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Measurements of 3-dimensional conduction velocity of peripheral nerves with SQUID gradiometry
92P
Society Proceedings/Electroencephalography and clinical Neurophysiology 95 (1995) 86P-94P
with mild demyelination. Nerve conduction studies revealed diffuse slowing of conduction both in motor and sensory nerves with prolonged F wave latency. In addition, focal demyelinating or axonal lesions were overlapped in median and peroneal nerves. Magnetic stimulation demonstrated a markedly increased threshold with disturbance of corticospinal conduction. Sensory evoked potentials showed normal central conduction time. These findings suggest that the underlying pathophysiology of the patient was the slowly progressive degeneration of pyramidal tract and hypomyelination of peripheral nerves with secondary demyelination or axonal degeneration.
stimulated the VR filament thus isolated to record the electrical activity (uEMG) and mechanical force (uT) generated by a single motor unit in the MG muscle. A supramaximal electrical shock was given to the MG nerve to obtain the maximal electrical and mechanical activities of this muscle (EMGma x and Tmax ). By dividing EMGmax by uEMG and Tmax by uT, we estimated the number of motor units in the MG muscle: it was 54 + 15 by EMG and 90 _+ 23 by tension. The number of alpha spinal motor neurons innervating the MG muscle, estimated by morphometry, was 97.5 + 4.2 (J. Comp. Neurol., 1988, 269: 425). Therefore, the present study showed that MUNE based on tension might have better results.
33. Potassium channel suppression as a pathomechanism of myokymic discharge. - K. Arimura, Y. Sonoda, S. Takenaga, Y. Arimura, A. Kurono, S. Suwazono and M. Osame (Kagoshima)
36. Characteristics of the visco-elasticity of the human muscle during visual-guided tracking with the hand. - R. Hayashi and N. Yanagisawa (Matsumoto)
Although the supposed pathomechanism or myokymic discharge is peripheral nerve hyperexcitability, the exact events remain unknown. Isaac's syndrome is a syndrome consisting clinically of muscle cramp and delayed muscle relaxation after exercise. Neuromyotonia, myokymic discharge and fasciculations appear by electromyography (EMG). It is reported to be an antibody mediated autoimmune disorder that suppresses the voltage-gated potassium channel (VGCK). We report a case who showed paresthesia, clinical myokymia without muscle cramp and myokymic discharges (but not neuromyotonia) by EMG. He had an antibody to the thyroid. His symptoms improved with oral prednisolone. This patient was categorized as idiopathic generalized myokymia (IGM). We investigated the effect of the patient's serum on VGCK using the patch-clamp method with PC12 cells cultured with NGF and patient serum. After 6 days' culture with serum, outward current was noted as VGCK was suppressed. The results indicate that some IGM patients may have antibody to VGCK that induces clinical myokymia and myokymic discharge.
To investigate the characteristics of visco-elasticity of the human muscle, we recorded EMG responses of the forearm muscles, a hand position and force when the subjects tracked a target (displayed on a CRT and moved 30 ° at a constant speed of 10°/sec) by flexing the hand 30 ° around the wrist joint against a constant elastic load, 0, 0.7, 1.4 or 2.1 N m / 3 0 °. Six patients with spinocerebellar degeneration (SCD) and 10 age-matched normal subjects were studied. The tracking error in SCD was larger than that in normal controls. The muscle activity of flexor muscles increased according to the increase of load in both groups. An FFT analysis of hand position showed 2 peaks; the first peak corresponded to tracking and the second peak shifted from 4 Hz to 6 Hz when the load increased in normal subjects. In patients, the second peak fluctuated more than that in normal subjects and appeared at a lower frequency, from 3 to 6 Hz. These results suggest that ataxic movements in SCD may be caused by a disturbance of the visco-elasticity of the muscle in response to load change.
34. Re-evaluation of quantitative EEG data of neurosis. - T. Isotani, T. Kuginuki, G. Su, T. Nishimura, Y. Okajima, A. Saito, T. Kinoshita, M. Hashimoto and M. Saito (Osaka)
37. Measurements of 3-dimensional conduction velocity of peripheral nerves with SQUID gradiometry. - Y. Iwase, Y. Yamauchi, T. Mashiko, T. lmada, H. Okazaki, N. Ochiai and I. Hashimoto (Tokyo)
The data from our previous quantitative EEG study of neurotic patients (Isotani, 1993) were re-evaluated. This time we focused on the effect of age as well as the relationship with treatment response. All subjects who participated in the study were right-handed. The neurotic patients and the age-matched normal controls were subclassified into 4 age groups, 20s, 30s, 40s and 50s. The difference from the normal controls was tested using the absolute power values of each frequency band. The younger age groups, 20s and 30s, showed EEG patterns different from those of the normal controls. The neurotic patients showed higher absolute power in delta, theta, and slow alpha frequency bands. There was no statistically significant difference between the neurotics and the normal controls in the 40s and 50s. The laterality of EEG was compared before and after anxiolytic treatment using the Manifest Anxiety Scale to quantify clinical assessment. The patients who showed clinical improvement acquired left predominance of theta and alpha frequency bands after treatment, the similar EEG laterality seen in the normal controls. On the other hand, the EEGs of the treatment refractory patients did not show the above described EEG lateralization.
