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Biomedical subjects

S A Musumeci

Publications and source records attributed to S A Musumeci.

At least 19 recordsLinked to original sources
PubMed2001

Transient MRI abnormalities associated with partial status epilepticus: a case report.

We report the case of an 18-year-old woman who presented a long-lasting cluster of partial seizures, and MRI cortical abnormalities localized in the left parietal lobe. The MRI changes correlated with the site of the epileptogenic focus, and disappeared within 2 weeks. The recognition of these reversible MRI abnormalities, which are presumably due to a temporary alteration of blood-brain barrier in the epileptogenic zone with subsequent edema, and are not associated with any underlying organic conditions, is extremely useful in the medical management of the patient and allows to avoid other invasive diagnostic procedures.

Adolescent↗
PubMed2001

Relationship between Delta, Sigma, Beta, and Gamma EEG bands at REM sleep onset and REM sleep end.

OBJECTIVE: The aim of the present study was to analyze in detail the relationship of two newly introduced measures, related to the Beta and Gamma EEG bands during REM sleep, with Delta and Sigma activity at REM sleep onset and REM sleep end, in order to understand their eventual role in the sleep modulation mechanism. METHODS: For this purpose, power spectra of 1 EEG channel (C4, referred to A1) were obtained by means of the fast Fourier transform and the power of the bands ranging 0.75-4.50 Hz (Delta), 4.75-7.75 (Theta), 8.00-12.25 (Alpha), 12.50-15.00 (Sigma), 15.25-24.75 (Beta), 25.00-34.75 (Gamma 1), and 35.00-44.75 (Gamma 2) was calculated for the whole period of analysis (7 h), in 10 healthy subjects. Additionally, two other time series were calculated: the ratio between Beta and Gamma2, and between Gamma1 and Gamma2 (Beta and Gamma ratios). For each subject, we extracted 3 epochs of 30 min corresponding to the 15 min preceding and the 15 min following the onset of the first 3 REM episodes. Data were then averaged in order to obtain group mean values and standard deviation. The same process was applied to the 30-min epochs around REM sleep end. RESULTS: The course of the Delta band around REM sleep onset was found to be characterized by a first phase of slow decline lasting from the beginning of our window up to a few seconds before REM onset; this phase was followed by a sudden, short decrease centered around REM onset, lasting for approximately 1.5-2 min. At the end of this phase, the Delta band reached its lowest values and remained stable up to the end of the time window. The Sigma band showed a similar course with stable values before and after REM sleep onset. The Beta and Gamma ratios also showed a 3-phase course; the first phase, in this case, was characterized by stable low values, from the beginning of our window up to approximately 5 min before REM onset. The following second phase was characterized by an increase which reached its maximum shortly after REM sleep onset (approximately 1 min). In the last phase, both Beta and Gamma ratios showed stable high values, up to the end of our time window. At REM sleep end, the Delta band only showed a very small gradual increase, the Sigma band presented a more evident gradual increase; on the contrary, both Beta and Gamma ratios showed a small gradual decrease. CONCLUSIONS: The results of the present study show a different time synchronization of the changes in the Delta band and in Beta and Gamma ratios, at around REM sleep onset, and seem to suggest that the oscillations of these parameters might be modulated by mechanisms more complex than a simple reciprocity. All these considerations point to the fact that REM sleep can be considered as a complex phenomenon and the analysis of high-frequency EEG bands and of our Beta and Gamma ratios represent an additional important element to include in the study of this sleep stage.

Adult↗
PubMed2001

Non-linear EEG analysis in children with epilepsy and electrical status epilepticus during slow-wave sleep (ESES).

