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PS-9-7 Auditory middle latency evoked responses (MLRS) in patients with dementia
Postersession 10. Transcranialmagnetic stimulation (1)
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Auditory middle latency evoked responses (MLRS) in patients with dementia
Syoichiro Tochigi 1, Osamu Takahashi 2, Miho Suzuki 2, Naofumi Tanaka 2, Kazuhito Tsuziuchi 3, Shigeru Sonoda 2, Eiichi Saito 4, Masato Kawakami 5, Toyoaki Sato 5, Haruo Watanabe 6. I Tokyo Metropolitan College of Allied
Medical Sciences; 2 Tokyo Metropolitan Rehabilitation Hospital; 3 School of Medicine, Keio University; 4 Fujita Health University School of Medicine; 5 St. Marianna University School of Medicine; Tokyo Womens' Medical College The human auditory middle latency evoked responses (MLRs) and auditory brainstem responses (ABRs) were simultaneously recorded in 16 patients with senile dementia of Alzheimer's type (SDAT), 46 patients with multi-infarct dementia (MID) and 52 age-matched hospital control subjects. Comparison between the SDAT/MID and age-matched control groups indicated normal ABRs and latency of Pa component, but significant increase in Pa amplitude of SDAT group and decrease in Pb component formation in SDAT/MID groups. The human Pb component of MLRs is postulated to be generated in the thalamus by a cholinergic component of the ascending reticular activating system. This Pb abnormality suggests that the midbrain cholinergic cells in SDAT and MID patients may be dysfunctional.
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study of• middle A latency auditory evoked 9potential using serial recording in mild intelligent disorder
Hidekazu Kamei, Yasuyo Mimori, Katsumi Kurokawa, Yumiko Kaseda, Shigenobu Nakamura. Department of 3rd
Internal Medicine, School of Medicine, University of Hiroshima It was known the intelligent performance was affected by ascending reticular activating system (RAS). We already reported that the Pb (or P1) component of middle latency auditory evoked potential (MAEP) using low frequent stimuli was reduced in some patients with Alzheimer's disease and demented Parkinson disease. And this reduction was recovered with RAS stimulating agent. In this study we attempt to detect the RAS dysfunction of patients with mild intelligent disorder by serial recording MAEE [Subjects andMethod] The subjects were disturbed in intelligent performance mildly, its degree was follows; score of Hasegawa Dementia Scale or mini-mental state examination was over 19 to under 26 points. In MAEP recording we recorded 4 blocks - - each block included 250 counts - - continuously. The interval among 1st to 3rd blocks was 30 seconds, and 3rd to 4th was 5 minutes. [Result] 3 of 5 subjects showed reductions of Pb component in 2nd and 3rd than 1st block. But in 4th one there was no reduction of Pb component. When the administration of methylphenidate Pb reduction that was showed in these cases was improved. [Conclusion] We conclude that RAS may play a role of intelligent performance in some patients with mild intelligent disorder. And our serial MAEP recording is useful method to detect mild RAS dysfunction.
S105
PS-10: TRANSCRANIAL MAGNETIC STIMULATION (1)
I PS-10-1 [ Silent period following tranacranlal magnetic stimulation: a study of retest reliability C. Fritz, H.J. Braune, C. Pylatiuk, C. Wagner. Department of Neurology, Philipps-Unh~ersity Marburg, Germany Transcranial magnetic stimulation of the motor cortex delivered during voluntary activity produces a motor evoked potential (MEP), followed by a temporary suppression of motor activity (silent period). This silent period (SP) has been reported to be a sensitive neurophysiological parameter, especially in the assessment of distinct central motor dysfunction. In the present study we analyzed the retest-stability of the silent period in 15 healthy volunteers. Standardized transcranial magnetic stimulation during sustained muscle contraction was performed at the vertex. Responses were recorded from abductor digiti minimi muscle. All measurements were repeated 3 days and 7 days after the first investigation. The mean duration of the silent period (day 1) was 138 4- 39 ms on the right and 137 4- 38 ms on the left side. The mean difference between right and left side was 8 4- ms. Comparison between the initially obtained results and the results of the repeated measurements showed a high reproducability. Except in one case, the intraindividual variation of the silent period duration did not exceed 15%. No statistically significant influence of sex or age was found. Our results confirm the well known finding of a high interindividual variation in the duration of the silent period. However, we found a high retest-stability, indicating that SP determination is a reliable neurophysiological parameter.