An attempt was made to apply the SQUID (Superconducting Quantum Interference Device) to the conduction velocity determination of peripheral nerves. The minute magnetic field of the median or ulnar nerve evoked by an electrical stimulation at the wrist of a human volunteer was recorded and plotted in an isomagnetic pattern. This enabled us to recognize a quadrant pole attendant upon depolarization and repolarization. In addition, the current moment was successively and 3-dimensionally estimated by the Marquardt method, which is a technique to find the optimal value. The route of the magnetic current corresponded well to the anatomical pathway of the nerves. It was also noted that an attenuation phenomenon of the current quadrant pole was present in a case of entrapment neuropathy. If the correlation between the number of disturbed nerve fibers and the attenuation of the quadrant pole is established, in the future the magnetic field measurement of the peripheral nerve can possibly be applied clinically to the diagnosis of neuropathy.
35. On the method for motor unit number estimation (MUNE). - K. Arasaki, M. Tamaki and N. Kudo (Tokyo)
We measured lumbrical-interossei difference (2L-INT) and distal motor latency to abductor pollicis brevis (DLAPB) in 59 hands of 50 patients with typical signs and symptoms of carpal tunnel syndrome (CTS) and 34 normal control hands. The compound muscle action potential of second lumbrical and interossei was recorded after stimulation of the median and ulnar nerves at the wrist crease, respectively, using the same active electrode placed lateral to the midpoint of the third metacarpal bone. The reference electrode was placed over the proximal interphalangeal joint of the second digit. In controls the mean 2L-INT
Twenty Sprague-Dawley (S-D) female rats, aged 8 - 9 months, underwent lumbar laminectomy after intraperitoneal administration of urethane (700 m g / k g ) . The medial gastrocnemius (MG) muscle and its nerve were dissected out from the surrounding tissue, and the L5 ventral root (VR) was severed and teased by fine tungsten needles to yield a filament containing a single, functionally intact MG alpha motor axon. We
38. Lumbrical-interossei latency difference test in carpal tunnel syndrome. - N. Tanaka, K. Kondo, Y. Noda, Y. Masakado and N. Chino (Shiobara)
Society Proceedings/Electroencephalography and clinical Neurophysiology 95 (1995) 86P-94P
with mild demyelination. Nerve conduction studies revealed diffuse slowing of conduction both in motor and sensory nerves with prolonged F wave latency. In addition, focal demyelinating or axonal lesions were overlapped in median and peroneal nerves. Magnetic stimulation demonstrated a markedly increased threshold with disturbance of corticospinal conduction. Sensory evoked potentials showed normal central conduction time. These findings suggest that the underlying pathophysiology of the patient was the slowly progressive degeneration of pyramidal tract and hypomyelination of peripheral nerves with secondary demyelination or axonal degeneration.
stimulated the VR filament thus isolated to record the electrical activity (uEMG) and mechanical force (uT) generated by a single motor unit in the MG muscle. A supramaximal electrical shock was given to the MG nerve to obtain the maximal electrical and mechanical activities of this muscle (EMGma x and Tmax ). By dividing EMGmax by uEMG and Tmax by uT, we estimated the number of motor units in the MG muscle: it was 54 + 15 by EMG and 90 _+ 23 by tension. The number of alpha spinal motor neurons innervating the MG muscle, estimated by morphometry, was 97.5 + 4.2 (J. Comp. Neurol., 1988, 269: 425). Therefore, the present study showed that MUNE based on tension might have better results.
33. Potassium channel suppression as a pathomechanism of myokymic discharge. - K. Arimura, Y. Sonoda, S. Takenaga, Y. Arimura, A. Kurono, S. Suwazono and M. Osame (Kagoshima)
36. Characteristics of the visco-elasticity of the human muscle during visual-guided tracking with the hand. - R. Hayashi and N. Yanagisawa (Matsumoto)
Although the supposed pathomechanism or myokymic discharge is peripheral nerve hyperexcitability, the exact events remain unknown. Isaac's syndrome is a syndrome consisting clinically of muscle cramp and delayed muscle relaxation after exercise. Neuromyotonia, myokymic discharge and fasciculations appear by electromyography (EMG). It is reported to be an antibody mediated autoimmune disorder that suppresses the voltage-gated potassium channel (VGCK). We report a case who showed paresthesia, clinical myokymia without muscle cramp and myokymic discharges (but not neuromyotonia) by EMG. He had an antibody to the thyroid. His symptoms improved with oral prednisolone. This patient was categorized as idiopathic generalized myokymia (IGM). We investigated the effect of the patient's serum on VGCK using the patch-clamp method with PC12 cells cultured with NGF and patient serum. After 6 days' culture with serum, outward current was noted as VGCK was suppressed. The results indicate that some IGM patients may have antibody to VGCK that induces clinical myokymia and myokymic discharge.