OBJECTIVE: The objective of this work was to study the non-linear aspects of electroencephalography (EEG) in children with epilepsy and electrical status epilepticus during slow-wave sleep (ESES). METHODS: In this study, we recorded the sleep EEG in 5 subjects with ESES (4 males and one female, aged 6.5-10 years) who were also mentally retarded and affected by cerebral palsy (3 subjects) and hydrocephalus (two subjects). The signals were sampled at 128Hz and stored on hard disk. All the subsequent computational steps were performed on EEG epochs (4096 data points) selected from wakefulness and non-rapid eye movement (non-REM) (with ESES) or REM sleep. The dynamic properties of the EEG were assessed by means of the non-linear cross prediction (NLCP) test which uses 3 different 'model' time series in order to predict non-linearly the original data set (Pred, Ama and Tir). Pred is a measure of the predictability of the time series and Ama and Tir are measures of asymmetry, indicating non-linear structure. Moreover, the correlation dimension (D2) was estimated by means of the algorithm by for the epochs showing non-linear nature. RESULTS: The NLCP test provided evidence of significant non-linear dynamics in all epochs of non-REM sleep, when ESES was evident. Only during this stage, the possible presence of low-dimensional chaos could also be suspected (average D2=4.02; range 3.16-6.21). EEG without ESES could not be distinguished from linearly filtered noise. CONCLUSIONS: The results of the present study seem to indicate that subjects with ESES show a profound modification of their EEG dynamics with the occurrence, during sleep, of long periods characterized by non-linear dynamics and, probably, low-dimensional chaotic structure able to modify in a substantial way their brain functioning during sleep.

Child↗
PubMed2001

Somatosensory evoked potentials in patients affected by unilateral cerebrovascular lesions with onset during the perinatal period or adulthood.

Unilateral cerebrovascular lesions occurring during adulthood have been reported to be accompanied by high-amplitude somatosensory evoked potentials over the nonaffected hemisphere; however, the mechanisms by which somatosensory evoked potential amplitude increases over the nonaffected hemisphere are still unclear. To investigate the eventual presence of similar amplitude abnormalities in children, we recorded somatosensory evoked potentials in three groups of patients: one with unilateral cerebrovascular lesions that occurred during the perinatal period and another two with unilateral cerebrovascular lesions occurring during late adulthood or old age. Group 1 was comprised of 12 children and young adults (age range 2 3/12-31 years, 6 males and 6 females) who suffered from unilateral cerebrovascular lesion with perinatal onset. Four control groups were arranged with age matched to that of the patients. Adult patients were subdivided into two subgroups (group 2: n = 10, all males; group 3: n = 18, 12 males and 6 females) on the basis of the presence or absence of sensory impairment over the hemiplegic side. In group 1, the four youngest subjects, aged less than 6 years, were found to show somatosensory evoked potentials of abnormally high amplitude over the nonaffected hemisphere, with a "giant" main negative wave at around 45 ms (range 38.7-49.2), strictly localized over the central areas contralateral to the lesion; in normal controls, there was no such wave. All patients in group 2 were found to be affected by large infarctions in the territory of the middle cerebral artery, whereas patients in group 3 presented with subcortical lesions of the internal capsule isolated or in association with an involvement of the frontal and/or temporal cortex. Regarding somatosensory evoked potential parameters measured over the nonaffected hemisphere in adult/elderly subjects, a significant difference was observed for N20 and P22 latency, which was longer in both groups of patients than in controls. There is a significant difference in the neurophysiologic consequences of unilateral cerebrovascular lesion, as well as over the nonaffected hemisphere, if it occurs during early infancy or during adulthood. Our findings show a new type of "giant" somatosensory evoked potentials in some children affected by unilateral cerebrovascular lesion with perinatal onset.

Adolescent↗
PubMed2000

Topiramate potentiates the antiseizure activity of some anticonvulsants in DBA/2 mice.

Topiramate (1-50 mg/kg, intraperitoneally (i.p.)) was able to antagonize audiogenic seizures in DBA/2 mice in a dose-dependent manner. Topiramate at dose of 2.5 mg/kg i.p., which per se did not significantly affect the occurrence of audiogenic seizures in DBA/2 mice, potentiated the anticonvulsant activity of carbamazepine, diazepam, felbamate, lamotrigine, phenytoin, phenobarbital and valproate against sound-induced seizures in DBA/2 mice. The degree of potentiation induced by topiramate was greatest for diazepam, phenobarbital and valproate, less for lamotrigine and phenytoin and not significant for carbamazepine and felbamate. The increase in anticonvulsant activity was associated with a comparable increase in motor impairment. However, the therapeutic index of the combination of all drugs+topiramate was more favourable than that of antiepileptics+ saline, with the exception of carbamazepine or felbamate+topiramate. Since topiramate did not significantly influence the total and free plasma levels of the anticonvulsant drugs studied, we suggest that pharmacokinetic interactions, in terms of total or free plasma levels, are not probable. However, the possibility that topiramate can modify the clearance from the brain of the anticonvulsant drugs studied cannot be excluded. In addition, topiramate did not significantly affect the hypothermic effects of the anticonvulsants tested. In conclusion, topiramate showed an additive effect when administered in combination with some classical anticonvulsants, most notably diazepam, phenobarbital, lamotrigine, phenytoin and valproate.

