Biomedical subjects
Publications and source records attributed to Fabio Placidi.
Psychiatric and neurological disturbances can show up with panic attack symptoms. This report illustrates the difficulty in distinguishing between panic disorder and epilepsy in a subgroup of epileptic patients that suffer panic attacks as symptoms of seizures. This is the first report of panic attacks due to a focal lesion involving the left temporal lobe and the second case of panic attacks related to a meningioma.
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We examined the effects of sleep microstructure, ie, the cyclic alternating pattern (CAP), on heart rate (HR)- and blood pressure (BP)-regulating mechanisms and on baroreflex control of HR in healthy humans and tested the hypothesis that sympathetic activation occurring in CAP epochs during non-rapid eye movement (non-REM) sleep periods is buffered by the arterial baroreflex. Ten healthy males underwent polysomnography and simultaneous recording of BP, ECG, and respiration. Baroreflex sensitivity (BRS) was calculated by the sequences method. Autoregressive power spectral analysis was used to investigate R-R interval (RRI) and BP variabilities. During overall non-REM sleep, BP decreased and RRI increased in comparison to wakefulness, with concomitant decreases in low-frequency RRI and BP oscillations and increases in high-frequency RRI oscillations. These changes were reversed during REM to wakefulness levels, with the exception of RRI. During CAP, BP increased significantly in comparison to non-CAP and did not differ from REM and wakefulness. The low-frequency component of BP variability was significantly higher during CAP than non-CAP. RRI and its low-frequency spectral component did not differ between CAP and non-CAP. BRS significantly increased during CAP in comparison to non-CAP. BRS was not different during CAP and REM and was greater during both in comparison with the awake state. Even during sleep stages, like non-REM sleep, characterized by an overall vagal predominance, phases of sustained sympathetic activation do occur that resemble that occurring during REM. Throughout the overnight sleep period, the arterial baroreflex acts to buffer surges of sympathetic activation by means of rapid changes in cardiac vagal circuits.
PURPOSE: To evaluate the effects of topiramate (TPM) on interictal epileptiform abnormalities (IEA) and background activity by means of a computerized EEG analysis, in adult patients affected by focal epilepsy, with or without secondarily generalization, treated with TPM as adjunctive therapy or monotherapy. METHODS: Twenty-four patients affected by symptomatic or cryptogenic focal epilepsy underwent long-term video-EEG recording before and after TPM addition (mean dose 175+/-25 mg per day). RESULTS: TPM addition induced a significant reduction of both partial and secondarily generalized tonic-clonic (SGTC) seizures; treatment responder patients (seizure reduction > or = 50%) were 19 out of 24 patients (79.1%), of whom 5 were seizure-free. Quantitative analysis of IEA showed a significant decrease in the mean number of spikes/10 min during TPM therapy ( 4.2+/-4.2 versus 2.2+/-4.4; P<0.003 ). The analysis of spatial distribution of interictal spikes showed that such reduction was more evident at the level of the epileptogenic area rather than on the spreading component. Statistical analysis revealed only a significant decrease of mean relative power of alpha band in the EEG spectral content, recorded at rest in a group of 18 out of 24 epileptic patients during TPM therapy. In addition, during TPM treatment we observed a significant reduction in alpha reactivity without any important changes of alpha indexes (peak frequency and median frequency). CONCLUSION: These findings suggest that TPM has a strong inhibitory effect on IEA, probably acting on the generating processes, and, if used at low dosage and gradually titrated, seems to have only mild interferences with EEG background activity.
OBJECTIVE: To investigate the relationship between the electroencephalographic (EEG) power spectra features obtained by quantitative EEG (qEEG) and the hemodynamic parameters detected by dynamic susceptibility contrast-enhanced MR imaging (DSC MRI) in patients with Alzheimer's disease (AD). METHODS: Fourteen patients with probable AD and 15 elderly healthy controls were included in the study. All subjects underwent both EEG recording in a rest condition and perfusion MRI. Three EEG scalp areas were defined (anterior, central and posterior) and power spectra values were obtained from each scalp area. Relative values of temporoparietal and sensorimotor regional cerebral blood volume (rCBV) were measured bilaterally and successively averaged to obtain a total perfusion index. The brain atrophy index was calculated and used as a covariate to rCBV. Correlation analysis was performed between EEG variables and hemodynamic-morphological parameters. RESULTS: qEEG power spectra of AD patients were characterized by an increase in mean relative power of theta (4-7.75 Hz) associated with a decrease in alpha (8-12.75 Hz) frequency bands with a topographic distribution over the central and posterior EEG scalp regions, when compared with controls; beta (13-31 Hz) frequency band also displayed a significant decrease over the anterior and posterior EEG scalp regions of AD patients with respect to controls. The DSC MRI revealed a bilateral reduction in the temporoparietal and sensorimotor rCBV with respect to controls. Correlation analysis showed that the total level of hypoperfusion selectively correlates with the EEG power spectra in theta and alpha frequency bands distributed over anterior/central and central region, respectively. Within AD patients, the lower the level of hypoperfusion, the higher the content of EEG power spectra in theta frequency band, and the lower the level of hypoperfusion, the lower the content of EEG power spectra in alpha band. CONCLUSIONS: The combined qEEG and DSC MRI technology unveiled a selective correlation between neurophysiological and hemodynamical patterns in AD patients. Further investigations will ascertain the relevance of this multi-modal approach in the heterogeneous clinical context of AD.
