Gregor Herrendorf

Cisternal S100 protein and neuron-specific enolase are elevated and site-specific markers in intractable temporal lobe epilepsy.

In the brain, S100 protein and neuron-specific enolase (NSE) are mainly found in glial cells and neurons, respectively. We investigated concentrations of S100 protein and NSE in cisternal cerebrospinal fluid obtained during implantation of foramen ovale electrodes in eight patients with temporal lobe epilepsy (TLE). In addition, the meningeal markers cystatin-C and beta-trace as well as total protein were measured. Patients with trigeminal neuralgia (TN) undergoing glycerol rhizotomy served as controls. S100 protein and NSE levels ipsilateral to the site of seizure onset were significantly higher than in TN. Contralateral TLE values were also markedly but not significantly elevated. The meningeal markers cystatin-C and beta-trace protein as well as total protein did not differ in TLE and TN. We conclude that interictal temporal lobe dysfunction corresponds with neuronal and glial marker elevations in the extracellular space and that site-specific elevations may predict the site of seizure origin biochemically.

Dipole-source analysis in a realistic head model in patients with focal epilepsy.

Summary: Purpose: By the use of three different head models in EEG dipole analysis, we tried to model the origin of interictal and ictal epileptic activity as precisely as possible. Further, as a control, a second evaluation was made by an independent group to control for interindividual reliability of the dipole source analysis. With the realistic head model (CURRY) considering cortex, skull, and skin segmentation, the spike source was located.

Ictal near infrared spectroscopy in temporal lobe epilepsy: a pilot study

Near infrared spectroscopy (NIRS) is a non-invasive method to measure cerebral tissue oxygenation continuously with an adhesive optode system which can be easily placed on the skin. We coupled NIRS with video-electroencephalography (video-EEG) during the presurgical evaluation of two patients with intractable localization-related epilepsy of mesial temporal origin. Cerebral oxygen saturation was measured either ipsilaterally (three seizures) or contralaterally (four seizures) to the primary epileptogenic zone. Since NIRS measures cerebral tissue oxygenation in a depth of only few centimetres, it did not record within the primary epileptogenic zone in our patients. Therefore we decided to place the NIRS optodes comfortably for the patients on the hairless skin corresponding with measurement of the oxygenation within the corresponding frontal cortex. Ipsilateral measurement revealed a marked desaturation in the course of the seizure with a postictal maximum whereas contralateral findings were inconsistent. The favourable outcome of selective amygdalahippocampectomy in both cases retrospectively confirmed the correct lateralization by video-EEG and the concordant NIRS findings. Our preliminary results suggest that NIRS might be a simple, cost-effective and non-invasive additional method to lateralize the primary epileptogenic zone in temporal lobe epilepsy and should be further investigated in larger series of patients.

Kinetics of Serum Neuron-Specific Enolase and Prolactin in Patients After Single Epileptic Seizures

Summary: Purpose: To investigate and compare the temporal profile of serial levels of neuron‐specific enolase (NSE) and prolactin in serum from patients after single epileptic seizures.

SURFACE EMG AND MYOSONOGRAPHY IN THE DETECTION OF FASCICULATIONS : A COMPARATIVE STUDY

Surface electromyography (EMG) and muscle sonography both facilitate the detection of fasciculations. This study was conducted to evaluate the prevalence of fasciculations in 10 lower extremity muscles in 58 subjects 47 ± 18 years of age without and 54 patients 52 ± 15 years of age with various neuromuscular diseases (3 with inflammatory myopathy, 15 with lower motor neuron disease, 22 with acquired and 11 with hereditary motor and sensory neuropathy (HMSN), and 3 with adrenomyeloneuropathy). When each muscle was screened by means of myosonography for 10 seconds, fasciculations were found in up to 8 muscles in 11 control subjects (19%) and in up to 10 muscles in 41 patients (76%). Within the same recording period surface EMG revealed fasciculations in 5 control subjects (9%) and 30 patients (56%), whereas during a recording time of 20 minutes fasciculations were detected in 55 (95%) control subjects and all patients. An amplitude of 400 µV proved to be the optimum cutoff between fasciculations for healthy subjects and patients with neuromuscular disease (accuracy, 74%). Myosonography allowed differentiation of both groups with an accuracy of 79%. Surface EMG was more liable to artifacts than myosonography. The average interval between subsequent fasciculations cannot be used to differentiate patients with acquired and hereditary polyneuropathy and with lower motor neuron disease. Long‐term surface EMG recording indicates fasciculations to occur in almost all patients with neuromuscular disease and the vast majority of healthy subjects. Muscle ultrasonography was more convenient and reliable than surface EMG in differentiating patients and healthy subjects.

The Lateralizing Value of Ictal Clinical Symptoms in Uniregional Temporal Lobe Epilepsy

In order to assess the lateralizing value of several ictal and postictal clinical symptoms in temporal lobe epilepsy (TLE), we analyzed 89 seizures of 20 left dominant patients with intractable left (n = 9) versus right (n = 11) TLE who had undergone successful anterior temporal lobectomy. In left TLE, movement arrest at seizure onset, postictal dysphasia >120 s and postictal dyslexia >180 s were the most typical findings and associated with a sensitivity of 94, 94, and 100%, respectively. The highest specificity of 100% each was evident for contralateral versions of eyes and head and dystonic posturing. In right TLE, the highest sensitivity was seen for whole-body movements at seizure onset, postictal dysphasia <120 s and postictal dyslexia <180 s with figures of 82, 87, and 93%, respectively. As compared to left TLE, contralateral version and dystonic posturing, ictal speech, and postictal dyslexia <180 s each had a specificity of 100%. The careful combined analysis of certain ictal clinical signs combined with consistent findings of interictal EEG and neuroimaging studies may be often sufficient to proceed with epilepsy surgery without invasive recordings even if ictal scalp EEG is not unambiguous.

