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Israel society of EEG and clinical neurophysiology
Electroencephalography and clinical Neurophysiology, 1985, 60: 19P-22P Elsevier Scientific Publishers Ireland, Ltd. Society
proceedings
ISRAEL
SOCIETY
OF EEG
AND
CLINICAL
19P
NEUROPHYS1OLOGY
JerusaLem, November 1, 1983
Chairman: Prof. AMOS D. K O R C Z Y N Dept. of Physiology and Pharmacology. Sackler School of Medicine, Ramat Aviv, Tel Aviv 69978 (Israel) " (Received for publication: July 4, 1984)
1. Diagnosis and management of sleep apnea and narcolepsy. - - G.B. Goode (Kaiser Permanente Medical Center, San Francisco, CA, U.S.A.) Sleep apnea and narcolepsy are the two most common causes of excessive daytime sleeepiness (EDS) which are diagnosable by polysomnography. Sleep apnea has approximately 4 times the prevalence of narcolepsy. While snoring and observed apnea are symptoms of most sleep apnea patients, and while most narcolepsy patients have cataplexy, EDS is the most severe and prevalent s y m p t o m of either condition. Pathological sleep apnea is the hallmark of the polysomnogram diagnosis of sleep apnea, and sleep onset rapid eye movements are the unique polysomnographic abnormality in narcolepsy. Regular daytime naps, analeptic and tricyclic drugs may benefit patients with either disorder. Weight loss, uvulo-palato-pharyngoplasty and tracheostomy may improve symptoms in some sleep apnea patients. Although usually distinct disorders, sleep apnea and narcolepsy sometimes overlap clinically and in polysomnographic abnormalities, and they often respond to the same medicines. A neurochemical disturbance of sleep regulating neurons in the medulla and pons may be important in the pathogenesis of sleep apnea and narcolepsy. 2. The effects of elevated thiopental levels in cats on brain-stem evoked potentials elicited by rapid click repetition rates. - R. Chisin, M. Gafni, E. Zylber-Katz, K. Goiten and H. Sohmer (Hadassah University Hospital, Jerusalem) Therapeutic barbiturate coma is used in critical care medicine for brain protection. This therapy causes loss of the main methods of assessing neurological activity. Since the brain-stem evoked potentials (ABRs) have been shown to be unaltered in sleep and during anesthesia, the aim of this study was to determine the effects of high thiopental levels on brain electrical activity as represented by A B R and EEG. For this purpose, A B R and EEG were recorded in 6 cats receiving increasing doses of thiopental. The A B R was elicited by click stimuli at the intensity of 75 dB and at rates of 2 0 / s e c and 80/sec. Brain-stem transmission time in response to 80/sec clicks was prolonged by 0.2 msec at lower thiopental plasma levels than at a click rate of 20/sec. In addition, the later brain-stem components disappeared at lower thiopental levels when the click rate
was higher. In conclusion the maneuver of increasing click repetition rates has made this examination more sensitive since the ABR was found to be affected by lower thiopental levels when tested with higher click rates. This may be because the barbiturates impair synaptic transmission and increased click rates can be assumed to enhance their effect on synaptic transmission. 3. A single dose of sodium valproate in epileptic children: the effect on visual evoked potentials. - Y. Frank. M. Mintz and M.S. Myslobodsky (Psychobiology Research Unit, Tel Aviv University, Tel Aviv) A single dose of sodium valproate (VPA), given to photosensitive epileptic patients, reduced the amplitude of visual evoked potentials (VEPs) 4 - 5 h after the drug administration (Myslobodsky et al. 1980). This, however, was preceded by facilitation of the SNW ( 2 - 4 h post drug), accompanied by complaints of somnolence and fatigue. We therefore examined the effect of VPA on brain reactivity 1 h after drug administration, at which time the drug may reach a maximal plasma level, and before the appearance of somnolence. This effect was also compared with changes in SNW observed 3 h post drug. The sample consisted of drug-free children (7-14 years) diagnosed as having generalized (n = 4), focal (n = 3) or benign focal (n = 3) epilepsy. After baseline VEP recording from O1 and 0 2 sites, patients were given 10 m g / k g VPA. VEP recording was repeated 1 and 3 h following drug administration. One hour after VPA, reduction of SNW amplitude was observed in the generalized and focal groups, reaching statistical significance only in the first group ( P < 0.05). VEPs recorded during the later session replicated the finding of Myslobodsky et al. (1980), showing recovery of SNW amplitude in most patients. In the benign focal group no significant effects of the drug could be detected. It is proposed that suppression of brain reactivity 1 h after VPA may indicate the therapeutic effect of the drug in generalized epilepsy. 4. Short-latency somatosensory evoked potentials to muscle percussion of the hand. - - H. Pratt, N. Bleich, A. Staff and L. Cohen (Technion, Haifa) Cortical as well as, presumably, sub-cortical potentials were recorded from 20 normal subjects, in response to mechanical
0013-4649/85/$03.30 'Q 1985 Elsevier Scientific Publishers Ireland, Ltd.
