1. Context
2. Evidence Acquisition
2.1. Overview
2.2. Literature Search
2.2.1. Databases Searched
2.2.2. Search Strategy
2.2.3. Time Frame and Language
2.3. Inclusion and Exclusion Criteria
2.3.1. Inclusion Criteria
2.3.2. Exclusion Criteria
2.4. Data Extraction and Analysis
2.4.1. Data Collection Process
2.4.2. Data Synthesis
2.5. Quality Assessment
2.5.1. Evaluation of Studies
2.5.2. Bias Assessment
3. Results
3.1. Search Results and Study Selection
3.1.1 Studies Characteristics and Main Findings
| Study Author and Year | Study Design | Population Characteristics | Diagnostic Criteria for NES |
|---|---|---|---|
| An et al., 2010 (10) | Retrospective review | 64 patients with PNES diagnosis | PNES diagnosed via video/EEG monitoring |
| LaFrance et al., 2013 (16) | Cross-sectional study | 255 patients with EEG-confirmed PNES | PNES confirmed by video EEG |
| Mokleby et al., 2002 (17) | Comparative, cross-sectional study | 23 PNES patients, 23 SD patients, 23 healthy controls | PNES diagnosed based on clinical and EEG criteria |
| Barry et al., 2005 (18) | Retrospective review | 157 patients with NES at a medical center | NES confirmed by video EEG |
| Westbrook et al., 2005 (19) | Retrospective record review | 102 inpatients with NES | NES diagnosed via video EEG and psychiatric interview |
| Pakalnis and Paolicchi, 2000 (20) | Prospective study | 148 pediatric patients with probable seizure disorder | Psychogenic seizures identified by video EEG |
| Salinsky et al., 2015 (21) | Retrospective review | Veterans with PNES or ES diagnosis | PNES and ES diagnosed during epilepsy monitoring |
Abbreviations: PNES, psychogenic nonepileptic seizures; ES, epileptic seizures.
| Study Author and Year | Key Findings | Prevalence of mTBI in NES Patients |
|---|---|---|
| An et al., 2010 (10) | 20.3% with head injuries, mostly mild; psychological trauma noted | 20.3% (mostly mild) |
| LaFrance et al., 2013 (16) | 44.6% with TBI, majority mTBI; higher psychiatric comorbidity in TBI group | 44.6% (majority mTBI) |
| Mokleby et al., 2002 (17) | 83% reported minor head traumas; higher levels of psychiatric comorbidity | 83% (minor head traumas) |
| Barry et al., 2005 (18) | 24% with nonepileptic PTS, 78% involving mild HIS; psychiatric problems common | 24% (78% mild HIS) |
| Westbrook et al., 2005 (19) | 32% with head injury, majority minor; high prevalence of psychiatric disorders | 32% (majority minor) |
| Pakalnis and Paolicchi, 2000 (20) | 44% with head injury, more than half mild; focus on pediatric patients | 44% (more than half mild) |
| Salinsky et al., 2015 (21) | 57% with TBI as seizure etiology, 87% mild TBI; significant role of PTSD | 57% (87% mild TBI) |
Abbreviations: mTBI, mild traumatic brain injury; PTS, post-traumatic seizures; PTSD, post-traumatic stress disorder.
3.1.2. Summary
3.2. Comorbidities in Mild Traumatic Brain Injury and Psychogenic Nonepileptic Seizures
3.3. Psychiatric Comorbidities
3.3.1. Mood Disorders and Depression
3.3.2. Post-traumatic Stress Disorder
3.4. History of Trauma and Abuse
3.5. Other Comorbidities
3.5.1. Behavioral Impulsivity and Hostility
3.5.2. Neurological Comorbidities
3.6. Quality Assessment of the Studies
3.6.1. General Approach
3.6.2. Assessment of Individual Studies
| Study | Selection Bias | Performance Bias | Detection Bias | Attrition Bias | Reporting Bias | Publication Bias | Confounding Bias | Other Bias | Internal Validity | External Validity |
|---|---|---|---|---|---|---|---|---|---|---|
| LaFrance et al., 2013 (16) | Low | Moderate | Low | Low | Low | Moderate | Moderate | Low | High | Moderate |
| An et al., 2010 (10) | Moderate | Moderate | Low | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| Mokleby et al., 2002 (17) | Moderate | Low | Moderate | Low | Moderate | Moderate | High | Low | Moderate | Low |
| Barry et al., 2005 (18) | Moderate | High | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Low |
| Westbrook et al., 2005 (19) | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | High | Moderate | Moderate | Moderate |
| Pakalnis and Paolicchi, 2000 (20) | Low | Moderate | Low | Low | Low | Moderate | Moderate | Low | High | High |
| Salinsky et al., 2015 (21) | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | High | Moderate | - | Moderate |
Risk of bias summary: This bar chart represents a summary of the risk of bias assessment across 10 domains (D1-D10) which are detailed on Table 3 for the studies included in the systematic review.

