The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Yuki Hatanaka - One of the best experts on this subject based on the ideXlab platform.
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utility of Repetitive Nerve Stimulation test for als diagnosis
Clinical Neurophysiology, 2017Co-Authors: Yuki Hatanaka, Mana Higashihara, Takashi Chiba, Yosuke Miyaji, Yasuomi Kawamura, Masahiro SonooAbstract:Abstract Objective Decremental responses in the Repetitive Nerve Stimulation (RNS) test in amyotrophic lateral sclerosis (ALS) patients have been reported, although their possible diagnostic role has received little investigation. We investigated their diagnostic role in differentiation between ALS and cervical spondylotic amyotrophy (CSA), an important ALS mimic especially in Japan. Methods Patients were prospectively enrolled and the diagnosis was confirmed by follow-up. RNS was performed on the abductor pollicis brevis (APB), upper trapezius (trapezius) and deltoid muscles. Results Enrolled subjects consisted of 53 ALS and 37 CSA patients. Abnormal decremental responses (>5%) were observed in 32%, 51% and 75% of ALS patients and 3%, 0% and 20% of CSA patients for the APB, trapezius and deltoid muscles, respectively. The sensitivity for 23 ALS patients with upper-limb onset was 78% for the trapezius and 100% for the deltoid muscles. Conclusions An abnormal decremental response in the trapezius muscle was 100% specific to ALS in comparison with CSA: abnormal decrement in this muscle would strongly suggest ALS. No decrement in the deltoid muscle might exclude ALS in patients having symptoms with upper-limb onset. Significance RNS is useful in differentiation between ALS and CSA.
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diagnostic utility of Repetitive Nerve Stimulation test of the trapezius muscle in amyotrophic lateral sclerosis p4 113
Neurology, 2014Co-Authors: Yuki Hatanaka, Mana Higashihara, Takashi Chiba, Hidehiko Okuma, Takamichi Kanbayashi, Midori Kuwabara, Masahiro SonooAbstract:OBJECTIVE: To investigate the role of Repetitive Nerve Stimulation (RNS) test in the diagnosis of amyotrophic lateral sclerosis (ALS). BACKGROUND: Early and definitive diagnosis of ALS is always a challenge to neurologists. Needle EMG is widely used for ALS diagnosis, although it causes significant pain. We previously documented high incidence of decremental response in RNS in ALS patients, especially in proximal muscles such as deltoid or trapezius muscles. Furthermore, spontaneous activities in the trapezius muscle were sufficiently sensitive and completely specific for ALS in comparison with cervical spondylosis. Cervical spondylotic amyotrophy (CSA) is a disorder commonly described in Japan, which is characterized by definite weakness and atrophy of proximal or distal upper limb muscles, with no or minimal sensory symptoms. Hence, this condition is an important differential diagnosis of ALS. DESIGN/METHODS: We prospectively enrolled ALS and CSA patients. RNS was conducted for 3 muscles, abductor pollicis brevis (APB), upper trapezius (Trap) and deltoid (Del). RESULTS: Enrolled subjects were 35 ALS and 28 CSA patients. The distribution of weakness in CSA patients were proximal in 12, distal in 13, and both proximal and distal in 3 patients. Abnormal decremental responses were observed in 30%, 34% and 63% of ALS patients for the APB, Trap and Del muscles, respectively. The incidence in CSA patients was 4%, 0% and 13%, respectively. CONCLUSIONS: Abnormal decremental response in RNS was a characteristic finding suggestive of ALS. Especially, decrement in the trapezius muscle was completely specific for ALS at least in comparison with CSA, although the sensitivity may not be extremely high. Less invasive RNS may be used as a substitute for needle EMG in order to document lower motor neuron involvement in the trapezius muscle, which is a key muscle in the differential diagnosis between ALS and CSA or other mimicking disorders. Disclosure: Dr. Hatanaka has nothing to disclose. Dr. Chiba has nothing to disclose. Dr. Ookuma has nothing to disclose. Dr. Kanbayashi has nothing to disclose. Dr. Kuwabara has nothing to disclose. Dr. Higashihara has nothing to disclose. Dr. Sonoo has nothing to disclose.
