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DeToledo JC, Ramsay RE. The mechanisms of the ocular autonomic dysfunction during the intracarotid amytal suppression test. Epilepsy Res 1997; 26:309-13. [PMID: 9095392 DOI: 10.1016/s0920-1211(96)00894-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We report the eye findings during selective injections of amytal to the internal carotid artery and to trunk and branches of the middle cerebral artery in three patients. This report comes a propos of our previous observation that fairly dense visual obscuration (probably secondary retinal suppression by the amytal), pupillary dilatation (mydriasis) and impairment of visual accommodation (cycloplegia) are not uncommon during the intracarotid amytal suppression test (AST). Selective injections in these three cases offered additional-insight into the mechanisms of the autonomic dysfunction observed in the eye ipsilateral to injection of amytal (EII). Injection of amytal into the trunk and branches of the middle cerebral artery, above the origin of the ophthalmic artery, did not produce ocular autonomic changes in any of the three patients. Injection of amytal in the internal carotid, below the origin of the ophthalmic artery, resulted in pupillary dilatation in the EII in two of the three patients. Based on the anatomy of the vasculature and autonomic innervation of the eye, we postulate that the pupillary dilatation and deficit of visual accommodation observed after intracarotid amytal injection are secondary to parasympathetic suppression in the ciliary ganglion. Amytal reaches the ciliary ganglion via the posterior ciliary arteries, branches of the ophthalmic artery. In summary, injection of amytal in the internal carotid artery below the origin of the ophthalmic artery, but not above it, can impair visual acuity and in some cases, entirel suppress the vision in the EII secondary to retinal suppression. Dilatation of the pupil due to parasympathetic dysfunction is also common and is likely secondary to suppression of the ciliary ganglion in the orbit.
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Nemire RE, Toledo CA, Ramsay RE. A pharmacokinetic study to determine the drug interaction between valproate and propranolol. Pharmacotherapy 1996; 16:1059-62. [PMID: 8947979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A 40-year-old female receiving divalproex sodium (VPA) monotherapy for epilepsy developed a tremor secondary to the drug. Propranolol treatment was initiated. While receiving propranolol 40 mg, VPA clearance was reduced from 1.66 L/hr to 1.19 L/hr and dropped to 1.08 L/hr on propranolol 80 mg. The mechanism of this interaction is unknown. To evaluate the potential for a drug interaction between these two agents, 12 patients on VPA monotherapy, ages 19-55, were studied. The subjects were maintained on a constant dose of VPA. Each was then randomly assigned to receive placebo, or long-acting propranolol 60 mg/day or 120 mg/day. Mean VPA serum concentrations did not change among the three groups. Plasma half-life of VPA ranged from 7.3-18 hours and did not change with coadministration of propranolol. We concluded that VFA metabolism is not affected by coadministration of propranolol in this group of patients.
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DeToledo JC, Ramsay RE. Patterns of involvement of facial muscles during epileptic and nonepileptic events: review of 654 events. Neurology 1996; 47:621-5. [PMID: 8797454 DOI: 10.1212/wnl.47.3.621] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We reviewed the patterns of involvement of the orbicularis oculi and other facial muscles during 654 events recorded in 257 patients undergoing telemetry evaluation. Four hundred fifty-seven episodes represented epileptic seizures and 197 represented psychogenic seizures. Eyes were wide open in more than 90% of patients during the tonic phase of a generalized tonic clonic seizure. Lowering of the lid with partial closure of the eye, without contraction of the orbicularis oculi, was the predominant form of eye closure we observed. Eye closure in any form was uncommon during the ictal stage of epileptic seizures with motor accompaniment and occurred in 21 of 408 cases and in 2 of 49 simple partial seizures somatosensory type. Sustained, forceful eye closure with active opposition to opening was present in 41 of 75 cases of psychogenic seizures with motor symptoms and in 16 of 21 cases of psychogenic unresponsiveness and was much less common with psychogenic seizures with pure sensory symptoms (8 of 72 cases). The mouth is usually wide open during the tonic phase of a generalized convulsion. The presence of a clenched mouth during a "tonic spell" should raise the possibility of psychogenic seizures. Injuries to the tongue due to biting during the epileptic seizures usually affect the side of the tongue. Biting of the lip or tip of the tongue was not seen with epileptic attacks and is also suggestive of psychogenic seizures.
