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PS-8-12 Visual evoked potential (VEP) in Minamata disease
Poster session 9. Auditory evoked potentials
I PS-8-1 1 / Alterations of the visual evoked potentials in the polyneuropathy of the hypo-alpha-lipoproteinemy
$103
Ps-g: AUDITORY EVOKED POTENTIALS
Doru Baltag 1, Cristian Popescu a, Florin Topoliceanu z, Maria Filip 2, Doina Azoic~i 2, Valeriu Rusu z. l The
~-S----~ Electric evoked potentials of auditory pathway (by sequential recording of logarithmic time axis)
Reabilitation Hospital, Romania; z The University of Medicine and Pharmacology, la#i, Romania
Masaharu Ishikawa 1, Ginichiro Ichikawa 1, Hideki Saitou Akira Arai 1, Yoshirou Ehara 2. 1Department of
The paper analyses the alterations of the Visual Evoked Potentials at two brothers which have the diagnosis hypo-alphalipoproteinemy (Tangier disease). From the clinical point of view, the two patients, a man 30 years old and a woman 27 years old, present a moderate palpebralis ptosis to the left eye, the diminishing of the visual acuity to the left eye and the male patient presents disorders of the oculomotility to the left eye. The electromiography stood out to both patients neurogenous aspect. The exploring of the lipidic metabolism stood out low values of the alpha-lipoproteins. The specific features of these cases consist in the coexistence of visual disorders. The ophtalmologic investigation stood out the diminishing of the visual acuity to the left eye to both patients. The Visual Evoked Potentials obtained with the help of stimulation with flash, reflect major anomalies of the complex N1P1N2 to the studied female patient. Taking into account the genetic character of the disease, some other members of the family were investigated. There were found alterations of the lipid metabolism at the mother of the two brothers and to the child of the female patient. The findings that we made ask for a pursuit in time at the members of this family, of the clinical, biochemical and electrophysiological alterations.
Otorhinolaryngology, z Division of Computer Science, Juntendo University School of Medicine
[ PS-8-12 I Visual evoked potential (VEP) in Minamata disease
1,
Auditory evoked response includes electorocochreography (ECochG), auditory brain stem response (ABR), middle latency response (MLR), slow vertex response (SVR) and others which are applied for clinical diagnosis of the central lesion. However these responses can be elicited only from the subjects whose hearing acuity are within certain level. So, no information can be obtained with the patients who have central auditory nerve system, if they are suffering from inner ear damage. We tried to make a basic experiment of electric evoked response of auditory pathway by promontory stimuli. Anesthetized adult guinea pigs, weighted approximately 800 g, were used. Promontory stimuli were given by trans-tympanicmembrane electrode which was put on promontory. Electric evoked potentials and auditory evoked potentials were recorded between ipsilateral mastoid to vertex. Sweep time was l0 msec and 50 msec. Recording of auditory response were given prior to electrical response. On the 10 msec analysis, four peaks were recognized similar to the auditory stimuli by the electrical stimuli. But peak latencies and inter peak latencies evoked by electric stimuli were shorter as compared with those of auditory stimuli. On the 50 msec analysis, same results were recognized. Peak latencies were prolonged with the decrease of electric stimuli. And we can indicate every peaks by sequential recording of logarithmic time axis.
Shozo lnayoshi 1, Toru Okajima 2, Toshihide Kumamoto 1. ~ The
Third Department of Internal Medicine, Oita Medical University: 2 Kumamoto Johnan Hospital VEP to pattern reversal monocular full field, nasal, temporal, upper, lower hemifield stimulation and nasal, temporal, upper, lower peripheral field stimulations were recorded from patients with Minamata disease (MD) and control subjects. Comparative analysis were performed with the following results: 1. The most important VEP abnormalities in MD patients were the delay of P100 latency and the reduction of its amplitude which were detected by full field stimulation. 2. P100 latency to nasal and temporal hemifield stimulations was significantly delayed and its amplitude was reduced. Similarly, P100 amplitude was reduced with both upper and lower stimulations. In some of the patients, P100 could not even be identified, reducing the appearance rate. 3. P100 amplitude to nasal, temporal, upper and lower peripheral to be identified in most of the cases. 4. It was not possible to perform an objective assessment of the constriction of the visual fields by VEP testing in patients with Minamata disease but the abnormalities found in PI00 suggest the presence of dysfunction in central visual pathways.
•9-•
Characteristics of midline and temporal components of the human auditory evoked middle-latency responses
Hareaki Seki 1, ltaru Kimura 2, Ayumu Ohnuma 1. 1 Neurological Research Center, Miyagi National Hospital; 2 Department of Neurology, Yamagata National Hospital To investigate the various generators of the auditory evoked middle-latency responses (MLRs) in human, we recorded the MLRs in 23 normal adults (8 males and 15 females) using a balanced non-cephalic electrode. Recording electrodes were disposed over the 16 points of a scull, and they were chiefly arranged on midline and temporal areas. Click stimuli were delivered monaurally at an intensity of 50 dBHL, and we continued to monitor the background E E G and E O G during a recording session. While a subject was awake, MLR recordings at 1.5 Hz stimulation were carried out, and 8 Hz stimulations were also performed. When a subject was confirmed to be sleep stage 2, we repeated to record at 1.5 Hz stimulation. As a result, 18 subjects showed distinct temporal positive peaks in complex records, which had longer latencies than midline Pa waveform. These temporal peaks were prominent when we used the 1.5 Hz click stimuli, however usually disappeared at the rate of 8 Hz. Light sleep often diminished temporal peaks, but still evident in most of the subjects. These facts suggest that the positive peaks in the Pa latency domain consist of complex origins. And moreover, the results in this study may compatible with the previous reports conc/Yrning the cortical recordings in animals and human.
