De oorzaak bleek een epilepsie-aanval te zijn thv. bepaalde delen van de hersenen (de linker basale ganglia met de capsula interna en verder nog de rechter insula):
A 62-year-old right-handed woman presented ... including a complex sensation characterized by feeling the presence of several members of her family in the immediate environment, associated with paresthesia of the right hemibody (excluding the face). The feeling of presences and the paresthesia (numbness) appeared concomitantly and lasted in total several minutes.
The episode occurred while she was sitting alone on the sofa of her living room and immediately felt the presence of four persons in her frontal space. She did not see or hear these persons (no visual or auditory hallucinations), but felt vividly their presence in her peripersonal [within reach] and near extrapersonal space [just outside of reach]. She “recognized” them as close family members. Closest was her grand-daughter who was sitting on the floor immediately in front of her, without any left or right lateralization in relation to her body, whereas the three other persons, her daughter and two other grand-children, were experienced to be localized at a distance of several meters. ... This highly vivid and convincing feeling of presences was described by the patient as deeply pleasant, although she guessed that it was not possible that they were really there, as she was alone just before. ...
De basale ganglia zijn hier blauw gekleurd.
MRIs revealed abnormal findings due to a right hemisphere subcortical stroke 10 months before the episode (Fig. 1A). The patient's stroke affected a portion of the basal ganglia (the putamen and the globus pallidus) and a large white matter tract within (the internal capsule).
Left hemisphere findings in the insular cortex were also apparent, and this was the likely seizure focus. Strokes are known to increase the incidence of seizures: in one study 8.6% of those with ischemic stroke [occlusion of blood supply] and 10.6% of those with hemorrhagic stroke [bleed] had one or more seizures within a year (Bladin et al., 2000).
Instead, the felt presence was more akin to a "hallucination" for known people going about normal daily activities. Nonetheless, involvement of the insula, important for interoceptive awareness of bodily states (Craig, 2009), is still suggestive of a disruption in the sense of self and its interaction with the external world.
Nadat ze behandeld was met een anti-epilepticum (Pregabaline = Lyrica®) had ze geen zo'n ervaringen meer.
uit: The Neurocritic: Paranormal Seizure Activity
She was treated with pregabalin (300 mg/day) and there was no recurrence of simple or complex partial seizures and no further feeling of presences.
abstract van het artikel: Picard, F. (febr. 2010). Epileptic feeling of multiple presences in the frontal space. Cortex
Deze casusbeschrijving zal waarschijnlijk niet alle fenomenen van die aard verklaren, maar ze biedt toch weer wat meer inzicht in hoe onze hersenen soms in staat zijn om bizarre ervaringen op te wekken (al gaat het hier natuurlijk om een dysfunctioneren van bepaalde hersendelen)...
Veranderd door Dido, 28 maart 2010 - 23:04