20P percussion of the thenar eminence. Nuchal to frontal records included an initial negative component at 21 msec, followed by positivities at 28 and 36 msec. C-prime to frontal records included an initial negativity at 23 msec, followed by positivities at 28 and 44 msec. Recording over the peripheral nerve did not reveal any consistent potentials. Control experiments which included ' o n ' and 'off' activations, loading muscles and percussions of various surfaces, may indicate that the potentials are initiated by fast-adapting muscle spindles. If further control experiments continue to support this, an additional constituent of electrically evoked potentials has been separated, and it may prove useful in the definition of pathologies involving muscle innervation.
5. Visual evoked potentials in optic nerve gliomas. - - Z. Groswasser, A. Kriss, A.M. Halliday and W.I. McDonald (Loewenstein Hospital, Ra'anana, and National Hospital, London, England) Visual evoked potentials were recorded in 25 patients with confirmed anterior visual pathway gliomas. Sixteen of these patients had follow-up recordings with a mean interval of 20 months. Flash responses as well as pattern responses were recorded. In only 8 patients could pattern responses be recorded from the affected eye and they were invariably abnormal, had a degraded wave form and were delayed. In 12 cases with no pattern responses it was possible to elicit flash responses, which in some cases were delayed in comparison to the fellow eye. Pattern evoked potentials proved to be a very useful means of monitoring patients. The attenuation of the P100 and alteration in the occipital distribution of the response following independent half-field stimulation were features sensitive to the involvement of chiasmal fibres.
6. Evaluation of auditory brain-stem evoked potentials following extracorporeal circulation. - - A. Frenkel, M. Himelfarb, E. Shanon and B. Vidne (Department of Otolaryngology, Tel Aviv Medical Center, Tel Aviv) This study attempts to assess the functional integrity of the brain-stem following open-heart surgery. A simple electrophysiological tool was employed - - measurement of auditory brainstem potentials (ABPs). This method has proven to be sensitive and reliable in the early detection of diverse pathological processes in the brain-stem. Recording of ABP, as well as routine audiometry, were performed in 31 patients prior to and post open-heart surgery. Aberrations in ABP were observed in 12 patients: brain-stem conduction time or the I-V interpeak latency was prolonged in 5 patients and shortened in 7 patients. " Concomitant impairment in hearing function was not present and, therefore, these changes most probably reflected a functional alteration in the neurological status of the brain-stem. The values of latency in the ponto-medullary and pontomesencephalic segments of the brain-stem as well as amplitudes of the individual waves were submitted to statistical analysis. Data on follow-up studies in several patients were collected. Although some speculations were raised in an attempt to explain both the prolongation and the shortening of BSCT,
SOCIETY P R O C E E D I N G S further studies, and specifically animal experiments, are needed to clarify the pathogenesis of these changes. Measurements of ABP may prove to be an important adjunct in the overall assessment of the neurological status following open-heart surgery.