I PS-8-1 1 / Alterations of the visual evoked potentials in the polyneuropathy of the hypo-alpha-lipoproteinemy
$103
Ps-g: AUDITORY EVOKED POTENTIALS
Doru Baltag 1, Cristian Popescu a, Florin Topoliceanu z, Maria Filip 2, Doina Azoic~i 2, Valeriu Rusu z. l The
~-S----~ Electric evoked potentials of auditory pathway (by sequential recording of logarithmic time axis)
Reabilitation Hospital, Romania; z The University of Medicine and Pharmacology, la#i, Romania
Masaharu Ishikawa 1, Ginichiro Ichikawa 1, Hideki Saitou Akira Arai 1, Yoshirou Ehara 2. 1Department of
The paper analyses the alterations of the Visual Evoked Potentials at two brothers which have the diagnosis hypo-alphalipoproteinemy (Tangier disease). From the clinical point of view, the two patients, a man 30 years old and a woman 27 years old, present a moderate palpebralis ptosis to the left eye, the diminishing of the visual acuity to the left eye and the male patient presents disorders of the oculomotility to the left eye. The electromiography stood out to both patients neurogenous aspect. The exploring of the lipidic metabolism stood out low values of the alpha-lipoproteins. The specific features of these cases consist in the coexistence of visual disorders. The ophtalmologic investigation stood out the diminishing of the visual acuity to the left eye to both patients. The Visual Evoked Potentials obtained with the help of stimulation with flash, reflect major anomalies of the complex N1P1N2 to the studied female patient. Taking into account the genetic character of the disease, some other members of the family were investigated. There were found alterations of the lipid metabolism at the mother of the two brothers and to the child of the female patient. The findings that we made ask for a pursuit in time at the members of this family, of the clinical, biochemical and electrophysiological alterations.
Otorhinolaryngology, z Division of Computer Science, Juntendo University School of Medicine
[ PS-8-12 I Visual evoked potential (VEP) in Minamata disease
1,
Auditory evoked response includes electorocochreography (ECochG), auditory brain stem response (ABR), middle latency response (MLR), slow vertex response (SVR) and others which are applied for clinical diagnosis of the central lesion. However these responses can be elicited only from the subjects whose hearing acuity are within certain level. So, no information can be obtained with the patients who have central auditory nerve system, if they are suffering from inner ear damage. We tried to make a basic experiment of electric evoked response of auditory pathway by promontory stimuli. Anesthetized adult guinea pigs, weighted approximately 800 g, were used. Promontory stimuli were given by trans-tympanicmembrane electrode which was put on promontory. Electric evoked potentials and auditory evoked potentials were recorded between ipsilateral mastoid to vertex. Sweep time was l0 msec and 50 msec. Recording of auditory response were given prior to electrical response. On the 10 msec analysis, four peaks were recognized similar to the auditory stimuli by the electrical stimuli. But peak latencies and inter peak latencies evoked by electric stimuli were shorter as compared with those of auditory stimuli. On the 50 msec analysis, same results were recognized. Peak latencies were prolonged with the decrease of electric stimuli. And we can indicate every peaks by sequential recording of logarithmic time axis.
Shozo lnayoshi 1, Toru Okajima 2, Toshihide Kumamoto 1. ~ The
Third Department of Internal Medicine, Oita Medical University: 2 Kumamoto Johnan Hospital VEP to pattern reversal monocular full field, nasal, temporal, upper, lower hemifield stimulation and nasal, temporal, upper, lower peripheral field stimulations were recorded from patients with Minamata disease (MD) and control subjects. Comparative analysis were performed with the following results: 1. The most important VEP abnormalities in MD patients were the delay of P100 latency and the reduction of its amplitude which were detected by full field stimulation. 2. P100 latency to nasal and temporal hemifield stimulations was significantly delayed and its amplitude was reduced. Similarly, P100 amplitude was reduced with both upper and lower stimulations. In some of the patients, P100 could not even be identified, reducing the appearance rate. 3. P100 amplitude to nasal, temporal, upper and lower peripheral to be identified in most of the cases. 4. It was not possible to perform an objective assessment of the constriction of the visual fields by VEP testing in patients with Minamata disease but the abnormalities found in PI00 suggest the presence of dysfunction in central visual pathways.
•9-•
Characteristics of midline and temporal components of the human auditory evoked middle-latency responses
Hareaki Seki 1, ltaru Kimura 2, Ayumu Ohnuma 1. 1 Neurological Research Center, Miyagi National Hospital; 2 Department of Neurology, Yamagata National Hospital To investigate the various generators of the auditory evoked middle-latency responses (MLRs) in human, we recorded the MLRs in 23 normal adults (8 males and 15 females) using a balanced non-cephalic electrode. Recording electrodes were disposed over the 16 points of a scull, and they were chiefly arranged on midline and temporal areas. Click stimuli were delivered monaurally at an intensity of 50 dBHL, and we continued to monitor the background E E G and E O G during a recording session. While a subject was awake, MLR recordings at 1.5 Hz stimulation were carried out, and 8 Hz stimulations were also performed. When a subject was confirmed to be sleep stage 2, we repeated to record at 1.5 Hz stimulation. As a result, 18 subjects showed distinct temporal positive peaks in complex records, which had longer latencies than midline Pa waveform. These temporal peaks were prominent when we used the 1.5 Hz click stimuli, however usually disappeared at the rate of 8 Hz. Light sleep often diminished temporal peaks, but still evident in most of the subjects. These facts suggest that the positive peaks in the Pa latency domain consist of complex origins. And moreover, the results in this study may compatible with the previous reports conc/Yrning the cortical recordings in animals and human.