Ecosystem service valuation method through grey water footprint in partially-monitored subtropical watersheds.

The valuation of ecosystem services of pollution regulation in basins with partial monitoring does not have only one consolidated methodology which can be applied in all countries, biomes and across spatio-temporal scales. While different metrics can incorporate elements of uncertainty for decision makers, changes in land use, climate and sectoral demands in basins increase the need for the efficiency and complexity of valuation methods. Here, based on adapting a pre-existing method, we present a new ecosystem service valuation applied to river basins under different characteristics in the biomes of the Atlantic Forest and Brazilian savannah. Our assumptions of ecosystem service valuation concern an analogy based on willingness-to-pay for not marketable services, but adapted by data from the river basins' ecohydrological monitoring. First, the method depicts river ecosystem valuation with probabilistic criteria of both the water yield, as supply, and the grey Water Footprint (greyWF), as demand. Second, we introduced the comparison between water supply and demand carried out on the continuous flow regime and monitored loads in rivers with different land uses, sizes and biomes. Third, this new ecosystem service valuation method enabled us to quickly visualize the possible stages of sustainability concerning the Brazilian legal framework among different basins. The methodology was applied in 12 Brazilian river basins, with drainage areas between 17 and 26,500 km2, and changes in land use with variable percentages of urban (62-92%), forest (51-84%) and agriculture (51-89%) areas. The most polluted basins, with greyWF values far above those allowed, have the most significant, almost asymptotic valuation curves. Results range from a minimum reference value of 61 US$/ha/year for conservation, adapted from the Brazilian Water Producer, to US$ 330 for restoring high polluted basins. The results show the viability of this method and discuss further opportunities for water security, especially for climate change and non-stationary sectorial demands.

Cryopreserved porcine tendons preserve cell viability after thawing.

Controlled cryopreservation is an important method for storage of tissue grafts in skin banking, reproductive medicine and other domains. Although the availability of cryopreserved flexor tendons would be highly beneficial in reconstructive surgery, especially in complex reconstructions for which grafting material is limited, only a few studies have dealt with transplanted tendons. We achieved successful cryopreservation of porcine flexor tendons in 2 cryoprotective media: dimethyl sulfoxide and glycerol. Their viability was shown using a quantitative colorimetric MTT (3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide) assay. For comparison of native and cryopreserved tendons (n = 7 samples each), the adopted viability index was the ratio of MTT-dependent optical density and tendon weight. The viability index of native samples did not change significantly after cryopreservation and thawing. The proliferative capacity of tendon fibroblasts after thawing was shown in primary cell cultures. The described cryopreservation protocol and MTT assay may provide a basis for future autografting of human tendons.

Control of symptoms in patients with Meniere's disease using middle ear pressure applications: two years follow-up.

The effects of middle ear pressure pulses were studied in 37 patients with a diagnosis of definite Meniere's disease and active vestibular symptoms, 31 of whom had failed to respond to medical treatment including diuretics prior to pressure treatment. The number of vertigo spells during the 6 months prior to treatment and for 6, 18 and 24 months after the start of treatment were evaluated. The functionality level scores were three or worse according to the American Academy of Otolaryngology--Head and Neck Surgery (AAO-HNS) criteria. The results of the study were as follows: 19 patients experienced freedom from vertigo spells; 15 patients reported a significant decrease in the frequency of vertigo spells; and 3 patients did not respond to pressure treatment and were subjected to gentamicin injections, I of whom consequently became deaf in the affected ear. No patient became worse in connection with pressure treatment. With the exception of the three patients who did not respond to pressure treatment, all patients reported an improvement in functionality of at least two levels according to the AAO-HNS functionality scale. No side effects or adverse events were observed during the 2 years of pressure treatment. Overall, the results indicate that pressure treatment provides efficient control of symptoms in patients with intractable forms of Ménière's disease without producing any adverse effects on the inner ear.

N-Cadherin extracellular repeat 4 mediates epithelial to mesenchymal transition and increased motility.

