Utilization of brain imaging in evaluating patients with psychogenic nonepileptic spells

Psychogenic nonepileptic spells (PNES) are paroxysmal movements or sensory events that resemble epileptic seizures but lack corresponding ictal electrographic changes. A confirmed diagnosis of PNES is only accomplished via video electroencephalogram (vEEG) monitoring. Prior to diagnosis, patients are often assessed with neurodiagnostic imaging and their conditions treated with anticonvulsant medications, both of which are of limited clinical value and contribute to the higher cost of care. In this study, we assessed the relationship between the semiological features of PNES, medication regimen, or psychiatric comorbidities and the frequency of referrals for brain imaging tests prior to diagnosis of PNES.

This is a retrospective chart review of 224 adult patients diagnosed as having PNES at a level 4 epilepsy care center from 2012 to 2017. Patients with coexisting epilepsy were excluded. The 882 segments of vEEG records were reviewed for semiology of spells, and patients were categorized into one of seven distinct phenotypic classes according to the accepted clinical classification. The frequency of neurodiagnostic tests completed for each patient prior to vEEG was correlated with PNES phenotype and other clinical characteristics.

There were 68 (30%) males and 156 (70%) females diagnosed as having PNES with a median age of 36 years. Seventy-four percent of patients were receiving one or several anticonvulsant medications, and 67% of patients were treated with psychotropic medications other than benzodiazepines. The most prevalent PNES events were characterized by semirhythmic small amplitude movements in the extremities (class 2; 34%) followed by those resembling tonic-clonic seizures (class 4; 28%). Neurodiagnostic imaging tests including computed tomography (CT) and magnetic resonance imaging (MRI) of the brain were performed at least once in 60% of patients and 4 times or more in 11% prior to vEEG. There was a significant association between the frequency of neurodiagnostic tests and the PNES phenotype (p = 0.02). Specifically, patients with sensory changes (class 6) had more imaging tests than those with primitive gesturing and truncal posturing (classes 1 and 5, respectively). Additionally, patients diagnosed with 3 or more psychiatric disorders underwent significantly more neurodiagnostic tests relative to patients diagnosed with two or fewer psychiatric disorders (p = 0.03). Furthermore, patients whose conditions were treated with anticonvulsant medications tended to undergo more imaging scans prior to vEEG as compared with the patients whose conditions were not being treated with anticonvulsants.

These findings suggest that the frequency of brain imaging obtained prior to the definitive diagnosis of PNES is influenced by semiology of spells and the psychiatric health of patients. Patients who demonstrate minimal paroxysmal movements in the settings of multiple psychiatric comorbidities represent a particularly challenging patient phenotype which is linked to more frequent referrals for brain imaging. These patients should be promptly referred for vEEG to improve diagnostic accuracy and prevent treatment with anticonvulsants as well as referrals for serial neurodiagnostic tests.