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Comparison of the contrast sensitivity test and the visual evoked potential in detection of optic nerve disease in multiple sclerosis
$212 refractory period of transmission of the pattern-reversal VEP in the demyelinated visual pathway and are comparable to findings with the critical frequency of photic driving and psychophysical tests.
P40.08 C O M P A R I S O N OF T H E CONTRAST SENSITIVITY TEST AND T H E VISUAL EVOKED POTENTIAL IN DETECTION OF OPTIC NERVE DISEASE IN MULTIPLE SCLEROSIS.
G. Coral V. Martinelli, T. Locatelli, S. Della Sala and L. Somazzi
routine half field testing (0-16°r) were reviewed. In the records of 10 patients identification of components was uncertain mainly because responses had a widespread distribution. These patients were re-recorded and a more detailed examination performed which included testing of the central ( 0 - 4 ° r ) and peripheral half fields ( 4 - 1 6 ° 0 . This procedure was found to greatly aid identification of macular and paramacular derived components and in distinguishing delays in the macular P100 component from apparent delays, where the paramacular P135 component dominatesa record. Responses to central ( 0 - 4 ° r ) and peripheral (4-16°r) halffield stimulation were algebraically summed and compared to responses recorded to half field (0-16°r) stimulation. A very close agreement was usually found.
(Milan, Italy) The value of contrast sensitivity test (CS) and visual evoked potentials (VEP) in detecting optic nerve disease was compared in 3 4 multiple sclerosis patients. 66 eyes were examined because two patients each had a cataract in one eye. All subjects were selected as having a Snellen acuity of 20/20 after correction when necessary. Examination of spatial CS was carried out with grating patterns which had a square-wave luminance profile. This is a simple two-alternative forced choice test estimating the spatial frequency of 4 cycles/degree. The VEP was performed with a pattern reversal checkerboard at a spatial frequency of 2 cycles/degree. VEP abnormalities were found in 44/66 eyes (66%), while CS test was abnormal in 49/66 eyes (74%). In 36 eyes both VEP and CS were impaired; VEP was the only abnormality in 8 eyes and CS was the only abnormality in 13 eyes. Out of 11 eyes with a past history of optic neuritis, 9 had both investigations abnormal, one had abnormal VEP and one CS. Combined testing with contrast sensitivity and visual evoked potentials was superior to single tests in detection of optic nerve diseases.
P40.09 THE USE OF MACULAR AND PERIPHERAL HALF-FIELD PATTERN S T I M U L A T I O N IN OPTIC NEURITIS AS AN AID TO IDENTIFYING C O M P O N E N T S AND TO D I S T I N G U I S H I N G REAL FROM APPARENT DELAYS.
J. Brecelj and A. Kriss (Ljubljana, Yugoslavia and London, UK) Half-field stimulation studies in healthy subjects have shown that experimental scotomata attenuate the major positive component (P100) distributed over the scalp ipsilateral to the field stimulated and enhance, or leave unaltered, components (P75, N105, P135) over the contralateral scalp (Blumhardt et al, 1978). Scotomatous waveforms are not uncommonly recorded in patients who have recently had an attack of optic neuritis or in patients with an established diagnosis of multiple sclerosis. The records of 44 patients with scotomatous VEP features following
P40.10 M U L T 1 M O D A L EVOKED P O T E N T I A L S IN MULTIPLE SCLEROSIS: USEFULNESS OF SEP 1N RES P O N S E TO P O S T E R I O R TIBIAL NERVE STIMULATION.
Marie-Claude Lavallard-Rousseau. R. Morizot-Koutlidis and S. Meunier (Paris, France) Two series of patients with possible or definite MS were recorded with all three modalities of evoked potentials. In the first series of 100 patients, the SEPs were obtained in response to median nerve stimulation only; in the second series (80 patients) both tibial and median nerves were stimulated. In the first group, the abnormalities of at least one evoked potential were 60%, 47%, 59% (VER pattern shift (PSVER). BAER, SER, respectively). Combining the three types of evoked potentials, this percentage was 88%. Evidence of clinically unsuspected lesions in patients with probable or possible MS was found in 43%, 26%, 27%, respectively. When all three modalities were combined the discovery of subclinical lesions increased to 63%. In the second group, the evidence of clinically unsuspected lesions was found in 40%, 22.5% (PSVER, BAER). Subclinical lesions were found after median and tibial nerve stimulation in 35% and 43.5%, respectively. In all cases but one abnormal SEPs to median nerve were found associated with abnormal responses to tibial nerve stimulation, whereas isolated abnormalities to tibial nerve stimulation were found in 7 cases. It is concluded that SEPs to tibial nerve stimulation are better predictors of demyelination of the lemniscal pathway than responses to median nerve stimulation.