E- and N-cadherin are members of the classical cadherin family of proteins. E-cadherin plays an important role in maintaining the normal phenotype of epithelial cells. Previous studies from our laboratory and other laboratories have shown that inappropriate expression of N-cadherin by tumor cells derived from epithelial tissue results in conversion of the cell to a more fibroblast-like cell, with increased motility and invasion. Our present study was designed to determine which domains of N-cadherin make it different from E-cadherin, with respect to altering cellular behavior, such as which domains are responsible for the epithelial to mesenchymal transition and increased cell motility and invasion. To address this question, we constructed chimeric cadherins comprised of selected domains of E- and N-cadherin. The chimeras were transfected into epithelial cells to determine their effect on cell morphology and cellular behavior. We found that a 69-amino acid portion of EC-4 of N-cadherin was necessary and sufficient to promote both an epithelial to mesenchymal transition in squamous epithelial cells and increased cell motility. Here, we show that different cadherin family members promote different cellular behaviors. In addition, we identify a novel activity that can be ascribed to the extracellular domain of N-cadherin.

Temporal lobectomy in children: cognitive outcome.

OBJECT: The authors sought to determine the impact of early temporal lobectomy (in patients younger than age 17 years) on intellectual functioning. The efficacy of temporal lobectomy for treating seizures is well established and the procedure is becoming more acceptable as a treatment for children whose seizures are intractable. However, cognitive outcomes of temporal lobectomy in children and adolescents are largely unreported. The present study takes advantage of a unique multicenter collaboration to examine retrospectively intellectual functioning in a large sample of children who underwent temporal lobectomy. METHODS: Intellectual functioning was assessed before and after temporal lobectomy for treatment of medication-resistant seizures in 82 patients at eight centers of epilepsy surgery. All children underwent standard presurgical examinations, including electroencephalography-video monitoring, magnetic resonance (MR) imaging, and neuropsychological testing, at their respective centers. Forty-three children underwent left temporal lobectomy and 39 underwent right temporal lobectomy. For the entire sample, there were no significant declines in intelligence quotient (IQ) following surgery. Children who underwent left temporal lobectomy demonstrated no significant loss in verbal intellectual functioning and improved significantly in nonverbal intellectual functioning. Children who underwent right temporal lobectomy did not demonstrate significant changes in intellectual functioning. Although group scores showed no change in overall IQ values, an analysis of individual changes revealed that approximately 10% of the sample experienced a significant decline and 9% experienced significant improvement in verbal functioning. Significant improvement in nonverbal cognitive function was observed in 16% of the sample and only 2% of the sample showed significant declines. Risk factors for significant decline included older patient age at the time of surgery and the presence of a structural lesion other than mesial temporal sclerosis on MR imaging. CONCLUSIONS: The present study provides preliminary data for establishing the risk of cognitive morbidity posed by temporal lobectomy performed during childhood. With respect to global intellectual functioning, a slight improvement was significantly more likely to occur than a decline. However, there were several patients in whom significant declines did occur. It will be necessary to study further the factors associated with such declines. In addition, further study of more specific cognitive functions, particularly memory, is needed.

Electrocochleographic signal analysis: condensation and rarefaction click stimulation contributes to diagnosis in Menière's disorder.

Thirty patients with Menière's disorder, 11 patients with cochlear hearing loss of other aetiologies and 10 normally-hearing subjects, were investigated using transtympanic electrocochleography (TT ECochG). Alternating polarity clicks, condensation and rarefaction clicks and long tone-bursts of 1 kHz were used for stimulation. The latencies of the AP responses to click stimulation were evaluated. It was found that the latency differences between the condensation and rarefaction click-evoked responses were significantly larger in patients with Menière's disorder as compared to normal subjects and to patients with other cochlear hearing losses. It was found that the sensitivity of TT ECochG, obtained by using measurements of SP-AP ratios and the SP amplitude at 1 kHz burst stimulation, increased from 83 per cent to 87 per cent by addition of the con-rar shift measurement. The specificity of TT ECochG obtained by this combination of variables was 100 per cent in our material. The results of the study indicate that the latency shift found in responses evoked by clicks of opposite polarities in TT ECochG, can be a useful parameter in the detection of suspected endolymphatic hydrops.

Sensitivity and specificity of transtympanic electrocochleography in Meniere's disease.

