Are multifocal motor neuropathy patients underdiagnosed? An epidemiological survey in Japan

Ai Miyashiro, Naoko Matsui, Yoshimitsu Shimatani, Hiroyuki Nodera, Yuishin Izumi, Satoshi Kuwabara, Tomihiro Imai, Masayuki Baba, Tetsuo Komori, Masahiro Sonoo, Takahiro Mezaki, Jun Kawamata, Takefumi Hitomi, Nobuo Kohara, Kimiyoshi Arimura, Shuji Hashimoto, Kokichi Arisawa, Susumu Kusunoki, Ryuji Kaji

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Introduction: Our objective was to do an epidemiologic survey of patients with multifocal motor neuropathy (MMN) in comparison with those with amyotrophic lateral sclerosis (ALS) in Japan. Methods: In this retrospective study, we examined 46 patients with MMN and 1,051 patients with ALS from major neuromuscular centers in Japan from 2005 to 2009. Diagnosis was based on the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) and the revised El Escorial criteria. The efficacy of intravenous immunoglobulin (IVIg) was also taken into consideration in the diagnosis of MMN. Results: The ratio of MMN to ALS patients (0-0.10) varied among the centers, but mostly converged to 0.05. The prevalence was estimated to be 0.29 MMN patients and 6.63 ALS patients per 100,000 population. Conclusions: The frequency of MMN patients was around 1 out of 20 ALS patients, and MMN was possibly underdiagnosed in some centers.

Original languageEnglish
Pages (from-to)357-361
Number of pages5
JournalMuscle and Nerve
Issue number3
Publication statusPublished - 03-2014

All Science Journal Classification (ASJC) codes

  • Physiology
  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Physiology (medical)


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