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A new maneuver for Repetitive Nerve Stimulation testing in the trapezius muscle
Muscle & Nerve, 2013Co-Authors: G O Ogawa, Kenichi Kaida, Masahiro Sonoo, Yuki Hatanaka, Keiko KamakuraAbstract:Introduction The Repetitive Nerve Stimulation (RNS) test in the trapezius muscle is used widely for the evaluation of myasthenia gravis. However, pseudofacilitation is often difficult to avoid in this muscle and may compromise the detection of small decremental responses. We have devised a new maneuver to reduce pseudofacilitation. Methods Using our maneuver, the shoulder of a supine subject is elevated passively and is held firmly by the examiner. Four conventional maneuvers as well as ours were compared with regard to pseudofacilitation that was maximal at the second wave in 14 control subjects. Results Pseudofacilitation at the second and fourth waves was the smallest using our maneuver. Up to 15% pseudofacilitation was observed using the other maneuvers. Conclusion Pseudofacilitation in the trapezius muscle is mainly due to shortening of the muscle belly. It can be reduced greatly by shortening the muscle in advance. Muscle Nerve 47: 668–672, 2013
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decremental responses to Repetitive Nerve Stimulation rns in motor neuron disease
Clinical Neurophysiology, 2011Co-Authors: Tomoko Iwanami, Masahiro Sonoo, Yuki Hatanaka, Keiichi Hokkoku, Chizuko Oishi, Teruo ShimizuAbstract:Abstract Objective To clarify the features of decremental responses following Repetitive Nerve Stimulation in patients with motor neuron diseases (MNDs), in comparison with myasthenia gravis (MG). Methods The subjects consisted of 48 MND, 39 generalized MG and 19 ocular MG patients. Six muscles, both proximal and distal muscles, were tested. Results Significant decrements (>5%) in at least one muscle were observed in 83% of the MND patients, and 74% and 47% of the generalized MG and ocular MG patients, respectively. Decrements were more frequently observed in the proximal muscles both in MND and MG patients (deltoid 76% and 62%, and trapezius 71% and 51% for MND and generalized MG, respectively), suggesting lower safety factors in neuromuscular transmission in those muscles. Decrements in the nasalis were rare in MND (8%) in comparison with generalized MG (54%). Conclusions Decremental responses were frequently observed in MND patients. There were small differences between MND and MG regarding the distribution and other features of decrements, such as the degree of the U-shape or the responses to different stimulus frequencies and to brief exercise. Significance These results imply that the underlying mechanism regulating the decrements is common to MND and MG.
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Repetitive Nerve Stimulation of facial muscles in MuSK antibody-positive myasthenia gravis
Muscle & Nerve, 2006Co-Authors: Shin J. Oh, Yuki Hatanaka, Shoji Hemmi, Angela M. Young, Mia L. Scheufele, Sharon P. Nations, Liang Lu, Gwen C. Claussen, Gil I. WolfeAbstract:To better define electrophysiological abnormalities in myasthenia gravis (MG) patients with muscle-specific tyrosine kinase (MuSK) antibodies (Ab), we compared electrophysiological features of 14 MuSK Ab-positive, 73 acetylcholine receptor antibody (AChR Ab)-positive, and 22 MuSK and AChR Ab-negative (seronegative) patients with generalized disease. Repetitive Nerve Stimulation (RNS) abnormalities were observed in 86% of MuSK Ab-positive and 82% of AChR Ab-positive patients but in only 55% of seronegative patients. RNS decrements in the orbicularis oculi were more common and severe in the MuSK Ab-positive patients than the other two groups. Single-fiber electromyography (SFEMG) of the extensor digitorum communis was abnormal in 90% of MuSK Ab-positive patients. The high frequency of RNS abnormalities in facial muscles in the MuSK Ab-positive population reflects the propensity for facial muscle involvement in this form of MG and emphasizes the importance of including facial muscles in RNS protocols when evaluating these patients.
