Case report: A 7-year-old girl diagnosed of Morquio syndrometype A at using enzimatic analysis in leukocytes and culturedfibroblasts. Sequenced controls of SEP and MRI were carriedout, in order to detect possible spinal cord compression. MRIshowed magnum foramen stenosis with C1 subluxation, causingcompression over the posterior side of the spinal cord. Mediannerves SEP was normal at that time. Following controls showeda decrease in the amplitude responses, suggesting a progressivesomatosensory path dysfunction. The patient is in pre-surgicalevaluation. The kind of surgery indicated is upper cervical spinalfusion.

Conclusion: SEP is a useful tool in the follow-up of Morquiopatients in order to evaluate the possible spinal cord compression.

doi:10.1016/j.clinph.2008.09.043

16. Evoked potentials in patients with differentiated thyroid car-cinoma before and during levothyroxine withdrawal—C. Castañ-eda 1, l.l. Botella 2, E. Caro 1, J.M. León 1, S. Montilla 1, F. Paradinas 1,H.F. Escobar-Morreale 2, J.M. Galan 1 (1 Department of ClinicalNeurophysiology, Hospital Ramón y Cajal, Madrid, Spain,2 Department of Endocrinology, Hospital Ramón y Cajal, Madrid,Spain)

Objective: To determine the sensibility of visual-evoked poten-tials (VEP) and brainstem auditory-evoked potentials (BAEP) as auseful and objective tool to evaluate the changes developed in theCentral Nervous Systems (CNS) in patients with thyroid carcinomaduring the withdrawal of the levothyroxine (T4) therapy, previousto the I-131 whole-body scan (WBS).

Material and methods: VEP and BAEP are carried out on a groupof 16 patients diagnosed of differentiated thyroid cancer and chron-ically treated with levothyroxine: firstly, the day before treatmentwithdrawal; secondly, 5 or 6 days after, and finally, the day beforeWBS is performed.

VEP and BAEP are practiced according to the recommendations ofthe International Federation of Clinical Neurophysiology.

Parameters used were P100 wave latency (ms) and amplitude(cV) in VEP and I, III and V wave latencies, as well as I–III, I–V andIII–V interlatencies in BAEP.

Conclusion: Serum thyroid hormone levels decrease duringlevothyroxine withdrawal associated with several changes inVEP, such as P100 wave latency delay and amplitude decrease,on the third follow-up control study compared with the firstand second. No significant differences were found in the BAEPparameters.

doi:10.1016/j.clinph.2008.09.044

17. Bi and monocular visual acuity objective measurement in-month-old nursing-babies—C. Iznaola Muñoz, J.A. Saez Moreno,F. Martinez Sierra (Servicio Neurofisiologia Clinica, HospitalUniversitario San Cecilio, Granada, Spain)

Introduction: Some functional clinical ophthalmologic studiesare difficult to perform on nursing-babies. However, VEP is a usefultechnique to measure visual acuity (VA) at this age.

Methods: It has been implemented in bi and monocular studieson -month-old nursing-babies. In every trial, visual stimulation an-gle was progressively lesser (2�, 1�, 300, 150 and 7.50) until visual re-sponse disappears.

Results: Sixty-six percentage of babies have 7.50 of binocular VAand the rest 150 of arc.

Forty-four percentage of babies have the same VA in botheyes.

Forty-four percentage of babies have the same bi and monocularVA.

Babies with P100 latency over 75% do not have worse VA.Conclusions: P100 latency is a good predictor of VA in children.

VEPs with different angles are an objective technique to measure VAin children.

doi:10.1016/j.clinph.2008.09.045

18. Pattern reversal visual-evoked potentials evolution in pre-term babies—C. Iznaola-Muñoz, J.A. Saez-Moreno, F. Martinez-Sierra (Servicio Neurofisiologia Clinica, Hospital Universitario SanCecilio, Granada, Spain)

Introduction: There is a high incidence of ophthalmologicalabnormalities in pre-term babies and their clinical examination isusually more difficult than in nursing-babies. As P100 latency relateswith gestational age, it could be a useful technique to assess the mat-urational changes.

Method: Pattern-reversal VEPs have been applied in pre-termbabies at 1 and 2 months after birth using the Sokol et al.method.

Results: P100 was delayed in most pre-term babies comparedwith full-term babies of the same gestational age. There were no dif-ferences in visual acuity (VA) between these babies and normalnursing-babies.

Conclusions: Normal VA associated with delayed P100 suggeststhat the latter is due to maturational effect rather than fixed patho-logical changes.

doi:10.1016/j.clinph.2008.09.046

19. Pattern-reversal visual-evoked potentials in nursing-babies—C. Iznaola Muñoz, J.A. Saez Moreno, F. Martinez Sierra (F. ServicioNeurofisiologia Clinica, Hospital Universitario San Cecilio, Gra-nada, Spain)

Introduction: PEV is a useful technique to study retino-geniculo-cortical pathway in nursing-babies. This pathway study could beuseful for the ambliopy screening in these babies.

Methods: We have applied pattern-reversal VEP on 60healthy-month-old nursing-babies using the methods describedby Sokol et al. bi and monocular explorations are carried outon each baby with 2�, 1�, 300, 150 and 7.50 of visual stimulationangle.

Results: The mean time for all studies was 30 minutes. P100latency increases when stimulation angle decreases both bi andmonocular explorations. P100 amplitude decreased when smallerstimulation angle was used. Latencies mean time in the binocularstudy is 179.3 ms. In monocular stimulation: 180.1 ms the left eyeand 180.46 the right eye.

Conclusions: Check size is inversely proportional to P100 latencyand directly proportional to P100 amplitude.

There are no significant differences between P100 latencies for biand monocular studies. PEV is a useful, reliable and complicatedtechnique to study visual way in nursing-babies.

doi:10.1016/j.clinph.2008.09.047

Society Proceedings / Clinical Neurophysiology 120 (2009) e133–e145 e137