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Biomedical subjects

G Plazzi

Publications and source records attributed to G Plazzi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Validation of symptoms related to excessive daytime sleepiness.

The aim of this study was to validate some recurring definitions of excessive daytime sleepiness (EDS) obtained from descriptive epidemiological studies. We devised questions concerning concepts such as "tiredness", "resistible sleepiness", "irresistible sleepiness" and "sudden sleep attacks". The validation was done by comparing the answers with the results of the Multiple Sleep Latency Test (MSLT), considered the gold standard, or criterion measure, for the diagnosis of EDS. The sample study comprised 73 subjects, 57 outpatients referred to our Sleep Center complaining of daytime sleepiness, snoring or sleep apnea and 16 inpatients admitted to our Neurological Institute for causes other than sleep disorders. A moderate correlation (p = -0.38, 95% confidence interval -0.57 to -0.19) was found between "irresistible sleepiness" and mean sleep latency (MSL). The best combinations of sensitivity and specificity in identifying EDS, for 5- and 8-min MSL cutoffs, were observed for the questions concerning "sudden sleep attacks" and "irresistible sleepiness" (areas under the receiver-operating characteristic curves = 66 and 67%, respectively). The subitems exploring the frequency and situations of occurrence of these symptoms improved the validity in identifying EDS. The items regarding "tiredness" and "resistible sleepiness" were not related to the results of the MSLT. In subgroup analysis, irresistible sleepiness failed to identify pathologic MSLT in sleep-disordered breathing subjects. According to previous observations, we suggest that the concept of sleepiness includes various domains heterogeneously related with MSL and that questionnaires must be tailored to the different populations studied.

Adolescent↗
PubMed2000

From nocturnal paroxysmal dystonia to nocturnal frontal lobe epilepsy.

Nocturnal paroxysmal dystonia (NPD) is the term used to describe motor attacks characterized by complex behavior, with dystonic-dyskinetic or ballic movements arising from NREM sleep. NPD together with paroxysmal arousals (PA), the briefest attacks, and episodic nocturnal wanderings (ENW), the most prolonged ones, constitute nocturnal frontal lobe epilepsy (NFLE). PA are sudden awakenings associated with stereotyped dystonic-dyskinetic movements, sometimes accompanied by screaming and a frightened expression. ENW are episodes of agitated ambulation, with complex, sometimes violent, motor behavior and dystonic postures involving head, trunk and limbs. NPD, PA and ENW coexist in most patients. NFLE is predominant in males and usually begins during adolescence. A familial recurrence of parasomnias in NFLE patients is much more common than in the general population. Autosomal dominant inheritance has been documented in 6% of our cases. Few patients present personal antecedents or positive neuroradiological findings. Seizures are frequent, occurring every or almost every night, many times per night. Interictal wake and sleep EEG tracings are often normal and ictal epileptic activity is recorded in a relatively small number of cases. Carbamazepine controls or significantly reduces seizures in about 70% of cases; the remainder are drug-resistant. Videopolysomnographic recordings, showing stereotyped abnormal movements during attacks, are mandatory to confirm the diagnosis of NFLE.

Epilepsy, Frontal Lobe↗
PubMed2000

Focal myoclonus and propriospinal propagation.

OBJECTIVE: To investigate the relationship between axial segmental myoclonus and propriospinal myoclonus. METHODS: A patient with a 3-year history of axial jerks evoked by physical effort and unexpected somesthetic and auditory stimulations was investigated. Polygraphy with multiple-channel axial and limb EMG recording was performed with off-line analysis. RESULTS: Spontaneous, somesthetic and acoustic evoked jerks always began in the left rectus abdominis muscle with a single or repetitive EMG burst that could spread to other rostral and caudal muscles without engagement of cranial nerve innervated muscles, consistent with propriospinal propagation. Spontaneous and evoked jerks could however also appear focally in abdominal muscles and remain localized without any diffusion to other muscle segments. CONCLUSION: Focal axial myoclonus and propriospinal myoclonus may coexist. Conceivably the same spinal generator responsible for a monomeric segmental myoclonus may, under conditions of heightened excitability, cause a multimeric propriospinally propagated muscular activation.

Adult↗
PubMed2000

Sleep stage-related changes in sympathetic sudomotor and vasomotor skin responses in man.

