Neuroimaging studies in patients with psychogenic non-epileptic seizures: A systematic meta-review

Abstract

Psychogenic Non-epileptic Seizures (PNES) are ‘medically unexplained’ seizure-like episodes which superficially resemble epileptic seizures but which are not caused by epileptiform discharges in the brain. While many experts see PNES disorder as a multifactorial biopsychosocial condition, little is known about the neurobiological processes which may predispose, precipitate and/or perpetuate PNES symptomology. This systematic meta-review advances our knowledge and understanding of the neurobiological correlates of PNES by providing an up-to-date assessment of neuroimaging studies performed on individuals with PNES. Although the results presented appear inconclusive, they are consistent with an association between structural and functional brain abnormalities and PNES. These findings have implications for the way in which we think about this “medically unexplained” disorder and how we communicate the diagnosis to patients. However, it is also evident that neuroimaging studies in this area suffer from a number of significant limitations and future larger studies will need to better address these if we are to improve our understanding of the neurobiological correlates of predisposition to and/or manifestation of PNES.

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

“…We found widespread FA and MD abnormalities as well as impaired brain networks including increased path length, decreased network efficiency, altered nodal topology, and reduced network connectivity. Considering the need for additional evidence from neuroimaging, 4 our findings may contribute to the neurobiological understanding of PNES.…”

“…In addition, to fully reveal the effects of PNES, another group of controls (e.g., psychiatric patients without PNES) might have been valuable, as suggested in a previous paper. 4 Thus, more comprehensive and multicohort studies with larger sample sizes are desirable. Additionally, more high-precision imaging protocols should be needed, considering the relatively low number of DTI directions in this study (i.e.…”

“…1,2 While the underlying mechanism of PNES would be different from that of epilepsy, improved neurobiological knowledge of PNES will be helpful for both treatment and patients' understanding of their own illness. 3,4 Although neuroimaging studies are expected to provide relevant information and insights about the mechanisms, there are still a limited number of papers. 4 Additionally, the social and medical environments of PNES vary widely around the world 1 and, similarly, the potential causes of PNES, such as abuse or family conflict, are also dependent on background cultures.…”

“…3,4 Although neuroimaging studies are expected to provide relevant information and insights about the mechanisms, there are still a limited number of papers. 4 Additionally, the social and medical environments of PNES vary widely around the world 1 and, similarly, the potential causes of PNES, such as abuse or family conflict, are also dependent on background cultures. 2 Thus, further accumulation of evidence on neurobiological aspects of PNES from various cultures may contribute to better understanding and clinical practice in this field.…”

The aetiology of psychogenic non‐epileptic seizures: risk factors and comorbidities

“…These effects on frontolimbic structures may be aggravated by reduced functional connectivity between limbic and prefrontal areas as well as increased amygdala reactivity to negative stimuli (Herringa, 2017). Although imaging studies in patients with PNES have so far failed to converge on pathognomonic structural abnormalities across unselected PNES patient populations (Asadi-Pooya, 2015;McSweeney et al, 2017), altered structural frontolimbic connectivity has been demonstrated in some cases (Hernando et al, 2015;Perez et al, 2017), possibly related to disruption of age-dependent maturation processes (Popkirov et al, 2018a). The long-term developmental effects of childhood trauma also include changes in various developmentally sensitive allostatic systems relevant to PNES and related disorders (Keynejad et al, 2018).…”