Post-concussion syndrome: Correlation of neuropsychological deficits, structural lesions on magnetic resonance imaging and symptoms

Background : Post-concussion syndrome (PCS) associated with mild traumatic brain injury (MTBI) can cause long-lasting disabilities. Magnetic resonance imaging (MRI) evaluation in these patients may demonstrate structural lesions that correlate with functional deficits on neuropsychological testing. However, little is known about the significance of the relationship between structureal lesions on MRI, functional deficits on neuropsychological evaluation and outcome in patients with MTBI.
Aims: To assess neuropsychological deficits and structural lesions on MRI in patients with PCS following MTBI, and to find correlation between these findings and PCS.
Settings and Design : Prospective, observational, cohort study in a tertiary hospital.
Materials and Methods : The study cohort included consecutive patients with MTBI (three months or more duration) and PCS. All the patients in the cohort had neuropsychological testing using the National Institute of Mental Health and Neurological Sciences Neuropsychological Battery for head injury and also MRI using T1, T2 and FLAIR sequences. Statistical analysis was done using Fisher′s Exact test of significance.
Results : All the 20 patients evaluated had neuropsychological deficits. Eleven patients had lesions on MRI. Disturbances of sleep, behavior and memory and abnormalties in tests for mental speed were more frequent in patients with lesions on MRI, but were not statically significant (P=0.08). Both the test modalities localized lesions predominantly to the frontal and temporal lobes. All the symptoms observed in the patients were associated with prefrontal dysfunction on neuropsychological testing.
Conclusions : Prefrontal dysfunction is invariably associated with PCS following MTBI. Structural lesions on MRI may not always be present but when present may influence the degree or severity of the symptoms.

Keywords
Minimal traumatic brain injury, post-concussion syndrome, magnetic resonance imaging, neuropsychological deficits