7. Sleep structure and periodic leg movements in familial dystonia with diurnal variation. The value of sleep recording in early diagnosis. - - N. Gadoth, H. Costeff, P. Lavie and M. Bechar (Department of Neurology, Beilinson Hospital, Petah Tiqva) In 1971 Segawa et al. described a unique form of basal ganglia disease in Japanese children. This 'hereditary progressive dystonia with marked diurnal fluctuation' was considered to be of familial nature, responded dramatically to treatment with L-DOPA and showed a specific sleep disturbance characterized by increased body movements. Being a rare but treatable disorder, the need for early diagnosis and proper genetic counselling is self-evident. We have encountered two unrelated families afflicted with this disease. All 3 patients were females, but the youngest is only minimally disabled. Sleep studies showed a uniform pattern of sleep structure and abnormal movements. The diagnosis in the youngest patient could easily be missed if a sleep record was not available. Clinical screening of the parents and other family members was negative; however polysomnographic recording disclosed abnormal movements during sleep similar to those of the patients in asymptomatic individuals, establishing the hereditary nature of the disease.
8. Sleep in periodic alternating nystagmus. Its structure and influence on involuntary eye movements. - - N. Gadoth, R.S. Manor and P. Lavie (Department of Neurology, Beilinson Medical Center, Petah Tiqva) In recent years it was clearly established that nystagmus of various types disappears during sleep. Polysomnographic studies have also shown that there is a difference in the REM density between vertical and horizontal nystagmus. To the best of our knowledge, in periodic alternating nystagmus (PAN) sleep structure, REM density and presence of nystagmus during sleep have not been reported. As this condition is probably unique among the various forms of nystagmus and reflects disinhibition of the central vestibular apparatus in the brainstem tegmentum, we studied, using polysomnographic recording, a 62-year-old patient with classical PAN. It was clearly shown that nystagmus disappeared during sleep and REM density was markedly decreased. Our finding will be compared to findings in other types of nystagmus and its possible implications will be discussed.
9. Ultradian biological rhythms (short zeitgebers). - - J.J.M. Askenasy and E.D. Weitzman (died June 13, 1983) (Loewenstein Hospital, Raanana, and Montefiore Medical Center, Bronx, U.S.A.) The study of 6 patients suffering from 'periodic sleep movements' showed a movement rhythm of 2 - 6 / m i n . A review
ISRAEL EEG SOCIETY of the literature devoted to this short ultradian biological rhythm showed the existence during sleep of a 1 - 3 / m i n rhythm which paralleled respiration, blood pressure, ventricular cerebrospinal fluid (CSF) pressure and muscle movement. CSF pressure monitoring during sleep showed this rhythm in stages 1 and 2 only. Changes of arousal during sleep were found to have a 3 / m i n periodicity, similar to those of heart rate, respiration, muscle events, skin resistance and pupil size. Studies during wakefulness revealed equivalent rhythms in blood pressure, CSF, respiration and arousal. In raised intracranial pressure rhythmic waves of 4 8 min were recorded in the ventricles as changes up to 30 m m Hg during wakefulness. T h r e e / m i n spontaneous changes in arousal level occur in wakefulness without subjective awareness of this. The common pathway of this rhythm appears to be the alpha motoneuron. In the present study the 6 patients were examined during sleep for H reflex rhythmicity. By stimulating continuously at a frequency of 1 / 2 sec, a facilitation effect with a rhythm of 2 6 / m i n in 4 of the 6 patients was obtained. Short ultradian rhythm of 2 6 / m i n would seem to be endogenous from a pacemaker located at the border of the upper brain-stem.
