Reduced gray matter volume in the frontotemporal cortex of patients with early subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis (SSPE) is a persistent infection of the central nervous system by the measles virus. Patients in the initial stages of SSPE show behavioral symptoms and usually normal cranial MR imaging findings. We aimed to investigate the gray matter volume changes in patients with early SSPE.

Seventeen patients with SSPE with normal cranial MR imaging findings and 30 sex- and age-matched control subjects were included in the study. Clinical parameters of the patients were quantified by using a neurologic disability index (NDI) as defined previously. We obtained T1-weighted magnetization-prepared rapid acquisition gradient echo images from the patients and control subjects, and we applied an optimized method of voxel-based morphometry. We performed a cross-sectional analysis to search the gray matter volume differences between the patients and control subjects. The correlation between the gray matter distribution and the duration of symptoms, immunoglobulin G index, and NDI scores was tested.

We found that the cortical gray matter volume of patients was reduced in the frontotemporal regions including the bilateral cingulate cortex and amygdala. There was no correlation between the gray matter distribution of patients and the duration of symptoms or the NDI scores.

The current study demonstrated gray matter volume reduction in the frontotemporal cortex of patients with SSPE without any apparent lesions on conventional MR imaging. Because the cingulate cortex and amygdala are involved in emotion processing, gray matter loss in these regions may contribute to the development of early behavioral symptoms of SSPE.