Biomedical subjects

Michelangelo Stanzani-Maserati

Publications and source records attributed to Michelangelo Stanzani-Maserati.

3 recordsLinked to original sources

PubMed2005

Negative myoclonus induced by cortical electrical stimulation in epileptic patients.

Negative myoclonus (NM) is a motor disorder characterized by a sudden and abrupt interruption of muscular activity. The EMG correlate of NM is a brief (<500 ms) silent period (SP) not preceded by any enhancement of EMG activity (i.e. myoclonus). This study investigated the role of premotor cortex (PMC), primary motor cortex (MI), primary somatosensory area (SI) and supplementary motor area (SMA) in the pathophysiology of cortical NM by means of intracerebral low frequency (1 Hz) electrical stimulation. In three drug-resistant epileptic patients undergoing presurgical evaluation, we delivered single electric pulses (stimulus duration: 3 ms; stimulus intensity ranging from 0.4 to 3 mA) to PMC (2 patients), MI (1 patient), SI and SMA through stereo-EEG electrodes; surface EMG was collected from both deltoids. The results showed that (i) the stimulation of PMC or MI could evoke a motor evoked potential (MEP) either at rest or during contraction, in this latter case followed by an SP; however, in two patients, at the lowest stimulus intensities (0.4 mA), 50% of stimuli could induce a pure SP, i.e. not preceded by an MEP; raising the intensity of stimulation (0.6 mA), the SPs showed an antecedent MEP in >80% of stimuli; (ii) the stimulation of SI at low stimulus intensities (from 0.4 to 0.8 mA) induced in two patients only SPs, never associated with an antecedent MEP, whereas in the third subject the SPs could be inconstantly preceded by an MEP; by incrementing the stimulus intensity (up to 3 mA), in all three patients the SPs tended to be preceded, although not constantly, by an MEP; stimulus intensity affected SP duration (i.e. the higher the intensity, the longer the SP), without influencing the latency of onset of the SPs; (iii) the stimulation of SMA induced only pure SPs, at all stimulus intensities up to 3 mA; as for SI, increment of stimulus intensity was paralleled by an increase in SP duration, without influencing the onset latency of SPs. We conclude that single electric pulse stimulation of PMC, MI, SI and SMA through stereo-EEG electrodes can induce pure SPs, not preceded by an MEP, which clinically appear as NM, suggesting therefore that these cortical areas may be involved in the genesis of this motor phenomenon. However, it must be pointed out that SMA stimulation induced only pure SPs, regardless of the stimulus intensity, whereas occurrence of pure SPs following stimulation of PMC, MI, and SI depended mainly on the intensity of stimulation.

Adolescent↗

PubMed2005

Biting behavior, aggression, and seizures.

PURPOSE: 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.

Adult↗

PubMed2003

The expression of interictal, preictal, and postictal facial-wiping behavior in temporal lobe epilepsy: a neuro-ethological analysis and interpretation.

By videotape recordings analysis we investigated the frequencies of interictal, preictal, and postictal wiping or rubbing movements targeting the face region (face wiping, FW) in 17 right and 13 left mesial temporal lobe epilepsy (MTLE) patients. Patients' data were compared with FW frequencies obtained in 22 healthy controls listening to a presentation. Results showed that: (1) FW movements were present in both controls and patients; however, the patient groups showed lower interictal and preictal FW rates relative than controls; (2) right and left temporal lobe seizures were followed by a marked increase in the expression of wiping activities directed to the nose as well as to other face regions with respect to the interictal-preictal period; (3) during the first 5min postictal FW was performed preferentially with the hand ipsilateral to the seizure focus; (4) postictal examination of the patient by an observer, especially if of the opposite sex, resulted in a higher incidence of FW acts. After temporal lobe seizures there is an exaggerated expression of movements targeting the face region, and not exclusively directed to the nose. According to an ethological interpretation of the FW behavior as a motor behavior present throughout the phylogenetic scale, from rodents to primates, we suggest the postictal emergence of an innate action pattern modulated by external emotional-cognitive stimuli.

Adolescent↗