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A new system for the computerized analysis of visual, auditory and somatosensory evoked potentials
S86
VIII CONGRESS OF EMG AND RELATED CLINICAL NEUROPHYSIOLOGY
SY. Myotonias, cramps and restless legs.-K. Ricker (NeuroIogische Universi~tsldinik, D-8700 W ~ F.R.G.) The recording of spontaneous activity plays an important part in the electromyographic analysis of myotonic syndromes and cramps. Often the myotonic runs seen in myotonic dystrophy differ from those in the other myotonic disorders such as myotonia congenita (Thomsen) or generalized recessive myotonia (Becker). In paramyotonia, cooling of the muscle together with muscle work dramatically enhances spontaneous activity. This cold-induced activity results from depolarization of the sarcolemma due to an abnormal functioning of the sodium channel. The associated weakness and stiffness can be prevented by tocainide or mexiletine. Severe cramps and fasciculations may appear in the unusual syndrome of massive unilateral calf hypertrophy associated with lumbar disk disease. These hypertrophic calf muscles show almost constant complex repetitive discharges at rest and even more so after voluntary contraction. Other interesting examples of involuntary muscle contractions or muscular rigidity are local tetanus, Isaacs' syndrome and the stiff-man syndrome (Moersch-Woltman). As far as 'restless legs' are concerned, little can be contributed by the EMG although in few cases restless legs may be a feature of neuropathy.
PS. H-reflex studies with conditioning prestimuli in an animal model of central paresis. Drug e f f e c t s . - J . Rlml~k J. Werner, M. Werner and ELJ. Lehmann (Dept, of N e w rology, University Medical School, GHS Essen, F.R.G.) In 40 rabbits with central pareses induced by experimental allergic encephalitis H-reflexes were elicited by stimulation of the tibial nerve and recorded from the plantar flexor muscles. Conditioning prestimuli at various interstimulus intervals were applied to the ipsilateral or contralateral tibial nerve or to the cortex (by a high voltage transcranial stimulator). These conditioning stimuli induce inhibitory mechanisms with a characteristic time course to be detected by an amplitude reduction of the following H-reflex response. As these inhibitory mechanisms proved to be highly sensitive to demyelinating lesions within the descending central motor fiber tracts, we tested whether they also would reflect influences of drugs with a known effect on the spinal reflex level. The results of experiments using benzodiazepines, barbiturates, various other 'antispastic drugs' a n d - a s a reference-strychnine will be presented.
routine work, the system utilizes an Olivetti M24 personal computer (IBM compatible). The keyboard is equipped with practical function keys, by means of which the parameters of stimulation, amplification, acquisition and printing can be easily and quickly varied. Technical details: 2-4 channels; patient-unit galvanically ground-insulated; automatic measurement of electrode impedance; keyboard-driven parameters of stimulation, amplification, recording and printing; automatic artifact rejection; pretrigger and post-trigger analysis; add sweep/even sweep separation; automatic or manual evaluation of amplitudes and latencies; Fast Fourier Transform; digital filtering; standardized protocols for fast routine work; tracings stored on disk; memorization, recall and averaging of single sweeps; visualization on a 12 in., 16-color display screen with high resolution: patient file storage; printing on A 3 / A 4 paper by a fast 7-color plotter.
PS. Evaluation of inibitory phenomena in the recovery cycle of the trigemino-facial reflex,-R. ~ t i , B. Rossi and C. Giannini (Istituto di Clinica Neurologica, Universith di Pisa, Pisa, Italy) The recovery cycle of late responses (R2-R3) of the trigemino-facial reflex (TFR) shows an inhibitory phase from 80 to 175 msec. We evaluated this process by dividing the tactile and nociceptive components of TFR. In 20 healthy subjects (mean age 27), electric stimuli were effected on the right supraorbital nerve and responses recorded by the lower lid bilaterally. In the first experiment, conditioning stimulus was painless, test one painful; in the second both were painless. Interstimulus interval was increased by 50-100 msec, up to I sec. Integral values of R2 and R3 were evaluated. In the first series the maximum inhibition was at 100-150 msec, 70,80% for R2 and 85% for R3. Subsequently, R2 returned towards basal values at 300-400 msec, R3 persisted at lower levels. In the second series of tests no R3 was recorded and the inhibition of R2 between 200 msec and 1 sec proved to be higher than before. These data emphasize the prevalent inhibition of R3 components during longer intershocks intervals, which suggests that R3 is the expression of nociceptive components of TFR. Moreover. the second experLment shows that this inhibitory phenomenon can be attributed tO a mechanism acting both on tactile and painful inputs.