P40.08 C O M P A R I S O N OF T H E CONTRAST SENSITIVITY TEST AND T H E VISUAL EVOKED POTENTIAL IN DETECTION OF OPTIC NERVE DISEASE IN MULTIPLE SCLEROSIS.
G. Coral V. Martinelli, T. Locatelli, S. Della Sala and L. Somazzi
routine half field testing (0-16°r) were reviewed. In the records of 10 patients identification of components was uncertain mainly because responses had a widespread distribution. These patients were re-recorded and a more detailed examination performed which included testing of the central ( 0 - 4 ° r ) and peripheral half fields ( 4 - 1 6 ° 0 . This procedure was found to greatly aid identification of macular and paramacular derived components and in distinguishing delays in the macular P100 component from apparent delays, where the paramacular P135 component dominatesa record. Responses to central ( 0 - 4 ° r ) and peripheral (4-16°r) halffield stimulation were algebraically summed and compared to responses recorded to half field (0-16°r) stimulation. A very close agreement was usually found.
(Milan, Italy) The value of contrast sensitivity test (CS) and visual evoked potentials (VEP) in detecting optic nerve disease was compared in 3 4 multiple sclerosis patients. 66 eyes were examined because two patients each had a cataract in one eye. All subjects were selected as having a Snellen acuity of 20/20 after correction when necessary. Examination of spatial CS was carried out with grating patterns which had a square-wave luminance profile. This is a simple two-alternative forced choice test estimating the spatial frequency of 4 cycles/degree. The VEP was performed with a pattern reversal checkerboard at a spatial frequency of 2 cycles/degree. VEP abnormalities were found in 44/66 eyes (66%), while CS test was abnormal in 49/66 eyes (74%). In 36 eyes both VEP and CS were impaired; VEP was the only abnormality in 8 eyes and CS was the only abnormality in 13 eyes. Out of 11 eyes with a past history of optic neuritis, 9 had both investigations abnormal, one had abnormal VEP and one CS. Combined testing with contrast sensitivity and visual evoked potentials was superior to single tests in detection of optic nerve diseases.
P40.09 THE USE OF MACULAR AND PERIPHERAL HALF-FIELD PATTERN S T I M U L A T I O N IN OPTIC NEURITIS AS AN AID TO IDENTIFYING C O M P O N E N T S AND TO D I S T I N G U I S H I N G REAL FROM APPARENT DELAYS.
J. Brecelj and A. Kriss (Ljubljana, Yugoslavia and London, UK) Half-field stimulation studies in healthy subjects have shown that experimental scotomata attenuate the major positive component (P100) distributed over the scalp ipsilateral to the field stimulated and enhance, or leave unaltered, components (P75, N105, P135) over the contralateral scalp (Blumhardt et al, 1978). Scotomatous waveforms are not uncommonly recorded in patients who have recently had an attack of optic neuritis or in patients with an established diagnosis of multiple sclerosis. The records of 44 patients with scotomatous VEP features following
P40.10 M U L T 1 M O D A L EVOKED P O T E N T I A L S IN MULTIPLE SCLEROSIS: USEFULNESS OF SEP 1N RES P O N S E TO P O S T E R I O R TIBIAL NERVE STIMULATION.
Marie-Claude Lavallard-Rousseau. R. Morizot-Koutlidis and S. Meunier (Paris, France) Two series of patients with possible or definite MS were recorded with all three modalities of evoked potentials. In the first series of 100 patients, the SEPs were obtained in response to median nerve stimulation only; in the second series (80 patients) both tibial and median nerves were stimulated. In the first group, the abnormalities of at least one evoked potential were 60%, 47%, 59% (VER pattern shift (PSVER). BAER, SER, respectively). Combining the three types of evoked potentials, this percentage was 88%. Evidence of clinically unsuspected lesions in patients with probable or possible MS was found in 43%, 26%, 27%, respectively. When all three modalities were combined the discovery of subclinical lesions increased to 63%. In the second group, the evidence of clinically unsuspected lesions was found in 40%, 22.5% (PSVER, BAER). Subclinical lesions were found after median and tibial nerve stimulation in 35% and 43.5%, respectively. In all cases but one abnormal SEPs to median nerve were found associated with abnormal responses to tibial nerve stimulation, whereas isolated abnormalities to tibial nerve stimulation were found in 7 cases. It is concluded that SEPs to tibial nerve stimulation are better predictors of demyelination of the lemniscal pathway than responses to median nerve stimulation.