Abstracts

Rationale: PNES (psychogenic non-epileptic seizures) are characterized by global, multifocal abnormalities in brain function and connectivity. Few studies have examined the link between brain structure and function in PNES. Since up to 83% of patients with PNES report prior traumatic brain injury (TBI), TBI may be a key component of PNES pathophysiology. This study investigated TBI patients with and without PNES to identify grey matter volume (GMV) and cortical morphology abnormalities associated with PNES.

Methods: Adults diagnosed with PNES+TBI (N=62) or TBI-only (N=59) were imaged using 3T MRI. Electronic medical record reviews and video-electroencephalograms were consulted for definitive diagnosis of TBI and PNES. High-resolution T1W anatomical scans (0.8 mm isotropic) were analyzed by voxel- and surface-based morphometry. Voxelwise general linear models computed group differences in GMV and cortical morphology (thickness, sulcal depth, fractal dimension, and gyrification), which were assessed with permutation-based testing with the Threshold-Free Cluster Enhancement toolbox. Logarithmically scaled p-values were considered significant at p< 0.05, corrected for multiple comparisons using family-wise error.

Anxiety and depression were measured with the Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI), respectively. The Symptom Checklist-90-Revised instrument assessed global severity (SCL-90-R GSI) and somatization of psychological symptoms (SCL-90-R SOM). The Global Assessment of Functioning (GAF) scale measured the impact of participants’ symptoms on psychological, social, and occupational functioning.

Results: There were no differences between groups in TBI characteristics and proportions of mild/moderate/severe TBI. PNES+TBI participants had significantly lower GAF scores (p< 0.0001), higher SCL-90-R GSI and SOM scores (p< 0.001), higher BDI scores (p< 0.0001), and higher BAI scores (p< 0.0001) (Table 1). Relative to TBI-only, the PNES+TBI group demonstrated atrophy of the left inferior frontal gyrus (L IFG) and the right (R) cerebellum VIII (Fig.1A). PNES+TBI participants also had decreased sulcal depth (p_FWE< 0.05) in the left insular cortex and overlapping regions (Fig.1B) and decreased fractal dimension in the R superior parietal gyrus (Fig.1C). All significant clusters correlated positively with GAF scores. Brain atrophy in the L IFG and cerebellum were associated with higher BAI and BDI scores, while decreased sulcal depth was associated with anxiety scores.