10. Nerve stimulation studies (NSSs) in meningeal carcinomatosis (MC). - - Z. Argov and T. Siegal (Department of Neurology, Hadassah Universil~' Hospital, Jerusalem) Clinical and autopsy findings indicate an involvement of roots and peripheral nerves in MC. However, no systematic NSSs at the time of diagnosis of MC, to evaluate the extent of such involvement, were performed. We designed such a study in 23 MC patients, 15 with no previous neurotoxic chemotherapy and 8 who received vincristine prior to the study. Maximal conduction velocity (MCV), motor and sensory, and minimal F wave latency to distal stimulation were determined in nerves of leg and arm. Patients were subdivided into those who had clinical involvement of roots and nerves (symptomatic) and those who had not. Motor MCVs in the legs were at the lower range of normal (43.1 + 2.8 in group A and 44.4 + 2.2 m / s e e in group B), significantly lower ( P < 0.008) than in cancer control group (15 patients). F waves were usually prolonged in the legs (more than 55 msec latency); group A: 57.5 + 3.8, group B: 55.6 + 2.7. Motor MCV in the arms and sensory MCV in both arm and leg were not affected. W h e n individually considered 14 of 15 symptomatic cases showed abnormalities in motor nerves in the legs (8 in 2 nerves and 6 in one). In 8 non-symptomatic patients 4 had no abnormalities and 4 had one nerve only affected. In conclusion, motor nerves and roots in the legs are frequently involved in MC at the time of diagnosis, probably by direct cancer cell seeding. NSSs should be part of the evaluation of such patients as they correlate well with symptomatology. 11. The value of electrodiagnostic tests in early prediction of the outcome in Bell's palsy. - - I. Sarova-Pinhas and A. Achiron (Department of Neurology, Sheba Medical Center, TeI-Hashomer) Bell's palsy is the most frequent mononeuropathy. Incomplete recovery occurs in about 15% of the patients, and in 5% of
21P them, the palsy remains. Degeneration of the facial nerve can appear even on the first or second day of the palsy. It is therefore important to establish the severity of the nerve damage in the early stage of the disease, to determine a reliable prognosis and to select the patients for therapeutic procedures. One hundred and forty-four patients with complete Bell's palsy were referred to our electromyography unit; the electrodiagnostic examination included: (1) minimal stimulation test (difference and ratio); (2) nerve conduction time; (3) electromyography, and (4) electroneurography. The study investigated the prognostic value of electrophysiologic evaluation of the nerve damage during the first 3 weeks after the onset of the palsy. To predict the outcome of the palsy the results of the electrodiagnostic tests of 92 patients were analysed and used to construct a formula. The results of the electrodiagnostic tests of 42 new patients were applied to the formula, yielding an 89% degree of accuracy when compared with the clinical outcome. On the basis of this study, we suggest using the combination of the results of the electrodiagnostic tests in the formula for early prediction of the outcome in every case of complete Bell's palsy. 12. Evoked response studies in children with chronic renal failure. - - A. Gilai, A. Pomeranz and A. Drukker (Shaare Zedek Medical Center, Jerusalem) This study describes our experience with electrophysiological measurements in young patients with chronic renal failure (CRF; n = 5), on hemodialysis (HD; n = 7), after renal transplantation (T; n = 4) and in control group (C; n = 7). We compared a variety of peripheral and central nerve functions in order to establish the most reliable index of uremic neuropathy. In addition, an attempt was made to localize the major site of neural dysfunction in uremia. Our data show that H D patients are more affected than C R F patients. In T patients no electrophysiological abnormalities were detected. No significant correlation was observed between the degree of renal failure, as measured by serum creatinine (SCR), and peripheral nerve conduction velocity. SCR did, however, correlate significantly with peripheral neuromuscular and central latency measurements, monosynaptic H reflex and brain-stem transmission time. In these latter tests, which are the most sensitive electrophysiological indices of the uremic state, measurements are made along structures which include at least one synaptic junction. We therefore postulate that the region of the nerve terminal, the synapse and postsynaptic membranes are major sites affected by the uremic toxins. 13. An electrophysiological measurement and reporting system. - - A. Gilai and F. Wiener (Shaare Zedek Medical Center, Jerusalem) An electrophysiological measurement and reporting system was developed for motor and sensory nerve conduction studies, evoked response measurements of the brain-stem auditory, visual, and somatosensory potentials, and electroretinography, oculography and nystagmography. The system consists of a commercially available stimulating and recording system; a specially constructed microprocessor system for converting sig-
22P nals into digital form and for marking the signal to denote events of interest; and a microcomputer which accepts the digitized signal and markers and calculates parameters of clinical interest. The microcomputer is programmed to generate test reports which present the measured and calculated results, compares them to normal values adjusted for the patient's age, and displays the measured signal. The report is formatted to full page to fit the patient's chart. The microcomputer collects
SOCIETY P R O C E E D I N G S and manages a data base of all patients seen at the institute. The normal values given in the test reports are derived from selected patients within this data base. The advantage of this system over those currently marketed is that we can accumulate a data base for normal values, and we can program and evaluate new parameters such as signal slope and area for their possible diagnostic significance.