To investigate the characteristics of visco-elasticity of the human muscle, we recorded EMG responses of the forearm muscles, a hand position and force when the subjects tracked a target (displayed on a CRT and moved 30 ° at a constant speed of 10°/sec) by flexing the hand 30 ° around the wrist joint against a constant elastic load, 0, 0.7, 1.4 or 2.1 N m / 3 0 °. Six patients with spinocerebellar degeneration (SCD) and 10 age-matched normal subjects were studied. The tracking error in SCD was larger than that in normal controls. The muscle activity of flexor muscles increased according to the increase of load in both groups. An FFT analysis of hand position showed 2 peaks; the first peak corresponded to tracking and the second peak shifted from 4 Hz to 6 Hz when the load increased in normal subjects. In patients, the second peak fluctuated more than that in normal subjects and appeared at a lower frequency, from 3 to 6 Hz. These results suggest that ataxic movements in SCD may be caused by a disturbance of the visco-elasticity of the muscle in response to load change.
34. Re-evaluation of quantitative EEG data of neurosis. - T. Isotani, T. Kuginuki, G. Su, T. Nishimura, Y. Okajima, A. Saito, T. Kinoshita, M. Hashimoto and M. Saito (Osaka)
37. Measurements of 3-dimensional conduction velocity of peripheral nerves with SQUID gradiometry. - Y. Iwase, Y. Yamauchi, T. Mashiko, T. lmada, H. Okazaki, N. Ochiai and I. Hashimoto (Tokyo)
The data from our previous quantitative EEG study of neurotic patients (Isotani, 1993) were re-evaluated. This time we focused on the effect of age as well as the relationship with treatment response. All subjects who participated in the study were right-handed. The neurotic patients and the age-matched normal controls were subclassified into 4 age groups, 20s, 30s, 40s and 50s. The difference from the normal controls was tested using the absolute power values of each frequency band. The younger age groups, 20s and 30s, showed EEG patterns different from those of the normal controls. The neurotic patients showed higher absolute power in delta, theta, and slow alpha frequency bands. There was no statistically significant difference between the neurotics and the normal controls in the 40s and 50s. The laterality of EEG was compared before and after anxiolytic treatment using the Manifest Anxiety Scale to quantify clinical assessment. The patients who showed clinical improvement acquired left predominance of theta and alpha frequency bands after treatment, the similar EEG laterality seen in the normal controls. On the other hand, the EEGs of the treatment refractory patients did not show the above described EEG lateralization.
An attempt was made to apply the SQUID (Superconducting Quantum Interference Device) to the conduction velocity determination of peripheral nerves. The minute magnetic field of the median or ulnar nerve evoked by an electrical stimulation at the wrist of a human volunteer was recorded and plotted in an isomagnetic pattern. This enabled us to recognize a quadrant pole attendant upon depolarization and repolarization. In addition, the current moment was successively and 3-dimensionally estimated by the Marquardt method, which is a technique to find the optimal value. The route of the magnetic current corresponded well to the anatomical pathway of the nerves. It was also noted that an attenuation phenomenon of the current quadrant pole was present in a case of entrapment neuropathy. If the correlation between the number of disturbed nerve fibers and the attenuation of the quadrant pole is established, in the future the magnetic field measurement of the peripheral nerve can possibly be applied clinically to the diagnosis of neuropathy.
35. On the method for motor unit number estimation (MUNE). - K. Arasaki, M. Tamaki and N. Kudo (Tokyo)
We measured lumbrical-interossei difference (2L-INT) and distal motor latency to abductor pollicis brevis (DLAPB) in 59 hands of 50 patients with typical signs and symptoms of carpal tunnel syndrome (CTS) and 34 normal control hands. The compound muscle action potential of second lumbrical and interossei was recorded after stimulation of the median and ulnar nerves at the wrist crease, respectively, using the same active electrode placed lateral to the midpoint of the third metacarpal bone. The reference electrode was placed over the proximal interphalangeal joint of the second digit. In controls the mean 2L-INT
Twenty Sprague-Dawley (S-D) female rats, aged 8 - 9 months, underwent lumbar laminectomy after intraperitoneal administration of urethane (700 m g / k g ) . The medial gastrocnemius (MG) muscle and its nerve were dissected out from the surrounding tissue, and the L5 ventral root (VR) was severed and teased by fine tungsten needles to yield a filament containing a single, functionally intact MG alpha motor axon. We
38. Lumbrical-interossei latency difference test in carpal tunnel syndrome. - N. Tanaka, K. Kondo, Y. Noda, Y. Masakado and N. Chino (Shiobara)