OBJECTIVES: The aim of the study was to evaluate the characteristics of the spontaneous and evoked sympathetic skin responses (SSR) during sleep and wakefulness in comparison with the skin vasomotor responses (SVR). METHODS: Five healthy subjects underwent a night of videopolysomnographic recording. Spontaneous SSR were recorded via surface electrodes placed on the dorsal and ventral aspect of the hand while SVR were evaluated by means of an infrared photoelectric transducer placed on the index finger. SSR and SVR were evoked via electrical stimuli applied to the left supraorbital nerve. RESULTS: Spontaneous SSR frequency was highest during stage 4 of NREM sleep and lowest during REM phases. On the contrary, spontaneous SVR frequency reached its lowest value during stage 4 and its highest value during stage 2 of NREM sleep, remaining at levels above waking values during REM. SSR could be elicited by stimuli inducing arousal during light sleep but it was absent during deep NREM and REM sleep. SVR could be evoked throughout NREM and REM sleep. CONCLUSIONS: Spontaneous SSR and SVR act differently during physiological modifications of vigilance. Evoked SSR is strictly dependent upon the state of vigilance, whereas evoked SVR shows no modifications during the different stages of the wake-sleep cycle.

Adult↗
PubMed1999

Bilateral centrotemporal spikes triggered by blinking: an unusual form of sensory input with related cortical EEG activity.

OBJECTIVE: To investigate the morphology, scalp topography and temporal relationship with orbicularis oculi muscle contraction of bilateral blink related spikes (BRS) in a 7-year-old boy with chromosomopathy, mild mental retardation and left spontaneous centrotemporal spikes (SS). METHODS: The patient underwent video-polygraphic recordings with off-line analysis of SS and BRS by means of spike-averaging and orbicularis oculi contraction-locked averaging techniques respectively. EEG activity related to reflex blinking (evoked by glabellar tapping) was also studied. RESULTS: SS and BRS presented the same morphology, characterised by four peaks (P1, N1, P2, N2). SS were located over the left centroparietal regions, while BRS were placed over both left and right centrotemporoparietal regions and constantly followed the contraction of orbicularis oculi with overlapping peak latencies over C3 and C4 electrodes (P1 72 ms; N1 115 ms; P2 164 ms; N2 236 ms). Reflex blinking evoked a small waveform with the same features as BRS. CONCLUSIONS: Our findings suggest that both involuntary and reflex blinking can act as a form of sensory stimulation probably engaging similar nervous pathways and cortical sources in generating EEG abnormalities: the trigeminal system.

Action Potentials↗
PubMed1999

Nocturnal frontal lobe epilepsy. A clinical and polygraphic overview of 100 consecutive cases.

Nocturnal frontal lobe epilepsy (NFLE) has been delineated as a distinct syndrome in the heterogeneous group of paroxysmal sleep-related disturbances. The variable duration and intensity of the seizures distinguish three non-rapid eye movement-related subtypes: paroxysmal arousals, characterized by brief and sudden recurrent motor paroxysmal behaviour; nocturnal paroxysmal dystonia, motor attacks with complex dystonic-dyskinetic features; and episodic nocturnal wanderings, stereotyped, agitated somnambulism. We review the clinical and polysomnographic data related to 100 consecutive cases of NFLE in order to define the clinical and neurophysiological characteristics of the different seizure types that constitute NFLE. NFLE seizures predominate in males (7:3). Age at onset of the nocturnal seizures varies, but centres during infancy and adolescence. A familial recurrence of the epileptic attacks is found in 25% of the cases, while 39% of the patients present a family history of nocturnal paroxysmal episodes that fit the diagnostic criteria for parasomnias. A minority of cases (13%) have personal antecedents (such as birth anoxia, febrile convulsions) or brain CT or MRI abnormalities (14%). In many patients, ictal (44%) and interictal (51%) EEGs are uninformative. Marked autonomic activation is a common finding during the seizures. NFLE does not show a tendency to spontaneous remission. Carbamazepine completely abolishes the seizures in approximately 20% of the cases and gives remarkable relief (reduction of the seizures by at least 50%) in another 48%. VideoEEG recordings confirm that NFLE comprises a spectrum of distinct phenomena, different in intensity but representing a continuum of the same epileptic condition. We believe that the detailed clinical and videoEEG characterization of patients with NFLE represents the first step towards a better understanding of the pathogenic mechanisms and different clinical outcomes of the various seizure types that constitute the syndrome.

Adolescent↗
PubMed1998

Autosomal dominant nocturnal frontal-lobe epilepsy: genetic heterogeneity and evidence for a second locus at 15q24.

