PNES has been described extensively in adults. There remains a relative paucity of literature in the pediatric age. There has been recent progress in understanding the etiology of PNES and in defining appropriate treatments. Unfortunately, most of these studies have been done in adults with PNES

Few studies have assessed the semiology of PNES exclusively in children and even fewer more recent studies have reported differences in the clinical features of PNES between younger children and adolescents, with respect to the semiology of the episodes and types of stressors [1,2]. Studies pertaining to PNES in children reported over the past 15 years have been listed in Web Table I.

In this review, we will discuss the clinical manifestations, predisposing factors, and appropriate workup for children and adolescents with possible PNES. We will review the recent literature on semiology, etiology, and treatment, particularly pertaining to children and adolescents.

Psychogenic nonepileptic seizures (PNES) are defined as paroxysmal events of altered movement or behavior that resemble epileptic seizures but are not due to cerebral neuronal dysfunction and are not associated with epileptiform abnormalities on the electroencephalogram (EEG) [3]. They are related to an underlying psychogenic process, thus differing from other paroxysmal nonepileptic events that are physiologic in origin.

A variety of terms have been used in the literature to describe PNES. Previously used terms such as hysteroepilepsy, pseudoseizures and pseudoepileptic or nonphysiologic seizures are considered pejorative or inappropriate, and have been replaced by more contemporary terms such as nonepileptic attacks, nonepileptic attack disorder and psychogenic nonepil-eptic seizures (PNES).

In the DSM-5 [4], they are listed in the somatic symptoms disorder section as conversion disorder or functional neurological symptom disorder with attacks. The term dissociative convulsions is used in the ICD 10 [5]. The term PNES, is non-judgmental, and is recommended as the preferred term to be used [6].

PNES are common and seen in all age groups. The prevalence of PNES in the general population is estimated to be 2-33/100,000 [7]. They represent 5-20% of outpatient adult epilepsy clinics and 10%-20% of referrals to adult epilepsy centers [7]. However, reported estimates of the incidence or prevalence of PNES may represent an underestimation, as these reports include only cases for which the diagnosis was confirmed by video-electroencephalography (VEEG) [8].

There are no studies of prevalence or incidence of PNES in children. 3.5-20% of children undergoing VEEG monitoring [1,2,9] have PNES and it has been reported in 11-38% of children with all types of paroxysmal non-epileptic events [10,11].

PNES are seen in all age groups. The average age at diagnosis of PNES in children in India was 8 years [12] to 12 years [13], and the average delay in diagnosis was 5 months [14] to 3 years [13]. Overall, there is no significant difference in the demographics of age of onset and delay in diagnosis in the reports from India versus those from the Western world.

PNES are more common in adolescents than in children [15,16]. There is a female preponderance more apparent in adults and adolescents than in children [12,13,17]. Many of these children are given a diagnosis of epilepsy and are mistakenly placed on anti-seizure medications.

A definitive diagnosis of PNES can be secured if the patient satisfies the ‘rule of 2s’ consisting of the following three criteria, which yields a positive predictive value of 85% [18,19]:

Accurate and prompt diagnosis of PNES can be a challenging task, especially since a proportion of these patients also have epilepsy. A detailed history is critical and important part of the evaluation. The interview should be customized accordingly.

PNES share some unique common features. These include frequent attacks that have not responded to appropriate medication, specific triggers (e.g. presence of stressors), occurrence of events only when spectators are present and recurrence in a particular setting. A detailed description of the episode by an eye witness or the patient should be obtained. The ready availability of smart phones and other digital recording devices allow for easy acquisition of video recordings as a useful tool in early diagnosis. Observation of the episode at bedside, or in the clinic by the physician aids in differentiating PNES from epileptic seizures and other paroxysmal non-epileptic events.

History of provoking factors, triggers or stressors of the events and associated psychiatric, neurologic and medical disorders should be obtained. There may also be presence of varied symptoms suggesting somatization.

A variety of risk factors have been identified as the etiologic basis of PNES. The most common risk factors in the pediatric age group are school related problems, seen in 21-46% of cases [1,14], reported more frequently in the adolescent age group [1,20] and exposure of the child to family dysfunction including parental divorce, sibling hostility and financial stress seen in 42-48% cases [1,14]. Interpersonal conflicts with teachers, peers and friends [1,20] are also seen frequently.

Physical and sexual abuse is reported less frequently in children, ranging from 0-32%, in contrast to a much higher frequency in adults [1,14,16,20,21]. Bereavement has been reported more frequently in adolescents [1]. One study reported a higher rate of suicidal attempts (13.5%) [16]. Self-related problems such as low self-esteem, body image issues and dependency, have also been reported [1,14].

