(CT) and an audiometric assessment. All these are needed to deter-mine if surgery is recommended for the patient.

Case report: A 6-year-old male with atresia of the left EAC.BAER study showed a left conductive hearing loss. No alterations

were found on the right side.Conclusion: A third of the subjects with EACA are not candidates

for surgical correction. Proper selection of the patients for surgicaltreatment maximizes the opportunity for hearing recovery and min-imizes the possible surgical complications such as lesion of the facialnerve. In most cases, the radiological findings in the middle eardetermine the surgical indication. In uncooperative patients and inchildren, BAERs are useful to detect the involvement of other struc-tures of the auditory pathway. Determining the level of cochlearfunction in each ear is crucial in these patients in order to preventoperating on an ear with little potential for hearing improvement.

doi:10.1016/j.clinph.2008.09.035

8. Preoperative Magneto encephalography (magnetic sourceimaging) and intraoperative stimulation cortical mapping cor-relation—M. González-Hidalgo 1, C.J. Saldaña Galan 2, F. Maeztu 3,C. Amo 1, A. Fernández 1, T. Ortiz 3, C. Franco Carcedo 1, P. MataGonzález 1 (1 Neurophysiology, Complutense University, Madrid,Spain, 2 Neurosurgery, Complutense University, Madrid, Spain,3 Magnetoencephalography Center, Complutense University,Madrid, Spain)

Introduction: The management of lesions involving eloquentcortex entails significant functional risk. Presurgical localization ofthese functional areas can aid in planning the therapeutic optionsand surgical approaches. Magneto encephalography is a non-inva-sive technique that provides preoperative functional location of mo-tor, somatosensory and language cortical areas and epileptic activityrelated to anatomical landmarks.

Objective: To validate presurgical functional information obtainedfrom 7 magnetic sources imaging in patients operated while awakewith realization of intraoperative cortical stimulation mapping.

Patients and methods: Six patients (Mean age: 44 years, ranges:9–70; 2 females and 4 males) with intra axial cerebral lesions locatedclose to eloquent brain cortex were studied preoperatively andunderwent magnetic source imaging techniques. MEG data were col-lected using a 148-channels Magnes 500WH biomagnetometer. Thepatients then underwent craniotomy while awake and direct corticalelectrical stimulation, mapping areas related to motor, somatosen-sory and language functions. The accuracy of presurgical studieswas assessed by gross visual comparison and by the integration ofMEG data into a neuronavigational system.

Results and conclusions: MEG data show reasonably good con-cordance with epileptic activity, somatosensory and language intra-operative mapping, letting us achieve anatomo-functionalpresurgical planning that must be validated by intraoperative corti-cal stimulation.

doi:10.1016/j.clinph.2008.09.036

9. Neurophysiological findings in Lafora disease: A detailed studyof a patient—S. Pérez, M.Gratacos, N. Raguer, l. Pericot, A. Ferré,T. Minoves (Clinical Neurophysiology and Neurology Depart-ments, Vall Hebron Hospital, Barcelona, Spain)

Obiective: To report on the neurophysiological findings of apatient with the typical clinical and paraclinical features of Lafora’sdisease.

Patient and methods: Electroencephalogram, somatosensory, vi-sual and brainstem evoked potentials, electromyography and trans-cranial magnetic stimulation (TMS) were performed on a 50-year-old woman presenting progressive spastic paraparesia and bladderdysfunction. Muscle biopsy was consistent with Lafora disease. Rou-tine laboratory determinations, cranial and medullar MRI and oph-thalmologic studies were normal.

Results: The EEG showed deterioration of the background activ-ity and occipital bilateral spikes. Visual-Evoked Potentials and Brain-stem-Evoked Potentials were normal. However, Somatosensory-Evoked Potentials showed an increased central conduction time withhigh amplitude responses. Transcranial magnetic stimulation elic-ited abnormal cortical responses from upper and lower extremities.

Conclusion: Giant evoked potentials, generalized epileptiformdischarges and occipital spikes are common findings in Lafora dis-ease that can help us in identifying asymptomatic patients or thosepresenting unspecific symptomathology.

doi:10.1016/j.clinph.2008.09.037

10. Analysis of the responses in the Recovery Cycle of the BlinkReflex (RCR)—A. Polo, A. Esteban, A. Traba, J. Prieto, A.B. Blanco,B. Godes (Dept. of Clinical Neurophysiology, Hospital Universi-tario G, Marañón, Madrid, Spain)

Background and objective: RCR results published in the litera-ture show a great variability probably due to different criteria andmethods used.