PS. A new system for the computerized analysis of visual, auditory and somatosensory evoked potentials. M. Rinald~ L. Cotllcelli, M. Mep.zione, F, Paolercio and S. SavMtono (Eye Clinic, 1st School of Medicine, University of Naples, Naples, Italy)
PS. Early detection of neurological involvement during diabetes: a comparison of ele~0physiological data and biochemical aspects.-P.A. Rizzo, G. Pozzessere, E. Valle, M;A. Mollica, S. Morano *, U. Di Mario * and C. Morocuttl (lst. di Clinica Neurologica e * Mediea, 00185 Rome, Italy)
The EREV-85 (Lace Electronics, Pisa) is a new system for the computerized analysis of visual, auditory and somatosensory evoked potentials. Designed for research purposes and
Evoked potentials (visual: VEPs; auditory: BAEPs; somatosensory: SEPs) have been used to detect lesions of the nervous system during the early stages of type 1 and type 2
VIII CONGRESS OF EMG AND RELATED CLINICAL NEUROPHYSIOLOGY
SY. Myotonias, cramps and restless legs.-K. Ricker (NeuroIogische Universi~tsldinik, D-8700 W ~ F.R.G.) The recording of spontaneous activity plays an important part in the electromyographic analysis of myotonic syndromes and cramps. Often the myotonic runs seen in myotonic dystrophy differ from those in the other myotonic disorders such as myotonia congenita (Thomsen) or generalized recessive myotonia (Becker). In paramyotonia, cooling of the muscle together with muscle work dramatically enhances spontaneous activity. This cold-induced activity results from depolarization of the sarcolemma due to an abnormal functioning of the sodium channel. The associated weakness and stiffness can be prevented by tocainide or mexiletine. Severe cramps and fasciculations may appear in the unusual syndrome of massive unilateral calf hypertrophy associated with lumbar disk disease. These hypertrophic calf muscles show almost constant complex repetitive discharges at rest and even more so after voluntary contraction. Other interesting examples of involuntary muscle contractions or muscular rigidity are local tetanus, Isaacs' syndrome and the stiff-man syndrome (Moersch-Woltman). As far as 'restless legs' are concerned, little can be contributed by the EMG although in few cases restless legs may be a feature of neuropathy.
PS. H-reflex studies with conditioning prestimuli in an animal model of central paresis. Drug e f f e c t s . - J . Rlml~k J. Werner, M. Werner and ELJ. Lehmann (Dept, of N e w rology, University Medical School, GHS Essen, F.R.G.) In 40 rabbits with central pareses induced by experimental allergic encephalitis H-reflexes were elicited by stimulation of the tibial nerve and recorded from the plantar flexor muscles. Conditioning prestimuli at various interstimulus intervals were applied to the ipsilateral or contralateral tibial nerve or to the cortex (by a high voltage transcranial stimulator). These conditioning stimuli induce inhibitory mechanisms with a characteristic time course to be detected by an amplitude reduction of the following H-reflex response. As these inhibitory mechanisms proved to be highly sensitive to demyelinating lesions within the descending central motor fiber tracts, we tested whether they also would reflect influences of drugs with a known effect on the spinal reflex level. The results of experiments using benzodiazepines, barbiturates, various other 'antispastic drugs' a n d - a s a reference-strychnine will be presented.
routine work, the system utilizes an Olivetti M24 personal computer (IBM compatible). The keyboard is equipped with practical function keys, by means of which the parameters of stimulation, amplification, acquisition and printing can be easily and quickly varied. Technical details: 2-4 channels; patient-unit galvanically ground-insulated; automatic measurement of electrode impedance; keyboard-driven parameters of stimulation, amplification, recording and printing; automatic artifact rejection; pretrigger and post-trigger analysis; add sweep/even sweep separation; automatic or manual evaluation of amplitudes and latencies; Fast Fourier Transform; digital filtering; standardized protocols for fast routine work; tracings stored on disk; memorization, recall and averaging of single sweeps; visualization on a 12 in., 16-color display screen with high resolution: patient file storage; printing on A 3 / A 4 paper by a fast 7-color plotter.
PS. Evaluation of inibitory phenomena in the recovery cycle of the trigemino-facial reflex,-R. ~ t i , B. Rossi and C. Giannini (Istituto di Clinica Neurologica, Universith di Pisa, Pisa, Italy) The recovery cycle of late responses (R2-R3) of the trigemino-facial reflex (TFR) shows an inhibitory phase from 80 to 175 msec. We evaluated this process by dividing the tactile and nociceptive components of TFR. In 20 healthy subjects (mean age 27), electric stimuli were effected on the right supraorbital nerve and responses recorded by the lower lid bilaterally. In the first experiment, conditioning stimulus was painless, test one painful; in the second both were painless. Interstimulus interval was increased by 50-100 msec, up to I sec. Integral values of R2 and R3 were evaluated. In the first series the maximum inhibition was at 100-150 msec, 70,80% for R2 and 85% for R3. Subsequently, R2 returned towards basal values at 300-400 msec, R3 persisted at lower levels. In the second series of tests no R3 was recorded and the inhibition of R2 between 200 msec and 1 sec proved to be higher than before. These data emphasize the prevalent inhibition of R3 components during longer intershocks intervals, which suggests that R3 is the expression of nociceptive components of TFR. Moreover. the second experLment shows that this inhibitory phenomenon can be attributed tO a mechanism acting both on tactile and painful inputs.
PS. A new system for the computerized analysis of visual, auditory and somatosensory evoked potentials. M. Rinald~ L. Cotllcelli, M. Mep.zione, F, Paolercio and S. SavMtono (Eye Clinic, 1st School of Medicine, University of Naples, Naples, Italy)
PS. Early detection of neurological involvement during diabetes: a comparison of ele~0physiological data and biochemical aspects.-P.A. Rizzo, G. Pozzessere, E. Valle, M;A. Mollica, S. Morano *, U. Di Mario * and C. Morocuttl (lst. di Clinica Neurologica e * Mediea, 00185 Rome, Italy)
The EREV-85 (Lace Electronics, Pisa) is a new system for the computerized analysis of visual, auditory and somatosensory evoked potentials. Designed for research purposes and
Evoked potentials (visual: VEPs; auditory: BAEPs; somatosensory: SEPs) have been used to detect lesions of the nervous system during the early stages of type 1 and type 2