Transtympanic electrocochleography (TT ECoG) was conducted in 61 patients (61 ears) with the clinical diagnosis of Meniere's disease and 15 patients (21 ears) with cochlear hearing loss of other aetiologies to assess the ability of the method to separate different cochlear disorders. The click-evoked summation potential/action potential (SP/AP) ratio and the 1 and 2 kHz burst-evoked SP amplitudes were evaluated. Based on the TT ECoG results from 13 normal hearing subjects (15 ears) the upper limit of each variable was determined, above which a value was considered pathological, i.e. indicative of endolymphatic hydrops. The results showed that the sensitivity of the SP/AP ratio was 62% and specificity 95%. When evaluating the combinations of TT ECoG parameters with logistic regression, SP/AP ratio and 1 kHz burst-evoked SP amplitude were shown to increase the discriminating ability of TT ECoG significantly. Inclusion of the 1 kHz burst-evoked SP amplitudes increased sensitivity to 82%, without changing specificity. Inclusion of the 2 kHz burst had no effect on sensitivity or specificity.

Recording techniques for transtympanic electrocochleography in clinical practice.

Enhancement of the signal-to-noise ratio is a central issue in electrically evoked response techniques. Transtympanic electrocochleography requires careful methodological considerations as responses from the cochlea may easily be affected by various sources of electromagnetic noise. The final electrophysiological waveforms are acquired by advanced signal processing which influences the content of the recordings. A standard method of transtympanic electrocohleography is presented here to increase the feasibility of the measurements in daily clinical use and to facilitate uniform interpretation of the recordings. The electrocochleographic recordings were carried out in 61 patients with a clinical diagnosis of Meniere's disease and in 15 ears of normal hearing subjects. The electrophysiological data are presented and set in relation to the results reported by other laboratories under equivalent recording conditions. Methodological factors of consequence for the quality of the recordings, such as testing environment, properties of the equipment, mode to produce and deliver stimuli and properties of the electrodes, are analysed.

Transtympanic electrocochleography in the assessment of perilymphatic fistulas.

An objective method for the pre-operative diagnosis and the post-operative assessment of a presumed perilymphatic fistula (PLF) using transtympanic electrocochleography is presented. Three cases are reported in which the history of the disease and the symptoms strongly suggested the presence of a PLF. Pre-operative transtympanic electrocochleography (TT ECoG) recordings at rest showed changes similar to those of endolymphatic hydrops and signs of instability of the inner ear hydrodynamic system during raised intrathoracic pressure. Surgery revealed a visible leak in two of the three cases. Both windows were repaired in all the patients. All patients were relieved from their vestibular symptoms at the time when the post-operative TT ECoG was conducted 3-6 months later. The post-operative recordings were stable during raised intrathoracic pressure and the previously elevated summating potentials decreased which was interpreted as an objective indication of the recovery of the hydrodynamic system. However, later one of the patients again developed recurrent vertigo. Twenty patients with well-documented Ménière's disease were used as a control group. TT ECoG was conducted during raised intrathoracic pressure. The Ménière patients showed stable recordings. It is suggested that among patients with suspected PLF and signs of hydrops in TT ECoG, a dependence on the intrathoracic pressure reflected in the recordings may indicate a possible fistula.

Immediate effects of middle ear pressure changes on the electrocochleographic recordings in patients with Menière's disease: a clinical placebo-controlled study.

OBJECTIVE: The aim of the study was to evaluate effects of middle ear pressure changes on the electrocochleographic responses in patients with well-defined Menière's disease. STUDY DESIGN AND INTERVENTIONS: The investigation was conducted as a placebo-controlled, randomized clinical study. Electrocochleographic measurements were performed before and after the insertion of a transtympanic ventilation tube and immediately after the exposure to active or placebo treatment. SETTING: The study was carried out in one secondary referral center and one tertiary referral center on an ambulatory basis. PATIENTS: Thirty-nine patients with well-defined Menière's disease were included in the study. MAIN OUTCOME MEASURES: The summating potential/action potential ratio of the electrocochleographic response complex was chosen as the main variable for statistical evaluation of results. Other parameters of the recordings such as responses to low-frequency burst stimulation also were evaluated. Subjective symptoms (e.g., vertigo, tinnitus, and aural pressure) were assessed before and after insertion of the ventilation tube and before and after exposure to treatment. RESULTS: A statistical difference was shown in the electrocochleographic response in the active group before and after exposure to middle ear pressure changes. In the placebo group, no change was found. Changes in electrocochleographic parameters in the active group indicated an improvement in inner ear electrophysiology. No significant changes were found in subjective symptoms in the active or the placebo group. Evaluation before and after insertion of the ventilation tube showed no significant improvement in any variable. CONCLUSIONS: This is the first study in which electrophysiologic parameters were evaluated in a placebo-controlled clinical trial of overpressure treatment in Menière's disease. The results show that electrophysiologic parameters can be improved by the application of positive pressure pulses of low amplitude in the middle ear.