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Wilder BJ, Campbell K, Ramsay RE, Garnett WR, Pellock JM, Henkin SA, Kugler AR. Safety and tolerance of multiple doses of intramuscular fosphenytoin substituted for oral phenytoin in epilepsy or neurosurgery. ARCHIVES OF NEUROLOGY 1996; 53:764-8. [PMID: 8759983 DOI: 10.1001/archneur.1996.00550080082016] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Safety, tolerability, and pharmacokinetics of fosphenytoin sodium, a water-soluble phenytoin prodrug, were investigated after a temporary substitution of intramuscular fosphenytoin for oral phenytoin sodium in 240 epileptic or neurosurgical patients taking oral phenytoin sodium (100-500 mg/d). METHODS Patients were randomly assigned to 1 of 2 parallel groups. During screening and follow-up, patients were maintained on a regimen of oral phenytoin at an individualized dose. During treatment, the phenytoin-treated patients received intramuscular placebo and their prescribed dose of oral phenytoin; the fosphenytoin-treated patients received oral placebo and intramuscular fosphenytoin equimolar to their phenytoin dose. RESULTS Both groups had similar types and frequencies of mild to moderate adverse events. Fosphenytoin was as well tolerated as intramuscular placebo at the injection site. Intramuscular fosphenytoin equimolar to a patient's oral phenytoin dose produced equal or greater plasma phenytoin concentrations. CONCLUSIONS Dosing adjustments are not required when intramuscular fosphenytoin is temporarily substituted or oral phenytoin therapy is resumed. Intramuscular fosphenytoin is a safe and well-tolerated alternative to oral phenytoin when oral administration is not feasible.
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Ramsay RE, DeToledo J. Intravenous administration of fosphenytoin: options for the management of seizures. Neurology 1996; 46:S17-9. [PMID: 8649609 DOI: 10.1212/wnl.46.6_suppl_1.17s] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Fosphenytoin is a water-soluble disodium phosphate ester of phenytoin that is converted in plasma to phenytoin. Fosphenytoin is compatible with most common i.v. solutions and can be administered safely through the i.m.route. An additional safety factor is the absence of propylene glycol in the fosphenytoin formulation. Propylene glycol is used as a vehicle in the i.v. phenytoin preparation and by itself may produce serious cardiovascular complications. Studies of the pharmacokinetics, safety, and tolerance of i.v. fosphenytoin have demonstrated that fosphenytoin produces phenytoin plasma concentrations similar to those achieved with oral and i.v. phenytoin, but without significant cardiovascular effects and only minimal discomfort at the injection site. Aside from local reactions, the most common adverse events associated with fosphenytoin have been pruritus and reactions typical of phenytoin (e.g., dizziness, somnolence, and ataxia). Fosphenytoin represents a significant advance in the treatment of patients with seizures who require parenteral therapy.
