Self-induction of visually-induced seizures.
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Adult↗
Biomedical subjects
C A Tassinari
Publications and source records attributed to C A Tassinari.
Gaze-evoked amaurosis heralding orbital angiomyoma. Case report.
The unusual case of a patient presenting with gaze-evoked amaurosis as an early and isolated sign of orbital angiomyoma is reported. Computed tomography or magnetic resonance of the orbits need to be expeditiously performed in patients with gaze-evoked amaurosis in order to identify or rule out the possible presence of an underlying tumor.
Angiomyoma↗
Motor evoked responses to paired cortical magnetic stimulation in Parkinson's disease.
We evaluated cortical excitability in patients with Parkinson's disease (PD) using paired magnetic stimulation. This recent technique allows to study the cortical inhibition after motor evoked potential (MEP) and its modulation at different intensities of stimulation and interstimulus intervals (ISIs). At low stimulus intensity and at ISIs of 40-75 ms we observed, in PD patients, a greater test MEP inhibition, which might be due to a lower facilitatory effect of conditioning MEP on the motor cortex. At high stimulus intensity, in PD patients, a consistent inhibition of test MEP persisted and, at ISIs of 75-150 ms, it did not reach the amplitude of conditioning MEP as in normal subjects. Some clinical and neurophysiological features, like a silent period of shorter duration, demonstrated in PD patients a decrease of the inhibitory input to the motor cortex. On the contrary, the persistence of test-MEP inhibition at high stimulus intensity could also suggest a prevalence of inhibitory activity when an effective and phasic activation of the corticospinal system is required.
Aged↗
Unstable minisatellite expansion causing recessively inherited myoclonus epilepsy, EPM1.
Progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1; MIM 254800) is an autosomal recessive disorder that occurs with a low frequency in many populations but is more common in Finland and the Mediterranean region. It is characterized by stimulus-sensitive myoclonus and tonic-clonic seizures with onset at age 6-15 years, typical electroencephalographic abnormalities and a variable rate of progression between and within families. Following the initial mapping of the EPM1 gene to chromosome 21 (ref. 6) and the refinement of the critical region to a small interval, positional cloning identified the gene encoding cystatin B (CST6), a cysteine protease inhibitor, as the gene underlying EPM1 (ref. 10). Levels of messenger RNA encoded by CST6 were dramatically decreased in patients. A 3' splice site and a stop codon mutation were identified in three families, leaving most mutations uncharacterized. In this study, we report a novel type of disease-causing mutation, an unstable 15- to 18-mer minisatellite repeat expansion in the putative promoter region of the CST6 gene. The mutation accounts for the majority of EPM1 patients worldwide. Haplotype data are compatible with a single ancestral founder mutation. The length of the repeat array differs between chromosomes and families, but changes in repeat number seem to be comparatively rare events.
Cystatin B↗
A neurophysiological study in children and adolescents with Crigler-Najjar syndrome type I.
We studied the neurophysiological features of five patients (age range: 4-20 years) suffering from Crigler-Najjar syndrome type I (CNsI) by means of multimodal (brainstem, somatosensory, motor) evoked potentials and periodic EEG-polygraphic recordings (follow-up: 3 months-4.5 years). Two patients presented with neurological disturbances, consisting mainly of mental slowing, motor impairment and seizures. Both of them presented an abnormal EEG, characterized by slowing of background activity associated with paroxysmal discharges. Liver transplantation was performed in one of these two patients and was followed by improvement of both the neurological picture and EEG activity. In a third patient, clinically normal, after two years of follow-up, the EEG started to show paroxysmal activity during sleep or when evoked by intermittent photic stimulation. In these three patients, multimodal evoked potentials were unremarkable. The remaining two younger subjects did not show any clinical or EEG abnormality. Our findings suggest that, whereas in newborns and infants evoked potentials have been demonstrated as reliable techniques to monitor bilirubin neurotoxicity, in children and adolescents with CNsI, EEG seems to be more sensitive in evaluating patients for neurological damage and effectiveness of therapeutic strategies adopted.
Adolescent↗
Double-blind, placebo-controlled trial of topiramate (600 mg daily) for the treatment of refractory partial epilepsy.