Autosomal dominant nocturnal frontal-lobe epilepsy (ADNFLE) is a recently identified partial epilepsy in which two different mutations have been described in the alpha4 subunit of the neuronal nicotinic acetylcholine receptor (CHRNA4). An additional seven families are presented in which ADNFLE is unlinked to the CHRNA4 region on chromosome 20q13.2. Seven additional sporadic cases showed no evidence of defective CHRNA4. One of the families showed evidence of linkage to 15q24, close to the CHRNA3/CHRNA5/CHRNB4 cluster (maximum LOD score of 3.01 with D15S152). Recombination between ADNFLE and CHRNA4, linkage to 15q24 in one family, and exclusion from 15q24 and 20q13.2 in others demonstrate genetic heterogeneity with at least three different genes for ADNFLE. The CHRNA4 gene and the two known CHRNA4 mutations are responsible for only a minority of ADNFLE. Although the ADNFLE phenotype is clinically homogeneous, there appear to be a variety of molecular defects responsible for this disorder, which will provide a challenge to the understanding of the basic mechanism of epileptogenesis.

Chromosome Mapping↗
PubMed1998

Endozepine stupor. Recurring stupor linked to endozepine-4 accumulation.

Recurring stupor can be caused by repeated metabolic, toxic or structural brain disturbances. Recently, cases of recurring stupor, with fast EEG activity were shown to display increased endogenous benzodiazepine-like activity during the episodes of stupor. Patients with recurring stupor underwent extensive metabolic and toxicologic screening, EEG and brain imaging. Endozepines and exogenously administered benzodiazepines were assayed in plasma and CSF by means of mass spectrometry. Flumazenil, a benzodiazepine antagonist was administered and the behavioural and EEG responses monitored. Treatment with oral flumazenil was attempted in selected cases. Twenty patients were found with recurring stupor. Episodes had begun between ages 18 and 67 years, and in nine patients, had disappeared spontaneously after 4-6 years with symptoms. Stupor lasted hours or days. Onset of the episodes and frequency were unpredictable. Patients were normal between attacks. Stupor was characterized by initial drowsiness, staggering and behavioural changes, followed by deep sleep and spontaneous recovery with post-ictal amnesia. Biochemical screening and brain imaging were always normal. Ictal EEG showed fast background activity, and flumazenil transiently awoke the patients and normalized the EEG. In the nine cases examined, endozepine-4 levels were increased during the stupor. Oral flumazenil reduced the frequency of the attacks in three of these nine patients. Recurring episodes of stupor may be due to increased endozepine-4. We propose the term 'endozepine stupor' for such episodes. Endozepine-4 is an endogenous ligand for the benzodiazepine recognition site at the GABAA receptor, with unknown molecular structure.

Adult↗
PubMed1998

Clinical features of fatal familial insomnia: phenotypic variability in relation to a polymorphism at codon 129 of the prion protein gene.

Fatal Familial Insomnia is a hereditary prion disease characterized by a mutation at codon 178 of the prion protein gene cosegregating with the methionine polymorphism at codon 129 of the mutated allele. It is characterized by disturbances of the wake-sleep cycle, dysautonomia and somatomotor manifestations (myoclonus, ataxia, dysarthria, spasticity). PET studies disclose severe thalamic and additionally cortical hypometabolism. Neuropathology shows marked neuronal loss and gliosis in the thalamus, especially the medio-dorsal and anterior-ventral nuclei, olivary hypertrophy and some spongiosis of the cerebral cortex. Detailed analysis of 14 cases from 5 unrelated families showed that patients ran either a short (9.1 +/- 1.1 months) or a prolonged (30.8 +/- 21.3 months) clinical course according to whether they were homozygote met/met or heterozygote met/val at codon 129. Moreover, homozygotes had more prominent oneiric episodes, insomnia and dysautonomia at onset, whereas heterozygotes showed ataxia and dysarthria at onset, earlier sphincter loss and epileptic Grand Mal seizures; they also displayed more extensive cortical involvement on PET and at postmortem examination. Our data suggest that the phenotype expression of Fatal Familial Insomnia is related, at least partly, to the polymorphism at codon 129 of the prion protein-gene.

Adult↗
PubMed1998

REM sleep behaviour disorder differentiates pure autonomic failure from multiple system atrophy with autonomic failure.