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Faught E, Wilder BJ, Ramsay RE, Reife RA, Kramer LD, Pledger GW, Karim RM. Topiramate placebo-controlled dose-ranging trial in refractory partial epilepsy using 200-, 400-, and 600-mg daily dosages. Topiramate YD Study Group. Neurology 1996; 46:1684-90. [PMID: 8649570 DOI: 10.1212/wnl.46.6.1684] [Citation(s) in RCA: 259] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We conducted a randomized double-blind comparison of three doses of the novel antiepileptic drug (AED) topiramate (200, 400, and 600 mg/day) and placebo as adjunctive therapy in patients with refractory partial onset epilepsy receiving one or two other AEDs at therapeutic concentrations. A total of 181 patients completed the 12-week baseline phase and were randomized to double-blind therapy. Median percent reductions from baseline in average monthly seizure rate, the principal efficacy evaluation, were 13% for placebo, 30% for topiramate 200 mg/day, 48% for topiramate 400 mg/day, and 45% for topiramate 600 mg/day. For the seizure rate comparison of active drug to placebo p values were: topiramate 200 mg/day, p = 0.051; topiramate 400 mg/day, p = 0.007; topiramate 600 mg/day, p < 0.001. Percent responders ( > or = 50% reduction in seizure rates) were 18% for placebo, 27% for topiramate 200 mg/day, 47% for topiramate 400 mg/day (p = 0.013), and 46% for topiramate 600 mg/day (p = 0.027). A significant (p = 0.003) reduction in secondarily generalized seizures compared with placebo treatment was also documented with topiramate. Topiramate plasma concentrations were closely related to dosage, and there were no significant interactions between topiramate and other AEDs. The minimal effective dose of topiramate in this study population was approximately 200 mg/day. Mild or moderate CNS symptoms were the primary treatment-emergent adverse events, but treatment-limiting adverse events occurred in only 9% of patients given topiramate compared with 7% given placebo. Results of this initial well-controlled study in patients indicate that topiramate is a very promising new AED.
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Abstract
Phenobarbital, diazepam, lorazepam, and phenytoin are all currently used for the treatment of acute seizures, including status epilepticus. None of these drugs is considered ideal. Fosphenytoin is a new phenytoin prodrug that fulfills many of the properties of an ideal anticonvulsant drug. The safety, tolerance, and pharmacokinetics of intramuscularly administered fosphenytoin have been evaluated in three clinical trials involving patients requiring loading or maintenance doses of phenytoin. These investigations demonstrated that fosphenytoin is rapidly and completely absorbed after injection into muscle and is quickly converted to produce therapeutic phenytoin plasma concentrations within 30 min of administration. Plasma concentrations of phenytoin achieved with i.m. fosphenytoin exceeded those associated with an equimolar dose of oral phenytoin. i.m. fosphenytoin was well tolerated both locally and systemically. Only mild and transient reactions occurred at the injection site. The most common systemic adverse events reported--somnolence, nystagmus, dizziness, and ataxia--are side effects commonly seen with phenytoin and tended to be mild. Preexisting seizure disorders remained stable. Combination treatment with i.v. diazepam or lorazepam to attain rapid seizure control and i.m. fosphenytoin to maintain the anticonvulsant effect theoretically offers many advantages for control of acute seizures and should be studied.
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Devinsky O, Leppik I, Willmore LJ, Pellock JM, Dean C, Gates J, Ramsay RE. Safety of intravenous valproate. Ann Neurol 1995; 38:670-4. [PMID: 7574466 DOI: 10.1002/ana.410380418] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This multicenter, open-label trial was designed to study the safety of intravenous (IV) sodium valproate in patients with epilepsy. All 318 patients (previously treated with antiepileptic drugs) were hospitalized for seizure control or anticipated seizures. The protocol allowed physicians to set the number of infusions and treatment duration. Adverse events, laboratory studies performed, and seizure activity were documented on case report forms. The patients' mean age was 34.4 years (range, 2-87 years). The most common reason for admission was lack of seizure control (235 patients, 185 of whom were admitted for video-electroencephalographic monitoring). The median dosage of valproate was 375 mg infused over 1 hour. The median number of doses was four, given over 2 days. In 54 patients (17%), transient adverse events were reported. The most frequent were headache, reaction at the injection site, and nausea (2.2% each); somnolence (1.9%); vomiting (1.6%); and dizziness and taste perversion (1.3% each). No persistent or severe hematologic or serum chemistry abnormalities were found. Vital signs were not significantly affected by the IV infusion of valproate. At the dosages and rates of administration studied, intravenous valproate appears to be safe and well tolerated.