Clinical and laboratory evaluation of a closed enteral feeding system under cyclic feeding conditions: a microbial and cost evaluation.

Cyclic feeding schedules are now commonly used in conjunction with closed enteral feeding systems. Some manufacturers and clinicians have speculated that closed system cyclic feeding may promote formula contamination via retrograde movement of bacteria during the "no-flow" periods. Using both laboratory and clinical settings, our study evaluated whether retrograde bacterial movement under "no-flow" conditions results in contamination of closed system feeding containers. The clinical phase was conducted with 57 closed system feeding containers used to feed nursing home residents. In both laboratory and clinical testing there was no evidence of container contamination at 36-48 h, nor was there evidence of retrograde movement of bacteria beyond the drip chamber. Formula waste and costs were also analyzed using several 24- or 36-h hang time scenarios. Provided the appropriate container size is used, potential cost savings between $67 to $135 per patient per month may be achieved with the 36-h hang time scenarios. Retrograde movement of bacteria does not appear to be a source of closed system feeding container contamination in systems that incorporate a drip chamber. Using the appropriate size feeding container and systems with at least a 36-h hang time will result in significant cost savings.

Effects of electrically induced fatigue on the twitch and tetanus of paralyzed soleus muscle in humans.

We analyzed the twitch and summated torque (tetanus) during repetitive activation and recovery of the human soleus muscle in individuals with spinal cord injury. Thirteen individuals with complete paralysis (9 chronic, 4 acute) had the tibial nerve activated every 1,500 ms with a 20-Hz train (7 stimuli) for 300 ms and a single pulse at 1,100 ms. The stimulation protocol lasted 3 min and included 120 twitches and 120 tetani. Minimal changes were found for the acute group. The chronic group showed a significant reduction in the torque and a significant slowing of the contractile speeds of both the twitch and tetanus. The decrease in the peak twitch torque was significantly greater than the decrease in the peak tetanus torque early during the fatigue protocol for the chronic group. The twitch time to peak and half relaxation time were prolonged during fatigue, which was associated with improved fusion of the tetanus torque. At the end of the fatigue protocol, the decrease in the peak twitch torque was not significantly different from the decrease in the peak tetanus torque. After 5 min of rest, the contractile speeds recovered causing the tetanus to become unfused, but the tetanus torque became less depressed than the twitch torque. The differential responses for the twitch and the tetanus suggest an interplay between optimal fusion created from contractile speed slowing and excitation contraction coupling compromise. These issues make the optimal design of functional electrical stimulation systems a formidable task.

Cross-talk between adherens junctions and desmosomes depends on plakoglobin.

Squamous epithelial cells have both adherens junctions and desmosomes. The ability of these cells to organize the desmosomal proteins into a functional structure depends upon their ability first to organize an adherens junction. Since the adherens junction and the desmosome are separate structures with different molecular make up, it is not immediately obvious why formation of an adherens junction is a prerequisite for the formation of a desmosome. The adherens junction is composed of a transmembrane classical cadherin (E-cadherin and/or P-cadherin in squamous epithelial cells) linked to either beta-catenin or plakoglobin, which is linked to alpha-catenin, which is linked to the actin cytoskeleton. The desmosome is composed of transmembrane proteins of the broad cadherin family (desmogleins and desmocollins) that are linked to the intermediate filament cytoskeleton, presumably through plakoglobin and desmoplakin. To begin to study the role of adherens junctions in the assembly of desmosomes, we produced an epithelial cell line that does not express classical cadherins and hence is unable to organize desmosomes, even though it retains the requisite desmosomal components. Transfection of E-cadherin and/or P-cadherin into this cell line did not restore the ability to organize desmosomes; however, overexpression of plakoglobin, along with E-cadherin, did permit desmosome organization. These data suggest that plakoglobin, which is the only known common component to both adherens junctions and desmosomes, must be linked to E-cadherin in the adherens junction before the cell can begin to assemble desmosomal components at regions of cell-cell contact. Although adherens junctions can form in the absence of plakoglobin, making use only of beta-catenin, such junctions cannot support the formation of desmosomes. Thus, we speculate that plakoglobin plays a signaling role in desmosome organization.

