Psychogenic non-epileptic seizures, also known as non-epileptic attack disorders,
are events superficially resembling an epileptic seizure, but without the
characteristic electrical discharges associated with epilepsy.
There is no scientific consensus as to what causes PNES. However, many
physicians believe the condition may be triggered by psychological problems. It
is estimated that 20% of seizure patients seen at specialist epilepsy
clinics have PNES. Diagnosis
The differential diagnosis of PNES firstly involves ruling out epilepsy as
the cause of the seizure episodes, along with other organic causes of
non-epileptic seizures, such as syncope, migraine, vertigo, and stroke, for
example. However, between 5-20% of patients with PNES also have epilepsy.
Frontal lobe seizures can be mistaken for PNES, though these tend to have
shorter duration, stereotyped patterns of movements and occurrence during
sleep. Next, factitious disorder and malingering are excluded. Finally other
psychiatric conditions that may superficially resemble seizures are
eliminated, including panic disorder, schizophrenia, and depersonalisation
disorder. The most conclusive test to distinguish
epilepsy from PNES is long term video-EEG monitoring, with the aim of
capturing one or two episodes on both videotape and EEG simultaneously.
Conventional EEG may not be particularly helpful because of a high false-positive
rate for abnormal findings in the general population, but also of abnormal
findings in patients with some of the psychiatric disorders that can mimic
PNES. Additional diagnostic criteria are usually considered when diagnosing PNES
from long term video-EEG monitoring because frontal lobe epilepsy may be
undetectable with surface EEGs. Following most tonic-clonic or complex
partial epileptic seizures, blood levels of serum prolactin rise, which can be
detected by laboratory testing if a sample is taken in the right time
window. However, due to false positives and variability in results this test is
relied upon less frequently. = Terminology =
The use of older terms including pseudoseizures and hysterical seizures
are discouraged. While it is correct that a non-epileptic seizure may
resemble an epileptic seizure, pseudo can also connote "false, fraudulent, or
pretending to be something that it is not." Non-epileptic seizures are not
false, fraudulent, or produced under any sort of pretense.
The condition may also be referred to as non-epileptic attack disorder,
functional seizures, or psychogenic non-epileptic seizures. Within DSM IV
the attacks are classified as a somatoform disorder, whilst in ICD 10
the term dissociative convulsions, is used, classed as a conversion disorder.
= Distinguishing features = Some features are more or less likely to
suggest PNES but they are not conclusive and should be considered within the
broader clinical picture. Features that are common in PNES but rarer in epilepsy
include: biting the tip of the tongue, seizures lasting more than 2 minutes,
seizures having a gradual onset, a fluctuating course of disease severity,
the eyes being closed during a seizure, and side to side head movements.
Features that are uncommon in PNES include automatisms, severe tongue
biting, biting the inside of the mouth, and incontinence.
If a patient with suspected PNES has an episode during a clinical examination,
there are a number of signs that can be elicited to help support or refute the
diagnosis of PNES. Compared to patients with epilepsy, patients with PNES will
tend to resist having their eyes forced open, will stop their hands from hitting
their own face if the hand is dropped over the head, and will fixate their
eyes in a way suggesting an absence of neurological interference. Mellers et
al. warn that such tests are neither conclusive nor impossible for a
determined patient with factitious disorder to "pass" through faking
convincingly. Risk factors
Most PNES patients are women, with onset in the late teens to early twenties
being typical. According to a study in 23 patients,
there is an elevated frequency of childhood abuse, especially in those
with motor involvement. Such findings have led to the proposal that PNES may
be an expression of repressed psychological harm in response to trauma
such as child abuse. However, the childhood abuse theory is by no means
universally accepted, and several studies controlling for other
demographic factors have failed to find a higher incidence of reported childhood
abuse in PNES patients than in a comparable patient groups with organic
disease. A number of studies have also reported a
high incidence of abnormal personality traits or personality disorders in
patients with PNES such as borderline personality. However, again, when an
appropriate control group is used, the incidence of such characteristics it not
always higher in PNES than in similar illnesses arising due to organic
disease. Treatment
There are a number of recommended steps to explain to people their diagnosis in
a sensitive and open manner. A negative diagnosis experience may cause
frustration and could cause a person to reject any further attempts at
treatment. Ten points to breaking the diagnosis to the person and their
caregivers are: Reasons for concluding they do not have
epilepsy What they do have
Emphasise they are not suspected of "putting on" the attacks
They are not "mad" Triggering "stresses" may not be
immediately apparent. Relevance of aetiological factors in
their case Maintaining factors
May improve after correct diagnosis Caution that anticonvulsant drug
withdrawal should be gradual Describe psychological treatment
Psychotherapy is the most frequently used treatment, which might include
cognitive behavioral therapy, insight-orientated therapy, and/or group
work. There is some tentative evidence supporting selective serotonin reuptake
inhibitor antidepressants. Prognosis
Though there is limited evidence, outcomes appear to be relatively poor
with a review of outcome studies finding that two thirds of PNES patients
continue to experience episodes and more than half are dependent on social
security at three-year followup. This outcome data was obtained in a
referral-based academic epilepsy center and loss to follow-up was considerable;
the authors point out ways in which this may have biased their outcome data.
Outcome was shown to be better in patients with higher IQ, social status,
greater educational attainments, younger age of onset and diagnosis, attacks with
less dramatic features, and fewer additional somatoform complaints.
History Hystero-epilepsy is a historical term
that refers to a condition described by 19th-century French neurologist
Jean-Martin Charcot where patients with neuroses "acquired" symptoms resembling
seizures as a result of being treated on the same ward as patients who genuinely
had epilepsy. References
External links Epilepsy Foundation article about
non-epileptic seizures Epilepsy.com article about non-epileptic
seizures National Society for Epilepsy article on
Non-epileptic attack disorder – a technical article aimed at health
professionals