proceedings
ISRAEL
SOCIETY
OF EEG
AND
CLINICAL
19P
NEUROPHYS1OLOGY
JerusaLem, November 1, 1983
Chairman: Prof. AMOS D. K O R C Z Y N Dept. of Physiology and Pharmacology. Sackler School of Medicine, Ramat Aviv, Tel Aviv 69978 (Israel) " (Received for publication: July 4, 1984)
1. Diagnosis and management of sleep apnea and narcolepsy. - - G.B. Goode (Kaiser Permanente Medical Center, San Francisco, CA, U.S.A.) Sleep apnea and narcolepsy are the two most common causes of excessive daytime sleeepiness (EDS) which are diagnosable by polysomnography. Sleep apnea has approximately 4 times the prevalence of narcolepsy. While snoring and observed apnea are symptoms of most sleep apnea patients, and while most narcolepsy patients have cataplexy, EDS is the most severe and prevalent s y m p t o m of either condition. Pathological sleep apnea is the hallmark of the polysomnogram diagnosis of sleep apnea, and sleep onset rapid eye movements are the unique polysomnographic abnormality in narcolepsy. Regular daytime naps, analeptic and tricyclic drugs may benefit patients with either disorder. Weight loss, uvulo-palato-pharyngoplasty and tracheostomy may improve symptoms in some sleep apnea patients. Although usually distinct disorders, sleep apnea and narcolepsy sometimes overlap clinically and in polysomnographic abnormalities, and they often respond to the same medicines. A neurochemical disturbance of sleep regulating neurons in the medulla and pons may be important in the pathogenesis of sleep apnea and narcolepsy. 2. The effects of elevated thiopental levels in cats on brain-stem evoked potentials elicited by rapid click repetition rates. - R. Chisin, M. Gafni, E. Zylber-Katz, K. Goiten and H. Sohmer (Hadassah University Hospital, Jerusalem) Therapeutic barbiturate coma is used in critical care medicine for brain protection. This therapy causes loss of the main methods of assessing neurological activity. Since the brain-stem evoked potentials (ABRs) have been shown to be unaltered in sleep and during anesthesia, the aim of this study was to determine the effects of high thiopental levels on brain electrical activity as represented by A B R and EEG. For this purpose, A B R and EEG were recorded in 6 cats receiving increasing doses of thiopental. The A B R was elicited by click stimuli at the intensity of 75 dB and at rates of 2 0 / s e c and 80/sec. Brain-stem transmission time in response to 80/sec clicks was prolonged by 0.2 msec at lower thiopental plasma levels than at a click rate of 20/sec. In addition, the later brain-stem components disappeared at lower thiopental levels when the click rate
was higher. In conclusion the maneuver of increasing click repetition rates has made this examination more sensitive since the ABR was found to be affected by lower thiopental levels when tested with higher click rates. This may be because the barbiturates impair synaptic transmission and increased click rates can be assumed to enhance their effect on synaptic transmission. 3. A single dose of sodium valproate in epileptic children: the effect on visual evoked potentials. - Y. Frank. M. Mintz and M.S. Myslobodsky (Psychobiology Research Unit, Tel Aviv University, Tel Aviv) A single dose of sodium valproate (VPA), given to photosensitive epileptic patients, reduced the amplitude of visual evoked potentials (VEPs) 4 - 5 h after the drug administration (Myslobodsky et al. 1980). This, however, was preceded by facilitation of the SNW ( 2 - 4 h post drug), accompanied by complaints of somnolence and fatigue. We therefore examined the effect of VPA on brain reactivity 1 h after drug administration, at which time the drug may reach a maximal plasma level, and before the appearance of somnolence. This effect was also compared with changes in SNW observed 3 h post drug. The sample consisted of drug-free children (7-14 years) diagnosed as having generalized (n = 4), focal (n = 3) or benign focal (n = 3) epilepsy. After baseline VEP recording from O1 and 0 2 sites, patients were given 10 m g / k g VPA. VEP recording was repeated 1 and 3 h following drug administration. One hour after VPA, reduction of SNW amplitude was observed in the generalized and focal groups, reaching statistical significance only in the first group ( P < 0.05). VEPs recorded during the later session replicated the finding of Myslobodsky et al. (1980), showing recovery of SNW amplitude in most patients. In the benign focal group no significant effects of the drug could be detected. It is proposed that suppression of brain reactivity 1 h after VPA may indicate the therapeutic effect of the drug in generalized epilepsy. 4. Short-latency somatosensory evoked potentials to muscle percussion of the hand. - - H. Pratt, N. Bleich, A. Staff and L. Cohen (Technion, Haifa) Cortical as well as, presumably, sub-cortical potentials were recorded from 20 normal subjects, in response to mechanical
0013-4649/85/$03.30 'Q 1985 Elsevier Scientific Publishers Ireland, Ltd.