OBJECTIVE: We examined the effects of the various sleep stages on baroreflex sensitivity (BRS), and heart rate and blood pressure (BP) variability, and tested the hypothesis that there is a different behavior of the baroreflex control of the sinus node in response to hypertensive and hypotensive stimuli and in relation to different cycles of the overnight sleep. DESIGN: Polygraphic sleep recordings were performed in 10 healthy males. The BP and the RR interval were continuously recorded during sleep. METHODS: BRS was calculated by the sequences method. Autoregressive power spectral analysis was used to investigate the RR-interval and BP variabilities. RESULTS: During rapid eye movement (REM) sleep BRS significantly increased in response to hypertensive stimuli in comparison with non-rapid eye movement (NREM) sleep and the awake state, whereas it did not change in response to hypotensive stimuli. In the first sleep cycle, BRS significantly increased during NREM in comparison with wakefulness, whereas during REM BRS in response to hypertensive stimuli did not show significant changes as compared with the awake state and/or with NREM. During REM occurring in the sleep cycle before morning awakening, BRS showed a significant increase in response to hypertensive stimuli in comparison with both NREM and the awake state. CONCLUSIONS: During sleep, arterial baroreflex modulation of the sinus node is different in response to hypotensive and hypertensive stimuli particularly during REM. Furthermore, baroreflex control of the sinus node shows a non-uniform behavior during REM occurring in different nocturnal sleep cycles. These findings suggest that the arterial baroreflex is more effective in buffering the increased sympathetic activation associated with REM at the end of sleep than in the early night.
The aim of this study was to verify the symmetry of cerebral blood flow changes during the generalized spike-wave discharges of typical absence seizures. A recording of mean flow velocity in the left and right middle cerebral arteries and of electroencephalographic activity was performed simultaneously in two subjects with multiple daily absence seizures. A total of 12 generalized spike-wave discharges were recorded. Mean flow velocities showed a significant increase during the discharges with respect to baseline. The increase of flow velocity started simultaneously or a few seconds before the discharges. In 91.6 % of all recordings, the percentage increase of mean flow velocity was significantly higher in the left than in the right side (7.03 % +/- 3.3 vs 5.14 % +/- 3.3; p < 0.1). The extent of the following decrease of flow velocity was also significantly greater in the left than in the right side (-16.91 % +/- 8.1 vs -14.07 % +/- 8.3; p < 0.01). These findings show an inter-hemispheric asymmetry in cerebral blood flow during generalized spike-wave discharges in two patients with absence seizures. Transcranial Doppler ultrasonography promises to be an interesting approach to detect rapid changes in cerebral hemispheric activity not otherwise recognizable.
PURPOSE: To study the possible correlation between interictal EEG patterns and neuroradiologic data obtained by dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) in patients with partial epilepsy. METHODS: Seventeen subjects with cryptogenic partial epilepsy underwent long-term video-EEG monitoring and DSC-MRI in the same session. Ten patients had temporal lobe epilepsy (TLE) and seven, epilepsy of extratemporal origin (ExTE). MRI data were compared with EEG findings, and the accuracy of DSC-MRI was analyzed considering spiking rate (number of interictal epileptiform abnormalities, IEA/min) and type of epilepsy. RESULTS: DSC-MRI showed a relevant asymmetry in the frontal, temporal, and occipital regions in eight (47%) of 17 patients, consisting of a relative regional cerebral blood volume (rCBV) increase in these areas. Because this region corresponded to the interictal EEG focus (IEF) or to the hemisphere involved in the genesis of epileptic discharges in most patients showing a higher spiking rate, patients were classified in two groups: patients with high spiking rate (HSR, n = 9) and with low spiking rate (LSR, n = 8); the cutoff corresponded to the median value of IEA/min. The rCBV increase corresponded to the IEF or to the hemisphere involved in the genesis of epileptic discharges in seven (77.7%) of nine HSR patients. No patients with LSR showed significant asymmetries in rCBV pattern. In five of six patients with TLE-HSR (83.3%), DSC-MRI showed a relative rCBV increase concordant with IEF or hemisphere involved in the genesis of epileptic discharges; in patients with ExTE-HSR, the concordance was 66%. CONCLUSIONS: DSC-MRI is a noninvasive procedure that may provide useful additional information to lateralize and/or localize the IEF when interictal epileptiform activity is sufficiently elevated.
BACKGROUND AND PURPOSE: Epidemiological studies have suggested a pathophysiological link between sleep apnea syndrome and cerebrovascular diseases. The mechanism by which sleep disturbance can affect the predisposition to developing stroke is not clear. The aim of this study was to investigate whether patients with obstructive sleep apnea syndrome have an increase in atherosclerosis indicators at the carotid artery level. METHODS: We included 23 male patients with severe obstructive sleep apnea syndrome (respiratory disturbance index >30). Intima-media thickness and the presence of steno-occlusive lesions in the common carotid arteries were investigated with B-mode high-resolution ultrasonography. Results of the ultrasonographic examination were compared with those of a group of 23 subjects without obstructive sleep apnea syndrome who were matched for age and comorbid factors. RESULTS: The intima-media thickness of the common carotid arteries of patients with obstructive sleep apnea syndrome was significantly higher (P<0.0001) than that of control subjects (1.429+/-0.34 versus 0.976+/-0.17 mm). CONCLUSIONS: Results of the present study show that carotid wall thickness is increased in patients with severe sleep apnea syndrome. There is strong evidence that an increase in the thickness of the carotid artery wall is a valid marker of the risk of stroke. For this reason, our finding seems to further strengthen the hypothesis that patients with obstructive sleep apnea syndrome are at risk of developing cerebrovascular diseases regardless of the association with other vascular risk factors.