Assessment of white matter microstructure integrity in subacute postconcussive vestibular dysfunction using NODDI

Area of Science:

• Neuroimaging
• Neuroscience
• Traumatic Brain Injury Research

Background:

• Vestibular symptoms like dizziness and balance issues are common after mild traumatic brain injury (mTBI).
• The neuroanatomical basis of postconcussive vestibular dysfunction (PCVD) remains unclear, hindering effective recovery.
• Subacute assessment is crucial for understanding injury response versus pre-existing vulnerabilities.

Purpose of the Study:

• To investigate white matter microstructural integrity in individuals with PCVD using advanced diffusion MRI (dMRI).
• To correlate diffusion metrics with clinical vestibular assessments in the subacute phase post-mTBI.

Main Methods:

• Utilized diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) on 23 individuals with subacute PCVD and 37 controls.
• Conducted voxelwise analysis of white matter differences and examined correlations between diffusion metrics and clinical vestibular measures.
• Assessed self-reported outcomes and objective vestibular function using standardized tests.

Main Results:

• Found significantly higher intra-neurite volume fraction (VIn) and isotropic volume fraction (VIso) in PCVD subjects compared to controls.
• These differences were localized to the left superior longitudinal fasciculus (SLF), superior corona radiata (SCR), and posterior corona radiata (PCR).
• Correlations between diffusion metrics (excluding DA) and clinical vestibular measures were significant across multiple regions of interest.

Conclusions:

• Neuroimaging reveals distinct white matter alterations in the subacute phase of PCVD.
• These microstructural changes in specific white matter tracts may underlie sensory processing deficits in PCVD.
• Further research is needed to determine if these findings represent injury response or pre-existing vulnerabilities.