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Abstract
For a 2-year period, all patients admitted to the inpatient adult EEG videotelemetry unit of the University of Miami School of Medicine underwent attempted event induction with intravenous normal saline placebo. Of 175 patients monitored during that period, 101 underwent attempted placebo saline induction, whereas 58 patients were either in the pediatric age group, were undergoing a repeat hospitalization (i.e., depth electrode monitoring), or refused induction. The final diagnosis in each patient was established after review of the history; physical, interictal, and ictal EEG findings; brain imaging studies; interictal and postictal brain single photon emission computed tomography (SPECT) and serum prolactin levels; psychiatric and psychological evaluations; and detailed neuropsychological testing. Final diagnoses were separated into epilepsy alone, pseudoseizures, epilepsy and pseudoseizures, and other (neither epilepsy nor pseudoseizures). No patient with an eventual diagnosis of epilepsy alone was inducible. Forty-one patients with a diagnosis of epilepsy were not inducible. Of 32 patients with an eventual diagnosis of pseudoseizures, 29 were inducible. One of these 29 was also diagnosed with epilepsy. Three patients with an eventual diagnosis of pseudoseizures were not inducible; 90.6% of patients with an eventual diagnosis of pseudoseizures were inducible, i.e., had events identical to those reported by history, after injection of saline placebo. Placebo saline injection is a safe and effective means of distinguishing epilepsy from pseudoseizures.
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Ben-Menachem E, Hamberger A, Hedner T, Hammond EJ, Uthman BM, Slater J, Treig T, Stefan H, Ramsay RE, Wernicke JF. Effects of vagus nerve stimulation on amino acids and other metabolites in the CSF of patients with partial seizures. Epilepsy Res 1995; 20:221-7. [PMID: 7796794 DOI: 10.1016/0920-1211(94)00083-9] [Citation(s) in RCA: 233] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Electrical stimulation of the vagus nerve (VNS) is a new method for the treatment of patients with medically intractable epilepsy. Sixteen patients, ten of whom participated in a larger multicenter double-blind trial on the efficacy of VNS in epilepsy, and six who participated in pilot studies, consented to participate in the present study. Ten patients received HIGH stimulation and six patients LOW stimulation for the 3-month trial. Cerebrospinal fluid (CSF) samples (16 ml) were collected both before and after 3 months of VNS. Amino acid and neurotransmitter metabolites were analyzed. Four patients responded to VS with more than a 25% seizure reduction after 3 months. Mean and median concentrations of phosphoethanolamine (PEA) increased in responders and decreased in nonresponders. Free GABA increased in both groups but more so in the nonresponders. After 9 months of VS (6-9 months on HIGH stimulation) 4 of 15 patients had more than 40% seizure reduction. There were significant correlations between seizure reduction and increases in asparagine, phenylalanine, PEA, alanine and tryptophan concentrations. Comparison between patients with HIGH or LOW stimulation showed a significant increase in ethanolamine (EA) in the HIGH group and a decrease in glutamine in the LOW group. All patients regardless of response or stimulation intensity showed significantly increased total and free GABA levels. A decrease in CSF aspartate was marginally significant. Other trends were decreases in glutamate and increases in 5-hydroxyindoleacetic acid. Chronic VNS appears to have an effect on various amino acids pools in the brain.(ABSTRACT TRUNCATED AT 250 WORDS)
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Ramsay RE. Clinical efficacy and safety of gabapentin. Neurology 1994; 44:S23-30; discussion S31-2. [PMID: 8022537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The challenges of treating patients with partial seizures soon will be met, in part, by a number of new additions (felbamate, gabapentin, lamotrigine) to existing treatment options. Gabapentin, has shown significant promise in the treatment of patients with refractory partial seizures and secondarily generalized tonic-clonic seizures. Three large, randomized, multicenter, double-blind, placebo-controlled, parallel-group clinical trials have established its efficacy and safety as add-on therapy in patients with refractory partial seizures. Gabapentin is well tolerated. Although adverse events occur in most patients receiving gabapentin as adjunctive therapy, they are transient and mild to moderate in severity. To date, serious adverse events have been rare. Long-term safety data are needed. The lack of drug interaction potential between gabapentin and traditional antiepileptic drugs also was confirmed in clinical trials.
