{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T10:24:58Z","timestamp":1791195898791,"version":"4.1.0"},"reference-count":21,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2004,10,13]],"date-time":"2004-10-13T00:00:00Z","timestamp":1097625600000},"content-version":"vor","delay-in-days":5340,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Muscle and Nerve"],"published-print":{"date-parts":[[1990,3]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>In most myopathies, the duration of motor unit action potentials (MUAPs) is shorter than normal. However, polyphasic MUAPs of duration longer than 20% of the control mean, (long\u2010duration polyphasic potentials, or LDPPs) may be seen. We therefore analyzed the incidence and meaning of LDPPs using quantitative MUAP analysis in 41 patients with different myopathies. The mean duration of all potentials was reduced in only 64% of patients because LDPPs increased the mean. When only simple potentials were considered, however, the mean duration was decreased in 95% of patients. This observation confirms the need to exclude LDPPs when calculating the mean duration of MUAPs for diagnosis. We found LDPPs most often in chronic polymyositis and in one patient with Becker Muscular Dystrophy. LDPPs are attributed to desynchronization of single\u2010fiber potentials within the MUAP and may be due to slow conduction in regenerating muscle fibers.<\/jats:p>","DOI":"10.1002\/mus.880130315","type":"journal-article","created":{"date-parts":[[2005,1,1]],"date-time":"2005-01-01T09:35:32Z","timestamp":1104572132000},"page":"263-267","source":"Crossref","is-referenced-by-count":57,"title":["Long\u2010duration polyphasic motor unit potentials in myopathies: A quantitative study with pathological correlation"],"prefix":"10.1002","volume":"13","author":[{"given":"Antonino","family":"Uncini","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dale J.","family":"Lange","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert E.","family":"Lovelace","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Murray","family":"Solomon","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Arthur P.","family":"Hays","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2004,10,13]]},"reference":[{"key":"e_1_2_1_2_2","first-page":"205","volume-title":"Pathogenesis of Human Muscular Dystrophies","author":"Buchthal F","year":"1977"},{"key":"e_1_2_1_3_2","first-page":"1","article-title":"Electrophysiological signs of myopathy as related with muscle biopsy","volume":"34","author":"Buchthal F","year":"1977","journal-title":"Acta Neurol (Naples)"},{"key":"e_1_2_1_4_2","doi-asserted-by":"publisher","DOI":"10.1002\/mus.880050403"},{"issue":"266","key":"e_1_2_1_5_2","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1111\/j.0954-6820.1952.tb13380.x","article-title":"Analysis of muscle action potentials as a diagnostic aid in neuromuscular disorders","volume":"142","author":"Buchthal F","year":"1952","journal-title":"Acta Medica Scand"},{"key":"e_1_2_1_6_2","doi-asserted-by":"publisher","DOI":"10.1212\/WNL.3.6.424"},{"key":"e_1_2_1_7_2","first-page":"71","volume-title":"New Developments in Electromyography and Clinical Neurophysiology","author":"Buchthal F","year":"1973"},{"key":"e_1_2_1_8_2","doi-asserted-by":"publisher","DOI":"10.1093\/brain\/88.1.29"},{"key":"e_1_2_1_9_2","first-page":"238","volume-title":"Disorders of Voluntary Muscle","author":"Coers C","year":"1981"},{"key":"e_1_2_1_10_2","doi-asserted-by":"publisher","DOI":"10.1038\/246500a0"},{"key":"e_1_2_1_11_2","doi-asserted-by":"publisher","DOI":"10.1001\/archneur.1976.00500090048010"},{"key":"e_1_2_1_12_2","doi-asserted-by":"publisher","DOI":"10.1001\/archneur.1967.00470230061008"},{"key":"e_1_2_1_13_2","doi-asserted-by":"publisher","DOI":"10.1002\/mus.880010103"},{"key":"e_1_2_1_14_2","doi-asserted-by":"publisher","DOI":"10.1136\/jnnp.12.2.129"},{"key":"e_1_2_1_15_2","doi-asserted-by":"publisher","DOI":"10.1016\/0022-510X(76)90217-3"},{"key":"e_1_2_1_16_2","volume-title":"Statistical theories of mental health sciences","author":"Loro FM","year":"1968"},{"key":"e_1_2_1_17_2","doi-asserted-by":"publisher","DOI":"10.1016\/0022-510X(74)90227-5"},{"key":"e_1_2_1_18_2","first-page":"1","volume-title":"Findings in Normal Subjects","author":"Rosenfalck P","year":"1975"},{"issue":"287","key":"e_1_2_1_19_2","first-page":"1","article-title":"Propagation velocity in human muscle fibers in situ","volume":"70","author":"St\u00e5lberg E","year":"1966","journal-title":"Acta Physiol Scand"},{"key":"e_1_2_1_20_2","doi-asserted-by":"publisher","DOI":"10.1016\/0014-4886(81)90155-2"},{"key":"e_1_2_1_21_2","first-page":"417","volume-title":"A Textbook of Clinical Neurophysiology","author":"Trojaborg W","year":"1987"},{"key":"e_1_2_1_22_2","doi-asserted-by":"publisher","DOI":"10.1212\/WNL.33.11.1453"}],"container-title":["Muscle &amp; 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