PURPOSE: We wished to evaluate adjunctive therapy for partial-onset seizures with topiramate (TPM) for efficacy and safety in a double-blind, placebo-controlled, randomized, parallel-group study. METHODS: Sixty outpatients with epilepsy (47 men and 13 women, mean age 32.9 years) were studied. All had a documented history of partial-onset seizures with or without secondarily generalized seizures. After an 8-week baseline during which patients had at least one seizure per week, 30 patients each were randomized to TPM 300 mg twice daily (b.i.d.) or placebo for 12 weeks. RESULTS: TPM was significantly superior to placebo, as indicated by all efficacy assessments: greater median percent reduction from baseline in the average monthly seizure rate (46 vs. -12%, p = 0.004); greater number of treatment responders (patients with > or = 50% reduction in seizure rate) (47 vs. 10%, p = 0.001), and better investigator (p = 0.002) and patient (p = 0.010) global assessments of treatment. Among TPM-treated patients, the most commonly reported adverse events (AE) were headache, somnolence, fatigue, dizziness, and abnormal thinking. Most AE were mild or moderate in severity. CONCLUSIONS: The results of the present trial indicate that TPM 600 mg/day is effective in the treatment of refractory partial-onset seizures with or without secondarily generalized seizures.
Adolescent↗
Reduced plasma nisoldipine concentrations in phenytoin-treated patients with epilepsy.
PURPOSE: To assess whether phenytoin affects the pharmacokinetics of the dihydropyridine calcium antagonist nisoldipine. METHODS: Twelve patients with epilepsy receiving chronic phenytoin therapy and 12 healthy control subjects matched for age and gender received a single oral dose of nisoldipine (40 and 20 mg, respectively). Blood samples were collected for up to 48 h for estimation of plasma nisoldipine levels by capillary gas chromatography. RESULTS: Mean plasma nisoldipine concentrations were much lower in the patients. Geometric means for areas under the concentration-time curve (AUC0-tn) normalized to a 20-mg dose were 1.6 micrograms/L/h (95% confidence intervals, 0.6-3.8 micrograms/L/h) in the patients compared with 15.2 (10.7-21.6) micrograms/L/h in control subjects (p < 0.002). CONCLUSIONS: These results suggest that phenytoin increases the first-pass metabolism of nisoldipine to a clinically important extent. In view of the magnitude and variability of interaction, use of nisoldipine in patients receiving chronic phenytoin therapy is contraindicated.
Adult↗
Transcranial magnetic stimulation in partial epilepsy: drug-induced changes of motor excitability.
Single-pulse transcranial magnetic stimulation (s-TMS) with recording of motor evoked potentials (MEPs) from thenar muscles of both hands was performed on 84 patients with cryptogenic partial epilepsy and 50 healthy controls. We analyzed the cortical latency (CL), central conduction time (CCT), and threshold intensity (TI) required to elicit liminal MEPs at rest. In the patients, CL and CCT were normal, but TI was significantly higher than in the controls. Of the 84 patients, 65 were taking one or more antiepileptic drugs and 19 were untreated. The untreated patients had a significantly lower TI than the treated patients. In the treated patients, the TI increase paralleled the number of drugs taken. Additionally, in 2 subgroups of patients undergoing major modifications of antiepileptic treatment, TI dropped after partial withdrawal of medication and increased following the commencement of therapy. The results suggest that anticonvulsants depress the excitability of human motor pathways in epileptic subjects.
Adolescent↗
Electroclinical features of idiopathic generalised epilepsy with persisting absences in adult life.
OBJECTIVES: To describe the electroclinical features of typical absences persisting in adult life. METHODS: Twelve adult patients (aged 21 to 56 years) with idiopathic generalised epilepsy featuring typical absences as the prominent clinical feature were studied. All patients underwent a full clinical and neurophysiological investigation including ictal documentation of seizures. RESULTS: Neurological examination and neuroradiological investigations were normal in all cases. Clinical findings included a median age at onset of absences of 14 (range 4-32) years, almost constant tonic-clonic seizures (in 83% of patients), frequent episodes of absence status (in 33% of patients), and associated cognitive or psychiatric disturbances. Interictal EEG findings showed normal background activity, generalised paroxysms of spike waves or polyspike waves, and inconstant focal spikes (in five patients); runs of polyspikes were seen during non-REM sleep. Ictal EEG findings showed generalised spike waves at 3 Hz, sometimes preceded by multiple spikes, or more complex EEG patterns with sequences of polyspikes intermingled with spike waves or polyspike waves, showing discharge fragmentation or variation of intradischarge frequency. CONCLUSION: The results of the present study show that absences persisting in adult life may show particular clinical and EEG patterns, distinct from those in childhood or adolescence.
Adult↗
Frontal inhibitory spike component associated with epileptic negative myoclonus.