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Ramsay RE, Uthman BM, Augustinsson LE, Upton AR, Naritoku D, Willis J, Treig T, Barolat G, Wernicke JF. Vagus nerve stimulation for treatment of partial seizures: 2. Safety, side effects, and tolerability. First International Vagus Nerve Stimulation Study Group. Epilepsia 1994; 35:627-36. [PMID: 8026409 DOI: 10.1111/j.1528-1157.1994.tb02483.x] [Citation(s) in RCA: 169] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Vagus nerve stimulation (VNS) significantly reduces the frequency of partial seizures in refractory epilepsy patients. We examined the serious adverse events, side effects, and tolerability as they relate to the surgical implant procedure and the stimulating device. We also reviewed potential drug interactions, device output complications, and impact of the therapy on overall health status. We analyzed the first 67 patients to exist the acute phase of the EO3 VNS trial comparing high (therapeutic) VNS to low (less or noneffective) VNS. Data were collected from case report forms used at each of the four visits during the 12-week baseline and at each of the four visits during the 14-week randomized phase of the trial. No significant complications were reported as a result of the implant procedure. Serious adverse events included 1 patient who experienced direct current to the vagus nerve owing to generator malfunction resulting in left vocal cord paralysis and withdrawal of the patient from the study. No clinically significant effects on vital signs, cardiac function, or gastric function were detected. Side effects associated with VNS in the high group were hoarseness (35.5%), coughing (13.9%), and throat pain (12.9%). In the low group, only hoarseness (13.9%) and throat pain (13.9%) were associated with VNS. These effects generally wrre not considered clinically significant and occurred primarily during the stimulation pulses. No patients discontinued VNS therapy during the acute phase because of side effects associated with normal stimulation. Except for the one instance of a short circuit in the system resulting in a direct current, stimulating system complications were minor, limited to programming, unscheduled stimulation, and high lead impedance. Patients, investigators, and patient companions rated patients receiving high stimulation as more "improved" than those receiving low stimulation in regards to overall health status. Antiepileptic drug (AED) plasma concentrations were not affected by VNS. The implant procedure, stimulating system, and therapy proved safe and tolerable during the study. The high percentage (67 of 68) of patients completing the study reflects patient acceptance and tolerability of this mode of therapy.
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Wu FY, Slater JD, Ramsay RE. Neural network approach in multichannel auditory event-related potential analysis. INTERNATIONAL JOURNAL OF BIO-MEDICAL COMPUTING 1994; 35:157-68. [PMID: 8005710 DOI: 10.1016/0020-7101(94)90073-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Even though there are presently no clearly defined criteria for the assessment of P300 event-related potential (ERP) abnormality, it is strongly indicated through statistical analysis that such criteria exist for classifying control subjects and patients with diseases resulting in neuropsychological impairment such as multiple sclerosis (MS). We have demonstrated the feasibility of artificial neural network (ANN) methods in classifying ERP waveforms measured at a single channel (Cz) from control subjects and MS patients. In this paper, we report the results of multichannel ERP analysis and a modified network analysis methodology to enhance automation of the classification rule extraction process. The proposed methodology significantly reduces the work of statistical analysis. It also helps to standardize the criteria of P300 ERP assessment and facilitate the computer-aided analysis on neuropsychological functions.
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Slater JD, Wu FY, Honig LS, Ramsay RE, Morgan R. Neural network analysis of the P300 event-related potential in multiple sclerosis. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1994; 90:114-22. [PMID: 7510626 DOI: 10.1016/0013-4694(94)90003-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Neural network analysis is sensitive to subtle changes in patterns of data. We hypothesized that a disease process which can cause impairment of cortical function such as multiple sclerosis (MS) would affect the P300 cognitive evoked potential (P300) in a manner detectable by a feedforward backpropagation neural network. Such a network was trained using a learning data set consisting of 101 P300 wave forms (from 26 MS patients and 26 normal controls). The network was then used to classify a randomly selected test data set of 20 studies (2 studies each of 5 MS patients and 5 controls) to which it had not been previously exposed, with an average accuracy (MS = abnormal, control = normal) of 81% for a single midline electrode, increasing to 90% using 3 midline electrodes in a jury system. Neural network analysis can be of help in distinguishing normal (control) P300 from abnormal (MS) P300.