Patients and methods: Six normal RC and 35 facilitated RC werestudied. A paradigm of the same intensity paired stimulation wasused, with inter-stimuli intervals (ISIs) of 100, 300, 500, 1000 and1500 ms. The recovery of rectified and averaged R response was calcu-lated in 4 ways: total area, inc1uding 40 and 50 ms windows (A W40and A W50) from the start of response and maximum amplitude.

Results: Significant differences between both groups (p < 0.00l)were found in the area for ISIs of 100, 300 and 500 ms, but not forISI of 1000 and 1500 ms. The amplitude showed a great variability.

Correlation among the four methods was greater for total areaand A W40 values. Recovery mean values for ‘‘A W 40 were 0.54(ISI 100), 3.4 (ISI 300) and 46.9 (ISI 500). In the facilitated groupthe mean va1ues were 38.5 (ISI 100), 71.9 (ISI 300) and 80.1 (ISI500). The frequency of response was remarkably different: 1/ 6 innormal and 34/35 in facilitated group for ISI 100; 5/ 6 and 35/35,respectively, for ISI 300 and 100% in both groups for the rest of ISIs.

Conclusion: A W40 method shows a high correlation with totalarea analysis and it is of easy application.

doi:10.1016/j.clinph.2008.09.038

11. Cranial nerves stimulation in the posterior fossa with Trans-cranial Magnetic Stimulation (TMS)—A. Esteban, A. Traba, J. Pri-eto (Department of Clinical Neurophysiology, HospitalUniversitario G, Marañón, Madrid, Spain)

Background and objectives: Cranial nerve evaluation with TMSis usually performed only in the facial nerve. Data obtained fromthe accessory and hypoglossal nerves using TMS are described.

Method: TMS over posterior fossa was applied on both sides in 6normal subjects. Short diameter, eight-shaped coil was employed.Responses were recorded with cutaneous electrodes in the trapeziusmuscle for the accessory nerve and enoral electrodes over the tonguefor the hypoglossal nerve.

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Results: Compound muscle action potentials (CMAPs) wereobtained systematically in both territories with the coil placed overthe inion-mastoid line, 6–7 cm away from the inion. Mean values oftrapezius CMAP were 4.1 ms of latency and 113 mV of amplitude.Tongue CMAP values were of 4.1 ms of latency and 6.6 mV ampli-tude. Latencies were not modified neither coil displacement throughthe inion-mastoid line nor with the increment of the stimulus inten-sity. CMAPs obtained with electrical stimulation of the most proxi-mal peripheral segments of the nerves showed values of 3 ms and11.4 mV in the trapezius muscle and .3 ms and 7.1 mV in the tongue.

Conclusions: The fixed CMAPs latency obtained despite the vari-ations in the TMS point support the existence of a preferential area ofnerve activation. This area may in all probability be related to theexit skull foramen of the nerves.

doi:10.1016/j.clinph.2008.09.039

12. Corticospinal pathway evaluation in HIV associated myelop-athy—B. Godes, J. Prieto, A. Esteban, A. Traba, A. Polo (Dept. ofClinical Neurophysiology, Hospital G, Universitario G, Marañón,Madrid, Spain)

Objective: Autopsy studies have shown that vacuolar myelop-athy is the most frequent cause of spinal cord disease in HIV pa-tients. This disorder is usually developed in the advanced stagesof AIDS and in association with other dysfunctions of the nervoussystem.

Four long evolution AIDS patients with associated myelopathyhave been studied. Somatosensory-evoked potentials from median(SEPm) and posterior tibial nerves (SEPpt) and motor central conduc-tion (MCC) with transcranial magnetic stimulation were evaluated inall of them. Motor-evoked potentials (MEPs) were recorded in trape-zius, first interosseous dorsalis (FID) and tibialis anterior (TA)muscles.

In one patient, MEPs were markedly delayed in trapezius and FIDand absent in TA. SEPpt and SEPm were very normal too. The otherpatients show slightly delayed MEPs in trapezius and mildly delayedin FID and TA. SEPpt were severely impaired and SEPm were onlymildly abnormal in two of them.

