Diffusion tensor imaging and cognitive speed in children with multiple sclerosis

Area of Science:

• Neuroimaging
• Pediatric Neurology
• Neuroscience

Background:

• Multiple sclerosis (MS) is a demyelinating disease affecting the central nervous system.
• Early detection of white matter (WM) integrity changes in pediatric MS is crucial for understanding disease progression and long-term outcomes.
• Diffusion tensor imaging (DTI) offers a non-invasive method to assess WM microstructure.

Purpose of the Study:

• To compare WM integrity between children with MS and healthy controls using DTI.
• To investigate the correlation between DTI findings, disease activity (lesion burden), and cognitive processing speed in pediatric MS.
• To determine if DTI can detect early microstructural changes in normal-appearing white matter (NAWM) in children with MS.

Main Methods:

• DTI parameters, including fractional anisotropy (FA) and mean diffusivity (MD), were measured in NAWM regions (corpus callosum, hemispheric lobes, thalamus) of 33 children with MS and 30 healthy controls.
• T2 lesion volumes and Expanded Disability Status Scale (EDSS) scores were assessed in MS patients.
• Cognitive processing speed was evaluated using the Visual Matching and Symbol Digit Modalities Test (SDMT).

Main Results:

• Children with MS exhibited significantly lower FA values in the corpus callosum (genu, splenium) and hemispheric NAWM (parietal, temporal, occipital lobes) compared to controls.
• No significant differences in FA or MD were found in the thalamus between groups.
• Higher T2 lesion volumes correlated with reduced FA in the corpus callosum and hemispheric NAWM; however, DTI metrics did not correlate with EDSS scores.
• Reduced FA in corpus callosum regions was associated with slower cognitive processing speed (Visual Matching and SDMT) in MS participants.

Conclusions:

• DTI reveals widespread microstructural abnormalities in NAWM of children with MS, indicating early tissue pathology.
• The degree of NAWM disruption in pediatric MS correlates with impaired cognitive processing speed.
• These findings highlight the functional consequences of early MS-related tissue damage and support the utility of DTI in assessing disease impact in children.