Isolated ataxia as an idiosyncratic side-effect under gabapentin

Gabapentin has been accepted worldwide as a novel antiepileptic drug with a favourable tolerability profile. However, movement disorders have been reported previously as rare side-effects in individual patients. We report on two patients who developed isolated severe ataxia under low-dose gabapentin which resolved abruptly after discontinuation of the drug. This side-effect probably resembled a rare idiosyncratic adverse reaction. We propose the gabapentin-specific neuronal binding site which has a high density in the cerebellum as a possible mechanism of action and suggest that the initiation of gabapentin requires caution if pre-existing cerebellar function impairment is evident.

Blood flow velocities in middle cerebral artery branches after subarachnoid hemorrhage.

In a prospective study, 55 patients were examined by transcranial duplex sonography (TCCS) after subarachnoid hemorrhage (SAH) to determine whether additional transcranial duplex examination on the middle cerebral artery M2 segments would aid in the examination of the MCA stem segment. The mean blood flow velocities and pulsatility index were correlated to the occurrence of delayed ischemic neurologic deficits (DIND). Out of 47 patients included, 21 did not experience any delayed deficit (group 1), 15 did (group II), and in 11 the extent to which vasospasm contributed to a neurologic deficit was unclear (group III). The highest blood flow velocity and the greatest increase of mean blood flow velocity on 1 day were significantly higher in groups II and III both in M1 and in M2. In 10 patients in group II, where the onset day of DIND was known exactly, Doppler data indicating ischemia before or at the time of DIND were observed in nine. In eight patients, Doppler of the MCA stem alone would have provided enough information to recognize the risk of symptomatic vasospasm; in one patient, only the M2 Doppler gave an indication of ischemic complication. Transcranial duplex sonography may provide additional information to TCD by accurate delineation of M1/M2 vasospasm and therefore may help plan cerebral angiography and neurointerventional treatment.

Transitory Fourth Cranial Nerve Palsy due to Foramen Ovale Electrode Placement

We report on a 56 year old female patient with a drug-resistant localization-related epilepsy with complex-partial and secondary generalized seizures of unknown aetiology. Video-EEG-monitoring with scalp-electrodes bad not been sufficient to determine the primary epileptogenic zone, so that we decided to perform a second EEG-monitoring phase with scalp electrodes and additional FOE. Flexible 4-contact FOE (AD-Tech Medical Instrument Corporation, Racine, WI, U.S.A.) with a diameter of 1 mm were placed through the foramen ovale bilaterally using a 17 gauge introducing needle. For local anaesthesia bupivacain 0.5% was given. The implantation technique has been described in detail by Wieser [3, 4]. Under x-ray control, bilateral implantations were performed without complications. The implantation time was five minutes on the left and 13 minutes on the right side, the latter due to several positioning adjustments prior to the placement in loco typico (Fig. 1). After dural penetration on the left side, a considerable loss of cerebrospinal fluid was observed the amount of which could not be measured precisely. Oral amoxicilline, which we use prophylactically, was started on the implantation day and continued until one day after explantation. Continuous monitoring was performed for 5 days. The FOE were explanted immediately after the end of the monitoring without complications. A few hours after implantation correlating with the diminishing effect of local anaesthesia the patient complained of moderate pain in both cheeks increased by chewing. This side-effect is not unusual [4] and disappeared after a few days. One day after the implantation the patient complained about blurred vision. In a first orientating physical examination we found a palsy of the left N. trochlearis persisting after explantation of the FOE. A neuro-ophthalmological examination confirmed our diagnosis of a palsy of the left N. trochlearis. A computer-tomography immediately afte r explantation and magnetic resonance imaging with additional sequences of the brain stem six days after explantation showed no morphological abnormality. In the course of the following days, the patient reported gradual improvement. Sixty-seven days after explantation of the FOE all pre-existing subjective symptoms were no longer present. The physical examination confirmed normal findings.

An easy method to accelerate ictal SPECT.

An Easy Method to Accelerate ldal SPECT Interictal and ictal single-photon emission computed tomography (SPECT) is useful for the localization of the primary epileptogenic zone in patients with pharmacoresistant focal epilepsy. In mesial-temporal epileptogenesis injection of 99m Tc-Ethyl cysteinate dimer (ECD) less than 30 seconds after clinical seizure onset usually leads to a regional hyperperfusion in the ipsilateral mesial-temporal region/ whereas interictal injection shows a hypoperfusion in this region? In extratemporal epileptogenesis, it seems to be crucial to reduce this interval considerably to prevent unspecific propagational effects, especially in cases with short seizure duration? Therefore, we developed an easy method to accelerate the ictal injection of the tracer. In addition, this approach will reduce the radioactive contamination of the investigators. In our video EEG unit, the patients and the BEG-monitoring staff are located in two separate rooms. The shortest time in our previous ictai-SPECT studies between seizure onset and bedside injection was 13 seconds with a mean of 20 seconds. In the last two patients, we used our new method: an IV cannula (18G 13/4) was connected with an extending tubing for infusion lines (length 3 m) to a 3-way stopcock manifold onto a PerfusorSyringe (Brawn, Melsungen, Germany) with 50 ml injectible water. The 50 ml Perfusor Syringe was placed in a metal box with a lead shielding. The syringe with the ECD-Tracer was connected to the 3-way stopcock manifold near the Perfusor Syringe (Fig 1). We used 2.0 ml of 15 mCi Tc-99m-Neurolite Tracer. The tracer was injected into the tube (the extending tube contains 4 ml) and immedi-