20P percussion of the thenar eminence. Nuchal to frontal records included an initial negative component at 21 msec, followed by positivities at 28 and 36 msec. C-prime to frontal records included an initial negativity at 23 msec, followed by positivities at 28 and 44 msec. Recording over the peripheral nerve did not reveal any consistent potentials. Control experiments which included ' o n ' and 'off' activations, loading muscles and percussions of various surfaces, may indicate that the potentials are initiated by fast-adapting muscle spindles. If further control experiments continue to support this, an additional constituent of electrically evoked potentials has been separated, and it may prove useful in the definition of pathologies involving muscle innervation.
5. Visual evoked potentials in optic nerve gliomas. - - Z. Groswasser, A. Kriss, A.M. Halliday and W.I. McDonald (Loewenstein Hospital, Ra'anana, and National Hospital, London, England) Visual evoked potentials were recorded in 25 patients with confirmed anterior visual pathway gliomas. Sixteen of these patients had follow-up recordings with a mean interval of 20 months. Flash responses as well as pattern responses were recorded. In only 8 patients could pattern responses be recorded from the affected eye and they were invariably abnormal, had a degraded wave form and were delayed. In 12 cases with no pattern responses it was possible to elicit flash responses, which in some cases were delayed in comparison to the fellow eye. Pattern evoked potentials proved to be a very useful means of monitoring patients. The attenuation of the P100 and alteration in the occipital distribution of the response following independent half-field stimulation were features sensitive to the involvement of chiasmal fibres.
6. Evaluation of auditory brain-stem evoked potentials following extracorporeal circulation. - - A. Frenkel, M. Himelfarb, E. Shanon and B. Vidne (Department of Otolaryngology, Tel Aviv Medical Center, Tel Aviv) This study attempts to assess the functional integrity of the brain-stem following open-heart surgery. A simple electrophysiological tool was employed - - measurement of auditory brainstem potentials (ABPs). This method has proven to be sensitive and reliable in the early detection of diverse pathological processes in the brain-stem. Recording of ABP, as well as routine audiometry, were performed in 31 patients prior to and post open-heart surgery. Aberrations in ABP were observed in 12 patients: brain-stem conduction time or the I-V interpeak latency was prolonged in 5 patients and shortened in 7 patients. " Concomitant impairment in hearing function was not present and, therefore, these changes most probably reflected a functional alteration in the neurological status of the brain-stem. The values of latency in the ponto-medullary and pontomesencephalic segments of the brain-stem as well as amplitudes of the individual waves were submitted to statistical analysis. Data on follow-up studies in several patients were collected. Although some speculations were raised in an attempt to explain both the prolongation and the shortening of BSCT,
SOCIETY P R O C E E D I N G S further studies, and specifically animal experiments, are needed to clarify the pathogenesis of these changes. Measurements of ABP may prove to be an important adjunct in the overall assessment of the neurological status following open-heart surgery.
