Psychogenic non-epileptic seizures
|Psychogenic non-epileptic seizures|
|Classification and external resources|
Psychogenic non-epileptic seizures (PNES), also known as non-epileptic attack disorders (NEAD), are events superficially resembling an epileptic seizure, but without the characteristic electrical discharges associated with epilepsy.
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 (simulating seizures intentionally for psychological reasons) and malingering (simulating seizures intentionally for secondary gain such as compensation or avoidance of criminal punishment) 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 (some clinicians may use suggestion to attempt to trigger an episode). 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.
According to a study in 23 patients, there is an elevated frequency of childhood abuse, especially in those with motor involvement. A study has indicated that the metaphors patients use are associated with repressed memories.
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.
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.
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 (easiest factor to distinguish), 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 (automatic complex movements during the seizure), 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 (if they are closed during the seizure), 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.
Most PNES patients (75%) are women, with onset in the late teens to early twenties being typical. PNES patients often have a history of multiple vague, unexplained medical problems and may have a psychiatric condition such as major depressive disorder or an anxiety disorder or bipolar disorder. A number of researchers have identified abnormal personality traits or personality disorders in patients with PNES such as borderline personality. The presence of these personality disorders, often related to a trauma in childhood, has led to researchers postulating that PNES may be an expression of repressed psychological harm in response to trauma such as child abuse. Over-emphasising these theories to patients may lead to false memory syndrome so they should be introduced delicately. Other traumatic experiences such as bullying in adulthood, learning disabilities, sexual abuse or adverse family dynamics may also be important pre-disposing or maintaining factors.
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 (describe dissociation)
- 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 the selective serotonin reuptake inhibitor antidepressants.
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.
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.
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- Epilepsy Foundation article about non-epileptic seizures
- Epilepsy.com article about non-epileptic seizures
- National Society for Epilepsy (UK) article on Non-epileptic attack disorder – a technical article aimed at health professionals