Communications affich6es/Posters 57S

P59 EVOKED POTENTIALS IN THE DIAGNOSIS OF MULTIPLE

SCLEROSIS

M ~ !~ ~!~@~,T.Sagal~s, V-Gimen°,O.R°mer°, F°Pujadas,J.Sumalla,M.Molins,J,Paluzie,MD.Macia Hospital General Valle Hebr6n. Barcelona. Spain

We examined 49 patients with suspected or confirmed Multiple Sclerosis,clinically categorized according to criteria of MeAlpine in possible (gcases),probable(13cases)and definite(27cases).

All patients had magnetic nuclear resonance (MNR) and multimodal evoked potentials (MEPs): Visual (VEP), Brainstem Auditory (BAEP) and Median Nerve Somatosensory (MNPESS).

Latencies, interhemispheric asymmetries, absences and amplitude anomalies were evaluated and compared with those of a 20 healthy subjects group matched in age. Nonparametric tests demonstrate significant differences in plO0 latency and interocular asymmetry of VEP, N20 latency of MNPESS and alteration of the quotient amplitude of I/V waves of BAEP. These results evidenced the existence of other lesions and allowed refine the diagnostic category of EM in 13 of 22 patients.

The degree of intensity of PE's disturbances showed a correlation with the intensity of clinical disturbance.

The use of multimodal evoked potentials remain essential in evaluation of patients suffering a Multiple Sclerosis.

P6I

BRAINSTEM AUDITORY EVOKED POTENTIALS IN LONG TERM THERAPY WITH CARBAMAZEPINE AND NATRIUM VALPROATE: A CLINICAL AND ELECTROPHYSIOLOGICAL CORRELATION* B__= Galas-Zgorzalewicz, T. Jaskulski, B. Steinborn, Department of Developmental Neurology University School of Medicine, Pozna~ (Poland)

Investigation on changes of brainstem auditory evoked potentials (BAEP) during long lasting treatment of natrium valproate (VPA) and carbamazepine (CBZ) were made for the purpose of complex estimation of results in treatment of epilepsy in children and adolescents. Investigation covered patients 5 to 18 years old to whom VPA and CBZ were administered in monotherapy. A' fluorescence polarization immunoassay (FPIA) has been developed to quantitate VPA and CBZ in plasma using the Abbott TDx analyzer. BAEP to click stimuli were registered by means of Bioscript BST 2100 (GDR) as averaged EEG signals. The response obtained were computer processed and evaluated. BAEP were compared with records made before commencement of antiepileptic treatment. The association of BAEP findings with frequency and type of seizures, duration of epilepsy treatment, plasma drug levels and EEG findings were also taken into account. It was found that long term CBZ and VPA treatment' in therapeutic range of serum drug levels is followed by significantly prolonged absolute latencies of waves Ill and V. Also recorded were prolongation of interpeak latencies I-V (central conducting time) in CBZ and VPA treated cases and I-Ill in CBZ patients. Although plasma levels of CBZ and VPA are considered as a good index for evaluating toxicity of these antiepileptic drugs, however the monitoring of BAEP can be a useful tool to measure drug effects on the acoustic pathway.

* The investigation was financially supported by the Committee of Neurological Sciences of Polish Academy of Sciences

P60 BRAINST~4 AUDITORY EVOKED POTENTIALS IN WILSON'S DISEASZ

W.Laskowska-Studniarska,K.Niedzielska,E.Wali- niowska,J.Ga~da,A.Czlonkewska~Institute of Psy- chiatry and Neurolo&7,Warsaw /Poland/

Almost any combination ef neurologlcal s~gns and symptoms of the motor system may be found in Wilson's disease but there is no clinical proof of the sensory nervous system being invol- ved. Bralnstem auditory evoked potentials /BAEPs/ are a sensitive method to demonstrate abnormal auditory system function even in subclinical le- sion. BAEPs were studied in 33 patients with Wilson's disease: 4 with presymptomatic and 29 with a neurological presentation. The BAEP in- terpeak latencies were considered to be abnor- mal when they were prolonged beyond the control mean + 3 SD. In addition,GT was carried out.The BAEPs were normal in all patients with presympto- matlc stage of disease and in 5 patients with neurological defect. The remaining 24 patients with neurological manifestation had abnormal responses. Marked prolongation of the I-V inter- peak latency accompanied by significant abnor- mality of the III-V interwave separation was the moat common result. The present data demonstrate impaired conduc- tion in the brainstem auditory pathways in most of the patients with a neurological manifesta- tion of Wilson's disease. Changes in the brain- stem /atrophy/ have been revealed in CT appear- ances in only about half of the patients. Thus, the BAEPs seem to be a more sensitive tool for detecting the bralnstem involvement in Wilson's disease.

P62

A MODIFIED VECTOR ANALYSIS OF BAER IN PATIENTS WITH BRAINSTEM VASCULAR DAMAGE AND SPACE OCCUPYING LESION

M. Szabo~ A. Kondacs, T. Krajcso Pandy Kalman County Hospital, Gyula (Hungary)

Primary vascular brainstem damage and secondary brainstem lesion caused by different space occupying lesions can be hardly distinguished from each other by the help with a conventional brainstem auditory evoked response (BAER)analysis. Absolute and interpeak latencies or amplitude ratios can show similar alterations in both of these groups. According to our recent observations a modified Einihoven's 3 channel planar vector analysis of BAER can prove to be sensitive in the deiectation of slight abnormalities.

For this reason 42 patients with brainstem vascular damage and 17 patients with different space occupying lesion that caused signs of brainstem disturbances were investigated by using this method. BAER was recorded from three derivations presumed as sides of an equilateral triangle between vertex and both mastoides.The amplitude of the potential measured on each derivation is thought to be the projection of a dipole vector generated in the centre of the brainstem. From these projections the magnitude and direction of the original vectors can be calculated for each point of the BAER. In patients with primary vascular damage the orientation of the vectors was within a normal limit in spite of abnormalities in latencies,IPL and amplitude ratios. Significant differences from the normal orientation were found regarding the direction of the vectors in patients with space occupying lesion.This alteration can be probably due to distortion of the brainstem.

Summarizing our results we can conclude that modified vector analysis of BAER can give further differential diagnostic information.