Masahiro Sonoo - One of the best experts on this subject based on the ideXlab platform.
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utility of Repetitive Nerve Stimulation test for als diagnosis
Clinical Neurophysiology, 2017Co-Authors: Yuki Hatanaka, Mana Higashihara, Takashi Chiba, Yosuke Miyaji, Yasuomi Kawamura, Masahiro SonooAbstract:Abstract Objective Decremental responses in the Repetitive Nerve Stimulation (RNS) test in amyotrophic lateral sclerosis (ALS) patients have been reported, although their possible diagnostic role has received little investigation. We investigated their diagnostic role in differentiation between ALS and cervical spondylotic amyotrophy (CSA), an important ALS mimic especially in Japan. Methods Patients were prospectively enrolled and the diagnosis was confirmed by follow-up. RNS was performed on the abductor pollicis brevis (APB), upper trapezius (trapezius) and deltoid muscles. Results Enrolled subjects consisted of 53 ALS and 37 CSA patients. Abnormal decremental responses (>5%) were observed in 32%, 51% and 75% of ALS patients and 3%, 0% and 20% of CSA patients for the APB, trapezius and deltoid muscles, respectively. The sensitivity for 23 ALS patients with upper-limb onset was 78% for the trapezius and 100% for the deltoid muscles. Conclusions An abnormal decremental response in the trapezius muscle was 100% specific to ALS in comparison with CSA: abnormal decrement in this muscle would strongly suggest ALS. No decrement in the deltoid muscle might exclude ALS in patients having symptoms with upper-limb onset. Significance RNS is useful in differentiation between ALS and CSA.
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diagnostic utility of Repetitive Nerve Stimulation test of the trapezius muscle in amyotrophic lateral sclerosis p4 113
Neurology, 2014Co-Authors: Yuki Hatanaka, Mana Higashihara, Takashi Chiba, Hidehiko Okuma, Takamichi Kanbayashi, Midori Kuwabara, Masahiro SonooAbstract:OBJECTIVE: To investigate the role of Repetitive Nerve Stimulation (RNS) test in the diagnosis of amyotrophic lateral sclerosis (ALS). BACKGROUND: Early and definitive diagnosis of ALS is always a challenge to neurologists. Needle EMG is widely used for ALS diagnosis, although it causes significant pain. We previously documented high incidence of decremental response in RNS in ALS patients, especially in proximal muscles such as deltoid or trapezius muscles. Furthermore, spontaneous activities in the trapezius muscle were sufficiently sensitive and completely specific for ALS in comparison with cervical spondylosis. Cervical spondylotic amyotrophy (CSA) is a disorder commonly described in Japan, which is characterized by definite weakness and atrophy of proximal or distal upper limb muscles, with no or minimal sensory symptoms. Hence, this condition is an important differential diagnosis of ALS. DESIGN/METHODS: We prospectively enrolled ALS and CSA patients. RNS was conducted for 3 muscles, abductor pollicis brevis (APB), upper trapezius (Trap) and deltoid (Del). RESULTS: Enrolled subjects were 35 ALS and 28 CSA patients. The distribution of weakness in CSA patients were proximal in 12, distal in 13, and both proximal and distal in 3 patients. Abnormal decremental responses were observed in 30%, 34% and 63% of ALS patients for the APB, Trap and Del muscles, respectively. The incidence in CSA patients was 4%, 0% and 13%, respectively. CONCLUSIONS: Abnormal decremental response in RNS was a characteristic finding suggestive of ALS. Especially, decrement in the trapezius muscle was completely specific for ALS at least in comparison with CSA, although the sensitivity may not be extremely high. Less invasive RNS may be used as a substitute for needle EMG in order to document lower motor neuron involvement in the trapezius muscle, which is a key muscle in the differential diagnosis between ALS and CSA or other mimicking disorders. Disclosure: Dr. Hatanaka has nothing to disclose. Dr. Chiba has nothing to disclose. Dr. Ookuma has nothing to disclose. Dr. Kanbayashi has nothing to disclose. Dr. Kuwabara has nothing to disclose. Dr. Higashihara has nothing to disclose. Dr. Sonoo has nothing to disclose.
