Neuropsychiatric Symptoms of Epilepsy

9 Dissociation
147
Table 9.1 Non-epileptic differential diagnosis of dissociative seizures [ 45 ]
Somatogenic non-epileptic paroxysms
Syncope
Toxic or drug-induced events
Transient ischemic attack
Migraine attack
Vertigo attack
Sleep-associated disorders, e.g., narcolepsy, parasomnias
Movement disorders, e.g., choreoathethosis
Hyperekplexia
Hypoglycemic events
Psychogenic non-epileptic
paroxysms
Panic attack
Dissociative fugue
Dissociative stupor
Psychogenic hyperventilation
Psychotic catatonia
Psychotic stupor
Artificial paroxysmal events
Simulation of paroxysmal events
Reprinted with kind permission from Springer Science + Business Media and Springer Medizin
Verlag Heidelberg, Germany from Schmutz et al. [ 45 ], © 2009
The combined video-EEG recording of a typical seizure remains the gold standard
to confirm the diagnosis [ 36 ]. Ictal EEG findings with no activity typical for epilepsy in
combination with semiological features suggestive for dissociative seizures do provide
a high diagnostic certainty. However, home-based long-term EEG registration or Video-
EEG registration in telemetry unit are expensive examinations usually reserved to tertiary
centers. In many cases, the diagnosis has to be based on a normal standard EEG,
the reported seizure history, and the reported semiological characteristics. However, no
single semiological sign featuring a clear and unambiguous pathognomonic significance
has been identified so far. The “ arc de cercle ,” the posture of opisthotonus with a
reclination of the head and an overextension of the trunk, used to be one of the prevalent
seizure signs of the female hysterics in the era of Charcot and Freud. Occasionally, it
can be observed in both men and women still today. It is a semiological feature, which
is certainly unusual in epilepsy and rather indicative for dissociative seizures.
Some seizure signs (see Table 9.2 ) are diagnostically suggestive. Together with
the anamnestic data and the EEG-findings they may facilitate a comprehensive clinical
judgment.
There are some studies indicating that psychometric findings pertaining to personality
features might differentiate between patients with dissociative seizures and
patients with epileptic seizures [ 47 , 48 ]. The limited accuracy, though, does not
allow a reliable diagnostic classification, and the results remain indicative.
A micro-linguistic approach focusing on patient’s spontaneous seizure narratives
proves to reveal most interesting results, from both a differential diagnostic and a
psychological point of view [ 49 ]. Patients with epileptic seizures use complex and
repeating pattern of phrasing to describe their seizures; furthermore, they frequently
mention attempts to stop their seizures by specific countermeasures. In contrast,
dissociative patients basically omit their seizures in their spontaneous seizure narrative,
thereby using simple and stereotype patterns of phrasing. Some promising
empirical validation studies show that the method features quite powerful differential
diagnostic properties [ 50 ]. A broader clinical application, however, will be limited
by complexity and costs.