Radiotracer binding to brain microsomes determined by thin-layer chromatography.

A thin-layer chromatography (TLC) assay was developed to monitor the interaction of radiotracers with brain microsomes. Murine brain microsomes were coated onto a zone of a TLC strip, the unreacted sites blocked with gelatin, and the radiotracers chromatographed over the microsomes. Radiotracers bound to the microsomes and were separated from the unreacted materials which migrated at or near the solvent front. Up to 80% of the applied radioactivity bound to the brain microsomes when using 99mTc-(d,l) hexamethyl-propyleneamine oxime (HMPAO) and 123I-(S)-2-hydroxy-3-iodo-6-methoxy-N-[(1-ethyl-2-pyrrolidinyl) methyl]-benzamide (123I-IBZM) as tracers. On the other hand, the presumptive negative control materials p-I-15-phenyl-pentadecanoic acid-123I (123I-IPPA) and 99mTc-mercapto-acetyl triglycine (MAG3) bound poorly (7% and 4%, respectively). 99mTc-ethyl cysteinate dimer (ECD) interacted poorly (9.9%), a result thought to be consistent with its known inability to be metabolized by nonprimate brain tissue. Radiolabeled octreotide analogues (radiolabeled with 111In, I-131 or 99mTc) also bound, and the binding could be reduced by excess unlabeled octreotide. Also, chemical modification by acylation of Lys5 in 111In-labeled octreotide led to decreased binding (approximately 70%) compared to the original radiotracer. Chromatography of the various radiotracers over TLC strips coated only with gelatin was used to monitor nonspecific binding and was low and frequently below 5%. This technique does not require wash steps or centrifugation, and assays are rapidly completed. The assay could be useful in monitoring the interaction of radiotracers with brain microsomes and in evaluating and developing new radiotracers.

Verbal memory impairment resulting from hippocampal neuron loss among epileptic patients with structural lesions.

We recently demonstrated statistically significant correlations between presurgical memory impairment and hippocampal volumetric cell densities (in CA3 and the hilar area only) for patients with idiopathic left temporal lobe epilepsy who exhibited marked hippocampal neuron loss. In the present research we determine whether the same relationship exists for patients with structural lesions, in whom hippocampal neuron loss was minimal. Rank-order correlations of verbal memory test results (ie, Long Term Retrieval score of the verbal Selective Reminding Test, Percent Retention index of the Logical Memory subtest of the Wechsler Memory Scale) and hippocampal volumetric cell densities (subfields CA1, CA2, CA3, the hilar area, and the granule layer of area dentata) were computed for 22 patients with structural lesions and medically refractory epilepsy of temporal lobe onset (11 left, 11 right). There were statistically significant correlations between Long Term Retrieval and the volumetric cell density of CA1 (r = 0.62, p < 0.05) and between percent retention and the volumetric cell density of CA2 (r = 0.60, p < 0.05) for patients with left hemisphere lesions. No other correlations were found for patients with left or right temporal lobe lesions.

Short term effects of induced middle ear pressure changes on the electrocochleogram in Menière's disease.

Electrocochleographic recordings were made in 17 patients with Menièr's disease before and immediately after exposure to pressure applications in their middle ear. The variables of the response to clicks such as the SP/AP ratio and the width of the complex as well as the amplitudes of the SP in response to long tone bursts were evaluated. Improvement of electrocochleographic recordings, characterized by normalization of the waveforms and reduction of the SP, was found to be significant. The results indicate a mechanoelectric change in the hydroptic cochlea registered directly after exposure to middle ear pressure changes.

Right hemisphere mediation of verbal learning and memory in acquired right hemisphere speech dominant patients.