Acoustic Stimulation↗
PubMed2000

Eyelid myoclonia with absences in three subjects with mental retardation.

Eyelid myoclonia with absences is a rare epileptic syndrome, characterized by eyelid myoclonia, absences, and photosensitivity. On the basis of its clinical and EEG features, this syndrome has been classified as a specific new entity among the idiopathic generalized epilepsies. We report three subjects, aged 4, 16, and 31 years, respectively, with eyelid myoclonia, and absences, mental retardation and other abnormalities of the central nervous system. Our findings suggest that, at least in some cases, eyelid myoclonia and absences can represent a peculiar phenomenon of symptomatic epilepsies.

Adolescent↗
PubMed2000

Sleep in subjects with autistic disorder: a neurophysiological and psychological study.

Polysomnography (EOG, EEG, EMG) was carried out in 17 male children and adolescents with autistic disorder, in seven patients with mental retardation and fragile X syndrome, and in five age- and sex-matched normal male subjects. Density of rapid eye movements was not significantly different in the three groups of subjects; however, some sleep parameters such as time in bed, sleep period time, and total sleep time were significantly lower in subjects with autistic disorder than in normal controls; moreover, patients with autistic disorder showed values of sleep period time, first REM latency and percent (%) sleep stage 1 lower than those of patients with fragile X syndrome with mental retardation. Density of muscle twitches was significantly higher in patients with autistic disorder than in normal controls. In contrast only minor differences were observed between patients with autistic disorder and those with fragile X syndrome with mental retardation. Furthermore, some psychoeducational profile-revised items such as perception and eye-hand coordination, showed significant correlation with some sleep parameters (time in bed, sleep latency, stage shifts, first REM latency and wakefulness after sleep onset). Childhood Autism Rating Scale (CARS) scores to visual response and non-verbal communication showed significant correlation with some tonic sleep parameters, such as sleep period time, wakefulness after sleep onset, and total sleep time. Relating to people and activity level items were found to be significantly correlated with rapid eye movement density. Our results suggest the existence of a sleep pattern in autistic patients different from that observed in subjects with mental retardation and from that of normal controls. In addition, these findings indicate that sleep parameters in these patients are correlated with some psychological indices generally used for the diagnosis of autistic disorder; for this reason, polysomnographies might be useful in the comprehension of the neurophysiological mechanisms underlying this condition.

Adolescent↗
PubMed2000

The time course of high-frequency bands (15-45 Hz) in all-night spectral analysis of sleep EEG.

OBJECTIVE: The EEG spectral content of all-night sleep recordings obtained in 7 healthy young subjects, aged 18-20 years, including frequencies up to 45 Hz, was studied in order to detect eventual changes in the high-frequency range similar to those reported by magnetic field recording during REM sleep at 40 Hz. METHODS: For this purpose, power spectra were calculated with a fast Fourier transform and the power of the bands ranging 0.75-4.50 Hz (Delta), 4.75-7.75 (Theta), 8.00-12.25 (Alpha), 12.50-15.00 (Sigma), 15.25-24.75 (Beta), 25.00-34.75 (Gamma1), and 35.00-44.75 (Gamma 2) was calculated for-the whole period of analysis (7 h). Also two additional time series: the ratio between Beta and Gamma2, and between Gamma1 and Gamma2 were calculated (Beta and Gamma ratios). RESULTS: Beta and Gamma1 showed small changes with a tendency to increase during REM sleep; Gamma2, on the contrary, showed small changes with a tendency to decrease during REM sleep. Beta and Gamma ratio peaks were clearly correlated with the occurrence of REM sleep. The small changes shown by Beta, Gamma1 and Gamma2 were not statistically significant; on the contrary, Beta ratio and Gamma ratio showed the most important statistical significance values being highest during REM sleep and lowest during slow-wave sleep. Finally, the calculation of the linear correlation coefficient and of the cross-correlation between the different bands showed a clear reciprocity between Delta and Beta and Gamma ratios. CONCLUSIONS: Our study shows a new method for the analysis of high frequencies (up to 45 Hz) in the scalp-recorded sleep EEG which allowed us to better define, as compared to previous studies on the same topic, the changes in power characteristically associated with REM sleep and correlated with the REM/non-REM ultradian rhythm, and to propose it as a tool for future studies.

