Maria A. Gieron

Outpatient seizure identification : results of 502 patients using computer-assisted ambulatory EEG

Summary Patients with epilepsy may not always be able to identify their seizures. Epilepsy management relies on patient reporting to validate whether seizures occur during treatment. The goal of this study was to assess the frequency of unreported seizures recorded during routine outpatient ambulatory EEG recording. The authors reviewed 552 records from 502 patients who underwent outpatient 16-channel computer-assisted ambulatory EEG monitoring (CAA-EEG). Seizure identification was evaluated by assessing push-button activation. Partial seizures were seen most commonly. A total of 47 of 552 records (8.5%) had partial seizures recorded on CAA-EEG, with 29 of 47 (61.7%) with electroclinical seizures identified by push-button activation. Seizures on EEG without push-button activation were analyzed separately and compared with a self-reported written diary to verify lack of recognition. A total of 18 of 47 records (38.3%) had some partial seizures that were unrecognized by the patient, and 11 of 47 records (23.4%) had seizures recognized only by the computer. The authors conclude that patients frequently have seizures outside of the hospital that go unrecognized. Underreporting of seizure frequency occurs in the outpatient setting and impacts optimal diagnosis and treatment for patients with epilepsy.

Idiopathic generalized epilepsy and choice of antiepileptic drugs

The authors reviewed 58 patients with EEG-confirmed idiopathic generalized epilepsy (IGE). When initially seen, 17 (29%) were on broad-spectrum (adequate) antiepileptic drugs (AED) only, 28 (48%) on ill-advised AED only, and 13 (22%) on a combination of both. Thus, a majority of patients with IGE initially receive ill-advised AED, which cause IGE to appear intractable.

Nerve and muscle vulnerability to ischemia

Nerve and muscle vulnerability to structural damage during ischemia was examined in the hind legs of 50 cats after transient simultaneous clamping of the aorta and femoral artery for 1 to 10 h. Not until 5 h of ischemia were mild necrotic changes noted in nerves. Moderate to severe changes occurred after 8 h of ischemia. Contrariwise, mild muscle necrotic changes developed after 2-3 h, and moderate to severe changes after 5-7 h. The anterior tibialis muscle was usually more severely damaged than the gastrocnemius and soleus muscles. These studies demonstrate that: Longer periods of ischemia are required to produce nerve damage than suggested by previous tourniquet compression experiments. Longer periods of ischemia are necessary to produce necrosis in the posterior than anterior and lateral compartment muscles of the leg. Muscle is more vulnerable than nerve to ischemia.

MRI of the brain is safe in patients implanted with the vagus nerve stimulator

Metallic devices generally represent a contra-indication for MRI scanning. Based on laboratory testing, the neuro cybernetic prosthesis (NCP) is labelled MRI compatible when used with a send and receive head coil. However, there are no published clinical data to support the safety of brain MRI in patients with the NCP. Our objective was to report clinical experience with such a population. We questioned 40 centres that had implanted the NCP system as of 10/1/99. If MRI had been performed on any vagus nerve stimulator patients, we collected information on these patients, the MRI technique used, any events noted during the scan, including both subjective reports (by the patient ), and observable (objective) changes noted by the staff. Twelve centres (30%) responded. Over a time period of 3 years, there were a total of 27 MRI scans performed in 25 patients. All scanners were 1.5 T. A head coil was used in 26 scans, and a body coil in one. The indications for the scans were diverse. Seven were related to the epilepsy, including aetiology or pre-surgical evaluation. Others were unrelated, including brain tumours, cerebral haematoma, vasculitis, headaches, and head trauma. Three scans were performed with the stimulator on, while 24 were performed with the stimulator off. One patient had a mild objective voice change for several minutes. No other objective changes were noted in any of the patients. One 11-year old reported chest pain while experiencing severe claustrophobia. Twenty-five patients denied any discomfort around the lead or the generator. We conclude that this clinical series supports the safety of routine brain MRI using a send and receive head coil in patients implanted with the NCP System.

Severe encephalopathy associated with ifosfamide administration in two children with metastatic tumors

SummaryWe studied two children with recurrent cancer, who during treatment with ifosfamide developed severe encephalopathy characterized by coma of several days duration. Ifosfamide was used as a single drug without mesna as an uroprotector. A 1-hour infusion of ifosfamide (1.8 g/m2) was given on days one and two of a planned 5-day course. Encephalopathy was associated with severe electroencephalographic abnormalities, e.g. slowing in delta range in one patient and electrographic seizures in another. Both, clinical and electroencephalographic features of encephalopathy were reversible.