Psychiatric comorbidity is common in children, adolescents, and adults with PNES. In patients of all age groups with PNES, emotional problems have been reported with varying frequency, from 13.8% to 84% [1,12,14-16,22]. The range may be due to differences in assessment for psychiatric comorbidity. Only a limited number of studies used structured interviews or standard measures.

Depression and anxiety are most common associated psychiatric disorders.in adults with PNES. There is controversy regarding the prevalence of these psychopathologies in children with PNES. In children, major depression ranges from 2.5% [14] to 45% [1,16,22-24]. It is more common in the adolescent age group [1]. Anxiety disorders have also been reported with varying frequencies from 16% [13] to 83% [24]. Bipolar and dysthymic disorder [21], adjustment disorder (8.8%) [14], panic disorder (2.5%) [14], post-traumatic stress disorder [24], separation anxiety and disruptive behavioral problems such as temper tantrums and aggressive behavior have also been reported [1]. Overall, it appears that, in Indian literature, the reported percentages for psychiatric disorders in children with PNES are lower [12-14]. This may be related to cultural differences, variability in referral patterns and limitations related to easy accessibility of psychiatric evaluations in children.

Concurrent epilepsy is seen commonly, occurring with varying frequency from 15-90 % [1,13,15,16] with higher rates noted in children younger than 12 years [1]. Family history of epilepsy is a common finding seen in 25%-43% of patients [1,15]. It is thought that observation of a seizure in a family member may serve as a behavioral model for the child to shape expression of their own conversion symptoms. Frequently, these patients are mistakenly started on anti-seizure medications, and a large percentage ranging from 35-79% were reported to be unnecessarily treated. [1,13,14,25].

Pseudo-status epilepticus may occur and was reported in one study in 13.5% children with PNES [1]. This is a serious problem as it can be associated with iatrogenic complications and considerable distress to the child and family.

Coexisting neurologic illness has been reported in almost half of the children (55%), most frequently cognitive dysfunction (39%) which was significantly more common in the younger children (P<0.0001). Less frequent associated conditions include attention deficit hyperactivity disorder (20.3%), headaches (19%) and past head trauma (10%) [1].

Medical comorbidities have been reported in 7.5% of patients [14]. Children with PNES have more associated medical illnesses than their siblings and have been noted to be on more prescribed as well as over the counter medications than their siblings, suggesting that chronic illness may also act as a stressor for inducing PNES. These children are also exposed to more lifetime adversities such as bullying and domestic or community violence. Parents of children with PNES reported more somatization as compared to parents of children with epilepsy suggesting that this becomes an intergenerational family communication model [20].

From the preceding two sections, one can see that PNES is a heterogeneous disorder with no uniform predisposing factors or comorbidity. Pathways exist for development of PNES. Some children may have significant pre-existing stressors whereas others may have no apparent etiology for PNES. Each child with PNES must be evaluated individually. Nevertheless, there is new information that helps improve understanding PNES. Reuber and Brown, et al. [26] proposed an integrated cognitive model. The motor manifestations of PNES are seen as an instinctual freeze or flight response or a learned motor pattern from experiencing or witnessing a seizure or seizure-like episode. These motor manifestations are triggered by threat or distress. The seizure-like episodes allow escape from the psychological distress and cause parasympathetic activation reducing stress. The seizure-like episodes thus become reinforcing. This neuropsychological model is supported by recent neuroimaging data that have shown changes in the limbic system and in the right inferior frontal cortex, a region involved in motor inhibition [27].

Differentiating PNES from epileptic seizures is the first and important step of the evaluation. Some of the major differences between the clinical features of nonepileptic and epileptic seizures has been summarized in Table I. PNES last longer than epileptic seizures in both adults and children [2,8]. Side to side head movements and disorganized, asynchronous, out-of-phase extremity movements suggest PNES. They have a gradual onset and termination, with preservation of consciousness during and immediately after events, even with generalized motor activity. Associated injury, tongue bite (usually involving the tip of the tongue) and urinary incontinence are infrequent. Negative emotions such as weeping, crying, or fear [2,13,14], may occur during and after the event, unlike the monotonous cry heard at the onset of some epileptic seizures. However, negative emotional signs have also been seen with epileptic seizures [28], and therefore does not categorically help with differentiating the two. The PNES episodes are often stereotypic, reported in up to 73% of the cases, suggesting that stereotypic nature of the episodes does not necessarily always suggest epilepsy [1,13,29].