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Messenheimer J, Ramsay RE, Willmore LJ, Leroy RF, Zielinski JJ, Mattson R, Pellock JM, Valakas AM, Womble G, Risner M. Lamotrigine therapy for partial seizures: a multicenter, placebo-controlled, double-blind, cross-over trial. Epilepsia 1994; 35:113-21. [PMID: 8112232 DOI: 10.1111/j.1528-1157.1994.tb02920.x] [Citation(s) in RCA: 161] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The efficacy and safety of lamotrigine (LTG), a new antiepileptic drug (AED), were evaluated in a multicenter, randomized, double-blind, placebo-controlled, cross-over study of 98 patients with refractory partial seizures. Each treatment period lasted 14 weeks. Most patients were titrated to a LTG maintenance dose of 400 mg/day. Seizure frequency with LTG decreased by > or = 50%, as compared with placebo, in one fifth of patients. Overall median seizure frequency decreased by 25% with LTG as compared with placebo (p < 0.001). With LTG, the number of seizure days decreased by 18% as compared with placebo (p < 0.01), and investigator global evaluation of overall patient clinical status favored LTG by 2:1 (p = 0.013). Plasma LTG concentrations appeared to be linearly related to dosage. LTG had no clinically important effects on the plasma concentrations of concomitant AEDs. Adverse experiences were generally minor and most frequently were CNS-related (e.g., ataxia, dizziness, diplopia, headache). Most were transient and resolved without discontinuing treatment. Five patients withdrew as a result of adverse experiences while receiving LTG, including 3 patients with rash. One placebo patient was also withdrawn because of rash. The addition of twice-daily LTG to an existing AED regimen was safe, effective, and well tolerated in these medically refractory partial seizure patients.
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Abstract
Three new antiepileptic drugs (AEDs) are likely to be approved in the United States by the Food and Drug Administration in the near future. In general, all three have good safety profiles, causing only mild, well-tolerated side effects. Felbamate (FBM) is effective in the treatment of partial seizures and Lennox-Gastaut epilepsy. FBM appears to have a broader spectrum of antiepileptic activity than carbamazepine (CBZ) or phenytoin (PHT). Gabapentin (GBP) was designed to be a structured analogue of gamma-aminobutyric acid (GABA). GBP is most effective in the maximal electroshock model of seizures but may have a different mechanism of action than CBZ and PHT. Unique pharmacokinetic properties (no hepatic metabolism and no protein binding) may make GBP especially useful for certain patients, such as those with hepatic disease and elderly patients who are receiving multiple medications. The overall profile of activity of lamotrigine (LTG) is similar to that of PHT and may act on voltage-sensitive sodium channels to stabilize neuronal membranes. LTG is effective in partial seizures, and there is some indication that LTG may be helpful in primary generalized seizures. The long half-life and lack of effect on other AEDs will make LTG easy to dose and add to a patient's existing regimen. These new agents will provide physicians with more effective medications from which to choose in the treatment of the patient with epilepsy.
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Uthman BM, Wilder BJ, Penry JK, Dean C, Ramsay RE, Reid SA, Hammond EJ, Tarver WB, Wernicke JF. Treatment of epilepsy by stimulation of the vagus nerve. Neurology 1993; 43:1338-45. [PMID: 8327135 DOI: 10.1212/wnl.43.7.1338] [Citation(s) in RCA: 151] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We treated 14 patients with medically refractory partial seizures by stimulation of the vagus nerve in two single-blind pilot studies. Patients received stimulation through an implantable, programmable NeuroCybernetic Prosthesis, consisting of a pulse generator and a lead-electrode assembly. The mean reduction in seizure frequency after 14 to 35 months of vagal stimulation was 46.6%. Of the 14 patients, five (35.7%) had a 50% or greater reduction in seizure frequency. Two patients, one of whom had had 10 to 100 seizures per day before stimulation, have been seizure-free for over 1 year. Adverse events were primarily limited to initial hoarseness and a tingling sensation at the electrode site in the neck when the device was activated. Most patients tolerated the device and stimulation well. There were no permanent adverse events. Some cases of medically refractory partial seizures are improved by vagal stimulation.