Activity Cycles↗
PubMed2000

Does a peculiar EEG pattern exist also for FRAXE mental retardation?

OBJECTIVE: FRAXE mental retardation, a recently identified rare genetic condition, is due to a mutation of the FMR2 gene, located at Xq28 region. The phenotype is non-specific and characterized by developmental delay, speech, reading and writing problems, poor adaptive skills, anxiety, aggressiveness, obsessive-compulsive disturbance, and hyperactivity. The objective of this study was to describe the characteristic EEG pattern found in one patient with FRAXE mental retardation. METHODS: EEG (with photic stimulation and hand/foot tapping) and median nerve somatosensory evoked potentials were recorded in a 8-year-old male patient with FRAXE mental retardation (diagnosis confirmed by molecular genetic analysis) and speech disturbances. RESULTS: The patient never presented seizures; however, sleep enhanced multifocal spikes were found in the EEG. Moreover, tactile stimulation of hands and feet, as well as intermittent photic stimulation, provoked the appearance of spikes. Somatosensory evoked potentials from the median nerves showed a 'giant' component at around 60 ms. CONCLUSIONS: Considering the rarity of both FRAXE mental retardation and tactile evoked spikes, their association in the same subject might be considered as not casual. If confirmed by future studies, these neurophysiological findings might be considered as a marker for FRAXE mental retardation.

Brain↗
PubMed2000

Age-related changes of cortical excitability in subjects with sleep-enhanced centrotemporal spikes: a somatosensory evoked potential study.

Middle-latency somatosensory evoked potentials (SEPs) of particularly large amplitude (giant) have been reported in subjects with benign childhood epilepsy with centrotemporal spikes (BECT) and in normal children, which usually show significant age-related changes. However, the mechanisms by which age modifies the appearance of centrotemporal spikes and giant SEPs in these children, are not known. The characteristics of SEPs were studied in a group of 18 subjects (10 males and 8 females, aged 7.1-17.2 years) with sleep-enhanced centrotemporal spikes, with or without BECT and the results were compared with those obtained from a group of age-matched normal controls. Giant SEPs were recorded in 6 subjects and, in 3 of these, EEG spikes evoked by hand tapping were obtained also. No subjects with giant SEPs were found in subjects older than 12 years, and an age-related decrease in amplitude of giant SEPs as this age approached was observed. Moreover, at repeated SEP recordings, a clear trend towards a more important reduction in amplitude of giant SEPs over the temporal and parietal than over the central regions was evident. The study of EEG spikes evoked by hand tapping showed a striking similarity between the averaged evoked spikes and the main negative component of giant SEPs. It was also possible to observe that the spike negative peak recorded over the central areas always preceded the same component recorded over the parietal and temporal areas by 5-15 ms. Our study seems to support the idea that giant SEPs in subjects with centrotemporal spikes are generated by a complex mechanism different from that at the basis of the normal N60 component of SEPs; they also show peculiar age-related modifications which can be interpreted in terms of maturational changes of brain excitability/inhibition and probably constitute a tool for monitoring the clinical course of BECT, when present.

Adolescent↗
PubMed2000

Cyclic alternating pattern and spectral analysis of heart rate variability during normal sleep.

The natural arousal rhythm of non-rapid eye movement (NREM) sleep is known as the cyclic alternating pattern (CAP), which consists of arousal-related phasic events (Phase A) that periodically interrupt the tonic theta/delta activities of NREM sleep (Phase B). The complementary condition, i.e. non-CAP (NCAP), consists of a rhythmic electroencephalogram background with few, randomly distributed arousal-related phasic events. Recently, some relation between CAP and autonomic function has been preliminarily reported during sleep in young adults by means of spectral analysis of heart rate variability (HRV). The present study was aimed at analysing the effects of CAP on HRV in a group of normal children and adolescents. Six normal children and adolescents (age range 10.0-17.5 y) were included in this study. All-night polygraphic recordings were performed after adaptation to the sleep laboratory. Six 5-min epochs were selected from sleep Stage 2 and six from Stages 3 and 4 (slow-wave sleep), both in CAP and NCAP conditions. From such epochs, a series of parameters describing HRV was then calculated, in both time and frequency domains, on the electrocardiographic R-R intervals. Statistical comparison between CAP and NCAP epochs revealed a significant difference for most of the frequency domain parameters (increase of the low-frequency band, increase of the low-frequency/high-frequency ratio and decrease in the high-frequency band during CAP) both in Stage 2 and in slow-wave sleep. Our results demonstrate that the physiological fluctuations of arousal during sleep described as CAP are accompanied by subtle, but significant, changes in balance between the sympathetic and vagal components of the autonomic system.

