EMG convention for intermittent incapacitates and myotonic disorders determination Long and rehashed short practice tes

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EMG convention for intermittent deadens and myotonic disorders analysis Long and rehashed short practice tests. Dr. Emmanuel Fournier La Salp

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EMG convention for intermittent deadens and myotonic disorders finding Long and rehashed short exercise tests Dr. Emmanuel Fournier La Salpêtrière Hospital, Paris, France

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Overview of the convention The EMG convention incorporates a few tests performed progressively or at the same time so as to decrease the aggregate examination span : Long (5 mn) practice test on right hand, with post-practice rest Repeated short (10s, three circumstances) practice test performed two circumstances, on left hand and on right foot Needle electromyography of five muscles References for the exact depiction of specialized conditions, convention and primary outcomes : Fournier, E.M.Inter , Cachan, 1998, pp 253-262 Fournier et al. Archives of Neurology , 2004, 56: 650-661 Fournier, Rev Neurol (Paris), 2005, in press

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Preparation Three arrangements of surface recording cathodes are introduced Best incitement and recording locales are found Baseline compound muscle activity possibilities (CMAP) are recorded Recording anodes are left in the ideal position all through the examination The designs are triple : Electrodes will serve to various exercise tests A fast nerve conduction consider checks the nonappearance of nerve adjustments. On the off chance that vital, neuromuscular transmission is tried by 3 Hz tedious nerve incitement. Pattern recordings would fill in as reference qualities if an assault of loss of motion happens amid the examination

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Preparation (I, II, III) Recording of the extensor digitorum brevis (EDB) muscle Stimulation of the foremost tibial nerve Electrodes will be utilized for one of the rehashed short exercise tests Recording of the left abductor digiti minimi (ADM) Stimulation of the ulnar nerve Electrodes will be utilized for one of the rehashed short exercise tests Recording of the correct abductor digiti minimi (ADM) Stimulation of the ulnar nerve Electrodes will be utilized for the long exercise test

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Preparation (IV) A swathe avoids enunciation removals and changes in muscle volume amid the activity tests Skin temperature is measured and should be kept up in the vicinity of 32 and 34°C all through the EMG session The object is to keep any diminishing in CMAP abundancy and range which could be brought about by muscle warming amid the examination

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Long exercise test on right hand (I) CMAP is observed before exercise (beat follow) The subject is made a request to spread the little finger as solid as conceivable against resistance amid 5 minutes Brief resting periods (2-3 seconds) are regarded each 30-45 seconds to forestall ischemia After finishing of the activity, the subject is told to totally unwind while CMAP are recorded 2 seconds quickly after discontinuance of activity (second follow) and after that 30 seconds after (third follow)

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Long exercise test (I) Normal changes promptly after exercise Immediately after exercise end, ordinary outcomes are : Slightly diminished sufficiency (- 6 %) of the CMAP Increased length (+38 %) vanishing in 30 seconds If the plentifulness decay is more stamped, it must be precisely watched that nerve incitement is still supramaximal

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Long exercise test (I) Immediate changes after exercise suspension in muscle channelopathies Patients with Paramyotonia Congenita Decreased CMAP adequacy Presence of Post-exercise myotonic possibilities (PEMP) Patients with Periodic Paralysis No change of the CMAP by and large Early diminished plentifulness if an assault of loss of motion has been activated by the activity accomplishment Increased adequacy in patients with Hyperkalemic Periodic Paralysis, particularly when pre-practice CMAP sufficiency was little

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Long exercise test (II) Changes 1-5 minutes after exercise CMAP is recorded each moment amid the initial 5 minutes after exercise end (follows 4-8 on the screen) Normal outcomes amid this rest period are no change of the CMAP as contrasted and pre-practice values : Otherwise, it must be painstakingly watched that nerve incitement is still supramaximal

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Long exercise test (II) Changes 1-5 minutes after exercise in muscle channelopathies Patients with Paramyotonia Congenita Disappearance of PEMP, determination of diminished CMAP plentifulness Patients with Periodic Paralysis No change or dynamic decay of CMAP sufficiency Persistence of the expanded sufficiency if already present, in Hyperkalemic Periodic Paralysis

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Continuation of the long exercise test CMAP of the privilege ADM is recorded at regular intervals amid the 40 minutes rest after exercise end. Recording cathodes and swathe are left on the correct hand During the 5 minutes interim between two recordings, diverse others tests are performed : Repeated short exercise test on the left hand Repeated short exercise test on the correct foot Search for myotonic releases by needle-EMG

