Biting behavior, aggression, and seizures.
OBJECTIVE
To describe the semiologic features of aggressive behaviors observed in human epileptic seizures with particular reference to the act of biting a conspecific.


METHODS
We analyzed the biting behavior (BB) and other aggressive gestures occurring in a group of 11 patients retrospectively selected from >1,000 patients subjected to video-EEG/SEEG monitoring for presurgical evaluation of drug-resistant seizures.


RESULTS
Patients displaying BB showed (a) a male sex predominance, (b) heterogeneous etiologies and lesion locations, and (c) seizures involving the frontotemporal regions of both hemispheres. The act of biting was a rapid motor action, lasting approximately 600 ms, occurring in the context of strong emotional arousal, fear, and anger, with various bodily gestures with aggressive connotation. BB was mainly a "reflexive" behavior, in that biting acts were evoked (both during and after seizures) by actions of people in close contact with the patient. The sole intrusion of the examiner's hand in the space near the patient's face was effective in triggering BB. Rarely, self-directed or object-directed biting acts were not triggered by external stimuli. Intracranial data (SEEG) obtained in one subject showed that the amygdala/hippocampal region plus the orbitomedial prefrontal cortex had to be involved by ictal activity to observe BB.


CONCLUSIONS
Anatomic and electrophysiologic data in our patients suggest that a model of dual--temporal and frontal--dysfunction could account for the occurrence of ictal/postictal BB. Behavioral data suggest also that BB and related aggressive gestures can be considered as the emergence of instinctive behaviors with an adaptative significance of defense of the peripersonal space.
Tassinari
Carlo Alberto
CA
Division of Neurology, Department of Neurosciences, Bellaria Hospital, University of Bologna, Italy.
Tassi
Laura
L
Calandra-Buonaura
Giovanna
G
Stanzani-Maserati
Michelangelo
M
Fini
Nicola
N
Pizza
Fabio
F
Sartori
Ivana
I
Michelucci
Roberto
R
Lo Russo
Giorgio
G
Meletti
Stefano
S
D000328:Adult; D000374:Aggression / Q000523:psychology*; D001734:Bites, Human / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D001921:Brain / Q000503:physiopathology; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods / Q000706:statistics & numerical data; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D005149:Facial Expression; D005260:Female; D007839:Functional Laterality; D005868:Gestures; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010550:Personal Space; D012737:Sex Factors; D013238:Stereotaxic Techniques; D014743:Videotape Recording; D014754:Violence / Q000523:psychology / Q000706:statistics & numerical data