The aim of this study was to characterize paroxysmal EEG activities associated with epileptic negative myoclonus (ENM) in an epileptic patient presenting with ENM. ENM was predominant in the right upper limb and was correlated to a spike in the left central region. Spikes associated with ENM (SaENM) and spikes unrelated to ENM (SuENM) were identified by the temporal relation between the left central spike and the EMG silent period in the right wrist extensor. SaENM showed a significantly longer duration than SuENM (128 +/- 27 msec versus 92 +/- 21 msec, respectively; P < 0.01). SaENM and SuENM were submitted to spike averaging and topographic mapping. Spike averaging was performed averaging the EEG 640 msec before and after the peak of the spike. Both averaged SaENM and SuENM consisted of a negative spike with highest amplitude at C3 and similar topographic characteristics. The discriminant feature between the two types of spikes was the presence, in averaged SaENM, of a second smaller negative spike, 40 msec after the peak of the spike at C3, whose maxima were distributed over the left frontal region. We labeled this second spike as ENM-related component. We conclude that, in our patient, ENM was associated with a frontal cortical potential suggesting the involvement of frontal areas in the generation of negative myoclonus.
Adult↗
Transient cognitive impairment due to glioblastoma.
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Amnesia↗
Corticospinal tract degeneration in motor neuron disease.
Long-repetition-time spin-echo MR images showed symmetric hyperintensity of the intracerebral corticospinal tracts in two patients with clinical and neurophysiologic diagnosis of primary lateral sclerosis and amyotrophic lateral sclerosis. In both, axial low-flip-angle gradient-echo images of the cervical spine showed hyperintensity of the lateral columns of the cord consistent with antegrade degeneration of the crossed corticospinal tracts.
Adult↗
Epileptic negative myoclonus.
ENM is an etiologically heterogeneous disorder clinically evident as brief (less than 500 msec) lapses of tonic muscular contraction which seems to be related to lesions or dysfunction of different anatomofunctional levels of the CNS (Fig. 13). ENM can occur in heterogeneous epileptic disorders, ranging from benign syndromic conditions (such as BECTS) to focal static lesional epilepsy, as in neuronal migration disorders, and even to severe static or progressive myoclonic encephalopathies (PMEs). Neurophysiological studies in patients with ENM lead to the following conclusions: 1. A cortical origin of ENM is supported by EEG mapping and dipole analysis of spikes related to the ENM. In particular, our data suggest that the focal spike is a paroxysmal event involving, primarily or secondarily, the centroparietal and frontal "supplementary" motor areas. 2. A cortical inhibitory active mechanism for the genesis of ENM is supported by the occurrence of a decreased motor response to TMS, with preserved spinal excitability as demonstrated by the persistence of F waves. A "cortical motor outflow inhibition" related to spike-and-wave discharges was suggested by Gloor in his Lennox lecture (34). The cortical reflex negative myoclonus, described by Shibasaki et al. (16) in PME, is also consistent with a cortical active inhibitory mechanism. The spike associated with ENM raises new issues about the definition of "interictal" versus "ictal" EEG paroxysmal activity. A single spike on the EEG can be clinically silent (therefore, "interictal") or clinically evident as ENM (then viewed as "ictal"), depending on whether a given group of muscles is at rest or is showing tonic activity (see Fig. 4). These data, from a more general perspective, imply that the motor manifestation related to EEG paroxysmal events can depend not only on amplitude, topography, or intracortical distribution of seizure activity (35), but also on plasticity (36) and on the functional condition of the motor system (37). The variability of latency between the spike and the onset of the muscular inhibition (ranging from 15 to 50 msec, for the upper limbs), and the variability of duration of the ENM itself (from 50 to 400, or more, msec) indicate that ENM could be the result of inhibitory phenomena arising not only from a single cortical "inhibitory" area, but also from subcortical and pontine structures, as discussed by Mori et al. (this volume). The neurophysiological distinction between ENM and postmyoclonic periods of muscular suppression, mainly related to an EGG slow wave, as described by Lance and Adams (2) in the postanoxic action myoclonus is still a matter of discussion (38, 39). This is also the case for other movement disorders combining action myoclonus and epilepsy-as described in Ramsay Hunt syndrome (30), now better referred to as Unverricht-Lundborg syndrome (40) (Fig. 14). In these conditions, myoclonia and muscular silent periods are inconstantly associated with paroxysmal EEG discharges, suggesting a possible thalamocortical mechanism rather than a purely cortical one. In the most prolonged muscular inhibitions, both cortical and thalamocortical mechanisms might be implicated. Clearly, our knowledge of ENM is still very limited and gaining further insights into this complex phenomenon is a challenging problem.
Brain Mapping↗
PME of Unverricht-Lundborg type in the Mediterranean region: linkage and linkage disequilibrium confirm the assignment to the EPM1 locus.