Vagus nerve stimulation for pharmacoresistant epilepsy: clinical symptoms with end of service☆

PURPOSE Limited capability exists to predict when vagus nerve stimulation (VNS) battery deterioration becomes significant. Initial models last 2-5 years. We evaluated the first 18 patients with pharmacoresistent epilepsy after reimplantation to examine the clinical course observed during VNS end of service (EOS). METHODS Of 72 patients with VNS, 18 patients had generator replacement. EOS was estimated based on duration of use and stimulus parameters in accordance with manufacturer guidelines. Eight males and ten females had pharmacoresistent epilepsy for a mean of 17.9 years. Thirteen with localization-related epilepsy (LRE) and 5 nonverbal patients with symptomatic generalized epilepsy (SGE) failed a mean of 11.1 antiepileptic drugs (AEDs) over 21.5 years. Seven had intracranial evaluations and five failed epilepsy surgery. Reimplantation was performed after a mean of 34.4 months. Symptoms at end of service (EOS) were addressed by postoperative survey submitted at initial reprogramming within 2 weeks of reimplantation. Stimulus parameters were compared before and after surgery. RESULTS Nine of thirteen (69.2%) verbal patients and 11 of 18 (61.1%) total patients had signs or symptoms prior to replacement, suggesting clinical EOS, and 4 of 18 (22.2%) failed interrogation denoting battery failure without symptoms; however, this did not reach significance (chi2=0.359,p=0.54). Increased seizures were the most frequent sign in 8 of 18 (44.4%), with intensification in 7 of 18 (38.9%). Irregular stimulation was detected in 5 of 18 (27.7%), with less intense stimulation in 4 of 18 (22.2%). Painful stimulation and behavioral worsening each occurred in 2 of 18 (11.1%). A subjective improvement in function after reimplantation was noted in 12 of 13 (92.3%) verbal patients, with greater intensity and consistency. Maximally tolerated reimplant current averaged -0.56 mA less. All but one (94.4%) felt surgery should be performed before clinical EOS occurred. CONCLUSIONS We conclude that clinical signs and symptoms may arise during VNS EOS and following replacement. Seizure increase or a change in seizure pattern was most frequently observed. The tolerated reimplant current was less than the preoperative output current in most cases. Battery replacement before EOS appears desirable from a patient perspective.

Seizures in klinefelter’s syndrome

This study describes the clinical spectrum of patients with Klinefelters syndrome and seizures. Klinefelters syndrome is a sex chromosomal abnormality and the most common cause of male hypogonadism. It is characterized by cognitive dysfunction, hypogonadism, and abnormalities of physical maturation. Neurologic impairment has been recognized, but seizures have received little attention. The authors describe three American patients and discuss nine additional patients from two European centers previously reported with Klinefelters syndrome and seizures. The most common profile of patients with Klinefelters syndrome and seizures includes mental retardation, behavior problems, epileptiform electroencephalograms (EEGs), and generalized tonic-clonic seizures. The seizures of six of 11 patients with epilepsy were well controlled with antiepileptic drugs. One patient had a single seizure and was not treated with medication. In patients with Klinefelters syndrome and recurrent seizures, the electroclinical spectrum is heterogenous and outcome with antiepileptic drug treatment is favorable.

Diffuse Axonal Injury Without Direct Head Trauma and With Delayed Onset of Coma

A 16-year-old female was involved in a jet ski (water craft) accident resulting in bilateral lower extremity fractures but no loss of consciousness or any other evidence of head trauma. Thirty hours later she became comatose. Magnetic resonance imaging was consistent with diffuse axonal injury. She recovered after several weeks without any clinical sequelae. This patient demonstrates an unusual example of diffuse axonal injury without direct head trauma and with delayed onset of symptoms. The authors recommend that patients involved in high-velocity accidents, even without immediate evidence of head injury, be observed for signs of diffuse axonal injury.

Progressive Necrotizing Myelopathy Associated With Leukemia: Clinical, Pathologic, and MRI Correlation

We describe a patient with progressive, irreversible, necrotizing myelopathy associated with myelomonocytic leukemia. The neuropathologic lesions consisted of diffuse necrosis, most pronounced in the cervical cord and affecting both the gray and white matter. These areas corresponded to areas of increased T2 on magnetic resonance imaging scans of the patient. We felt that there was no causal relationship of these lesions to any single antileukemic agent the patient received, and no other local or systemic causes were found to explain the lesions at necropsy. It is suggested that our case is an example of paraneoplastic necrotizing myelopathy. To our knowledge, this is the third case of necrotizing myelopathy associated with leukemia reported in the English medical literature, and the first one demonstrating usefulness of magnetic resonance imaging in diagnosis of necrotizing myelopathy. (J Child Neurol 1987;2:44-49).

Nerve regeneration patterns after acute ischemic injury

We performed morphologic studies on regeneration of the cats hind limb nerves, following simultaneous ligation of the aorta and right femoral artery. There were 2 regeneration patterns depending on the extent of ischemic necrosis. When nerve infarcts were limited only to intrafascicular regions, there was no basic change of nerve microarchitecture during regeneration. Extension of the necrosis to the perineurium resulted in replacement of the original fascicle by a collection of small fascicles, many of which were surrounded by their own perineurium. These mini fascicles formed within the boundaries of the old perineurium.