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Brown MC, Levin BE, Ramsay RE, Landy HJ. Comprehensive evaluation of left hemisphere type I schizencephaly. ARCHIVES OF NEUROLOGY 1993; 50:667-9. [PMID: 8503805 DOI: 10.1001/archneur.1993.00540060093027] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We report the neuropsychological, magnetic resonance imaging, electroencephalographic telemetry, and sodium amytal test findings of a 32-year-old, left-handed man with unilateral left hemisphere type I schizencephaly. The patient was referred for treatment of medically refractory left temporal complex partial seizures that developed at age 26 years. Sodium amytal testing revealed complete incorporation of speech and language function by the right hemisphere. Detailed neuropsychological evaluation indicated average to above-average performance on all measures of language skills, judgment and reasoning, visuospatial abilities, and memory function. This case demonstrates that extensive but lateralized neuronal migration disorders can be associated with complete reorganization and full recovery of function by the contralateral hemisphere. Furthermore, this case supports the view that the degree of recovery is greatest when compensatory mechanisms are activated antenatally.
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Wu FY, Slater JD, Honig LS, Ramsay RE. A neural network design for event-related potential diagnosis. Comput Biol Med 1993; 23:251-64. [PMID: 8334865 DOI: 10.1016/0010-4825(93)90024-u] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Many diseases resulting in neuropsychological impairment show abnormalities by EEG (electroencephalogram) tests. However, EEG analysis is complicated by a wide spectrum of normal patterns. Cerebral evoked potentials are stimulus-induced, averaged EEG potentials that have been found useful in patients with dementing illness. A recent report using the P300 auditory evoked potential shows that simple latency and waveform criteria result in classification accuracy of 65% for multiple sclerosis (MS) patients versus 91% for control subjects. Analysis on the same data set was performed using an artificial neural network (ANN) and a nearest neighbor (NN) classifier. An ANN classifier demonstrated a classification accuracy of 75% versus 87% on MS and control subject groups. Thus prediction accuracy was improved on average, compared with that obtained by NN classifiers or P300 statistical analysis. The classification strategy discovered by a trained ANN was analyzed by a weight pattern analysis method and compared with the P300 latency criteria.
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Faught E, Sachdeo RC, Remler MP, Chayasirisobhon S, Iragui-Madoz VJ, Ramsay RE, Sutula TP, Kanner A, Harner RN, Kuzniecky R. Felbamate monotherapy for partial-onset seizures: an active-control trial. Neurology 1993; 43:688-92. [PMID: 8469323 DOI: 10.1212/wnl.43.4.688] [Citation(s) in RCA: 141] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We evaluated felbamate (FBM) monotherapy in 111 patients with uncontrolled partial-onset seizures in a multicenter, double-blind, parallel-group trial. During the 56-day baseline period, patients had at least eight partial-onset seizures and received one standard antiepileptic drug (AED) at a therapeutic level; a second AED was allowed if at a subtherapeutic level. Patients received either FBM 3,600 mg/d or valproate (VPA) 15 mg/kg/d. The baseline AED at therapeutic levels was discontinued by one-third decrements on study days 1, 14, and 28 and the sub-therapeutic AED, if any, was discontinued completely on study day 1. Study endpoints were completion of 112 study days or fulfilling one or more escape criteria. Criteria for escape relative to baseline were (1) twofold increase in monthly seizure frequency, (2) twofold increase in highest 2-day seizure frequency, (3) single generalized tonic-clonic seizure (GTC) if none occurred during baseline, or (4) significant prolongation of GTCs. The primary efficacy variable was the number of patients in each treatment group who met escape criteria. Thirty-seven patients on VPA and 18 on FBM met escape criteria (p < 0.001). Even when we considered FBM dropouts to have fulfilled escape criteria and VPA dropouts to have completed the 112-day trial, the treatment difference remained statistically significant (p = 0.039) in favor of FBM. Adverse experiences with FBM were all mild or moderate in severity. The frequency of adverse experiences was much lower during monotherapy. FBM monotherapy was effective in the treatment of partial-onset seizures with or without secondarily generalized seizures and demonstrated a favorable safety profile.