Seven phenotypically homogeneous Mediterranean myoclonus families were studied using DNA markers from the genetically defined EPM1 region on chromosome 21. No recombinations between the disease phenotype and the markers studied were detected. Within the EPM1 region, the highest lod score value of 5.07 (at theta = 0.00) was reached at locus PFKL. Significant allelic association (P = 0.02) between the disease mutation and PFKL was detected suggesting a founder effect in Mediterranean myoclonus. However, haplotype data using four marker loci residing within 300 kb of each other and of EPM1 suggest the occurrence of more than one mutation. The data are compatible with Mediterranean myoclonus being caused by mutations in the EPM1 gene and strengthen the concept that a large subset of progressive myoclonus epilepsies conforms with Unverricht-Lundborg disease and that this subset is an etiologically homogeneous entity.
Adolescent↗
Pattern of motor evoked response to repetitive transcranial magnetic stimulation.
The changes in motor pathway excitability, induced by pairs or trains of transcranial magnetic stimuli, were studied. The motor evoked potential (MEP) pattern depended on the interstimulus interval (ISI), the stimulus intensity and the type of coil employed. At low intensity, using either an 8-shaped or a circular coil, there was a test MEP inhibition at ISIs of 50-150 msec. During trains of stimuli, this inhibition showed a periodic trend with an interval of 250-300 msec. At high stimulus intensity we observed a progressive disappearance of test MEP inhibition which was incomplete with an 8-shaped coil and complete, reaching an MEP facilitation, with a circular coil. The inhibition observed at low intensity might be due to cortical inhibitory mechanisms. The effect found at high intensity and with the circular coil could depend on the activation of deeper and at higher threshold cortico-spinal structures. This hypothesis, however, does not explain the simultaneous delay of the test MEP latency which might depend on the activation of different cortico-spinal pathways.
Adult↗
Amyloid deposits inside myocardial fibers in transthyretin-Met30 familial amyloidotic polyneuropathy. A histological and biochemical study.
A case of severe cardiac involvement is reported in a patient affected with familial amyloidotic polyneuropathy due to the Portuguese type I variant (Val-->Met30) of the transthyretin (prealbumin) molecule. Echocardiographic and hemodynamic studies suggested the presence of a progressive infiltrative cardiomyopathy that was later confirmed by endomyocardial biopsy. Amyloid deposits were found in both intra- and extra-myofiber location and thought to be related to primary involvement of the heart. Norepinephrine content of myocardial bioptic specimens was about threefold lower than normal, indicating that autonomic denervation may contribute to the maintenance and progression of cardiomyopathy. A sample obtained from the sural nerve showed a loss of myelinated fibers along with accumulation of amyloid masses in the endoneurial space. This histopathologic pattern correlated with a sharp decrease in the activity of the enzyme subserving electrochemical conduction through the axonal membrane, Na+, K(+)-ATPase.
Amyloid↗
Rapid-rate transcranial magnetic stimulation and hemispheric language dominance: usefulness and safety in epilepsy.
We performed rapid-rate transcranial magnetic stimulation (r-TMS) in 14 epileptic patients, using a coil centered over nine different positions on each side of the scalp and while the subjects counted aloud. We obtained lateralized speech arrest, concordant with the site of manual preference, in only seven patients. There was transitory homonymous hemianopia (one patient), brief jerking of one arm (two patients), and affective (crying) reaction (three patients) after the end of a train of stimuli. In our experience, r-TMS is not as sensitive as previously reported for determination of hemispheric language dominance and may have undesirable side effects.
Adult↗
Vigabatrin-induced decrease in serum phenytoin concentration does not involve a change in phenytoin bioavailability.
The possibility that vigabatrin (VGB) decreases serum phenytoin (PHT) concentration by lowering the oral bioavailability of PHT was investigated in 21 patients with epilepsy. Each patient was switched from oral to intravenous PHT for 5 days before and after combined treatment with VGB. After VGB (2-3.5 g day(-1) for at least 5 weeks), serum PHT concentrations decreased slightly from 87 +/- 25 to 76 +/- 31 micromol l(-1) (means +/- s.d., P < 0.05), but in a subgroup of seven patients the decrease was more prominent (from 72 +/- 22 to 49 +/- 17 micromol l(-1), P < 0.005). At baseline (before VGB), serum PHT remained unaffected (85 +/- 30 micromol l(-1)) after switching PHT dosage to the intravenous route, indicating that the oral availability of the drug was virtually complete. During VGB treatment, serum PHT was also unchanged (74 +/- 34 micromol l(-1)) after switching from oral to intravenous therapy, and this was also true for the subgroup of patients showing a prominent interaction (48 +/- 18 micromol l(-1)). The urinary recoveries of PHT and its metabolites pHPPH and mHPPH remained constant throughout the study. It is concluded that the oral availability of PHT is unaffected by VGB and that the VBG-induced decrease in serum PHT is mediated by alternative mechanisms.
Adolescent↗