7. Sleep structure and periodic leg movements in familial dystonia with diurnal variation. The value of sleep recording in early diagnosis. - - N. Gadoth, H. Costeff, P. Lavie and M. Bechar (Department of Neurology, Beilinson Hospital, Petah Tiqva) In 1971 Segawa et al. described a unique form of basal ganglia disease in Japanese children. This 'hereditary progressive dystonia with marked diurnal fluctuation' was considered to be of familial nature, responded dramatically to treatment with L-DOPA and showed a specific sleep disturbance characterized by increased body movements. Being a rare but treatable disorder, the need for early diagnosis and proper genetic counselling is self-evident. We have encountered two unrelated families afflicted with this disease. All 3 patients were females, but the youngest is only minimally disabled. Sleep studies showed a uniform pattern of sleep structure and abnormal movements. The diagnosis in the youngest patient could easily be missed if a sleep record was not available. Clinical screening of the parents and other family members was negative; however polysomnographic recording disclosed abnormal movements during sleep similar to those of the patients in asymptomatic individuals, establishing the hereditary nature of the disease.
8. Sleep in periodic alternating nystagmus. Its structure and influence on involuntary eye movements. - - N. Gadoth, R.S. Manor and P. Lavie (Department of Neurology, Beilinson Medical Center, Petah Tiqva) In recent years it was clearly established that nystagmus of various types disappears during sleep. Polysomnographic studies have also shown that there is a difference in the REM density between vertical and horizontal nystagmus. To the best of our knowledge, in periodic alternating nystagmus (PAN) sleep structure, REM density and presence of nystagmus during sleep have not been reported. As this condition is probably unique among the various forms of nystagmus and reflects disinhibition of the central vestibular apparatus in the brainstem tegmentum, we studied, using polysomnographic recording, a 62-year-old patient with classical PAN. It was clearly shown that nystagmus disappeared during sleep and REM density was markedly decreased. Our finding will be compared to findings in other types of nystagmus and its possible implications will be discussed.
9. Ultradian biological rhythms (short zeitgebers). - - J.J.M. Askenasy and E.D. Weitzman (died June 13, 1983) (Loewenstein Hospital, Raanana, and Montefiore Medical Center, Bronx, U.S.A.) The study of 6 patients suffering from 'periodic sleep movements' showed a movement rhythm of 2 - 6 / m i n . A review
ISRAEL EEG SOCIETY of the literature devoted to this short ultradian biological rhythm showed the existence during sleep of a 1 - 3 / m i n rhythm which paralleled respiration, blood pressure, ventricular cerebrospinal fluid (CSF) pressure and muscle movement. CSF pressure monitoring during sleep showed this rhythm in stages 1 and 2 only. Changes of arousal during sleep were found to have a 3 / m i n periodicity, similar to those of heart rate, respiration, muscle events, skin resistance and pupil size. Studies during wakefulness revealed equivalent rhythms in blood pressure, CSF, respiration and arousal. In raised intracranial pressure rhythmic waves of 4 8 min were recorded in the ventricles as changes up to 30 m m Hg during wakefulness. T h r e e / m i n spontaneous changes in arousal level occur in wakefulness without subjective awareness of this. The common pathway of this rhythm appears to be the alpha motoneuron. In the present study the 6 patients were examined during sleep for H reflex rhythmicity. By stimulating continuously at a frequency of 1 / 2 sec, a facilitation effect with a rhythm of 2 6 / m i n in 4 of the 6 patients was obtained. Short ultradian rhythm of 2 6 / m i n would seem to be endogenous from a pacemaker located at the border of the upper brain-stem.
