Pseudoseizures: Evaluation and Treatment

Dr. Griffith

Disclosures

Medscape Psychiatry & Mental Health eJournal. 1997;2(2) 

In This Article

Diagnosis

Desai and colleagues[17] suggested 4 criteria for distinguishing pseudoseizures from neurologic seizures:

  1. During the paroxysmal behavior, the EEG is normal when it represents a pseudoseizure.

  2. Immediately following the paroxysmal behavior, the EEG shows no postictal slowing with pseudoseizures.

  3. The frequency of occurrence of pseudoseizures does not diminish with anticonvulsant treatment.

  4. The forms of paroxysmal behaviors seen during a pseudoseizure are inconsistent with the forms of behavior seen during neurologic seizures.

Pseudoseizures frequently present stereotyped motor phenomena, such as jerking and shaking, but in patterns that differ from those seen with neurologic seizures. Goal-directed behaviors, expressions of anger or violence, or uncoordinated flailing movements of the extremities are likely signs of pseudoseizures. Babinski signs are absent, and usually there is no pupillary dilatation during a pseudoseizure. Physical injury and tongue biting usually do not occur with pseudoseizures. Other clinical distinctions between epileptic seizures and pseudoseizures have been reviewed elsewhere and are summarized in Table I.

[7,18]

Such clinical criteria are most valid when a patient meets all the criteria. This, however, is often not the case in clinical practice. Of patients with complex-partial seizures, 20% to 30% have a limbic seizure focus that does not produce either ictal or interictal scalp EEG abnormalities due to attenuation of the signal through brain tissue, skull, and scalp.[19] Patients with panic attacks misdiagnosed as seizures can show paroxysmal EEG changes during the panic attack.[20] A minority of epileptic patients fail to achieve seizure control despite adequate trials on multiple anticonvulsants.[21] And some patients with seizures originating in limbic or prefrontal cortex show complex behaviors that appear to clinically represent nonepileptic pseudoseizures.[22]

Reliance on clinical examinations and routine EEG studies has been termed a Level I investigation by Ramani.[5] Level I investigations are sufficiently conclusive for a diagnosis in many cases. When findings are ambiguous, however, more intensive investigations may be required. Level II investigation involves EEG activation studies or ambulatory EEG monitoring. Level III investigation includes inpatient video/EEG studies, EEG telemetry, and direct observation of paroxysmal behaviors. For rare patients, investigation with nasopharyngeal or sphenoidal EEG leads, neurosurgically placed subdural electrode grids, or depth electrodes inserted into the brain parenchyma may be required as alternatives to use of the scalp EEG.[23]

For Level II investigations, efforts are made to provoke a seizure in the EEG laboratory. Hypnosis,[24] suggestion,[25,26] reenactment of a triggering situation,[27] and psychological stress interviews[25] have been used to activate pseudoseizures during EEG monitoring. These techniques have not been compared for efficacy in a systematic study.[7] The efficacy of each technique likely varies from one patient to another according to personality and other clinical characteristics.

When EEG activation fails to clarify the diagnosis, a patient can be fitted with an ambulatory EEG recording device that is worn as he or she conducts daily life activities. The patient either records seizure occurrences in a detailed diary or triggers an event marker on the EEG record. Seizure occurrences are then correlated with the presence or absence of paroxysmal changes on the EEG. The utility of ambulatory monitoring is sometimes limited by the ability of the patient and family to collaborate in the investigation. Ambulatory monitoring requires that the patient (often a child) tolerate limitations on mobility from the equipment and the discomfort of EEG leads. Responsible family members must accurately record occurrences of seizures and monitor care of the EEG recording system.

Level III investigations are necessary for diagnosis in 50% or fewer pseudoseizure cases. A patient is admitted to a hospital unit where behavioral observation by trained staff, serum anticonvulsant monitoring, simultaneous videotape/EEG recording, and telemetry can be conducted over several days. Either the observed form of seizure behavior or the absence of correlation between paroxysmal behavior and EEG changes can be used to establish a pseudoseizure diagnosis.

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