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Spontaneous activity recorded from human spinal cord
$76
F83
PSEUDOSELECTIVITYOF THE NEUROMUSCULARBLOCK IN OCULAR MYASTHENIA
EMERYK,B., ROWINSKA,K., NOWAK-Michalska,T., Dept. of Neurology, Warsaw Medical School, Warsaw, Poland The aim of the study was to challenge the opinion, often found in the l i t e r a t u re of the subject, on the true s e l e c t i v i t y of the neuromuscular block in myasthenia. The a l t e r n a t i v e hypothesis is that t h i s s e l e c t i v i t y is only an apparent one, due to the various degrees of the transmission impairment of the various muscles and to the i n s u f f i c i e n t s e n s i t i v i t y of the diagnostic methods. Twelve cases of ocular myasthenia without any symptoms of f a t i g u a b i l i t y of the muscles of the extremities were selected for the study. In a l l cases the results of the classical supramaximal s t i m u l a t i o n were normal. SFEMG was carried out (m.ext.dig.comm. - during weak voluntary contraction) with evaluation of the percent of the potential pairs with blocking, of the percent of normal pot e n t i a l pairs, and of the percent of potential pairs with j i t t e r exceeding loo ~s. The mean j i t t e r was also taken into account. In the majority of cases SFEMG revealed disturbed neuromuscular transmission in the c l i n i c a l l y i n t a c t m.extensor digitorum communis. The results suggest that the s e l e c t i v i t y of the neuromuscular block in ocular myasthenia is only apparent., in f a c t , the impairment of the neuromuscular transmission is generalized and concerns, less or more, a l l the skeletal muscles.
F84
SPONTANEOUSACTIVITY RECORDEDFROM HUMAN SPINAL CORD
ERTEKIN,C., SARICA,Y., ~CKARDELER,L., Dept. of Neurology, Aegean U n i v e r s i t y , Bornova, Izmir, Turkey Using an intrathecal recording technique, the spontaneous e l e c t r i c a l a c t i v i t y (ESPG) of the spinal cord was recorded in 25 normal subjects and 60 patients with peripheral nerve, root and spinal cord disorders. A very f a s t , low-voltage, i r r e g u l a r a c t i v i t y was analysed from the lumbosacral or cervical cord. In normal subjects the spontaneous ESPG was divided into two basic groups: a) Negative-positive diphasic waves, b) p o s i t i v e monophasic or positive-negative diphasic waves. In patients with d i f f u s e peripheral nerve and spinal roots involvement, spontaneous ESPG was s i g n i f i c a n t l y reduced both in frequency and amplitude. While in patients with spastic paraparesis the ESPG became more prominent, and f r e quency and amplitude of the spontaneous a c t i v i t y was s i g n i f i c a n t l y increased. In patients with spinocerebellar a t a x i a , the "abnormal p o s i t i v e p o t e n t i a l s " were observed with t h e i r long duration. I t was concluded that the human spontaneous ESPG is probably originated from interneurons of the posterior horns and f a c i l i t a t e d by peripheral a f f e r e n t inputs and i n h i b i t e d by suprasegmental descending pathways, e s p e c i a l l y the pyramidal t r a c t .
F83
PSEUDOSELECTIVITYOF THE NEUROMUSCULARBLOCK IN OCULAR MYASTHENIA
EMERYK,B., ROWINSKA,K., NOWAK-Michalska,T., Dept. of Neurology, Warsaw Medical School, Warsaw, Poland The aim of the study was to challenge the opinion, often found in the l i t e r a t u re of the subject, on the true s e l e c t i v i t y of the neuromuscular block in myasthenia. The a l t e r n a t i v e hypothesis is that t h i s s e l e c t i v i t y is only an apparent one, due to the various degrees of the transmission impairment of the various muscles and to the i n s u f f i c i e n t s e n s i t i v i t y of the diagnostic methods. Twelve cases of ocular myasthenia without any symptoms of f a t i g u a b i l i t y of the muscles of the extremities were selected for the study. In a l l cases the results of the classical supramaximal s t i m u l a t i o n were normal. SFEMG was carried out (m.ext.dig.comm. - during weak voluntary contraction) with evaluation of the percent of the potential pairs with blocking, of the percent of normal pot e n t i a l pairs, and of the percent of potential pairs with j i t t e r exceeding loo ~s. The mean j i t t e r was also taken into account. In the majority of cases SFEMG revealed disturbed neuromuscular transmission in the c l i n i c a l l y i n t a c t m.extensor digitorum communis. The results suggest that the s e l e c t i v i t y of the neuromuscular block in ocular myasthenia is only apparent., in f a c t , the impairment of the neuromuscular transmission is generalized and concerns, less or more, a l l the skeletal muscles.
F84
SPONTANEOUSACTIVITY RECORDEDFROM HUMAN SPINAL CORD
ERTEKIN,C., SARICA,Y., ~CKARDELER,L., Dept. of Neurology, Aegean U n i v e r s i t y , Bornova, Izmir, Turkey Using an intrathecal recording technique, the spontaneous e l e c t r i c a l a c t i v i t y (ESPG) of the spinal cord was recorded in 25 normal subjects and 60 patients with peripheral nerve, root and spinal cord disorders. A very f a s t , low-voltage, i r r e g u l a r a c t i v i t y was analysed from the lumbosacral or cervical cord. In normal subjects the spontaneous ESPG was divided into two basic groups: a) Negative-positive diphasic waves, b) p o s i t i v e monophasic or positive-negative diphasic waves. In patients with d i f f u s e peripheral nerve and spinal roots involvement, spontaneous ESPG was s i g n i f i c a n t l y reduced both in frequency and amplitude. While in patients with spastic paraparesis the ESPG became more prominent, and f r e quency and amplitude of the spontaneous a c t i v i t y was s i g n i f i c a n t l y increased. In patients with spinocerebellar a t a x i a , the "abnormal p o s i t i v e p o t e n t i a l s " were observed with t h e i r long duration. I t was concluded that the human spontaneous ESPG is probably originated from interneurons of the posterior horns and f a c i l i t a t e d by peripheral a f f e r e n t inputs and i n h i b i t e d by suprasegmental descending pathways, e s p e c i a l l y the pyramidal t r a c t .