Epileptic Hallucinations and Illusions

Visual hallucinations

M.R. Sperling, Thomas Jefferson University, Philadelphia, PA, USA

Seizures can produce both formed and unformed visual hallucina-tions. Primary involvement of striate and some extrastriate corticestypically leads to unformed, flashing lights, whereas occipital orposterior temporal association cortex involvement at the start ofseizures can lead to formed visual hallucinations, e.g., people,manmade or natural objects. In addition, other cortical regions,including dominant and non-dominant frontal lobes, may alsoproduce these symptoms. Epileptic visual hallucinations must bedistinguished from non-epileptic phenomena, as may be seen inCharles Bonnet syndrome, for example. The pathophysiology offormed hallucinations is poorly understood, perhaps caused by loss ofinhibition of normal suppressive mechanisms and activation of storedvisual memories. The hallucinations sometimes have a strongaffective component, suggesting intimate involvement of limbicstructures in some cases.

doi:10.1016/j.yebeh.2012.04.059

Olfactory hallucinations

F. Andermann, Montreal Neurology Hospital and Institute, McGillUniversity, Canada

Phantosmia or smelling without an object being there may be dueto several causes. It is relatively rare in temporal lobe epilepsy.Distinction from an abnormal and unexplained taste may be difficultin patients with temporal lobe epilepsy. The literature contains morereports about unusual smells associated with migraine than withepilepsy. Local causes and psychiatric conditions must also beconsidered in the differential diagnosis.

doi:10.1016/j.yebeh.2012.04.060

Epileptic and nonepileptic hallucinations: A new look at thedifferential diagnosis

F. Andermann, McGill University, Canada, Montreal Neurology Hospitaland Institute, Canada

Complexepileptic visual, auditory and emotional hallucinations areof course well recognized, but their differential diagnosis fromnonepileptic events continues to present a practical problem. Complexexperiential hallucinations seem to be less common today than theywere earlier in patients studied with a view to surgical treatment.Perhaps a change in the indications for surgical treatment may beresponsible for a diminished emphasis on these clinical features.

The specific significance of the context and additional clinicalfeatures in addition to the actual hallucinations are often notrecognized by other medical specialists, particularly psychiatrists.

The role of sensory deprivation such as in the Charles BonnetSyndrome, symptoms of diencephalic lesions such as in peduncularhallucinosis and even illusions of familiarity or strangeness, whichmay also be of a nonepileptic nature will be discussed.

doi:10.1016/j.yebeh.2012.04.061

Unveiling the mystery of déjà vu

M. Brázdil, Brno Epilepsy Center, Department of Neurology, St. Anne'sUniversity Hospital and Medical Faculty of Masaryk University, Brno,Czech Republic

Déjà vu is an eerie experience that is characterized by therecognition of a situation concurrent with the awareness that thisrecognition is inappropriate. This feeling of irrelevant familiarity is acommon phenomenon occurring both in clinical (mainly epileptic)and nonclinical population. Despite numerous theories that havebeen suggested as to what nonpathological déjà vu is and whatcauses it, until now no ultimate explanation has been generallyaccepted.

We investigated differences in brain morphology between healthysubjects with and without déjà vu using a novel multivariateneuroimaging technique, source-based morphometry.

The analysis revealed a set of cortical (predominantly mesiotem-poral) and subcortical regions in which there was significantly lessgray matter in subjects reporting déjà vu. In these regions gray mattervolume was inversely correlated with the frequency of déjà vu.

Our results demonstrate for the first time a structural correlate ofdéjà vu in healthy individuals and implicate a direct pathogenetic linkbetween nonpathological and epileptic déjà vu. We hypothesize thatour findings reflect an alteration of hippocampal function andpostnatal neurogenesis in subjects with déjà vu.

doi:10.1016/j.yebeh.2012.04.062

Pre-ictal, Peri-ictal/Ictal Neuropsychiatric Manifestation

Pre-ictal psychiatric symptoms

M. Mula, Department of Clinical & Experimental Medicine, AmedeoAvogadro University, Division of Neurology, University Hospital Maggioredella Carità, Novara, Italy

Pre-ictal psychiatric symptoms usually consist of cluster ofsymptoms preceding seizures of variable duration, ranging from afew minutes up to three days. Such symptoms, although notcharacterized by any detectable surface EEG change, probablyrepresent the expression of underlying epileptic activity. Aroundone third of patients with partial seizures report premonitorysymptoms, usually before secondary generalized tonic-clonic sei-zures. Prodromal moods of depression or irritability may occurhours to days before a seizure and are often relieved by theconvulsion. Different authors pointed out that behavioral changesare the most frequently reported pre-ictal symptoms, beingcharacterized by irritability or decreased tolerance and lastingseveral hours. These symptoms usually worsen in severity closerto the time of the seizure and remit approximately 1 day after theseizure, although in some cases symptoms may persist for up to3 days after the seizure. Recently, a prevalence of pre-ictal dysphoricsymptoms in patients with epilepsy has been reported. Around 13%of patients experienced irritability, dysphoria or depressed moodpreceding seizures. Such feelings are almost indistinguishable frominter-ictal ones, apart from duration and close relation with seizureoccurrence. It seems, therefore, important for clinicians to inquireabout these phenomena, because they cannot be detected by ratingscales or questionnaires.

doi:10.1016/j.yebeh.2012.04.063

Abstracts318