[ PS-10-2 [ IntracorUcal facilitation and inhibition after paired magnetic stimulation in man Hiroshi Nakamura 1, Hideki Kitagawa 1, Yoshiharu Kawaguchi 1, Haruo Tsuji l, Haruo Takano 2, Shinichi Nakatoh 2. 1Department
of Orthopedic Surgery, Toyama Medical and pharmaceutical University, Toyama, Japan; 2Department of Orthopedic Surgery, Toyama Koshi Rehabilitation Hospital, Toyama, Japan To investigate the changes on the motor cortical excitability, we recorded the evoked spinal cord potential (ESCP) and the evoked compound muscle action potential (ECMAP) simultaneously after paired transcranial magnetic stimulation with a varying interstimulus interval (ISI) in 6 awake subjects (5 males, 1 female, 37-73 years). Magnetic stimulation was delivered by MAGSTIM 200 stimulators connected to the Double Cone Coil through Bistim Module. Paired stimuli were delivered at ISis of 2---800 ms. Intensities of conditioning stimuli were varied from submotor threshold to supramotor threshold. The induced effects depended on the conditioning stimulus intensity. At a low stimulus intensity, there was inhibition at short ISis (2 ms, 5 ms) on both ESCP and ECMAP. At a high intensity, both ESCP and ECMAP facilitated at an ISI of 25 ms, and inhibited at longer ISis (100 ms, 200 ms). Both facilitation and inhibition were prominent in later l-waves. Strong conditioning stimulus induced more remarkable inhibition at longer ISls. These results suggest that the transcranial magnetic stimulation alters the motor cortical excitability by affecting the synaptic transmission to corticomotor neurons.
•
Auditory middle latency evoked responses (MLRS) in patients with dementia
Syoichiro Tochigi 1, Osamu Takahashi 2, Miho Suzuki 2, Naofumi Tanaka 2, Kazuhito Tsuziuchi 3, Shigeru Sonoda 2, Eiichi Saito 4, Masato Kawakami 5, Toyoaki Sato 5, Haruo Watanabe 6. I Tokyo Metropolitan College of Allied
Medical Sciences; 2 Tokyo Metropolitan Rehabilitation Hospital; 3 School of Medicine, Keio University; 4 Fujita Health University School of Medicine; 5 St. Marianna University School of Medicine; Tokyo Womens' Medical College The human auditory middle latency evoked responses (MLRs) and auditory brainstem responses (ABRs) were simultaneously recorded in 16 patients with senile dementia of Alzheimer's type (SDAT), 46 patients with multi-infarct dementia (MID) and 52 age-matched hospital control subjects. Comparison between the SDAT/MID and age-matched control groups indicated normal ABRs and latency of Pa component, but significant increase in Pa amplitude of SDAT group and decrease in Pb component formation in SDAT/MID groups. The human Pb component of MLRs is postulated to be generated in the thalamus by a cholinergic component of the ascending reticular activating system. This Pb abnormality suggests that the midbrain cholinergic cells in SDAT and MID patients may be dysfunctional.