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Landy HJ, Curless RG, Ramsay RE, Slater J, Ajmone-Marsan C, Quencer RM. Corpus callosotomy for seizures associated with band heterotopia. Epilepsia 1993; 34:79-83. [PMID: 8422866 DOI: 10.1111/j.1528-1157.1993.tb02379.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Band heterotopia is a severe form of neuronal migration disorder associated with intractable epilepsy and neurologic impairment. Surgical treatment of seizures associated with this malformation has not been reported previously. We report a patient with band heterotopia and poorly controlled atonic seizures causing falls and injury. The patient was treated with anterior corpus callosotomy, with significant postoperative decrease in seizure frequency. Corpus callosotomy is a reasonable alternative to consider in management of patients with cortical heterotopia and intractable seizures.
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Abstract
Status epilepticus, particularly the convulsive form, is a medical emergency, warranting prompt and aggressive treatment. To do this, one must have a thorough understanding of the pharmacology of the anticonvulsant agents. Therapy should be directed toward rapid termination of the status epilepticus, prevention of seizure recurrence, and treatment of any underlying cause. Most importantly, one should establish and adhere to a standard treatment protocol for best results.
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Landy HJ, Ramsay RE, Slater J, Casiano RR, Morgan R. Vagus nerve stimulation for complex partial seizures: surgical technique, safety, and efficacy. J Neurosurg 1993; 78:26-31. [PMID: 8416238 DOI: 10.3171/jns.1993.78.1.0026] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Electrical stimulation of the vagus nerve has shown efficacy in controlling seizures in experimental models, and early clinical trials have suggested possible benefit in humans. Eleven patients with complex partial seizures were subjected to implantation of vagus nerve stimulators. Electrode contacts embedded in silicone rubber spirals were placed on the left vagus nerve in the low cervical area. A transcutaneously programmable stimulator module was placed in an infraclavicular subcutaneous pocket and connected to the electrode. One patient required replacement of the system due to electrode fracture. Another patient developed delayed ipsilateral vocal-cord paralysis; the technique was then modified to allow more tolerance for postoperative nerve edema. A third patient showed asymptomatic vocal-cord paresis on immediate postoperative laryngoscopy. Vagus nerve stimulation produces transient vocal-cord dysfunction while the current is on. Nine patients were randomly assigned to receive either high- or low-current stimulation, and seizure frequency was recorded. The high-current stimulation group showed a median reduction in seizure frequency of 27.7% compared to the preimplantation baseline, while the low-current stimulation group showed a median increase of 6.3%. This difference approached statistical significance. The entire population then received maximally tolerable stimulation. The high-current stimulation group showed a further 14.3% reduction, while the low-current stimulation group showed a 25.4% reduction compared to the blinded period. The efficacy of vagus nerve stimulation seemed to depend on stimulus parameters, and a cumulative effect was evident. These results are encouraging, and further study of this modality as an adjunct treatment for epilepsy is warranted.
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Landy HJ, Ramsay RE, Ajmone-Marsan C, Levin BE, Brown J, Pasarin G, Quencer RM. Temporal lobectomy for seizures associated with unilateral schizencephaly. SURGICAL NEUROLOGY 1992; 37:477-81. [PMID: 1595054 DOI: 10.1016/0090-3019(92)90139-e] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Schizencephaly is characterized by unilateral or bilateral cerebral clefts associated with neurologic deficits and epilepsy. Most commonly schizencephaly is attributed to abnormal neuronal migration, and these malformations are well visualized by current neuroimaging techniques. This report describes a patient with unilateral schizencephaly and poorly controlled complex partial seizures who was found to have a temporal lobe seizure focus; anterior temporal lobectomy produced nearly complete control of the seizures. Despite the extensive malformation, relatively restricted resection was of significant benefit. The principles of seizure focus localization and resection are applicable to the management of patients with schizencephaly.
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