10. Nerve stimulation studies (NSSs) in meningeal carcinomatosis (MC). - - Z. Argov and T. Siegal (Department of Neurology, Hadassah Universil~' Hospital, Jerusalem) Clinical and autopsy findings indicate an involvement of roots and peripheral nerves in MC. However, no systematic NSSs at the time of diagnosis of MC, to evaluate the extent of such involvement, were performed. We designed such a study in 23 MC patients, 15 with no previous neurotoxic chemotherapy and 8 who received vincristine prior to the study. Maximal conduction velocity (MCV), motor and sensory, and minimal F wave latency to distal stimulation were determined in nerves of leg and arm. Patients were subdivided into those who had clinical involvement of roots and nerves (symptomatic) and those who had not. Motor MCVs in the legs were at the lower range of normal (43.1 + 2.8 in group A and 44.4 + 2.2 m / s e e in group B), significantly lower ( P < 0.008) than in cancer control group (15 patients). F waves were usually prolonged in the legs (more than 55 msec latency); group A: 57.5 + 3.8, group B: 55.6 + 2.7. Motor MCV in the arms and sensory MCV in both arm and leg were not affected. W h e n individually considered 14 of 15 symptomatic cases showed abnormalities in motor nerves in the legs (8 in 2 nerves and 6 in one). In 8 non-symptomatic patients 4 had no abnormalities and 4 had one nerve only affected. In conclusion, motor nerves and roots in the legs are frequently involved in MC at the time of diagnosis, probably by direct cancer cell seeding. NSSs should be part of the evaluation of such patients as they correlate well with symptomatology. 11. The value of electrodiagnostic tests in early prediction of the outcome in Bell's palsy. - - I. Sarova-Pinhas and A. Achiron (Department of Neurology, Sheba Medical Center, TeI-Hashomer) Bell's palsy is the most frequent mononeuropathy. Incomplete recovery occurs in about 15% of the patients, and in 5% of
21P them, the palsy remains. Degeneration of the facial nerve can appear even on the first or second day of the palsy. It is therefore important to establish the severity of the nerve damage in the early stage of the disease, to determine a reliable prognosis and to select the patients for therapeutic procedures. One hundred and forty-four patients with complete Bell's palsy were referred to our electromyography unit; the electrodiagnostic examination included: (1) minimal stimulation test (difference and ratio); (2) nerve conduction time; (3) electromyography, and (4) electroneurography. The study investigated the prognostic value of electrophysiologic evaluation of the nerve damage during the first 3 weeks after the onset of the palsy. To predict the outcome of the palsy the results of the electrodiagnostic tests of 92 patients were analysed and used to construct a formula. The results of the electrodiagnostic tests of 42 new patients were applied to the formula, yielding an 89% degree of accuracy when compared with the clinical outcome. On the basis of this study, we suggest using the combination of the results of the electrodiagnostic tests in the formula for early prediction of the outcome in every case of complete Bell's palsy. 12. Evoked response studies in children with chronic renal failure. - - A. Gilai, A. Pomeranz and A. Drukker (Shaare Zedek Medical Center, Jerusalem) This study describes our experience with electrophysiological measurements in young patients with chronic renal failure (CRF; n = 5), on hemodialysis (HD; n = 7), after renal transplantation (T; n = 4) and in control group (C; n = 7). We compared a variety of peripheral and central nerve functions in order to establish the most reliable index of uremic neuropathy. In addition, an attempt was made to localize the major site of neural dysfunction in uremia. Our data show that H D patients are more affected than C R F patients. In T patients no electrophysiological abnormalities were detected. No significant correlation was observed between the degree of renal failure, as measured by serum creatinine (SCR), and peripheral nerve conduction velocity. SCR did, however, correlate significantly with peripheral neuromuscular and central latency measurements, monosynaptic H reflex and brain-stem transmission time. In these latter tests, which are the most sensitive electrophysiological indices of the uremic state, measurements are made along structures which include at least one synaptic junction. We therefore postulate that the region of the nerve terminal, the synapse and postsynaptic membranes are major sites affected by the uremic toxins. 13. An electrophysiological measurement and reporting system. - - A. Gilai and F. Wiener (Shaare Zedek Medical Center, Jerusalem) An electrophysiological measurement and reporting system was developed for motor and sensory nerve conduction studies, evoked response measurements of the brain-stem auditory, visual, and somatosensory potentials, and electroretinography, oculography and nystagmography. The system consists of a commercially available stimulating and recording system; a specially constructed microprocessor system for converting sig-
22P nals into digital form and for marking the signal to denote events of interest; and a microcomputer which accepts the digitized signal and markers and calculates parameters of clinical interest. The microcomputer is programmed to generate test reports which present the measured and calculated results, compares them to normal values adjusted for the patient's age, and displays the measured signal. The report is formatted to full page to fit the patient's chart. The microcomputer collects
SOCIETY P R O C E E D I N G S and manages a data base of all patients seen at the institute. The normal values given in the test reports are derived from selected patients within this data base. The advantage of this system over those currently marketed is that we can accumulate a data base for normal values, and we can program and evaluate new parameters such as signal slope and area for their possible diagnostic significance.