•
study of• middle A latency auditory evoked 9potential using serial recording in mild intelligent disorder
Hidekazu Kamei, Yasuyo Mimori, Katsumi Kurokawa, Yumiko Kaseda, Shigenobu Nakamura. Department of 3rd
Internal Medicine, School of Medicine, University of Hiroshima It was known the intelligent performance was affected by ascending reticular activating system (RAS). We already reported that the Pb (or P1) component of middle latency auditory evoked potential (MAEP) using low frequent stimuli was reduced in some patients with Alzheimer's disease and demented Parkinson disease. And this reduction was recovered with RAS stimulating agent. In this study we attempt to detect the RAS dysfunction of patients with mild intelligent disorder by serial recording MAEE [Subjects andMethod] The subjects were disturbed in intelligent performance mildly, its degree was follows; score of Hasegawa Dementia Scale or mini-mental state examination was over 19 to under 26 points. In MAEP recording we recorded 4 blocks - - each block included 250 counts - - continuously. The interval among 1st to 3rd blocks was 30 seconds, and 3rd to 4th was 5 minutes. [Result] 3 of 5 subjects showed reductions of Pb component in 2nd and 3rd than 1st block. But in 4th one there was no reduction of Pb component. When the administration of methylphenidate Pb reduction that was showed in these cases was improved. [Conclusion] We conclude that RAS may play a role of intelligent performance in some patients with mild intelligent disorder. And our serial MAEP recording is useful method to detect mild RAS dysfunction.
S105
PS-10: TRANSCRANIAL MAGNETIC STIMULATION (1)
I PS-10-1 [ Silent period following tranacranlal magnetic stimulation: a study of retest reliability C. Fritz, H.J. Braune, C. Pylatiuk, C. Wagner. Department of Neurology, Philipps-Unh~ersity Marburg, Germany Transcranial magnetic stimulation of the motor cortex delivered during voluntary activity produces a motor evoked potential (MEP), followed by a temporary suppression of motor activity (silent period). This silent period (SP) has been reported to be a sensitive neurophysiological parameter, especially in the assessment of distinct central motor dysfunction. In the present study we analyzed the retest-stability of the silent period in 15 healthy volunteers. Standardized transcranial magnetic stimulation during sustained muscle contraction was performed at the vertex. Responses were recorded from abductor digiti minimi muscle. All measurements were repeated 3 days and 7 days after the first investigation. The mean duration of the silent period (day 1) was 138 4- 39 ms on the right and 137 4- 38 ms on the left side. The mean difference between right and left side was 8 4- ms. Comparison between the initially obtained results and the results of the repeated measurements showed a high reproducability. Except in one case, the intraindividual variation of the silent period duration did not exceed 15%. No statistically significant influence of sex or age was found. Our results confirm the well known finding of a high interindividual variation in the duration of the silent period. However, we found a high retest-stability, indicating that SP determination is a reliable neurophysiological parameter.
[ PS-10-2 [ IntracorUcal facilitation and inhibition after paired magnetic stimulation in man Hiroshi Nakamura 1, Hideki Kitagawa 1, Yoshiharu Kawaguchi 1, Haruo Tsuji l, Haruo Takano 2, Shinichi Nakatoh 2. 1Department
of Orthopedic Surgery, Toyama Medical and pharmaceutical University, Toyama, Japan; 2Department of Orthopedic Surgery, Toyama Koshi Rehabilitation Hospital, Toyama, Japan To investigate the changes on the motor cortical excitability, we recorded the evoked spinal cord potential (ESCP) and the evoked compound muscle action potential (ECMAP) simultaneously after paired transcranial magnetic stimulation with a varying interstimulus interval (ISI) in 6 awake subjects (5 males, 1 female, 37-73 years). Magnetic stimulation was delivered by MAGSTIM 200 stimulators connected to the Double Cone Coil through Bistim Module. Paired stimuli were delivered at ISis of 2---800 ms. Intensities of conditioning stimuli were varied from submotor threshold to supramotor threshold. The induced effects depended on the conditioning stimulus intensity. At a low stimulus intensity, there was inhibition at short ISis (2 ms, 5 ms) on both ESCP and ECMAP. At a high intensity, both ESCP and ECMAP facilitated at an ISI of 25 ms, and inhibited at longer ISis (100 ms, 200 ms). Both facilitation and inhibition were prominent in later l-waves. Strong conditioning stimulus induced more remarkable inhibition at longer ISls. These results suggest that the transcranial magnetic stimulation alters the motor cortical excitability by affecting the synaptic transmission to corticomotor neurons.