Ten patients with primary autonomic failure, followed up in a prospective clinical and laboratory study, were finally diagnosed as pure autonomic failure or multiple system atrophy with autonomic failure. Polysomnographic studies were performed in all patients. Whereas all four patients with multiple system atrophy complained of sleep related episodes suggesting REM sleep behaviour disorder (RBD) confirmed by polysomnography, RBD remained absent in the remaining six patients with pure autonomic failure. The data indicate that RBD is an important clinical feature, often heralding multiple system atrophy, but which is absent throughout the course of pure autonomic failure; its recognition can thus be useful in the prognostic evaluation of early primary autonomic failure syndromes.

Adult↗
PubMed1997

Propriospinal myoclonus upon relaxation and drowsiness: a cause of severe insomnia.

Three patients, aged 71, 50, and 41 years, presented with myoclonic activity arising in the relaxation period preceding sleep onset and causing severe insomnia. Polygraphic studies showed that the myoclonic activity began in spinally innervated muscles, propagating at low speed to rostral and caudal muscular segments. Myoclonus arose whenever patients relaxed mentally and showed diffuse electroencephalographic alpha activity and was independent of posture. The jerks disappeared during sleep. Clonazepam afforded symptomatic improvement. Propriospinal myoclonus arising from a spinal generator may be facilitated by changes in supraspinal control related to vigilance levels. When arising during relaxation and drowsiness, it may cause severe insomnia.

Adult↗
PubMed1997

Endozepine stupor in children.

Recurring episodes of stupor in adults have been shown to be related to increased levels of endozepines, which are endogenous ligands for the GABAA receptors. We report here two children presenting with recurrent episodes of stupor associated with fast EEG activity who had increased levels of endozepine-4 in plasma. Mass spectroscopy did not reveal commercially available benzodiazepines. Interictal endozepine-4 levels were normal. In one of the patients, administration of flumazenil (0.25 mg i.v.), a benzodiazepine inverse agonist, induced improvement of consciousness and attenuation of EEG fast activity. In conclusion, children presenting with recurrent episodes of stupor and EEG fast activity should be evaluated for endozepine levels and can be effectively treated with i.v. flumazenil.

Carrier Proteins↗
PubMed1997

Motor overactivity and loss of motor circadian rhythm in fatal familial insomnia: an actigraphic study.

The 24-hour rest-activity pattern and the amount of motor activity was studied in a patient with fatal familial insomnia (FFI) by means of wrist actigraphy. During the study, the patient underwent indirect calorimetry. The 52-day recording showed severe disruption of the 24-hour rest-activity pattern with increased motor activity up to 80%. The 24-hour energy expenditure, assayed in a respiration chamber, was strikingly elevated by 60%. Chronic motor overactivity and loss of circadian rest-activity rhythm may play a role in the progressive metabolic exhaustion leading to death in FFI patients.

Body Mass Index↗
PubMed1997

Undiagnosed sleep-disordered breathing among male nondippers with essential hypertension.

OBJECTIVE: A blunting of the nocturnal fall in arterial blood pressure is found in a minority of patients (nondippers) with essential hypertension. We tested whether sleep-disordered breathing (snoring and apnea or hypopnea) might explain such a finding for male patients, among whom its prevalence is much higher. SETTING AND PATIENTS: We studied 100 new cases of hypertension in men, observed consecutively by a local group of general practitioners and diagnosed essential hypertensives in a referral clinic. By using 24 h ambulatory blood pressure monitoring with a SpaceLabs 90207 device, 15 patients were classified initially nondippers (daytime ambulatory blood pressure > or = 136/87 mmHg; night-time decrease by < 10% of the daytime mean), but only 11 were confirmed to be nondippers by continuous blood pressure monitoring with a Finapres device. Ten dippers matched by age, body mass index and mean 24 h blood pressure were used as controls. MAIN OUTCOME MEASURES: Parameters of nocturnal polysomnography. RESULTS: During polysomnography, the nondippers exhibited a blunting of the sleep-related fall in blood pressure and an increased variability in blood pressure associated with sleep-disordered breathing (heavy snoring for all, with an apnea or hypopnea index > 10 in 10 cases). Six of the control patients breathed normally and four snored nonapneically. There was a normal fall in nocturnal blood pressure in all 10 cases. CONCLUSIONS: The nondipper condition appears to be associated with undiagnosed apneic snoring for an unselected population of previously untreated male subjects with a diagnosis of essential hypertension. Ambulatory blood pressure monitoring of such patients is of limited diagnostic value.

Adult↗