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Repeated short exercise test on left hand (I) A moment wrap is introduced on the left hand, and CMAP of the ADM is observed before exercise (best follow) The subject is made a request to spread the little finger as solid as conceivable against resistance amid 10 seconds After finishing of the activity, the subject is told to totally unwind while CMAP are recorded very still : 2 seconds promptly after suspension of activity (second follow) and after that each 7-8 seconds for 50 seconds (follows 3-8 on the screen) This arrangement (10 s compression - 50 s rest) is rehashed three circumstances

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Repeated short exercise test (II) Normal CMAP changes after exercise Immediately after exercise end, ordinary outcomes are : Slightly expanded abundancy (+5 %) of the CMAP (second follow) Return to pre-practice values in 10 seconds (third and next follows) If a plentifulness decay showed up, it must be deliberately watched that nerve incitement is still supramaximal

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Repeated short exercise test (II) CMAP changes between the activities in muscle channelopathies Patients with myotonic disorders Presence of Post-exercise myotonic possibilities (PEMP) quickly after the principal short exercise, particularly in Paramyotonia Congenita Decrease in CMAP adequacy, intensifying or vanishing with rehashing exercise in Paramyotonia Congenita and Myotonia Congenita separately Patients with Periodic Paralysis No change of the CMAP much of the time Increased sufficiency in patients with Hyperkalemic Periodic Paralysis, exacerbating with rehashing exercise, particularly when pre-practice CMAP plentifulness was little

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Long exercise test (III) Back to the correct hand for recording CMAP of the ADM at 10 minutes rest after exercise end. On the off chance that an abundancy decrease showed up, it must be deliberately watched that nerve incitement is still supramaximal

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Repeated short exercise test on right foot CMAP of the EDB is observed before exercise (beat follow) The subject is made a request to raise the toes as solid as conceivable against resistance amid 10 seconds After fulfillment of the activity, the subject is told to totally unwind while CMAP are recorded very still : 2 seconds promptly after suspension of activity (second follow) and after that each 7-8 seconds for 50 seconds (follows 3-8 on the screen) This arrangement (10 s compression - 50 s rest) is rehashed three circumstances

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Long exercise test (IV) Back to the correct hand for recording CMAP of the ADM at 15 minutes rest after exercise end. On the off chance that a plentifulness decrease showed up, it must be painstakingly watched that nerve incitement is still supramaximal

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Needle Electromyography EMG recording of 5 muscles very still and amid willful withdrawal : Deltoid Extensor digitorum brevis First interosseus dorsalis Tibialis front Vastus medialis Searching for myotonic releases : Abundant in myotonic disorders Rare and capricious in Hyperkalemic Periodic Paralysis Absent in Hypokalemic Periodic Paralysis

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End of the long exercise test (V) Back to the correct hand for recording CMAP of the ADM at 20, 25, 30, 35, 40 minutes rest after exercise discontinuance. Changes in CMAP sufficiency between - 20 and +10 % of the pre-practice esteem can be viewed as ordinary. In the event that a plentifulness decay showed up, it must be painstakingly watched that nerve incitement is still supramaximal

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End of the long exercise test (V) Changes 20-40 minutes after exercise in muscle channelopathies Patients with Paramyotonia Congenita Progressive vanishing of the quick post-practice decrease in CMAP abundancy Patients with Periodic Paralysis Progressive establishment of a stamped decay of CMAP sufficiency of the privilege ADM now and again, a loss of motion of the four appendages happens amid the post-practice rest, with checked CMAP adequacy decreases of the privilege ADM, as well as of the left ADM and of the EDB.

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Long exercise test in intermittent incapacitates CMAP changes taking after long exercise in an unaffected patient (An), a patient with hyperkalemic occasional loss of motion (hyperKPP) and T704M sodium channel transformation (B), a patient with hypokalemic intermittent loss of motion (hypoKPP) and R528H calcium channel change (C), a patient with Andersen-Tawil syndrom (ATS) and T309I potassium channel change (D). Pre-work out (top follow) and post-practice recordings (beneath) at various circumstances taking after the trial (Ex) as demonstrated left to the follows. Scale between 2 dabs: 5 ms, 5 mV. ( Adapted from Fournier et al. Ann Neurol 2004 , Fournier Rev Neurol 2005, Bendahhou et al. J Physiol Lond 2005)

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Conclusion Total length of the convention acknowledgment : 50 minutes Preparation : 5 mn; Long exercise : 5 mn; Rest after long exercise with rehashed short activities and needle EMG : 40 mn By contrasting EMG discoveries and reactions with long and rehashed short exercise tests, five primary examples of muscle irregularities could be characterized (Type I-V), each of them comparing to a characterized gathering of particle channel transformations. References for the outcomes : Fournier et al. Chronicles of Neurology , 2004, 56: 650-661

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