem and cerebellar vermis was observed in the autistic children. This correlation was not observed in the control children. This suggests that the size of the brain stem and cerebellar vermis are anatomically altered in autistic children and that growth of the brain stem and cerebellar vermis in autistic children is different from normal children.

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We performed volume-selective proton magnetic resonance spectroscopy (1H-MRS) of the brain with a 1.5 T magnet in 28 patients with autism, and compared the results with those from 28 age-matched patients with unclassified mental retardation and 25 age-matched healthy children. Peaks for N-acetylaspartate, choline and creatine, but not lactate, were observed in each group on 1H-MRS. The N-acetylaspartate/choline ratio was lower in patients with mental retardation than in patients with autism and controls (P = .05, respectively). However, there were no differences in the N-acetylaspartate/ choline ratios between patients with autism and controls, and the N-acetylaspartate/creatine and choline/creatine ratios did not differ among the three groups. These results suggest that N-acetylaspartate is decreased in patients with mental retardation and that a disorder or dysfunction of neurons in the brain exists. There also appear to be differences in the brain lesions or dysfunctions found in patients with autism and mental retardation.

SUMMARY Volume‐selective proton magnetic resonance spectroscopy (1H‐MRS) of the brain was performed with a 1.5 Tesla magnet in 47 healthy children and in six healthy adults. Peaks of N‐acetylaspartate (NAA), choline (Clio) and creatine (Cr) were observed in all cases, but a lactate peak was not observed. In the right parietal region, I H‐MRS revealed increases in the rations of NAAJCho and NAA/Cr and a decrease in Cho/Cr with advancing age. The most rapid changes were noted between one and three years of age. 1H‐MRS of the right frontal region also was performed in 21 cases (20 children and one adult). In the right frontal region, there was an increase in the ratio of NAA/Cho and a decrease in Cho/Cr with advancing age, while a developmental change was not observed in the ratio of NAA/Cr. The ratios of both NAA/Cho and NAA/Cr were lower in the right frontal region than in the right parietal region. These results show that developmental changes and regional variation of metabolites are observed in 1 H‐MRS of the brain, and need to be considered in its application. RÉSUMÉ Modifications développemental du vervain exploré par spectroscopic de résonance magnátique protonique Une spectroscopic de résonance magnétique protonique en sélection de volume (1H‐MRS) du cerveau a été réalisé avec un aimant de 1.5 tesla chez 47 enfants et six adultes, tous en bonne sante. Les pics de N‐acétylaspartate (NAA), choline (Cho) et créatine (Cr) furent observés dans tous les cas mais il ne fut pas observé de pic de lactate. Dans la région pariétale droite, l' 1 H‐MRS révéla un accroissement des rapports NAA/Cho et NAA/Cr. et une diminution du rapport Cho/Cr avec l'avance en àge. Les modifications les plus rapides furent notées entre un et trois ans. Une 1 H‐MRS de la région frontale droite fut aussi effectuée dans 21 cas (20 enfants et un adulte). Dans la region frontale droite, il y avait un accroissement avec l'âge du rapport NAA/Cho et une diminution du rapport Cho/Cr, sans modification developpemcntale du rapport NAA/Cr. Les rapports NAA/Cho et NAA/Cr étaient tous les deux plus faibles dans la region frontale droite que dans la région pariétale droite. Ces résultats démontrent que des modifications développemeniales et des variations régionales de métabolites sont observées dans l' 1H‐MRS du cerveau et doivent être prises en compte. ZUSAMMENFASSUNG Untersuchungen von Hintveranderungen mit der magnetischen Pmtonenresonnanzspcktroskopie Volumenselektive magnetische Protonenresonnanzspektroskopie (1H‐MRS) des Gehirns mit einem 1.5 Tesla Magneten wurde bei 47 gesunden Kindern und sechs gesunden Erwachsenen durchgeführt. Bei alien Probanden wurden Ausschlägc für N‐Azetylaspartat (NAA), Cholin (Cho) und Kreatin (Cr) beobachtet, jedoch kein Laktat Ausschlag. In der rechten Parietalregion zeigte die 1H‐MRS mit fortschreitendem Alter eine Zunahme der Verhältnis.se von NAA/Cho und NAA/Cr und eine Abnahme von Cho/Cr. Zwischen dem ersten und dem dritten Lebensjahr wurden die schnellsten Veränderungen beobachtet. Bei 21 Probanden (20 Kinder u...