The important abnormalities found in SEPt and in MCC to the TArelated to the mildly delayed responses in SEPm and MCC to FIDpoint to a caudo-cranial gradient of lesion in this myelopathy. Theabnormalities observed in trapezius MEPs suggest the associatedinvolvement of supraspinal segments of the corticospinal pathway.

Conclusion: Corticospinal evaluation in HIV associated-myelopa-thy shows a caudo-cranial gradient of lesion and supraspinalinvolvement.

doi:10.1016/j.clinph.2008.09.040

13. Event-related potentials (N 400) in autistic children—M.Méndez, O. Sans, B. Abril, J.R. Valdizan (Servicio de Neurofisiolo-gia Clinica, Hospital Universitario Miguel Servet, Zaragoza, Spain)

Objective: The present study evaluates the influence of thesemantic context on the N400 activity (latency, amplitude and scalpdistribution), in autistic and Asperger children in comparison to nor-mal children.

Materials and methods: We studied four autistic children, sixwith Asperger syndrome and five normal children between 6 and14 years old diagnosed according to DSM IV. We did an auditorystimulation with pairs of words (congruous and incongruous) two

lists of 0 pairs of words semantically related by categories and 0pairs of non-related words.

Results: The most evident parameter is the increase of the N400latency in autism but not in the Asperger group. The N400 negativityin autism dominates in the left frontocentral area. There is no signif-icant difference in the N400 amplitude in the three groups.

Conclusion: NeurophysiologicalIy, Autism and Asperger use dif-ferent neuronal nets for word-processing. N400 wave is an impor-tant test to follow-up word-processing in these children.

doi:10.1016/j.clinph.2008.09.041

14. P300 in maniac patients—M. Costa, P. Carvajal, M.J. Pablo,C. Almarcegui, J. Alonso-Lej, J.R. Valdizan (Service of ClinicalNeurophysiology, Hospital Universitario Miguel Servet, Zaragoza,Spain)

Introduction and objectives: Cycloid psychosis consists of amood disruption characterized by the combination of depressionand manic episodes between normal mood gaps. The maniac epi-sodes show an over-exited patient, with accelerated thinking andattention deficit. P300 latency is considered a measure of stimulusclassification speed, and P300 amplitude reflects the required cere-bral activity to maintain the working memory. The aim of our studyis to evaluate cognitive function by P300 in cycloid psychosis pa-tients during the manic episode.

Subjects and methods: We study nine patients hospitalized inpsychiatric units and previously diagnosed of manic episode byDSM-IV (F31.X). Patients were under psychopharmacological treat-ment and also clinically stable at the time of register. The age of pa-tients was between 0 and 50 years. They were compared with ninehealthy controls. P300 latency in parietal region and P300 ampli-tudes in parietal and frontal region were measured using the oddballparadigm.

Results: Significant differences between patient and a healthycontrol group were found. Differences were significant in P300latency (Mann–Whitney method, p: 0.003) and in P300 amplitude(Kolmogorov–Smimov method, p: 0.04), and these were more pro-nounced in frontal areas.

Conclusion: Our results suggest that P300 is a useful tool to diag-nose and follow up manic patients.

doi:10.1016/j.clinph.2008.09.042

15. Sequenced SEPs in a case of Morquio syndrome with atlanto-axial subluxation—M.J. Pablo-Zara, M. Costa-Farreny, P. Carvajal-Garcia, A. Saenz de Cabezón, J.R. Valdizan-Usón (Service of ClinicalNeurofisiology, Miguel Servet University Hospital, Zaragoza,Spain)

Introduction: Morquio syndrome is included in mucopolysac-charidoses group IV. Because of a lysosomal storage disease thereis a reduced activity of N-acetylgalactosamine-6-sulfatase (type A)and -galactosidase (type B), that leads to an accumulation of keratinsulfate and chondroitin sulfate in connective and skeletal systems.This autosomal-recessive disorder is characterized by abnormalitiesof the skeletal system, as atlanto-axial subluxation due to a hypo-plastic odontoid process, round vertebrae and pectus carinatum,among others; and cardiac valvular lesions, mild corneal clouding,sensorial hearing loss, dwarfism and normal intelligence. Severityis variable, and complications, such as breathing difficulty and spinalcord compression are often present.

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