Adolescent↗
PubMed2000

Audiogenic seizures susceptibility in transgenic mice with fragile X syndrome.

PURPOSE: To evaluate their susceptibility to audiogenic seizures, five groups of knockout mice with various forms of fragile X genetic involvement [hemizygous males (n = 46), and homozygous (n = 38) and heterozygous females (n = 45), and their normal male (n = 45) and female (n = 52) littermates] were studied. METHODS: All mouse groups were tested at ages 17, 22, 35, and 45 days. Audiogenic seizure susceptibility was scored, and the analysis of variance was used for the evaluation of the effects of age and genetic condition on seizure severity score (SSS). RESULTS: All groups of knockout fragile X mice exhibited SSSs significantly higher than those observed in their wild-type littermates; among knockout mice, hemizygous males and homozygous females showed the highest SSSs. Hemizygous males showed higher SSSs with increasing age, from 17 to 45 days; homozygous females showed a peak at age 22 days, followed by a decrease; finally, heterozygous females had their highest SSSs at age 17 days. CONCLUSIONS: This study demonstrates that an increased susceptibility to audiogenic seizures is present in fragile X knockout mice at all the ages tested. These results support the validity of this animal model also for epilepsy and seizures in the human fragile X syndrome.

Acoustic Stimulation↗
PubMed2000

Clinical correlates of brain morphometric features of subjects with low-functioning autistic disorder.

Numerous neuropathologic and imaging studies have reported different structural abnormalities in the brains of autistic subjects. However, whether or not the degree of brain abnormality is correlated with the severity of developmental impairment in autistic disorder is still unknown. The midsagittal area of the cerebrum, corpus callosum, midbrain, cerebellar vermis, and vermal lobules VI and VII was measured by means of magnetic resonance imaging in 22 boys with low-functioning autistic disorder and in 11 age-matched normal controls. Morphometric measures were statistically compared between groups and correlated with age and scores on the Psychoeducational Profile-Revised and the Childhood Autism Rating Scale. A significant negative correlation was found between midsagittal area of the cerebrum and age in patients with autistic disorder, and a positive correlation was found between the midsagittal area of the midbrain and some subscales of the Psychoeducational Profile-Revised.

Adolescent↗
PubMed1999

Epilepsy and EEG findings in males with fragile X syndrome.

PURPOSE AND METHODS: One hundred and ninety-two fragile X male patients were investigated for seizures and EEG findings, 168 in a retrospective and 24 in another prospective study, to characterize the natural history of seizures, epilepsy, and EEG abnormalities in males with this syndrome. RESULTS: Seizures were documented in 35 (18.2%) of 192 patients; they never started before the age of 2 years or after the age of 9 years. Seizures were frequently of the complex partial type and less frequently of the partial motor and generalized type. Seizures involving frontal and temporal lobes were commonly seen and were usually well controlled by anticonvulsants. In the majority of young fragile X patients studied, an age-related paroxysmal EEG pattern was found, which showed neurophysiologic characteristics very similar to those of the centrotemporal spikes. CONCLUSIONS: These findings confirm that fragile X syndrome can be considered a genetic model of epilepsy.

Adolescent↗
PubMed1999

Seizures in Chiari I malformation: a clinical and electroencephalographic study.

Seven subjects with Chiari I malformations and seizures (four males, three females; age range 11 years, 7 months to 36 years; mean, 22.28 +/- 7.58 years; median, 21) were identified in four different centers from among a group of 10 patients. Our aim was to analyze clinical and electroencephalographic characteristics of seizures in this etiologically homogeneous group of patients. Most of the seizures were of the complex partial type, and paroxysmal abnormalities were mainly localized over the frontal and temporal regions. The course of the epilepsy was rather benign, with complete control of seizures in four patients and an important reduction in frequency in the remaining three subjects. Other cortical alterations are not usually associated with the typical abnormalities of the posterior fossa in Chiari I malformation; thus, it is possible to hypothesize that cerebral microdysgenesis or, alternatively, a cerebellar dysfunction could underlie epileptogenesis in these patients.

Adolescent↗