Cortical thickness and gyrification patterns in patients with psychogenic non-epileptic seizures

Abstract

Psychogenic non-epileptic seizures (PNES) are often viewed as manifestations of altered motor and sensory function resulting from psychological responses to adverse experiences. Yet many patients and non-expert healthcare professionals find it difficult to understand how severe disturbances in normal neurological functioning can solely result from underlying psychological mechanisms to the exclusion of other physical causes. Perhaps importantly, recent advances using neuroimaging techniques point to possible structural and functional correlates in PNES. In an attempt to further our understanding of the neurobiological correlates of this condition, we compared the brain scans of 20 patients with PNES (14 females, mean age 41.05, range 19-62) and 20 age- and gender-matched healthy controls (14 females, mean age 40.65, range 21-61) to investigate group differences for cortical thickness and gyrification patterns using FreeSurfer. Compared to controls, patients with PNES showed cortical thickness increases in motor, sensory and occipital areas as well as cortical thickness decreases in temporal and frontal brain regions. In addition, we observed age-related changes in cortical thickness in the right lateral occipital area in PNES. However, contrary to our prediction that atypical gyrification may be present, we did not find any evidence of abnormalities on a measure thought to reflect prenatal and early childhood cortical development and organization. Nor did we find significant correlations between cortical thickness results and clinical features. These findings partly corroborate, but also differ from previous morphometric studies in PNES. These inconsistencies likely reflect the aetiology and phenomenological heterogeneity of PNES.

<p>Widely Impaired White Matter Integrity and Altered Structural Brain Networks in Psychogenic Non-Epileptic Seizures</p>

“…Compared with DTI studies, there have been a greater number of morphological statistical neuroimaging studies of PNES. [29][30][31][32][33] In general, PNES shows frontal and temporal lobar abnormalities in gray matter volume or cortical thickness, although there are some inconsistencies. These areas are also related to normal aging during young adulthood to middle age, 34 which may explain the faster brain aging in patients with PNES.…”

Structural alterations in functional neurological disorder and related conditions: a software and hardware problem?

“…Individuals with PNES also exhibited bilateral precentral and right entorhinal and lateral occipital cortical thinning; between-group sulcal depth abnormalities are described in Table 1. Another CTH and gyrification study in 20 patients with PNES showed reduced bilateral inferior frontal and right superior temporal and medial orbitofrontal CTH compared to controls; this PNES cohort also showed increased CTH in bilateral cuneus and left paracentral and lingual regions (McSweeney et al, 2018). There were no between-group gyrification differences.…”

“…Overall, while the directionality of effects requires clarification, early evidence suggests that individual differences in caudal ACC and inferior frontal gyrus CTH in FND may be linked to somatoform dissociation (Labate et al, 2011; McSweeney et al, 2018; Perez et al, 2018b; Vasta et al, 2018). Notably, the ACC and inferior frontal gyrus are implicated in attentional/cognitive control and self-monitoring, and the caudal ACC is an integrative zone for cognitive control, negative affect and nociception (Shackman et al, 2011).…”

“…Notably, the ACC and inferior frontal gyrus are implicated in attentional/cognitive control and self-monitoring, and the caudal ACC is an integrative zone for cognitive control, negative affect and nociception (Shackman et al, 2011). Furthermore, CTH studies have been inconsistent in delineating possible motor/premotor/SMA alterations, with studies reporting reduced (Labate et al, 2011; Ristic et al, 2015), increased (McSweeney et al, 2018) or no group-level CTH differences (Aybek et al, 2014a; Perez et al, 2018b); sensorimotor cortical thinning was also observed in somatoform pain disorder (Magon et al, 2018).…”

“…Increases in premotor CTH and SMA volume have been identified in hemi-paretic FND-limb weakness (Aybek et al, 2014a) and mixed-FND pediatric (Kozlowska et al, 2017) populations, respectively. However, both decreases and increases in motor-related GM have been observed in patients with PNES (Labate et al, 2011; McSweeney et al, 2018; Ristic et al, 2015). These observations suggest heterogeneity in the magnitude and direction of potential motor alterations, even within specific FND subtypes.…”