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A new maneuver for Repetitive Nerve Stimulation testing in the trapezius muscle
Muscle & Nerve, 2013Co-Authors: G O Ogawa, Kenichi Kaida, Masahiro Sonoo, Yuki Hatanaka, Keiko KamakuraAbstract:Introduction The Repetitive Nerve Stimulation (RNS) test in the trapezius muscle is used widely for the evaluation of myasthenia gravis. However, pseudofacilitation is often difficult to avoid in this muscle and may compromise the detection of small decremental responses. We have devised a new maneuver to reduce pseudofacilitation. Methods Using our maneuver, the shoulder of a supine subject is elevated passively and is held firmly by the examiner. Four conventional maneuvers as well as ours were compared with regard to pseudofacilitation that was maximal at the second wave in 14 control subjects. Results Pseudofacilitation at the second and fourth waves was the smallest using our maneuver. Up to 15% pseudofacilitation was observed using the other maneuvers. Conclusion Pseudofacilitation in the trapezius muscle is mainly due to shortening of the muscle belly. It can be reduced greatly by shortening the muscle in advance. Muscle Nerve 47: 668–672, 2013
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decremental responses to Repetitive Nerve Stimulation rns in motor neuron disease
Clinical Neurophysiology, 2011Co-Authors: Tomoko Iwanami, Masahiro Sonoo, Yuki Hatanaka, Keiichi Hokkoku, Chizuko Oishi, Teruo ShimizuAbstract:Abstract Objective To clarify the features of decremental responses following Repetitive Nerve Stimulation in patients with motor neuron diseases (MNDs), in comparison with myasthenia gravis (MG). Methods The subjects consisted of 48 MND, 39 generalized MG and 19 ocular MG patients. Six muscles, both proximal and distal muscles, were tested. Results Significant decrements (>5%) in at least one muscle were observed in 83% of the MND patients, and 74% and 47% of the generalized MG and ocular MG patients, respectively. Decrements were more frequently observed in the proximal muscles both in MND and MG patients (deltoid 76% and 62%, and trapezius 71% and 51% for MND and generalized MG, respectively), suggesting lower safety factors in neuromuscular transmission in those muscles. Decrements in the nasalis were rare in MND (8%) in comparison with generalized MG (54%). Conclusions Decremental responses were frequently observed in MND patients. There were small differences between MND and MG regarding the distribution and other features of decrements, such as the degree of the U-shape or the responses to different stimulus frequencies and to brief exercise. Significance These results imply that the underlying mechanism regulating the decrements is common to MND and MG.
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single fiber emg and Repetitive Nerve Stimulation of the same extensor digitorum communis muscle in myasthenia gravis
Clinical Neurophysiology, 2001Co-Authors: Masahiro Sonoo, Yuki Hatanaka, Haruo Uesugi, Atsuko Mochizuki, Teruo ShimizuAbstract:Abstract Objective : To compare voluntary single fiber electromyography (v-SFEMG) and Repetitive Nerve Stimulation (RNS) at the same extensor digitorum communis (EDC) muscle in myasthenia gravis (MG). Methods : We examined v-SFEMG and RNS successively on the same day in the same EDC muscle. We studied 45 examinations of both v-SFEMG and RNS in 29 patients suffering from MG, together with examinations of RNS in 30 control subjects. Results : Forty-one of 45 (91%) v-SFEMGs showed abnormal results, whereas only 18/45 (40%) RNSs showed an abnormal decrement. The percentage of decrement showed similar correlations with 3 v-SFEMG parameters: percentage of abnormal pairs, percentage of blocking pairs, and the mean MCD value. Examinations showing a significant decrement in RNS had at least 60%, and usually no less than 90%, abnormal pairs, and 10–80% blocking pairs. Some muscles without a decrement had up to 50% blocking pairs. Conclusions : These results suggest that the blocking phenomenon observed in v-SFEMG is not a direct counterpart of the decrement in RNS. This must be partly because fibers contributing to the decrement are continuously blocked during voluntary contraction, and partly, because smaller motor units explored by v-SFEMG are probably more abnormal in MG than larger motor units mainly contributing to a decrement. Both factors make v-SFEMG much more sensitive than RNS.
