Neurospectroscopy

Contribution of proton MR spectroscopy to the evaluation of children with unexplained developmental delay.

Developmental delay (DD) in children is a common socio-economic problem with a prevalence of 1 to 2%. The cause of DD in children is often unknown and MRI plays an important role in evaluating children with DD, estimating long term prognosis and guiding therapeutic options.

The aim of our study on children with DD was to elucidate: a) whether MRS reveals abnormalities in cerebral metabolism, and b) whether there is a correlation between the cognitive performance and the concentration of brain metabolites, especially N-acetylaspartate (NAA), named in the literature a neuronal marker.

Using proton MRS of deep gray and central white matter, we measured concentrations of brain metabolites in children aged one month to thirteen years with unexplained DD (DQ between <50 and 85) and normal MRI examinations, and compared them to those of age matched normal control children. Children with DD were divided into three groups: mild (DQ 76 to 85), moderate (DQ 51 to 75) and severe (DQ < 50).

We found no significant differences in metabolite concentrations, neither among the three groups of children with DD nor between patients and age matched normal control children. Independent of the degree of mental retardation, the NAA concentrations of handicapped patients and normal children were comparable.

We conclude that a) brain metabolites, especially NAA, in children with unexplained DD are within normal limits, b) in most cases, proton MRS adds little information concerning etiology of unexplained DD.

Methods

• MR: 2T scanner , 1H-MRS
• Subjects: 48 patients with mental retardation of unknown origin (3.6 ± 2.9 yrs), 23 age-matched controls (3.2 ± 3.2 yrs).

Box plots showing the different brain metabolite concentrations (median, 25th and 75th percentiles, as well as the standard deviation) in deep gray matter (right) and central white matter (left), grouped according to the severity of mental retardation in mild, moderate and severe DD.

Collaborations

Prof. Remo Largo and Dr. Susanne Ritter, Growth and Development Center, Department of Pediatrics, University Children’s Hospital Zurich

Contact

Prof. Dr. Ernst Martin
Ernst.Martinkispi.uzh.ch