Forty-eight patients with temporal lobe epilepsy completed measures of narrative recall and list learning prior to surgery. The intracarotid amytal procedure (IAP) established that 13 patients were right hemisphere dominant for speech and 35 (18 left foci, 17 right foci) were left hemisphere dominant. Hippocampal volumetric neuron densities were measured after surgery. The left hippocampal neuron densities in subfields CA3 and the hilar area were significantly correlated with list learning ability and percent retention for narrative recall only for left hemisphere speech dominant patients with left seizure foci. No significant correlations between measures of neuron volume and memory were found for the left hemisphere speech dominant patients with right seizure foci or the right hemisphere speech dominant patients with left seizure foci. This suggests that the right hemisphere of right speech dominant patients mediates verbal memory as well as speech. This conclusion is supported by patterns of correlations among measures of verbal memory that differed for patients undergoing resection of the dominant hemisphere versus those undergoing resection of the nondominant hemisphere. However, it is premature to conclude that the cerebral organization of cognitive functions of right hemisphere speech dominant patients is equivalent albeit reversed from that of left hemisphere speech dominant patients. Right hemisphere speech dominant patients with left temporal foci differed from left hemisphere speech dominant patients with right temporal foci with respect to the patterns of correlations between measures of verbal memory and intelligence as well as the level of intellectual ability that they demonstrated.

Wada memory disparities predict seizure laterality and postoperative seizure control.

We examined the efficacy of a memory difference score (DS: right minus left hemisphere memory) during the Wada test (intracarotid amobarbital procedure, IAP) for predicting seizure laterality and postoperative seizure outcome in 70 left speech dominant patients from two epilepsy centers. DS > or = 2, after addition of 1 point to the left hemisphere injection score to account for aphasia, were noted in 71.4% of patients and correctly predicted surgery side for 98.0% of these patients. The DS related significantly to seizure outcome at 1-year follow-up (p < 0.002) and correctly predicted 80% of patients who were seizure-free. Patients whose DS did not correctly predict seizure laterality more frequently required invasive studies to establish seizure onset. The relationship of the DS to laterality did not differ significantly by class of IAP memory stimuli. When seizures originate from the temporal lobe, the IAP memory DS predicts seizure laterality by assessing the functional adequacy of the involved hemisphere and is predictive of seizure control.

General cognitive ability following unilateral and bilateral fetal ventral mesencephalic tissue transplantation for treatment of Parkinson's disease.

OBJECTIVE: To contrast the neuropsychological profiles of Parkinsonian patients, before and after fetal ventral mesencephalic tissue transplantation. DESIGN: Case series of personally examined patients. SETTING: Patients were evaluated by neurologists, neurosurgeons, and neuropsychologists as outpatients at a university hospital. PATIENTS: Fetal mesencephalic tissue was implanted in the right caudate nucleus of three patients and both nuclei of one patient. These patients were evaluated prior to surgery and at 12, 24, and 26 months postoperatively. RESULTS: Factor analysis of the test battery identified four statistically orthogonal test clusters. No statistically significant changes were identified postoperatively for clusters assessing verbal cognitive ability, nonverbal cognitive ability, and information-processing speed. An improvement of verbal memory cluster index was observed 12 months after surgery, and the improvement reached the level of statistical significance at 24 months after surgery. However, the verbal memory of all patients declined between 24 and 36 months after surgery. CONCLUSIONS: Fetal tissue transplantation to one or both caudate nuclei did not permanently arrest cognitive dysfunction. Although there is some evidence of improved cognitive ability after transplantation, it is improbable that normal cognitive function can be restored by this procedure because the impairments of cognitive ability associated with Parkinson's disease do not appear to originate solely from dopamine deficiency.

Successful epilepsy surgery without intracranial EEG recording: criteria for patient selection.

Twenty-two patients with intractable complex partial seizures (CPS) were treated with temporal lobectomy. Eighteen of 22 (82%) are seizure-free while receiving medication, with a mean follow-up time of 4 years. In each case, the clinical seizure pattern, interictal and ictal scalp EEG, magnetic resonance imaging (MRI), neuropsychological testing, and results of the intracarotid amobarbital procedure (IAP) converged to indicate a localized abnormality. None of the patients in this series had mass lesions, vascular malformations, or cortical scars, but 18 of 22 had hippocampal atrophy on MRI and 20 had hippocampal sclerosis (HS) on pathologic examination. We believe it is possible, on the basis of the preoperative evaluation described, to identify a population of epileptic patients who will do very well postoperatively. Such patients do not require invasive EEG monitoring, and they represent approximately 20% of the patients treated surgically in our epilepsy unit in the past several years.