Vera Bril - One of the best experts on this subject based on the ideXlab platform.
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Repetitive Nerve Stimulation cutoff values for the diagnosis of myasthenia gravis
Muscle & Nerve, 2017Co-Authors: Alon Abraham, Majed Alabdali, Abdulla Alsulaiman, Ari Breiner, Carolina Barnett, Hans D Katzberg, Leif E Lovblom, Vera BrilAbstract:Introduction Repetitive Nerve Stimulation (RNS) showing ≥ 10% decrement is considered the cutoff for myasthenia gravis (MG), but this has never been validated. The objective of this study was to find an optimal validated cutoff value for decrement on RNS. Methods We performed retrospective chart review of patients who had electrophysiological assessment for possible MG from 2013 to 2015. Results A total of 122 patients with MG and 182 controls were identified. RNS sensitivities for generalized and ocular MG using the traditional ≥10% cutoff value were 46% and 15%, respectively, for frontalis recordings, and 35% and 19%, respectively, for nasalis recordings. Using a decrement cutoff value of 7% for frontalis and 8% for nasalis increased the sensitivities by 6-11%, with specificities of 95-96%. Conclusions For RNS in facial muscles, we suggest a cutoff value of 7-8%, which increases test sensitivity by 6-11%, while preserving high specificity for the diagnosis of MG. Muscle Nerve, 2016 Muscle Nerve 55: 166-170, 2017.
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sensitivity of Repetitive facial Nerve Stimulation in patients with myasthenia gravis
Muscle & Nerve, 2006Co-Authors: Lorne H Zinman, Paul Oconnor, Keith E Dadson, Rita C M Leung, Mylan Ngo, Vera BrilAbstract:Repetitive Stimulation of the facial Nerve is commonly performed in cases of suspected myasthenia gravis (MG) because bulbar weakness is often present, but the most sensitive facial muscle is unknown. We compared the sensitivity of Repetitive Nerve Stimulation (RNS) to the frontalis and nasalis muscles in 244 patients with suspected MG. We found no difference in sensitivity of RNS when recording from these muscles in both ocular and generalized MG. In addition, we confirmed the low sensitivity of RNS for ocular (18%) or generalized (47%) MG. The specificity of facial RNS for both muscles was 100% and, in certain circumstances, may obviate the need for further diagnostic testing.
G H Wieneke - One of the best experts on this subject based on the ideXlab platform.
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ocular myasthenia gravis the diagnostic yield of Repetitive Nerve Stimulation and stimulated single fiber emg of orbicularis oculi muscle and infrared reflection oculography
Muscle & Nerve, 1993Co-Authors: Liam P Oey, G H Wieneke, Tjaard U Hoogenraad, Alexander C Van HuffelenAbstract:For the diagnosis of ocular myasthenia gravis (ocular MG), testing of the muscles close to the affected ones may be important. The relative importance of several methods: stimulated single fiber EMG (stimulated SFEMG), Repetitive Nerve Stimulation test (RNS) of orbicularis oculi muscle, and infrared reflection oculography (IROG) was investigated. Thirty-two patients in whom a diagnosis of ocular MG was considered on clinical grounds were admitted to the study. Based on the results of the three neurophysiological tests, the patients could be divided in three groups: a first group with an abnormal stimulated SFEMG, and an abnormal RNS and/or abnormal IROG; a second group with only a slightly abnormal stimulated SFEMG; and a third group with normal tests in all three tests. The clinical diagnosis of ocular MG was made in all 11 patients of the first group; in 86% (6 of 7) of the patients of the second group; and in 7% (1 of 14) of the patients of the third group. This study demonstrates that the orbicularis oculi muscle is a suitable muscle for stimulated SFEMG in patients with ocular MG, and that the results obtained with this technique showed a better relation with the clinical diagnosis than those of the two other techniques. We also demonstrate that there is no additional value in studying the jitter with different Stimulation rates in patients with suspected ocular MG.
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ocular myasthenia gravis the diagnostic yield of Repetitive Nerve Stimulation and stimulated single fiber emg of orbicularis oculi muscle and infrared reflection oculography
Muscle & Nerve, 1993Co-Authors: G H Wieneke, Tjaard U Hoogenraad, Alexander C Van HuffelenAbstract:For the diagnosis of ocular myasthenia gravis (ocular MG), testing of the muscles close to the affected ones may be important. The relative importance of several methods: stimulated single fiber EMG (stimulated SFEMG), Repetitive Nerve Stimulation test (RNS) of orbicularis oculi muscle, and infrared reflection oculography (IROG) was investigated. Thirty-two patients in whom a diagnosis of ocular MG was considered on clinical grounds were admitted to the study. Based on the results of the three neurophysiological tests, the patients could be divided in three groups: a first group with an abnormal stimulated SFEMG, and an abnormal RNS and/or abnormal IROG; a second group with only a slightly abnormal stimulated SFEMG; and a third group with normal tests in all three tests. The clinical diagnosis of ocular MG was made in all 11 patients of the first group; in 86% (6 of 7) of the patients of the second group; and in 7% (1 of 14) of the patients of the third groups. This study demonstrates that the orbicularis oculi muscle is a suitable muscle for stimulated SFEMG in patients with ocular MG, and that the results obtained with this technique showed a better relation with the clinical diagnosis than those of the two other techniques. We also demonstrate that there is no additional value in studying the jitter with different Stimulation rates in patients with suspected ocular MG. © 1993 John Wiley & Sons, Inc.
Alexander C Van Huffelen - One of the best experts on this subject based on the ideXlab platform.
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ocular myasthenia gravis the diagnostic yield of Repetitive Nerve Stimulation and stimulated single fiber emg of orbicularis oculi muscle and infrared reflection oculography
Muscle & Nerve, 1993Co-Authors: Liam P Oey, G H Wieneke, Tjaard U Hoogenraad, Alexander C Van HuffelenAbstract:For the diagnosis of ocular myasthenia gravis (ocular MG), testing of the muscles close to the affected ones may be important. The relative importance of several methods: stimulated single fiber EMG (stimulated SFEMG), Repetitive Nerve Stimulation test (RNS) of orbicularis oculi muscle, and infrared reflection oculography (IROG) was investigated. Thirty-two patients in whom a diagnosis of ocular MG was considered on clinical grounds were admitted to the study. Based on the results of the three neurophysiological tests, the patients could be divided in three groups: a first group with an abnormal stimulated SFEMG, and an abnormal RNS and/or abnormal IROG; a second group with only a slightly abnormal stimulated SFEMG; and a third group with normal tests in all three tests. The clinical diagnosis of ocular MG was made in all 11 patients of the first group; in 86% (6 of 7) of the patients of the second group; and in 7% (1 of 14) of the patients of the third group. This study demonstrates that the orbicularis oculi muscle is a suitable muscle for stimulated SFEMG in patients with ocular MG, and that the results obtained with this technique showed a better relation with the clinical diagnosis than those of the two other techniques. We also demonstrate that there is no additional value in studying the jitter with different Stimulation rates in patients with suspected ocular MG.